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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.3614 | Krzysztof Pachucki | Krzysztof Pachucki | Nuclear vector polarizability correction to hyperfine splitting | 14 pages, submitted to Phys. Rev. A | null | 10.1103/PhysRevA.76.022508 | null | physics.atom-ph nucl-th | null | The interaction of orbital electrons with the charge and magnetic moment of
the nucleus polarizes it, and the detailed description requires a careful
treatment of the nuclear vector polarizability. We present a complete and
closed form expression for the resulting contribution to hyperfine splitting in
light atomic systems.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 10:31:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pachucki",
"Krzysztof",
""
]
] |
0706.3615 | Alessandro Stroppa | A. Stroppa, K. Termentzidis, J. Paier, G. Kresse, J. Hafner | CO adsorption on metal surfaces: a hybrid functional study with plane
wave basis set | 32 pages, 6 tables, 3 figures. (Re)Submitted to Phys. Rev. B; LDA
results added in the tables; minor changes in the text | Phys. Rev. B 76, 195440 (2007) | 10.1103/PhysRevB.76.195440 | null | cond-mat.mtrl-sci | null | We present a detailed study of the adsorption of CO on Cu, Rh, and Pt (111)
surfaces in top and hollow sites. The study has been performed using the local
density approximation, the gradient corrected functional PBE, and the hybrid
Hartree-Fock density functionals PBE0 and HSE03 within the framework of
generalized Kohn-Sham density functional theory using a plane-wave basis set.
As expected, the LDA and GGA functionals show a tendency to favor the hollow
sites, at variance with experimental findings that give the top site as the
most stable adsorption site. The PBE0 and HSE03 functionals reduce this
tendency. In fact, they predict the correct adsorption site for Cu and Rh but
fail for Pt. But even in this case, the hybrid functional destabilizes the
hollow site by 50 meV compared to the PBE functional. The results of the total
energy calculations are presented along with an analysis of the projected
density of states.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 10:39:04 GMT"
},
{
"version": "v2",
"created": "Fri, 21 Sep 2007 13:09:24 GMT"
}
] | 2011-12-30T00:00:00 | [
[
"Stroppa",
"A.",
""
],
[
"Termentzidis",
"K.",
""
],
[
"Paier",
"J.",
""
],
[
"Kresse",
"G.",
""
],
[
"Hafner",
"J.",
""
]
] |
0706.3616 | Jean-Marc Hur\'e | J.-M. Hure, D. Pelat and A. Pierens | Generation of potential/surface density pairs in flat disks Power law
distributions | Accepted for publication in Astronomy & Astrophysics 7 pages, 8
figures, F90-code available at
http://www.obs.u-bordeaux1.fr/radio/JMHure/intro2applawd.html | null | 10.1051/0004-6361:20066808 | null | astro-ph | null | We report a simple method to generate potential/surface density pairs in flat
axially symmetric finite size disks. Potential/surface density pairs consist of
a ``homogeneous'' pair (a closed form expression) corresponding to a uniform
disk, and a ``residual'' pair. This residual component is converted into an
infinite series of integrals over the radial extent of the disk. For a certain
class of surface density distributions (like power laws of the radius), this
series is fully analytical. The extraction of the homogeneous pair is
equivalent to a convergence acceleration technique, in a matematical sense. In
the case of power law distributions, the convergence rate of the residual
series is shown to be cubic inside the source. As a consequence, very accurate
potential values are obtained by low order truncation of the series. At zero
order, relative errors on potential values do not exceed a few percent
typically, and scale with the order N of truncation as 1/N**3. This method is
superior to the classical multipole expansion whose very slow convergence is
often critical for most practical applications.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 10:51:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hure",
"J. -M.",
""
],
[
"Pelat",
"D.",
""
],
[
"Pierens",
"A.",
""
]
] |
0706.3617 | Sergey Peletminskii | A.S. Peletminskii, S.V. Peletminskii, Yu.V. Slyusarenko | On microscopic theory of spin-S Bose-Einstein condensate in a magnetic
field | 11 pages | Physica A 380, 202 (2007) | 10.1016/j.physa.2007.02.107 | null | cond-mat.stat-mech | null | The Bogoliubov model for weakly interacting Bose gas is extended to
Bose-Einstein condensation (BEC) of spin-S atoms in a magnetic field. Equation
for the vectorial order parameter valid at temperature $T\to 0$ is derived and
its particular solution is found. This solution corresponds to the formation of
BEC of atoms with a definite spin projection onto direction of a magnetic
field. We study the thermodynamic stability of the found solution and obtain
the expressions for low-lying collective modes.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 10:53:34 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Peletminskii",
"A. S.",
""
],
[
"Peletminskii",
"S. V.",
""
],
[
"Slyusarenko",
"Yu. V.",
""
]
] |
0706.3618 | Achenef Tesfahun | Achenef Tesfahun | Low Regularity local well-posedness for the 1+3 dimensional
Dirac-Klein-Gordon system | null | null | null | null | math.AP | null | We prove that the Cauchy problem for the Dirac-Klein-Gordon system of
equations in 1+3 dimensions is locally well-posed in a range of Sobolev spaces
for the Dirac spinor and the meson field. The result contains and extends the
earlier known results for the same problem. Our proof relies on the null
structure in the system, and bilinear spacetime estimates of
Klainerman-Machedon type.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 11:21:41 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Tesfahun",
"Achenef",
""
]
] |
0706.3619 | Jamel EL Kamel | Jamel El Kamel and Chokri Yacoub | Almost Everywhere Convergence of Inverse Dunkl Transform on the Real
Line | 9 pages | null | null | null | math.CA | null | In this paper, we will first show that the maximal operator $S_*^\alpha$ of
spherical partial sums $S_R^\alpha$, associated to Dunkl transform on
$\mathbb{R}$ is bounded on $L^p(\mathbb{R}, |x|^{2\alpha+1} dx)$ functions when
$\frac{4(\alpha+1)}{2\alpha+3}<p<\frac{4(\alpha+1)}{2\alpha+1}$, and it implies
that, for every $L^p(\mathbb{R}, |x|^{2\alpha+1} dx)$ function $f(x)$,
$S_R^\alpha f(x)$ converges to $f(x)$ almost everywhere as $R\to \infty$. On
the other hand we obtain a sharp version by showing that $S_*^\alpha$ is
bounded from the Lorentz space $L^{p_i,1}(\mathbb{R}, |x|^{2\alpha+1})$ into
$L^{p_i,\infty}(\mathbb{R}, |x|^{2\alpha+1}),\quad i=0,1$ where
$p_0=\frac{4(\alpha+1)}{2\alpha+3}$ and $p_1=\frac{4(\alpha+1)}{2\alpha+1}$.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:00:43 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Kamel",
"Jamel El",
""
],
[
"Yacoub",
"Chokri",
""
]
] |
0706.3620 | Azita Mayeli | Ahmadreza Azimifard | Hypergroups with Unique Alpha-Means | 8 pages, keywords: Hypergroups: orthogonal polynomial, of Nevaei
classes. $\alpha$-Amenable Hypergroups | null | null | null | math.GR | null | Let $K$ be a commutative hypergroup and $\alpha\in \hat{K}$. We show that $K$
is $\alpha$-amenable with the unique $\alpha$-mean $m_\alpha$ if and only if
$m_\alpha\in L^1(K)\cap L^2(K)$ and $\alpha$ is isolated in $\hat{K}$. In
contrast to the case of amenable noncompact locally compact groups, examples of
polynomial hypergroups with unique $\alpha$-means ($\alpha\not=1$) are given.
Further examples emphasize that the $\alpha$-amenability of hypergroups depends
heavily on the asymptotic behavior of Haar measures and characters.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:05:31 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 13:29:53 GMT"
},
{
"version": "v3",
"created": "Thu, 17 Jan 2008 19:36:27 GMT"
}
] | 2008-01-17T00:00:00 | [
[
"Azimifard",
"Ahmadreza",
""
]
] |
0706.3621 | Gerald Marsh | Gerald E. Marsh | Climate Change: The Sun's Role | 16 pages, 8 figures, 1 table | null | null | null | physics.gen-ph | null | The sun's role in the earth's recent warming remains controversial even
though there is a good deal of evidence to support the thesis that solar
variations are a very significant factor in driving climate change both
currently and in the past. This precis lays out the background and data needed
to understand the basic scientific argument behind the contention that
variations in solar output have a significant impact on current changes in
climate. It also offers a simple, phenomenological approach for estimating the
actual-as opposed to model dependent-magnitude of the sun's influence on
climate.
| [
{
"version": "v1",
"created": "Sat, 23 Jun 2007 18:43:00 GMT"
}
] | 2010-07-29T00:00:00 | [
[
"Marsh",
"Gerald E.",
""
]
] |
0706.3622 | Hendrik Bartko | W. Wittek, H. Bartko, N. Galante, T. Schweizer | Comments on the Unified approach to the construction of Classical
confidence intervals | null | null | null | MPP-2007-78 | physics.data-an astro-ph | null | The paper comments on properties of the so-called "Unified approach to the
construction of classical confidence intervals", in which confidence intervals
are computed in a Neyman construction using the likelihood ratio as ordering
quantity. In particular, two of the main results of a paper by Feldman and
Cousins (F&C) are discussed. It is shown that in the case of central intervals
the so-called flip-flopping problem, occuring in the specific scenario where
the experimenter decides to quote a standard upper limit or a confidence
interval depending on the measurement, can be easily avoided by choosing
appropriate confidence levels for the standard upper limits and confidence
intervals. In the F&C paper "upper limit" is defined as the upper edge of a
confidence interval, whose lower edge coincides with the physical limit. With
this definition of upper limit (F&C limit), in an approach which uses the
likelihood ratio as ordering quantity, two-sided confidence intervals
automatically change over to "upper limits" as the signal becomes weaker
(Unified approach). In the present paper it is pointed out that this behaviour
is not a special property of this approach, because approaches with other
ordering principles, like central intervals, symmetric intervals or
highest-probability intervals, exhibit the same behaviour. The Unified approach
is presented in the F&C paper as a solution to the flip-flopping problem. This
might suggest that the F&C limit is a standard upper limit. In order to exclude
any misunderstanding, it is proposed in the present paper to call the F&C limit
"upper edge of the confidence interval", even if its lower edge coincides with
the physical limit.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:20:06 GMT"
},
{
"version": "v2",
"created": "Mon, 19 May 2008 10:28:38 GMT"
},
{
"version": "v3",
"created": "Mon, 26 May 2008 07:27:32 GMT"
}
] | 2008-05-26T00:00:00 | [
[
"Wittek",
"W.",
""
],
[
"Bartko",
"H.",
""
],
[
"Galante",
"N.",
""
],
[
"Schweizer",
"T.",
""
]
] |
0706.3623 | Sorin Popa | Narutaka Ozawa, Sorin Popa | On a class of $\mathrm{II}_1$ factors with at most one Cartan subalgebra | 27 pages; minor modifications; 10/27/07: New version with improved
statements, new applications, and simplifications in proofs | null | null | null | math.OA math.GR | null | We prove that the normalizer of any diffuse amenable subalgebra of a free
group factor $L(\Bbb F_r)$ generates an amenable von Neumann subalgebra.
Moreover, any II$_1$ factor of the form $Q \vt L(\Bbb F_r) $, with $Q$ an
arbitrary subfactor of a tensor product of free group factors, has no Cartan
subalgebras. We also prove that if a free ergodic measure preserving action of
a free group $\Bbb F_r$, $2\leq r \leq \infty$, on a probability space
$(X,\mu)$ is profinite then the group measure space factor $L^\infty(X)\rtimes
\Bbb F_r$ has unique Cartan subalgebra, up to unitary conjugacy.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:20:09 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 19:11:04 GMT"
},
{
"version": "v3",
"created": "Sun, 1 Jul 2007 20:27:58 GMT"
},
{
"version": "v4",
"created": "Sun, 28 Oct 2007 20:24:25 GMT"
}
] | 2007-10-30T00:00:00 | [
[
"Ozawa",
"Narutaka",
""
],
[
"Popa",
"Sorin",
""
]
] |
0706.3624 | Katia Ganda | Katia Ganda, Reynier F. Peletier, Richard M. McDermid, Jes\'us
Falc\'on-Barroso, P.T. de Zeeuw, Roland Bacon, Michele Cappellari, Roger L.
Davies, Eric Emsellem, Davor Krajnovi\'c, Harald Kuntschner, Marc Sarzi,
Glenn van de Ven | Absorption line-strengths of 18 late-type spiral galaxies observed with
SAURON | please find a high-resolution version at the following link:
http://www.strw.leidenuniv.nl/sauron/papers/ganda2007_late_types_LS.pdf ;
paper accepted for publication on MNRAS; 41 pages, 22 pictures | null | 10.1111/j.1365-2966.2007.12121.x | null | astro-ph | null | We present absorption line-strength maps for a sample of 18 Sb-Sd galaxies
observed using the integral-field spectrograph SAURON. The SAURON spectral
range allows the measurement of the Lick/IDS indices Hbeta, Fe5015 and Mgb,
which can be used to estimate the stellar population parameters. We present
here the two-dimensional line-strength maps for each galaxy. From the maps, we
learn that late-type spiral galaxies tend to have high Hbeta and low Fe5015 and
Mgb values, and that the Hbeta index has often a positive gradient over the
field, while the metal indices peak in the central region. We investigate the
relations between the central line-strength indices and their correlations with
morphological type and central velocity dispersion, and compare the observed
behaviour with that for ellipticals, lenticulars and early-type spirals from
the SAURON survey. We find that our galaxies lie below the Mg - sigma relation
determined for elliptical galaxies and that the indices show a clear trend with
morphological type. From the line-strength maps we calculate age, metallicity
and abundance ratio maps and discuss the results from a one-SSP approach and
from a two-SSP approach. Late-type galaxies are generally younger and more
metal poor than ellipticals and have abundance ratios closer to solar values.
We also explore a continuous star formation scenario, and try to recover the
star formation history using the evolutionary models of Bruzual & Charlot
(2003), assuming constant or exponentially declining star formation rate (SFR).
We find a correlation between the e-folding time-scale tau of the starburst and
the central velocity dispersion: more massive galaxies tend to have shorter
tau, suggesting that the star formation happened long ago and has now basically
ended, while for smaller objects with larger values of tau it is still active.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:22:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ganda",
"Katia",
""
],
[
"Peletier",
"Reynier F.",
""
],
[
"McDermid",
"Richard M.",
""
],
[
"Falcón-Barroso",
"Jesús",
""
],
[
"de Zeeuw",
"P. T.",
""
],
[
"Bacon",
"Roland",
""
],
[
"Cappellari",
"Michele",
""
],
[
"Davies",
"Roger L.",
""
],
[
"Emsellem",
"Eric",
""
],
[
"Krajnović",
"Davor",
""
],
[
"Kuntschner",
"Harald",
""
],
[
"Sarzi",
"Marc",
""
],
[
"van de Ven",
"Glenn",
""
]
] |
0706.3625 | Florian Marquardt | Ferdinand Helmer, Matteo Mariantoni, Austin G. Fowler, Jan von Delft,
Enrique Solano, Florian Marquardt | Two-dimensional cavity grid for scalable quantum computation with
superconducting circuits | version as published in EPL 95 No 5 (March 2009) 50007, 5 pages | EPL 85 No 5 (March 2009) 50007 (5pp) | 10.1209/0295-5075/85/50007 | null | cond-mat.mes-hall quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Superconducting circuits are among the leading contenders for quantum
information processing. This promising avenue has been strengthened with the
advent of circuit quantum electrodynamics, underlined by recent experiments
coupling on-chip microwave resonators to superconducting qubits. However,
moving towards more qubits will require suitable novel architectures. Here, we
propose a scalable setup for quantum computing where such resonators are
arranged in a two-dimensional grid with a qubit at each intersection. Its
versatility allows any two qubits on the grid to be coupled at a swapping
overhead independent of their distance and yields an optimal balance between
reducing qubit transition frequency spread and spurious cavity-induced
couplings. These features make this setup unique and distinct from existing
proposals in ion traps, optical lattices, or semiconductor spins. We
demonstrate that this approach encompasses the fundamental elements of a
scalable fault-tolerant quantum computing architecture.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:22:34 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Mar 2009 15:07:26 GMT"
}
] | 2009-03-24T00:00:00 | [
[
"Helmer",
"Ferdinand",
""
],
[
"Mariantoni",
"Matteo",
""
],
[
"Fowler",
"Austin G.",
""
],
[
"von Delft",
"Jan",
""
],
[
"Solano",
"Enrique",
""
],
[
"Marquardt",
"Florian",
""
]
] |
0706.3626 | Vladas Sidoravicius | Harry Kesten and Vladas Sidoravicius | A Problem in Last-Passage Percolation | 1 figure | null | null | null | math.PR math-ph math.MP | null | Let $\{X(v), v \in \Bbb Z^d \times \Bbb Z_+\}$ be an i.i.d. family of random
variables such that $P\{X(v)= e^b\}=1-P\{X(v)= 1\} = p$ for some $b>0$. We
consider paths $\pi \subset \Bbb Z^d \times \Bbb Z_+$ starting at the origin
and with the last coordinate increasing along the path, and of length $n$.
Define for such paths $W(\pi) = \text{number of vertices $\pi_i, 1 \le i \le
n$, with}X(\pi_i) = e^b$. Finally let $N_n(\al) = \text{number of paths $\pi$
of length $n$ starting at $\pi_0 = \bold 0$ and with $W(\pi) \ge \al n$.}$ We
establish several properties of $\lim_{n \to \infty} [N_n]^{1/n}$.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:24:50 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Kesten",
"Harry",
""
],
[
"Sidoravicius",
"Vladas",
""
]
] |
0706.3627 | Julien Roques | Anne Duval (LPP), Julien Roques (LEP) | Familles fuchsiennes d'\'equations aux (q-)diff\'erences et confluence | null | null | null | null | math.CA | null | In a first part, we give a method for solving a family of fuchsian systems of
operators of pseudo-derivations associated to a family of homographies with two
parameters which unify and generalize the differential, the difference and the
$q$-difference cases. In a second part, we study the problems of confluence
related to these families.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:46:11 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Duval",
"Anne",
"",
"LPP"
],
[
"Roques",
"Julien",
"",
"LEP"
]
] |
0706.3628 | Patricia Ball | Patricia Ball and G.W.Jones | B->eta(') Form Factors in QCD | 21 pages; version to appear in JHEP | JHEP 0708:025,2007 | 10.1088/1126-6708/2007/08/025 | IPPP/07/30 | hep-ph | null | We calculate the semileptonic form factors $f_+^{B\to \eta}(q^2)$ and
$f_+^{B\to \eta'}(q^2)$ from QCD sum rules on the light-cone (LCSRs), to NLO in
QCD, and for small to moderate q^2, $0\leq q^2\leq 16 {\rm
GeV}^2$. We include in particular the so-called singlet contribution, i.e.\
weak annihilation of the B meson with the emission of two gluons which, thanks
to the U(1)$_{\rm A}$ anomaly, couple directly to $\etap$. This effect is
included to leading-twist accuracy. This contribution has been neglected in
previous calculations of the form factors from LCSRs. We find that the singlet
contribution to $f_+^{B\to \eta'}$ can be up to 20%, while that to $f_+^{B\to
\eta}$ is, as expected, much smaller and below 3%. We also suggest to measure
the ratio ${\cal B}(B\to\eta' e \nu)/{\cal
B}(B\to \eta e \nu)$ to better constrain the size of the singlet
contribution.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:51:02 GMT"
},
{
"version": "v2",
"created": "Sun, 5 Aug 2007 07:13:29 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Ball",
"Patricia",
""
],
[
"Jones",
"G. W.",
""
]
] |
0706.3629 | Hiroki Ohta | Hiroki Ohta and Shin-ichi Sasa | Critical fluctuations of time-dependent magnetization in a random-field
Ising model | 5 pages, 7 figures | Phys. Rev. E, 77, 021119 (2008) | 10.1063/1.2897792 | null | cond-mat.stat-mech cond-mat.dis-nn | null | Cooperative behaviors near the disorder-induced critical point in a random
field Ising model are numerically investigated by analyzing time-dependent
magnetization in ordering processes from a special initial condition. We find
that the intensity of fluctuations of time-dependent magnetization, $\chi(t)$,
attains a maximum value at a time $t=\tau$ in a normal phase and that
$\chi(\tau)$ and $\tau$ exhibit divergences near the disorder-induced critical
point. Furthermore, spin configurations around the time $\tau$ are
characterized by a length scale, which also exhibits a divergence near the
critical point. We estimate the critical exponents that characterize these
power-law divergences by using a finite-size scaling method.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:53:19 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Mar 2008 20:52:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ohta",
"Hiroki",
""
],
[
"Sasa",
"Shin-ichi",
""
]
] |
0706.3630 | Thomas Ward | Richard Miles and Thomas Ward | Orbit-counting for nilpotent group shifts | null | Proc. Amer. Math. Soc. 137, 1499-1507 (2009) | 10.1090/S0002-9939-08-09649-4 | null | math.DS math.GR | null | We study the asymptotic behaviour of the orbit-counting function and a
dynamical Mertens' theorem for the full $G$-shift for a finitely-generated
torsion-free nilpotent group $G$. Using bounds for the M{\"o}bius function on
the lattice of subgroups of finite index and known subgroup growth estimates,
we find a single asymptotic of the shape \[ \sum_{|\tau|\le
N}\frac{1}{e^{h|\tau|}}\sim CN^{\alpha}(\log N)^{\beta} \] where $|\tau|$ is
the cardinality of the finite orbit $\tau$. For the usual orbit-counting
function we find upper and lower bounds together with numerical evidence to
suggest that for actions of non-cyclic groups there is no single asymptotic in
terms of elementary functions.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:54:29 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 10:17:29 GMT"
}
] | 2009-09-22T00:00:00 | [
[
"Miles",
"Richard",
""
],
[
"Ward",
"Thomas",
""
]
] |
0706.3631 | Pavel J\'achym | P. Jachym, J. Palous, J. Koppen, F. Combes | Gas stripping in galaxy clusters: a new SPH simulation approach | 18 pages, 23 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20066442 | null | astro-ph | null | The influence of a time-varying ram pressure on spiral galaxies in clusters
is explored with a new simulation method based on the N-body SPH/tree code
GADGET. We have adapted the code to describe the interaction of two different
gas phases, the diffuse hot intracluster medium (ICM) and the denser and colder
interstellar medium (ISM). Both the ICM and ISM components are introduced as
SPH particles. As a galaxy arrives on a highly radial orbit from outskirts to
cluster center, it crosses the ICM density peak and experiences a time-varying
wind. Depending on the duration and intensity of the ISM-ICM interaction, early
and late type galaxies in galaxy clusters with either a large or small ICM
distribution are found to show different stripping efficiencies, amounts of
reaccretion of the extra-planar ISM, and final masses. We compare the numerical
results with analytical approximations of different complexity and indicate the
limits of the Gunn & Gott simple stripping formula. Our investigations
emphasize the role of the galactic orbital history to the stripping amount. We
discuss the contribution of ram pressure stripping to the origin of the ICM and
its metallicity. We propose gas accumulations like tails, filaments, or ripples
to be responsible for stripping in regions with low overall ICM occurrence.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 12:56:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jachym",
"P.",
""
],
[
"Palous",
"J.",
""
],
[
"Koppen",
"J.",
""
],
[
"Combes",
"F.",
""
]
] |
0706.3632 | Andrea Miglio | Andrea Miglio (1), Josefina Montalban (1), Marc-Antoine Dupret (2)
((1) Universite de Liege, (2) Observatoire de Paris, LESIA) | Revised instability domains of SPB and beta Cephei stars | 9 pages, 4 figures. Accepted for publication in Communications in
Asteroseismology | null | 10.1553/cia151s48 | null | astro-ph | null | The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars
is known to be very sensitive to opacity changes in the stellar interior where
T~2 10^5 K. In this region differences in opacity up to ~50% can be induced by
the choice between OPAL and OP opacity tables, and between two different metal
mixtures (Grevesse and Noels 1993 and Asplund et al. 2005). We have extended
the non-adiabatic computations presented in Miglio et al. (2007) towards models
of higher mass and pulsation modes of degree l=3, and we present here the
instability domains in the HR- and log(P)-log(Teff) diagrams resulting from
different choices of opacity tables, and for three different metallicities.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:28:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Miglio",
"Andrea",
"",
"Universite de Liege"
],
[
"Montalban",
"Josefina",
"",
"Universite de Liege"
],
[
"Dupret",
"Marc-Antoine",
"",
"Observatoire de Paris, LESIA"
]
] |
0706.3633 | Subhashish Banerjee | Subhashish Banerjee and R. Srikanth | Phase Diffusion in Quantum Dissipative Systems | Accepted for publication in Physical Review A; changes in section V;
20 pages, 12 figures | null | 10.1103/PhysRevA.76.062109 | null | quant-ph cond-mat.stat-mech | null | We study the dynamics of the quantum phase distribution associated with the
reduced density matrix of a system for a number of situations of practical
importance, as the system evolves under the influence of its environment,
interacting via a quantum nondemoliton type of coupling, such that there is
decoherence without dissipation, as well as when it interacts via a dissipative
interaction, resulting in decoherence as well as dissipation. The system is
taken to be either a two-level atom (or equivalently, a spin-1/2 system) or a
harmonic oscillator, and the environment is modeled as a bath of harmonic
oscillators, starting out in a squeezed thermal state. The impact of the
different environmental parameters on the dynamics of the quantum phase
distribution for the system starting out in various initial states, is
explicitly brought out. An interesting feature that emerges from our work is
that the relationship between squeezing and temperature effects depends on the
type of system-bath interaction. In the case of quantum nondemolition type of
interaction, squeezing and temperature work in tandem, producing a diffusive
effect on the phase distribution. In contrast, in case of a dissipative
interaction, the influence of temperature can be counteracted by squeezing,
which manifests as a resistence to randomization of phase. We make use of the
phase distributions to bring out a notion of complementarity in atomic systems.
We also study the dispersion of the phase using the phase distributions
conditioned on particular initial states of the system.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:10:53 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Nov 2007 22:30:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Banerjee",
"Subhashish",
""
],
[
"Srikanth",
"R.",
""
]
] |
0706.3634 | Paul E. Gunnells | Avner Ash, Paul E. Gunnells, Mark McConnell | Cohomology of Congruence Subgroups of SL(4,\Z) II | null | null | null | null | math.NT | null | In a previous paper [3] we computed cohomology groups H^5 (Gamma_0 (N), \C),
where Gamma_0 (N) is a certain congruence subgroup of SL (4, \Z), for a range
of levels N. In this note we update this earlier work by extending the range of
levels and describe cuspidal cohomology classes and additional boundary
phenomena found since the publication of [3]. The cuspidal cohomology classes
in this paper are the first cuspforms for GL(4) concretely constructed in terms
of Betti cohomology.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:18:37 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Ash",
"Avner",
""
],
[
"Gunnells",
"Paul E.",
""
],
[
"McConnell",
"Mark",
""
]
] |
0706.3635 | Sean Sather-Wagstaff | Sean Sather-Wagstaff, Tirdad Sharif and Diana White | Comparison of relative cohomology theories with respect to semidualizing
modules | 28 pages | null | null | null | math.AC | null | We compare and contrast various relative cohomology theories that arise from
resolutions involving semidualizing modules. We prove a general balance result
for relative cohomology over a Cohen-Macaulay ring with a dualizing module, and
we demonstrate the failure of the naive version of balance one might expect for
these functors. We prove that the natural comparison morphisms between relative
cohomology modules are isomorphisms in several cases, and we provide a
Yoneda-type description of the first relative Ext functor. Finally, we show by
example that each distinct relative cohomology construction does in fact result
in a different functor.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:18:08 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Sather-Wagstaff",
"Sean",
""
],
[
"Sharif",
"Tirdad",
""
],
[
"White",
"Diana",
""
]
] |
0706.3636 | Mees de Roo | W.A. Chemissany, Mees de Roo, Sudhakar Panda | alpha'-Corrections to Heterotic Superstring Effective Action Revisited | 7 pages | JHEP0708:037,2007 | 10.1088/1126-6708/2007/08/037 | UG-07-04 | hep-th | null | In this letter we establish that the supersymmetric R^2 effective action for
the heterotic string, obtained from the supersymmetrisation of the Lorentz
Chern-Simons term, is to order $\alpha'$ equivalent modulo field redefinitions
to heterotic string effective actions computed by different methods.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:50:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chemissany",
"W. A.",
""
],
[
"de Roo",
"Mees",
""
],
[
"Panda",
"Sudhakar",
""
]
] |
0706.3637 | Thomas Richthammer | Thomas Richthammer | Translation-invariance of two-dimensional Gibbsian point processes | 44 pages, 6 figures | null | 10.1007/s00220-007-0274-7 | null | math.PR math-ph math.MP | null | The conservation of translation as a symmetry in two-dimensional systems with
interaction is a classical subject of statistical mechanics. Here we establish
such a result for Gibbsian particle systems with two-body interaction, where
the interesting cases of singular, hard-core and discontinuous interaction are
included. We start with the special case of pure hard core repulsion in order
to show how to treat hard cores in general.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:30:40 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Richthammer",
"Thomas",
""
]
] |
0706.3638 | Xiao-Wu Chen | Xiao-Wu Chen | Singularity categories, Schur Functors and Triangular Matrix Rings | Comments are welcome! | Algebra and Repre. Th. 12 (2009) 181-191. | null | null | math.RT math.RA | null | We study certain Schur functors which preserve singularity categories of
rings and we apply them to study the singularity category of triangular matrix
rings. In particular, combining these results with Buchweitz-Happel's theorem,
we can describe singularity categories of certain non-Gorenstein rings via the
stable category of maximal Cohen-Macaulay modules. Three concrete examples of
finite-dimensional algebras with the same singularity category are discussed.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:38:10 GMT"
}
] | 2010-02-18T00:00:00 | [
[
"Chen",
"Xiao-Wu",
""
]
] |
0706.3639 | Marcus Hutter | Shane Legg and Marcus Hutter | A Collection of Definitions of Intelligence | 12 LaTeX pages | Frontiers in Artificial Intelligence and Applications, Vol.157
(2007) 17-24 | null | IDSIA-07-07 | cs.AI | null | This paper is a survey of a large number of informal definitions of
``intelligence'' that the authors have collected over the years. Naturally,
compiling a complete list would be impossible as many definitions of
intelligence are buried deep inside articles and books. Nevertheless, the
70-odd definitions presented here are, to the authors' knowledge, the largest
and most well referenced collection there is.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:40:56 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Legg",
"Shane",
""
],
[
"Hutter",
"Marcus",
""
]
] |
0706.3640 | Robi Banerjee | Robi Banerjee, Ralf S. Klessen and Christian Fendt | Can Protostellar Jets Drive Supersonic Turbulence in Molecular Clouds? | 33 pages, 18 figures, accepted by ApJ, version with high resolution
figures at:
http://www.ita.uni-heidelberg.de/~banerjee/publications/jet_paper.pdf | null | 10.1086/521097 | null | astro-ph | null | Jets and outflows from young stellar objects are proposed candidates to drive
supersonic turbulence in molecular clouds. Here, we present the results from
multi-dimensional jet simulations where we investigate in detail the energy and
momentum deposition from jets into their surrounding environment and quantify
the character of the excited turbulence with velocity probability density
functions. Our study include jet--clump interaction, transient jets, and
magnetised jets. We find that collimated supersonic jets do not excite
supersonic motions far from the vicinity of the jet. Supersonic fluctuations
are damped quickly and do not spread into the parent cloud. Instead subsonic,
non-compressional modes occupy most of the excited volume. This is a generic
feature which can not be fully circumvented by overdense jets or magnetic
fields. Nevertheless, jets are able to leave strong imprints in their cloud
structure and can disrupt dense clumps. Our results question the ability of
collimated jets to sustain supersonic turbulence in molecular clouds.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:48:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Banerjee",
"Robi",
""
],
[
"Klessen",
"Ralf S.",
""
],
[
"Fendt",
"Christian",
""
]
] |
0706.3641 | Ralf Metzler | Tal Koren, Michael A. Lomholt, Aleksei V. Chechkin, Joseph Klafter,
Ralf Metzler | Leapover lengths and first passage time statistics for L\'evy flights | 4 pages, 5 figures, REVTeX | Phys. Rev. Lett. 99, 160602 (2007) | 10.1103/PhysRevLett.99.160602 | null | cond-mat.stat-mech | null | Exact results for the first passage time and leapover statistics of symmetric
and one-sided Levy flights (LFs) are derived. LFs with stable index alpha are
shown to have leapover lengths, that are asymptotically power-law distributed
with index alpha for one-sided LFs and, surprisingly, with index alpha/2 for
symmetric LFs. The first passage time distribution scales like a power-law with
index 1/2 as required by the Sparre Andersen theorem for symmetric LFs, whereas
one-sided LFs have a narrow distribution of first passage times. The exact
analytic results are confirmed by extensive simulations.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:05:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Koren",
"Tal",
""
],
[
"Lomholt",
"Michael A.",
""
],
[
"Chechkin",
"Aleksei V.",
""
],
[
"Klafter",
"Joseph",
""
],
[
"Metzler",
"Ralf",
""
]
] |
0706.3642 | Azita Mayeli | Daryl Geller, Azita Mayeli | Nearly Tight Frames and Space-Frequency Analysis on Compact Manifolds | 60 pages, 7 figures | null | null | null | math.CA math.FA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let $\bf M$ be a smooth compact oriented Riemannian manifold, and let
$\Delta$ be the Laplace-Beltrami operator on ${\bf M}$. Say $0 \neq f \in
\mathcal{S}(\RR^+)$, and that $f(0) = 0$. For $t > 0$, let $K_t(x,y)$ denote
the kernel of $f(t^2 \Delta)$. Suppose $f$ satisfies Daubechies' criterion, and
$b > 0$. For each $j$, write ${\bf M}$ as a disjoint union of measurable sets
$E_{j,k}$ with diameter at most $ba^j$, and comparable to $ba^j$ if $ba^j$ is
sufficiently small. Take $x_{j,k} \in E_{j,k}$. We then show that the functions
$\phi_{j,k}(x)=[\mu(E_{j,k})]^{1/2} \bar{K_{a^j}}(x_{j,k},x)$ form a frame for
$(I-P)L^2({\bf M})$, for $b$ sufficiently small (here $P$ is the projection
onto the constant functions). Moreover, we show that the ratio of the frame
bounds approaches 1 nearly quadratically as the dilation parameter approaches
1, so that the frame quickly becomes nearly tight (for $b$ sufficiently small).
Moreover, based upon how well-localized a function $F \in (I-P)L^2$ is in space
and in frequency, we can describe which terms in the summation $F \sim SF =
\sum_j \sum_k < F,\phi_{j,k} > \phi_{j,k}$ are so small that they can be
neglected. If $n=2$ and $\bf M$ is the torus or the sphere, and $f(s)=se^{-s}$
(the "Mexican hat" situation), we obtain two explicit approximate formulas for
the $\phi_{j,k}$, one to be used when $t$ is large, and one to be used when $t$
is small. Finally we explain in what sense the kernel $K_t(x,y)$ should itself
be regarded as a continuous wavelet on ${\bf M}$, and characterize the H\"older
continuous functions on ${\bf M}$ by the size of their continuous wavelet
transforms, for H\"older exponents strictly between 0 and 1.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:56:58 GMT"
},
{
"version": "v2",
"created": "Sun, 16 Sep 2007 13:43:07 GMT"
},
{
"version": "v3",
"created": "Thu, 27 Nov 2008 00:00:10 GMT"
}
] | 2008-11-28T00:00:00 | [
[
"Geller",
"Daryl",
""
],
[
"Mayeli",
"Azita",
""
]
] |
0706.3643 | SANGARA narayanan M V Dr | G. Nandhini and M.V.Sangaranarayanan | Partition function for two-dimensional nearest neighbour Ising model in
the presence of external magnetic field | 4 pages;one Figure; References added to the earlier version | null | null | null | physics.chem-ph | null | The partition function for two-dimensional nearest neighbour Ising models in
the presence of a magnetic field is derived . A comparison with the partition
functions predicted by Onsager is carried out. The critical temperature
estimated by two different methods yields good agreement with the result of
Yang and Lee.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:58:05 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 07:05:33 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Nandhini",
"G.",
""
],
[
"Sangaranarayanan",
"M. V.",
""
]
] |
0706.3644 | Marius Buliga | Marius Buliga | Dilatation structures with the Radon-Nikodym property | null | null | null | null | math.MG | null | In this paper I explain what is a pair of dilatation structures, one looking
down to another. Such a pair of dilatation structures leads to the intrinsic
definition of a distribution as a field of topological filters.
To any pair of dilatation structures there is an associated notion of
differentiability which generalizes the Pansu differentiability. This allows
the introduction of the Radon-Nikodym property for dilatation structures, which
is the straightforward generalization of the Radon-Nikodym property for Banach
spaces.
After an introducting section about length metric spaces and metric
derivatives, is proved that for a dilatation structure with the Radon-Nikodym
property the length of absolutely continuous curves expresses as an integral of
the norms of the tangents to the curve, as in Riemannian geometry.
Further it is shown that Radon-Nikodym property transfers from any "upper"
dilatation structure looking down to a "lower" dilatation structure, theorem
\ref{ttransfer}. Im my opinion this result explains intrinsically the fact that
absolutely continuous curves in regular sub-Riemannian manifolds are derivable
almost everywhere, as proved by Margulis-Mostow, Pansu (for Carnot groups) or
Vodopyanov.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:01:38 GMT"
}
] | 2007-06-28T00:00:00 | [
[
"Buliga",
"Marius",
""
]
] |
0706.3645 | Troels Harmark | Oscar J. C. Dias, Troels Harmark, Robert C. Myers, Niels A. Obers | Multi-black hole configurations on the cylinder | 42 pages, 4 figures. Minor comments added to match published version | Phys.Rev.D76:104025,2007 | 10.1103/PhysRevD.76.104025 | null | hep-th gr-qc | null | We construct the metric of new multi-black hole configurations on a
d-dimensional cylinder R^{d-1} x S^1, in the limit of small total mass (or
equivalently in the limit of a large cylinder). These solutions are valid to
first order in the total mass and describe configurations with several small
black holes located at different points along the circle direction of the
cylinder. We explain that a static configuration of black holes is required to
be in equilibrium such that the external force on each black hole is zero, and
we examine the resulting conditions. The first-order corrected thermodynamics
of the solutions is obtained and a Newtonian interpretation of it is given. We
then study the consequences of the multi-black hole configurations for the
phase structure of static Kaluza-Klein black holes and show that our new
solutions imply continuous non-uniqueness in the phase diagram. The new
multi-black hole configurations raise the question of existence of new
non-uniform black strings. Finally, a further analysis of the three-black hole
configuration suggests the possibility of a new class of static lumpy black
holes in Kaluza-Klein space.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:02:19 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 13:50:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dias",
"Oscar J. C.",
""
],
[
"Harmark",
"Troels",
""
],
[
"Myers",
"Robert C.",
""
],
[
"Obers",
"Niels A.",
""
]
] |
0706.3646 | Vladimir V. Kornyak | Vladimir V. Kornyak | Symmetries and Dynamics of Discrete Systems | 17 pages, 10 figures, [v2] includes additional material | CASC 2007, LNCS 4770, pp. 236--251, Springer 2007 | null | null | math-ph math.DS math.MP nlin.PS | null | We consider discrete dynamical systems and lattice models in statistical
mechanics from the point of view of their symmetry groups. We describe a C
program for symmetry analysis of discrete systems. Among other features, the
program constructs and investigates phase portraits of discrete dynamical
systems modulo groups of their symmetries, searches dynamical systems
possessing specific properties, e.g., reversibility, computes microcanonical
partition functions and searches phase transitions in mesoscopic systems. Some
computational results and observations are presented. In particular, we explain
formation of moving soliton-like structures similar to ``spaceships'' in
cellular automata.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:05:23 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 12:35:54 GMT"
}
] | 2007-10-08T00:00:00 | [
[
"Kornyak",
"Vladimir V.",
""
]
] |
0706.3647 | Vittoria Colizza | Vittoria Colizza, Alessandro Vespignani | Epidemic modeling in metapopulation systems with heterogeneous coupling
pattern: theory and simulations | 18 pages, 8 figures, minor corrections, inclusion of subleading terms | Journal of Theoretical Biology 251, 450-467 (2008) | null | null | q-bio.PE physics.soc-ph | null | The spatial structure of populations is a key element in the understanding of
the large scale spreading of epidemics. Motivated by the recent empirical
evidence on the heterogeneous properties of transportation and commuting
patterns among urban areas, we present a thorough analysis of the behavior of
infectious diseases in metapopulation models characterized by heterogeneous
connectivity and mobility patterns. We derive the basic reaction-diffusion
equation describing the metapopulation system at the mechanistic level and
derive an early stage dynamics approximation for the subpopulation invasion
dynamics. The analytical description uses degree block variables that allows us
to take into account arbitrary degree distribution of the metapopulation
network. We show that along with the usual single population epidemic threshold
the metapopulation network exhibits a global threshold for the subpopulation
invasion. We find an explicit analytic expression for the invasion threshold
that determines the minimum number of individuals traveling among
subpopulations in order to have the infection of a macroscopic number of
subpopulations. The invasion threshold is a function of factors such as the
basic reproductive number, the infectious period and the mobility process and
it is found to decrease for increasing network heterogeneity. We provide
extensive mechanistic numerical Monte Carlo simulations that recover the
analytical finding in a wide range of metapopulation network connectivity
patterns. The results can be useful in the understanding of recent data driven
computational approaches to disease spreading in large transportation networks
and the effect of containment measures such as travel restrictions.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:05:24 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 18:41:08 GMT"
}
] | 2008-03-19T00:00:00 | [
[
"Colizza",
"Vittoria",
""
],
[
"Vespignani",
"Alessandro",
""
]
] |
0706.3648 | Chuan Li | C. Li, Y. H. Tang, Y. Dai, C. Fang and J. -C. Vial | Flare magnetic reconnection and relativistic particles in the 2003
October 28 event | 5 pages, 7 figures, accepted by A&A | A&A, 472, 283, 2007 | 10.1051/0004-6361:20066966 | null | astro-ph | null | An X17.2 solar flare occurred on 2003 October 28, accompanied by
multi-wavelength emissions and a high flux of relativistic particles observed
at 1AU. We present the analytic results of the TRACE, SOHO, RHESSI, ACE, GOES,
hard X-ray (INTEGRAL satellite), radio (Onderejov radio telescope), and neutron
monitor data. It is found that the inferred magnetic reconnection electric
field correlates well with the hard X-ray, gamma-ray, and neutron emission at
the Sun. Thus the flare's magnetic reconnection probably makes a crucial
contribution to the prompt relativistic particles, which could be detected at 1
AU. Since the neutrons were emitted a few minutes before the injection of
protons and electrons, we propose a magnetic-field evolution configuration to
explain this delay. We do not exclude the effect of CME-driven shock, which
probably plays an important role in the delayed gradual phase of solar
energetic particles.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:50:08 GMT"
}
] | 2013-05-24T00:00:00 | [
[
"Li",
"C.",
""
],
[
"Tang",
"Y. H.",
""
],
[
"Dai",
"Y.",
""
],
[
"Fang",
"C.",
""
],
[
"Vial",
"J. -C.",
""
]
] |
0706.3649 | Yifu Zhu | Gessler Hernandez, Jiepeng Zhang, and Yifu Zhu | Vacuum Rabi splitting and intracavity dark state in a cavity-atoms
system | 11 pages, 4 figures | null | 10.1103/PhysRevA.76.053814 | null | physics.optics physics.atom-ph | null | We report experimental measurements of the transmission spectrum of an
optical cavity coupled with cold Rb atoms. We observe the multi-atom vacuum
Rabi splitting of a composite cavity and atom system. When a coupling field is
applied to the atoms and induces the resonant two-photon Raman transition with
the cavity field in a Lamda-type three-level system, we observe a cavity
transmission spectrum with two vacuum Rabi sidebands and a central peak
representing the intracavity dark state. The central peak linewidth is
significantly narrowed by the dark-state resonance and its position is
insensitive to the frequency change of the empty cavity.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:10:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hernandez",
"Gessler",
""
],
[
"Zhang",
"Jiepeng",
""
],
[
"Zhu",
"Yifu",
""
]
] |
0706.3650 | Jan Govaerts | Jan Govaerts (1,2) and Frederik G. Scholtz (1) ((1) Institute of
Theoretical Physics, Department of Physics, University of Stellenbosch,
Stellenbosch, Republic of South Africa, (2) UNESCO International Chair in
Mathematical Physics and Applications (UNESCO-ICMPA), Cotonou, Republic of
Benin) | The Weyl-Heisenberg Group on the Noncommutative Two-Torus: A Zoo of
Representations | 24 pages, no figures | J.Phys.A40:12415-12438,2007 | 10.1088/1751-8113/40/41/011 | CP3-07-18, ICMPA-MPA/2007/17 | hep-th | null | In order to assess possible observable effects of noncommutativity in
deformations of quantum mechanics, all irreducible representations of the
noncommutative Heisenberg algebra and Weyl-Heisenberg group on the two-torus
are constructed. This analysis extends the well known situation for the
noncommutative torus based on the algebra of the noncommuting position
operators only. When considering the dynamics of a free particle for any of the
identified representations, no observable effect of noncommutativity is
implied.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:20:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Govaerts",
"Jan",
""
],
[
"Scholtz",
"Frederik G.",
""
]
] |
0706.3651 | Toshimitsu Yamazaki | Toshimitsu Yamazaki and Yoshinori Akaishi | Super strong nuclear force caused by migrating Kbar mesons - Revival of
the Heitler-London-Heisenberg scheme in kaonic nuclear clusters | 11 pages, 5 figures | Proc.JapanAcad.B83:144,2007 | 10.2183/pjab.83.144 | null | nucl-th | null | We have studied the structure of K- pp comprehensively by solving this
three-body system in a variational method, starting from the Ansatz that the
Lambda(1405) resonance (~ Lambda*) is a K-p bound state. The structure of K-pp
reveals a molecular feature, namely, the K- in Lambda* as an "atomic center"
plays a key role in producing strong covalent bonding with the other proton. We
point out that strongly bound Kbar nuclear systems are formed by ``super
strong" nuclear force due to migrating real bosonic particles Kbar a la
Heitler-London-Heisenberg, whereas the normal nuclear force is caused by
mediating virtual pions. We have shown that the elementary process, p + p -->
K+ + Lambda* + p, which occurs in a short impact parameter and with a large
momentum transfer, leads to unusually large self-trapping of Lambda* by the
involved proton, since the Lambda*-p system exists as a compact doorway state
propagating to K-pp.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 13:59:47 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 12:18:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yamazaki",
"Toshimitsu",
""
],
[
"Akaishi",
"Yoshinori",
""
]
] |
0706.3652 | Eric Lauga | Eric Lauga | Continuous breakdown of Purcell's scallop theorem with inertia | 6 pages, 1 figure | Phys. Fluids 19, 061703, 2007 | 10.1063/1.2738609 | null | cond-mat.soft physics.bio-ph physics.flu-dyn | null | Purcell's scallop theorem defines the type of motions of a solid body -
reciprocal motions - which cannot propel the body in a viscous fluid with zero
Reynolds number. For example, the flapping of a wing is reciprocal and, as was
recently shown, can lead to directed motion only if its frequency Reynolds
number, Re_f, is above a critical value of order one. Using elementary
examples, we show the existence of oscillatory reciprocal motions which are
effective for all arbitrarily small values of the frequency Reynolds number and
induce net velocities scaling as (Re_f)^\alpha (alpha > 0). This demonstrates a
continuous breakdown of the scallop theorem with inertia.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:25:49 GMT"
}
] | 2008-10-02T00:00:00 | [
[
"Lauga",
"Eric",
""
]
] |
0706.3653 | Pulak Ranjan Giri | Pulak Ranjan Giri | Lower bound of minimal time evolution in quantum mechanics | 4 pages, no figure, revtex4 | Int.J.Theor.Phys.47:2095-2100,2008 | 10.1007/s10773-008-9650-0 | SINP/TNP/2007/39 | quant-ph hep-th | null | We show that the total time of evolution from the initial quantum state to
final quantum state and then back to the initial state, i.e., making a round
trip along the great circle over S^2, must have a lower bound in quantum
mechanics, if the difference between two eigenstates of the 2\times 2
Hamiltonian is kept fixed. Even the non-hermitian quantum mechanics can not
reduce it to arbitrarily small value. In fact, we show that whether one uses a
hermitian Hamiltonian or a non-hermitian, the required minimal total time of
evolution is same. It is argued that in hermitian quantum mechanics the
condition for minimal time evolution can be understood as a constraint coming
from the orthogonality of the polarization vector \bf P of the evolving quantum
state \rho={1/2}(\bf 1+ \bf{P}\cdot\boldsymbol{\sigma}) with the vector
\boldsymbol{\mathcal O}(\Theta) of the 2\times 2 hermitian Hamiltonians H
={1/2}({\mathcal O}_0\boldsymbol{1}+ \boldsymbol{\mathcal
O}(\Theta)\cdot\boldsymbol{\sigma}) and it is shown that the Hamiltonian H can
be parameterized by two independent parameters {\mathcal O}_0 and \Theta.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:28:23 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jan 2008 09:24:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Giri",
"Pulak Ranjan",
""
]
] |
0706.3654 | Sadi Turgut | S. Turgut | Catalytic Conversion Probabilities for Bipartite Pure States | 4 pages; comments appreciated; the article is a modified version of
this preprint combined with arXiv:0707.0444 | J. Phys. A: Math. Theor. 40 (2007) 12185-12212 | 10.1088/1751-8113/40/40/012 | null | quant-ph | null | For two given bipartite-entangled pure states, an expression is obtained for
the least upper bound of conversion probabilities using catalysis. The
attainability of the upper bound can also be decided if that bound is less than
one.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:44:15 GMT"
}
] | 2007-09-19T00:00:00 | [
[
"Turgut",
"S.",
""
]
] |
0706.3655 | Nicholas Ouellette | Nicholas T. Ouellette and J. P. Gollub | Curvature Fields, Topology, and the Dynamics of Spatiotemporal Chaos | 5 pages, 5 figures | null | 10.1103/PhysRevLett.99.194502 | null | physics.flu-dyn | null | The curvature field is measured from tracer particle trajectories in a
two-dimensional fluid flow that exhibits spatiotemporal chaos, and is used to
extract the hyperbolic and elliptic points of the flow. These special points
are pinned to the forcing when the driving is weak, but wander over the domain
and interact in pairs at stronger driving, changing the local topology of the
flow. Their behavior reveals a two-stage transition to spatiotemporal chaos: a
gradual loss of spatial and temporal order followed by an abrupt onset of
topological changes.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:33:56 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 18:47:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ouellette",
"Nicholas T.",
""
],
[
"Gollub",
"J. P.",
""
]
] |
0706.3656 | Lucas Fresse | Lucas Fresse | Betti numbers of Springer fibers in type A | 17 pages | J. Algebra 322 (2009) 2566-2579 | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We determine the Betti numbers of the Springer fibers in type A. To do this,
we construct a cell decomposition of the Springer fibers. The codimension of
the cells is given by an analogue of the Coxeter length. This makes our cell
decomposition well suited for the calculation of Betti numbers.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:34:55 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Mar 2009 20:57:20 GMT"
}
] | 2009-12-08T00:00:00 | [
[
"Fresse",
"Lucas",
""
]
] |
0706.3657 | Edward Swartz | Patricia Hersh, Ed Swartz | Coloring complexes and arrangements | 11 pages. To appear in the Journal of Algebraic Combinatorics | null | null | null | math.CO | null | Steingrimsson's coloring complex and Jonsson's unipolar complex are
interpreted in terms of hyperplane arrangements. This viewpoint leads to short
proofs that all coloring complexes and a large class of unipolar complexes have
convex ear decompositions. These convex ear decompositions impose strong new
restrictions on the chromatic polynomials of all finite graphs. Similar results
are obtained for characteristic polynomials of submatroids of type B_n
arrangements.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:38:16 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Hersh",
"Patricia",
""
],
[
"Swartz",
"Ed",
""
]
] |
0706.3658 | Jerzy Kowalski-Glikman | L. Freidel, J. Kowalski-Glikman and S. Nowak | Field theory on $\kappa$--Minkowski space revisited: Noether charges and
breaking of Lorentz symmetry | 22 pages, 1 figure, formulas in sect. III corrected | Int.J.Mod.Phys.A23:2687-2718,2008 | 10.1142/S0217751X08040421 | null | hep-th | null | This paper is devoted to detailed investigations of free scalar field theory
on $\kappa$-Minkowski space. After reviewing necessary mathematical tools we
discuss in depth the Lagrangian and solutions of field equations. We analyze
the spacetime symmetries of the model and construct the conserved charges
associated with translational and Lorentz symmetry. We show that the version of
the theory usually studied breaks Lorentz invariance in a subtle way: There is
an additional trans-Planckian mode present, and an associated conserved charge
(the number of such modes) is not a Lorentz scalar.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:39:17 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 09:46:25 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Freidel",
"L.",
""
],
[
"Kowalski-Glikman",
"J.",
""
],
[
"Nowak",
"S.",
""
]
] |
0706.3659 | Peter West | Fabio Riccioni, Duncan Steele and Peter West | Duality Symmetries and G^{+++} Theories | 35 pages. v2: 2 appendices added, other minor corrections. v3: tables
corrected, other minor changes, one appendix added, refs. added. Version
published in Class. Quant. Grav | Class.Quant.Grav.25:045012,2008 | 10.1088/0264-9381/25/4/045012 | KCL-MTH-07-09 | hep-th | null | We show that the non-linear realisations of all the very extended algebras
G^{+++}, except the B and C series which we do not consider, contain fields
corresponding to all possible duality symmetries of the on-shell degrees of
freedom of these theories. This result also holds for G_2^{+++} and we argue
that the non-linear realisation of this algebra accounts precisely for the form
fields present in the corresponding supersymmetric theory. We also find a
simple necessary condition for the roots to belong to a G^{+++} algebra.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:43:08 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 16:00:04 GMT"
},
{
"version": "v3",
"created": "Tue, 26 Feb 2008 10:55:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Riccioni",
"Fabio",
""
],
[
"Steele",
"Duncan",
""
],
[
"West",
"Peter",
""
]
] |
0706.3660 | Jurgen Engelfried | SELEX Collaboration, J.L.Sanchez-Lopez, K.D.Nelson, J.Engelfried, et
al | Polarization of Lambda0 and antiLambda0 inclusively produced by 610GeV/c
Sigma- and 525GeV/c proton beams | 6 pages, 5 figures, submitted to PRD | null | null | UASLP-IF-07-003, FERMILAB-Pub-07-312-E | hep-ex | null | We have measured the polarization of Lambda0 and antiLambda0 inclusively
produced by 610GeV/c Sigma- and 525GeV/c proton beams in the experiment SELEX
during the 1996/7 fixed target run at Fermilab. The polarization was measured
as a function of the Lambda longitudinal momentum fraction xF and transverse
momentum pt. For the Lambda0 produced by Sigma- the polarization is increasing
with xF, from slightly negative at x_F~0 to about 15% at large xF; it shows a
non-monotonic behavior as a function of pt. For the proton beam, the Lambda0
polarization is negative and decreasing as a function of xF and pt. The
antiLambda0 polarization is compatible with 0 for both beam particles over the
full kinematic range. The target dependence was examined but no statistically
significant difference was found.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 14:55:13 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"SELEX Collaboration",
"",
""
],
[
"Sanchez-Lopez",
"J. L.",
""
],
[
"Nelson",
"K. D.",
""
],
[
"Engelfried",
"J.",
""
]
] |
0706.3661 | Malay Bandyopadhyay Dr. | Malay Bandyopadhyay | Thermodynamic properties of magneto-anisotropic nanoparticles | This paper is withdrawn, because it is a older version and the newer
version can be found in J. Phys.: Condens. Matter 21, 23600 (2009) | null | null | null | cond-mat.stat-mech | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The purpose of this paper is to study the thermodynamic equilibrium
properties of a collection of non-interacting three-dimensional (3D)
magnetically anisotropic nanoparticles in the light of classical statistical
physics. Pertaining to the angular dependence ($\alpha$) of the magnetic field
with the anisotropy axis, energy landscape plots are obtained which reveal a
continuous transition from a double well to a single well for
$\alpha=\frac{\pi}{2}$ and show asymmetric bistable shape for other values of
$\alpha$. The present analysis is related with the interpretation of
equilibrium magnetization and static susceptibility of nanomagnetic system as a
function of external magnetic field, $B$, and temperature, $T$. The
magnetization and susceptibility confirms the non Langevin behaviour of
magneto-anisotropic monodomain particles. The susceptibility analysis
establishes the ferromagnetic, antiferromagnetic and paramagnetic like coupling
for various $\alpha$. This study reveals the essential role of magneto
anisotropic energy in the interpretation of the magnetic behaviour of a
collection of noninteracting single domain nanoparticles.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:01:09 GMT"
},
{
"version": "v2",
"created": "Wed, 13 May 2009 05:11:13 GMT"
},
{
"version": "v3",
"created": "Sat, 17 Dec 2011 17:27:40 GMT"
}
] | 2011-12-20T00:00:00 | [
[
"Bandyopadhyay",
"Malay",
""
]
] |
0706.3662 | Horace Stoica | Arttu Rajantie, Mairi Sakellariadou and Horace Stoica | Numerical experiments with p F- and q D-strings: the formation of (p,q)
bound states | 17 pages, 8 figures, JCAP style | JCAP0711:021,2007 | 10.1088/1475-7516/2007/11/021 | Imperial/TP/07/AR/01 | hep-th astro-ph hep-ph | null | We investigate the behaviour of (p,q) string networks, focusing on two
aspects: (1) modelling more realistic (p,q) string networks than the Z_N
networks used so far and (2) investigating the effect of long-range
interactions on the evolution of the network. We model the network with no
long-range interactions using two sets of fields, complex scalars coupled to
gauge fields, with a potential chosen such that the two types of strings will
form bound states. This way we can model junctions of 3 strings with different
tension; in Z_N models used so far in simulations all the strings have
identical tensions. In order to introduce long-range interactions we also study
a network in which one of the scalars forms global strings. We observe that in
the absence of long-range interactions the formation of bound states has a
significant influence on the evolution of the network. When long-range
interactions are turned on the bound states are short-lived and have a minimal
effect on the network evolution.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:01:47 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 10:24:27 GMT"
},
{
"version": "v3",
"created": "Fri, 7 Dec 2007 15:05:49 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Rajantie",
"Arttu",
""
],
[
"Sakellariadou",
"Mairi",
""
],
[
"Stoica",
"Horace",
""
]
] |
0706.3663 | Wung-Hong Huang | Wung-Hong Huang | Wilson-t'Hooft Loops in Finite-Temperature Non-commutative Dipole Field
Theory from Dual Supergravity | Latex, 22 pages, 8 figures, add several comments | Phys.Rev.D76:106005,2007 | 10.1103/PhysRevD.76.106005 | null | hep-th | null | We first study the temporal Wilson loop in the finite-temperature
non-commutative dipole field theory from the string/gauge correspondence. The
associated dual supergravity background is constructed from the near-horizon
geometry of near-extremal D-branes, after applying T-duality and smeared twist.
We investigate the string configuration therein and find that while the
temperature produces a maximum distance $L_{max}$ in the interquark distance
the dipole in there could produce a minimum distance $L_{min}$. The quark
boundary pair therefore could be found only if their distance is between
$L_{min}$ and $L_{max}$. We also show that, beyond a critical temperature the
quark pair becomes totally free due to screening by thermal bath. We next study
the spatial Wilson loop and find the confining nature in the zero temperature
3D and 4D non-supersymmetry dipole gauge theory. The string tension of the
linear confinement potential is obtained and found to be a decreasing function
of the dipole field. We also investigate the associated t'Hooft loop and
determine the corresponding monopole anti-monopole potential. The conventional
screening of magnetic charge which indicates the confinement of the electric
charge is replaced by a strong repulsive however. Finally, we show that the
dual string which is rotating along the dipole deformed $S^5$ will behave as a
static one without dipole field, which has no minimum distance and has larger
energy than a static one with dipole field. We discuss the phase transition
between these string solutions.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:02:51 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 11:27:19 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Sep 2007 13:49:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Huang",
"Wung-Hong",
""
]
] |
0706.3664 | Alessandro Campa | Alessandro Campa, Andrea Giansanti, Gianluca Morelli | Long time behavior of quasi-stationary states of the Hamiltonian
Mean-Field model | Submitted to Phys. Rev. E | null | 10.1103/PhysRevE.76.041117 | null | cond-mat.stat-mech | null | The Hamiltonian Mean-Field model has been investigated, since its
introduction about a decade ago, to study the equilibrium and dynamical
properties of long-range interacting systems. Here we study the long-time
behavior of long-lived, out-of-equilibrium, quasi-stationary dynamical states,
whose lifetime diverges in the thermodynamic limit. The nature of these states
has been the object of a lively debate, in the recent past. We introduce a new
numerical tool, based on the fluctuations of the phase of the instantaneous
magnetization of the system. Using this tool, we study the quasi-stationary
states that arise when the system is started from different classes of initial
conditions, showing that the new observable can be exploited to compute the
lifetime of these states. We also show that quasi-stationary states are present
not only below, but also above the critical temperature of the second order
magnetic phase transition of the model. We find that at supercritical
temperatures the lifetime is much larger than at subcritical temperatures.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:13:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Campa",
"Alessandro",
""
],
[
"Giansanti",
"Andrea",
""
],
[
"Morelli",
"Gianluca",
""
]
] |
0706.3665 | David Montes | M.C. G\'alvez (1 and 2), D. Montes (1), M.J. Fern\'andez-Figueroa (1),
E. De Castro (1), M. Cornide (1) ((1) Dept. Astrof\'isica, UCM, Universidad
Complutense de Madrid, Spain, (2) Department of Astronomy, University of
Florida, USA) | Multiwavelength optical observations of chromospherically active binary
systems V. FF UMa (2RE J0933+624): a system with orbital period variation | Latex file with 16 pages, 18 figures. Available at
http://www.ucm.es/info/Astrof/invest/actividad/actividad_pub.html Accepted
for publication in: Astronomy & Astrophysics (A&A) | null | 10.1051/0004-6361:20067015 | null | astro-ph | null | This is the fifth paper in a series aimed at studying the chromospheres of
active binary systems using several optical spectroscopic indicators to obtain
or improve orbital solution and fundamental stellar parameters. We present here
the study of FF UMa (2RE J0933+624), a recently discovered, X-ray/EUV selected,
active binary with strong H_alpha emission. The objectives of this work are, to
find orbital solutions and define stellar parameters from precise radial
velocities and carry out an extensive study of the optical indicators of
chromospheric activity. We obtained high resolution echelle spectroscopic
observations during five observing runs from 1998 to 2004. We found radial
velocities by cross correlation with radial velocity standard stars to achieve
the best orbital solution. We also measured rotational velocity by
cross-correlation techniques and have studied the kinematic by galactic space-
velocity components (U, V, W) and Eggen criteria. Finally, we have determined
the chromospheric contribution in optical spectroscopic indicators, from Ca II
H & K to Ca II IRT lines, using the spectral subtraction technique. We have
found that this system presents an orbital period variation, higher than
previously detected in other RS CVn systems. We determined an improved orbital
solution, finding a circular orbit with a period of 3.274 days. We derived the
stellar parameters, confirming the subgiant nature of the primary component and
obtained rotational velocities (vsini), of 33.57 km/s and 32.38 km/s for the
primary and secondary components respectively. From our kinematic study, we can
deduce its membership to the Castor moving group. Finally, the activity study
has given us a better understanding of the possible mechanisms that produce the
orbital period variation.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:47:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gálvez",
"M. C.",
"",
"1 and 2"
],
[
"Montes",
"D.",
""
],
[
"Fernández-Figueroa",
"M. J.",
""
],
[
"De Castro",
"E.",
""
],
[
"Cornide",
"M.",
""
]
] |
0706.3666 | Hajime Takami | Hajime Takami (1), Katsuhiko Sato (1,2); ((1) University of Tokyo, (2)
Research Center for the Early Universe, University of Tokyo) | Propagation of Ultra-high-energy Protons in Cosmic Magnetic Fields | Contribution to the 30th International Cosmic Ray Conference, Merida
Mexico, July 2007, a corrected version; 4 pages, 3 figures | null | null | null | astro-ph | null | We simulate the arrival distribution of ultra-high-energy (UHE) protons by
following their propagation processes in several strengths of a structured
extragalactic magnetic field (EGMF). Comparing our result to observational one
by Akeno Giant Air Shower Array, we constrain the number density of UHE cosmic
ray sources with the small-scale anisotropy. As a result, the source number
density is $\sim 10^{-5} {\rm Mpc}^{-3}$ with uncertainty of about an order of
magnitude due to the small number of observed events. This hardly depends on
our structured EGMF strength. We also investigate future prospects for this
approarch. The near future observations, such as Pierre Auger Observatory, can
distinguish $10^{-6} {\rm Mpc}^{-3}$ accurately from the more source densities.
Number of events to discriminate between $10^{-4}$ and $10^{-5} {\rm Mpc}^{-3}$
is dependent on the EGMF strength.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:39:48 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Takami",
"Hajime",
""
],
[
"Sato",
"Katsuhiko",
""
],
[
";",
"",
""
]
] |
0706.3667 | Claudia Quercellini | Claudia Quercellini (1), Marco Bruni (1, 2 and 3) and Amedeo Balbi (1
and 2) ((1) Universita' di Roma Tor Vergata, (2) INFN Sezione di Roma Tor
Vergata, (3) University of Portsmouth) | Affine equation of state from quintessence and k-essence fields | 9 pages, 6 figures. Minor updates, accepted by CQG | Class.Quant.Grav.24:5413-5426,2007 | 10.1088/0264-9381/24/22/006 | null | astro-ph gr-qc hep-th | null | We explore the possibility that a scalar field with appropriate Lagrangian
can mimic a perfect fluid with an affine barotropic equation of state. The
latter can be thought of as a generic cosmological dark component evolving as
an effective cosmological constant plus a generalized dark matter. As such, it
can be used as a simple, phenomenological model for either dark energy or
unified dark matter. Furthermore, it can approximate (up to first order in the
energy density) any barotropic dark fluid with arbitrary equation of state. We
find that two kinds of Lagrangian for the scalar field can reproduce the
desired behaviour: a quintessence-like with a hyperbolic potential, or a purely
kinetic k-essence one. We discuss the behaviour of these two classes of models
from the point of view of the cosmological background, and we give some hints
on their possible clustering properties.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:13:45 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 14:04:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Quercellini",
"Claudia",
"",
"1, 2 and 3"
],
[
"Bruni",
"Marco",
"",
"1, 2 and 3"
],
[
"Balbi",
"Amedeo",
"",
"1\n and 2"
]
] |
0706.3668 | Scott T. Kay | Scott T. Kay, Leila C. Powell, Andrew R. Liddle, Peter A. Thomas | The Sunyaev-Zel'dovich temperature of the intracluster medium | This version accepted for publication in MNRAS following minor
revision | null | 10.1111/j.1365-2966.2008.13183.x | null | astro-ph | null | The relativistic Sunyaev-Zel'dovich (SZ) effect offers a method, independent
of X-ray, for measuring the temperature of the intracluster medium (ICM) in the
hottest systems. Here, using N-body/hydrodynamic simulations of three galaxy
clusters, we compare the two quantities for a non-radiative ICM, and for one
that is subject both to radiative cooling and strong energy feedback from
galaxies. Our study has yielded two interesting results. Firstly, in all cases,
the SZ temperature is hotter than the X-ray temperature and is within ten per
cent of the virial temperature of the cluster. Secondly, the mean SZ
temperature is less affected by cooling and feedback than the X-ray
temperature. Both these results can be explained by the SZ temperature being
less sensitive to the distribution of cool gas associated with cluster
substructure. A comparison of the SZ and X-ray temperatures (measured for a
sample of hot clusters) would therefore yield interesting constraints on the
thermodynamic structure of the intracluster gas.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 15:58:48 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Mar 2008 09:26:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kay",
"Scott T.",
""
],
[
"Powell",
"Leila C.",
""
],
[
"Liddle",
"Andrew R.",
""
],
[
"Thomas",
"Peter A.",
""
]
] |
0706.3669 | Andras Vasy | Andras Vasy | The wave equation on asymptotically de Sitter-like spaces | 40 pages, 1 figure | null | null | null | math.AP math.DG | null | In this paper we obtain the asymptotic behavior of solutions of the
Klein-Gordon equation on Lorentzian manifolds $(X^\circ,g)$ which are de
Sitter-like at infinity. Such manifolds are Lorentzian analogues of the
so-called Riemannian conformally compact (or asymptotically hyperbolic) spaces.
Under global assumptions on the (null)bicharacteristic flow, namely that the
boundary of the compactification X is a union of two disjoint manifolds, Y+ and
Y-, and each bicharacteristic converges to one of these two manifolds as the
parameter along the bicharacteristic goes to plus infinity, and to the other
manifold as the parameter goes to minus infinity, we also define the scattering
operator, and show that it is a Fourier integral operator associated to the
bicharacteristic flow from Y+ to Y-.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:32:15 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Vasy",
"Andras",
""
]
] |
0706.3670 | Richard Hill | Richard Hill | Construction of eigenvarieties in small cohomological dimensions for
semi-simple, simply connected groups | null | null | null | null | math.NT | null | We study low order terms of Emerton's spectral sequence for simply connected,
simple groups. As a result, for real rank 1 groups, we show that Emerton's
method for constructing eigenvarieties is successful in cohomological dimension
1. For real rank 2 groups, we show that a slight modification of Emerton's
method allows one to construct eigenvarieties in cohomological dimension 2.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:39:55 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Hill",
"Richard",
""
]
] |
0706.3671 | M. Cristina Depassier | R. D. Benguria, M. C. Depassier, M. Loss | Validity of the Brunet-Derrida formula for the speed of pulled fronts
with a cutoff | 8 pages, 3 figures | European Physical Journal B 61 (2008) 331 | 10.1140/epjb/e2008-00069-1 | null | nlin.PS | null | We establish rigorous upper and lower bounds for the speed of pulled fronts
with a cutoff. We show that the Brunet-Derrida formula corresponds to the
leading order expansion in the cut-off parameter of both the upper and lower
bounds. For sufficiently large cut-off parameter the Brunet-Derrida formula
lies outside the allowed band determined from the bounds. If nonlinearities are
neglected the upper and lower bounds coincide and are the exact linear speed
for all values of the cut-off parameter.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:43:20 GMT"
}
] | 2015-04-28T00:00:00 | [
[
"Benguria",
"R. D.",
""
],
[
"Depassier",
"M. C.",
""
],
[
"Loss",
"M.",
""
]
] |
0706.3672 | Kirill Semenov-Tian-Shansky | Kirill M.Semenov-Tian-Shansky, Alexander V.Vereshagin, Vladimir V.
Vereshagin | Bootstrap and the physical values of $\pi N$ resonance parameters | 41 pages, 7 figures | Phys.Rev.D77:025028,2008 | 10.1103/PhysRevD.77.025028 | null | hep-ph hep-th | null | This is the 6th paper in the series developing the formalism to manage the
effective scattering theory of strong interactions. Relying on the theoretical
scheme suggested in our previous publications we concentrate here on the
practical aspect and apply our technique to the elastic pion-nucleon scattering
amplitude. We test numerically the pion-nucleon spectrum sum rules that follow
from the tree level bootstrap constraints. We show how these constraints can be
used to estimate the tensor and vector $NN\rho$ coupling constants. At last, we
demonstrate that the tree-level low energy expansion coefficients computed in
the framework of our approach show nice agreement with known experimental data.
These results allow us to claim that the extended perturbation scheme is quite
reasonable from the computational point of view.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:13:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Semenov-Tian-Shansky",
"Kirill M.",
""
],
[
"Vereshagin",
"Alexander V.",
""
],
[
"Vereshagin",
"Vladimir V.",
""
]
] |
0706.3673 | Thomas Auer | T. Berstermann, T. Auer, H. Kurtze, M. Schwab, D.R. Yakovlev, M.
Bayer, J. Wiersig, C. Gies, F. Jahnke, D. Reuter, A.D. Wieck | Systematic study of carrier correlations in the electron-hole
recombination dynamics of quantum dots | 8 pages, 7 figures | null | 10.1103/PhysRevB.76.165318 | null | cond-mat.other | null | The ground state carrier dynamics in self-assembled (In,Ga)As/GaAs quantum
dots has been studied using time-resolved photoluminescence and transmission.
By varying the dot design with respect to confinement and doping, the dynamics
is shown to follow in general a non-exponential decay. Only for specific
conditions in regard to optical excitation and carrier population, for example,
the decay can be well described by a mono-exponential form. For resonant
excitation of the ground state transition a strong shortening of the
luminescence decay time is observed as compared to the non-resonant case. The
results are consistent with a microscopic theory that accounts for deviations
from a simple two-level picture.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:00:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Berstermann",
"T.",
""
],
[
"Auer",
"T.",
""
],
[
"Kurtze",
"H.",
""
],
[
"Schwab",
"M.",
""
],
[
"Yakovlev",
"D. R.",
""
],
[
"Bayer",
"M.",
""
],
[
"Wiersig",
"J.",
""
],
[
"Gies",
"C.",
""
],
[
"Jahnke",
"F.",
""
],
[
"Reuter",
"D.",
""
],
[
"Wieck",
"A. D.",
""
]
] |
0706.3674 | Fran\c{c}ois Charles | Fran\c{c}ois Charles | Conjugate varieties with distinct real cohomology algebras | 18 pages, final version | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Using constructions of Voisin, we exhibit a smooth projective variety defined
over a number field k and two complex embeddings of k, such that the two
complex manifolds induced by these embeddings have non isomorphic cohomology
algebras with real coefficients. This contrasts with the fact that the
cohomology algebras with l-adic coefficients are canonically isomorphic for any
prime number l, and answers a question of Grothendieck.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 16:49:32 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 12:51:33 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jul 2008 04:05:54 GMT"
}
] | 2008-07-15T00:00:00 | [
[
"Charles",
"François",
""
]
] |
0706.3675 | Kuo-An Wu | Kuo-An Wu and Alain Karma | Phase-field crystal modeling of equilibrium bcc-liquid interfaces | 12 pages, 2 figures | null | 10.1103/PhysRevB.76.184107 | null | cond-mat.mtrl-sci | null | We investigate the equilibrium properties of bcc-liquid interfaces modeled
with a continuum phase-field crystal (PFC) approach [K. R. Elder and M. Grant,
Phys. Rev. E 70, 051605 (2004)]. A multiscale analysis of the PFC model is
carried out which exploits the fact that the amplitudes of crystal density
waves decay slowly into the liquid in the physically relevant limit where the
freezing transition is weakly first order. This analysis yields a set of
coupled equations for these amplitudes that is similar to the set of equations
derived from Ginzburg-Landau (GL) theory [K.-A. Wu et al., Phys. Rev. E 73,
094101 (2006)]. The two sets only differ in the details of higher order
nonlinear couplings between different density waves, which is determined by the
form of the nonlinearity assumed in the PFC model and by the ansatz that all
polygons with the same number of sides have equal weight in GL theory. Despite
these differences, for parameters (liquid structure factor and solid density
wave amplitude) of Fe determined from molecular dynamic (MD) simulations, the
PFC and GL amplitude equations yield very similar predictions for the overall
magnitude and anisotropy of the interfacial free-energy and density wave
profiles. These predictions are compared with MD simulations as well as
numerical solutions of the PFC model.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:05:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wu",
"Kuo-An",
""
],
[
"Karma",
"Alain",
""
]
] |
0706.3676 | Marcin Molski | Marcin Molski and Jerzy Konarski | On the Gompertzian dynamics of growth and self-organization | null | null | null | null | q-bio.OT q-bio.QM | null | Comment on the Waliszewski's article "A principle of fractal-sto-chastic
dualism and Gompertzian dynamics of growth and self-organization" (BioSystems
82 (2005)61-73) is presented. It has been proved that the main idea of this
work that Gompertzian dynamics is governed by the Schr\"{o}dinger-like equation
including anharmonic Morse potential has been already introduced by Molski and
Konarski in 2003. Some inconsistencies and mathematical errors in the
Waliszewski's model are also pointed out.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:11:09 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Molski",
"Marcin",
""
],
[
"Konarski",
"Jerzy",
""
]
] |
0706.3677 | Keith Copsey | Keith Copsey | Bubbles Unbound II: AdS and the Single Bubble | 42 pages, 11 figures, v2: minor improvements, v3: added references,
enhanced soliton discussion, typos corrected, published version | JHEP 0710:095,2007 | 10.1088/1126-6708/2007/10/095 | null | hep-th gr-qc | null | I present further analytic time symmetric initial data for five dimensions
describing ``bubbles of nothing'' which have no Kaluza-Klein circle
asymptotically. The new solutions consist of a large family of single bubbles
in both asymptotically flat and asymptotically AdS space. I also numerically
construct gravitational solitons in AdS where the usual boundary conditions are
modified geometrically but not topologically. Furthermore I point out there are
both regular AdS bubbles and topologically trivial metrics in asymptotically
global AdS dual to matter which violates all the usual energy conditions, both
classical and quantum. I inquire as to the existence of a dual gravitational
instability.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:46:23 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 18:26:59 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Dec 2007 19:34:42 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Copsey",
"Keith",
""
]
] |
0706.3678 | Ioan Kosztin | Cyrille Norotte, Francoise Marga, Adrian Neagu, Ioan Kosztin and Gabor
Forgacs (University of Missouri - Columbia) | Experimental confirmation of tissue liquidity based on the exact
solution of the Laplace equation | 4 pages, 3 figures, submitted to Phys. Rev. Lett | null | 10.1209/0295-5075/81/46003 | null | physics.bio-ph physics.flu-dyn q-bio.TO | null | The notion of tissue surface tension has provided a physical understanding of
morphogenetic phenomena such as tissue spreading or cell sorting. The
measurement of tissue surface tension so far relied on strong approximations on
the geometric profile of a spherical droplet compressed between parallel
plates. We solved the Laplace equation for this geometry and tested its
solution on true liquids and embryonic tissue fragments as well as
multicellular aggregates. The analytic solution provides the surface tension in
terms of easily and accurately measurable geometric parameters. Experimental
results show that the various tissues and multicellular aggregates studied here
are incompressible and, similarly to true liquids, possess effective surface
tensions that are independent of the magnitude of the compressive force and the
volume of the droplet.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:24:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Norotte",
"Cyrille",
"",
"University of Missouri - Columbia"
],
[
"Marga",
"Francoise",
"",
"University of Missouri - Columbia"
],
[
"Neagu",
"Adrian",
"",
"University of Missouri - Columbia"
],
[
"Kosztin",
"Ioan",
"",
"University of Missouri - Columbia"
],
[
"Forgacs",
"Gabor",
"",
"University of Missouri - Columbia"
]
] |
0706.3679 | Yann Guermeur | Yann Guermeur (LORIA) | Scale-sensitive Psi-dimensions: the Capacity Measures for Classifiers
Taking Values in R^Q | null | ASMDA 2007 (2007) 1-8 | null | null | cs.LG | null | Bounds on the risk play a crucial role in statistical learning theory. They
usually involve as capacity measure of the model studied the VC dimension or
one of its extensions. In classification, such "VC dimensions" exist for models
taking values in {0, 1}, {1,..., Q} and R. We introduce the generalizations
appropriate for the missing case, the one of models with values in R^Q. This
provides us with a new guaranteed risk for M-SVMs which appears superior to the
existing one.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:28:57 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Guermeur",
"Yann",
"",
"LORIA"
]
] |
0706.3680 | Gad Naot | Gad Naot | The Universal sl_2 Link Homology Theory | 97 pages. This is my PhD thesis (University of Toronto, June 2007).
Hooray! | null | null | null | math.GT math.QA | null | We explore the complex associated to a link in the geometric formalism of
Khovanov's (n=2) link homology theory, determine its exact underlying algebraic
structure and find its precise universality properties for link homology
functors. We present new methods of extracting all known link homology theories
directly from this universal complex, and determine its relative strength as a
link invariant by specifying the amount of information held within the complex.
We achieve these goals by finding a complex isomorphism which reduces the
complex into one in a simpler category. We introduce few tools and methods,
including surface classification modulo the 4TU/S/T relations and genus
generating operators, and use them to explore the relation between the
geometric complex and its underlying algebraic structure. We identify the
universal topological quantum field theory (TQFT) that can be used to create
link homology and find that it is ``smaller'' than what was previously reported
by Khovanov. We find new homology theories that hold a controlled amount of
information relative to the known ones.
The universal complex is computable efficiently using our reduction theorem.
This allows us to explore the phenomenological aspects of link homology theory
through the eyes of the universal complex in order to explain and unify various
phenomena (such as torsion and thickness). The universal theory also enables us
to state results regarding specific link homology theories derived from it. The
methods developed in this thesis can be combined with other known techniques
(such as link homology spectral sequences) or used in the various extensions of
Khovanov link homology (such as sl_3 link homology).
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 19:59:51 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Naot",
"Gad",
""
]
] |
0706.3681 | Marcin Molski | Marcin Molski | On the Classification Scheme for Phenomenological Universalities in
Growth Problems in Physics and Other Sciences | null | null | null | null | q-bio.OT q-bio.QM | null | Comment on "Classification Scheme for Phenomenological Universalities in
Growth Problems in Physics and Other Sciences" by P. Castorina, P. P. Delsanto
and C. Guiot, Phys. Rev. Lett. {\bf 96}, 188701 (2006) is presented. It has
been proved that the West-like function of growth derived by the authors is
incorrect and the approach does not take into account the growth of the
biological systems undergoing atrophy or demographic and economic systems
undergoing involution or regression. A simple extension of the model, which
permits derivation of the so far unknown involuted Gompertz function of growth
is proposed.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:40:10 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Molski",
"Marcin",
""
]
] |
0706.3682 | Richard J. Mathar | Richard J. Mathar | Orthogonal Set of Basis Functions over the Binocular Pupil | Added chapters V and VI on interferometric signal and Fourier
representation | Baltic Astronomy 19 (2010) 121-141 | 10.1515/astro-2017-0416 | null | physics.optics | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Sets of orthogonal basis functions over two-dimensional circular areas--most
often representing pupils in optical applications--are known in the literature
for the full circle (Zernike or Jacobi polynomials) and the annulus. This work
proposes an orthogonal set if the area is two non-overlapping circular pupils
of same size. The major free parameter is the ratio of the pupil radii over the
distance between both circles. Increasingly higher order aberrations--as
defined for a virtual larger pupil in which both pupils are embedded--are fed
into a Gram-Schmidt orthogonalization to implement one unique set of basis
functions. The key element is to work out the overlap integrals between a full
set of primitive basis functions (products of powers of the distance from the
mid-point between both pupils by azimuthal functions of the Fourier type).
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:20:55 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Aug 2008 20:05:16 GMT"
}
] | 2017-05-08T00:00:00 | [
[
"Mathar",
"Richard J.",
""
]
] |
0706.3683 | Andrej Prsa | Andrej Prsa and Tomaz Zwitter | Pipeline Reduction of Binary Light Curves from Large-Scale Surveys | 14 pages, 8 figures, S240 IAU symposium proceedings | null | 10.1017/S1743921307004061 | null | astro-ph | null | One of the most important changes in observational astronomy of the 21st
Century is a rapid shift from classical object-by-object observations to
extensive automatic surveys. As CCD detectors are getting better and their
prices are getting lower, more and more small and medium-size observatories are
refocusing their attention to detection of stellar variability through
systematic sky-scanning missions. This trend is aditionally powered by the
success of pioneering surveys such as ASAS, DENIS, OGLE, TASS, their space
counterpart Hipparcos and others. Such surveys produce massive amounts of data
and it is not at all clear how these data are to be reduced and analysed. This
is especially striking in the eclipsing binary (EB) field, where most
frequently used tools are optimized for object-by-object analysis. A clear need
for thorough, reliable and fully automated approaches to modeling and analysis
of EB data is thus obvious. This task is very difficult because of limited data
quality, non-uniform phase coverage and solution degeneracy. This paper reviews
recent advancements in putting together semi-automatic and fully automatic
pipelines for EB data processing. Automatic procedures have already been used
to process Hipparcos data, LMC/SMC observations, OGLE and ASAS catalogs etc. We
discuss the advantages and shortcomings of these procedures.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:49:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Prsa",
"Andrej",
""
],
[
"Zwitter",
"Tomaz",
""
]
] |
0706.3684 | Pete Donnell | Pete Donnell, Murad Banaji and Stephen Baigent | Stability in generic mitochondrial models | 22 pages, 1 figure. Submitted to Mathematical Biosciences | null | null | null | q-bio.QM q-bio.SC | null | In this paper, we use a variety of mathematical techniques to explore
existence, local stability, and global stability of equilibria in abstract
models of mitochondrial metabolism. The class of models constructed is defined
by the biological description of the system, with minimal mathematical
assumptions. The key features are an electron transport chain coupled to a
process of charge translocation across a membrane. In the absence of charge
translocation these models have previously been shown to behave in a very
simple manner with a single, globally stable equilibrium. We show that with
charge translocation the conclusion about a unique equilibrium remains true,
but local and global stability do not necessarily follow. In sufficiently low
dimensions - i.e. for short electron transport chains - it is possible to make
claims about local and global stability of the equilibrium. On the other hand,
for longer chains, these general claims are no longer valid. Some particular
conditions which ensure stability of the equilibrium for chains of arbitrary
length are presented.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 17:55:06 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Donnell",
"Pete",
""
],
[
"Banaji",
"Murad",
""
],
[
"Baigent",
"Stephen",
""
]
] |
0706.3685 | Yu Jia | Yu Jia | Exclusive Double Charmonium Production from $\Upsilon$ Decay | null | Phys.Rev.D76:074007,2007 | 10.1103/PhysRevD.76.074007 | null | hep-ph hep-ex | null | The exclusive decay of $\Upsilon$ to a vector plus pseudoscalar charmonium is
studied in perturbative QCD. The corresponding branching ratios are predicted
to be of order $10^{-6}$ for first three $\Upsilon$ resonances, and we expect
these decay modes should be discovered in the prospective high-luminosity
$e^+e^-$ facilities such as super $B$ experiment. As a manifestation of the
short-distance loop contribution, the relative phases among strong,
electromagnetic and radiative decay amplitudes can be deduced. It is
particularly interesting to find that the relative phase between strong and
electromagnetic amplitudes is nearly orthogonal. The resonance-continuum
interference effect for double charmonium production near various $\Upsilon$
resonances in $e^+e^-$ annihilation is addressed.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:27:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Jia",
"Yu",
""
]
] |
0706.3686 | Jonathan Keeling | Jonathan Keeling, Natalia G. Berloff | Spontaneous rotating vortex lattices in a pumped decaying condensate | Updated title and introduction. 4 pages, 3 figures | Phys. Rev. Lett. 100, 250401 (2008) | 10.1103/PhysRevLett.100.250401 | null | cond-mat.other | null | Injection and decay of particles in an inhomogeneous quantum condensate can
significantly change its behaviour. We model trapped, pumped, decaying
condensates by a complex Gross-Pitaevskii equation and analyse the density and
currents in the steady state. With homogeneous pumping, rotationally symmetric
solutions are unstable. Stability may be restored by a finite pumping spot.
However if the pumping spot is larger than the Thomas-Fermi cloud radius, then
rotationally symmetric solutions are replaced by solutions with spontaneous
arrays of vortices. These vortex arrays arise without any rotation of the trap,
spontaneously breaking rotational symmetry.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:01:59 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Feb 2008 09:58:02 GMT"
},
{
"version": "v3",
"created": "Mon, 2 Jun 2008 08:37:42 GMT"
}
] | 2008-06-23T00:00:00 | [
[
"Keeling",
"Jonathan",
""
],
[
"Berloff",
"Natalia G.",
""
]
] |
0706.3687 | Claire Postlethwaite | Claire M. Postlethwaite and Mary Silber | Stabilizing unstable periodic orbits in the Lorenz equations using
time-delayed feedback control | 21 pages, 8 figures, to appear in PRE | null | 10.1103/PhysRevE.76.056214 | null | nlin.CD | null | For many years it was believed that an unstable periodic orbit with an odd
number of real Floquet multipliers greater than unity cannot be stabilized by
the time-delayed feedback control mechanism of Pyragus. A recent paper by
Fiedler et al uses the normal form of a subcritical Hopf bifurcation to give a
counterexample to this theorem. Using the Lorenz equations as an example, we
demonstrate that the stabilization mechanism identified by Fiedler et al for
the Hopf normal form can also apply to unstable periodic orbits created by
subcritical Hopf bifurcations in higher-dimensional dynamical systems. Our
analysis focuses on a particular codimension-two bifurcation that captures the
stabilization mechanism in the Hopf normal form example, and we show that the
same codimension-two bifurcation is present in the Lorenz equations with
appropriately chosen Pyragus-type time-delayed feedback. This example suggests
a possible strategy for choosing the feedback gain matrix in Pyragus control of
unstable periodic orbits that arise from a subcritical Hopf bifurcation of a
stable equilibrium. In particular, our choice of feedback gain matrix is
informed by the Fiedler et al example, and it works over a broad range of
parameters, despite the fact that a center-manifold reduction of the
higher-dimensional problem does not lead to their model problem.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:12:51 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Oct 2007 15:03:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Postlethwaite",
"Claire M.",
""
],
[
"Silber",
"Mary",
""
]
] |
0706.3688 | Ali Chamseddine | Ali H. Chamseddine and Alain Connes | Why the Standard Model | 13 pages | J.Geom.Phys.58:38-47,2008 | 10.1016/j.geomphys.2007.09.011 | null | hep-th math.OA | null | The Standard Model is based on the gauge invariance principle with gauge
group U(1)xSU(2)xSU(3) and suitable representations for fermions and bosons,
which are begging for a conceptual understanding. We propose a purely
gravitational explanation: space-time has a fine structure given as a product
of a four dimensional continuum by a finite noncommutative geometry F. The
raison d'etre for F is to correct the K-theoretic dimension from four to ten
(modulo eight). We classify the irreducible finite noncommutative geometries of
K-theoretic dimension six and show that the dimension (per generation) is a
square of an integer k. Under an additional hypothesis of quaternion linearity,
the geometry which reproduces the Standard Model is singled out (and one gets
k=4)with the correct quantum numbers for all fields. The spectral action
applied to the product MxF delivers the full Standard Model,with neutrino
mixing, coupled to gravity, and makes predictions(the number of generations is
still an input).
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:06:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chamseddine",
"Ali H.",
""
],
[
"Connes",
"Alain",
""
]
] |
0706.3689 | Albert Fannjiang | Albert C. Fannjiang | Space-frequency correlation of classical waves in disordered media:
high-frequency and small scale asymptotics | null | null | 10.1209/0295-5075/80/14005 | null | physics.optics physics.gen-ph | null | Two-frequency radiative transfer (2f-RT) theory is developed for geometrical
optics in random media. The space-frequency correlation is described by the
two-frequency Wigner distribution (2f-WD) which satisfies a closed form
equation, the two-frequency Wigner-Moyal equation. In the RT regime it is
proved rigorously that 2f-WD satisfies a Fokker-Planck-like equation with
complex-valued coefficients. By dimensional analysis 2f-RT equation yields the
scaling behavior of three physical parameters: the spatial spread, the
coherence length and the coherence bandwidth. The sub-transport-mean-free-path
behavior is obtained in a closed form by analytically solving a paraxial 2f-RT
equation.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:08:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fannjiang",
"Albert C.",
""
]
] |
0706.3690 | Ali Chamseddine | Ali H. Chamseddine, Alain Connes | Conceptual Explanation for the Algebra in the Noncommutative Approach to
the Standard Model | Title change only. The title "A Dress for SM the Beggar" was changed
by the Editor of Physical Review Letters | Phys.Rev.Lett.99:191601,2007 | 10.1103/PhysRevLett.99.191601 | null | hep-th hep-ph | null | The purpose of this letter is to remove the arbitrariness of the ad hoc
choice of the algebra and its representation in the noncommutative approach to
the Standard Model, which was begging for a conceptual explanation. We assume
as before that space-time is the product of a four-dimensional manifold by a
finite noncommmutative space F. The spectral action is the pure gravitational
action for the product space. To remove the above arbitrariness, we classify
the irreducibe geometries F consistent with imposing reality and chiral
conditions on spinors, to avoid the fermion doubling problem, which amounts to
have total dimension 10 (in the K-theoretic sense). It gives, almost uniquely,
the Standard Model with all its details, predicting the number of fermions per
generation to be 16, their representations and the Higgs breaking mechanism,
with very little input. The geometrical model is valid at the unification
scale, and has relations connecting the gauge couplings to each other and to
the Higgs coupling. This gives a prediction of the Higgs mass of around 170 GeV
and a mass relation connecting the sum of the square of the masses of the
fermions to the W mass square, which enables us to predict the top quark mass
compatible with the measured experimental value. We thus manage to have the
advantages of both SO(10) and Kaluza-Klein unification, without paying the
price of plethora of Higgs fields or the infinite tower of states.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:18:23 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 15:46:24 GMT"
},
{
"version": "v3",
"created": "Wed, 21 Nov 2007 08:09:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chamseddine",
"Ali H.",
""
],
[
"Connes",
"Alain",
""
]
] |
0706.3691 | Loic Vanel | Pierre-Philippe Cortet (Phys-ENS), St\'ephane Santucci (Phys-ENS),
Loic Vanel (Phys-ENS), Sergio Ciliberto (Phys-ENS) | Slow crack growth in polycarbonate films | null | Europhysics Letters (EPL) 2, 71 (15/07/2005) 242 | 10.1209/epl/i2005-10077-3 | null | cond-mat.mtrl-sci physics.class-ph | null | We study experimentally the slow growth of a single crack in polycarbonate
films submitted to uniaxial and constant imposed stress. The specificity of
fracture in polycarbonate films is the appearance of flame shaped macroscopic
process zones at the tips of the crack. Supported by an experimental study of
the mechanical properties of polycarbonate films, an analysis of the stress
dependence of the mean ratio between the process zone and crack lengths, during
the crack growth, show a quantitative agreement with the Dugdale-Barenblatt
model of the plastic process zone. We find that the fracture growth curves obey
strong scaling properties that lead to a well defined growth master curve.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:23:58 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Cortet",
"Pierre-Philippe",
"",
"Phys-ENS"
],
[
"Santucci",
"Stéphane",
"",
"Phys-ENS"
],
[
"Vanel",
"Loic",
"",
"Phys-ENS"
],
[
"Ciliberto",
"Sergio",
"",
"Phys-ENS"
]
] |
0706.3692 | Guy D. Moore | Guy D. Moore | Next-to-Leading Order Shear Viscosity in lambda phi^4 Theory | 4 pages, 1 figure. Typos fixed, tiny change in discussion | Phys.Rev.D76:107702,2007 | 10.1103/PhysRevD.76.107702 | null | hep-ph | null | We show that the shear viscosity of lambda phi^4 theory is sensitive at
next-to-leading order to soft physics, which gives rise to subleading
corrections suppressed by only a half power of the coupling, eta = [3033.54 +
1548.3 m_{th}/T] N T^3]/[ (N+2)/3 lambda^2], with m^2_th=(N+2)/72 lambda T^2.
The series appears to converge about as well (or badly) as the series for the
pressure.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:40:22 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Sep 2007 15:05:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Moore",
"Guy D.",
""
]
] |
0706.3693 | Ioan Kosztin | Elijah Flenner, Francoise Marga, Adrian Neagu, Ioan Kosztin and Gabor
Forgacs (University of Missouri - Columbia) | Relating Biophysical Properties Across Scales | 24 pages, 10 figures, To appear in Current Topics in Developmental
Biology | null | null | null | physics.bio-ph physics.comp-ph q-bio.CB q-bio.TO | null | A distinguishing feature of a multicellular living system is that it operates
at various scales, from the intracellular to organismal. Very little is known
at present on how tissue level properties are related to cell and subcellular
properties. Modern measurement techniques provide quantitative results at both
the intracellular and tissue level, but not on the connection between these. In
the present work we outline a framework to address this connection. We
specifically concentrate on the morphogenetic process of tissue fusion, by
following the coalescence of two contiguous multicellular aggregates. The time
evolution of this process can accurately be described by the theory of viscous
liquids. We also study fusion by Monte Carlo simulations and a novel Cellular
Particle Dynamics (CPD) model, which is similar to the earlier introduced
Subcellular Element Model (Newman, 2005). Using the combination of experiments,
theory and modeling we are able to relate the measured tissue level biophysical
quantities to subcellular parameters. Our approach has validity beyond the
particular morphogenetic process considered here and provides a general way to
relate biophysical properties across scales.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:50:13 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Flenner",
"Elijah",
"",
"University of Missouri - Columbia"
],
[
"Marga",
"Francoise",
"",
"University of Missouri - Columbia"
],
[
"Neagu",
"Adrian",
"",
"University of Missouri - Columbia"
],
[
"Kosztin",
"Ioan",
"",
"University of Missouri - Columbia"
],
[
"Forgacs",
"Gabor",
"",
"University of Missouri - Columbia"
]
] |
0706.3694 | Laurent Favart | L. Favart | Status of the H1 Very Forward Proton Spectrometer | Proceedings of DIS07, 4 pages | null | null | null | physics.ins-det | null | The Very Forward Proton Spectrometer (VFPS) of the H1 experiment at HERA is
collecting data since 2005. The fiber detectors in the Roman pots located at
218 and 222m downstream from the H1 interaction point, tag and measure
diffractively scattered protons with a high acceptance in the $\xpom$ range
[0.01, 0.025]. The experimental set up and the spectrometer tagging performance
using diffractive events collected during 2006 and 2007 are discussed.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 18:43:33 GMT"
}
] | 2007-06-26T00:00:00 | [
[
"Favart",
"L.",
""
]
] |
0706.3695 | Danil Boukhvalov W | D. W. Boukhvalov, Yu. N. Gornostyrev, M. I. Katsnelson, A. I.
Lichtenstein | Magnetism and local distortions near carbon impurity in $\gamma$-iron | 4 pages 3 figures. Final version, accepted to Phys.Rev. Lett | Phys. Rev. Lett. 99, 247205 (2007) | 10.1103/PhysRevLett.99.247205 | null | cond-mat.mtrl-sci | null | Local perturbations of crystal and magnetic structure of $\gamma$-iron near
carbon interstitial impurity is investigated by {\it ab initio} electronic
structure calculations. It is shown that the carbon impurity creates locally a
region of ferromagnetic ordering with substantial tetragonal distortions.
Exchange integrals and solution enthalpy are calculated, the latter being in a
very good agreement with experimental data. Effect of the local distortions on
the carbon-carbon interactions in $\gamma$-iron is discussed.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 19:05:04 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 09:58:05 GMT"
}
] | 2008-09-05T00:00:00 | [
[
"Boukhvalov",
"D. W.",
""
],
[
"Gornostyrev",
"Yu. N.",
""
],
[
"Katsnelson",
"M. I.",
""
],
[
"Lichtenstein",
"A. I.",
""
]
] |
0706.3696 | Victor Guillemin | Victor Guillemin and Zuoqin Wang | The Mellin transform and spectral properties of toric varieties | null | null | null | null | math.SG | null | In this article we apply results of \cite{W} on the twisted Mellin transform
to problems in toric geometry. In particular we use these results to describe
the asymptotics of probability densities associated with the monomial
eigenstates, $z^k$, $k \in \ZZ^d$, in Bargmann space and prove an "upstairs"
version of the spectral density theorem of \cite{BGU}. We also obtain for the
$z^k$'s, "upstairs" versions of the results of \cite{STZ} on distribution laws
for eigenstates on toric varieties.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 19:10:41 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 16:10:40 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Guillemin",
"Victor",
""
],
[
"Wang",
"Zuoqin",
""
]
] |
0706.3697 | Amelia Sparavigna | J. Avloni, L. Florio, A.R. Henn and A. Sparavigna | Thermal electric effects and heat generation in polypyrrole coated PET
fabrics | 12 pages and 9 figures | Materials Sciences and Applications, Vol. 1 No. 4, 2010, pp.
253-259 | 10.4236/msa.2010.14037 | null | cond-mat.mtrl-sci | null | Polypyrrole chemically synthesized on PET gives rise to textiles with a high
electric conductivity, suitable for several applications from antistatics to
electromagnetic interference shielding devices. Here, we discuss investigations
on thermal electric performances of the polypyrrole coated PET in a wide range
of temperatures above room temperature. The Seebeck coefficient turns out to be
comparable with that of metal thermocouple materials. Since polypyrrole shows
extremely low thermal diffusivities regardless of the electrical conductivity,
the low thermal conductivity gives significant advantage to the thermoelectric
figure-of-merit ZT, comparable with that of some traditional inorganic
thermoelectric materials. The heat generation is also investigated for possible
heating textile devices.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 19:18:21 GMT"
}
] | 2014-01-15T00:00:00 | [
[
"Avloni",
"J.",
""
],
[
"Florio",
"L.",
""
],
[
"Henn",
"A. R.",
""
],
[
"Sparavigna",
"A.",
""
]
] |
0706.3698 | Andrey N. Timokhin | A.N. Timokhin (1,2), D. Eichler (1), Yu. Lyubarsky (1) ((1) Ben-Gurion
University of the Negev, Beer-Sheva, Israel; (2) Sternberg Astronomical
Institute, Moscow, Russia) | On the nature of QPO in the tail of SGR giant flares | 7 pages, 4 figures, emulateapj style | Astrophys.J.680:1398-1404,2008 | 10.1086/587925 | null | astro-ph | null | A model is presented for the quasiperiodic component of magnetar emission
during the tail phase of giant flares. The model invokes modulation of the
particle number density in the magnetosphere. The magnetospheric currents are
modulated by torsional motion of the surface and we calculate that the
amplitude of neutron star surface oscillation should be ~1% of the NS radius in
order to produce the observed features in the power spectrum. Using an
axisymmetric analytical model for structure of the magnetosphere of an
oscillating NS, we calculate the angular distribution of the optical depth to
the resonant Compton scattering. The anisotropy of the optical depth may be why
QPO are observed only at particular rotational phases.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:23:49 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Timokhin",
"A. N.",
""
],
[
"Eichler",
"D.",
""
],
[
"Lyubarsky",
"Yu.",
""
]
] |
0706.3699 | William H. Kinney | William H. Kinney (Univ. at Buffalo, SUNY) | Inflation after WMAP3 | To appear in the proceedings of Colliders to Cosmic Rays 2007. 8
pages, 2 figures. (V2: Minor typo corrected) | AIP Conf.Proc.928:3-10,2007 | 10.1063/1.2775890 | null | astro-ph hep-ph | null | I discuss the current status of inflationary cosmology in light of the recent
WMAP 3-year data release. The basic predictions of inflation are all supported
by the data. Inflation also makes predictions which have not been well tested
by current data but can be by future experiments, most notably a deviation from
a scale-invariant power spectrum and the production of primordial gravitational
waves. A scale-invariant spectrum is disfavored by current data, but not
conclusively. Tensor modes are currently poorly constrained, and slow-roll
inflation does not make an unambiguous prediction of the expected amplitude of
primordial gravitational waves. A tensor/scalar ratio of $r \simeq 0.01$ is
within reach of near-future measurements.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:33:46 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 20:23:54 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kinney",
"William H.",
"",
"Univ. at Buffalo, SUNY"
]
] |
0706.3700 | Bart Willems | B. Willems (1), A. Vecchio (1,2), V. Kalogera (1) ((1) Northwestern
U., (2) U. of Birmingham) | Probing white dwarf interiors with LISA: periastron precession in double
white dwarfs | PRL, in press (expected publication date January 22, 2008) | Phys.Rev.Lett.100:041102,2008; Erratum-ibid.101:219903,2008 | 10.1103/PhysRevLett.100.041102 | null | astro-ph gr-qc | null | In globular clusters, dynamical interactions give rise to a population of
eccentric double white dwarfs detectable by the Laser Interferometer Space
Antenna (LISA) up to the Large Magellanic Cloud. In this Letter, we explore the
detectability of periastron precession in these systems with LISA. Unlike
previous investigations, we consider contributions due to tidal and rotational
distortions of the binary components in addition to general relativistic
contributions to the periastron precession. At orbital frequencies above a few
mHz, we find that tides and stellar rotation dominate, opening up a possibly
unique window to the study of the interior and structure of white dwarfs.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:00:33 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Jan 2008 18:53:22 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Willems",
"B.",
""
],
[
"Vecchio",
"A.",
""
],
[
"Kalogera",
"V.",
""
]
] |
0706.3701 | Fabrizio Illuminati | F. Dell'Anno, S. De Siena, L. Albano Farias, F. Illuminati | Continuous variable quantum teleportation with non-Gaussian resources | 12 pages, 12 figures | Phys. Rev. A 76, 022301 (2007) | 10.1103/PhysRevA.76.022301 | null | quant-ph | null | We investigate continuous variable quantum teleportation using non-Gaussian
states of the radiation field as entangled resources. We compare the
performance of different classes of degaussified resources, including two-mode
photon-added and two-mode photon-subtracted squeezed states. We then introduce
a class of two-mode squeezed Bell-like states with one-parameter dependence for
optimization. These states interpolate between and include as subcases
different classes of degaussified resources. We show that optimized squeezed
Bell-like resources yield a remarkable improvement in the fidelity of
teleportation both for coherent and nonclassical input states. The
investigation reveals that the optimal non-Gaussian resources for continuous
variable teleportation are those that most closely realize the simultaneous
maximization of the content of entanglement, the degree of affinity with the
two-mode squeezed vacuum and the, suitably measured, amount of non-Gaussianity.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:09:32 GMT"
}
] | 2007-08-03T00:00:00 | [
[
"Dell'Anno",
"F.",
""
],
[
"De Siena",
"S.",
""
],
[
"Farias",
"L. Albano",
""
],
[
"Illuminati",
"F.",
""
]
] |
0706.3702 | Mark R. Krumholz | Mark R. Krumholz (Princeton University) | From Massive Cores to Massive Stars | 8 pages, 2 figures, ASP format, to be published in "Pathways Through
an Eclectic Universe", eds. J. Knapen, T. Mahoney, & A. Vazdekis | null | null | null | astro-ph | null | The similarity between the mass and spatial distributions of pre-stellar gas
cores in star-forming clouds and young stars in clusters provides strong
circumstantial evidence that these gas cores are the direct progenitors of
individual stars. Here I describe a physical model for the evolution of massive
cores into stars, starting with the initial phases of collapse and
fragmentation, through disk formation and fragmentation, the later phases of
stellar feedback, and finally interaction of the newly formed stars with their
environments. This model shows that a direct mapping from cores to stars is the
natural physical outcome of massive core evolution, and thereby allows us to
explain many of the properties of young star clusters as direct imprints of
their gas-phase progenitors.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:10:32 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Krumholz",
"Mark R.",
"",
"Princeton University"
]
] |
0706.3703 | Xufen Wu | Xufen Wu, HongSheng Zhao, Benoit Famaey, G. Gentile, O. Tiret, F.
Combes, G.W. Angus, A.C. Robin | Loss of mass and stability of galaxies in MOND | 4 pages, 2 figures, ApJ Letters | Astrophys.J. 665 (2007) L101-L104 | 10.1086/521103 | null | astro-ph | null | The self-binding energy and stability of a galaxy in MOND-based gravity are
curiously decreasing functions of its center of mass acceleration towards
neighbouring mass concentrations. A tentative indication of this breaking of
the Strong Equivalence Principle in field galaxies is the RAVE-observed escape
speed in the Milky Way. Another consequence is that satellites of field
galaxies will move on nearly Keplerian orbits at large radii (100 - 500 kpc),
with a declining speed below the asymptotically constant naive MOND prediction.
But consequences of an environment-sensitive gravity are even more severe in
clusters, where member galaxies accelerate fast: no more Dark-Halo-like
potential is present to support galaxies, meaning that extended axisymmetric
disks of gas and stars are likely unstable. These predicted reappearance of
asymptotic Keplerian velocity curves and disappearance of "stereotypic
galaxies" in clusters are falsifiable with targeted surveys.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 18:24:02 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 16:06:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wu",
"Xufen",
""
],
[
"Zhao",
"HongSheng",
""
],
[
"Famaey",
"Benoit",
""
],
[
"Gentile",
"G.",
""
],
[
"Tiret",
"O.",
""
],
[
"Combes",
"F.",
""
],
[
"Angus",
"G. W.",
""
],
[
"Robin",
"A. C.",
""
]
] |
0706.3704 | Stephen Kane | Stephen R. Kane | Detectability of Exoplanetary Transits from Radial Velocity Surveys | 11 pages, 8 figures, accepted for publication in MNRAS, minor
correction | Mon.Not.Roy.Astron.Soc.380:1488-1496,2007 | 10.1111/j.1365-2966.2007.12144.x | null | astro-ph | null | Of the known transiting extra-solar planets, a few have been detected through
photometric follow-up observations of radial velocity planets. Perhaps the best
known of these is the transiting exoplanet HD 209458b. For hot Jupiters
(periods less than ~5 days), the a priori information that 10% of these planets
will transit their parent star due to the geometric transit probability leads
to an estimate of the expected transit yields from radial velocity surveys. The
radial velocity information can be used to construct an effective photometric
follow-up strategy which will provide optimal detection of possible transits.
Since the planet-harbouring stars are already known in this case, one is only
limited by the photometric precision achieveable by the chosen
telescope/instrument. The radial velocity modelling code presented here
automatically produces a transit ephemeris for each planet dataset fitted by
the program. Since the transit duration is brief compared with the fitted
period, we calculate the maximum window for obtaining photometric transit
observations after the radial velocity data have been obtained, generalising
for eccentric orbits. We discuss a typically employed survey strategy which may
contribute to a possible radial velocity bias against detection of the very hot
Jupiters which have dominated the transit discoveries. Finally, we describe how
these methods can be applied to current and future radial velocity surveys.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:15:09 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jul 2007 11:47:08 GMT"
},
{
"version": "v3",
"created": "Sun, 16 Sep 2007 18:42:00 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kane",
"Stephen R.",
""
]
] |
0706.3705 | Antoine Letessier-Selvon | Pierre Billoir and Antoine Letessier-Selvon | A coverage independent method to analyze large scale anisotropies | 8 pages, 6 figures | Astropart.Phys.29:14-19,2008 | 10.1016/j.astropartphys.2007.11.004 | null | astro-ph | null | The arrival time distribution of cosmic ray events is well suited to extract
information regarding sky anisotropies. For an experiment with nearly constant
exposure, the frequency resolution one can achieve is given by the inverse of
the time $T$ during which the data was recorded. For $T$ larger than one
calendar year the resolution becomes sufficient to resolve the sidereal and
diurnal frequencies. Using a Fourier expansion on a modified time parameter, we
show in this note that one can accurately extract sidereal modulations without
knowledge of the experimental coverage. This procedure also gives the full
frequency pattern of the event sample under studies which contains important
information about possible systematics entering in the sidereal analysis. We
also show how this method allows to correct for those systematics. Finally, we
show that a two dimensional analysis, in the form of the spherical harmonic
($Y_l^m$) decomposition, can be performed under the same conditions for all
$m\ne 0$.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:15:52 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Billoir",
"Pierre",
""
],
[
"Letessier-Selvon",
"Antoine",
""
]
] |
0706.3706 | Yuexing Li | Yuexing Li, Philip F. Hopkins, Lars Hernquist, Douglas P. Finkbeiner,
Thomas J. Cox (Harvard/CfA), Volker Springel (MPA), Linhua Jiang, Xiaohui Fan
(Arizona), Naoki Yoshida (Nagoya) | Modeling the Dust Properties of z ~ 6 Quasars with ART^2 --
All-wavelength Radiative Transfer with Adaptive Refinement Tree | 26 pages, 22 figures, accepted by ApJ. Version with full resolution
images is available at
http://www.cfa.harvard.edu/~yxli/ARTDUST/astroph0706.3706.pdf | null | 10.1086/529364 | null | astro-ph | null | The detection of large quantities of dust in z ~ 6 quasars by infrared and
radio surveys presents puzzles for the formation and evolution of dust in these
early systems. Previously (Li et al. 2007), we showed that luminous quasars at
z > 6 can form through hierarchical mergers of gas-rich galaxies. Here, we
calculate the dust properties of simulated quasars and their progenitors using
a three-dimensional Monte Carlo radiative transfer code, ART^2 --
All-wavelength Radiative Transfer with Adaptive Refinement Tree. ART^2
incorporates a radiative equilibrium algorithm for dust emission, an adaptive
grid for inhomogeneous density, a multiphase model for the ISM, and a
supernova-origin dust model. We reproduce the SED and dust properties of SDSS
J1148+5251, and find that the infrared emission are closely associated with the
formation and evolution of the quasar host. The system evolves from a cold to a
warm ULIRG owing to heating and feedback from stars and AGN. Furthermore, the
AGN has significant implications for the interpretation of observation of the
hosts. Our results suggest that vigorous star formation in merging progenitors
is necessary to reproduce the observed dust properties of z~6 quasars,
supporting a merger-driven origin for luminous quasars at high redshifts and
the starburst-to-quasar evolutionary hypothesis. (Abridged)
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 03:57:05 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 21:40:18 GMT"
},
{
"version": "v3",
"created": "Wed, 9 Jan 2008 03:14:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Li",
"Yuexing",
"",
"Harvard/CfA"
],
[
"Hopkins",
"Philip F.",
"",
"Harvard/CfA"
],
[
"Hernquist",
"Lars",
"",
"Harvard/CfA"
],
[
"Finkbeiner",
"Douglas P.",
"",
"Harvard/CfA"
],
[
"Cox",
"Thomas J.",
"",
"Harvard/CfA"
],
[
"Springel",
"Volker",
"",
"MPA"
],
[
"Jiang",
"Linhua",
"",
"Arizona"
],
[
"Fan",
"Xiaohui",
"",
"Arizona"
],
[
"Yoshida",
"Naoki",
"",
"Nagoya"
]
] |
0706.3707 | Brian Harbourne | Cristiano Bocci (University of Siena), Brian Harbourne (University of
Nebraska) | Comparing powers and symbolic powers of ideals | 15 pages, to appear, Journal of Algebraic Geometry; version 2: minor
expositional changes, typos fixed, and references and Bocci's address updated | null | null | null | math.AG math.AC | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We develop tools to study the problem of containment of symbolic powers
$I^{(m)}$ in powers $I^r$ for a homogeneous ideal $I$ in a polynomial ring
$k[{\bf P}^N]$ in $N+1$ variables over an algebraically closed field $k$. We
obtain results on the structure of the set of pairs $(r,m)$ such that
$I^{(m)}\subseteq I^r$. As corollaries, we show that $I^2$ contains $I^{(3)}$
whenever $S$ is a finite generic set of points in ${\bf P}^2$ (thereby giving a
partial answer to a question of Huneke), and we show that the containment
theorems of Ein-Lazarsfeld-Smith and Hochster-Huneke are optimal for every
fixed dimension and codimension.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:31:35 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Jun 2009 14:20:24 GMT"
}
] | 2009-06-24T00:00:00 | [
[
"Bocci",
"Cristiano",
"",
"University of Siena"
],
[
"Harbourne",
"Brian",
"",
"University of\n Nebraska"
]
] |
0706.3708 | Steven G. Krantz | Steven G. Krantz and Marco M. Peloso | The Bergman kernel and projection on non-smooth worm domains | null | null | null | AIM 2007-29 | math.CV math.AP | null | This paper provides a precise asymptotic expansion for the Bergman kernel on
the non-smooth worm domains of Christer Kiselman in complex 2-space.
Applications are given to the failure of Condition R, to deviant boundary
behavior of the kernel, and to L^p mapping properties of the kernel.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:32:52 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Krantz",
"Steven G.",
""
],
[
"Peloso",
"Marco M.",
""
]
] |
0706.3709 | Ji\v{r}\'i Kub\'at | J. Kubat, D. Korcakova, A. Kawka, A. Pigulski, M. Slechta, P. Skoda | The H-alpha stellar and interstellar emission in the open cluster NGC
6910 | accepted to Astronomy and Astrophysics | Astronomy and Astrophysics 472 (2007), 163 - 167 | 10.1051/0004-6361:20077171 | null | astro-ph | null | We verify the nature of emission-line stars in the field of the open cluster
NGC 6910. % Spectroscopy in the H-alpha region was obtained. Raw CCD frames of
spectra of all stars fainter than V = 9 mag observed by us are significantly
affected by nebular emission originating in the surrounding HII region IC 1318.
After careful data reduction and subtraction of the nebular radiation we
succeeded in obtaining reliable stellar spectra. We confirm that the star NGC
6910 37 is a Be star, and we have corrected the classification of V1973 Cyg
from an Ae star to a normal A type star. Since the diffuse interstellar bands
do not appear in the spectrum of this star while being present in the other
stars we observed, we confirm that V1973 Cyg is a foreground object with
respect to IC 1318 and NGC 6910. We also find that the H-alpha line in HD
194279 has a P Cygni profile and the H-alpha line profile is variable in HD
229196.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:36:53 GMT"
}
] | 2007-08-16T00:00:00 | [
[
"Kubat",
"J.",
""
],
[
"Korcakova",
"D.",
""
],
[
"Kawka",
"A.",
""
],
[
"Pigulski",
"A.",
""
],
[
"Slechta",
"M.",
""
],
[
"Skoda",
"P.",
""
]
] |
0706.3710 | Shivratna Srinivasan | Shivratna Giri Srinivasan and Mahesh K. Varanasi | Optimal Constellations for the Low SNR Noncoherent MIMO Block Rayleigh
Fading Channel | 52 pages, to appear in IEEE Transactions on Information Theory | null | null | null | cs.IT math.IT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Reliable communication over the discrete-input/continuous-output noncoherent
multiple-input multiple-output (MIMO) Rayleigh block fading channel is
considered when the signal-to-noise ratio (SNR) per degree of freedom is low.
Two key problems are posed and solved to obtain the optimum discrete input. In
both problems, the average and peak power per space-time slot of the input
constellation are constrained. In the first one, the peak power to average
power ratio (PPAPR) of the input constellation is held fixed, while in the
second problem, the peak power is fixed independently of the average power. In
the first PPAPR-constrained problem, the mutual information, which grows as
O(SNR^2), is maximized up to second order in SNR. In the second
peak-constrained problem, where the mutual information behaves as O(SNR), the
structure of constellations that are optimal up to first order, or
equivalently, that minimize energy/bit, are explicitly characterized.
Furthermore, among constellations that are first-order optimal, those that
maximize the mutual information up to second order, or equivalently, the
wideband slope, are characterized. In both PPAPR-constrained and
peak-constrained problems, the optimal constellations are obtained in
closed-form as solutions to non-convex optimizations, and interestingly, they
are found to be identical. Due to its special structure, the common solution is
referred to as Space Time Orthogonal Rank one Modulation, or STORM. In both
problems, it is seen that STORM provides a sharp characterization of the
behavior of noncoherent MIMO capacity.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 20:40:45 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 00:40:49 GMT"
},
{
"version": "v3",
"created": "Mon, 22 Sep 2008 13:08:09 GMT"
}
] | 2008-09-22T00:00:00 | [
[
"Srinivasan",
"Shivratna Giri",
""
],
[
"Varanasi",
"Mahesh K.",
""
]
] |
0706.3711 | Karl Rubin | K. Rubin and A. Silverberg | Point counting on reductions of CM elliptic curves | Minor corrections. To appear in Journal of Number Theory | null | 10.1016/j.jnt.2009.01.020 | null | math.NT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give explicit formulas for the number of points on reductions of elliptic
curves with complex multiplication by any imaginary quadratic field. We also
find models for CM $\mathbf{Q}$-curves in certain cases. This generalizes
earlier results of Gross, Stark, and others.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 21:14:08 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jun 2008 23:56:40 GMT"
},
{
"version": "v3",
"created": "Wed, 21 Jan 2009 03:08:42 GMT"
},
{
"version": "v4",
"created": "Thu, 6 Aug 2009 04:48:29 GMT"
}
] | 2009-08-06T00:00:00 | [
[
"Rubin",
"K.",
""
],
[
"Silverberg",
"A.",
""
]
] |
0706.3712 | Yuri Lvov | Yuri V. Lvov, Kurt L. Polzin, Naoto Yokoyama | Resonant and Near-Resonant Internal Wave Interactions | null | Journal of Physical Oceanography, 669-691, 42, (2012) | null | null | physics.flu-dyn physics.ao-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We report evaluations of a resonant kinetic equation that suggest the slow
time evolution of the Garrett and Munk spectrum is {\em not}, in fact, slow.
Instead nonlinear transfers lead to evolution time scales that are smaller than
one wave period at high vertical wavenumber. Such values of the transfer rates
are inconsistent with conventional wisdom that regards the Garrett and Munk
spectrum as an approximate stationary state and puts the self-consistency of a
resonant kinetic equation at a serious risk. We explore possible reasons for
and resolutions of this paradox. Inclusion of near-resonant interactions
decreases the rate at which the spectrum evolves. This leads to improved
self-consistency of the kinetic equation.
| [
{
"version": "v1",
"created": "Tue, 26 Jun 2007 13:29:16 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jun 2008 15:51:51 GMT"
},
{
"version": "v3",
"created": "Thu, 2 Sep 2010 20:09:39 GMT"
},
{
"version": "v4",
"created": "Tue, 7 Sep 2010 16:20:12 GMT"
}
] | 2020-06-05T00:00:00 | [
[
"Lvov",
"Yuri V.",
""
],
[
"Polzin",
"Kurt L.",
""
],
[
"Yokoyama",
"Naoto",
""
]
] |
0706.3713 | Ashish Orpe | Qing Xu, Ashish V. Orpe, and Arshad Kudrolli | Lubrication effects on the flow of wet granular materials | 7 pages, 8 figures | Phys. Rev. E, 76, 031302 (2007) | 10.1103/PhysRevE.76.031302 | null | cond-mat.soft | null | We investigate the dynamics of a partially saturated grain-liquid mixture
with a rotating drum apparatus. The drum is partially filled with the mixture
and then rotated about its horizontal axis. We focus on the continous
avalanching regime and measure the impact of volume fraction and viscosity of
the liquid on the dynamic surface angle. The inclination angle of the surface
is observed to increase sharply to a peak and then decrease as a function of
liquid volume fraction. The height of the peak is observed to increase with
rotation rate. For higher liquid volume fractions, the inclination angle of the
surface can decrease with viscosity before increasing. The viscosity where the
minima occurs decreases with the rotation rate of the drum. Limited
measurements of the flow depth were made, and these were observed to show only
fractional changes with volume fraction and rotation speeds. We show that the
qualitative features of our observations can be understood by analyzing the
effect of lubrication forces on the timescale over which particles come in
contact.
| [
{
"version": "v1",
"created": "Mon, 25 Jun 2007 21:19:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Xu",
"Qing",
""
],
[
"Orpe",
"Ashish V.",
""
],
[
"Kudrolli",
"Arshad",
""
]
] |
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