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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.3114 | Matteo Ortisi | Matteo Ortisi | Polynomial rate convergence to an invariant measure for the continuum
time limit of the Minority Game | 13 pages, content changed | Journal of Applied Probability Vol.45 N.2, 2008 | null | null | math.PR | null | In this paper we show that the continuum time version of the Minority Game
satisfies the criteria for the application of a theorem on the existence of an
invariant measure. We consider the special case of a game with "sufficiently"
asymmetric initial condition where the number of possible choices for each
individual is S=2 and $\Gamma<+\infty$. An upper bound for the asymptotic
behavior, as the number of agents grows to infinity, of the waiting time for
reaching the stationary state is then obtained.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:10:50 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Apr 2008 16:52:07 GMT"
}
] | 2008-04-17T00:00:00 | [
[
"Ortisi",
"Matteo",
""
]
] |
0706.3115 | Bernhard Lamel | Bernhard Lamel, Nordine Mir | Finite jet determination of CR mappings | Article in press at Adv. Math | Adv. Math., 216(1), (2007), 153--177. | 10.1016/j.aim.2007.05.007 | null | math.CV | null | We prove the following finite jet determination result for CR mappings: Given
a smooth generic submanifold M of C^N, N >= 2, which is essentially finite and
of finite type at each of its points, for every point p on M there exists an
integer l(p), depending upper-semicontinuously on p, such that for every smooth
generic submanifold M' of C^N of the same dimension as M, if h_1 and h_2:
(M,p)->M' are two germs of smooth finite CR mappings with the same l(p) jet at
p, then necessarily their k-jets agree for all positive integers k. In the
hypersurface case, this result provides several new unique jet determination
properties for holomorphic mappings at the boundary in the real-analytic case;
in particular, it provides the finite jet determination of arbitrary
real-analytic CR mappings between real-analytic hypersurfaces in C^N of
D'Angelo finite type. It also yields a new boundary version of H. Cartan's
uniqueness theorem: if Omega and Omega' are two bounded domains in C^N with
smooth real-analytic boundary, then there exists an integer k, depending only
on the boundary of Omega, such that if H_1 and H_2: Omega -> Omega' are two
proper holomorphic mappings extending smoothly up to the boundary of Omega near
some point boundary point p and agreeing up to order k at p, then necessarily
H_1=H_2.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:23:52 GMT"
}
] | 2007-09-18T00:00:00 | [
[
"Lamel",
"Bernhard",
""
],
[
"Mir",
"Nordine",
""
]
] |
0706.3116 | Daniel Andr\'en | Daniel Andren | Series expansion for the density of states of the Ising and Potts models | null | null | null | null | cond-mat.str-el cond-mat.stat-mech | null | An approximation of the density of states for the Ising and Potts models
based on the high- and low-temperature series are developed.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:09:57 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Andren",
"Daniel",
""
]
] |
0706.3117 | Andrei Sobolev M. | A.M. Sobolev, D.M. Cragg, S.P. Ellingsen, M.J. Gaylard, S. Goedhart,
C. Henkel, M.S. Kirsanova, A.B. Ostrovskii, N.V. Pankratova, O.V. Shelemei,
D.J. van der Walt, T.S. Vasyunina, M.A. Voronkov | How do methanol masers manage to appear in the youngest star vicinities
and isolated molecular clumps? | 8 pages, 4 figures, invited presentation at IAU242 "Astrophysical
Masers and their environments" | null | 10.1017/S1743921307012616 | null | astro-ph | null | General characteristics of methanol (CH3OH) maser emission are summarized. It
is shown that methanol maser sources are concentrated in the spiral arms. Most
of the methanol maser sources from the Perseus arm are associated with embedded
stellar clusters and a considerable portion is situated close to compact HII
regions. Almost 1/3 of the Perseus Arm sources lie at the edges of optically
identified HII regions which means that massive star formation in the Perseus
Arm is to a great extent triggered by local phenomena. A multiline analysis of
the methanol masers allows us to determine the physical parameters in the
regions of maser formation. Maser modelling shows that class II methanol masers
can be pumped by the radiation of the warm dust as well as by free-free
emission of a hypercompact region hcHII with a turnover frequency exceeding 100
GHz. Methanol masers of both classes can reside in the vicinity of hcHIIs.
Modelling shows that periodic changes of maser fluxes can be reproduced by
variations of the dust temperature by a few percent which may be caused by
variations in the brightness of the central young stellar object reflecting the
character of the accretion process. Sensitive observations have shown that the
masers with low flux densities can still have considerable amplification
factors. The analysis of class I maser surveys allows us to identify four
distinct regimes that differ by the series of their brightest lines.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:33:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sobolev",
"A. M.",
""
],
[
"Cragg",
"D. M.",
""
],
[
"Ellingsen",
"S. P.",
""
],
[
"Gaylard",
"M. J.",
""
],
[
"Goedhart",
"S.",
""
],
[
"Henkel",
"C.",
""
],
[
"Kirsanova",
"M. S.",
""
],
[
"Ostrovskii",
"A. B.",
""
],
[
"Pankratova",
"N. V.",
""
],
[
"Shelemei",
"O. V.",
""
],
[
"van der Walt",
"D. J.",
""
],
[
"Vasyunina",
"T. S.",
""
],
[
"Voronkov",
"M. A.",
""
]
] |
0706.3118 | I.K. Gopalakrishnan | O.D. Jayakumar, I.K. Gopalakrishnan, S.K. Kulshreshtha, Amita Gupta,
K.V. Rao, D. Louzguine, Akihisa Inoue, P. Glans, Jinghua Guo, Kousik Samanta,
M.K. Singh, R.S. Katiyar | The structural and magnetic properties of (In1-xFex)2O3 (0.0 <= x <=
0.25) system : prepared by gel combustion method | 9 pages 3 figures | Applied Physics Letters 91(23rd July 2007) | 10.1063/1.2757589 | null | cond-mat.mtrl-sci | null | (In1-xFex)2O3 polycrystalline samples with x = (0.0, 0.05, 0.10, 0.15, 0.20
and 0.25) have been synthesized by a gel combustion method. Reitveld refinement
analysis of X raydiffraction data indicated the formation of single phase cubic
bixbyite structure without any parasitic phases. This observation is further
confirmed by high resolution transmission electron microscopy (HRTEM) imaging,
and indexing of the selected-area electron diffraction (SAED) patterns, X-ray
Absorption Spectroscopy (XAS) and Raman Spectroscopy. DC Magnetization studies
as a function of temperature and field indicatethat they are ferromagnetic with
Curie temperature (TC) well above room temperature.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:41:50 GMT"
}
] | 2007-07-25T00:00:00 | [
[
"Jayakumar",
"O. D.",
""
],
[
"Gopalakrishnan",
"I. K.",
""
],
[
"Kulshreshtha",
"S. K.",
""
],
[
"Gupta",
"Amita",
""
],
[
"Rao",
"K. V.",
""
],
[
"Louzguine",
"D.",
""
],
[
"Inoue",
"Akihisa",
""
],
[
"Glans",
"P.",
""
],
[
"Guo",
"Jinghua",
""
],
[
"Samanta",
"Kousik",
""
],
[
"Singh",
"M. K.",
""
],
[
"Katiyar",
"R. S.",
""
]
] |
0706.3119 | Paul de Medeiros | Jan de Boer, Paul de Medeiros, Sheer El-Showk, Annamaria Sinkovics | G2 Hitchin functionals at one loop | 58 pages, LaTeX; v2: Acknowledgments added | Class.Quant.Grav.25:075006,2008 | 10.1088/0264-9381/25/7/075006 | DAMTP-2007-54, EMPG-07-10, ITFA-07-25 | hep-th | null | We consider the quantization of the effective target space description of
topological M-theory in terms of the Hitchin functional whose critical points
describe seven-manifolds with G2 structure. The one-loop partition function for
this theory is calculated and an extended version of it, that is related to
generalized G2 geometry, is compared with the topological G2 string. We relate
the reduction of the effective action for the extended G2 theory to the Hitchin
functional description of the topological string in six dimensions. The
dependence of the partition functions on the choice of background G2 metric is
also determined.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:12:31 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 13:21:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"de Boer",
"Jan",
""
],
[
"de Medeiros",
"Paul",
""
],
[
"El-Showk",
"Sheer",
""
],
[
"Sinkovics",
"Annamaria",
""
]
] |
0706.3120 | Oleg Andreev | Oleg Andreev | Some Thermodynamic Aspects of Pure Glue, Fuzzy Bags and Gauge/String
Duality | 10 pages, 5 figures | Phys.Rev.D76:087702,2007 | 10.1103/PhysRevD.76.087702 | MPP-2007-72 | hep-ph hep-lat hep-th nucl-th | null | The thermodynamic properties of a SU(3) gauge theory without quarks are
calculated using a string formulation for 1.2T_c < T < 3T_c. The results are in
good agreement with the lattice data. We also comment on SU(N) gauge theories.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:44:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Andreev",
"Oleg",
""
]
] |
0706.3121 | Francisco Santos | Vincent Pilaud and Francisco Santos | Multi-triangulations as complexes of star polygons | 40 pages, 24 figures; added references, update Section 8 | Discrete Comput. Geom., 41(2):284-317, 2009 | 10.1007/s00454-008-9078-6 | null | math.CO | null | Maximal $(k+1)$-crossing-free graphs on a planar point set in convex
position, that is, $k$-triangulations, have received attention in recent
literature, with motivation coming from several interpretations of them.
We introduce a new way of looking at $k$-triangulations, namely as complexes
of star polygons. With this tool we give new, direct, proofs of the fundamental
properties of $k$-triangulations, as well as some new results. This
interpretation also opens-up new avenues of research, that we briefly explore
in the last section.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:46:49 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 17:46:15 GMT"
}
] | 2012-06-14T00:00:00 | [
[
"Pilaud",
"Vincent",
""
],
[
"Santos",
"Francisco",
""
]
] |
0706.3122 | Huiming Yang | H. M. Yang, Y. S. Ting, and K. Y. Michael Wong | Effects of payoff functions and preference distributions in an adaptive
population | null | Phys. Rev. E 77, 031116 (2008) | 10.1103/PhysRevE.77.031116 | null | q-fin.ST physics.soc-ph | null | Adaptive populations such as those in financial markets and distributed
control can be modeled by the Minority Game. We consider how their dynamics
depends on the agents' initial preferences of strategies, when the agents use
linear or quadratic payoff functions to evaluate their strategies. We find that
the fluctuations of the population making certain decisions (the volatility)
depends on the diversity of the distribution of the initial preferences of
strategies. When the diversity decreases, more agents tend to adapt their
strategies together. In systems with linear payoffs, this results in dynamical
transitions from vanishing volatility to a non-vanishing one. For low signal
dimensions, the dynamical transitions for the different signals do not take
place at the same critical diversity. Rather, a cascade of dynamical
transitions takes place when the diversity is reduced. In contrast, no phase
transitions are found in systems with the quadratic payoffs. Instead, a basin
boundary of attraction separates two groups of samples in the space of the
agents' decisions. Initial states inside this boundary converge to small
volatility, while those outside diverge to a large one. Furthermore, when the
preference distribution becomes more polarized, the dynamics becomes more
erratic. All the above results are supported by good agreement between
simulations and theory.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 10:56:03 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Dec 2007 18:11:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yang",
"H. M.",
""
],
[
"Ting",
"Y. S.",
""
],
[
"Wong",
"K. Y. Michael",
""
]
] |
0706.3123 | Yasuyuki Tanaka | Y. T. Tanaka, T. Terasawa, N. Kawai, A. Yoshida, I. Yoshikawa, Y.
Saito, T. Takashima, and T. Mukai | Comparative study of the inial spikes of SGR giant flares in 1998 and
2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large
scale fracturing of magnetar's crust? | 12 pages, 3 figures, accepted by ApJL | null | 10.1086/521025 | null | astro-ph | null | We present the unsaturated peak profile of SGR 1900+14 giant flare on 1998
August 27. This was obtained by particle counters of the Low Energy Particle
instrument onboard the GEOTAIL spacecraft. The observed peak profile revealed
four characteristic structures: initial steep rise, intermediate rise to the
peak, exponential decay and small hump in the decay phase. From this light
curve, we found that the isotropic peak luminosity was $2.3\times10^{46}$ erg
s$^{-1}$ and the total energy was $4.3 \times 10^{44}$ erg s$^{-1}$ ($E\gtrsim$
50 keV), assuming that the distance to SGR 1900+14 is 15 kpc and that the
spectrum is optically thin thermal bremsstrahlung with $kT =$ 240 keV. These
are consistent with the previously reported lower limits derived from Ulysses
and Konus-Wind observations. A comparative study of the initial spikes of SGR
1900+14 giant flare in 1998 and SGR 1806-20 in 2004 is also presented. The
timescale of the initial steep rise shows the magnetospheric origin, while the
timescale of the intermediate rise to the peak indicates that it originates
from the crustal fracturing. Finally, we argue that the four structures and
their corresponding timescales provide a clue to identify extragalactic SGR
giant flares among short GRBs.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:15:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tanaka",
"Y. T.",
""
],
[
"Terasawa",
"T.",
""
],
[
"Kawai",
"N.",
""
],
[
"Yoshida",
"A.",
""
],
[
"Yoshikawa",
"I.",
""
],
[
"Saito",
"Y.",
""
],
[
"Takashima",
"T.",
""
],
[
"Mukai",
"T.",
""
]
] |
0706.3124 | Andreas Knauf | Andreas Knauf, Markus Krapf | The Non-Trapping Degree of Scattering | 25 pages, 1 figure Revised and enlarged version, containing more
detailed proofs and remarks | null | 10.1088/0951-7715/21/9/005 | null | math-ph math.MP | null | We consider classical potential scattering. If no orbit is trapped at energy
E, the Hamiltonian dynamics defines an integer-valued topological degree. This
can be calculated explicitly and be used for symbolic dynamics of
multi-obstacle scattering.
If the potential is bounded, then in the non-trapping case the boundary of
Hill's Region is empty or homeomorphic to a sphere.
We consider classical potential scattering. If at energy E no orbit is
trapped, the Hamiltonian dynamics defines an integer-valued topological degree
deg(E) < 2. This is calculated explicitly for all potentials, and exactly the
integers < 2 are shown to occur for suitable potentials.
The non-trapping condition is restrictive in the sense that for a bounded
potential it is shown to imply that the boundary of Hill's Region in
configuration space is either empty or homeomorphic to a sphere.
However, in many situations one can decompose a potential into a sum of
non-trapping potentials with non-trivial degree and embed symbolic dynamics of
multi-obstacle scattering. This comprises a large number of earlier results,
obtained by different authors on multi-obstacle scattering.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:40:44 GMT"
},
{
"version": "v2",
"created": "Tue, 13 Nov 2007 18:16:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Knauf",
"Andreas",
""
],
[
"Krapf",
"Markus",
""
]
] |
0706.3125 | Vitaly Bornyakov | V.G. Bornyakov, E.V. Lushchevskaya | Spatial string tension in $N_f=2$ lattice QCD at finite temperature | 8 pages, 2 figures, numerical results and both figures slightly
changed, comparison with theoretical predictions added, values of the ratio
T/T_{pc} slightly changed | Phys.Atom.Nucl.72:257-260,2009 | 10.1134/S1063778809020082 | null | hep-lat | null | The spatial string tension across a crossover from the low temperature phase
to the high temperature phase is computed in QCD with two flavors of
non-perturbatively improved Wilson fermions at small lattice spacing a \sim
0.12fm. We find that in the low temperature phase spatial string tension agrees
well with zero temperature string tension. Furthermore, it does not show
increasing for temperatures up to T = 1.36 T_{pc}, the highest temperature
considered. Our results agree with some theoretical predictions.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:59:10 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Mar 2008 16:18:11 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Bornyakov",
"V. G.",
""
],
[
"Lushchevskaya",
"E. V.",
""
]
] |
0706.3126 | Anatoly Spitkovsky | Anatoly Spitkovsky (Princeton University) | On the structure of relativistic collisionless shocks in electron-ion
plasmas | 4 pages, 3 figures; submitted to ApJ Letters | null | 10.1086/527374 | null | astro-ph | null | Relativistic collisionless shocks in electron-ion plasma are thought to occur
in the afterglow phase of Gamma-Ray Bursts (GRBs), and in other environments
where relativistic flows interact with the interstellar medium. A particular
regime of shocks in an unmagnetized plasma has generated much interest for GRB
applications. In this paper we present ab-initio particle-in-cell simulations
of unmagnetized relativistic electron-ion shocks. Using long-term
2.5-dimensional simulations with ion-electron mass ratios from 16 to 1000 we
resolve the shock formation and reach a steady-state shock structure beyond the
initial transient. We find that even at high ion-electron mass ratios initially
unmagnetized shocks can be effectively mediated by the ion Weibel instability
with a typical shock thickness of ~50 ion skin-depths. Upstream of the shock
the interaction with merging ion current filaments heats the electron
component, so that the postshock flow achieves near equipartition between the
ions and electrons, with electron temperature reaching 50% of the ion
temperature. This energy exchange helps to explain the large electron energy
fraction inferred from GRB afterglow observations.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:24:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Spitkovsky",
"Anatoly",
"",
"Princeton University"
]
] |
0706.3127 | Karim Benakli | Karim Benakli and Cesar Moura | Brane-Worlds Pseudo-Goldstinos | 50 pages with 1 figure. Dedicated to M. Quiros for his 60th birthday.
Refs added and typos corrected. Version to appear in Nuclear Physics B. One
ref added | Nucl.Phys.B791:125-163,2008 | 10.1016/j.nuclphysb.2007.09.010 | null | hep-th hep-ph | null | We consider a space-time with extra dimensions containing sectors, branes and
bulk, that communicate only through gravitational interactions. In each sector,
if considered separately, supersymmetry could be spontaneously broken, leading
to the appearance of Goldstinos. However, when taken all together, only certain
combinations of the latter states turn out to be true ``would be Goldstinos'',
eaten by the gravitinos. The other (orthogonal) combinations, we call
pseudo-Goldstinos, remain in the low energy spectrum. We discuss explicitly how
this happen in the simplest set-up of five-dimensional space compactified on
S^1/Z_2 . Our results divide into two parts that can be considered separately.
First, we build an extension of the bulk five-dimensional supergravity, by a
set of new auxiliary fields, that allows coupling it to branes where
supersymmetry is spontaneously broken. Second, we discuss in details the super
Higgs mechanism in the R_\xi and unitary gauges, in the presence of both of a
bulk Scherk-Schwarz mechanism and brane localized F-terms. This leads us to
compute the gravitino mass and provide explicit formulae for the
pseudo-Goldstinos spectrum.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:44:39 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 12:30:21 GMT"
},
{
"version": "v3",
"created": "Mon, 15 Oct 2007 12:20:24 GMT"
},
{
"version": "v4",
"created": "Thu, 10 Jan 2008 13:36:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Benakli",
"Karim",
""
],
[
"Moura",
"Cesar",
""
]
] |
0706.3128 | Ergash Tursunov M. | E.M. Tursunov (PNTPM, ULB, Brussels & INP, Tashkent), P. Descouvemont
(PNTPM, ULB, Brussels) and D. Baye (ULB, Brussels) | Gamma-delayed deuteron emission of the 6Li (0+;T=1) halo state | 20 pages, 5 figures. Accepted for publication in Nucl. Phys. A., 2007 | Nucl.Phys. A793:52-66, 2007 | 10.1016/j.nuclphysa.2007.06.002 | null | nucl-th | null | M1 transitions from the $^6$Li($0^+;T=1$) state at 3.563 MeV to the
$^6$Li($1^+$) ground state and to the $\alpha+d$ continuum are studied in a
three-body model. The bound states are described as an $\alpha+n+p$ system in
hyperspherical coordinates on a Lagrange mesh. The ground-state magnetic moment
and the gamma width of the $^6$Li(0$^+$) resonance are well reproduced. The
halo-like structure of the $^6$Li$(0^+)$ resonance is confirmed and is probed
by the M1 transition probability to the $\alpha+d$ continuum. The spectrum is
sensitive to the description of the $\alpha+d$ phase shifts. The corresponding
gamma width is around 1.0 meV, with optimal potentials. Charge symmetry is
analyzed through a comparison with the $\beta$-delayed deuteron spectrum of
$^6$He. In $^6$He, a nearly perfect cancellation effect between short-range and
halo contributions was found. A similar analysis for the $^6$Li($0^+;T=1$)
$\gamma$ decay is performed; it shows that charge-symmetry breaking at large
distances, due to the different binding energies and to different charges,
reduces this effect. The present branching ratio $\Gamma_{\gamma}(0^+\to
\alpha+d)/\Gamma_{\gamma}(0^+\to1^+)\approx 1.3\times 10^{-4}$ should be
observable with current experimental facilities.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:52:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tursunov",
"E. M.",
"",
"PNTPM, ULB, Brussels & INP, Tashkent"
],
[
"Descouvemont",
"P.",
"",
"PNTPM, ULB, Brussels"
],
[
"Baye",
"D.",
"",
"ULB, Brussels"
]
] |
0706.3129 | Aris L. Moustakas | Pavlos Kazakopoulos and Aris L. Moustakas | Closed-Form Density of States and Localization Length for a
Non-Hermitian Disordered System | 5 pages, 1 figure | null | 10.1103/PhysRevE.78.016603 | null | cond-mat.dis-nn cond-mat.stat-mech cs.IT math.IT nlin.SI | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We calculate the Lyapunov exponent for the non-Hermitian Zakharov-Shabat
eigenvalue problem corresponding to the attractive non-linear Schroedinger
equation with a Gaussian random pulse as initial value function. Using an
extension of the Thouless formula to non-Hermitian random operators, we
calculate the corresponding average density of states. We analyze two cases,
one with circularly symmetric complex Gaussian pulses and the other with real
Gaussian pulses. We discuss the implications in the context of the information
transmission through non-linear optical fibers.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 11:57:40 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jun 2008 14:00:53 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Kazakopoulos",
"Pavlos",
""
],
[
"Moustakas",
"Aris L.",
""
]
] |
0706.3130 | Salvatore Capozziello | S. A. Ali, C. Cafaro, S. Capozziello, Ch. Corda | Abelian Magnetic Monopoles and Topologically Massive Vector Bosons in
Scalar-Tensor Gravity with Torsion Potential | 18 pages, no figures | Int. J. Mod. Phys. A23, 4315 (2008) | 10.1142/S0217751X08041438 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A Lagrangian formulation describing the electromagnetic interaction -
mediated by topologically massive vector bosons - between charged, spin-(1/2)
fermions with an abelian magnetic monopole in a curved spacetime with
non-minimal coupling and torsion potential is presented. The covariant field
equations are obtained. The issue of coexistence of massive photons and
magnetic monopoles is addressed in the present framework. It is found that
despite the topological nature of photon mass generation in curved spacetime
with isotropic dilaton field, the classical field theory describing the
nonrelativistic electromagnetic interaction between a point-like electric
charge and magnetic monopole is inconsistent.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:00:21 GMT"
},
{
"version": "v2",
"created": "Wed, 27 May 2009 16:02:32 GMT"
}
] | 2009-05-27T00:00:00 | [
[
"Ali",
"S. A.",
""
],
[
"Cafaro",
"C.",
""
],
[
"Capozziello",
"S.",
""
],
[
"Corda",
"Ch.",
""
]
] |
0706.3131 | Laurent Bartholdi | Bettina Eick, Ren\'e Hartung, Laurent Bartholdi | A nilpotent quotient algorithm for L-presented groups | null | Internat. J. Algebra Comput. 18 (2008), no. 8, 1321--1344 | 10.1142/S0218196708004871 | null | math.GR | null | The main part of this paper contains a description of a nilpotent quotient
algorithm for L-presented groups and a report on applications of its
implementation in the computer algebra system GAP. The appendix introduces two
new infinite series of L-presented groups. Apart from being of interest in
their own right, these new L-presented groups serve as examples for
applications of the nilpotent quotient algorithm.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:25:15 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 18:10:46 GMT"
}
] | 2009-11-27T00:00:00 | [
[
"Eick",
"Bettina",
""
],
[
"Hartung",
"René",
""
],
[
"Bartholdi",
"Laurent",
""
]
] |
0706.3132 | Paulo Condado | Paulo A. Condado and Fernando G. Lobo | EasyVoice: Integrating voice synthesis with Skype | null | null | null | null | cs.CY cs.HC | null | This paper presents EasyVoice, a system that integrates voice synthesis with
Skype. EasyVoice allows a person with voice disabilities to talk with another
person located anywhere in the world, removing an important obstacle that
affect these people during a phone or VoIP-based conversation.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:04:40 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Condado",
"Paulo A.",
""
],
[
"Lobo",
"Fernando G.",
""
]
] |
0706.3133 | David Petrosyan | David Petrosyan | Tunable photonic band gaps with coherently driven atoms in optical
lattices | null | Phys. Rev. A 76, 053823 (2007) | 10.1103/PhysRevA.76.053823 | null | quant-ph | null | Optical lattice loaded with cold atoms can exhibit a tunable photonic band
gap for a weak probe field under the conditions of electromagnetically induced
transparency. This system possesses a number of advantageous properties,
including reduced relaxation of Raman coherence and the associated probe
absorption, and simultaneous enhancement of the index modulation and the
resulting reflectivity of the medium. This flexible system has a potential to
serve as a testbed of various designs for the linear and nonlinear photonic
band gap materials at a very low light level and can be employed for realizing
deterministic entanglement between weak quantum fields.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:07:33 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Petrosyan",
"David",
""
]
] |
0706.3134 | Philip Candelas | Philip Candelas, Xenia de la Ossa, Yang-Hui He, Balazs Szendroi | Triadophilia: A Special Corner in the Landscape | 41 pages 4 pdf figures, one is large. Improved discussion of the
Gross-Popescu manifolds, Figure 4 added, additions to Table 1 and other minor
corrections | Adv.Theor.Math.Phys.12:2,2008 | null | null | hep-th astro-ph hep-ph math.AG | null | It is well known that there are a great many apparently consistent vacua of
string theory. We draw attention to the fact that there appear to be very few
Calabi--Yau manifolds with the Hodge numbers h^{11} and h^{21} both small. Of
these, the case (h^{11}, h^{21})=(3,3) corresponds to a manifold on which a
three generation heterotic model has recently been constructed. We point out
also that there is a very close relation between this manifold and several
familiar manifolds including the `three-generation' manifolds with \chi=-6 that
were found by Tian and Yau, and by Schimmrigk, during early investigations. It
is an intriguing possibility that we may live in a naturally defined corner of
the landscape. The location of these three generation models with respect to a
corner of the landscape is so striking that we are led to consider the
possibility of transitions between heterotic vacua. The possibility of these
transitions, that we here refer to as transgressions, is an old idea that goes
back to Witten. Here we apply this idea to connect three generation vacua on
different Calabi-Yau manifolds.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 08:53:15 GMT"
},
{
"version": "v2",
"created": "Sun, 15 Jul 2007 15:53:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Candelas",
"Philip",
""
],
[
"de la Ossa",
"Xenia",
""
],
[
"He",
"Yang-Hui",
""
],
[
"Szendroi",
"Balazs",
""
]
] |
0706.3135 | Helen Matskevich | S.M. Gerasyuta and E.E. Matskevich | Excited $(70,L^+)$ baryon resonances in the relativistic quark model | latex, 23 pages, 3 figures | Phys.Rev.D76:116004,2007 | 10.1103/PhysRevD.76.116004 | null | hep-ph | null | The masses of positive parity $(70,0^+)$ and $(70,2^+)$ nonstrange and
strange baryons are calculated in the relativistic quark model. The
relativistic three-quark equations of the $(70,L^+)$ multiplets are found in
the framework of the dispersion relation technique. The approximate solutions
of these equations using the method based on the extraction of leading
singularities of the amplitude are obtained. The calculated mass values of the
$(70,L^+)$ multiplets are in good agreement with the experimental ones.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:19:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gerasyuta",
"S. M.",
""
],
[
"Matskevich",
"E. E.",
""
]
] |
0706.3136 | Namiko Mitarai | Michael Bretz, Russell Zaretzki, Stuart B. Field, Namiko Mitarai, and
Franco Nori | Broad distribution of stick-slip events in Slowly Sheared Granular
Media: Table-top production of a Gutenberg-Richter-like distribution | 10 pages, 3 figures | Europhys. Lett. vol. 74, pp. 1116-1122 (2006) | 10.1209/epl/i2006-10048-2 | null | cond-mat.stat-mech cond-mat.soft | null | We monitor the stick-slip displacements of a very slowly driven moveable
perforated top plate which interacts via shearing with a packing of identical
glass beads confined in a tray. When driven at a constant stress rate, the
distributions of large event displacements and energies triggered by the
stick-slip instabilities exhibit power law responses reminiscent of the
Gutenberg-Richter law for earthquakes. Small events are quasi-size independent,
signaling crossover from single-bead transport to collective behavior.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:24:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bretz",
"Michael",
""
],
[
"Zaretzki",
"Russell",
""
],
[
"Field",
"Stuart B.",
""
],
[
"Mitarai",
"Namiko",
""
],
[
"Nori",
"Franco",
""
]
] |
0706.3137 | Emma Jin | Emma Y. Jin and Christian M. Reidys | Asymptotic Enumeration of RNA Structures with Pseudoknots | 22 pages, 7 figures | null | null | null | q-bio.BM math.CO | null | In this paper we present the asymptotic enumeration of RNA structures with
pseudoknots. We develop a general framework for the computation of exponential
growth rate and the sub exponential factors for $k$-noncrossing RNA structures.
Our results are based on the generating function for the number of
$k$-noncrossing RNA pseudoknot structures, ${\sf S}_k(n)$, derived in
\cite{Reidys:07pseu}, where $k-1$ denotes the maximal size of sets of mutually
intersecting bonds. We prove a functional equation for the generating function
$\sum_{n\ge 0}{\sf S}_k(n)z^n$ and obtain for $k=2$ and $k=3$ the analytic
continuation and singular expansions, respectively. It is implicit in our
results that for arbitrary $k$ singular expansions exist and via transfer
theorems of analytic combinatorics we obtain asymptotic expression for the
coefficients. We explicitly derive the asymptotic expressions for 2- and
3-noncrossing RNA structures. Our main result is the derivation of the formula
${\sf S}_3(n) \sim \frac{10.4724\cdot 4!}{n(n-1)...(n-4)}
(\frac{5+\sqrt{21}}{2})^n$.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:31:34 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Jin",
"Emma Y.",
""
],
[
"Reidys",
"Christian M.",
""
]
] |
0706.3138 | Heinrich Leutwyler | H. Leutwyler | Insights and puzzles in light quark physics | Contribution to the proceedings of the Rencontres de Moriond on QCD
and Hadronic Interactions, La Thuile, Italy, March 2007; added references,
minor changes in the text | null | null | null | hep-ph | null | Recent work in light flavour hadron physics is reviewed. In particular, I
discuss the significance of the progress achieved with light dynamical quarks
on the lattice for the effective low energy theory of QCD. Also, I draw
attention to some puzzling results from NA48 and KTeV concerning the scalar
form factor relevant for Kmu3 decay -- taken at face value, these indicate
physics beyond the Standard Model.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:25:50 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 10:27:01 GMT"
}
] | 2007-07-10T00:00:00 | [
[
"Leutwyler",
"H.",
""
]
] |
0706.3139 | Markus Diehl | M. Diehl and W. Kugler | Exclusive Meson Production at NLO | 4 pages. Talk given at DIS 2007. v2: corrections in plots, modified
conclusions | null | null | DESY 07-093 | hep-ph | null | We report on numerical studies of the NLO corrections to exclusive meson
electroproduction, both in collider and fixed-target kinematics. Corrections
are found to be huge at small xB and sizeable at intermediate or large xB.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:34:51 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 11:37:01 GMT"
}
] | 2007-08-08T00:00:00 | [
[
"Diehl",
"M.",
""
],
[
"Kugler",
"W.",
""
]
] |
0706.3140 | Christophe Chevalier | C. Chevalier, A. Lindner and E. Clement | Saffman-Taylor instability in a non-Brownian suspension: finger
selection and destabilization | 4 pages, 4 figures, submitted to PRL | null | null | null | cond-mat.soft | null | We study the Saffman-Taylor instability in a non-Brownian suspension by
injection of air. We find that flow structuration in the Hele-Shaw cell can be
described by an effective viscosity depending on the volume fraction. When this
viscosity is used to define the control parameter of the instability, the
classical finger selection for Newtonian fluids is recovered. However, this
picture breaks down when the cell thickness is decreased below approximatively
10 grain sizes. The discrete nature of the grains plays also a determinant role
in the the early destabilization of the fingers observed. The grains produce a
perturbation at the interface proportional to the grain size and can thus be
considered as a "controlled noise". The finite amplitude instability mechanism
proposed earlier by Bensimon et al. allows to link this perturbation to the
actual values of the destabilization threshold.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:37:05 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Chevalier",
"C.",
""
],
[
"Lindner",
"A.",
""
],
[
"Clement",
"E.",
""
]
] |
0706.3141 | Delfim F. M. Torres | Rui A. C. Ferreira, Delfim F. M. Torres | Higher-Order Calculus of Variations on Time Scales | Corrected minor typos | Mathematical Control Theory and Finance, Springer, 2008, pp.
149--160 | 10.1007/978-3-540-69532-5_9 | null | math.OC math.CA math.FA | null | We prove a version of the Euler-Lagrange equations for certain problems of
the calculus of variations on time scales with higher-order delta derivatives.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:43:31 GMT"
},
{
"version": "v2",
"created": "Sun, 30 Sep 2007 23:23:19 GMT"
}
] | 2009-08-13T00:00:00 | [
[
"Ferreira",
"Rui A. C.",
""
],
[
"Torres",
"Delfim F. M.",
""
]
] |
0706.3142 | Marie-Line Chabanol | Marie-Line Chabanol | Three-point correlations for quantum star graphs | 10 pages, 2 figures | J. Phys. A: Math. Theor. 40 (2007) 13535-13544. | 10.1088/1751-8113/40/45/004 | null | math-ph math.MP | null | We compute the three point correlation function for the eigenvalues of the
Laplacian on quantum star graphs in the limit where the number of edges tends
to infinity. This extends a work by Berkolaiko and Keating, where they get the
2-point correlation function and show that it follows neither Poisson, nor
random matrix statistics. It makes use of the trace formula and combinatorial
analysis.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:49:17 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Nov 2007 15:52:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chabanol",
"Marie-Line",
""
]
] |
0706.3143 | Tobias Stauber | T. Stauber and J. Ranninger | First Order Superfluid to Bose Metal Transition in Systems with Resonant
Pairing | 5 pages, 3 figures | Phys. Rev. Lett. 99, 045301 (2007) | 10.1103/PhysRevLett.99.045301 | null | cond-mat.supr-con cond-mat.str-el | null | Systems showing resonant superfluidity, driven by an exchange coupling of
strength $g$ between uncorrelated pairs of itinerant fermions and tightly bound
ones, undergo a first order phase transition as $g$ increases beyond some
critical value $g_c$. The superfluid phase for $g \leq g_c$ is characterized by
a gap in the fermionic single particle spectrum and an acoustic sound-wave like
collective mode of the bosonic resonating fermion pairs inside this gap. For
$g>g_c$ this state gives way to a phase uncorrelated bosonic liquid with a
$q^2$ spectrum.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:01:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stauber",
"T.",
""
],
[
"Ranninger",
"J.",
""
]
] |
0706.3144 | Davor Palle | Davor Palle (IRB, Zagreb, Croatia) | Comment on the paper "Weyssenhoff fluid dynamics in a 1+3 covariant
approach" (arXiv:0706.2367) | 2 pages, 5 references | null | null | null | astro-ph gr-qc | null | Few comments are given to clarify some issues of Weyssenhoff fluid in the
Einstein-Cartan gravity.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:21:22 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Palle",
"Davor",
"",
"IRB, Zagreb, Croatia"
]
] |
0706.3145 | Yasuhiro Shimizu | Junji Hisano, Yasuhiro Shimizu | Revisiting Signature of Minimal Gauge Mediation | 20 pages, 16 figures | Phys.Lett.B655:269-279,2007 | 10.1016/j.physletb.2007.08.087 | null | hep-ph | null | We revisit phenomenology of the minimal gauge-mediated model. This model is
motivated from the SUSY CP and flavor problems. A specific feature of this
model is that \tan\beta is naturally large, since the B term in the Higgs
potential is zero at the messenger scale. This leads to significant SUSY
contributions to various low-energy observables. We evaluate the anomalous
magnetic moment of the muon and the branching ratio of \bar{B}\to X_s\gamma
taking account of recent theoretical and experimental developments. We find
that the current experimental data prefer a low messenger scale (\sim 100 TeV)
and gluino mass around 1 TeV. We also calculate the branching ratios of
\bar{B}\to X_s l^+l^-, B_s\to \mu^+\mu^-, and B^-\to \tau^- \bar{\nu}, and show
that these observables are strongly correlated with each other in this model.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:21:48 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Aug 2007 10:19:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hisano",
"Junji",
""
],
[
"Shimizu",
"Yasuhiro",
""
]
] |
0706.3146 | Hao Hu | Hao Hu, Steven Myers, Vittoria Colizza, Alessandro Vespignani | WiFi Epidemiology: Can Your Neighbors' Router Make Yours Sick? | 22 pages, 1 table, 4 figures | Proceedings of the National Academy of Sciences, vol. 106, no. 5,
1318-1323 (2009) | 10.1073/pnas.0811973106 | null | cs.CR physics.soc-ph | null | In densely populated urban areas WiFi routers form a tightly interconnected
proximity network that can be exploited as a substrate for the spreading of
malware able to launch massive fraudulent attack and affect entire urban areas
WiFi networks. In this paper we consider several scenarios for the deployment
of malware that spreads solely over the wireless channel of major urban areas
in the US. We develop an epidemiological model that takes into consideration
prevalent security flaws on these routers. The spread of such a contagion is
simulated on real-world data for geo-referenced wireless routers. We uncover a
major weakness of WiFi networks in that most of the simulated scenarios show
tens of thousands of routers infected in as little time as two weeks, with the
majority of the infections occurring in the first 24 to 48 hours. We indicate
possible containment and prevention measure to limit the eventual harm of such
an attack.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:36:21 GMT"
}
] | 2009-02-11T00:00:00 | [
[
"Hu",
"Hao",
""
],
[
"Myers",
"Steven",
""
],
[
"Colizza",
"Vittoria",
""
],
[
"Vespignani",
"Alessandro",
""
]
] |
0706.3147 | W. A. Sabra | Jan B. Gutowski and Wafic A. Sabra | Half-Supersymmetric Solutions in Five-Dimensional Supergravity | 56 pages, reference added, typos corrected | JHEP 0712:025,2007; Erratum-ibid.1004:042,2010 | 10.1088/1126-6708/2007/12/025 10.1007/JHEP04(2010)042 | null | hep-th | null | We present a systematic classification of half-supersymmetric solutions of
gauged N=2, D=5 supergravity coupled to an arbitrary number of abelian vector
multiplets for which at least one of the Killing spinors generate a time-like
Killing vector.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:37:40 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Dec 2007 15:08:44 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Gutowski",
"Jan B.",
""
],
[
"Sabra",
"Wafic A.",
""
]
] |
0706.3148 | Pierre Muller | P. Muller | Finite size effects on surface excess quantities: application to crystal
growth and surface melting of epitaxial layers | 20 pages 6 figures | Russian Journal of Physical Chemistry Vol 77 Suppl 1 (2003)
S135-142 | null | null | cond-mat.mtrl-sci | null | From a macroscopic point of view phase transitions as surface melting or two
dimensional (2D) towards three dimensional (3D) growth mode (Stranski-Krastanov
transition) can be described in terms of Gibbs excess quantity duly amended by
size effects (since usual Gibbs excess quantities are only well defined for
semi-infinite systems). The aim of this study is to consider such amended
quantities to describe surface melting and Stranski-Krastanov transition of
epitaxial layers. the so-introduced size effects allows us to predict the
equilibrium thickness of the wetting layer of the Stranski-Krastanov growth
mode and to describe and classify two different melting cases: the incomplete
melting relayed by a first order transition and the continuous premelting
relayed by continuous overheating
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:42:46 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Muller",
"P.",
""
]
] |
0706.3149 | Marceau Limousin | Marceau Limousin, Jesper Sommer-Larsen, Priyamvada Natarajan, Bo
Milvang-Jensen | Probing the truncation of galaxy dark matter halos in high density
environments from hydrodynamical N-body simulations | Accepted for publication in ApJ | Astrophys.J.696:1771-1779,2009 | 10.1088/0004-637X/696/2/1771 | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analyze high resolution, N-body hydrodynamical simulations of fiducial
galaxy clusters to probe tidal stripping of the dark matter subhalos. These
simulations include a prescription for star formation allowing us to track the
fate of the stellar component as well. We investigate the effect of tidal
stripping on cluster galaxies hosted in these dark matter subhalos as a
function of cluster-centric radius. To quantify the extent of the dark matter
halos of cluster galaxies, we introduce the half mass radius r_half as a
diagnostic, and study its evolution with projected cluster-centric distance R
as a function of redshift. We find a well defined trend for (r_half,R): the
closer the galaxies are to the center of the cluster, the smaller the half mass
radius. Interestingly, this trend is inferred in all redshift frames examined
in this work ranging from z=0 to z=0.7. At z=0, galaxy halos in the central
regions of clusters are found to be highly truncated, with the most compact
half mass radius of 10 kpc. We also find that r_half depends on luminosity and
we present scaling relations of r_half with galaxy luminosity. The
corresponding total mass of the cluster galaxies is also found to increase with
projected cluster-centric distance and luminosity, but with more scatter than
the (r_half,R) trend. Comparing the distribution of stellar mass to total mass
for cluster galaxies, we find that the dark matter component is preferentially
stripped, whereas the stellar component remains protected by the halo and is
much less affected by tidal forces. We compare these results with galaxy-galaxy
lensing probes of r_half and find qualitative agreement. (Abridged)
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:49:44 GMT"
},
{
"version": "v2",
"created": "Fri, 23 Nov 2007 14:47:36 GMT"
},
{
"version": "v3",
"created": "Wed, 10 Dec 2008 12:54:32 GMT"
},
{
"version": "v4",
"created": "Tue, 3 Mar 2009 13:26:09 GMT"
}
] | 2009-05-01T00:00:00 | [
[
"Limousin",
"Marceau",
""
],
[
"Sommer-Larsen",
"Jesper",
""
],
[
"Natarajan",
"Priyamvada",
""
],
[
"Milvang-Jensen",
"Bo",
""
]
] |
0706.3150 | Alexander Finch | ALEPH collaboration | Measurement of the Cross Section for open b-Quark Production in
Two-Photon Interactions at LEP | 15 pages, 8 figures. Submitted to JHEP | JHEP 0709:102,2007 | 10.1088/1126-6708/2007/09/102 | null | hep-ex | null | Inclusive beauty-quark production in two-photon collisions has been measured
at LEP using an integrated luminosity of 698 pb-1 collected by the ALEPH
detector with sqrt(s) between 130 and 209 GeV. The b quarks were identified
using lifetime information. The cross section is found to be sigma(e+ e- --> e+
e- b \bar{b} X) = (5.4 +/- 0.8 (stat) +/- 0.8 (syst)) pb which is consistent
with Next-to-Leading Order QCD.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 13:50:45 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"ALEPH collaboration",
"",
""
]
] |
0706.3151 | Alberto Mariotti | A.Amariti, L.Girardello, A.Mariotti | Meta-stable A_n quiver gauge theories | Minor corrections, reference added, published in JHEP | JHEP 0710:017,2007 | 10.1088/1126-6708/2007/10/017 | null | hep-th | null | We study metastable dynamical breaking of supersymmetry in A_n quiver gauge
theories. We present a general analysis and criteria for the perturbative
existence of metastable vacua in quivers of any length. Different mechanisms of
gauge mediation can be realized.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:21:35 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 17:03:39 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Amariti",
"A.",
""
],
[
"Girardello",
"L.",
""
],
[
"Mariotti",
"A.",
""
]
] |
0706.3152 | Delfim F. M. Torres | Rui A. C. Ferreira, Delfim F. M. Torres | Remarks on the calculus of variations on time scales | null | Int. J. Ecol. Econ. Stat., Vol. 9, Nr. F07, 2007, pp. 65--73. | null | null | math.OC math.CA | null | The calculus of variations is a classical subject which has gain throughout
the last three hundred years a level of rigor and elegance that only time can
give. In this note we show that, contrary to the classical field, available
formulations and results on the recent calculus of variations on time scales
are still at the heuristic level.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:02:04 GMT"
}
] | 2007-09-30T00:00:00 | [
[
"Ferreira",
"Rui A. C.",
""
],
[
"Torres",
"Delfim F. M.",
""
]
] |
0706.3153 | Hans Weber | H. J. Weber | Connections between Romanovski and other polynomials | 17 pages, no figures, to appear in Central European J. Math. (2007) | null | null | null | math.CA | null | A connection between Romanovski polynomials and those polynomials that solve
the one-dimensional Schr\"odinger equation with the trigonometric Rosen-Morse
and hyperbolic Scarf potential is established. The map is constructed by
reworking the Rodrigues formula in an elementary and natural way. The
generating function is summed in closed form from which recursion relations and
addition theorems follow. Relations to some classical polynomials are also
given.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:03:10 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Weber",
"H. J.",
""
]
] |
0706.3154 | Halton Arp | H. Arp, D. Carosati | M31 and Local Group QSO's | 18 pages,9 figures | null | null | null | astro-ph | null | Previous analyses have shown companion galaxies aligned along the minor axis
of M31. The alignment includes some galaxies of higher redshift than
conventionally accepted for Local Group members. Here we look at the
distribution of all high redshift objects listed in a 10 x 10 deg. area around
M31. We find not only galaxies of higher redshift but also quasars along the
minor axis of this brightest Local Group galaxy, Some are an unusual class of
low z, quasar-galaxy.
Previously observers had noted radio sources aligned along the minor axis of
M31. The ejection directions of quasars from active galaxy nuclei is also along
the minor axis within a cone of about 20 deg. opening angle. It is shown here
that the quasar-like and higher redshift objects associated with M31 are
relatively concentrated along this axis.
M33 also falls closely along the minor axis of M31 and the famous 3C48 and
similar redshift galaxy/quasars are seen along a line coming from this Local
Group companion of M31. What appears to be dusty nebulosity has also been shown
to exist along this extended line in the sky.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 12:08:29 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Arp",
"H.",
""
],
[
"Carosati",
"D.",
""
]
] |
0706.3155 | Kingman Cheung | Kingman Cheung, Wai-Yee Keung, Tzu-Chiang Yuan | Collider Phenomenology of Unparticle Physics | 37 pages. 16 figures, some additional comments and references | Phys.Rev.D76:055003,2007 | 10.1103/PhysRevD.76.055003 | null | hep-ph hep-th | null | Low energy phenomenology of the unparticle physics associated with an exact
scale invariant sector possessing a non-trivial infrared fixed point at a
higher energy scale is explored for both electron-positron and hadronic
colliders. Feynman rules for a spin 0, 1 or 2 unparticle coupled to a variety
of standard model gauge invariant operators that are relevant to many low
energy processes involving either real emissions of unparticles or their
virtual propagator effects are presented. Missing energy and/or recoil mass
distributions of the unparticle in the associated production of unparticle
together with a photon or $Z$ boson at LEP2 and ILC as well as in $Z$ decay
into an unparticle plus a fermion-antifermion pair are studied. Monojet
production at hadronic collisions is explored. The complex phase in the
unparticle propagator that can give rise to interesting interference effects
between an unparticle exchange diagram and the standard model amplitudes are
studied in details for the Drell-Yan process as well as muon pair and diphoton
production in electron-positron annihilation. These energy and/or recoil mass
distributions (with the exception in hadron colliders) and interference effects
are found sensitively depending not only on the scale dimension but also on the
spin of the unparticle. For the spin-2 unparticle, its physical effects is
found to resemble that of a tower of Kaluza-Klein gravitons, which strongly
indicates that the underlying unparticle physics may have root in a higher
dimensional theory. A connection between unparticle physics and theories of
large extra dimension is speculated. Experimental constraints on the unparticle
scale are deduced from the LEP2 data on mono-photon production and from the
4-fermion contact interactions.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:04:35 GMT"
},
{
"version": "v2",
"created": "Sun, 1 Jul 2007 08:42:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cheung",
"Kingman",
""
],
[
"Keung",
"Wai-Yee",
""
],
[
"Yuan",
"Tzu-Chiang",
""
]
] |
0706.3156 | M. Angeles Serrano | M. Angeles Serrano and Paolo De Los Rios | Interfaces and the edge percolation map of random directed networks | 20 pages, 4 figures | Physical Review E 76, 056121 (2007) | 10.1103/PhysRevE.76.056121 | null | cond-mat.dis-nn physics.soc-ph | null | The traditional node percolation map of directed networks is reanalyzed in
terms of edges. In the percolated phase, edges can mainly organize into five
distinct giant connected components, interfaces bridging the communication of
nodes in the strongly connected component and those in the in- and
out-components. Formal equations for the relative sizes in number of edges of
these giant structures are derived for arbitrary joint degree distributions in
the presence of local and two-point correlations. The uncorrelated null model
is fully solved analytically and compared against simulations, finding an
excellent agreement between the theoretical predictions and the edge
percolation map of synthetically generated networks with exponential or
scale-free in-degree distribution and exponential out-degree distribution.
Interfaces, and their internal organization giving place from "hairy ball"
percolation landscapes to bottleneck straits, could bring new light to the
discussion of how structure is interwoven with functionality, in particular in
flow networks.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:54:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Serrano",
"M. Angeles",
""
],
[
"Rios",
"Paolo De Los",
""
]
] |
0706.3157 | Lorenzo Magnea | Matteo Cacciari, Mrinal Dasgupta, Lorenzo Magnea and Gavin Salam | Power corrections for jets at hadron colliders | 5 pages, 1 figure. Talk presented by L. Magnea at DIS 2007, Munich,
Germany, April 16-20 2007 | null | null | null | hep-ph | null | We discuss non-perturbative QCD corrections to jet distributions in hadron
collisions, focussing on hadronisation and underlying event contributions.
Using soft gluon resummation and Monte-Carlo modelling we show that
hadronisation dominates at small values of the jet radius R, behaving as 1/R,
while underlying event corrections grow with the jet area. This provides a
handle to disentangle them and parametrize them in terms of measurable QCD
parameters, which might enjoy a degree of universality.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:19:18 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Cacciari",
"Matteo",
""
],
[
"Dasgupta",
"Mrinal",
""
],
[
"Magnea",
"Lorenzo",
""
],
[
"Salam",
"Gavin",
""
]
] |
0706.3158 | Mathias Zessin | Mathias Zessin | On contact tops and integrable tops | 20 pages | null | null | null | math.DG math.GT | null | In this paper, we introduce a geometric structure called top, which is a
trivialized bundle of plane pencils over a Riemannian 3-manifold, defined as
the set of kernels of a circle of 1-forms (e.g. of contact and integrable
forms) with particular properties with respect to the metric. We classify the
manifolds which admit tops and we describe the associated metrics.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:19:26 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Zessin",
"Mathias",
""
]
] |
0706.3159 | Pierre Deransart | Pierre Deransart (INRIA Rocquencourt), Mireille Ducass\'e (IRISA),
G\'erard Ferrand (LIFO) | Une s\'emantique observationnelle du mod\`ele des bo\^ites pour la
r\'esolution de programmes logiques (version \'etendue) | Project of research report used to produce the paper presented at
JFPC 2007 | null | null | null | cs.PL cs.SE | null | This report specifies an observational semantics and gives an original
presentation of the Byrd's box model. The approach accounts for the semantics
of Prolog tracers independently of a particular implementation. Traces are, in
general, considered as rather obscure and difficult to use. The proposed formal
presentation of a trace constitutes a simple and pedagogical approach for
teaching Prolog or for implementing Prolog tracers. It constitutes a form of
declarative specification for the tracers. Our approach highlights qualities of
the box model which made its success, but also its drawbacks and limits. As a
matter of fact, the presented semantics is only one example to illustrate
general problems relating to tracers and observing processes. Observing
processes know, from observed processes, only their traces. The issue is then
to be able to reconstitute by the sole analysis of the trace the main part of
the observed process, and if possible, without any loss of information.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:20:30 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 14:03:05 GMT"
}
] | 2007-06-25T00:00:00 | [
[
"Deransart",
"Pierre",
"",
"INRIA Rocquencourt"
],
[
"Ducassé",
"Mireille",
"",
"IRISA"
],
[
"Ferrand",
"Gérard",
"",
"LIFO"
]
] |
0706.3160 | Rembert Duine | R.A. Duine | Spin pumping by a field-driven domain wall | 4 pages, 1 figure v2: some typos corrected v3: published version | Phys. Rev. B 77, 014409 (2008) | 10.1103/PhysRevB.77.014409 | null | cond-mat.mes-hall | null | We calculate the charge current in a metallic ferromagnet to first order in
the time derivative of the magnetization direction. Irrespective of the
microscopic details, the result can be expressed in terms of the conductivities
of the majority and minority electrons and the non-adiabatic spin transfer
torque parameter $\beta$. The general expression is evaluated for the specific
case of a field-driven domain wall and for that case depends strongly on the
ratio of $\beta$ and the Gilbert damping constant. These results may provide an
experimental method to determine this ratio, which plays a crucial role for
current-driven domain-wall motion.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:29:34 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 15:12:08 GMT"
},
{
"version": "v3",
"created": "Wed, 9 Jan 2008 10:45:26 GMT"
}
] | 2008-01-09T00:00:00 | [
[
"Duine",
"R. A.",
""
]
] |
0706.3161 | Anatoly Patrick E | A.E. Patrick | Euler Walk on a Cayley Tree | null | Journal of Statistical Physics, vol. 127, No. 3, May 2007, pp.
629-653 | 10.1007/s10955-007-9281-5 | E17-2006-122 | cond-mat.stat-mech math.PR | null | We show that the Euler walk on a Cayley tree exhibits two regimes (dynamic
phases): a condensed phase and a low-density phase. In the condensed phase the
self-organized area grows as a compact domain. In the low-density phase the
proportion of self-organized (visited) nodes decreases rapidly from one
generation of the tree to the next. We describe in detail returns of the Euler
walk to the root and growth of the self-organized domain in the condensed
phase. We also investigate the critical behaviour of the Euler walk at the
point separating the two regimes.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:33:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Patrick",
"A. E.",
""
]
] |
0706.3162 | Kouji Yano | Kouji Yano and Yuko Yano | Remarks on the density of the law of the occupation time for Bessel
bridges and stable excursions | null | null | null | null | math.PR | null | Smoothness and asymptotic behaviors are studied for the densities of the law
of the occupation time on the positive line for Bessel bridges and the
normalized excursion of strictly stable processes. The key role is played by
these properties for functions defined by Riemann--Liouville fractional
integrals.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:36:13 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Yano",
"Kouji",
""
],
[
"Yano",
"Yuko",
""
]
] |
0706.3163 | David M. Bradley | David M. Bradley | Verhulst's logistic curve | 5 pages AMSLaTeX, 2 figures | The College Mathematics Journal, Vol. 32, No. 2, March 2001, pp.
94--98. [MR 1833354] (2002c:26002) | null | null | math.HO math.CA | null | We observe that the elementary logistic differential equation dP/dt=(1-P/M)kP
may be solved by first changing the variable to R=(M-P)/P. This reduces the
logistic differential equation to the simple linear differential equation
dR/dt=-kR, which can be solved without using the customary but slightly more
elaborate methods applied to the original logistic DE. The resulting solution
in terms of R can be converted by simple algebra to the familiar sigmoid
expression involving P. A biological argument is given for introducing logistic
growth via the simpler DE for R. It is also shown that the sigmoid P may be
written in terms of the hyperbolic tangent by a simple translation that is also
motivated by a biological argument.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:54:19 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Bradley",
"David M.",
""
]
] |
0706.3164 | Maxim Zabzine | Francesco Bonechi and Maxim Zabzine | Poisson sigma model on the sphere | 38 pages | Commun.Math.Phys.285:1033-1063,2009 | 10.1007/s00220-008-0615-1 | null | hep-th math.SG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We evaluate the path integral of the Poisson sigma model on sphere and study
the correlators of quantum observables. We argue that for the path integral to
be well-defined the corresponding
Poisson structure should be unimodular. The construction of the finite
dimensional BV theory is presented and we argue that it is responsible for the
leading semiclassical contribution. For a (twisted) generalized Kahler manifold
we discuss the gauge fixed action for the Poisson sigma model. Using the
localization we prove that for the holomorphic Poisson structure the
semiclassical result for the correlators is indeed the full quantum result.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:39:37 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jul 2007 14:56:37 GMT"
},
{
"version": "v3",
"created": "Tue, 13 Jan 2009 07:44:15 GMT"
}
] | 2009-01-13T00:00:00 | [
[
"Bonechi",
"Francesco",
""
],
[
"Zabzine",
"Maxim",
""
]
] |
0706.3165 | Hichem Geryville | Hichem Geryville (LIESP), Abdelaziz Bouras (LIESP), Yacine Ouzrout
(LIESP), Nikolaos Sapidis | A solution for actors' viewpoints representation with collaborative
product development | ISBN: 2-287-48363-9 | Research in Interactive Design (2007) 39-40 | 10.1007/978-2-287-48370-7 | null | cs.HC | null | As product complexity and marketing competition increase, a collaborative
product development is necessary for companies which develop high quality
products in short lead-times. To support product actors from different fields,
disciplines, and locations, wishing to exchange and share information, the
representation of the actors' viewpoints is the underlying requirement of the
collaborative product development. The actors' viewpoints approach was designed
to provide an organisational framework following the actors' perspectives in
the collaboration, and their relationships, could be explicitly gathered and
formatted. The approach acknowledges the inevitability of multiple integration
of product information as different views, promotes gathering of actors'
interests, and encourages retrieved adequate information while providing
support for integration through PLM and/or SCM collaboration. In this paper, a
solution for neutral viewpoints representation is proposed. The product,
process, and organisation information models are seriatim discussed. A series
of issues referring to the viewpoints representation are discussed in detail.
Based on XML standard, taking cyclone vessel as an example, an application case
of part of product information modelling is stated.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:40:25 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Geryville",
"Hichem",
"",
"LIESP"
],
[
"Bouras",
"Abdelaziz",
"",
"LIESP"
],
[
"Ouzrout",
"Yacine",
"",
"LIESP"
],
[
"Sapidis",
"Nikolaos",
""
]
] |
0706.3166 | Victor Krym Dr. | V.R. Krym, N.N. Petrov | The Equations of Motion of a Charged Particle in the Five-Dimensional
Model of the General Relativity Theory with the Four-Dimensional Nonholonomic
Velocity Space | 14 pages, 4 figures | Vestn.St.Peterburg.Univ.1:62-70,2007 | null | null | math.DG gr-qc math.MG math.OC physics.class-ph | null | We consider the four-dimensional nonholonomic distribution defined by the
4-potential of the electromagnetic field on the manifold. This distribution has
a metric tensor with the Lorentzian signature $(+,-,-,-)$, therefore, the
causal structure appears as in the general relativity theory. By means of the
Pontryagin's maximum principle we proved that the equations of the horizontal
geodesics for this distribution are the same as the equations of motion of a
charged particle in the general relativity theory. This is a Kaluza -- Klein
problem of classical and quantum physics solved by methods of sub-Lorentzian
geometry. We study the geodesics sphere which appears in a constant magnetic
field and its singular points. Sufficiently long geodesics are not optimal
solutions of the variational problem and define the nonholonomic wavefront.
This wavefront is limited by a convex elliptic cone. We also study variational
principle approach to the problem. The Euler -- Lagrange equations are the same
as those obtained by the Pontryagin's maximum principle if the restriction of
the metric tensor on the distribution is the same.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:49:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Krym",
"V. R.",
""
],
[
"Petrov",
"N. N.",
""
]
] |
0706.3167 | Daniel Boyanovsky | D. Boyanovsky | Production of a sterile species via active-sterile mixing: an exactly
solvable model | To appear in Phys. Rev. D | Phys.Rev.D76:103514,2007 | 10.1103/PhysRevD.76.103514 | null | hep-ph | null | The production of a sterile species via active-sterile mixing in a thermal
medium is studied in an exactly solvable model. The \emph{exact} time evolution
of the sterile distribution function is determined by the dispersion relations
and damping rates $\Gamma_{1,2}$ for the quasiparticle modes. These depend on
$\wtg = \Gamma_{aa}/2\Delta E$, with $\Gamma_{aa}$ the interaction rate of the
active species in absence of mixing and $\Delta E$ the oscillation frequency in
the medium without damping. $\wtg \ll1,\wtg \gg 1$ describe the weak and strong
damping limits respectively. For $\wtg\ll1$, $\Gamma_1 = \Gamma_{aa}\cos^2\tm ;
\Gamma_{2}=\Gamma_{aa}\sin^2\tm$ where $\tm$ is the mixing angle in the medium
and the sterile distribution function \emph{does not} obey a simple rate
equation. For $\wtg \gg 1$, $\Gamma_1= \Gamma_{aa}$ and $\Gamma_2 = \Gamma_{aa}
\sin^22\tm/4\wtg^2$, is the sterile production rate. In this regime sterile
production is suppressed and the oscillation frequency \emph{vanishes} at an
MSW resonance, with a breakdown of adiabaticity. These are consequences of
quantum Zeno suppression. For active neutrinos with standard model interactions
the strong damping limit is \emph{only} available near an MSW resonance
\emph{if} $\sin\theta \lesssim \alpha_w$ with $\theta$ the vacuum mixing angle.
The full set of quantum kinetic equations for sterile production for arbitrary
$\wtg$ are obtained from the quantum master equation. Cosmological resonant
sterile neutrino production is quantum Zeno suppressed relieving potential
uncertainties associated with the QCD phase transition.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 14:58:50 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 18:58:16 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Boyanovsky",
"D.",
""
]
] |
0706.3168 | Elena G. Ferreiro | L. Cunqueiro, E. G. Ferreiro and C. Pajares | Fluctuations and the clustering of color sources | 2 pages, 2 figures. Contributed to Workshop on Heavy Ion Collisions
at the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun
2007 | null | null | null | hep-ph | null | We present our results on multiplicity and $p_T$ fluctuations at LHC energies
in the framework of the clustering of color sources. In this approach,
elementary color sources -strings- overlap forming clusters, so the number of
effective sources is modified. We find that the fluctuations are proportional
to the number of those clusters.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:04:41 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Cunqueiro",
"L.",
""
],
[
"Ferreiro",
"E. G.",
""
],
[
"Pajares",
"C.",
""
]
] |
0706.3169 | Matteo Siccardi | S. Arnone, G. Di Segni, M. Siccardi and K. Yoshida | N=1* model superpotential revisited (IR behaviour of N=4 limit) | 31 pages | Int.J.Mod.Phys.A22:5089-5115,2007 | 10.1142/S0217751X07037998 | null | hep-th | null | The one-loop contribution to the superpotential, in particular the
Veneziano-Yankielowicz potential in N=1 supersymmetric Yang-Mills model is
discussed from an elementary field theory method and the matrix model point of
view. Both approaches are based on the Renormalization Group variation of the
superconformal N=4 supersymmetric Yang-Mills model.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:04:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Arnone",
"S.",
""
],
[
"Di Segni",
"G.",
""
],
[
"Siccardi",
"M.",
""
],
[
"Yoshida",
"K.",
""
]
] |
0706.3170 | Keigo Takeuchi | Keigo Takeuchi, Toshiyuki Tanaka, and Toru Yano | Asymptotic Analysis of General Multiuser Detectors in MIMO DS-CDMA
Channels | Submitted to IEEE Journal on Selected Areas in Communications | null | 10.1109/JSAC.2008.080407 | null | cs.IT math.IT | null | We analyze a MIMO DS-CDMA channel with a general multiuser detector including
a nonlinear multiuser detector, using the replica method. In the many-user,
limit the MIMO DS-CDMA channel with the multiuser detector is decoupled into a
bank of single-user SIMO Gaussian channels if a spatial spreading scheme is
employed. On the other hand, it is decoupled into a bank of single-user MIMO
Gaussian channels if a spatial spreading scheme is not employed. The spectral
efficiency of the MIMO DS-CDMA channel with the spatial spreading scheme is
comparable with that of the MIMO DS-CDMA channel using an optimal space-time
block code without the spatial spreading scheme. In the case of the QPSK data
modulation scheme the spectral efficiency of the MIMO DS-CDMA channel with the
MMSE detector shows {\it waterfall} behavior and is very close to the
corresponding sum capacity when the system load is just below the transition
point of the {\it waterfall} behavior. Our result implies that the performance
of a multiuser detector taking the data modulation scheme into consideration
can be far superior to that of linear multiuser detectors.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:05:28 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Takeuchi",
"Keigo",
""
],
[
"Tanaka",
"Toshiyuki",
""
],
[
"Yano",
"Toru",
""
]
] |
0706.3171 | Anatoly Serebrov | A.P. Serebrov, V.E. Varlamov, A.G. Kharitonov, A.K. Fomin, Yu.N.
Pokotilovski, P. Geltenbort, I.A. Krasnoschekova, M.S. Lasakov, R.R.
Tal'daev, A.V. Vassiljev, O.M. Zherebtsov | Comment to the article "Possible Systematic Effects in Fomblin Coated
Storage Cell Neutron Lifetime Measurements", Steve K. Lamoreaux [1] | 3 pages | null | null | null | nucl-ex | null | The author of article discusses the possible systematic effects in our
experiment using reference and picture from allegedly our publication. First of
all this publication does not exist. The assumption of author about the
probability of lower energy upscattering is in a rough contradiction (300
times) with our experimental limit which is extremely lower, about 6x10-9 per
neutron collision. The second assumption of author concerning quasi-stable
orbits of UCN with higher energy due to specular neutron reflection from trap
wall is also in a rough contradiction with our experimental data clear
demonstrated in our previous articles as well in the last very detailed article
recently presented in the arXiv.
We are very surprised that author discusses well known questions studied in
our experiment in details.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:10:07 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Serebrov",
"A. P.",
""
],
[
"Varlamov",
"V. E.",
""
],
[
"Kharitonov",
"A. G.",
""
],
[
"Fomin",
"A. K.",
""
],
[
"Pokotilovski",
"Yu. N.",
""
],
[
"Geltenbort",
"P.",
""
],
[
"Krasnoschekova",
"I. A.",
""
],
[
"Lasakov",
"M. S.",
""
],
[
"Tal'daev",
"R. R.",
""
],
[
"Vassiljev",
"A. V.",
""
],
[
"Zherebtsov",
"O. M.",
""
]
] |
0706.3172 | Denis Sheka | Denis D. Sheka, Yuri Gaididei and Franz G. Mertens | Switching of the vortex polarity in a magnetic nanodisk by a DC current | REVTeX, 4 pages, 3 figures | Appl. Phys. Lett. 91 (2007) 082509 | 10.1063/1.2775036 | null | cond-mat.str-el | null | We study the dynamics of a vortex state nanodisk due to a dc spin current,
perpendicular to the disk plane. The irreversible switching of the vortex
polarity takes place above some threshold current. The detailed description of
these processes is obtained by spin-lattice simulations.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:11:10 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Jun 2007 22:29:30 GMT"
}
] | 2007-08-26T00:00:00 | [
[
"Sheka",
"Denis D.",
""
],
[
"Gaididei",
"Yuri",
""
],
[
"Mertens",
"Franz G.",
""
]
] |
0706.3173 | Mariano Cadoni | M. Cadoni, R. De Leo, G. Gaeta | Sine-Gordon solitons, auxiliary fields, and singular limit of a double
pendulums chain | 18 pages, 2 figures | J. Phys. A40 (2007) 12917 | 10.1088/1751-8113/40/43/006 | null | math-ph math.MP nlin.PS | null | We consider the continuum version of an elastic chain supporting topological
and non-topological degrees of freedom; this generalizes a model for the
dynamics of DNA recently proposed and investigated by ourselves. In a certain
limit, the non-topological degrees of freedom are frozen, and the model reduces
to the sine-Gordon equations and thus supports well-known topological soliton
solutions. We consider a (singular) perturbative expansion around this limit
and study in particular how the non-topological field assume the role of an
auxiliary field. This provides a more general framework for the slaving of this
degree of freedom on the topological one, already observed elsewhere in the
context of the mentioned DNA model; in this framework one expects such
phenomenon to arise in a quite large class of field-theoretical models.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:23:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cadoni",
"M.",
""
],
[
"De Leo",
"R.",
""
],
[
"Gaeta",
"G.",
""
]
] |
0706.3174 | D. J. Saikia | Ananda Hota (1,2,3), D.J. Saikia (1), Judith A. Irwin (4) ((1) NCRA,
TIFR, Pune, India, (2) JAP, IISc, Bangalore, India, (3) ASIAA, Taipei,
Taiwan, (4) Queen's University, Kingston, Canada) | NGC4438 and its environment at radio wavelengths | 16 pages, 14 figures, 5 tables, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12114.x | null | astro-ph | null | We present multi-frequency, radio-continuum and HI observations of NGC4438,
the highly-disturbed, active galaxy in the Virgo cluster, with the VLA and the
GMRT. High-resolution observations with the VLA at 4860 and 8460 MHz show the
presence of an inverted-spectrum radio nucleus located between the highly
asymmetric lobes of radio emission. This demonstrates that these lobes arise
due to an AGN rather than a compact nuclear starburst. The low-frequency radio
continuum observations made with the GMRT detect the extended emission on the
western side of the galaxy whose spectral index is flatter at higher
frequencies and suggests that it is a mixture of thermal and non-thermal
emission.
The HI observations show an elongated structure which is displaced by ~4.1
kpc on the western side of NGC4438 and has a size of ~9.8 kpc and a mass of
1.8*10^8 M_sun. The velocity field suggests systematic rotation. We also detect
HI emission from the disk of the galaxy with a mass of 1.2*10^8 M_sun. We
detect a faint HI tail towards the north of NGC4438 close to a stellar tail
seen in deep optical observations. This HI tail has a total extent of ~50 kpc
and a mass of 1.4*10^8 M_sun if it is at the distance of NGC4438. The velocity
of the HI tail is ~-10 km/s similar to that of HI emission from IC 3355, but
the possibility that the tail could be foreground Galactic emission cannot be
ruled out. We discuss the different structures in the light of different
models.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:29:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hota",
"Ananda",
""
],
[
"Saikia",
"D. J.",
""
],
[
"Irwin",
"Judith A.",
""
]
] |
0706.3175 | Corsin Battaglia | C. Battaglia, H. Cercellier, C. Monney, L. Despont, M.G. Garnier and
P. Aebi | Unveiling new systematics in the self-assembly of atomic chains on
Si(111) | Proceedings of the International Conference on Nano Science and
Technology ICN+T 2007, to be published in Journal of Physics: Conference
Series | J. Phys.: Conf. Ser. 100, 052078 (2008) | 10.1088/1742-6596/100/5/052078 | null | cond-mat.other | null | Self-assembled arrays of atomic chains on Si(111) represent a fascinating
family of nanostructures with quasi-one-dimensional electronic properties.
These surface reconstructions are stabilized by a variety of adsorbates ranging
from alkali and alkaline earth metals to noble and rare earth metals. Combining
the complementary strength of dynamical low-energy electron diffraction,
scanning tunneling microscopy and angle-resolved photoemission spectroscopy, we
recently showed that besides monovalent and divalent adsorbates, trivalent
adsorbates are also able to stabilize silicon honeycomb chains. Consequently
silicon honeycomb chains emerge as a most stable, universal building block
shared by many atomic chain structures. We here present the systematics behind
the self-assembly mechanism of these chain systems and relate the valence state
of the adsorbate to the accessible symmetries of the chains.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:29:19 GMT"
}
] | 2008-09-05T00:00:00 | [
[
"Battaglia",
"C.",
""
],
[
"Cercellier",
"H.",
""
],
[
"Monney",
"C.",
""
],
[
"Despont",
"L.",
""
],
[
"Garnier",
"M. G.",
""
],
[
"Aebi",
"P.",
""
]
] |
0706.3176 | Patricio Gaete | Patricio Gaete and Iv\'an Schmidt | Properties of noncommutative axionic electrodynamics | 4 pages. To appear in PRD | Phys.Rev.D76:027702,2007 | 10.1103/PhysRevD.76.027702 | USM-TH-212 | hep-th | null | Using the gauge-invariant but path-dependent variables formalism, we compute
the static quantum potential for noncommutative axionic electrodynamics, and
find a radically different result than the corresponding commutative case. We
explicitly show that the static potential profile is analogous to that
encountered in both non-Abelian axionic electrodynamics and in Yang-Mills
theory with spontaneous symmetry breaking of scale symmetry.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:32:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gaete",
"Patricio",
""
],
[
"Schmidt",
"Iván",
""
]
] |
0706.3177 | Laurent Perrinet | Laurent Perrinet (INT, INCM) | Role of homeostasis in learning sparse representations | null | Neural Computation, Massachusetts Institute of Technology Press
(MIT Press), 2010, 22 (7), pp.1812-36 | 10.1162/neco.2010.05-08-795 | null | q-bio.NC | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Neurons in the input layer of primary visual cortex in primates develop
edge-like receptive fields. One approach to understanding the emergence of this
response is to state that neural activity has to efficiently represent sensory
data with respect to the statistics of natural scenes. Furthermore, it is
believed that such an efficient coding is achieved using a competition across
neurons so as to generate a sparse representation, that is, where a relatively
small number of neurons are simultaneously active. Indeed, different models of
sparse coding, coupled with Hebbian learning and homeostasis, have been
proposed that successfully match the observed emergent response. However, the
specific role of homeostasis in learning such sparse representations is still
largely unknown. By quantitatively assessing the efficiency of the neural
representation during learning, we derive a cooperative homeostasis mechanism
that optimally tunes the competition between neurons within the sparse coding
algorithm. We apply this homeostasis while learning small patches taken from
natural images and compare its efficiency with state-of-the-art algorithms.
Results show that while different sparse coding algorithms give similar coding
results, the homeostasis provides an optimal balance for the representation of
natural images within the population of neurons. Competition in sparse coding
is optimized when it is fair. By contributing to optimizing statistical
competition across neurons, homeostasis is crucial in providing a more
efficient solution to the emergence of independent components.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:32:54 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 12:44:09 GMT"
},
{
"version": "v3",
"created": "Wed, 6 Feb 2008 08:10:52 GMT"
},
{
"version": "v4",
"created": "Wed, 19 Mar 2008 08:00:43 GMT"
},
{
"version": "v5",
"created": "Fri, 19 Sep 2008 19:26:23 GMT"
},
{
"version": "v6",
"created": "Fri, 25 Jun 2010 13:33:29 GMT"
},
{
"version": "v7",
"created": "Thu, 8 Dec 2016 12:52:51 GMT"
}
] | 2016-12-09T00:00:00 | [
[
"Perrinet",
"Laurent",
"",
"INT, INCM"
]
] |
0706.3178 | Orr Shalit | Orr Shalit | Representing a product system representation as a contractive semigroup
and applications to regular isometric dilations | 15 pages | Canadian Mathematical Bulletin, Vol. 53, No. 3 (2010) 550-563 | null | null | math.OA | null | In this paper we propose a new technical tool for analyzing representations
of Hilbert $C^*$-product systems. Using this tool, we give a new proof that
every doubly commuting representation over $\mathbb{N}^k$ has a regular
isometric dilation, and we also prove sufficient conditions for the existence
of a regular isometric dilation of representations over more general
subsemigroups of $\mathbb{R}_+^k$.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:37:46 GMT"
}
] | 2011-05-13T00:00:00 | [
[
"Shalit",
"Orr",
""
]
] |
0706.3179 | Jacco Vink | Jacco Vink (Utrecht University) | Supernova remnants with magnetars: clues to magnetar formation | Accepted by Advances in Space Research (Cospar 2006, Beijing, Session
E1.4) | Adv.SpaceRes.41:503-511,2008 | 10.1016/j.asr.2007.06.042 | null | astro-ph | null | I discuss the lack of observational evidence that magnetars are formed as
rapidly rotating neutron stars. Supernova remnants containing magnetars do not
show the excess of kinetic energy expected for such a formation scenario, nor
is there any evidence for a relic pulsar wind nebula. However, it could be that
magnetars are formed with somewhat slower rotation periods, or that not all
excess rotational energy was used to boost the explosion energy, for example as
a result of gravitational radiation. Another observational tests for the rapid
initial period hypothesis is to look for statistical evidence that about 1% of
the observed supernovae have an additional 1E40-1E44 erg/s excess energy during
the first year, caused by the spin down luminosity of a magnetar. An
alternative scenario for the high magnetic fields of magnetars is the fossil
field hypothesis, in which the magnetic field is inherited from the progenitor
star. Direct observational tests for this hypothesis are harder to formulate,
unless the neutron star formed in the SN1987A explosion emerges as a slowly
rotating magnetar. Finally, I point out the possible connection between the
jets in Cas A and its X-ray point source: the jets in Cas A may indicate that
the explosion was accompanied by an X-ray flash, probably powered by a rapidly
rotating compact object. However, the point source in Cas A does not seem to be
a rapidly rotating neutron star, suggesting that the neutron star has slowed
down considerably in 330 yr, requiring a magnetar-like field.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:48:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Vink",
"Jacco",
"",
"Utrecht University"
]
] |
0706.3180 | Wen Bin Song | Wenbin Song, Xueshang Feng | The Emerging Features of Bipolar Magnetic Regions during Solar Minima | 5 figures, 1 table, accepted by ApJ | null | 10.1086/521141 | null | astro-ph | null | Solar magnetic synoptic charts obtained by NSO/Kitt Peak and SOHO/MDI are
analyzed for studying the appearance of bipolar magnetic regions (BMRs) during
solar minima. As a result, we find the emergence of long-lived BMRs has three
typical features. (1) BMRs' emerging rates of the new cycles increase about 3
times faster than those of the old cycles decrease. (2) Two consecutive solar
cycles have an overlapping period of near 10 Carrington rotations. During this
very short overlapping time interval, BMRs of two cycles tend to concentrate in
the same longitudes. (3) About 53% BMRs distribute with a longitudinal distance
of 1/8 solar rotation. Such phenomenon suggests a longitudinal mode of m=8
existing during solar minima.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:51:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Song",
"Wenbin",
""
],
[
"Feng",
"Xueshang",
""
]
] |
0706.3181 | Renato Portugal | Amanda C. Oliveira, Renato Portugal, and Raul Donangelo | Simulation of the Single- and Double-Slit Experiments with Quantum
Walkers | 7 pages, 8 figures | null | null | null | quant-ph | null | We employ the broken-link model to create a barrier with slits in a
two-dimensional lattice. The diffraction and interference patterns of the
probability distribution of quantum walkers passing through the slits are
analyzed. Simulations were performed using the main types of coins, and display
diffraction and interference patterns that depend on the choice of coins.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:53:40 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Oliveira",
"Amanda C.",
""
],
[
"Portugal",
"Renato",
""
],
[
"Donangelo",
"Raul",
""
]
] |
0706.3182 | Fronefield Crawford | F. Crawford, C. L. Tiffany | Flux Densities and Radio Polarization Characteristics of Two Vela-like
Pulsars | 8 pages, including 4 figures and 3 tables. Accepted for publication
in AJ | Astron.J.134:1231-1236,2007 | 10.1086/521020 | null | astro-ph | null | We report on dual-frequency radio polarimetry observations of two young,
energetic pulsars, PSRs J0940-5428 and J1301-6305. These were among the first
Vela-like pulsars discovered in the Parkes Multibeam survey. We conducted
observations of these pulsars with the Australia Telescope Compact Array (ATCA)
at center frequencies of 1384 and 2496 MHz using pulsar gating while preserving
full Stokes parameters. After correcting for bandwidth depolarization, we have
measured polarization characteristics, flux densities, and rotation measures
for these pulsars. The spectral indices derived from the ATCA data are shallow
but still consistent with values seen for pulsars of this type. The rotation
measures for both pulsars are consistent with those reported recently using
data from the Parkes telescope, and both pulsars have highly linearly polarized
pulse profiles at both 1384 and 2496 MHz. Our results support a previously
noted correlation between high degree of linear polarization, shallow spectral
index, and large spin-down luminosity.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 15:59:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Crawford",
"F.",
""
],
[
"Tiffany",
"C. L.",
""
]
] |
0706.3183 | Vlatko Vedral | V. Vedral | Entanglement Production in Non-Equilibrium Thermodynamics | 6 pages, no figures | null | null | null | quant-ph | null | We define and analyse the concept of entanglement production during the
evolution of a general quantum mechanical dissipative system. While it is
important to minimise entropy production in order to achieve thermodynamical
efficiency, maximising the rate of change of entanglement is important in
quantum information processing. Quantitative relations are obtained between
entropy and entanglement productions, under specific assumptions detailed in
the text. We apply these to the processes of dephasing and decay of
correlations between two initially entangled qubits. Both the Master equation
treatment as well as the higher Hilbert space analysis are presented. Our
formalism is very general and contains as special cases many reported
individual instance of entanglement dynamics, such as, for example, the
recently discovered notion of the sudden death of entanglement.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:00:24 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Vedral",
"V.",
""
]
] |
0706.3184 | Sigbjorn Hervik | S Hervik, R J van den Hoogen, W C Lim and A A Coley | Late-time behaviour of the tilted Bianchi type VI$_{-1/9}$ models | 13 pages, 1 figure, v2: typos fixed, minor changes, matches published
version | Class.Quant.Grav.25:015002,2008 | 10.1088/0264-9381/25/1/015002 | null | gr-qc astro-ph math-ph math.MP | null | We study tilted perfect fluid cosmological models with a constant equation of
state parameter in spatially homogeneous models of Bianchi type VI$_{-1/9}$
using dynamical systems methods and numerical simulations. We study models with
and without vorticity, with an emphasis on their future asymptotic evolution.
We show that for models with vorticity there exists, in a small region of
parameter space, a closed curve acting as the attractor.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:08:53 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 10:57:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hervik",
"S",
""
],
[
"Hoogen",
"R J van den",
""
],
[
"Lim",
"W C",
""
],
[
"Coley",
"A A",
""
]
] |
0706.3185 | Alexander Zyuzin | A. A. Zyuzin and A. Yu. Zyuzin | Resistivity effects in surface superconductivity of thin films in strong
magnetic fields | 4 pages, 3 figures, submitted to JETP Letters: Pisma v ZhETF vol. 86,
is. 1 | null | null | null | cond-mat.supr-con | null | Phase slips creation in the thin film in perpendicular magnetic filed with
edge superconductivity is studied. These centers are due to thermal activation
of the order parameter below superconducting temperature transition leading to
the suppression of the superconductivity. The corresponding resistance is
calculated. The Alsamazov- Larkin correction to the conductivity above the
critical magnetic field destroying the surface superconductivity is studied.
Such structures could be applied as a new system for the study of the phase
slip phenomenon in one- dimensional superconducting wires.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:23:32 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Zyuzin",
"A. A.",
""
],
[
"Zyuzin",
"A. Yu.",
""
]
] |
0706.3186 | Christian Roos | M. Chwalla, K. Kim, T. Monz, P. schindler, M. Riebe, C. F. Roos, R.
Blatt | Precision spectroscopy with two correlated atoms | null | Appl. Phys. B 89, 483-488 (2007) | 10.1007/s00340-007-2867-4 | null | quant-ph physics.atom-ph | null | We discuss techniques that allow for long coherence times in laser
spectroscopy experiments with two trapped ions. We show that for this purpose
not only entangled ions prepared in decoherence-free subspaces can be used but
also a pair of ions that are not entangled but subject to the same kind of
phase noise. We apply this technique to a measurement of the electric
quadrupole moment of the 3d D5/2 state of 40Ca+ and to a measurement of the
linewidth of an ultrastable laser exciting a pair of 40Ca+ ions.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:31:05 GMT"
},
{
"version": "v2",
"created": "Mon, 19 Nov 2007 07:21:44 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Chwalla",
"M.",
""
],
[
"Kim",
"K.",
""
],
[
"Monz",
"T.",
""
],
[
"schindler",
"P.",
""
],
[
"Riebe",
"M.",
""
],
[
"Roos",
"C. F.",
""
],
[
"Blatt",
"R.",
""
]
] |
0706.3187 | Dimitris Christodoulou | Dimitris M. Christodoulou, Ioannis Contopoulos, and Demosthenes
Kazanas | Simulations of the Poynting--Robertson Cosmic Battery in Resistive
Accretion Disks | 27 pages, 55 figures | null | 10.1086/524699 | null | astro-ph | null | We describe the results of numerical "2.5--dimensional" MHD simulations of an
initially unmagnetized disk model orbiting a central point--mass and responding
to the continual generation of poloidal magnetic field due to a secular source
that emulates the Poynting--Robertson (PR) drag on electrons in the vicinity of
a luminous stellar or compact accreting object. The fluid in the disk and in
the surrounding hotter atmosphere has finite electrical conductivity and allows
for the magnetic field to diffuse freely out of the areas where it is
generated, while at the same time, the differential rotation of the disk twists
the poloidal field and quickly induces a substantial toroidal--field component.
The secular PR term has dual purpose in these simulations as the source of the
magnetic field and the trigger of a magnetorotational instability (MRI) in the
disk. The MRI is especially mild and does not destroy the disk because a small
amount of resistivity dampens the instability efficiently. In simulations with
moderate resistivities (diffusion timescales up to $\sim$16 local dynamical
times) and after $\sim$100 orbits, the MRI has managed to transfer outward
substantial amounts of angular momentum and the inner edge of the disk, along
with azimuthal magnetic flux, has flowed toward the central point--mass where a
new, magnetized, nuclear disk has formed. The toroidal field in this nuclear
disk is amplified by differential rotation and it cannot be contained; when it
approaches equipartition, it unwinds vertically and produces episodic jet--like
outflows. The poloidal field in the inner region cannot diffuse back out if the
characteristic diffusion time is of the order of or larger than the dynamical
time; it continues to grow linearly in time undisturbed and without saturation,
as the outer sections of many poloidal loops are being drawn radially outward.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 18:32:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Christodoulou",
"Dimitris M.",
""
],
[
"Contopoulos",
"Ioannis",
""
],
[
"Kazanas",
"Demosthenes",
""
]
] |
0706.3188 | Vladimir Vovk | Glenn Shafer and Vladimir Vovk | A tutorial on conformal prediction | 58 pages, 9 figures | Journal of Machine Learning Research 9 (2008) 371-421.
http://www.jmlr.org/papers/v9/shafer08a.html | null | null | cs.LG stat.ML | null | Conformal prediction uses past experience to determine precise levels of
confidence in new predictions. Given an error probability $\epsilon$, together
with a method that makes a prediction $\hat{y}$ of a label $y$, it produces a
set of labels, typically containing $\hat{y}$, that also contains $y$ with
probability $1-\epsilon$. Conformal prediction can be applied to any method for
producing $\hat{y}$: a nearest-neighbor method, a support-vector machine, ridge
regression, etc.
Conformal prediction is designed for an on-line setting in which labels are
predicted successively, each one being revealed before the next is predicted.
The most novel and valuable feature of conformal prediction is that if the
successive examples are sampled independently from the same distribution, then
the successive predictions will be right $1-\epsilon$ of the time, even though
they are based on an accumulating dataset rather than on independent datasets.
In addition to the model under which successive examples are sampled
independently, other on-line compression models can also use conformal
prediction. The widely used Gaussian linear model is one of these.
This tutorial presents a self-contained account of the theory of conformal
prediction and works through several numerical examples. A more comprehensive
treatment of the topic is provided in "Algorithmic Learning in a Random World",
by Vladimir Vovk, Alex Gammerman, and Glenn Shafer (Springer, 2005).
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:40:06 GMT"
}
] | 2019-04-23T00:00:00 | [
[
"Shafer",
"Glenn",
""
],
[
"Vovk",
"Vladimir",
""
]
] |
0706.3189 | Tunc Erkmen | Metin Arik, Tunc Erkmen | Exponentially Expanding Radiation Dominated and Dust Dominated Universes
in Brans-Dicke Theory | 3 pages, 1 figure | null | null | null | gr-qc | null | The Brans-Dicke Theory of Gravity is one of the most promising alternatives
to the Einstein's Theory of General Relativity. We have examined an action term
with wrong signs for both the kinetic and mass terms for the scalar field and
have found solutions for both the scale factor of the universe and the
Brans-Dicke scalar field which vary exponentially in time.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:47:23 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Arik",
"Metin",
""
],
[
"Erkmen",
"Tunc",
""
]
] |
0706.3190 | Pierre Muller | P.Muller, R.Kern | Equilibrium nano-shape changes induced by epitaxial stress (generalised
Wulf-Kaishew theorem) | 57 pages, 9 figures | Surface Science 457 (2000) 229 | 10.1016/S0039-6028(00)00371-X | null | cond-mat.mtrl-sci | null | A generalised Wulf-Kaishew theorem is given describing the equilibrium shape
(ES) of an isolated 3D crystal A deposited coherently onto a lattice mismatched
planar substrate. For this purpose a free polyhedral crystal is formed then
homogeneously strained to be accommodated onto the lattice mismatched
substrate. During its elastic inhomogeneous relaxation the epitaxial contact
remains coherent so that the 3D crystal drags the atoms of the contact area and
produces a strain field in the substrate. The ES of the deposit is obtained by
minimising at constant volume the total energy (bulk and surface energies)
taking into account the bulk elastic relaxation. Our main results are: (1)
Epitaxial strain acts against wetting (adhesion) so that globally it leads to a
thickening of the ES. (2) Owing to strain the ES changes with size. More
precisely the various facets extension changes, some facets decreasing, some
others increasing. (3) Each dislocation entrance, necessary for relaxing
plastically too large crystals abruptly modifies the ES and thus the different
facets extension in a jerky way. (4) In all cases the usual self-similarity
with size is lost when misfit is considered. We illustrate these points in case
of box shaped and truncated pyramidal crystals. Some experimental evidences are
discussed.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:18:18 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Muller",
"P.",
""
],
[
"Kern",
"R.",
""
]
] |
0706.3191 | Gorbovskoy Evgeny | V.Lipunov (1,2,3), E.Gorbovskoy (1,2,3) ((1) Sternberg Astronomical
Institute, (2) Dep. of Physics of Moscow State University, (3) Moscow Union
'Optic') | Spinar Paradigm and Gamma Ray Bursts Central Engine | 17 pages, 16-figures, MNRAS in print | null | null | null | astro-ph | null | A spinar is a quasi-equilibrium collapsing object whose equilibrium is
maintained by the balance of centrifugal and gravitational forces and whose
evolution is determined by its magnetic field. The spinar quasi equilibrium
model recently discussed as the course for extralong X-ray plateu in GRB
(Lipunov & Gorbovskoy, 2007). We propose a simple non stationary
three-parameter collapse model with the determining role of rotation and
magnetic field in this paper. The input parameters of the theory are the mass,
angular momentum, and magnetic field of the collapsar. The model includes
approximate description of the following effects: centrifugal force,
relativistic effects of the Kerr metrics, pressure of nuclear matter,
dissipation of angular momentum due to magnetic field, decrease of the dipole
magnetic moment due to compression and general-relativity effects (the black
hole has no hare), neutrino cooling, time dilatation, and gravitational
redshift. The model describes the temporal behavior of the central engine and
demonstrates the qualitative variety of the types of such behavior in nature.
We apply our approach to explain the observed features of gamma-ray bursts of
all types. In particular, the model allows the phenomena of precursors, x-ray
and optical bursts, and the appearance of a plateau on time scales of several
thousand seconds to be unified.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:54:06 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Jun 2007 12:11:27 GMT"
},
{
"version": "v3",
"created": "Thu, 1 Nov 2007 13:03:38 GMT"
},
{
"version": "v4",
"created": "Fri, 2 Nov 2007 12:00:07 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Lipunov",
"V.",
""
],
[
"Gorbovskoy",
"E.",
""
]
] |
0706.3192 | Igor Krasovsky | A. Its, I. Krasovsky | Hankel determinant and orthogonal polynomials for the Gaussian weight
with a jump | 34 pages, 7 figures | null | null | null | math.FA math-ph math.MP | null | We obtain asymptotics in n for the n-dimensional Hankel determinant whose
symbol is the Gaussian multiplied by a step-like function. We use
Riemann-Hilbert analysis of the related system of orthogonal polynomials to
obtain our results.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 16:59:05 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 19:57:29 GMT"
},
{
"version": "v3",
"created": "Sun, 11 May 2008 11:55:44 GMT"
}
] | 2008-05-11T00:00:00 | [
[
"Its",
"A.",
""
],
[
"Krasovsky",
"I.",
""
]
] |
0706.3193 | Gregory Moore | Emanuel Diaconescu and Gregory W. Moore | Crossing the Wall: Branes vs. Bundles | 23pp. latex, one figure | null | null | null | hep-th | null | We test a recently proposed wall-crossing formula for the change of the
Hilbert space of BPS states in d=4,N=2 theories. We study decays of D4D2D0
systems into pairs of D4D2D0 systems and we show how the wall-crossing formula
reproduces results of Goettsche and Yoshioka on wall-crossing behavior of the
moduli of slope-stable holomorphic bundles over holomorphic surfaces. Our
comparison shows very clearly that the moduli space of the D4D2D0 system on a
rigid surface in a Calabi-Yau is not the same as the moduli space of torsion
free sheaves, even when worldhseet instantons are neglected. Moreover, we argue
that the physical formula should make some new mathematical predictions for a
future theory of the moduli of stable objects in the derived category.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:05:32 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Diaconescu",
"Emanuel",
""
],
[
"Moore",
"Gregory W.",
""
]
] |
0706.3194 | Andrea De Luca | A. Manzali, A. De Luca, P.A. Caraveo | Phase resolved spectroscopy of the Vela pulsar with XMM-Newton | 27 pages, 9 figures. Accepted for publication in ApJ | null | 10.1086/521387 | null | astro-ph | null | The ~10^4 y old Vela Pulsar represents the bridge between the young Crab-like
and the middle-aged rotation powered pulsars. Its multiwavelength behaviour is
due to the superposition of different spectral components. We take advantage of
the unprecedented harvest of photons collected by XMM-Newton to assess the Vela
Pulsar spectral shape and to study the pulsar spectrum as a function of its
rotational phase. As for the middle-aged pulsars Geminga, PSR B0656+14 and PSR
B1055-52 (the "Three Musketeers"), the phase-integrated spectrum of Vela is
well described by a three-component model, consisting of two blackbodies
(T_bb1=(1.06+/-0.03)x10^6 K, R_bb1=5.1+/-0.3 km, T_bb2=(2.16+/-0.06)x10^6 K,
R_bb2=0.73+/-0.08 km) plus a power-law (gamma=2.2+/-0.3). The relative
contributions of the three components are seen to vary as a function of the
pulsar rotational phase. The two blackbodies have a shallow 7-9% modulation.
The cooler blackbody, possibly related to the bulk of the neutron star surface,
has a complex modulation, with two peaks per period, separated by ~0.35 in
phase, the radio pulse occurring exactly in between. The hotter blackbody,
possibly originating from a hot polar region, has a nearly sinusoidal
modulation, with a single, broad maximum aligned with the second peak of the
cooler blackbody, trailing the radio pulse by ~0.15 in phase. The non thermal
component, magnetospheric in origin, is present only during 20% of the pulsar
phase and appears to be opposite to the radio pulse. XMM-Newton phase-resolved
spectroscopy unveils the link between the thermally emitting surface of the
neutron star and its charge-filled magnetosphere, probing emission geometry as
a function of the pulsar rotation. This is a fundamental piece of information
for future 3-dimensional modeling of the pulsar magnetosphere.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:06:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Manzali",
"A.",
""
],
[
"De Luca",
"A.",
""
],
[
"Caraveo",
"P. A.",
""
]
] |
0706.3195 | George Bass Ph.D. | George E. Bass | Genetic Transferability of Anomalous Irradiation Alterations of
Antibiotic Activity | 17 pages, 3 figures | null | null | null | q-bio.BM | null | It previously has been discovered that visible light irradiation of
crystalline substrates can lead to enhancement of subsequent enzymatic reaction
rates as sharply peaked oscillatory functions of irradiation time. The
particular activating irradiation times can vary with source of a given enzyme
and thus, presumably, its molecular structure. The experiments reported here
demonstrate that the potential for this anomalous enzyme reaction rate
enhancement can be transferred from one bacterial species to another coincident
with transfer of the genetic determinant for the relevant enzyme. In
particular, the effect of crystal-irradiated chloramphenicol on growth of
bacterial strains in which a transferable R-factor DNA plasmid coding for
chloramphenicol resistance was or was not present (S. panama R+, E. coli R+,
and E. coli R-) was determined. Chloramphenicol samples irradiated 10, 35 and
60 sec produced increased growth rates (diminished inhibition) for the
resistant S. panama and E. coli strains, while having no such effect on growth
rate of the sensitive E. coli strain. Consistent with past findings,
chloramphenicol samples irradiated 5, 30 and 55 sec produced decreased growth
rates (increased inhibition) for all three strains.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:24:15 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Bass",
"George E.",
""
]
] |
0706.3196 | Roberto Aloisio | R. Aloisio and F. Tortorici | Super Heavy Dark Matter and UHECR Anisotropy at Low Energy | 18 pages, 14 eps figures, version accepted for publication in
Astroparticle Physics | Astropart.Phys.29:307-316,2008 | 10.1016/j.astropartphys.2008.02.005 | null | astro-ph | null | Super Heavy quasi-stable particles are naturally produced in the early
universe and could represent a substantial fraction of the Dark Matter: the
so-called Super Heavy Dark Matter (SHDM). The decay of SHDM represents also a
possible source of Ultra High Energy Cosmic Rays (UHECR), with a reliably
calculated spectrum of the particles produced in the decay $(\propto
E^{-1.9})$. The SHDM model for the production of UHECR can explain
quantitatively only the excess of UHE events observed by AGASA. In the case of
an observed spectrum not showing the AGASA excess the SHDM model can provide
only a {\it subdominant} contribution to the UHECR flux. We discuss here the
basic features of SHDM for the production of a {\it subdominant} UHECR flux, we
refer our study to the possible signatures of the model at the Auger
observatory discussing in particular the expected chemical composition and
anisotropy.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:31:21 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Feb 2008 17:36:06 GMT"
}
] | 2013-06-11T00:00:00 | [
[
"Aloisio",
"R.",
""
],
[
"Tortorici",
"F.",
""
]
] |
0706.3197 | D. J. Saikia | Ananda Hota (1,2,3), D.J. Saikia (1) ((1) NCRA, TIFR, Pune, India, (2)
JAP, IISc, Bangalore, India, (3) ASIAA, Taipei, Taiwan) | An HI study of three long-tailed irregular galaxies in the cluster
Abell1367 | 19 pages, 19 figures, 3 tables, accepted for publication in the
Bulletin of the Astronomical Society of India | null | null | null | astro-ph | null | We present the results on the distribution and kinematics of H$\sc{i}$ gas
with higher sensitivity and in one case of higher spectral resolution as well
than reported earlier, of three irregular galaxies CGCG 097073, 097079 and
097087 (UGC 06697) in the cluster Abell 1367. These galaxies are known to
exhibit long (50$-$75 kpc) tails of radio continuum and optical emission lines
(H$\alpha$) pointing away from the cluster centre and arcs of starformation on
the opposite sides of the tails. These features as well as the H{\sc i}
properties, with two of the galaxies (CGCG 097073 and 097079) exhibiting
sharper gradients in H{\sc i} intensity on the side of the tails, are
consistent with the H{\sc i} gas being affected by the ram pressure of the
intracluster medium. However the H{\sc i} emission in all the three galaxies
extends to much smaller distances than the radio-continuum and H$\alpha$ tails,
and are possibly still bound to the parent galaxies. Approximately 20$-$30 per
cent of the H{\sc i} mass is seen to accumulate on the downstream side due to
the effects of ram pressure.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:06:21 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Hota",
"Ananda",
""
],
[
"Saikia",
"D. J.",
""
]
] |
0706.3198 | Andr\'e da Silva Ricardo Rocha | George E. A. Matsas and Andr\'e R. R. da Silva | Overspinning a nearly extreme charged black hole via a quantum tunneling
process | Submitted to Physical Review Letters, 4 pages, 3 figures | Phys.Rev.Lett.99:181301,2007 | 10.1103/PhysRevLett.99.181301 | null | gr-qc hep-th | null | We examine a nearly extreme macroscopic Reissner-Nordstrom black hole in the
context of semi-classical gravity. The absorption rate associated with the
quantum tunneling process of scalar particles whereby this black hole can
acquire enough angular momentum to violate the weak cosmic censorship
conjecture is shown to be nonzero.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:42:48 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 19:23:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Matsas",
"George E. A.",
""
],
[
"da Silva",
"André R. R.",
""
]
] |
0706.3199 | Sever Amit | Albion Lawrence and Amit Sever | Scattering of twist fields from D-branes and orientifolds | 34 pages, 8 figures. v2 -- references added | JHEP0709:094,2007 | 10.1088/1126-6708/2007/09/094 | BRX TH-584, KITP-06-126 | hep-th | null | We compute the two-point function for Z_N orbifold twist fields on the disk
and RP2. We apply this to a computation of the O(g_s) correction to the Kahler
potential for (the symmetric combination of) blow-up modes in type I string
theory on T^6/Z_3. This is related by supersymmetry to the one-loop field
dependent correction to the Fayet-Iliopoulos D-term for the anomalous U(1)
factor. We find this correction to be non-vanishing away from the orbifold
point.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:06:09 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 22:49:29 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lawrence",
"Albion",
""
],
[
"Sever",
"Amit",
""
]
] |
0706.3200 | Miguel de Val-Borro | M. de Val-Borro, P. Artymowicz, G. D'Angelo, A. Peplinski | Vortex generation in protoplanetary disks with an embedded giant planet | 14 pages, 15 figures, accepted for publication in A&A | Astron.Astrophys. 471 (2007) 1043-1055 | 10.1051/0004-6361:20077169 | null | astro-ph | null | Vortices in protoplanetary disks can capture solid particles and form
planetary cores within shorter timescales than those involved in the standard
core-accretion model. We investigate vortex generation in thin unmagnetized
protoplanetary disks with an embedded giant planet with planet to star mass
ratio $10^{-4}$ and $10^{-3}$. Two-dimensional hydrodynamical simulations of a
protoplanetary disk with a planet are performed using two different numerical
methods. The results of the non-linear simulations are compared with a
time-resolved modal analysis of the azimuthally averaged surface density
profiles using linear perturbation theory. Finite-difference methods
implemented in polar coordinates generate vortices moving along the gap created
by Neptune-mass to Jupiter-mass planets. The modal analysis shows that unstable
modes are generated with growth rate of order $0.3 \Omega_K$ for azimuthal
numbers m=4,5,6, where $\Omega_K$ is the local Keplerian frequency.
Shock-capturing Cartesian-grid codes do not generate very much vorticity around
a giant planet in a standard protoplanetary disk. Modal calculations confirm
that the obtained radial profiles of density are less susceptible to the growth
of linear modes on timescales of several hundreds of orbital periods.
Navier-Stokes viscosity of the order $\nu=10^{-5}$ (in units of $a^2 \Omega_p$)
is found to have a stabilizing effect and prevents the formation of vortices.
This result holds at high resolution runs and using different types of boundary
conditions. Giant protoplanets of Neptune-mass to Jupiter-mass can excite the
Rossby wave instability and generate vortices in thin disks. The presence of
vortices in protoplanetary disks has implications for planet formation, orbital
migration, and angular momentum transport in disks.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:00:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"de Val-Borro",
"M.",
""
],
[
"Artymowicz",
"P.",
""
],
[
"D'Angelo",
"G.",
""
],
[
"Peplinski",
"A.",
""
]
] |
0706.3201 | Timothy Clifton | Timothy Clifton, Stephen Shenker and Navin Sivanandam | Volume Weighted Measures of Eternal Inflation in the Bousso-Polchinski
Landscape | 35 pages, 8 figures | JHEP0709:034,2007 | 10.1088/1126-6708/2007/09/034 | null | hep-th astro-ph gr-qc | null | We consider the cosmological dynamics associated with volume weighted
measures of eternal inflation, in the Bousso-Polchinski model of the string
theory landscape. We find that this measure predicts that observers are most
likely to find themselves in low energy vacua with one flux considerably larger
than the rest. Furthermore, it allows for a satisfactory anthropic explanation
of the cosmological constant problem by producing a smooth, and approximately
constant, distribution of potentially observable values of Lambda. The low
energy vacua selected by this measure are often short lived. If we require
anthropically acceptable vacua to have a minimum life-time of 10 billion years,
then for reasonable parameters a typical observer should expect their vacuum to
have a life-time of approximately 12 billion years. This prediction is model
dependent, but may point toward a solution to the coincidence problem of
cosmology.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:45:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Clifton",
"Timothy",
""
],
[
"Shenker",
"Stephen",
""
],
[
"Sivanandam",
"Navin",
""
]
] |
0706.3202 | John Parejko | John K. Parejko, Anca Constantin, Michael S. Vogeley (Drexel
University), and Fiona Hoyle (Widener University) | Source Matching in the SDSS and RASS: Which Galaxies are Really X-ray
Sources? | 10 pages, 10 figures, submitted to The Astronomical Journal on 19
June 2007 | Astron.J.135:10-19,2008 | 10.1088/0004-6256/135/1/10 | null | astro-ph | null | The current view of galaxy formation holds that all massive galaxies harbor a
massive black hole at their center, but that these black holes are not always
in an actively accreting phase. X-ray emission is often used to identify
accreting sources, but for galaxies that are not harboring quasars
(low-luminosity active galaxies), the X-ray flux may be weak, or obscured by
dust. To aid in the understanding of weakly accreting black holes in the local
universe, a large sample of galaxies with X-ray detections is needed. We
cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan
Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because
of the high SDSS source density and large RASS positional errors, the
cross-matched catalog is highly contaminated by random associations. We
investigate the overlap of these surveys and provide a statistical test of the
validity of RASS-SDSS galaxy cross-matches. SDSS quasars provide a test of our
cross-match validation scheme, as they have a very high fraction of true RASS
matches. We find that the number of true matches between the SDSS main galaxy
sample and the RASS is highly dependent on the optical spectral classification
of the galaxy; essentially no star-forming galaxies are detected, while more
than 0.6% of narrow-line Seyferts are detected in the RASS. Also, galaxies with
ambiguous optical classification have a surprisingly high RASS detection
fraction. This allows us to further constrain the SEDs of low-luminosity active
galaxies. Our technique is quite general, and can be applied to any
cross-matching between surveys with well-understood positional errors.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:58:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Parejko",
"John K.",
"",
"Drexel\n University"
],
[
"Constantin",
"Anca",
"",
"Drexel\n University"
],
[
"Vogeley",
"Michael S.",
"",
"Drexel\n University"
],
[
"Hoyle",
"Fiona",
"",
"Widener University"
]
] |
0706.3203 | Pasquale Dario Serpico | Dan Hooper and Pasquale D. Serpico | Detecting Axion-Like Particles With Gamma Ray Telescopes | corrected typos, one plot modified, material rearranged for
clarification. Conclusions unchanged. Matches version published in Phys. Rev.
Lett | Phys.Rev.Lett.99:231102,2007 | 10.1103/PhysRevLett.99.231102 | FERMILAB-PUB-07-190-A | hep-ph astro-ph | null | We propose that axion-like particles (ALPs) with a two-photon vertex,
consistent with all astrophysical and laboratory bounds, may lead to a
detectable signature in the spectra of high-energy gamma ray sources. This
occurs as a result of gamma rays being converted into ALPs in the magnetic
fields of efficient astrophysical accelerators according to the "Hillas
criterion", such as jets of active galactic nuclei or hot spots of radio
galaxies. The discovery of such an effect is possible by GLAST in the 1-100 GeV
range and by ground based gamma ray telescopes in the TeV range.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 17:54:38 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Dec 2007 17:24:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hooper",
"Dan",
""
],
[
"Serpico",
"Pasquale D.",
""
]
] |
0706.3204 | Paulina Marian | Paulina Marian, Tudor A. Marian | Optimal purifications and fidelity for displaced thermal states | published version | Physical Review A 76, 054307 (2007) | 10.1103/PhysRevA.76.054307 | null | quant-ph | null | We evaluate the Uhlmann fidelity between two one-mode displaced thermal
states as the maximal probability transition between appropriate purifications
of the given states. The optimal purifications defining the fidelity are proved
to be two-mode displaced Gaussian states.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:07:41 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Nov 2007 21:35:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Marian",
"Paulina",
""
],
[
"Marian",
"Tudor A.",
""
]
] |
0706.3205 | Dimitris Christodoulou | Dimitris M. Christodoulou and Demosthenes Kazanas | Exact Solutions of the Isothermal Lane--Emden Equation with Rotation and
Implications for the Formation of Planets and Satellites | Modified version with longer historical introduction, discussion of
model stability, and updated discussion of multi-planet extrasolar systems | null | null | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We have derived exact solutions of the isothermal Lane--Emden equation with
and without rotation in a cylindrical geometry. The corresponding hydrostatic
equilibria are most relevant to the dynamics of the protosolar nebula before
and during the stages of planet and satellite formation. The nonrotating
solution for the mass density is analytic, nonsingular, monotonically
decreasing with radius, and it satisfies easily the usual physical boundary
conditions at the center. When differential rotation is added to the
Lane--Emden equation, an entire class of exact solutions for the mass density
appears. We have determined all of these solutions analytically as well. Within
this class, solutions that are power laws or combinations of power laws are not
capable of satisfying the associated boundary--value problem, but they are
nonetheless of profound importance because they constitute "baselines" to which
the actual solutions approach when the central boundary conditions are imposed.
Numerical integrations that enforce such physical boundary conditions show that
the actual radial equilibrium density profiles emerge from the center close to
the nonrotating solution, but once they cross below the corresponding
baselines, they cease to be monotonic. The actual solutions are forced to
oscillate permanently about the baseline solutions without ever settling onto
them because the central boundary conditions strictly prohibit such settling,
even in the asymptotic regime of large radii. Based on our results, we expect
that quasistatically--evolving protoplanetary disks should develop oscillatory
density profiles in their midplanes during their isothermal phase. The peaks in
these profiles correspond to local potential minima and their locations are
ideal sites for the formation of protoplanets ...
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:19:54 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Nov 2008 04:43:37 GMT"
}
] | 2008-11-06T00:00:00 | [
[
"Christodoulou",
"Dimitris M.",
""
],
[
"Kazanas",
"Demosthenes",
""
]
] |
0706.3206 | Erika Grundstrom | E. D. Grundstrom, D. R. Gies, T. C. Hillwig, M. V. McSwain, N. Smith,
R. D. Gehrz, O. Stahl, A. Kaufer | A Spectroscopic Study of Mass Outflows in the Interacting Binary RY
Scuti | 41 pages with 7 tables and 11 figures, accepted to ApJ | Astrophys.J.667:505-519,2007 | 10.1086/521043 | null | astro-ph | null | The massive interacting binary RY Scuti is an important representative of an
active mass-transferring system that is changing before our eyes and which may
be an example of the formation of a Wolf-Rayet star through tidal stripping.
Utilizing new and previously published spectra, we present examples of how a
number of illustrative absorption and emission features vary during the binary
orbit. We identify spectral features associated with each component, calculate
a new, double-lined spectroscopic binary orbit, and find masses of 7.1 +/- 1.2
M_sun for the bright supergiant and 30.0 +/- 2.1 M_sun for the hidden massive
companion. Through tomographic reconstruction of the component spectra from the
composite spectra, we confirm the O9.7 Ibpe spectral class of the bright
supergiant and discover a B0.5 I spectrum associated with the hidden massive
companion; however, we suggest that the latter is actually the spectrum of the
photosphere of the accretion torus immediately surrounding the massive
companion. We describe the complex nature of the mass loss flows from the
system in the context of recent hydrodynamical models for beta Lyr, leading us
to conclude RY Scuti has matter leaving the system in two ways: 1) a bipolar
outflow from winds generated by the hidden massive companion, and 2) mass from
the bright O9.7 Ibpe supergiant flowing from the region near the L2 point to
fill out a large, dense circumbinary disk. This circumbinary disk (radius ~ 1
AU) may feed the surrounding double-toroidal nebula (radius ~ 2000 AU).
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:20:55 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Grundstrom",
"E. D.",
""
],
[
"Gies",
"D. R.",
""
],
[
"Hillwig",
"T. C.",
""
],
[
"McSwain",
"M. V.",
""
],
[
"Smith",
"N.",
""
],
[
"Gehrz",
"R. D.",
""
],
[
"Stahl",
"O.",
""
],
[
"Kaufer",
"A.",
""
]
] |
0706.3207 | Denis Auroux | Denis Auroux | Mirror symmetry and T-duality in the complement of an anticanonical
divisor | 42 pages, 2 figures; v2: some bibliographical references added | null | null | null | math.SG math.AG math.DG | null | We study the geometry of complexified moduli spaces of special Lagrangian
submanifolds in the complement of an anticanonical divisor in a compact Kahler
manifold. In particular, we explore the connections between T-duality and
mirror symmetry in concrete examples, and show how quantum corrections arise in
this context.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:30:55 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 13:00:26 GMT"
}
] | 2007-07-10T00:00:00 | [
[
"Auroux",
"Denis",
""
]
] |
0706.3208 | Elizabeth Werbos | Thomas D. Cohen, David A. McGady, Elizabeth S. Werbos | The chiral condensate in a constant electromagnetic field | 9 pages, 6 figures, LaTeX; removed extraneous section + minor
revisions | Phys.Rev.C76:055201,2007 | 10.1103/PhysRevC.76.055201 | null | hep-ph | null | We study the shift of the chiral condensate in a constant electromagnetic
field in the context of chiral perturbation theory. Using the Schwinger
proper-time formalism, we derive a one-loop expression correct to all orders in
$m_{\pi}^2 / eH$. Our result correctly reproduces a previously derived
``low-energy theorem'' for $m_\pi = 0$. We show that it is essential to include
corrections due to non-vanishing $m_\pi$ in order for a low energy theorem to
have any approximate regime of validity in the physical universe. We generalize
these results to systems containing electric fields, and discuss the regime of
validity for the results. In particular, we discuss the circumstances in which
the method formally breaks down due to pair creation in an electric field.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:47:41 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 17:28:38 GMT"
},
{
"version": "v3",
"created": "Wed, 10 Oct 2007 15:07:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cohen",
"Thomas D.",
""
],
[
"McGady",
"David A.",
""
],
[
"Werbos",
"Elizabeth S.",
""
]
] |
0706.3209 | Carlo Luciano Bianco | Maria Giovanna Dainotti, Maria Grazia Bernardini, Carlo Luciano
Bianco, Letizia Caito, Roberto Guida, Remo Ruffini | GRB060218 and GRBs associated with Supernovae Ib/c | 4 pages, 3 figures, to appear in A&A Letters | Astron.Astrophys. 471 (2007) L29-L32 | 10.1051/0004-6361:20078068 | null | astro-ph | null | We plan to fit the complete gamma- and X-ray light curves of the long
duration GRB060218, including the prompt emission, in order to clarify the
nature of the progenitors and the astrophysical scenario of the class of GRBs
associated to SNe Ib/c. The initial total energy of the electron-positron
plasma E_{e^\pm}^{tot}=2.32\times 10^{50} erg has a particularly low value
similarly to the other GRBs associated with SNe. For the first time we observe
a baryon loading B=10^{-2} which coincides with the upper limit for the
dynamical stability of the fireshell. The effective CircumBurst Medium (CBM)
density shows a radial dependence n_{cbm} \propto r^{-\alpha} with
1.0<\alpha<1.7 and monotonically decreases from 1 to 10^{-6} particles/cm^3.
Such a behavior is interpreted as due to a fragmentation in the fireshell.
Analogies with the fragmented density and filling factor characterizing Novae
are outlined. The fit presented is particularly significant in view of the
complete data set available for GRB060218 and of the fact that it fulfills the
Amati relation. We fit GRB060218, usually considered as an X-Ray Flash (XRF),
as a "canonical GRB" within our theoretical model. The smallest possible black
hole, formed by the gravitational collapse of a neutron star in a binary
system, is consistent with the especially low energetics of the class of GRBs
associated with SNe Ib/c. We give the first evidence for a fragmentation in the
fireshell. Such a fragmentation is crucial in explaining both the unusually
large T_{90} and the consequently inferred abnormal low value of the CBM
effective density.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 18:31:07 GMT"
}
] | 2017-02-15T00:00:00 | [
[
"Dainotti",
"Maria Giovanna",
""
],
[
"Bernardini",
"Maria Grazia",
""
],
[
"Bianco",
"Carlo Luciano",
""
],
[
"Caito",
"Letizia",
""
],
[
"Guida",
"Roberto",
""
],
[
"Ruffini",
"Remo",
""
]
] |
0706.3210 | Massimiliano Stengel | Massimiliano Stengel and Nicola A. Spaldin | Self-interaction correction with Wannier functions | 10 pages, 5 figures | Phys. Rev. B 77, 155106 (2008) | 10.1103/PhysRevB.77.155106 | null | cond-mat.other | null | We describe the behavior of the Perdew-Zunger self-interaction-corrected
local density approximation (SIC-LDA) functional when implemented in a
plane-wave pseudopotential formalism with Wannier functions. Prototypical
semiconductors and wide-bandgap oxides show a large overcorrection of the LDA
bandgap. Application to transition-metal oxides and elements with d electrons
is hindered by a serious breaking of the spherical symmetry, which appears even
in a closed shell free atom. Our results indicate that, when all spherical
approximations are lifted, the general applicability of orbital-dependent
potentials is very limited and should be reconsidered in favor of rotationally
invariant functionals.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:44:35 GMT"
}
] | 2011-03-03T00:00:00 | [
[
"Stengel",
"Massimiliano",
""
],
[
"Spaldin",
"Nicola A.",
""
]
] |
0706.3211 | Ophir Flomenbom | O. Flomenbom and R. J. Silbey | Path probability density functions for semi-Markovian random walks | null | Phys. Rev. E 76, 041101 (2007) | 10.1103/PhysRevE.76.041101 | null | math-ph math.MP physics.bio-ph q-bio.OT | null | In random walks, the path representation of the Green's function is an
infinite sum over the length of path probability density functions (PDFs). Here
we derive and solve, in Laplace space, the recursion relation for the n order
path PDF for any arbitrarily inhomogeneous semi-Markovian random walk in a
one-dimensional (1D) chain of L states. The recursion relation relates the n
order path PDF to L/2 (round towards zero for an odd L) shorter path PDFs, and
has n independent coefficients that obey a universal formula. The z transform
of the recursion relation straightforwardly gives the generating function for
path PDFs, from which we obtain the Green's function of the random walk, and
derive an explicit expression for any path PDF of the random walk. These
expressions give the most detailed description of arbitrarily inhomogeneous
semi-Markovian random walks in 1D.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:53:37 GMT"
}
] | 2019-08-19T00:00:00 | [
[
"Flomenbom",
"O.",
""
],
[
"Silbey",
"R. J.",
""
]
] |
0706.3212 | Patricio S. Letelier | Val\'eria M. Rosa and Patricio S. Letelier | Linear Stability of Closed Timelike Geodesics | 7 pages, RevTex, minor changes to match the published version | in Goedel-type spacetimes: History and new developments, M. Plaue
and M. Scherfner Eds., Kurt Goedel Society Collegium Logicum v. X, pp.
129-139 (2010) | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The linear stability of closed timelike geodesics (CTGs) is analyzed in two
spacetimes with cylindrical sources, an infinite rotating dust cylinder, and a
cylindrical cloud of static cosmic strings with a central spinning string. We
also study the existence and linear stability of closed timelike curves in
spacetimes that share some common features with the G\"odel universe
(G\"odel-type spacetimes). In this case the existence of CTGs depends on the
`background' metric. The CTGs in a subclass of inhomogeneous stationary
cosmological solutions of the Einstein-Maxwell equations with topology $
S^3\times \mathbb R$ are also examined.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 19:57:29 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Jan 2011 19:24:30 GMT"
}
] | 2011-01-26T00:00:00 | [
[
"Rosa",
"Valéria M.",
""
],
[
"Letelier",
"Patricio S.",
""
]
] |
0706.3213 | Dale Jackson | Dale C. Jackson, Evan D. Skillman, Robert D. Gehrz, Elisha Polomski,
and Charles E. Woodward | A Spitzer IRAC Census of the Asymptotic Giant Branch Populations in
Local Group Dwarfs. II. IC 1613 | Accepted by ApJ, 26 pages, 10 figures, version with high-resolution
figures available at: http://webusers.astro.umn.edu/~djackson/ | null | 10.1086/520912 | null | astro-ph | null | We present Spitzer Space Telescope IRAC photometry of the Local Group dwarf
irregular galaxy IC 1613. We compare our 3.6, 4.5, 5.8, and 8.0 micron
photometry with broadband optical photometry and find that the optical data do
not detect 43% and misidentify an additional 11% of the total AGB population,
likely because of extinction caused by circumstellar material. Further, we find
that a narrowband optical carbon star study of IC 1613 detects 50% of the total
AGB population and only considers 18% of this population in calculating the
carbon to M-type AGB ratio. We derive an integrated mass-loss rate from the AGB
stars of 0.2-1.0 x 10^(-3) solar masses per year and find that the distribution
of bolometric luminosities and mass-loss rates are consistent with those for
other nearby metal-poor galaxies. Both the optical completeness fractions and
mass-loss rates in IC 1613 are very similar to those in the Local Group dwarf
irregular, WLM, which is expected given their similar characteristics and
evolutionary histories.
| [
{
"version": "v1",
"created": "Thu, 21 Jun 2007 20:01:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jackson",
"Dale C.",
""
],
[
"Skillman",
"Evan D.",
""
],
[
"Gehrz",
"Robert D.",
""
],
[
"Polomski",
"Elisha",
""
],
[
"Woodward",
"Charles E.",
""
]
] |
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