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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.0314 | Binoy Talukdar None | Amitava Choudhuri, B. Talukdar and U. Das | Lagrangian Approach to Dispersionless KdV Hierarchy | Published in SIGMA (Symmetry, Integrability and Geometry: Methods and
pplications) at http://www.emis.de/journals/SIGMA/ | SIGMA 3 (2007), 096, 11 pages | 10.3842/SIGMA.2007.096 | null | nlin.SI | null | We derive a Lagrangian based approach to study the compatible Hamiltonian
structure of the dispersionless KdV and supersymmetric KdV hierarchies and
claim that our treatment of the problem serves as a very useful supplement of
the so-called r-matrix method. We suggest specific ways to construct results
for conserved densities and Hamiltonian operators. The Lagrangian formulation,
via Noether's theorem, provides a method to make the relation between
symmetries and conserved quantities more precise. We have exploited this fact
to study the variational symmetries of the dispersionless KdV equation.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 11:05:05 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 08:57:55 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Oct 2007 11:16:08 GMT"
}
] | 2008-04-25T00:00:00 | [
[
"Choudhuri",
"Amitava",
""
],
[
"Talukdar",
"B.",
""
],
[
"Das",
"U.",
""
]
] |
0706.0315 | Tien Quang Nguyen | Nguyen Tien Quang, Nguyen Thu Thuy | Ring extension problem, Shukla cohomology and Ann-category theory | 12 pages | null | null | null | math.CT | null | Every ring extension of $A$ by $R$ induces a pair of group homomorphisms
$\mathcal{L}^{*}:R\to End_\Z(A)/L(A);\mathcal{R}^{*}:R\to End_\Z(A)/R(A),$
preserving multiplication, satisfying some certain conditions. A such 4-tuple
$(R,A,\mathcal{L}^{*},\mathcal{R}^{*})$ is called a ring pre-extension. Each
ring pre-extension induces a $R$-bimodule structure on bicenter $K_A$ of ring
$A,$ and induces an obstruction $k,$ which is a 3-cocycle of $\Z$-algebra $R,$
with coefficients in $R$-bimodule $K_A$ in the sense of Shukla. Each
obstruction $k$ in this sense induces a structure of a regular Ann-category of
type $(R,K_A).$ This result gives us the first application of Ann-category in
extension problems of algebraic structures, as well as in cohomology theories.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 11:15:16 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Quang",
"Nguyen Tien",
""
],
[
"Thuy",
"Nguyen Thu",
""
]
] |
0706.0316 | Noriko Shiiki | Muneto Nitta and Noriko Shiiki | Skyrme Strings | 7 pages, 3 figures, references added | Prog.Theor.Phys.119:829-838,2008 | 10.1143/PTP.119.829 | null | hep-ph astro-ph hep-th nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct nontopological string solutions with U(1) Noether charge in the
Skyrme model with a pion mass term, and examine their stability by taking
linear perturbations. The solution exhibits a critical angular velocity beyond
which the configuration energetically prefers to decay by emitting pions. This
critical point is observed as a cusp in the relation between energy and charge.
We find that the maximum length for the string to be stable is comparable to
the size of one skyrmion. Beyond the length, it is unstable to decay. This
instability raises the possiblity of dynamical realization of Skyrme strings
from monopole strings inside a domain wall.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 12:25:21 GMT"
},
{
"version": "v2",
"created": "Thu, 14 Jun 2007 11:28:32 GMT"
},
{
"version": "v3",
"created": "Wed, 10 Sep 2008 12:31:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Nitta",
"Muneto",
""
],
[
"Shiiki",
"Noriko",
""
]
] |
0706.0317 | Pushkar Vaidya | Pushkar Ganesh Vaidya | Are We Alone in the Multiverse? | 4 pages, no figure | Published in the Astrobiology Newsletter, Vol 3, No.4, May 2007,
Bangalore, India | null | null | physics.gen-ph | null | It has long been proposed that black hole singularities bounce to deliver
daughter universes. Here the consequences of such a scenario are explored in
light of Lee Smolin's hypothesis of Cosmological Natural Selection and Weak
Anthropic Principle. The explorations lead towards the answer to the question
Are We Alone in the Multiverse?
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 12:36:53 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Vaidya",
"Pushkar Ganesh",
""
]
] |
0706.0318 | Ying-Qiu Gu | Ying-Qiu Gu | Exact Vacuum Solutions to the Einstein Equation | 11 pages, no figures, submitted to Chinese Annals of Mathematics | Chin. Ann. Math. 28B(5), 2007, 499-506 | 10.1007/s11404-007-0237-5 | null | physics.gen-ph | null | In this paper, we present a framework for getting a series of exact vacuum
solutions to the Einstein equation. This procedure of resolution is based on a
canonical form of the metric. According to this procedure, the Einstein
equation can be reduced to some 2-dimensional Laplace-like equations or
rotation and divergence equations, which are much convenient for the
resolution.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 12:48:57 GMT"
},
{
"version": "v2",
"created": "Sun, 17 Jun 2007 12:50:17 GMT"
}
] | 2007-10-01T00:00:00 | [
[
"Gu",
"Ying-Qiu",
""
]
] |
0706.0319 | Jakob Kellner | Jakob Kellner | Even more simple cardinal invariants | a few changes (minor corrections) from first version | Arch. Math. Logic 47 (2008), No. 5, 503--515 | 10.1007/s00153-008-0094-2 | null | math.LO | null | Using GCH, we force the following: There are continuum many simple cardinal
characteristics with pairwise different values.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 13:01:04 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 18:47:51 GMT"
}
] | 2011-01-25T00:00:00 | [
[
"Kellner",
"Jakob",
""
]
] |
0706.0320 | Jianda Wu | Mei-sheng Zhao, Jian-da Wu, Jian-lan Chen and Yong-de Zhang | Properties of Geometric Potential in the Invariant Adiabatic Theory | 4 pages, 6 figures | null | null | null | quant-ph | null | We concentrate on the geometric potential in the invariant perturbation
theory of quantum adiabatic process which is presented in our recent papers. It
is found out to be related to the geodesic curvature of the spherical curve in
2-dimension quantum systems. We also show that the geometric potential may
affect adiabatic approximation remarkably.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 13:41:31 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Jun 2007 11:10:35 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Zhao",
"Mei-sheng",
""
],
[
"Wu",
"Jian-da",
""
],
[
"Chen",
"Jian-lan",
""
],
[
"Zhang",
"Yong-de",
""
]
] |
0706.0321 | Ryusuke Ikeda | Ryusuke Ikeda | High field superconducting phase diagrams including
Fulde-Ferrell-Larkin-Ovchinnikov vortex states | A reference was updated. To appear in Phys. Rev. B | null | 10.1103/PhysRevB.76.134504 | null | cond-mat.supr-con | null | Motivated by a striking observation of a Fulde-Ferell-Larkin-Ovchinnikov
(FFLO) vortex state in the heavy fermion material CeCoIn5 in fields {\it
perpendicular} to the superconducting planes (${\bf H} \parallel c$),
superconducting phase diagrams including an FFLO state of quasi two-dimensional
(Q2D) superconductors are systematically studied. In the clean {\it limit}, the
high field superconducting state in the low temperature limit should be not the
FFLO state modulating along ${\bf H}$, appeared in CeCoIn5 in both ${\bf H}
\parallel c$ and ${\bf H} \perp c$, but a different vortex state with a
modulation, induced by the paramagnetism, perpendicular to the field. It is
found that the presence of weak impurities is the origin of the absence in
CeCoIn5 of the latter state and leads to the ${\bf H} \parallel c$ phase
diagram, as seen in CeCoIn5, {\it apparently} different in character from that
in ${\bf H} \perp c$.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 14:31:36 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 07:07:07 GMT"
},
{
"version": "v3",
"created": "Sat, 8 Sep 2007 08:50:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ikeda",
"Ryusuke",
""
]
] |
0706.0322 | David Ben-Zvi | David Ben-Zvi, David Nadler | Loop Spaces and Langlands Parameters | Preliminary version. Comments welcome! | null | null | null | math.RT math.AG math.QA | null | We apply the technique of S^1-equivariant localization to sheaves on loop
spaces in derived algebraic geometry, and obtain a fundamental link between two
families of categories at the heart of geometric representation theory. Namely,
we categorify the well known relationship between free loop spaces, cyclic
homology and de Rham cohomology to recover the category of D-modules on a
smooth stack X as a localization of the category of S^1-equivariant coherent
sheaves on its loop space LX. The main observation is that this procedure
connects categories of equivariant D-modules on flag varieties with categories
of equivariant coherent sheaves on the Steinberg variety and its relatives.
This provides a direct connection between the geometry of finite and affine
Hecke algebras and braid groups, and a uniform geometric construction of all of
the categorical parameters for representations of real and complex reductive
groups. This paper forms the first step in a project to apply the geometric
Langlands program to the complex and real local Langlands programs, which we
describe.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 14:41:46 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Ben-Zvi",
"David",
""
],
[
"Nadler",
"David",
""
]
] |
0706.0323 | N. Raj Rao | N. Raj Rao and Roland Speicher | Multiplication of free random variables and the S-transform: the case of
vanishing mean | Submitted to the Electronic Communications on Probability | null | null | null | math.OA cs.IT math.IT math.PR | null | This note extends Voiculescu's S-transform based analytical machinery for
free multiplicative convolution to the case where the mean of the probability
measures vanishes. We show that with the right interpretation of the
S-transform in the case of vanishing mean, the usual formula makes perfectly
good sense.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:10:27 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Rao",
"N. Raj",
""
],
[
"Speicher",
"Roland",
""
]
] |
0706.0324 | Ivan Protopopov V. | I.V. Protopopov and M.V. Feigel'man | Superconductor-insulator duality for the array of Josephson wires | 5 pages, 2 figures | null | 10.1134/S0021364007100098 | null | cond-mat.supr-con cond-mat.mes-hall | null | We propose novel model system for the studies of superconductor-insulator
transitions, which is a regular lattice, whose each link consists of
Josephson-junction chain of $N \gg 1$ junctions in sequence. The theory of such
an array is developed for the case of semiclassical junctions with the
Josephson energy $E_J$ large compared to the junctions's Coulomb energy $E_C$.
Exact duality transformation is derived, which transforms the Hamiltonian of
the proposed model into a standard Hamiltonian of JJ array. The nature of the
ground state is controlled (in the absence of random offset charges) by the
parameter $q \approx N^2 \exp(-\sqrt{8E_J/E_C})$, with superconductive state
corresponding to small $q < q_c $. The values of $q_c$ are calculated for
magnetic frustrations $f= 0$ and $f= \frac12$. Temperature of superconductive
transition $T_c(q)$ and $q < q_c$ is estimated for the same values of $f$. In
presence of strong random offset charges, the T=0 phase diagram is controlled
by the parameter $\bar{q} = q/\sqrt{N}$; we estimated critical value
$\bar{q}_c$.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 14:48:57 GMT"
}
] | 2022-06-01T00:00:00 | [
[
"Protopopov",
"I. V.",
""
],
[
"Feigel'man",
"M. V.",
""
]
] |
0706.0325 | Gui-Jun Ding | Gui-Jun Ding, Mu-Lin Yan | Signals of Unparticles in Low Energy Parity Violation and NuTeV
Experiment | 19 pages, 7 figures | Phys.Rev.D78:075015,2008 | 10.1103/PhysRevD.78.075015 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We have studied the possible signals of unparticle in atomic parity
violation(APV) along an isotope chain and in the NuTeV experiment. The effects
of unparticle physics could be observed in APV, if the uncertainty in relative
neutron/proton radius shift $\delta(\Delta\frac{R_N}{R_P})$ is less than a few
times $10^{-4}$ by measuring the parity violating electron scattering. The
constraints imposed by NuTeV experiment on unparticle physics are discussed in
detail. If the NuTeV results are confirmed by future experiments, we suggest
that unparticle could account for a part of NuTeV anomaly. There exist certain
regions for the unparticle parameters ($\Lambda_{\cal U}$, $d_{\cal U}$,
$c_{V{\cal U}}$ and $c_{A{\cal U}}$), where the NuTeV discrepancy could be
completely explained by unparticle effects and the strange quark asymmetry,
even with or without the contributions from the isoscalarity violation etc. It
is remarkable that these parameter regions are consistent with the constraints
from $b\to s\gamma$
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 15:41:53 GMT"
},
{
"version": "v2",
"created": "Sat, 8 Dec 2007 18:29:36 GMT"
},
{
"version": "v3",
"created": "Tue, 7 Oct 2008 00:52:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ding",
"Gui-Jun",
""
],
[
"Yan",
"Mu-Lin",
""
]
] |
0706.0326 | Jing-Mei Qiu | Jing-Mei Qiu (1), Chi-Wang Shu (1), Ji-Ren Liu (2), Li-Zhi Fang (2)
((1) Division of Applied Mathematics, Brown University, (2) Department of
Physics, University of Arizona) | A WENO Algorithm for the Growth of Ionized Regions at the Reionization
Epoch | Elsart Latex file, 24 pages, 11 figures included, accepted for
publication in New Astronomy | null | 10.1016/j.newast.2007.06.002 | null | astro-ph | null | We investigate the volume growth of ionized regions around UV photon sources
with the WENO algorithm, which is an effective solver of photon kinetics in the
phase space described by the radiative transfer equation. We show that the
volume growth rate, either of isolated ionized regions or of clustered regions
in merging, generally consists of three phases: fast or relativistic growth
phase at the early stage, slow growth phase at the later stage, and a
transition phase between the fast and slow phases. We also show that the volume
growth of ionized regions around clustered sources with intensity $\dot{E}_i$
($i=1, 2, ...$) would have the same behavior as a single source with intensity
$\dot{E}=\sum_i\dot{E}_i$, if all the distances between nearest neighbor
sources $i$ and $j$ are smaller than $c(t^i_c+t^j_c)$, $t^i_c$ being the time
scale $t_c$ of source $i$. Therefore, a tightly clustered UV photon sources
would lead to a slow growth of ionized volume. This effect would be important
for studying the redshift-dependence of 21cm signals from the reionization
epoch.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 15:47:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Qiu",
"Jing-Mei",
""
],
[
"Shu",
"Chi-Wang",
""
],
[
"Liu",
"Ji-Ren",
""
],
[
"Fang",
"Li-Zhi",
""
]
] |
0706.0327 | Zahra-Sadat Yamani | Z. Yamani, W.J.L. Buyers, F. Wang, Y.-J. Kim, R. Liang, D. Bonn, W.N.
Hardy | Antiferromagnetic correlations near the lower edge of superconducting
dome in YBCO6+x | In press Physica C 2007 (proceedings of M2S Conference, Dresden 2006) | Physica C 460--462 (2007) 430--431 | 10.1016/j.physc.2007.03.110 | null | cond-mat.supr-con cond-mat.str-el | null | Neutron scattering from high-quality YBCO6.334 single crystals with a T$_c$
of 8.4 K shows that there is no coexistence with long-range antiferromagnetic
order at this very low, near-critical doping of $\sim$0.055, in contrast to
claims based on local probe techniques. We find that the neutron resonance seen
in optimally doped YBCO7 and underdoped YBCO6.5, has undergone large softening
and damping. It appears that the overdamped resonance, with a relaxation rate
of 2 meV, is coupled to a zero-energy central mode that grows with cooling and
eventually saturates with no change at or below T$_c$. Although a similar
qualitative behaviour is found for YBCO6.35, our study shows that the central
mode is stronger in YBCO6.334 than YBCO6.35. The system remains subcritical
with short-ranged three dimensional correlations.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 15:54:33 GMT"
}
] | 2007-08-29T00:00:00 | [
[
"Yamani",
"Z.",
""
],
[
"Buyers",
"W. J. L.",
""
],
[
"Wang",
"F.",
""
],
[
"Kim",
"Y. -J.",
""
],
[
"Liang",
"R.",
""
],
[
"Bonn",
"D.",
""
],
[
"Hardy",
"W. N.",
""
]
] |
0706.0328 | Hui Wang | Hui Wang, Harvey Gould, and W. Klein | Homogeneous and heterogeneous nucleation of Lennard-Jones liquids | 22 pages, 15 figures | Phys. Rev. E, 76, 031604, 2007 | 10.1103/PhysRevE.76.031604 | null | cond-mat.stat-mech | null | The homogeneous and heterogeneous nucleation of a Lennard-Jones liquid is
investigated using the umbrella sampling method. The free energy cost of
forming a nucleating droplet is determined as a function of the quench depth,
and the saddle point nature of the droplets is verified using an intervention
technique. The structure and symmetry of the nucleating droplets is found for a
range of temperatures. We find that for deep quenches the nucleating droplets
become more anisotropic and diffuse with no well defined core or surface. The
environment of the nucleating droplets form randomly stacked hexagonal planes.
This behavior is consistent with a spinodal nucleation interpretation. We also
find that the free energy barrier for heterogeneous nucleation is a minimum
when the lattice spacing of the impurity equals the lattice spacing of the
equilibrium crystalline phase. If the lattice spacing of the impurity is
different, the crystal grows into the bulk instead of wetting the impurity.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 15:55:46 GMT"
}
] | 2007-10-26T00:00:00 | [
[
"Wang",
"Hui",
""
],
[
"Gould",
"Harvey",
""
],
[
"Klein",
"W.",
""
]
] |
0706.0329 | Doyoon Kim | Doyoon Kim | Parabolic equations with partially VMO coefficients and boundary value
problems in Sobolev spaces with mixed norms | 18 pages | null | null | null | math.AP | null | Second order parabolic equations in Sobolev spaces with mixed norms are
studied. The leading coefficients (except $a^{11}$) are measurable in both time
and one spatial variable, and VMO in the other spatial variables. The
coefficient $a^{11}$ is measurable in time and VMO in the spatial variables.
The unique solvability of equations in the whole space is applied to solving
Dirichlet and oblique derivative problems for parabolic equations defined in a
half-space.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 16:17:01 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Kim",
"Doyoon",
""
]
] |
0706.0330 | John Landstreet | J. D. Landstreet, S. Bagnulo, V. Andretta, L. Fossati, E. Mason, J.
Silaj, G. A. Wade | Searching for links between magnetic fields and stellar evolution. II.
The evolution of magnetic fields as revealed by observations of Ap stars in
open clusters and associations | Accepted by Astronomy & Astrophysics | null | 10.1051/0004-6361:20077343 | null | astro-ph | null | The evolution of magnetic fields in Ap stars during the main sequence phase
is presently mostly unconstrained by observation because of the difficulty of
assigning accurate ages to known field Ap stars.
We are carrying out a large survey of magnetic fields in cluster Ap stars
with the goal of obtaining a sample of these stars with well-determined ages.
In this paper we analyse the information available from the survey as it
currently stands.
We select from the available observational sample the stars that are probably
(1) cluster or association members and (2) magnetic Ap stars. For the stars in
this subsample we determine the fundamental parameters T_eff, log(L/L_o), and
M/M_o. With these data and the cluster ages we assign both absolute age and
fractional age (the fraction of the main sequence lifetime completed). For this
purpose we have derived new bolometric corrections for Ap stars.
Magnetic fields are present at the surfaces of Ap stars from the ZAMS to the
TAMS. Statistically for the stars with M > 3 M_o the fields decline with
advancing age approximately as expected from flux conservation together with
increased stellar radius, or perhaps even faster than this rate, on a time
scale of about 3 10^7 yr. In contrast, lower mass stars show no compelling
evidence for field decrease even on a timescale of several times 10^8 yr.
Study of magnetic cluster stars is now a powerful tool for obtaining
constraints on evolution of Ap stars through the main sequence. Enlarging the
sample of known cluster magnetic stars, and obtaining more precise RMS fields,
will help to clarify the results obtained so far. Further field observations
are in progress.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 16:21:30 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Landstreet",
"J. D.",
""
],
[
"Bagnulo",
"S.",
""
],
[
"Andretta",
"V.",
""
],
[
"Fossati",
"L.",
""
],
[
"Mason",
"E.",
""
],
[
"Silaj",
"J.",
""
],
[
"Wade",
"G. A.",
""
]
] |
0706.0331 | Fei Lin | Fei Lin, Erik S. S{\o}rensen, Catherine Kallin, and A. John Berlinsky | Extended Hubbard model on a C$_{20}$ molecule | 9 pages, 8 figures, 4 tables | J. Phys.: Condens. Matter 19, 456206 (2007) | 10.1088/0953-8984/19/45/456206 | null | cond-mat.str-el cond-mat.supr-con | null | The electronic correlations on a C$_{20}$ molecule, as described by an
extended Hubbard Hamiltonian with a nearest neighbor Coulomb interaction of
strength $V$, are studied using quantum Monte Carlo and exact diagonalization
methods. For electron doped C$_{20}$, it is known that pair-binding arising
from a purely electronic mechanism is absent within the standard Hubbard model
(V=0). Here we show that this is also the case for hole doping for $0<U/t\leq
3$ and that, for both electron and hole doping, the effect of a non-zero $V$ is
to work against pair-binding. We also study the magnetic properties of the
neutral molecule, and find transitions between spin singlet and triplet ground
states for either fixed $U$ or $V$ values. In addition, spin, charge and
pairing correlation functions on C$_{20}$ are computed. The spin-spin and
charge-charge correlations are very short-range, although a weak enhancement in
the pairing correlation is observed for a distance equal to the molecular
diameter.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 16:41:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lin",
"Fei",
""
],
[
"Sørensen",
"Erik S.",
""
],
[
"Kallin",
"Catherine",
""
],
[
"Berlinsky",
"A. John",
""
]
] |
0706.0332 | Jon G. Wolfson | Lei Ni and Jon Wolfson | Positive Complex Sectional Curvature, Ricci Flow and the Differential
Sphere Theorem | null | null | null | null | math.DG | null | The paper provides a different proof of the result of Brendle-Schoen on the
differential sphere theorem. It is shown directly that the invariant cone of
curvature operators with positive (or non-negative) complex sectional curvature
is preserved by the Ricci flow. This implies, by a result of B\"ohm-Wilking,
that the normalized Ricci flow deforms such a metric to a metric of constant
positive curvature. Using earlier work of Yau and Zheng it can be shown that a
metric with strictly (pointwise) 1/4-pinched sectional curvature has positive
complex sectional curvature. This gives a direct proof of Brendle-Schoen's
recent differential sphere theorem, bypassing any discussion of positive
isotropic curvature.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 16:57:19 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Ni",
"Lei",
""
],
[
"Wolfson",
"Jon",
""
]
] |
0706.0333 | Ashkan Nikeghbali | Paul Bourgade, Chris Hughes, Ashkan Nikeghbali and Marc Yor | The characteristic polynomial of a random unitary matrix: a
probabilistic approach | null | null | null | null | math.PR math-ph math.MP | null | In this paper, we propose a probabilistic approach to the study of the
characteristic polynomial of a random unitary matrix. We recover the Mellin
Fourier transform of such a random polynomial, first obtained by Keating and
Snaith, using a simple recursion formula, and from there we are able to obtain
the joint law of its radial and angular parts in the complex plane. In
particular, we show that the real and imaginary parts of the logarithm of the
characteristic polynomial of a random unitary matrix can be represented in law
as the sum of independent random variables. From such representations, the
celebrated limit theorem obtained by Keating and Snaith is now obtained from
the classical central limit theorems of Probability Theory, as well as some new
estimates for the rate of convergence and law of the iterated logarithm type
results.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 17:19:28 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Bourgade",
"Paul",
""
],
[
"Hughes",
"Chris",
""
],
[
"Nikeghbali",
"Ashkan",
""
],
[
"Yor",
"Marc",
""
]
] |
0706.0334 | A. Tureanu | Anca Tureanu | Twisted Poincar\'e Symmetry and Some Implications on Noncommutative
Quantum Field Theory | Talk given at the 21st Nishinomiya-Yukawa Memorial Symposium on
Theoretical Physics "Noncommutative Geometry and Quantum Space-Time in
Physics", Nishinomiya-Kyoto, Japan, 11-15 November 2006 | null | 10.1143/PTPS.171.34 | null | hep-th | null | The concept of twisted Poincar\'e symmetry, as well as some implications, are
reviewed. The spin-statistics relation and the nonlocality of NC QFT are
discussed in the light of this quantum symmetry. The possibility of a twisted
symmetry principle for quantum field and gauge theories formulated on a
noncommutative space-time is also explored.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 17:27:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tureanu",
"Anca",
""
]
] |
0706.0335 | Rafik Ballou | Rafik Ballou (NEEL) | Form factors in magnetic scattering of thermal neutrons | Lecture notes (European school on Polarized Neutrons for Material and
Life Sciences, 4th - 7th June 2005, Anglet, France) - 59 pages | null | null | null | cond-mat.other | null | This lecture addresses the concept of form factor in magnetic scattering of
thermal neutrons, analyzing its meaning, discussing its measurement by
polarized neutrons and detailing its computation for the ions by the spherical
tensor operator formalism.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 17:34:44 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Ballou",
"Rafik",
"",
"NEEL"
]
] |
0706.0336 | Gregory Fleishman | Gregory D. Fleishman, Igor N. Toptygin | Diffusive radiation in Langmuir turbulence produced by jet shocks | 9 pages, 5 figures, MNRAS, accepted | null | 10.1111/j.1365-2966.2007.12059.x | null | astro-ph | null | Anisotropic distributions of charged particles including two-stream
distributions give rise to generation of either stochastic electric fields (in
the form of Langmuir waves, Buneman instability) or random quasi-static
magnetic fields (Weibel and filamentation instabilities) or both. These
two-stream instabilities are known to play a key role in collisionless shock
formation, shock-shock interactions, and shock-induced electromagnetic
emission. This paper applies the general non-perturbative stochastic theory of
radiation to study electromagnetic emission produced by relativistic particles,
which random walk in the stochastic electric fields of the Langmuir waves. This
analysis takes into account the cumulative effect of uncorrelated Langmuir
waves on the radiating particle trajectory giving rise to angular diffusion of
the particle, which eventually modifies the corresponding radiation spectra. We
demonstrate that the radiative process considered is probably relevant for
emission produced in various kinds of astrophysical jets, in particular, prompt
gamma-ray burst spectra, including X-ray excesses and prompt optical flashes.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 17:35:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fleishman",
"Gregory D.",
""
],
[
"Toptygin",
"Igor N.",
""
]
] |
0706.0337 | Ali Moosavi | A. Moosavi, M. Rauscher, and S. Dietrich | Motion of nanodroplets near chemical heterogeneities | 6 pages, 6 figures | null | null | null | cond-mat.soft | null | We investigate the dynamics of nanoscale droplets in the vicinity of chemical
steps which separate parts of a substrate with different wettabilities. Due to
long-ranged dispersion forces, nanodroplets positioned on one side of the step
perceive the different character of the other side even at some distances from
the step, leading to a dynamic response. The direction of the ensuing motion of
such droplets does not only depend on the difference between the equilibrium
contact angles on these two parts but in particular on the difference between
the corresponding Hamaker constants. Therefore the motion is not necessarily
directed towards the more wettable side and can also be different from that of
droplets which span the step.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 15:45:53 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Moosavi",
"A.",
""
],
[
"Rauscher",
"M.",
""
],
[
"Dietrich",
"S.",
""
]
] |
0706.0338 | Alan Kadin | Alan M. Kadin | Coherent Lattice Vibrations in Superconductors | 15 pages, 5 figures. Presented at Israel Workshop on Fluctuations and
Phase Transitions in Superconductors, Nazareth Ilit, Israel, June 10-14, 2007 | Physica C 468 (2008) 255-259 | 10.1016/j.physc.2007.08.026 | null | cond-mat.supr-con | null | A recent analysis by Kadin has noted that the superconducting wavefunction
within the BCS theory may be represented in real-space as a spherical
electronic orbital (on the scale of the coherence length) coupled to a
standing-wave lattice vibration. This lattice vibration, effectively a bound
phonon, has wavevector 2kf and a near-resonant frequency (on the order of the
Debye frequency) that maximizes the attractive electrostatic interaction energy
with the electronic orbital. The present paper extends this picture to a
coherent standing-wave pattern of electron and phonon waves that traverses the
entire superconductor on the macroscopic scale. These parallel planes form a
diffractive waveguide for electron waves traveling parallel to the planes,
permitting lossless supercurrent. A similar picture may be extended to
unconventional superconductors such as the cuprates, with an array of standing
spin waves rather than phonons. Such coherent lattice vibrations should be
universal and distinctive indicators of the superconducting state, and should
be observable below Tc using standard x-ray and neutron diffraction techniques.
Further implications of this picture are discussed.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 17:53:07 GMT"
}
] | 2008-03-31T00:00:00 | [
[
"Kadin",
"Alan M.",
""
]
] |
0706.0339 | Stanislav Jabuka | Stanislav Jabuka, Thomas E. Mark | Product Formulae for Ozsvath-Szabo 4-manifold Invariants | 70 pages, 2 figures | Geom. Topol. 12 (2008) 1557-1651 | 10.2140/gt.2008.12.1557 | null | math.GT | null | We give formulae for the Ozsvath-Szabo invariants of 4-manifolds X obtained
by fiber sum of two manifolds M_1, M_2 along surfaces S_1, S_2 having trivial
normal bundle and genus g>0. The formulae follow from a general theorem on the
Ozsvath-Szabo invariants of the result of gluing two 4-manifolds along a common
boundary, which is phrased in terms of relative invariants of the pieces. These
relative invariants take values in a version of Heegaard Floer homology with
coefficients in modules over certain Novikov rings; the fiber sum formula
follows from the theorem that this "perturbed" version of Heegaard Floer theory
recovers the usual Ozsvath-Szabo invariants, when the 4-manifold in question
has b^+>1. The construction allows an extension of the definition of the
Ozsvath-Szabo invariants to 4-manifolds having b^+ = 1 depending on certain
choices, in close analogy with Seiberg-Witten theory. The product formulae lead
quickly to calculations of the Ozsvath-Szabo invariants of various 4-manifolds;
in all cases the results are in accord with the conjectured equivalence between
the Ozsvath-Szabo and Seiberg-Witten invariants.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 19:20:48 GMT"
}
] | 2016-01-20T00:00:00 | [
[
"Jabuka",
"Stanislav",
""
],
[
"Mark",
"Thomas E.",
""
]
] |
0706.0340 | Nicolas Boulanger | Nicolas Boulanger | Algebraic Classification of Weyl Anomalies in Arbitrary Dimensions | 4 pages - accepted for publication in Physical Review Letters | Phys.Rev.Lett.98:261302,2007 | 10.1103/PhysRevLett.98.261302 | null | hep-th | null | Conformally invariant massless field systems involving only dimensionless
parameters are known to describe particle physics at very high energy. In the
presence of an external gravitational field, the conformal symmetry may
generalize to Weyl invariance. However, the latter symmetry no longer survives
after quantization: A Weyl anomaly appears. In this Letter, a purely algebraic
understanding of the universal structure of the Weyl anomalies is presented.
The results hold in arbitrary dimensions and independently of any
regularization scheme.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 18:58:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Boulanger",
"Nicolas",
""
]
] |
0706.0341 | Giambattista Giacomin | Giambattista Giacomin | Renewal convergence rates and correlation decay for homogeneous pinning
models | 13 pages | null | null | null | math.PR math-ph math.MP | null | A class of discrete renewal processes with super-exponentially decaying
inter-arrival distributions coincides with the infinite volume limit of general
homogeneous pinning models in their localized phase. Pinning models are
statistical mechanics systems to which a lot of attention has been devoted both
for their relevance for applications and because they are solvable models
exhibiting a non-trivial phase transition. The spatial decay of correlations in
these systems is directly mapped to the speed of convergence to equilibrium for
the associated renewal processes. We show that close to criticality, under
general assumptions, the correlation decay rate, or the renewal convergence
rate, coincides with the inter-arrival decay rate. We also show that, in
general, this is false away from criticality. Under a stronger assumption on
the inter-arrival distribution we establish a local limit theorem, capturing
thus the sharp asymptotic behavior of correlations.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 19:30:33 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Giacomin",
"Giambattista",
""
]
] |
0706.0342 | Paola Cappellaro | Paola Cappellaro, Chandrasekhar Ramanathan, David G. Cory | Simulations of Information Transport in Spin Chains | null | Phys. Rev. A 76, 032317 (2007) | 10.1103/PhysRevLett.99.250506 | null | quant-ph | null | Transport of quantum information in linear spin chains has been the subject
of much theoretical work. Experimental studies by nuclear spin systems in
solid-state by NMR (a natural implementation of such models) is complicated
since the dipolar Hamiltonian is not solely comprised of nearest-neighbor
XY-Heisenberg couplings. We present here a similarity transformation between
the XY-Heisenberg Hamiltonian and the grade raising Hamiltonian, an interaction
which is achievable with the collective control provided by radio-frequency
pulses in NMR. Not only does this second Hamiltonian allows us to simulate the
information transport in a spin chain, but it also provides a means to observe
its signature experimentally.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 17:22:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cappellaro",
"Paola",
""
],
[
"Ramanathan",
"Chandrasekhar",
""
],
[
"Cory",
"David G.",
""
]
] |
0706.0343 | Mark Coffey | Mark W. Coffey | The Stieltjes constants, their relation to the eta_j coefficients, and
representation of the Hurwitz zeta function | 37 pages, no figures Prop. 3(b) added and minor updates | null | null | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Stieltjes constants gamma_k(a) are the expansion coefficients in the
Laurent series for the Hurwitz zeta function about its only pole at s=1. We
present the relation of gamma_k(1) to the eta_j coefficients that appear in the
Laurent expansion of the logarithmic derivative of the Riemann zeta function
about its pole at s=1. We obtain novel integral representations of the
Stieltjes constants and new decompositions such as S_2(n) = S_gamma(n) +
S_Lambda(n) for the crucial oscillatory subsum of the Li criterion for the
Riemann hypothesis. The sum S_\gamma(n) is O(n) and we present various integral
representations for it. We present novel series representations of S_2(n). We
additionally present a rapidly convergent expression for \gamma_k= \gamma_k(1)
and a variety of results pertinent to a parameterized representation of the
Riemann and Hurwitz zeta functions.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 19:49:52 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Feb 2009 23:36:54 GMT"
}
] | 2009-02-26T00:00:00 | [
[
"Coffey",
"Mark W.",
""
]
] |
0706.0344 | Philippe Thebault | Philippe Thebault, Jean-Charles Augereau | Collisional processes and size distribution in spatially extended debris
discs | Accepted for publication in Astronomy and Astrophysics (with better
figures) (note: full abstract in the *.pdf file) | null | 10.1051/0004-6361:20077709 | null | astro-ph | null | We present a new multi-annulus code for the study of collisionally evolving
extended debris discs. We first aim to confirm results obtained for a
single-annulus system, namely that the size distribution in "real" debris discs
always departs from the theoretical collisional equilibrium
$dN\proptoR^{-3.5}dR$ power law, especially in the crucial size range of
observable particles (<1cm), where it displays a characteristic wavy pattern.
We also aim at studying how debris discs density distributions, scattered light
luminosity profiles, and SEDs are affected by the coupled effect of collisions
and radial mixing due to radiation pressure affected small grains. The size
distribution evolution is modeled from micron-sized grains to 50km-sized
bodies. The model takes into account the crucial influence of radiation
pressure-affected small grains. We consider the collisional evolution of a
fiducial a=120AU radius disc with an initial surface density in
$\Sigma(a)\propto a^{\alpha}$. We show that the system's radial extension plays
a crucial role: in most regions the collisional and size evolution of the dust
is imposed by small particles on eccentric or unbound orbits produced further
inside the disc. The spatial distribution of small grains strongly departs from
the initial profile, while the bigger objects, containing most of the system's
mass, still follow the initial distribution. This has consequences on the
scattered--light radial profiles which get significantly flatter, and we
propose an empirical law to trace back the distribution of large unseen parent
bodies from the observed profiles. We finally provide empirical formula for the
collisional size distribution and collision timescale that can be used for
future debris disc modeling.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 20:01:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Thebault",
"Philippe",
""
],
[
"Augereau",
"Jean-Charles",
""
]
] |
0706.0345 | Mark Coffey | Mark W. Coffey | Series of zeta values, the Stieltjes constants, and a sum S_\gamma(n) | 33 pages, no figures. Prop. 1(b) typos fixed and proof elaborated.
New section with Corollary 1 added. Minor updates | null | null | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a variety of series representations of the Stieltjes and related
constants, the Stieltjes constants being the coefficients of the Laurent
expansion of the Hurwitz zeta function zeta(s,a) about s=1. Additionally we
obtain series and integral representations of a sum S_\gamma(n) formed as an
alternating binomial series from the Stieltjes constants. The slowly varying
sum S_\gamma(n)+n is an important subsum in application of the Li criterion for
the Riemann hypothesis.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 20:04:18 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Feb 2009 23:44:33 GMT"
}
] | 2009-02-26T00:00:00 | [
[
"Coffey",
"Mark W.",
""
]
] |
0706.0346 | Alan Horwitz | Alan Horwitz | Complex Ratios of Cubic Polynomials | null | International Journal of Pure and Applied Mathematics, vol. 33,
No. 1 (2006), 49-62 | null | null | math.CV math.CA | null | Let $p(w)=(w-w_{1})(w-w_{2})(w-w_{3}),$with
$\func{Re}w_{1}<\func{Re}w_{2}<\func{Re}w_{3}$. Assume that if the critical
points of $p$ are not identical, then they cannot have equal real parts. Define
the ratios $\sigma_{1}=\dfrac{z_{1}-w_{1}}{w_{2}-w_{1}}$ and $\sigma
_{2}=\dfrac{z_{2}-w_{2}}{w_{3}-w_{2}}$. $(\sigma_{1},\sigma_{2})$ is called the
\QTR{it}{ratio vector} of $p$. This extends the definition of ratio vectors
given in earlier papers for polynomials of degree $n$ with all real roots. We
then derive bounds on the real part, imaginary part, and modulus of the ratios
and also some relations between the ratios. In particular, we prove that
$\func{Re}\sigma_{1}\leq \func{Re}\sigma_{2}$. We also show that the ratios are
real if and only if the roots of $p$ are collinear.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 20:08:17 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Horwitz",
"Alan",
""
]
] |
0706.0347 | Chris Brook | C. B. Brook, D. Kawata, H. Martel, B. K. Gibson, E. Scannapieco | Chemical and Dynamical Properties of the Stellar Halo | Conference proceedings linked in ADS, 6 short pages | EAS Publ.Ser.24:269-275,2007 | 10.1051/eas:2007036 | null | astro-ph | null | The difference in density profiles of the contributions from different
density peaks to dark matter halos results in certain expectations about the
Milky Way's stellar halo. We cut our simulated halo stars into two populations:
those forming before/during the last major merger, and those accreted after the
last major merger. The former population are more centrally located at z=0,
while stars forming in low mass late forming proto-galaxies are spread through
the halo. A difference in observed binding energy distinguishes these two
populations. We look at possible chemical abundance signatures of the two
populations. We also show that galaxies forming in isolated low sigma peaks
will form from primordial material. Thus, even though the oldest stars are
centrally concentrated as they originated in the early collapsing, densest
regions, primordial stars would be found distributed throughout the halo. Thus,
the lack of observed metal free stars can be taken as directly constraining the
Population III IMF, and the lowest metallicity observed stars can be
interpreted as holding clues to the chemical yields of Pop III stars.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 20:31:50 GMT"
}
] | 2009-03-19T00:00:00 | [
[
"Brook",
"C. B.",
""
],
[
"Kawata",
"D.",
""
],
[
"Martel",
"H.",
""
],
[
"Gibson",
"B. K.",
""
],
[
"Scannapieco",
"E.",
""
]
] |
0706.0348 | Weiqiang Wang | Bin Shu, Weiqiang Wang | Modular representations of the ortho-symplectic supergroups | v2, 23 pages, updated references and minor changes, to appear in
Proc. London Math. Soc | Proc. London Math. Soc. 96 (2008), 251--271. | 10.1112/plms/pdm040 | null | math.RT math.QA | null | A Chevalley type integral basis for the ortho-symplectic Lie superalgebra is
constructed. The simple modules of the ortho-symplectic supergroup over an
algebraically closed field of prime characteristic not equal to 2 are
classified, where a key combinatorial ingredient comes from the Mullineux
conjecture on modular representations of the symmetric group. A Steinberg
tensor product theorem for the ortho-symplectic supergroup is also obtained.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 20:37:30 GMT"
},
{
"version": "v2",
"created": "Sun, 2 Sep 2007 15:51:10 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Shu",
"Bin",
""
],
[
"Wang",
"Weiqiang",
""
]
] |
0706.0349 | Nabanita Dasgupta-Schubert | N. Dasgupta-Schubert (UMSNH), S. Alexander (SWU), L. Sommer (SWU), T.
Whelan (UTPA), R. Alfaro Cuevas Villanueva (UMSNH), M. E. Mendez Lopez
(UMSNH), M. W. Persans (UTPA) | The Light Quanta Modulated Physiological Response of Brassica Juncea
Seedlings Subjected to Ni(II) Stress | 9 pages, 7 figures, PDF file only. Based on a lecture presented by N.
Dasgupta-Schubert at the ISEB/ESEB/JSEB International Symposium on
Environmental Biotechnology in Leipzig, Germany, July 9-13, 2006 | Engineering in the Life Sciences, 7(3), 259-267 (2007) | null | null | q-bio.OT | null | This work is a study of the inter-relationship between parameters that
principally affect metal up-take in the plant. The relationships between the
concentration of metal in the growth medium, Cs, the concentration of metal
absorbed by the plant, Cp, and the total biomass achieved, M, all of which are
factors relevant to the efficiency of phytoremediation of the plant, have been
investigated via the macro-physiological response of Brassica juncea seedlings
to Ni(II) stress. The factorial growth experiments treated the Ni(II)
concentration in the agar gel and the diurnal light quanta (DLQ) as
independently variable parameters. Observations included the evidence of light
enhancement of Ni toxicity at the root as well as at the whole plant level, the
shoot mass index as a possible indicator of shoot metal sequestration in B.
juncea, the logarithmic variation of Cp with Cs and the power-law dependence of
M on Cp. The sum total of these observations indicate that for the metal
accumulator B. juncea with regard to its capacity to accumulate Ni, the overall
metabolic nature of the plant is important; neither rapid biomass increase nor
a high metal concentration capability favor the removal of high metal mass from
the medium, but rather the plant with the moderate photosynthetically driven
biomass growth and moderate metal concentrations demonstrated the ability to
remove the maximum mass of metal from the medium. The implications of these
observations in the context of the perceived need in phytoremediation
engineering to maximize Cp and M simultaneously in the same plant, are
discussed.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 21:00:45 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Dasgupta-Schubert",
"N.",
"",
"UMSNH"
],
[
"Alexander",
"S.",
"",
"SWU"
],
[
"Sommer",
"L.",
"",
"SWU"
],
[
"Whelan",
"T.",
"",
"UTPA"
],
[
"Villanueva",
"R. Alfaro Cuevas",
"",
"UMSNH"
],
[
"Lopez",
"M. E. Mendez",
"",
"UMSNH"
],
[
"Persans",
"M. W.",
"",
"UTPA"
]
] |
0706.0350 | Jean-Francois Bony | Jean-Francois Bony, Dietrich Hafner | Decay and non-decay of the local energy for the wave equation in the De
Sitter - Schwarzschild metric | 22 pages, 5 figures | null | null | null | math.AP math-ph math.MP | null | We describe an expansion of the solution of the wave equation in the De
Sitter - Schwarzschild metric in terms of resonances. The main term in the
expansion is due to a zero resonance. The error term decays polynomially if we
permit a logarithmic derivative loss in the angular directions and
exponentially if we permit an small derivative loss in the angular directions.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:11:35 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Bony",
"Jean-Francois",
""
],
[
"Hafner",
"Dietrich",
""
]
] |
0706.0351 | Sebastian Zwicknagl | Sebastian Zwicknagl | R-Matrix Poisson Algebras and Their Deformations | 50 pages | null | null | null | math.QA math.RT | null | We classify in this paper Poisson structures on modules over semisimple Lie
algebras arising from classical r-matrices. We then study their quantizations
and the relation to classical invariant theory.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 21:13:18 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Zwicknagl",
"Sebastian",
""
]
] |
0706.0352 | Luzh | Jingfu Zhang, Nageswaran Rajendran, Xinhua Peng, and Dieter Suter | Iterative quantum state transfer along a chain of nuclear spin qubits | Version for submission. Comments are welcome | Phys. Rev. A 76, 012317 (2007) | 10.1103/PhysRevA.76.012317 | null | quant-ph | null | Transferring quantum information between two qubits is a basic requirement
for many applications in quantum communication and quantum information
processing. In the iterative quantum state transfer (IQST) proposed by D.
Burgarth et al. [Phys. Rev. A 75, 062327 (2007)], this is achieved by a static
spin chain and a sequence of gate operations applied only to the receiving end
of the chain. The only requirement on the spin chain is that it transfers a
finite part of the input amplitude to the end of the chain, where the gate
operations accumulate the information. For an appropriate sequence of
evolutions and gate operations, the fidelity of the transfer can asymptotically
approach unity. We demonstrate the principle of operation of this transfer
scheme by implementing it in a nuclear magnetic resonance quantum information
processor.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 21:59:28 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 13:17:25 GMT"
},
{
"version": "v3",
"created": "Wed, 18 Jul 2007 06:49:22 GMT"
}
] | 2007-07-18T00:00:00 | [
[
"Zhang",
"Jingfu",
""
],
[
"Rajendran",
"Nageswaran",
""
],
[
"Peng",
"Xinhua",
""
],
[
"Suter",
"Dieter",
""
]
] |
0706.0353 | Douglas Lundholm | Jens Hoppe, Douglas Lundholm | On the Construction of Zero Energy States in Supersymmetric Matrix
Models IV | null | null | null | null | hep-th | null | Simple recursion relations for zero energy states of supersymmetric matrix
models are derived by using an unconventional reducible representation for the
fermionic degrees of freedom.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 22:19:14 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Hoppe",
"Jens",
""
],
[
"Lundholm",
"Douglas",
""
]
] |
0706.0354 | Myriam Mondragon | A. Mondragon, M. Mondragon, E. Peinado (IF-UNAM) | Lepton masses, mixings and FCNC in a minimal S_3-invariant extension of
the Standard Model | One paragraph added with comparison to tri-bimaximal mixing, two
lines changed in abstract, references added, typographical errors corrected | Phys.Rev.D76:076003,2007 | 10.1103/PhysRevD.76.076003 | null | hep-ph | null | The mass matrices of the charged leptons and neutrinos, previously derived in
a minimal S_3-invariant extension of the Standard Model, were reparametrized in
terms of their eigenvalues. We obtained explicit, analytical expressions for
all entries in the neutrino mixing matrix, V_PMNS, the neutrino mixing angles
and the Majorana phases as functions of the masses of charged leptons and
neutrinos in excellent agreement with the latest experimental values. The
resulting V_PMNS matrix is very close to the tri-bimaximal form of the neutrino
mixing matrix. We also derived explicit analytical expressions for the matrices
of the Yukawa couplings and computed the branching ratios of some selected
flavour changing neutral current processes as functions of the masses of the
charged leptons and the neutral Higgs bosons. We find that the S_3 x Z_2
flavour symmetry and the strong mass hierarchy of the charged leptons strongly
suppress the FCNC processes in the leptonic sector well below the present
experimental upper bounds by many orders of magnitude.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 22:35:24 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 18:17:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mondragon",
"A.",
"",
"IF-UNAM"
],
[
"Mondragon",
"M.",
"",
"IF-UNAM"
],
[
"Peinado",
"E.",
"",
"IF-UNAM"
]
] |
0706.0355 | Douglas Lundholm | Volker Bach, Jens Hoppe, Douglas Lundholm | Dynamical Symmetries in Supersymmetric Matrix Models | null | Doc. Math. 13 (2008), 103-116 | null | null | hep-th | null | We reveal a dynamical SU(2) symmetry in the asymptotic description of
supersymmetric matrix models. We also consider a recursive approach for
determining the ground state, and point out some additional properties of the
model(s).
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 22:35:53 GMT"
}
] | 2008-11-12T00:00:00 | [
[
"Bach",
"Volker",
""
],
[
"Hoppe",
"Jens",
""
],
[
"Lundholm",
"Douglas",
""
]
] |
0706.0356 | David M. Bradley | David M. Bradley | A class of series acceleration formulae for Catalan's constant | 13 pages, AMSLaTeX | Ramanujan Journal Vol. 3 (1999), no. 2, pp. 159--173. [MR 1703281]
(2000f:11163) | 10.1023/A:1006945407723 | null | math.CA math.NT | null | In this note, we develop transformation formulae and expansions for the log
tangent integral, which are then used to derive series acceleration formulae
for certain values of Dirichlet L-functions, such as Catalan's constant. The
formulae are characterized by the presence of an infinite series whose general
term consists of a linear recurrence damped by the central binomial coefficient
and a certain quadratic polynomial. Typically, the series can be expressed in
closed form as a rational linear combination of Catalan's constant and pi times
the logarithm of an algebraic unit.
| [
{
"version": "v1",
"created": "Sun, 3 Jun 2007 23:29:15 GMT"
}
] | 2010-05-25T00:00:00 | [
[
"Bradley",
"David M.",
""
]
] |
0706.0357 | Hisanobu Shinya | Hisanobu Shinya | A certain continuity property of the residues of the poles of $\sum_{n
\geq 1} \Lambda(n) e^{-2 \pi i q n } n^{-s}$ with respect to $q \in
\mathbb{Q} \cap (0, 1)$ and the Riemann hypothesis | 13 pages. An ambiguity at the equation (20) in summing with respect
to $x$ was clarified. The correction is an easy one (simply replace $e^{- \pi
i q n}$ by $e^{-2 \pi i q n}$), but is very important because it concerns
about stating $A(a, b; \chi)$ correctly and calculating it | null | null | null | math.GM | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The purpose of this article is to present some result which may characterize
nontrivial zeros of the Riemann zeta-function off the critical line
$\text{Re}(s) = 1/2$, if any exists. In brief, it concerns the residues of the
poles of the function $M(s, q) \equiv \sum_{n \geq 1} \Lambda(n) e^{- 2\pi i q
n } n^{-s}$, where $\Lambda$ is the arithmetical Mangoldt $\Lambda$-function.
Suppose that $M(s, 1/2)$ has a pole for some complex number $\rho_{*}$, with
$\text{Re}(\rho_{*}) > 1/2$. Then we discuss a certain continuity property of
the residues of the poles of $M(\rho_{*}, q)$ with respect to the variable $q
\in \mathbb{Q} \cap (1/2, 1)$.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:48:54 GMT"
},
{
"version": "v10",
"created": "Mon, 12 Jul 2010 02:01:53 GMT"
},
{
"version": "v11",
"created": "Wed, 21 Jul 2010 13:16:39 GMT"
},
{
"version": "v12",
"created": "Thu, 22 Jul 2010 05:53:53 GMT"
},
{
"version": "v13",
"created": "Mon, 26 Jul 2010 03:41:03 GMT"
},
{
"version": "v14",
"created": "Wed, 28 Jul 2010 04:00:26 GMT"
},
{
"version": "v15",
"created": "Fri, 27 Aug 2010 15:08:40 GMT"
},
{
"version": "v16",
"created": "Mon, 30 Aug 2010 01:21:24 GMT"
},
{
"version": "v17",
"created": "Fri, 3 Sep 2010 13:55:30 GMT"
},
{
"version": "v18",
"created": "Mon, 13 Sep 2010 14:47:51 GMT"
},
{
"version": "v19",
"created": "Wed, 15 Sep 2010 03:47:18 GMT"
},
{
"version": "v2",
"created": "Sun, 1 Jul 2007 13:36:57 GMT"
},
{
"version": "v20",
"created": "Thu, 23 Sep 2010 18:02:41 GMT"
},
{
"version": "v21",
"created": "Wed, 29 Sep 2010 00:09:45 GMT"
},
{
"version": "v22",
"created": "Fri, 1 Oct 2010 09:09:02 GMT"
},
{
"version": "v23",
"created": "Mon, 25 Oct 2010 01:26:51 GMT"
},
{
"version": "v24",
"created": "Mon, 1 Nov 2010 05:10:34 GMT"
},
{
"version": "v25",
"created": "Mon, 8 Nov 2010 02:13:58 GMT"
},
{
"version": "v26",
"created": "Sat, 20 Nov 2010 01:49:48 GMT"
},
{
"version": "v27",
"created": "Wed, 22 Dec 2010 02:30:44 GMT"
},
{
"version": "v28",
"created": "Mon, 31 Jan 2011 08:13:24 GMT"
},
{
"version": "v29",
"created": "Fri, 4 Mar 2011 20:18:11 GMT"
},
{
"version": "v3",
"created": "Sun, 16 Dec 2007 10:56:29 GMT"
},
{
"version": "v30",
"created": "Fri, 1 Apr 2011 17:26:20 GMT"
},
{
"version": "v31",
"created": "Mon, 4 Jul 2011 21:54:21 GMT"
},
{
"version": "v32",
"created": "Thu, 21 Jul 2011 02:57:22 GMT"
},
{
"version": "v33",
"created": "Sat, 13 Aug 2011 00:22:07 GMT"
},
{
"version": "v34",
"created": "Sun, 11 Sep 2011 00:46:54 GMT"
},
{
"version": "v35",
"created": "Mon, 26 Mar 2012 21:42:07 GMT"
},
{
"version": "v36",
"created": "Sun, 27 May 2012 00:35:38 GMT"
},
{
"version": "v37",
"created": "Thu, 31 May 2012 12:15:44 GMT"
},
{
"version": "v38",
"created": "Wed, 20 Jun 2012 12:43:42 GMT"
},
{
"version": "v39",
"created": "Thu, 6 Sep 2012 12:42:55 GMT"
},
{
"version": "v4",
"created": "Wed, 26 Dec 2007 13:10:27 GMT"
},
{
"version": "v40",
"created": "Thu, 13 Dec 2012 09:34:36 GMT"
},
{
"version": "v41",
"created": "Tue, 18 Dec 2012 01:44:09 GMT"
},
{
"version": "v42",
"created": "Mon, 14 Jan 2013 12:48:13 GMT"
},
{
"version": "v43",
"created": "Sun, 17 Mar 2013 12:04:45 GMT"
},
{
"version": "v44",
"created": "Fri, 2 Aug 2013 03:11:54 GMT"
},
{
"version": "v45",
"created": "Fri, 29 Nov 2013 11:51:47 GMT"
},
{
"version": "v46",
"created": "Wed, 15 Jul 2015 02:42:50 GMT"
},
{
"version": "v47",
"created": "Fri, 17 Jul 2015 07:07:32 GMT"
},
{
"version": "v48",
"created": "Sat, 25 Jul 2015 13:07:15 GMT"
},
{
"version": "v49",
"created": "Wed, 19 Aug 2015 11:02:14 GMT"
},
{
"version": "v5",
"created": "Tue, 5 Aug 2008 10:06:18 GMT"
},
{
"version": "v50",
"created": "Sat, 29 Aug 2015 02:05:38 GMT"
},
{
"version": "v51",
"created": "Wed, 9 Sep 2015 04:49:53 GMT"
},
{
"version": "v52",
"created": "Thu, 17 Sep 2015 11:26:07 GMT"
},
{
"version": "v53",
"created": "Wed, 23 Sep 2015 03:26:46 GMT"
},
{
"version": "v54",
"created": "Tue, 29 Sep 2015 07:32:07 GMT"
},
{
"version": "v55",
"created": "Thu, 15 Oct 2015 07:17:10 GMT"
},
{
"version": "v56",
"created": "Mon, 16 Nov 2015 08:41:44 GMT"
},
{
"version": "v57",
"created": "Mon, 7 Dec 2015 07:50:52 GMT"
},
{
"version": "v58",
"created": "Mon, 14 Dec 2015 06:38:54 GMT"
},
{
"version": "v59",
"created": "Sun, 10 Jan 2016 10:37:35 GMT"
},
{
"version": "v6",
"created": "Fri, 8 Aug 2008 00:00:23 GMT"
},
{
"version": "v60",
"created": "Fri, 29 Dec 2017 04:03:57 GMT"
},
{
"version": "v61",
"created": "Sun, 28 Jan 2018 00:48:18 GMT"
},
{
"version": "v62",
"created": "Fri, 23 Mar 2018 08:09:36 GMT"
},
{
"version": "v63",
"created": "Tue, 27 Nov 2018 16:55:29 GMT"
},
{
"version": "v64",
"created": "Mon, 11 Feb 2019 04:07:40 GMT"
},
{
"version": "v65",
"created": "Sun, 14 May 2023 15:15:00 GMT"
},
{
"version": "v66",
"created": "Mon, 29 May 2023 08:42:46 GMT"
},
{
"version": "v7",
"created": "Tue, 15 Jun 2010 01:47:15 GMT"
},
{
"version": "v8",
"created": "Wed, 16 Jun 2010 06:34:44 GMT"
},
{
"version": "v9",
"created": "Fri, 18 Jun 2010 12:20:45 GMT"
}
] | 2023-05-31T00:00:00 | [
[
"Shinya",
"Hisanobu",
""
]
] |
0706.0358 | Russell Lyons | Russell Lyons and Benjamin J. Morris and Oded Schramm | Ends in Uniform Spanning Forests | 22 pages | Electron. J. Probab. 13 Paper 58 (2008), 1701-1725. | null | null | math.PR | null | It has hitherto been known that in a transitive unimodular graph, each tree
in the wired spanning forest has only one end a.s. We dispense with the
assumptions of transitivity and unimodularity, replacing them with a much
broader condition on the isoperimetric profile that requires just slightly more
than uniform transience.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 01:04:56 GMT"
},
{
"version": "v2",
"created": "Fri, 23 May 2008 21:50:12 GMT"
}
] | 2010-04-27T00:00:00 | [
[
"Lyons",
"Russell",
""
],
[
"Morris",
"Benjamin J.",
""
],
[
"Schramm",
"Oded",
""
]
] |
0706.0359 | Nicholas S. Witte | A.V. Kitaev, N.S. Witte | Boundary Conditions for Scaled Random Matrix Ensembles in the Bulk of
the Spectrum | 23 pages, 2 figures, to appear in proceedings of Symmetries and
Integrability of Difference Equations VII, Melbourne 2006 | null | 10.1088/1751-8113/40/42/S16 | null | math.CA math-ph math.MP | null | A spectral average which generalises the local spacing distribution of the
eigenvalues of random $ N\times N $ hermitian matrices in the bulk of their
spectrum as $ N\to\infty $ is known to be a $\tau$-function of the fifth
Painlev\'e system. This $\tau$-function, $ \tau(s) $, has generic parameters
and is transcendental but is characterised by particular boundary conditions
about the singular point $s=0$, which we determine here. When the average
reduces to the local spacing distribution we find that $\tau$-function is of
the separatrix, or partially truncated type.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 01:10:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kitaev",
"A. V.",
""
],
[
"Witte",
"N. S.",
""
]
] |
0706.0360 | Liam McAllister | Daniel Baumann, Anatoly Dymarsky, Igor R. Klebanov, Liam McAllister | Towards an Explicit Model of D-brane Inflation | 68 pages, 6 figures; v2: fixed typos, added refs and clarifications;
v3: expanded discussion of inflection point inflation | JCAP 0801:024,2008 | 10.1088/1475-7516/2008/01/024 | null | hep-th astro-ph | null | We present a detailed analysis of an explicit model of warped D-brane
inflation, incorporating the effects of moduli stabilization. We consider the
potential for D3-brane motion in a warped conifold background that includes
fluxes and holomorphically-embedded D7-branes involved in moduli stabilization.
Although the D7-branes significantly modify the inflaton potential, they do not
correct the quadratic term in the potential, and hence do not cause a uniform
change in the slow-roll parameter eta. Nevertheless, we present a simple
example based on the Kuperstein embedding of D7-branes, z_1=constant, in which
the potential can be fine-tuned to be sufficiently flat for inflation. To
derive this result, it is essential to incorporate the fact that the
compactification volume changes slightly as the D3-brane moves. We stress that
the compactification geometry dictates certain relationships among the
parameters in the inflaton Lagrangian, and these microscopic constraints impose
severe restrictions on the space of possible models. We note that the shape of
the final inflaton potential differs from projections given in earlier studies:
in configurations where inflation occurs, it does so near an inflection point.
Finally, we comment on the difficulty of making precise cosmological
predictions in this scenario. This is the companion paper to arXiv:0705.3837.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 19:57:46 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Aug 2007 01:04:48 GMT"
},
{
"version": "v3",
"created": "Sat, 15 Dec 2007 22:44:30 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"Baumann",
"Daniel",
""
],
[
"Dymarsky",
"Anatoly",
""
],
[
"Klebanov",
"Igor R.",
""
],
[
"McAllister",
"Liam",
""
]
] |
0706.0361 | Alexey Goldin | Alexey Goldin and Valery Makarov | Astrometric Orbits for Hipparcos Stochastic Binaries | This is followup to astro-ph/0606293 | null | 10.1086/520513 | null | astro-ph | null | Taking advantage of an improved genetic optimization algorithm for fitting
unconstrained Kepler orbits to the Hipparcos intermediate astrometric data, we
obtain additional orbital solutions for 81 Hipparcos stars with previous
stochastic (failed) solutions. The sample includes astrophysically interesting
objects, including the old disk wide binary HIP 754, the nearby AGB star HIP
34922 (L2 Pup), and the nearby M2 dwarf HIP 5496 (GJ 54, at 8 pc from the Sun)
which has a resolved M dwarf companion.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 01:19:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Goldin",
"Alexey",
""
],
[
"Makarov",
"Valery",
""
]
] |
0706.0362 | Aidan Sims | David Pask, John Quigg and Aidan Sims | Coverings of skew-products and crossed products by coactions | 19 pages, laTeX. v2: Minor modifications to version 1. This version
to appear in the Journal of the Australian Mathematical Society v3: some
potentially confusing typos corrected in the proof of Theorem~3.1, as well as
a few others. References updated | null | null | null | math.OA | null | Consider a projective limit G of finite groups G_n. Fix a compatible family
\delta^n of coactions of the G_n on a C*-algebra A. From this data we obtain a
coaction \delta of G on A. We show that the coaction crossed product of A by
\delta is isomorphic to a direct limit of the coaction crossed products of A by
the \delta^n.
If A = C*(\Lambda) for some k-graph \Lambda, and if the coactions \delta^n
correspond to skew-products of \Lambda, then we can say more. We prove that the
coaction crossed-product of C*(\Lambda) by \delta may be realised as a full
corner of the C*-algebra of a (k+1)-graph. We then explore connections with
Yeend's topological higher-rank graphs and their C*-algebras.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 06:09:18 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Mar 2008 23:21:05 GMT"
},
{
"version": "v3",
"created": "Wed, 14 May 2008 02:21:04 GMT"
}
] | 2008-05-14T00:00:00 | [
[
"Pask",
"David",
""
],
[
"Quigg",
"John",
""
],
[
"Sims",
"Aidan",
""
]
] |
0706.0363 | Sergey Kozitskiy Dr. | S. B. Kozitskiy | Amplitude equations for a system with thermohaline convection | 21 pages, 8 figures | Journal of Applied Mechanics and Technical Physics, V. 41, No. 3,
2000, P. 429-438 | 10.1007/BF02465292 | null | physics.flu-dyn physics.ao-ph | null | The multiple scale expansion method is used to derive amplitude equations for
a system with thermohaline convection in the neighborhood of Hopf and Taylor
bifurcation points and at the double zero point of the dispersion relation. A
complex Ginzburg-Landau equation, a Newell-Whitehead-type equation, and an
equation of the $\phi^4$ type, respectively, were obtained. Analytic
expressions for the coefficients of these equations and their various
asymptotic forms are presented. In the case of Hopf bifurcation for low and
high frequencies, the amplitude equation reduces to a perturbed nonlinear
Schr\"odinger equation. In the high-frequency limit, structures of the type of
"dark" solitons are characteristic of the examined physical system.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 01:21:16 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Kozitskiy",
"S. B.",
""
]
] |
0706.0364 | Myungseok Yoon | Myungseok Yoon, Jihye Ha, and Wontae Kim | Entropy of Reissner-Nordstrom Black Holes with Minimal Length Revisited | 5 pages | Phys.Rev.D76:047501,2007 | 10.1103/PhysRevD.76.047501 | null | gr-qc | null | Based on the generalized uncertainty principle, we study the entropy of a
four-dimensional black hole by counting degrees of freedom near the horizon and
obtain the (finite) entropy proportional to the surface area at the horizon
without a cutoff introduced in the conventional brick-wall method.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:11:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yoon",
"Myungseok",
""
],
[
"Ha",
"Jihye",
""
],
[
"Kim",
"Wontae",
""
]
] |
0706.0365 | William McElgin | Will McElgin | Notes on Liouville Theory at c<=1 | 31 pages, 4 figures | Phys.Rev.D77:066009,2008 | 10.1103/PhysRevD.77.066009 | EFI-07-14 | hep-th | null | The continuation of the Liouville conformal field theory to c<=1 is
considered. The viability of an interpretation involving a timelike boson which
is the conformal factor for two-dimensional asymptotically de Sitter geometries
is examined. The conformal bootstrap leads to a three-point function with a
unique analytic factor which is the same as that which appears along with the
fusion coefficients in the minimal models. A corresponding non-analytic factor
produces a well-defined metric on fields only when the central charge is
restricted to those of the topological minimal models, and when the conformal
dimensions satisfy h>(c-1)/24. However, the theories considered here have a
continuous spectrum which excludes the degenerate representations appearing in
the minimal models. The c=1 theory has been investigated previously using
similar techniques, and is identical to a non-rational CFT which arises as a
limit of unitary minimal models. When coupled to unitary matter fields, the
non-unitary theories with c<=-2 produce string amplitudes which are similar to
those of the minimal string.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:14:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"McElgin",
"Will",
""
]
] |
0706.0366 | Heidi Fearn Prof | Curtis Horn and Heidi Fearn | On the flight of an American Football | 22 pages and 7 figures | null | null | null | physics.pop-ph physics.gen-ph | null | In this paper we examine the detailed theory of the American football in
flight, with spin and air resistance included. We find the theory has much in
common with the theory of a gyroscope and also rocket trajectory with a
misaligned thruster. Unfortunately most of the air resistance data, for
rocketry and ballistics, is for speeds of Mach 1 or higher, where the air
resistance increases dramatically. We shall approximate a realistic air
resistance, at the slower speeds of football flight, with a drag force
proportional to cross sectional area and either $v$ or $v^2$, depending on
speed, where $v$ is velocity of the football. We begin with a discussion of the
motion, giving as much detail as possible without the use of complex analytic
calculations. We point out the previous errors made with moments of inertia and
make the necessary corrections for more accurate results. We show that the
shape of an American football closely resembles a parabola of revolution.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 18:34:09 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Horn",
"Curtis",
""
],
[
"Fearn",
"Heidi",
""
]
] |
0706.0367 | Ryoji Enomoto | S.Kabuki, R.Enomoto, CANGAROO-III collaboration | CANGAROO-III Search for Gamma Rays from Centaurus A and the $\omega$
Centauri Region | 7 pages, 6 figures, to appear in ApJ, emulateapj.cls | ApJ, 668 (2007) 968-973 | 10.1086/520767 | null | astro-ph | null | We have observed the giant radio galaxy Centaurus A and the globular cluster
$\omega$ Centauri in the TeV energy region using the CANGAROO-III stereoscopic
system. The system has been in operation since 2004 withan array of four
Imaging Atmospheric Cherenkov Telescopes (IACT) with $\sim$100-m spacings. The
observations were carried out in March and April 2004. In total, approximately
10 hours data were obtained for each target.No statistically significant
gamma-ray signal has been found above 420 GeV over a wide angular region (a
one-degree radius from thepointing center) and we derive flux upper limits
using all of the field of view.Implications for the total energy of cosmic rays
and the density of the cold dark matter are considered.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:28:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kabuki",
"S.",
""
],
[
"Enomoto",
"R.",
""
],
[
"collaboration",
"CANGAROO-III",
""
]
] |
0706.0368 | Laurence G. Yaffe | Laurence G. Yaffe and Paul M. Chesler | The wake of a quark moving through a strongly-coupled $\mathcal N=4$
supersymmetric Yang-Mills plasma | 4 pages, typos fixed | Phys.Rev.Lett.99:152001,2007 | 10.1103/PhysRevLett.99.152001 | null | hep-th hep-ph | null | The energy density wake produced by a heavy quark moving through a strongly
coupled N=4 supersymmetric Yang-Mills plasma is computed using gauge/string
duality.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:46:30 GMT"
},
{
"version": "v2",
"created": "Wed, 15 Aug 2007 22:24:11 GMT"
},
{
"version": "v3",
"created": "Sat, 8 Dec 2007 21:59:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yaffe",
"Laurence G.",
""
],
[
"Chesler",
"Paul M.",
""
]
] |
0706.0369 | Naoki Yasuda | Naoki Yasuda, Masataka Fukugita and Donald P. Schneider | Spatial Variations of Galaxy Number Counts in the Sloan Digital Sky
Survey. II. Test of Galactic Extinction in High Extinction Regions | null | Astron.J.134:698-705,2007 | 10.1086/519836 | null | astro-ph | null | Galactic extinction is tested using galaxy number counts at low Galactic
latitude obtained from five band photometry of the Sloan Digital Sky Survey.
The spatial variation of galaxy number counts for low extinction regions of
$E(B-V) < 0.15$ is consistent with the all-sky reddening map of Schlegel,
Finkbeiner, & Davis (1998) and the standard extinction law. For higher
extinction regions of $E(B-V) > 0.15$, however, the map of Schlegel et
al.(1998) overestimates the reddening by a factor up to 1.4, which is likely
ascribed to the departure from proportionality of reddening to infrared
emissivity of dust. This result is consistent with the analysis of Arce &
Goodman (1999) for the Taurus dark cloud complex.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:40:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Yasuda",
"Naoki",
""
],
[
"Fukugita",
"Masataka",
""
],
[
"Schneider",
"Donald P.",
""
]
] |
0706.0370 | Prof. Dr. M. W. Wu | J. L. Cheng, M. W. Wu | Kinetic investigation on extrinsic spin Hall effect induced by skew
scattering | 5 pages, 2 figures, to be published in JPCM | J. Phys.: Condens. Matter 20, 085209 (2008). | 10.1088/0953-8984/20/8/085209 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | The kinetics of the extrinsic spin Hall conductivity induced by the skew
scattering is performed from the fully microscopic kinetic spin Bloch equation
approach in $(001)$ GaAs symmetric quantum well. In the steady state, the
extrinsic spin Hall current/conductivity vanishes for the linear-$\mathbf k$
dependent spin-orbit coupling and is very small for the cubic-$\mathbf k$
dependent spin-orbit coupling. The spin precession induced by the
Dresselhaus/Rashba spin-orbit coupling plays a very important role in the
vanishment of the extrinsic spin Hall conductivity in the steady state. An
in-plane spin polarization is induced by the skew scattering, with the help of
the spin-orbit coupling. This spin polarization is very different from the
current-induced spin polarization.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 02:43:30 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Jan 2008 11:57:17 GMT"
}
] | 2008-02-02T00:00:00 | [
[
"Cheng",
"J. L.",
""
],
[
"Wu",
"M. W.",
""
]
] |
0706.0371 | Li Sheng | L. Sheng, D. N. Sheng, F. D. M. Haldane, and Leon Balents | Odd-Integer Quantum Hall Effect in Graphene: Interaction and Disorder
Effects | 5 pages, 5 figures | Phys. Rev. Lett. 99, 196802 (2007) | 10.1103/PhysRevLett.99.196802 | null | cond-mat.mes-hall | null | We study the competition between the long-range Coulomb interaction, disorder
scattering, and lattice effects in the integer quantum Hall effect (IQHE) in
graphene. By direct transport calculations, both $\nu=1$ and $\nu=3$ IQHE
states are revealed in the lowest two Dirac Landau levels. However, the
critical disorder strength above which the $\nu=3$ IQHE is destroyed is much
smaller than that for the $\nu=1$ IQHE, which may explain the absence of a
$\nu=3$ plateau in recent experiments. While the excitation spectrum in the
IQHE phase is gapless within numerical finite-size analysis, we do find and
determine a mobility gap, which characterizes the energy scale of the stability
of the IQHE. Furthermore, we demonstrate that the $\nu=1$ IQHE state is a Dirac
valley and sublattice polarized Ising pseudospin ferromagnet, while the $\nu=3$
state is an $xy$ plane polarized pseudospin ferromagnet.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 03:35:18 GMT"
},
{
"version": "v2",
"created": "Sun, 16 Sep 2007 04:21:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sheng",
"L.",
""
],
[
"Sheng",
"D. N.",
""
],
[
"Haldane",
"F. D. M.",
""
],
[
"Balents",
"Leon",
""
]
] |
0706.0372 | Jerzy Kocik | Jerzy Kocik | A theorem on circle configurations | 16 pages, 13 figures | null | null | null | math.HO | null | A formula for the radii and positions of four circles in the plane for an
arbitrary linearly independent circle configuration is found. Among special
cases is the recent extended Descartes Theorem on the Descartes configuration
and an analytic solution to the Apollonian problem. The general theorem for
n-spheres is also considered.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:04:12 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Jun 2007 23:23:34 GMT"
}
] | 2007-06-07T00:00:00 | [
[
"Kocik",
"Jerzy",
""
]
] |
0706.0373 | Kohei Hamaya | K. Hamaya, M. Kitabatake, K. Shibata, M. Jung, M. Kawamura, K.
Hirakawa, T. Machida, S. Ishida, and Y. Arakawa | Electric-field control of tunneling magnetoresistance effect in a
Ni/InAs/Ni quantum-dot spin valve | 3 pages, 3 figures | Appl. Phys. Lett. 91, 022107 (2007) | 10.1063/1.2759264 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | We demonstrate an electric-field control of tunneling magnetoresistance (TMR)
effect in a semiconductor quantum-dot (QD) spin-valve device. By using
ferromagnetic Ni nano-gap electrodes, we observe the Coulomb blockade
oscillations at a small bias voltage. In the vicinity of the Coulomb blockade
peak, the TMR effect is significantly modulated and even its sign is switched
by changing the gate voltage, where the sign of the TMR value changes at the
resonant condition.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:07:16 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 11:36:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hamaya",
"K.",
""
],
[
"Kitabatake",
"M.",
""
],
[
"Shibata",
"K.",
""
],
[
"Jung",
"M.",
""
],
[
"Kawamura",
"M.",
""
],
[
"Hirakawa",
"K.",
""
],
[
"Machida",
"T.",
""
],
[
"Ishida",
"S.",
""
],
[
"Arakawa",
"Y.",
""
]
] |
0706.0374 | Dongho Chae | Dongho Chae | On the apparition of singularities of vector fields transported by
volume preserving diffeomorphisms | 15 pages | null | null | null | math.AP | null | We consider possible generation of singularities of a vector field
transported by diffeomorphisms with derivatives of uniformly bounded
determinants. A particular case of volume preserving diffeomrphism is the most
important, since it has direct applications to the incompressible, inviscid
hydrodynamics. We find relations between the directions of the vector field and
the eigenvectors of the derivative of the back-to-label map near the
singularity. We also find an invariant when we follow the motion of the
integral curves of the vector field. For the 3D Euler equations these results
have immediate implications about the directions of the vortex stretching and
the material stretching near the possible singularities. We also have similar
applications to the other inviscid, incompressible fluid equations such as the
2D quasi-geostrophic equation and the 3D magnetohydrodynamics equations.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:12:25 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Chae",
"Dongho",
""
]
] |
0706.0375 | Sumati Surya | Graham Brightwell, Joe Henson, Sumati Surya | A 2D model of Causal Set Quantum Gravity: The emergence of the continuum | Corrections and clarifications. Conclusions unchanged | Class.Quant.Grav.25:105025,2008 | 10.1088/0264-9381/25/10/105025 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Non-perturbative theories of quantum gravity inevitably include
configurations that fail to resemble physically reasonable spacetimes at large
scales. Often, these configurations are entropically dominant and pose an
obstacle to obtaining the desired classical limit. We examine this "entropy
problem" in a model of causal set quantum gravity corresponding to a
discretisation of 2D spacetimes. Using results from the theory of partial
orders we show that, in the large volume or continuum limit, its partition
function is dominated by causal sets which approximate to a region of 2D
Minkowski space. This model of causal set quantum gravity thus overcomes the
entropy problem and predicts the emergence of a physically reasonable geometry.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:14:34 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Nov 2007 06:47:55 GMT"
},
{
"version": "v3",
"created": "Wed, 17 Sep 2008 09:33:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Brightwell",
"Graham",
""
],
[
"Henson",
"Joe",
""
],
[
"Surya",
"Sumati",
""
]
] |
0706.0376 | Subham Majumdar | M. Patra, K. De, S. Majumdar, S. Giri | Exchange bias with Fe substitution in LaMnO_3 | 6 figures | null | 10.1140/epjb/e2007-00253-9 | null | cond-mat.str-el cond-mat.mtrl-sci | null | The exchange bias (EB) in LaMn_{0.7}Fe_{0.3}O_3 is observed by the negative
shift and training effect of the hysteresis loops, while the sample was cooled
in external magnetic field. The analysis of cooling field dependence of EB
gives the size of the ferromagnetic (FM) cluster ~ 25 Angstrom, where the
magnetic anisotropy of FM cluster is found two order of magnitude higher than
the FM bulk manganites. We propose that the nanoscale FM clusters are embedded
in the glassy magnetic host with EB at the FM/glassy magnetic interface.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:15:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Patra",
"M.",
""
],
[
"De",
"K.",
""
],
[
"Majumdar",
"S.",
""
],
[
"Giri",
"S.",
""
]
] |
0706.0377 | Kazim Buyukboduk | Kazim Buyukboduk | $\Lambda$-adic Kolyvagin systems | (almost) final version, to appear in IMRN | null | 10.1093/imrn/rnq186 | null | math.NT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we study the deformations of Kolyvagin systems that are known
to exist in a wide variety of cases, by the work of B. Howard, B. Mazur, and K.
Rubin for the residual Galois representations, along the cyclotomic Iwasawa
algebra. We prove, under certain technical hypotheses, that a cyclotomic
deformation of a Kolyvagin system exists. We also briefly discuss how our
techniques could be extended to prove that one could deform Kolyvagin systems
for other deformations as well.
We discuss several applications of this result, particularly relation of
these $\Lambda$-adic Kolyvagin systems to p-adic L-functions (in view of the
conjectures of Perrin-Riou on p-adic L-functions) and applications to main
conjectures; also applications to the study of Iwasawa theory of Rubin-Stark
units.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:18:11 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Mar 2011 09:59:40 GMT"
}
] | 2013-03-08T00:00:00 | [
[
"Buyukboduk",
"Kazim",
""
]
] |
0706.0378 | Gergely G\'abor Barnaf\"oldi | G.G. Barnafoldi, P. Levai, B. Lukacs | Searching Extra Dimensions in Compact Stars | 4 pages, 3 figures, submitted to Astron. Nachrichten | Astron. Nachrichten 328, 809-812 (2007) | 10.1002/asna.200710806 | null | astro-ph | null | The electro-magnetic and particle radiation detected from the direction of
Cygnus X3 raise the question of the existence of special long-lived, neutral
particles. We investigate the origin of these particles in a special approach:
the source object may contain compactified extra dimension and these particles
are messengers of this state. We describe hyperon stars in 3+1 dimension and
introduce the description of a compact stars in 3+1_c+1 dimensional space-time.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 05:40:10 GMT"
}
] | 2008-07-31T00:00:00 | [
[
"Barnafoldi",
"G. G.",
""
],
[
"Levai",
"P.",
""
],
[
"Lukacs",
"B.",
""
]
] |
0706.0379 | Kensuke Kobayashi | Michael P. Delmo, Kensuke Kobayashi, Shinpei Yamamoto, Yoshinori
Tamada, Mikio Takano, Shinya Kasai, and Teruo Ono | Giant Magnetoresistive Effect in Colloidal Magnetic Nanoparticles | null | null | null | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | This paper has been withdrawn by the authors.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:11:49 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 04:26:31 GMT"
},
{
"version": "v3",
"created": "Tue, 10 Jul 2007 03:53:33 GMT"
}
] | 2007-07-10T00:00:00 | [
[
"Delmo",
"Michael P.",
""
],
[
"Kobayashi",
"Kensuke",
""
],
[
"Yamamoto",
"Shinpei",
""
],
[
"Tamada",
"Yoshinori",
""
],
[
"Takano",
"Mikio",
""
],
[
"Kasai",
"Shinya",
""
],
[
"Ono",
"Teruo",
""
]
] |
0706.0380 | Julius Vanko | Viliam Pazma and Julius Vanko | Simple Model of Particle Detector and Arrival Time | 6 pages | null | null | null | quant-ph | null | We present the very simple model of a particle detector and the proposal for
the calculation of the average value of the time of arrival.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 06:21:57 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Pazma",
"Viliam",
""
],
[
"Vanko",
"Julius",
""
]
] |
0706.0381 | Christof Aegerter | S. Fiebig, C.M. Aegerter, W. B\"uhrer, M. St\"orzer, E. Akkermans, G.
Montambaux, and G. Maret | Conservation of energy in coherent backscattering of light | 4 pages | null | 10.1209/0295-5075/81/64004 | null | cond-mat.dis-nn | null | Although conservation of energy is fundamental in physics, its principles
seem to be violated in the field of wave propagation in turbid media by the
energy enhancement of the coherent backscattering cone. In this letter we
present experimental data which show that the energy enhancement of the cone is
balanced by an energy cutback at all scattering angles. Moreover, we give a
complete theoretical description, which is in good agreement with these data.
The additional terms needed to enforce energy conservation in this description
result from an interference effect between incident and multiply scattered
waves, which is reminiscent of the optical theorem in single scattering.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 06:37:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fiebig",
"S.",
""
],
[
"Aegerter",
"C. M.",
""
],
[
"Bührer",
"W.",
""
],
[
"Störzer",
"M.",
""
],
[
"Akkermans",
"E.",
""
],
[
"Montambaux",
"G.",
""
],
[
"Maret",
"G.",
""
]
] |
0706.0382 | David P. Rideout | Johannes Brunnemann and David Rideout | Properties of the Volume Operator in Loop Quantum Gravity II: Detailed
Presentation | Companion to arXiv:0706.0469. Version as published in CQG in 2008.
More compact presentation. Sign factor combinatorics now much better
understood in context of oriented matroids, see arXiv:1003.2348, where also
important remarks given regarding sigma configurations. Subsequent
computations revealed some minor errors, which do not change qualitative
results but modify some numbers presented here | Class.Quant.Grav.25:065002,2008 | 10.1088/0264-9381/25/6/065002 | Imperial/TP/2007/DR/02 | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The properties of the Volume operator in Loop Quantum Gravity, as constructed
by Ashtekar and Lewandowski, are analyzed for the first time at generic
vertices of valence greater than four. The present analysis benefits from the
general simplified formula for matrix elements of the Volume operator derived
in gr-qc/0405060, making it feasible to implement it on a computer as a matrix
which is then diagonalized numerically. The resulting eigenvalues serve as a
database to investigate the spectral properties of the volume operator.
Analytical results on the spectrum at 4-valent vertices are included. This is a
companion paper to arXiv:0706.0469, providing details of the analysis presented
there.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 18:39:11 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Nov 2010 17:43:31 GMT"
}
] | 2010-11-26T00:00:00 | [
[
"Brunnemann",
"Johannes",
""
],
[
"Rideout",
"David",
""
]
] |
0706.0383 | Takaya Nozawa | Takaya Nozawa, Takashi Kozasa, Asao Habe, Eli Dwek, Hideyuki Umeda,
Nozomu Tominaga, Keiichi Maeda, and Ken'ichi Nomoto | Evolution of Dust in Primordial Supernova Remnants: Can Dust Grains
Formed in the Ejecta Survive and be Injected into the Early Interstellar
Medium? | 35 pages including 10 figures and 5 tables. Accepted for publication
in ApJ | Astrophys.J.666:955-966,2007 | 10.1086/520621 | null | astro-ph | null | We investigate the evolution of dust that formed at Population III supernova
(SN) explosions and its processing through the collisions with the reverse
shocks resulting from the interaction of the SN ejecta with the ambient medium.
In particular, we investigate the transport of the shocked dust within the SN
remnant (SNR), and its effect on the chemical composition, the size
distribution, and the total mass of dust surviving in SNR. We find that the
evolution of the reverse shock, and hence its effect on the processing of the
dust depends on the thickness of the envelope retained by the progenitor star.
Furthermore, the transport and survival of the dust grains depend on their
initial radius, a_{ini}, and composition: For Type II SNRs expanding into the
interstellar medium (ISM) with a density of n_{H,0}=1 cm^{-3}, small grains
with a_{ini} < ~ 0.05 micron are completely destroyed by sputtering in the
postshock flow, while grains with a_{ini}= 0.05--0.2 micron are trapped into
the dense shell behind the forward shock. Very large grains of a_{ini} > ~ 0.2
micron are ejected into the ISM without decreasing their sizes significantly.
We find that the total mass fraction of dust that is destroyed by the reverse
shock ranges from 0.2 to 1.0, depending on the energy of the explosion and the
density of the ambient ISM. The results of our calculations have significant
impact on the abundance pattern of subsequent generation of stars that form in
the dense shell of primordial SNRs.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 07:20:47 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Nozawa",
"Takaya",
""
],
[
"Kozasa",
"Takashi",
""
],
[
"Habe",
"Asao",
""
],
[
"Dwek",
"Eli",
""
],
[
"Umeda",
"Hideyuki",
""
],
[
"Tominaga",
"Nozomu",
""
],
[
"Maeda",
"Keiichi",
""
],
[
"Nomoto",
"Ken'ichi",
""
]
] |
0706.0384 | Qiang Zhao | Gang Li, Qiang Zhao and Bing-Song Zou | Isospin violation in $\phi, J/\psi, \psi^\prime \to \omega \pi^0$ via
hadronic loops | Revised version resubmitted to PRD; Additional loop contributions
included; Conclusion unchanged | Phys.Rev.D77:014010,2008 | 10.1103/PhysRevD.77.014010 | null | hep-ph | null | In this work, we study the isospin-violating decay of $\phi\to \omega\pi^0$
and quantify the electromagnetic (EM) transitions and intermediate meson
exchanges as two major sources of the decay mechanisms. In the EM decays, the
present datum status allows a good constraint on the EM decay form factor in
the vector meson dominance (VMD) model, and it turns out that the EM transition
can only account for about $1/4\sim 1/3$ of the branching ratio for $\phi\to
\omega\pi^0$. The intermediate meson exchanges, $K\bar{K}(K^*)$ (intermediate
$K\bar{K}$ interaction via $K^*$ exchanges), $K\bar{K^*}(K)$ (intermediate
$K\bar{K^*}$ rescattering via kaon exchanges), and $K\bar{K^*}(K^*)$
(intermediate $K\bar{K^*}$ rescattering via $K^*$ exchanges), which evade the
naive Okubo-Zweig-Iizuka (OZI) rule, serve as another important contribution to
the isospin violations. They are evaluated with effective Lagrangians where
explicit constraints from experiment can be applied. Combining these three
contributions, we obtain results in good agreement with the experimental data.
This approach is also extended to $J/\psi(\psi^\prime)\to \omega\pi^0$, where
we find contributions from the $K\bar{K}(K^*)$, $K\bar{K^*}(K)$ and
$K\bar{K^*}(K^*)$ loops are negligibly small, and the isospin violation is
likely to be dominated by the EM transition.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 07:03:55 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Jun 2007 01:41:13 GMT"
},
{
"version": "v3",
"created": "Fri, 26 Oct 2007 13:30:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Li",
"Gang",
""
],
[
"Zhao",
"Qiang",
""
],
[
"Zou",
"Bing-Song",
""
]
] |
0706.0385 | Ilya Usoskin | I.G. Usoskin, S.K. Solanki, G.A. Kovaltsov | Grand minima and maxima of solar activity: New observational constraints | 10 Figures | Astron.Astrophys.471:301-309,2007 | 10.1051/0004-6361:20077704 | null | astro-ph | null | Using a reconstruction of sunspot numbers stretching over multiple millennia,
we analyze the statistics of the occurrence of grand minima and maxima and set
new observational constraints on long-term solar and stellar dynamo models.
We present an updated reconstruction of sunspot number over multiple
millennia, from $^{14}$C data by means of a physics-based model, using an
updated model of the evolution of the solar open magnetic flux. A list of grand
minima and maxima of solar activity is presented for the Holocene (since 9500
BC) and the statistics of both the length of individual events as well as the
waiting time between them are analyzed.
The occurrence of grand minima/maxima is driven not by long-term cyclic
variability, but by a stochastic/chaotic process. The waiting time distribution
of the occurrence of grand minima/maxima deviates from an exponential
distribution, implying that these events tend to cluster together with long
event-free periods between the clusters. Two different types of grand minima
are observed: short (30--90 years) minima of Maunder type and long ($>$110
years) minima of Sp\"orer type, implying that a deterministic behaviour of the
dynamo during a grand minimum defines its length. The duration of grand maxima
follows an exponential distribution, suggesting that the duration of a grand
maximum is determined by a random process.
These results set new observational constraints upon the long-term behaviour
of the solar dynamo.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 07:40:16 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Usoskin",
"I. G.",
""
],
[
"Solanki",
"S. K.",
""
],
[
"Kovaltsov",
"G. A.",
""
]
] |
0706.0386 | Anna Fino | Luis C. de Andr\'es, Marisa Fern\'andez, Anna Fino and Luis Ugarte | Contact 5-manifolds with SU(2)-structure | 23 pages, to be published in Q. J. Math | null | null | null | math.DG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider 5-manifolds with a contact form arising from a hypo structure,
which we call \emph{hypo-contact}. We provide conditions which imply that there
exists such a structure on an oriented hypersurface of a 6-manifold with a
half-flat SU(3)-structure. For half-flat manifolds with a Killing vector field
$X$ preserving the SU(3)-structure we study the geometry of the orbits space.
Moreover, we describe the solvable Lie algebras admitting a \emph{hypo-contact}
structure. This allows us exhibit examples of Sasakian $\eta$-Einstein
manifolds, as well as to prove that such structures give rise to new metrics
with holonomy SU(3) and to new metrics with holonomy $G_2$.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 07:50:27 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jun 2008 12:20:46 GMT"
}
] | 2008-06-20T00:00:00 | [
[
"de Andrés",
"Luis C.",
""
],
[
"Fernández",
"Marisa",
""
],
[
"Fino",
"Anna",
""
],
[
"Ugarte",
"Luis",
""
]
] |
0706.0387 | Daniel Burgarth | Daniel Burgarth | Quantum state transfer and time-dependent disorder in Quantum Chains | 9 pages, 6 figures, submitted to the proceedings of the 382. WEH
workshop "transrel" March 2007; added reference to experimental realization | Eur. Phys. J. Special Topics 151, 147-155 (2007) | 10.1140/epjst/e2007-00370-9 | null | quant-ph | null | One of the most basic tasks required for Quantum Information Technology is
the ability to connect different components of a Quantum Computer by quantum
wires that obey the superposition principle. Since superpositions can be very
sensitive to noise this turns out to be already quite difficult. Recently, it
was suggested to use chains of permanently coupled spin-1/2 particles (quantum
chains) for this purpose. They have the advantage that no external control
along the wire is required during the transport of information, which makes it
possible to isolate the wire from sources of noise. We first give an
introduction to basic quantum state transfer and review existing advanced
schemes by other authors. We then show a new result that demonstrates the
stability of the scheme [1] against disorder that is approximately constant
during one application of the channel, but time-dependent with respect to
multiple applications.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:06:29 GMT"
},
{
"version": "v2",
"created": "Thu, 14 Jun 2007 08:36:01 GMT"
},
{
"version": "v3",
"created": "Tue, 3 Jul 2007 13:49:25 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Burgarth",
"Daniel",
""
]
] |
0706.0388 | Oliver Lieleg | Oliver Lieleg and Andreas R. Bausch | Cross-linker unbinding and self-similarity in bundled cytoskeletal
networks | 5 pages, 4 figures (including supplementary information) | null | 10.1103/PhysRevLett.99.158105 | null | cond-mat.soft cond-mat.mtrl-sci | null | The macromechanical properties of purely bundled in vitro actin networks are
not only determined by the micromechanical properties of individual bundles but
also by molecular unbinding events of the actin binding protein (ABP) fascin.
Under high mechanical load the network elasticity depends on the forced
unbinding of individual ABPs in a rate dependent manner. Cross-linker unbinding
in combination with the structural self-similarity of the network enables the
introduction of a concentration/time superposition principle - broadening the
mechanically accessible frequency range over 8 orders of magnitude.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:11:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lieleg",
"Oliver",
""
],
[
"Bausch",
"Andreas R.",
""
]
] |
0706.0389 | Andriy Haydys | Andriy Haydys | Nonlinear Dirac operator and quaternionic analysis | Cosmetic changes only | Commun. Math. Phys. 281, 251-261 (2008) | 10.1007/s00220-008-0445-1 | null | math.DG math-ph math.MP | null | Properties of the Cauchy-Riemann-Fueter equation for maps between
quaternionic manifolds are studied. Spaces of solutions in case of maps from a
K3-surface to the cotangent bundle of a complex projective space are computed.
A relationship between harmonic spinors of a generalized nonlinear Dirac
operator and solutions of the Cauchy-Riemann-Fueter equation are established.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:23:42 GMT"
},
{
"version": "v2",
"created": "Fri, 30 May 2008 14:00:26 GMT"
}
] | 2008-05-30T00:00:00 | [
[
"Haydys",
"Andriy",
""
]
] |
0706.0390 | Jacques Moret-Bailly | Jacques Moret-Bailly | Superradiance and stimulated scattering in SNR 1987A | 6 pages, 3figures | null | null | null | physics.gen-ph | null | The rings observed around supernova remnant 1987A are emitted by a plasma
mainly made of ionized and neutral hydrogen atoms. With a density of 10 power
10 atoms per cubic metre, and at least a dimension of plasma of 0.01
light-year, the column density is 10 power 24 atoms per square metre, much more
than needed for an optically thick gas at Lyman frequencies (Case B). While, at
10000 K, the bulky gas would absorb Lyman lines fully, at 50000K it emits
superradiant lines. As superradiance de-excites the atoms strongly, nearly all
available energy is emitted in a few competing modes: Superradiance appears
only for beams which cross the largest column densities; for an observation
from Earth, these beams generate three elliptical hollow cylinders whose bases
are the observed rings; admitting that the Earth is not in a privileged
direction, these cylinders envelope ellipsoidal shells observed, for the
external rings, by photon echoes. For the equatorial ring, the brightness of
the superradiant beams is multiplied by a quasi-resonant induced scattering of
the rays emitted by the star. The de-excitation of atoms by emitted beams cools
the gas strongly, so that ionization decreases fast, the process self
accelerates. The energy of the high radiance rays from the star is strongly
scattered to the ring while the low radiance of the glow which surrounds the
star is rather amplified. The fast absorption of the radial beams produces the
radial decrease of radiance of the ring while a competition of modes produces
the pearls.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:19:05 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Moret-Bailly",
"Jacques",
""
]
] |
0706.0391 | Kwan Chuen Chan | K. C. Chan and M.-C. Chu | CMB Constraint on Radion Evolution in the Brane World Scenario | 7 pages, 6 figures, minor changes of format to conform with PRD
format | Phys.Rev.D76:043525,2007 | 10.1103/PhysRevD.76.043525 | null | astro-ph | null | In many versions of brane model, the modulus field of extra dimensions, the
radion, could have cosmological evolution, which induces variation of the Higgs
vacuum expectation value, $<H>$, resulting in cosmological variation of the
electron mass $m_e$. The formation of Cosmic Microwave Background (CMB)
anisotropies is thus affected, causing changes both in the peaks positions and
amplitudes in the CMB power spectra. Using the three-year Wilkinson Microwave
Anisotropies Probe (WMAP) CMB data, with the Hubble parameter $H_0$ fixed to be
the Hubble Space Telescope (HST) result 72 km s$^{-1}$ Mpc$^{-1}$, we obtain a
constraint on $\rho$, the ratio of the value of $<H>$ at CMB recombination to
its present value, to be [0.97, 1.02].
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:26:56 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 22:09:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chan",
"K. C.",
""
],
[
"Chu",
"M. -C.",
""
]
] |
0706.0392 | Zaza Osmanov | Z. Osmanov | Centrifugally driven electrostatic instability in extragalactic jets | 7 pages, 4 figures | null | 10.1063/1.2842365 | null | astro-ph | null | The stability problem of the rotation induced electrostatic wave in
extragalactic jets is presented. Solving a set of equations describing dynamics
of a relativistic plasma flow of AGN jets, an expression of the instability
rate has been derived and analyzed for typical values of AGNs. The growth rate
was studied versus the wave length and the inclination angle and it has been
found that the instability process is much efficient with respect to the
accretion disk evolution, indicating high efficiency of the instability.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:27:00 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 09:29:31 GMT"
},
{
"version": "v3",
"created": "Wed, 25 Jul 2007 13:31:00 GMT"
},
{
"version": "v4",
"created": "Mon, 17 Sep 2007 08:50:51 GMT"
},
{
"version": "v5",
"created": "Tue, 29 Jan 2008 09:58:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Osmanov",
"Z.",
""
]
] |
0706.0393 | Oliver Lieleg | Yuxia Luan, Oliver Lieleg, Bernd Wagner and Andreas R. Bausch | Micro- and Macrorheological Properties of Isotropically Cross-linked
Actin Networks | 14 pages, 5 figures | null | 10.1529/biophysj.107.112417 | null | cond-mat.soft | null | Cells make use of semi-flexible biopolymers such as actin or intermediate
filaments to control their local viscoelastic response by dynamically adjusting
the concentration and type of cross-linker molecules. The microstructure of the
resulting networks mainly determines their mechanical properties. It remains an
important challenge to relate structural transitions to both the molecular
properties of the cross-linking molecules and the mechanical response of the
network. This can be achieved best by well-defined in vitro model systems in
combination with microscopic techniques. Here, we show that with increasing
concentrations of the cross-linker HMM (heavy meromyosin) a transition in the
mechanical network response occurs. At low cross-linker densities the network
elasticity is dominated by the entanglement length of the polymer, while at
high HMM densities the cross-linker distance determines the elastic behavior.
Using microrheology the formation of heterogeneous networks is observed at low
cross-linker concentrations. Micro- and macrorheology both report the same
transition to a homogeneous cross-linked phase. This transition is set by a
constant average cross-linker distance. Thus, the micro- and macromechanical
properties of isotropically cross-linked in vitro actin networks are determined
by only one intrinsic network parameter.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:31:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Luan",
"Yuxia",
""
],
[
"Lieleg",
"Oliver",
""
],
[
"Wagner",
"Bernd",
""
],
[
"Bausch",
"Andreas R.",
""
]
] |
0706.0394 | Kavan Modi | Aik-meng Kuah and Kavan Modi and C\'esar A. Rodr\'iguez-Rosario and
E.C.G. Sudarshan | How state preparation can affect a quantum experiment: Quantum process
tomography for open systems | 13 pages, no figures, submitted to Phys. Rev. A | Phys. Rev. A 76, 042113 (2007) | 10.1103/PhysRevA.76.042113 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the effects of preparation of input states in a quantum tomography
experiment. We show that maps arising from a quantum process tomography
experiment (called process maps) differ from the well know dynamical maps. The
difference between the two is due to the preparation procedure that is
necessary for any quantum experiment. We study two preparation procedures,
stochastic preparation and preparation by measurements. The stochastic
preparation procedure yields process maps that are linear, while the
preparations using von Neumann measurements lead to non-linear processes, and
can only be consistently described by a bi-linear process map. A new process
tomography recipe is derived for preparation by measurement for qubits. The
difference between the two methods is analyzed in terms of a quantum process
tomography experiment. A verification protocol is proposed to differentiate
between linear processes and bi-linear processes. We also emphasize the
preparation procedure will have a non-trivial effect for any quantum experiment
in which the system of interest interacts with its environment.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:51:25 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 01:19:11 GMT"
},
{
"version": "v3",
"created": "Thu, 29 Oct 2009 09:08:43 GMT"
}
] | 2009-10-29T00:00:00 | [
[
"Kuah",
"Aik-meng",
""
],
[
"Modi",
"Kavan",
""
],
[
"Rodríguez-Rosario",
"César A.",
""
],
[
"Sudarshan",
"E. C. G.",
""
]
] |
0706.0395 | Dario Gerace | L. C. Andreani and D. Gerace | Photonic-crystal slabs with a triangular lattice of triangular holes
investigated using a guided-mode expansion method | 16 pages, 11 figures | Phys. Rev. B vol. 73 p. 235114 (2006) | 10.1103/PhysRevB.73.235114 | null | cond-mat.soft cond-mat.mtrl-sci physics.optics | null | According to a recent proposal [S. Takayama et al., Appl. Phys. Lett. 87,
061107 (2005)], the triangular lattice of triangular air holes may allow to
achieve a complete photonic band gap in two-dimensional photonic crystal slabs.
In this work we present a systematic theoretical study of this photonic lattice
in a high-index membrane, and a comparison with the conventional triangular
lattice of circular holes, by means of the guided-mode expansion method whose
detailed formulation is described here. Photonic mode dispersion below and
above the light line, gap maps, and intrinsic diffraction losses of
quasi-guided modes are calculated for the periodic lattice as well as for line-
and point-defects defined therein. The main results are summarized as follows:
(i) the triangular lattice of triangular holes does indeed have a complete
photonic band gap for the fundamental guided mode, but the useful region is
generally limited by the presence of second-order waveguide modes; (ii) the
lattice may support the usual photonic band gap for even modes (quasi-TE
polarization) and several band gaps for odd modes (quasi-TM polarization),
which could be tuned in order to achieve doubly-resonant frequency conversion
between an even mode at the fundamental frequency and an odd mode at the
second-harmonic frequency; (iii) diffraction losses of quasi-guided modes in
the triangular lattices with circular and triangular holes, and in line-defect
waveguides or point-defect cavities based on these geometries, are comparable.
The results point to the interest of the triangular lattice of triangular holes
for nonlinear optics, and show the usefulness of the guided-mode expansion
method for calculating photonic band dispersion and diffraction losses,
especially for higher-lying photonic modes.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 08:56:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Andreani",
"L. C.",
""
],
[
"Gerace",
"D.",
""
]
] |
0706.0396 | Dario Gerace | D. Gerace, L. C. Andreani | Quantum theory of exciton-photon coupling in photonic crystal slabs with
embedded quantum wells | 14 pages, 9 figures, to appear in Phys. Rev. B | Phys. Rev. B vol. 75 p. 235325 (2007) | 10.1103/PhysRevB.75.235325 | null | cond-mat.soft physics.optics | null | A theoretical description of radiation-matter coupling for
semiconductor-based photonic crystal slabs is presented, in which quantum wells
are embedded within the waveguide core layer. A full quantum theory is
developed, by quantizing both the electromagnetic field with a spatial
modulation of the refractive index and the exciton center of mass field in a
periodic piecewise constant potential. The second-quantized hamiltonian of the
interacting system is diagonalized with a generalized Hopfield method, thus
yielding the complex dispersion of mixed exciton-photon modes including losses.
The occurrence of both weak and strong coupling regimes is studied, and it is
concluded that the new eigenstates of the system are described by
quasi-particles called photonic crystal polaritons, which can occur in two
situations: (i) below the light line, when a resonance between exciton and
non-radiative photon levels occurs (guided polaritons), (ii) above the light
line, provided the exciton-photon coupling is larger than the intrinsic
radiative damping of the resonant photonic mode (radiative polaritons). For a
square lattice of air holes, it is found that the energy minimum of the lower
polariton branch can occur around normal incidence. The latter result has
potential implications for the realization of polariton parametric interactions
in photonic crystal slabs.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:04:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gerace",
"D.",
""
],
[
"Andreani",
"L. C.",
""
]
] |
0706.0397 | Hiroki Takesue | Hiroki Takesue, Sae Woo Nam, Qiang Zhang, Robert H. Hadfield,
Toshimori Honjo, Kiyoshi Tamaki, and Yoshihisa Yamamoto | Quantum key distribution over 40 dB channel loss using superconducting
single photon detectors | 15 pages, 5 figures. Original version | Nature Photonics 1, 343 (2007) (revised version) | 10.1038/nphoton.2007.75 | null | quant-ph | null | Quantum key distribution (QKD) offers an unconditionally secure means of
communication based on the laws of quantum mechanics. Currently, a major
challenge is to achieve a QKD system with a 40 dB channel loss, which is
required if we are to realize global scale QKD networks using communication
satellites. Here we report the first QKD experiment in which secure keys were
distributed over 42 dB channel loss and 200 km of optical fibre. We employed
the differential phase shift quantum key distribution (DPS-QKD) protocol
implemented with a 10-GHz clock frequency, and superconducting single photon
detectors (SSPD) based on NbN nanowire. The SSPD offers a very low dark count
rate (a few Hz) and small timing jitter (60 ps full width at half maximum).
These characteristics allowed us to construct a 10-GHz clock QKD system and
thus distribute secure keys over channel loss of 42 dB. In addition, we
achieved a 17 kbit/s secure key rate over 105 km of optical fibre, which is two
orders of magnitude higher than the previous record, and a 12.1 bit/s secure
key rate over 200 km of optical fibre, which is the longest terrestrial QKD yet
demonstrated. The keys generated in our experiment are secure against both
general collective attacks on individual photons and a specific collective
attack on multi-photons, known as a sequential unambiguous state discrimination
(USD) attack.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:07:01 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Takesue",
"Hiroki",
""
],
[
"Nam",
"Sae Woo",
""
],
[
"Zhang",
"Qiang",
""
],
[
"Hadfield",
"Robert H.",
""
],
[
"Honjo",
"Toshimori",
""
],
[
"Tamaki",
"Kiyoshi",
""
],
[
"Yamamoto",
"Yoshihisa",
""
]
] |
0706.0398 | Harold Steinacker | Harold Steinacker, George Zoupanos | Fermions on spontaneously generated spherical extra dimensions | 34 pages. V2: references added, minor corrections V3: discussion
added, final version | JHEP 0709:017,2007 | 10.1088/1126-6708/2007/09/017 | UWThPh-2007-15 | hep-th hep-ph | null | We include fermions to the model proposed in hep-th/0606021, and obtain a
renormalizable 4-dimensional SU(N) gauge theory which spontaneously generates
fuzzy extra dimensions and behaves like Yang-Mills theory on M^4 \times S^2. We
find a truncated tower of fermionic Kaluza-Klein states transforming under the
low-energy gauge group, which is found to be either SU(n), or SU(n_1) x SU(n_2)
x U(1). The latter case implies a nontrivial U(1) flux on S^2, leading to
would-be zero modes for the bifundamental fermions. In the non-chiral case they
may pair up to acquire a mass, and the emerging picture is that of mirror
fermions. We discuss the possible implementation of a chirality constraint in 6
dimensions, which is nontrivial at the quantum level due to the fuzzy nature of
the extra dimensions.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 16:58:07 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 09:26:54 GMT"
},
{
"version": "v3",
"created": "Thu, 23 Aug 2007 09:07:06 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Steinacker",
"Harold",
""
],
[
"Zoupanos",
"George",
""
]
] |
0706.0399 | Sandhya Choubey | Ram Lal Awasthi, Sandhya Choubey | Confusing Sterile Neutrinos with Deviation from Tribimaximal Mixing at
Neutrino Telescopes | 22 pages, version to appear in Phys. Rev. D | Phys.Rev.D76:113002,2007 | 10.1103/PhysRevD.76.113002 | HRI-P-07-06-001 | hep-ph astro-ph hep-ex | null | We expound the impact of extra sterile species on the ultra high energy
neutrino fluxes in neutrino telescopes. We use three types of well-known flux
ratios and compare the values of these flux ratios in presence of sterile
neutrinos, with those predicted by deviation from the tribimaximal mixing
scheme. We show that in the upcoming neutrino telescopes, its easy to confuse
between the signature of sterile neutrinos with that of the deviation from
tribimaximal mixing. We also show that if the measured flux ratios acquire a
value well outside the range predicted by the standard scenario with three
active neutrinos only, it might be possible to tell the presence of extra
sterile neutrinos by observing ultra high energy neutrinos in future neutrino
telescopes.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:16:32 GMT"
},
{
"version": "v2",
"created": "Wed, 17 Oct 2007 15:44:12 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Awasthi",
"Ram Lal",
""
],
[
"Choubey",
"Sandhya",
""
]
] |
0706.0400 | Xinxian Zheng | Juergen Herzog, Xinxian Zheng | Bounds for Hilbert coefficients | null | null | null | null | math.AC | null | We compute the Hilbert coefficients of a graded module with pure resolution
and discuss lower and upper bounds for these coefficients for arbitrary graded
modules.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:17:46 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Herzog",
"Juergen",
""
],
[
"Zheng",
"Xinxian",
""
]
] |
0706.0401 | Kostyantyn Zheltukhin Dr | Metin Gurses, Ismagil Habibullin and Kostyantyn Zheltukhin | Integrable nonlinear equations on a circle | 23 pages | J. Math. Phys. 48, no. 10, (2007), 102702 | 10.1063/1.2799256 | null | nlin.SI | null | The concept of integrable boundary value problems for soliton equations on
$\mathbb{R}$ and $\mathbb{R}_+$ is extended to bounded regions enclosed by
smooth curves. Classes of integrable boundary conditions on a circle for the
Toda lattice and its reductions are found.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:54:00 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Jun 2007 10:50:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gurses",
"Metin",
""
],
[
"Habibullin",
"Ismagil",
""
],
[
"Zheltukhin",
"Kostyantyn",
""
]
] |
0706.0402 | Jan Rusz | J\'an Rusz, Olle Eriksson, Pavel Nov\'ak, Peter M. Oppeneer | Sum-rules for electron energy-loss near-edge spectra | 4 pages, 1 figure | null | 10.1103/PhysRevB.76.060408 | null | cond-mat.mtrl-sci | null | We derive four sum-rule expressions for spectra measured in electron
energy-loss near edge structure experiments. These sum-rules permit the
determination spin and orbital magnetic moments, spin-orbit interaction and
number of states, analogously to the sum rules of x-ray magnetic circular
dichroism. The derivation of the sum-rules is based on dynamical electron
diffraction theory and the properties of the mixed dynamic form-factor. The
accuracy of the sum-rules is tested by a complete evaluation of the thickness
dependent electron energy-loss spectra for iron, cobalt, and nickel crystals.
We find that the sum-rules reproduce both spin and orbital moments with very
good accuracy. Our results provide a foundation for the use of the energy loss
magnetic chiral dichroism technique as a quantitative probe of element specific
magnetic properties.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:47:48 GMT"
},
{
"version": "v2",
"created": "Wed, 15 Aug 2007 16:07:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rusz",
"Ján",
""
],
[
"Eriksson",
"Olle",
""
],
[
"Novák",
"Pavel",
""
],
[
"Oppeneer",
"Peter M.",
""
]
] |
0706.0403 | Tomasz Rolski | Soeren Asmussen, Pierre Fiorini, Lester Lipsky, Tomasz Rolski, Robert
Sheahan | Asymptotic Behavior of Total Times For Jobs That Must Start Over If a
Failure Occurs | null | null | null | null | math.PR | null | Many processes must complete in the presence of failures. Different systems
respond to task failure in different ways. The system may resume a failed task
from the failure point (or a saved checkpoint shortly before the failure
point), it may give up on the task and select a replacement task from the ready
queue, or it may restart the task. The behavior of systems under the first two
scenarios is well documented, but the third ({\em RESTART}) has resisted
detailed analysis. In this paper we derive tight asymptotic relations between
the distribution of {\em task times} without failures to the {\em total time}
when including failures, for any failure distribution. In particular, we show
that if the task time distribution has an unbounded support then the total time
distribution $H$ is always heavy-tailed. Asymptotic expressions are given for
the tail of $H$ in various scenarios. The key ingredients of the analysis are
the Cram\'er--Lundberg asymptotics for geometric sums and integral asymptotics,
that in some cases are obtained via Tauberian theorems and in some cases by
bare-hand calculations.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 09:58:20 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Asmussen",
"Soeren",
""
],
[
"Fiorini",
"Pierre",
""
],
[
"Lipsky",
"Lester",
""
],
[
"Rolski",
"Tomasz",
""
],
[
"Sheahan",
"Robert",
""
]
] |
0706.0404 | Lo\"ic Bervas | Delphine Lebeugle, Dorothee Colson, Anne Forget, Michel Viret, Pierre
Bonville, Jean-Francis Marucco, Stephane Fusil | Room temperature coexistence of large electric polarization and magnetic
order in BiFeO3 single crystals | 27 pages, 12 figures | null | 10.1103/PhysRevB.76.024116 | SPEC-S07/039 | cond-mat.mtrl-sci | null | From an experimental point of view, room temperature ferroelectricity in
BiFeO3 is raising many questions. Electric measurements made a long time ago on
solid-solutions of BiFeO3 with Pb(Ti,Zr)O3 indicate that a spontaneous electric
polarization exists in BiFeO3 below the Curie temperature TC=1143K. Yet in most
reported works, the synthesised samples are too conductive at room temperature
to get a clear polarization loop in the bulk without any effects of extrinsic
physical or chemical parameters. Surprisingly, up to now there has been no
report of a P(E) (polarization versus electric field) loop at room temperature
on single crystals of BiFeO3. We describe here our procedure to synthesize
ceramics and to grow good quality sizeable single crystals by a flux method. We
demonstrate that BiFeO3 is indeed ferroelectric at room-temperature through
evidence by Piezoresponse Force Microscopy and P(E) loops. The polarization is
found to be large, around 60 microC/cm2, a value that has only been reached in
thin films. Magnetic measurements using a SQUID magnetometer and Mossbauer
spectroscopy are also presented. The latter confirms the results of NMR
measurements concerning the anisotropy of the hyperfine field attributed to the
magnetic cycloidal structure.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:07:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lebeugle",
"Delphine",
""
],
[
"Colson",
"Dorothee",
""
],
[
"Forget",
"Anne",
""
],
[
"Viret",
"Michel",
""
],
[
"Bonville",
"Pierre",
""
],
[
"Marucco",
"Jean-Francis",
""
],
[
"Fusil",
"Stephane",
""
]
] |
0706.0405 | Aiguo Xu Prof. Dr. | X.F.Pan, Aiguo Xu, Guangcai Zhang, Song Jiang | Lattice Boltzmann Approach to High-Speed Compressible Flows | Figs.11 and 12 in JPEG format. Int. J. Mod. Phys. C (to appear) | International Journal of Modern Physics C Vol.18, No.11 (2007)
1747-1764. | 10.1142/S0129183107011716 | null | cond-mat.soft cond-mat.stat-mech | null | We present an improved lattice Boltzmann model for high-speed compressible
flows. The model is composed of a discrete-velocity model by Kataoka and
Tsutahara [Phys. Rev. E \textbf{69}, 056702 (2004)] and an appropriate
finite-difference scheme combined with an additional dissipation term. With the
dissipation term parameters in the model can be flexibly chosen so that the von
Neumann stability condition is satisfied. The influence of the various model
parameters on the numerical stability is analyzed and some reference values of
parameter are suggested. The new scheme works for both subsonic and supersonic
flows with a Mach number up to 30 (or higher), which is validated by well-known
benchmark tests. Simulations on Riemann problems with very high ratios
($1000:1$) of pressure and density also show good accuracy and stability.
Successful recovering of regular and double Mach shock reflections shows the
potential application of the lattice Boltzmann model to fluid systems where
non-equilibrium processes are intrinsic. The new scheme for stability can be
easily extended to other lattice Boltzmann models.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:07:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pan",
"X. F.",
""
],
[
"Xu",
"Aiguo",
""
],
[
"Zhang",
"Guangcai",
""
],
[
"Jiang",
"Song",
""
]
] |
0706.0406 | Kavita Jain | Kavita Jain | Evolutionary dynamics of the most populated genotype on rugged fitness
landscapes | Minor changes. To appear in Phys Rev E | Phys. Rev. E 76, 031922 (2007) | 10.1103/PhysRevE.76.031922 | null | q-bio.PE cond-mat.stat-mech | null | We consider an asexual population evolving on rugged fitness landscapes which
are defined on the multi-dimensional genotypic space and have many local
optima. We track the most populated genotype as it changes when the population
jumps from a fitness peak to a better one during the process of adaptation.
This is done using the dynamics of the shell model which is a simplified
version of the quasispecies model for infinite populations and standard
Wright-Fisher dynamics for large finite populations. We show that the
population fraction of a genotype obtained within the quasispecies model and
the shell model match for fit genotypes and at short times, but the dynamics of
the two models are identical for questions related to the most populated
genotype. We calculate exactly several properties of the jumps in infinite
populations some of which were obtained numerically in previous works. We also
present our preliminary simulation results for finite populations. In
particular, we measure the jump distribution in time and find that it decays as
$t^{-2}$ as in the quasispecies problem.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:09:26 GMT"
},
{
"version": "v2",
"created": "Sat, 11 Aug 2007 16:13:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jain",
"Kavita",
""
]
] |
0706.0407 | Kambiz Fathi | Kambiz Fathi, John E. Beckman, Claude Carignan, Olivier Hernandez | Fabry-Perot Interferometry and Dynamics of Spiral Galaxies | To appear in the proceedings for "Pathways Through an Eclectic
Universe", Editors: Johan Knapen, Terry Mahoney, and Alexandre Vazdekis | null | null | null | astro-ph | null | We present two-dimensional Febry-Perot observations of emission-line
distribution and kinematics in nearly spiral galaxies. We have developed and
demonstrated the utility of a number of analysis tools which have general
applicability, but which we have, so far, applied to only one galaxy (M 74,
Fathi et al. 2007). In this galaxy, we have found kinematic signatures of
radial motions caused by an m=2 perturbation. Such a perturbation may well be
responsible for the inflow of material forming the nuclear ring and the inner
rapidly rotating disc-like structure. The latter, in turn, could help build a
pseudo-bulge. In the second paper in this series, we will apply the kinematic
analysis tools to a sample of 9 late-type spiral galaxies observed with the
FaNTOmM Fabry-Perot spectrometer at the Canada-France-Hawaii telescope.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:16:26 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Fathi",
"Kambiz",
""
],
[
"Beckman",
"John E.",
""
],
[
"Carignan",
"Claude",
""
],
[
"Hernandez",
"Olivier",
""
]
] |
0706.0408 | G\'erard Endimioni | G. Endimioni | Automorphisms fixing every normal subgroup of a nilpotent-by-abelian
group | 6 pages | null | null | null | math.GR | null | Among other things, we prove that the group of automorphisms fixing every
normal subgroup of a nilpotent-by-abelian group is nilpotent-by-metabelian. In
particular, the group of automorphisms fixing every normal subgroup of a
metabelian group is soluble of derived length at most 3. An example shows that
this bound cannot be improved.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:18:32 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Endimioni",
"G.",
""
]
] |
0706.0409 | Isao Kishimoto | Isao Kishimoto, Yoji Michishita | Comments on Solutions for Nonsingular Currents in Open String Field
Theories | 23 pages; v2: PTPTeX, typos corrected | Prog.Theor.Phys.118:347-369,2007 | 10.1143/PTP.118.347 | KEK-TH-1156, RIKEN-TH-102 | hep-th | null | We investigate analytic solutions to Witten's bosonic string field theory and
Berkovits' WZW-type superstring field theory. We construct solutions with
parameters out of simpler ones, using a commutative monoid that includes the
family of wedge states. Our solutions are generalizations of solutions for
marginal deformations by nonsingular currents, and can also reproduce Schnabl's
tachyon vacuum solution in bosonic string field theory. This implies that such
known solutions are generated from simple solutions which are based on the
identity state. We also discuss gauge transformations and induced field
redefinitions for our solutions in both bosonic and super string field theory.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 10:27:48 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 11:19:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kishimoto",
"Isao",
""
],
[
"Michishita",
"Yoji",
""
]
] |
0706.0410 | Sushil Srivastava | S. K. Srivastava | Curvature Inspired Cosmological Scenario | 19 Pages. To appear in Int. J. Thro. Phys | Int.J.Theor.Phys.47:1966-1978,2008 | 10.1007/s10773-007-9640-7 | null | hep-th astro-ph gr-qc | null | Using modified gravity with non-linear terms of curvature, $R^2$ and $R^{(r
+2)}$ (with $r$ being the positive real number and $R$ being the scalar
curvature), cosmological scenario,beginning at the Planck scale, is obtained.
Here, a unified picture of cosmology is obtained from $f(R)-$ gravity. In this
scenario, universe begins with power-law inflation, followed by deceleration
and acceleration in the late universe as well as possible collapse of the
universe in future. It is different from $f(R)-$ dark energy models with
non-linear curvature terms assumed as dark energy. Here, dark energy terms are
induced by linear as well as non-linear terms of curvature in Friedmann
equation being derived from modified gravity.It is also interesting to see
that, in this model, dark radiation and dark matter terms emerge spontaneously
from the gravitational sector. It is found that dark energy, obtained here,
behaves as quintessence in the early universe and phantom in the late universe.
Moreover, analogous to brane-tension in brane-gravity inspired Friedmann
equation, a tension term $\lambda$ arises here being called as cosmic tension.
It is found that, in the late universe, Friedmann equation (obtained here)
contains a term $- \rho^2/2\lambda$ ($\rho$ being the phantom energy density)
analogous to a similar term in Friedmann equation with loop quantum effects, if
$\lambda > 0$ and brane-gravity correction when $\lambda < 0.$
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 11:03:17 GMT"
},
{
"version": "v2",
"created": "Sun, 6 Jan 2008 03:42:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Srivastava",
"S. K.",
""
]
] |
0706.0411 | Javier Mas | Karl Landsteiner, Javier Mas | The shear viscosity of the non-commutative plasma | 17 pages. v2: reference added | JHEP 0707:088,2007 | 10.1088/1126-6708/2007/07/088 | null | hep-th | null | We compute the shear viscosity of the non-commutative N=4 super Yang-Mills
quantum field theory at strong coupling using the dual supergravity background.
Special interest derives from the fact that the background presents an
intrinsic anisotropy in space through the distinction of commutative and
non-commutative directions. Despite this anisotropy the analysis exhibits the
ubiquitous result \eta/s = 1/4\pi for two different shear channels. In order to
derive this result, we show that the boundary energy momentum tensor must
couple to the open string metric. As a byproduct we compute the renormalised
holographic energy momentum tensor and show that it coincides with one in the
commutative theory.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 13:35:41 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 08:39:48 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Landsteiner",
"Karl",
""
],
[
"Mas",
"Javier",
""
]
] |
0706.0412 | Peter Coles | Peter Coles and Pirin Erdogdu (School of Physics & Astronomy,
University of Nottingham, Nottingham, UK) | Scale-dependent Galaxy Bias | 14 pages, 2 figures, typos corrected, discussion added and references
corrected; matches version accepted by JCAP | JCAP0710:007,2007 | 10.1088/1475-7516/2007/10/007 | null | astro-ph | null | We present a simple heuristic model to demonstrate how feedback related to
the galaxy formation process can result in a scale-dependent bias of mass
versus light, even on very large scales. The model invokes the idea that
galaxies form initially in locations determined by the local density field, but
the subsequent formation of galaxies is also influenced by the presence of
nearby galaxies that have already formed. The form of bias that results
possesses some features that are usually described in terms of stochastic
effects, but our model is entirely deterministic once the density field is
specified. Features in the large-scale galaxy power spectrum (such as wiggles
that might in an extreme case mimic the effect of baryons on the primordial
transfer function) could, at least in principle, arise from spatial modulations
of the galaxy formation process that arise naturally in our model. We also show
how this fully deterministic model gives rise to apparently stochasticity in
the galaxy distribution.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 11:37:01 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Sep 2007 13:53:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Coles",
"Peter",
"",
"School of Physics & Astronomy,\n University of Nottingham, Nottingham, UK"
],
[
"Erdogdu",
"Pirin",
"",
"School of Physics & Astronomy,\n University of Nottingham, Nottingham, UK"
]
] |
0706.0413 | Pawe{\l} Sztonyk dr | Pawe{\l} Sztonyk | Regularity of harmonic functions for anisotropic fractional Laplacian | 36 pages | null | null | null | math.PR | null | We prove that bounded harmonic functions of anisotropic fractional Laplacians
are H\"older continuous under mild regularity assumptions on the corresponding
L\'evy measure. Under some stronger assumptions the Green function, Poisson
kernel and the harmonic functions are even differentiable of order up to three.
| [
{
"version": "v1",
"created": "Mon, 4 Jun 2007 11:45:43 GMT"
}
] | 2007-06-05T00:00:00 | [
[
"Sztonyk",
"Paweł",
""
]
] |
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