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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.4130 | Antonio De Santis | KLOE collaboration: F. Ambrosino, A. Antonelli, M. Antonelli, F.
Archilli, C. Bacci, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C.
Bloise, S. Bocchetta, V. Bocci, F. Bossi, P. Branchini, R. Caloi, P. Campana,
G. Capon, T. Capussela, F. Ceradini, S. Chi, G. Chiefari, P. Ciambrone, E. De
Lucia, A. De Santis, P. De Simone, G. De Zorzi, A. Denig, A. Di Domenico, C.
Di Donato, S. Di Falco, B. Di Micco, A. Doria, M. Dreucci, G. Felici, A.
Ferrari, M. L. Ferrer, G. Finocchiaro, S. Fiore, C. Forti, P. Franzini, C.
Gatti, P. Gauzzi, S. Giovannella, E. Gorini, E. Graziani, M. Incagli, W.
Kluge, V. Kulikov, F. Lacava, G. Lanfranchi, J. Lee-Franzini, D. Leone, M.
Martini, P. Massarotti, W. Mei, S. Meola, S. Miscetti, M. Moulson, S.
M\"uller, F. Murtas, M. Napolitano, F. Nguyen, M. Palutan, E. Pasqualucci, A.
Passeri, V. Patera a, f, F. Perfetto, M. Primavera, P. Santangelo, G.
Saracino, B. Sciascia, A. Sciubba (1,6), F. Scuri, I. Sfiligoi, T. Spadaro,
M. Testa, L. Tortora, P. Valente, B. Valeriani, G. Venanzoni, R. Versaci, G.
Xu | Study of the process e+e- -> omega p0 with the KLOE detector | Contributed paper to Lepton Photon 2007 | null | null | null | hep-ex | null | Using ~600 pb-1 collected with the KLOE detector at DAPhiNE, we have studied
the production cross section of pi+ pi- pi0 pi0 and p0p0 gamma final states in
e+e- collisions at center of mass energies between 1000 and 1030 MeV. By
fitting the observed interference pattern around Mphi for both final states, we
extract a measurement (preliminary) for the ratio Gamma(omega -> pi0
gamma)/Gamma(omega -> pi+ pi- pi0) = 0.0934 +- 0.0022. Since these two final
states represent the 98% of the omega decay channels, we use unitarity to
derive BR(omega -> pi+pi-pi0)= (89.94 +- 0.23)% and BR(omega -> pi0 gamma) =
(8.40 +- 0.19)%. Moreover, the parameters describing the e+e- -> pi+ pi- pi0
pi0 reaction around Mphi are used to extract the branching fraction for the OZI
and G-parity violating phi -> omega pi0 decay: BR(phi -> omega pi0) = (5.63 +-
0.70) x 10^-5.
| [
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"created": "Fri, 27 Jul 2007 14:30:07 GMT"
},
{
"version": "v2",
"created": "Fri, 16 May 2008 13:28:23 GMT"
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] | 2008-05-16T00:00:00 | [
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""
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[
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""
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""
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[
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""
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""
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"M. L.",
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"Giovannella",
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"M.",
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[
"Nguyen",
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"Passeri",
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"a",
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],
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"f",
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],
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"Perfetto",
"F.",
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],
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"Primavera",
"M.",
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"Santangelo",
"P.",
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],
[
"Saracino",
"G.",
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[
"Sciascia",
"B.",
""
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[
"Sciubba",
"A.",
""
],
[
"Scuri",
"F.",
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[
"Sfiligoi",
"I.",
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"Spadaro",
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"Testa",
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[
"Tortora",
"L.",
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],
[
"Valente",
"P.",
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],
[
"Valeriani",
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"Venanzoni",
"G.",
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[
"Versaci",
"R.",
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[
"Xu",
"G.",
""
]
] |
0707.4131 | Maria Bergemann | Maria Bergemann (1) and Thomas Gehren (1) ((1) Institute for Astronomy
and Astrophysics, Ludwig-Maximilian University) | Formation of MnI lines in the solar atmosphere | 17 pages, 27 figures, accepted for publication in A&A | null | 10.1051/0004-6361:20066810 | null | astro-ph | null | We present a detailed NLTE analysis of 39 MnI lines in the solar spectrum.
The influence of NLTE effects on the line formation and element abundance is
investigated. Our goal is the derivation of solar log gfe values for manganese
lines, which will later be used in differential abundance analysis of
metal-poor stars. The method of spectrum synthesis is employed, which is based
on a solar model atmosphere with initially specified element abundances. A
manganese abundance of 5.47 dex is used with the theoretical line-blanketed
model atmosphere. Statistical equilibrium calculations are carried out for the
model atom, which comprises 245 and 213 levels for MnI and MnII, respectively.
Photoionization cross-sections are assumed hydrogenic. For line synthesis van
der Waals broadening is calculated according to Anstee & O'Mara's formalism. It
is shown that hyperfine structure of the Mn lines also has strong broadening
effects, and that manganese is prone to NLTE effects in the solar atmosphere.
The nature of the NLTE effects and the validity of the LTE approach are
discussed in detail. The role of photoionization and collisional interaction is
investigated.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 14:33:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bergemann",
"Maria",
""
],
[
"Gehren",
"Thomas",
""
]
] |
0707.4132 | Robert Intemann | Robert L. Intemann | Comment on "On an identity for the volume integral of the square of a
vector field" | 5 pages | null | 10.1119/1.2794347 | null | physics.class-ph physics.ed-ph | null | Stewart has provided a position-space derivation of an identity for the
volume integral of the square of a vector field that was quoted by Gubarev,
Stodolsky and Zakharov. In this comment, I provide a momentum-space derivation
of this result, generalized to the scalar product of two complex vector fields.
This approach demonstrates the effective use of the Fourier transform technique
in the context of vector analysis at a level suitable for undergraduate
instruction.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 14:44:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Intemann",
"Robert L.",
""
]
] |
0707.4133 | Chao Tian | Chao Tian, Jun Chen and Suhas Diggavi | Multiuser Successive Refinement and Multiple Description Coding | 10 pages, 5 figures. To appear in IEEE Transaction on Information
Theory. References updated and typos corrected | null | null | null | cs.IT math.IT | null | We consider the multiuser successive refinement (MSR) problem, where the
users are connected to a central server via links with different noiseless
capacities, and each user wishes to reconstruct in a successive-refinement
fashion. An achievable region is given for the two-user two-layer case and it
provides the complete rate-distortion region for the Gaussian source under the
MSE distortion measure. The key observation is that this problem includes the
multiple description (MD) problem (with two descriptions) as a subsystem, and
the techniques useful in the MD problem can be extended to this case. We show
that the coding scheme based on the universality of random binning is
sub-optimal, because multiple Gaussian side informations only at the decoders
do incur performance loss, in contrast to the case of single side information
at the decoder. We further show that unlike the single user case, when there
are multiple users, the loss of performance by a multistage coding approach can
be unbounded for the Gaussian source. The result suggests that in such a
setting, the benefit of using successive refinement is not likely to justify
the accompanying performance loss. The MSR problem is also related to the
source coding problem where each decoder has its individual side information,
while the encoder has the complete set of the side informations. The MSR
problem further includes several variations of the MD problem, for which the
specialization of the general result is investigated and the implication is
discussed.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:21:48 GMT"
},
{
"version": "v2",
"created": "Tue, 13 Nov 2007 14:45:55 GMT"
}
] | 2007-11-13T00:00:00 | [
[
"Tian",
"Chao",
""
],
[
"Chen",
"Jun",
""
],
[
"Diggavi",
"Suhas",
""
]
] |
0707.4134 | Hans U. Boden | Hans U. Boden, Cynthia L. Curtis | Splicing and the SL(2,C) Casson invariant | 9 pages, 2 figures, to appear in Proc. of the A.M.S | Proc. Amer. Math. Soc. 136 (2008) 2615-2623 | 10.1090/S0002-9939-08-09233-2 | null | math.GT | null | We establish a formula for the SL(2,C) Casson invariant of spliced sums of
homology spheres along knots. Along the way, we show that the SL(2,C) Casson
invariant vanishes for spliced sums along knots in the 3-sphere.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:17:14 GMT"
}
] | 2021-09-29T00:00:00 | [
[
"Boden",
"Hans U.",
""
],
[
"Curtis",
"Cynthia L.",
""
]
] |
0707.4135 | Helena Mihaljevic-Brandt | Helena Mihaljevic-Brandt | A landing theorem for dynamic rays of geometrically finite entire
functions | 19 pages, 4 figures. results have been extended to a larger class of
functions | J. London Math. Soc. 81 (2010) 696-714 | 10.1112/jlms/jdq014 | null | math.DS | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A transcendental entire function f is called geometrically finite if the
intersection of the set of singular values with the Fatou set is compact and
the intersection of the postsingular set with the Julia set is finite. (In
particular, this includes all entire functions with finite postsingular set.)
If f is geometrically finite, then the Fatou set of f is either empty or
consists of the basins of attraction of finitely many attracting or parabolic
cycles.
Let z_0 be a repelling or parabolic periodic point of such a map f. We show
that, if f has finite order, then there exists an injective curve consisting of
escaping points of f that connects z_0 to infinity. (This curve is called a
dynamic ray.) In fact, the assumption of finite order can be weakened
considerably; for example, it is sufficient to assume that f can be written as
a finite composition of finite-order functions.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:18:58 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Feb 2009 14:52:53 GMT"
}
] | 2010-11-02T00:00:00 | [
[
"Mihaljevic-Brandt",
"Helena",
""
]
] |
0707.4136 | Ambar Sengupta | Ambar N. Sengupta | Gauge Theory in Two Dimensions: Topological, Geometric and Probabilistic
Aspects | 16 pages, presented at a conference titled Stochastic Analysis and
Mathematical Physics 2006, organized by Ana Bela Cruzeiro and Jean-Claude
Zambrini | null | null | null | hep-th math-ph math.MP | null | We present a description of two dimensional Yang-Mills gauge theory on the
plane and on compact surfaces, examining the topological, geometric and
probabilistic aspects.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:46:33 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Sengupta",
"Ambar N.",
""
]
] |
0707.4137 | Francesco Perfetto | KLOE collaboration: F. Ambrosino, A. Antonelli, M. Antonelli, F.
Archilli, C. Bacci, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C.
Bloise, S. Bocchetta, V. Bocci, F. Bossi, P. Branchini, R. Caloi, P. Campana,
G. Capon, T. Capussela, F. Ceradini, S. Chi, G. Chiefari, P. Ciambrone, E. De
Lucia, A. De Santis, P. De Simone, G. De Zorzi, A. Denig, A. Di Domenico, C.
Di Donato, S. Di Falco, B. Di Micco, A. Doria, M. Dreucci, G. Felici, A.
Ferrari, M.L. Ferrer, G. Finocchiaro, S. Fiore, C. Forti, P. Franzini, C.
Gatti, P. Gauzzi, S. Giovannella, E. Gorini, E. Graziani, M. Incagli, W.
Kluge, V. Kulikov, F. Lacava, G. Lanfranchi, J. Lee-Franzini, D. Leone, M.
Martini, P. Massarotti, W. Mei, S. Meola, S. Miscetti, M. Moulson, S.
M\"uller, F. Murtas, M. Napolitano, F. Nguyen, M. Palutan, E. Pasqualucci, A.
Passeri, V. Patera, F. Perfetto, M. Primavera, P. Santangelo, G. Saracino, B.
Sciascia, A. Sciubba, F. Scuri, I. Sfiligoi, T. Spadaro, M. Testa, L.
Tortora, P. Valente, B. Valeriani, G. Venanzoni, R. Versaci, G. Xu | Measurement of the slope parameter \alpha for the \eta\to 3\pi^0 decay
at KLOE | " Contributed paper to Lepton-Photon 2007 ". 5 pages, 4 figures | null | null | null | hep-ex | null | We report a preliminary measurement of the slope parameter $\alpha$ for the
$\eta\to 3\piz$ decay carried out with KLOE at DA$\Phi$NE; where $\alpha$ is
the parameter describing the energy dependence of the square of the matrix
element for this decay. By fitting the event density in the Dalitz plot with a
collected statistic of 420 pb$^{-1}$ we determine $\alpha = -0.027 \pm 0.004
(stat) ^{+0.004}_{-0.006} (syst)$. This result is consistent with current
chiral perturbation theory calculations within the unitary approach.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:24:14 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"KLOE collaboration",
"",
""
],
[
"Ambrosino",
"F.",
""
],
[
"Antonelli",
"A.",
""
],
[
"Antonelli",
"M.",
""
],
[
"Archilli",
"F.",
""
],
[
"Bacci",
"C.",
""
],
[
"Beltrame",
"P.",
""
],
[
"Bencivenni",
"G.",
""
],
[
"Bertolucci",
"S.",
""
],
[
"Bini",
"C.",
""
],
[
"Bloise",
"C.",
""
],
[
"Bocchetta",
"S.",
""
],
[
"Bocci",
"V.",
""
],
[
"Bossi",
"F.",
""
],
[
"Branchini",
"P.",
""
],
[
"Caloi",
"R.",
""
],
[
"Campana",
"P.",
""
],
[
"Capon",
"G.",
""
],
[
"Capussela",
"T.",
""
],
[
"Ceradini",
"F.",
""
],
[
"Chi",
"S.",
""
],
[
"Chiefari",
"G.",
""
],
[
"Ciambrone",
"P.",
""
],
[
"De Lucia",
"E.",
""
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"De Santis",
"A.",
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],
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"De Simone",
"P.",
""
],
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"De Zorzi",
"G.",
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"Denig",
"A.",
""
],
[
"Di Domenico",
"A.",
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],
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"Di Donato",
"C.",
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"Di Falco",
"S.",
""
],
[
"Di Micco",
"B.",
""
],
[
"Doria",
"A.",
""
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"Dreucci",
"M.",
""
],
[
"Felici",
"G.",
""
],
[
"Ferrari",
"A.",
""
],
[
"Ferrer",
"M. L.",
""
],
[
"Finocchiaro",
"G.",
""
],
[
"Fiore",
"S.",
""
],
[
"Forti",
"C.",
""
],
[
"Franzini",
"P.",
""
],
[
"Gatti",
"C.",
""
],
[
"Gauzzi",
"P.",
""
],
[
"Giovannella",
"S.",
""
],
[
"Gorini",
"E.",
""
],
[
"Graziani",
"E.",
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[
"Incagli",
"M.",
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],
[
"Kluge",
"W.",
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[
"Kulikov",
"V.",
""
],
[
"Lacava",
"F.",
""
],
[
"Lanfranchi",
"G.",
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[
"Lee-Franzini",
"J.",
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[
"Leone",
"D.",
""
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[
"Martini",
"M.",
""
],
[
"Massarotti",
"P.",
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],
[
"Mei",
"W.",
""
],
[
"Meola",
"S.",
""
],
[
"Miscetti",
"S.",
""
],
[
"Moulson",
"M.",
""
],
[
"Müller",
"S.",
""
],
[
"Murtas",
"F.",
""
],
[
"Napolitano",
"M.",
""
],
[
"Nguyen",
"F.",
""
],
[
"Palutan",
"M.",
""
],
[
"Pasqualucci",
"E.",
""
],
[
"Passeri",
"A.",
""
],
[
"Patera",
"V.",
""
],
[
"Perfetto",
"F.",
""
],
[
"Primavera",
"M.",
""
],
[
"Santangelo",
"P.",
""
],
[
"Saracino",
"G.",
""
],
[
"Sciascia",
"B.",
""
],
[
"Sciubba",
"A.",
""
],
[
"Scuri",
"F.",
""
],
[
"Sfiligoi",
"I.",
""
],
[
"Spadaro",
"T.",
""
],
[
"Testa",
"M.",
""
],
[
"Tortora",
"L.",
""
],
[
"Valente",
"P.",
""
],
[
"Valeriani",
"B.",
""
],
[
"Venanzoni",
"G.",
""
],
[
"Versaci",
"R.",
""
],
[
"Xu",
"G.",
""
]
] |
0707.4138 | Derek Homeier | Derek Homeier, Nicole F. Allard, Christine M. S. Johnas, Peter H.
Hauschildt, France Allard | Alkali Line Profiles in Ultracool White Dwarfs | 15th European Workshop on White Dwarfs (2006), ASP Conference Series
vol. 372, eds. R. Napiwotzki and M. R. Burleigh, 2007 - 6 pages, 4 figures | null | null | null | astro-ph | null | We present PHOENIX atmosphere models for metal-rich cool white dwarfs using
improved line shapes for the Na I and K I resonance doublets. Profiles for
collisional broadening due to H2 and He based on the adiabatic representation
show strong deviations from Van der Waals interaction at short distances.
Comparison with observed spectra that show extremely broadened Na I lines
indicates that a He-rich atmospheric composition is required to explain the
line strengths and spectral energy distributions. Our current synthetic
spectra, using an expansion in powers of density to the third order optimised
for brown dwarf atmosphere conditions, significantly underestimate the observed
absorption in the far wings, even predicting smaller total line strength than a
Lorentzian profile. This is due to the handling of multiple perturber
interactions becoming inadequate for the extreme densities of the coolest white
dwarfs. The density expansion would have to be extended at least to the 7th
order for an accurate treatment of such conditions and might break down
altogether in the densest objects. The results of a direct calculation of the
unified profile should therefore be used for model atmospheres of cool
metal-rich white dwarfs. Qualitative comparison of the full adiabatic profile
to the spectrum of WD2356-209 indicates good agreement with the observed line
shape. Observations of the coolest white dwarfs may therefore serve as a
laboratory for testing the physics of the deeper atmospheres and interiors of
brown dwarfs and giant planets.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:35:44 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jul 2007 11:35:08 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Homeier",
"Derek",
""
],
[
"Allard",
"Nicole F.",
""
],
[
"Johnas",
"Christine M. S.",
""
],
[
"Hauschildt",
"Peter H.",
""
],
[
"Allard",
"France",
""
]
] |
0707.4139 | Sven-Olaf Moch | M. Czakon, A. Mitov and S. Moch | Heavy-quark production in gluon fusion at two loops in QCD | 31 pages latex, 4 figures | null | 10.1016/j.nuclphysb.2008.02.001 | DESY 07-101, SFB/CPP-07-37 | hep-ph | null | We present the two-loop virtual QCD corrections to the production of heavy
quarks in gluon fusion. The results are exact in the limit when all kinematical
invariants are large compared to the mass of the heavy quark up to terms
suppressed by powers of the heavy-quark mass. Our derivation uses a simple
relation between massless and massive QCD scattering amplitudes as well as a
direct calculation of the massive amplitude at two loops. The results presented
here together with those obtained previously for quark-quark scattering form
important parts of the next-to-next-to-leading order QCD corrections to
heavy-quark production in hadron-hadron collisions.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:02:35 GMT"
}
] | 2010-04-05T00:00:00 | [
[
"Czakon",
"M.",
""
],
[
"Mitov",
"A.",
""
],
[
"Moch",
"S.",
""
]
] |
0707.4140 | Ama\"el Broustet | Ama\"el Broustet | Non-annulation effective et positivit\'e locale des fibr\'es en droites
amples adjoints | 22 pages, in french, typos corrected | null | null | null | math.AG | null | We prove that Seshadri constants of some ample divisors are bigger than 1 on
smooth threefolds whose anticanonical bundle is nef or on Fano varieties of
small coindice. The main tools are (some known cases of) the Kawamata's
effective non-vanishing conjecture and the adjunction theory. We prove the
non-vanishing conjecture in dimension 3 in the case of line bundles of "high"
volume using Kawamata's subadjunction formula.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:38:35 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 11:52:38 GMT"
},
{
"version": "v3",
"created": "Mon, 15 Oct 2007 08:21:58 GMT"
}
] | 2007-10-15T00:00:00 | [
[
"Broustet",
"Amaël",
""
]
] |
0707.4141 | Klaus Niederkr\"uger | Klaus Niederkr\"uger and Federica Pasquotto | Resolution of symplectic cyclic orbifold singularities | 12 pages, 2 figures: proof by performing a symplectic cut of the
Hamiltonian S^1-manifold, 1 figure added | null | 10.4310/JSG.2009.v7.n3.a4 | null | math.SG | null | In this paper we present a method to obtain resolutions of symplectic
orbifolds arising from symplectic reduction of a Hamiltonian S^1-manifold at a
regular value. As an application, we show that all isolated cyclic
singularities of a symplectic orbifold admit a resolution and that
pre-quantisations of symplectic orbifolds are symplectically fillable by a
smooth manifold.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:44:53 GMT"
},
{
"version": "v2",
"created": "Sun, 9 Dec 2007 21:09:42 GMT"
}
] | 2015-10-27T00:00:00 | [
[
"Niederkrüger",
"Klaus",
""
],
[
"Pasquotto",
"Federica",
""
]
] |
0707.4142 | Michael Kozlov | Misha Kozlov, Arif Shoshi and Wenchang Xiang | On possible implications of gluon number fluctuations in DIS data | 9 pages, 2 figures; references added, minor changes, matches
published version | JHEP 0710:020,2007 | 10.1088/1126-6708/2007/10/020 | BI-TP-2007-16 | hep-ph | null | We study the effect of gluon number fluctuations (Pomeron loops) on deep
inelastic scattering (DIS) in the fixed coupling case. We find that the
description of the DIS data is improved once gluon number fluctuations are
included. Also the values of the parameters, like the saturation exponent and
the diffussion coefficient, turn out reasonable and agree with values obtained
from numerical simulations of toy models which take into account fluctuations.
This outcome seems to indicate the evidence of geometric scaling violations,
and a possible implication of gluon number fluctuations, in the DIS data.
However, we cannot exclude the possibility that the scaling violations may also
come from the diffusion part of the solution to the BK-equation, instead of
gluon number fluctuations.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:49:34 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 16:22:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kozlov",
"Misha",
""
],
[
"Shoshi",
"Arif",
""
],
[
"Xiang",
"Wenchang",
""
]
] |
0707.4143 | Fabien Vignes-Tourneret | Adrian Tanasa, Fabien Vignes-Tourneret | Hopf algebra of non-commutative field theory | 14 pages, 4 figures | Journal of Noncommutative Geometry 2 (2008) 125 | 10.4171/JNCG/17 | LPT-ORSAY 07-58 | math-ph hep-th math.MP math.QA | null | We contruct here the Hopf algebra structure underlying the process of
renormalization of non-commutative quantum field theory.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:27:23 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 20:24:45 GMT"
}
] | 2013-08-15T00:00:00 | [
[
"Tanasa",
"Adrian",
""
],
[
"Vignes-Tourneret",
"Fabien",
""
]
] |
0707.4144 | Nobuyuki Kanematsu Ph.D. | Nobuyuki Kanematsu, Shunsuke Yonai, and Azusa Ishizaki | The grid-dose-spreading algorithm for dose distribution calculation in
heavy charged particle radiotherapy | 7 pages, 3 figures | Medical Physics 35(2) 602-607, 2008 | 10.1118/1.2829878 | null | physics.med-ph | null | A new variant of the pencil-beam (PB) algorithm for dose distribution
calculation for radiotherapy with protons and heavier ions, the grid-dose
spreading (GDS) algorithm, is proposed. The GDS algorithm is intrinsically
faster than conventional PB algorithms due to approximations in convolution
integral, where physical calculations are decoupled from simple grid-to-grid
energy transfer. It was effortlessly implemented to a carbon-ion radiotherapy
treatment planning system to enable realistic beam blurring in the field, which
was absent with the broad-beam (BB) algorithm. For a typical prostate
treatment, the slowing factor of the GDS algorithm relative to the BB algorithm
was 1.4, which is a great improvement over the conventional PB algorithms with
a typical slowing factor of several tens. The GDS algorithm is mathematically
equivalent to the PB algorithm for horizontal and vertical coplanar beams
commonly used in carbon-ion radiotherapy while dose deformation within the size
of the pristine spread occurs for angled beams, which was within 3 mm for a
single proton pencil beam of $30^\circ$ incidence, and needs to be assessed
against the clinical requirements and tolerances in practical situations.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:11:09 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Nov 2007 08:57:27 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Kanematsu",
"Nobuyuki",
""
],
[
"Yonai",
"Shunsuke",
""
],
[
"Ishizaki",
"Azusa",
""
]
] |
0707.4145 | Juan Manuel Borrero | J.M. Borrero, L.R. Bellot Rubio, D.A.N. Mueller | Flux tubes as the origin of Net Circular Polarization in Sunspot
Penumbrae | Accepted for publication in ApJ Letters; 4 pages, 3 figures. Uses
emulated ApJ | null | 10.1086/521923 | null | astro-ph | null | We employ a 3-dimensional magnetohydrostatic model of a horizontal flux tube,
embedded in a magnetic surrounding atmosphere, to successfully reproduce the
azimuthal and center-to-limb variations of the Net Circular Polarization
observed in sunspot penumbrae. This success is partly due to the realistic
modeling of the interaction between the flux tube and the surrounding magnetic
field.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 15:48:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Borrero",
"J. M.",
""
],
[
"Rubio",
"L. R. Bellot",
""
],
[
"Mueller",
"D. A. N.",
""
]
] |
0707.4146 | Marian Anghel | Marian Anghel, Ingo Steinwart | Forecasting the Evolution of Dynamical Systems from Noisy Observations | 5 pages, 4 figures, 1 table | null | null | LA-UR-07-4751 | nlin.CD | null | We consider the problem of designing almost optimal predictors for dynamical
systems from a finite sequence of noisy observations and incomplete knowledge
of the dynamics and the noise. We first discuss the properties of the optimal
(Bayes) predictor and present the limitations of memory-free forecasting
methods, and of any finite memory methods in general. We then show that a
nonparametric support vector machine approach to forecasting can consistently
learn the optimal predictor for all pairs of dynamical systems and bounded
observational noise processes that possess summable correlation sequences.
Numerical experiments show that this approach adapts the memory length of the
forecaster to the complexity of the learning task and the size of the
observation sequence.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:18:34 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Anghel",
"Marian",
""
],
[
"Steinwart",
"Ingo",
""
]
] |
0707.4147 | Carlo Nipoti | Carlo Nipoti (1), James Binney (2) ((1) Bologna University, (2) Oxford
University) | The role of thermal evaporation in galaxy formation | MNRAS, accepted. Added discussion and references, conclusions
unchanged. 14 pages, 6 figures (2 color) | null | 10.1111/j.1365-2966.2007.12505.x | null | astro-ph | null | In colour-magnitude diagrams most galaxies fall in either the ``blue cloud''
or the ``red sequence'', with the red sequence extending to significantly
brighter magnitudes than the blue cloud. The bright-end of the red sequence
comprises elliptical galaxies (Es) with boxy isophotes and luminosity profiles
with shallow central cores, while fainter Es have disky isophotes and power-law
inner surface-brightness (SB) profiles. An analysis of published data reveals
that the centres of galaxies with power-law central SB profiles have younger
stellar populations than the centres of cored galaxies. We argue that thermal
evaporation of cold gas by virial-temperature gas plays an important role in
determining these phenomena. In less massive galaxies, thermal evaporation is
not very efficient, so significant amounts of cold gas can reach the galaxy
centre and fill a central core with newly formed stars, consistent with the
young stellar ages of the cusps of Es with power-law SB profiles. In more
massive galaxies, cold gas is evaporated within a dynamical time, so star
formation is inhibited, and a core in the stellar density profile produced by
dissipationless dynamics cannot be refilled. The different observed properties
of AGN in higher-mass and lower-mass ellipticals are also explained because in
the former the central black holes invariably accrete hot gas, while in the
latter they typically accrete cold gas. An important consequence of our results
is that at the present time there cannot be blue, star-forming galaxies in the
most massive galactic halos, consistent with the observed truncation of the
blue cloud at L*. [abridged]
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:52:16 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Sep 2007 14:01:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nipoti",
"Carlo",
""
],
[
"Binney",
"James",
""
]
] |
0707.4148 | Salvatore Fiore | KLOE collaboration | Search for phi to K0 K0bar gamma decay with KLOE | Contributed paper to Lepton Photon 2007 | null | null | null | hep-ex | null | The KLOE collaboration has searched for the phi to K0 K0bar gamma decay using
a sample of 1.4 fb-1 of e+e- collisions at W ~ M(phi) collected with the KLOE
experiment at the Frascati e+e- collider DAFNE. No previous search exists for
this decay, while many theory models predict a BR of 10-8 for this channel. We
set a preliminary value of the U.L. on this BR to 1.8x10-8 at 90% C.L.. This
limit rules out most of the existing theory predictions.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:11:57 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 13:40:28 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"KLOE collaboration",
"",
""
]
] |
0707.4149 | Yudong Tang | Xiuxiong Chen, Yudong Tang | Test configurations and Geodesic rays | 30 pages | null | null | null | math.DG math.AG | null | For smooth test configurations, there always exist C^{1,1} geodesic rays in
Kahler metric space parallel to the algebraic ray. The $\yen$ invariant agrees
with Futaki invariant, at least under nice assumptions. Explicit examples in
Toric cases are calculated. On simple test configurations, Donaldson's
correspondence between HCMA solution and holomorphic disc family is extended.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:51:30 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Chen",
"Xiuxiong",
""
],
[
"Tang",
"Yudong",
""
]
] |
0707.4150 | Reynier Peletier | A. Vazdekis (IAC, Tenerife) and R.F. Peletier (Kapteyn Astronomical
Institute) | IAU Symposium 241 - Stellar Populations as Building Blocks of Galaxies | This is the table of contents of the upcoming proceedings of IAU
Symposium 241. The book will appear in September, from Cambridge University
Press, and will also be available electronically at
http://www.journals.cambridge.org/action/displayJournal?jid=IAU | null | null | null | astro-ph | null | Stellar populations, building blocks of galaxies, are direct tracers of the
star formation history, the chemical enrichment and the assembly of galaxies in
the Universe. They therfore allow us to understand how galaxies formed and
evolved. This last decade has witnessed a revolution in our observations of
galaxies; with larger telescopes and new instruments we are not only able to
look deeper in the Universe, we can also study nearby galaxies with greater
detail. The fact that now is becoming possible to resolve stars up to the
distance of Virgo Cluster allows us to rigorously compare and calibrate the
analysis of the integrated light with resolved stellar populations. These
Proceedings report the considerable progress made in recent years in this
topic. Theorists and observers, researchers of resolved and unresolved stellar
populations, discussed the ingredients of stellar population models, and
rigorously compared them to new data, forcing theorists to develop more refined
models and methods to derive the physical parameters of the stellar
populations. New results from the Milky Way, the Local Group, and nearby and
distant galaxies were presented.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:05:01 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Vazdekis",
"A.",
"",
"IAC, Tenerife"
],
[
"Peletier",
"R. F.",
"",
"Kapteyn Astronomical\n Institute"
]
] |
0707.4151 | Shmatov Sergei | Alexander Lanyov and Sergei Shmatov | Studies of Drell-Yan dimuon events in the CMS experiment | Presented on behalf of the CMS Collaboration at Hadron Collider
Physics Symposium, 20-26 May 2007 La Biodola, Isola d'Elba, Italy | Nucl.Phys.Proc.Suppl.177-178:302-304,2008 | 10.1016/j.nuclphysbps.2007.11.136 | null | hep-ex | null | The potential of the Compact Muon Solenoid (CMS) experiment to measure
Drell-Yan muon pairs is discussed. Muon pairs can be measured in CMS with high
precision up to very high invariant masses. The systematic errors are
considered. The potential to carry out precise measurements of the
forward-backward asymmetry is discussed.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:08:12 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lanyov",
"Alexander",
""
],
[
"Shmatov",
"Sergei",
""
]
] |
0707.4152 | Johann Kroha | Michael Arnold, Tobias Langenbruch, and Johann Kroha (Universit"at
Bonn) | Stable two-channel Kondo fixed point of an SU(3) quantum defect in a
metal: renormalization group analysis and conductance spikes | 4 pages, 4 figures, published version, to appear in PRL | Phys. Rev. Lett. 99, 186601 (2007) | 10.1103/PhysRevLett.99.186601 | null | cond-mat.mes-hall cond-mat.str-el | null | We propose a physical realization of the two-channel Kondo (2CK) effect,
where a dynamical defect in a metal has a unique ground state and twofold
degenerate excited states. In a wide range of parameters the interactions with
the electrons renormalize the excited double downward below the bare defect
ground state, thus stabilizing the 2CK fixed point. In addition to the Kondo
temperature T_K the three-state defect exhibits another low-energy scale,
associated with ground-to-excited-state transitions, which can be exponentially
smaller than T_K. Using the perturbative nonequilibrium renormalization group
we demonstrate explicitly that this can provide the long-sought explanation of
the sharp conductance spikes observed by Ralph and Buhrman in ultrasmall
metallic point contacts.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:10:17 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jul 2007 15:40:46 GMT"
},
{
"version": "v3",
"created": "Sat, 29 Sep 2007 08:31:46 GMT"
}
] | 2008-02-04T00:00:00 | [
[
"Arnold",
"Michael",
"",
"Universit\"at\n Bonn"
],
[
"Langenbruch",
"Tobias",
"",
"Universit\"at\n Bonn"
],
[
"Kroha",
"Johann",
"",
"Universit\"at\n Bonn"
]
] |
0707.4153 | Constanze Metzger | Constanze Metzger, Ivan Favero, Alexander Ortlieb, Khaled Karrai | Opto-Mechanics of deformable Fabry-Perot Cavities | 26 pages, 7 figures | published in Physical Review B 78, 035309 (2008) | 10.1103/PhysRevB.78.035309 | null | cond-mat.other | null | We investigated the opto-mechanical properties of a Fabry-Perot cavity with a
mirror mounted on a spring. Such a structure allows the cavity length to change
elastically under the effect of light induced forces. This opto-mechanical
coupling is exploited to control the amplitude of mechanical fluctuation of the
mirror. We present a model developed in the classical limit and discuss data
obtained in the particular case for which photo-thermal forces are dominant.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 19:51:06 GMT"
},
{
"version": "v2",
"created": "Fri, 27 Jul 2007 20:19:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Metzger",
"Constanze",
""
],
[
"Favero",
"Ivan",
""
],
[
"Ortlieb",
"Alexander",
""
],
[
"Karrai",
"Khaled",
""
]
] |
0707.4154 | Francesco Becattini | F. Becattini | Remark on statistical model fits to particle ratios in relativistic
heavy ion collisions | 6 pages, 2 figures. Few changes in the text | null | null | null | nucl-th | null | In order to determine the chemical freeze-out parameters of the
hadron-emitting source in relativistic heavy ion collisions some studies in
literature perform fits by using as data input a subsample of ratios calculated
out of experimentally measured hadron yields instead of yields themselves. We
show that this is a statistically incorrect method fit, implying a bias in the
extracted parameters.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:19:42 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Sep 2007 13:36:50 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Becattini",
"F.",
""
]
] |
0707.4155 | Gloria Sala | Gloria Sala, Jochen Greiner, Marco Ajello, Eugenio Bottacini, Franck
Haberl | XMM-Newton and INTEGRAL observations of the black hole candidate XTE
J1817-330 | Accepted for publication in A&A | null | 10.1051/0004-6361:20077360 | null | astro-ph | null | The galactic black hole candidate XTE J1817-330 was discovered in outburst by
RXTE in January 2006. We present here the results of an XMM-Newton Target of
opportunity observation (TOO), performed on 13 March 2006 (44 days after the
maximum), and an INTEGRAL observation performed on 15-18 February 2006 (18 days
after the maximum). The EPIC-pn camera on-board XMM-Newton was used in the fast
read-out Burst mode to avoid photon pile-up, while the RGSs were used in
Spectroscopy high count-rate mode. We fit both the XMM-Newton and the INTEGRAL
spectra with a two-component model consisting of a thermal accretion disk and a
comptonizing hot corona. The soft X-ray spectrum is dominated by an accretion
disk component, with a maximum temperature decreasing from 0.96+/-0.04 keV at
the time of the INTEGRAL observation to 0.70+/-m0.01 keV on 13 March. The
Optical Monitors on board INTEGRAL and XMM-Newton showed the source with
magnitudes V: 11.3-11.4, U:15.0-15.1 and UVW1:14.7-14.8. The soft X-ray
spectrum, together with the optical and UV data, show a low hydrogen column
density towards the source, and several absorption lines, most likely of
interstellar origin, are detected in the RGS spectrum: OI K-alpha, OI K-beta,
OII, OIII and OVII, which trace both cold and hot components of the ISM. The
soft X-ray spectrum indicates the presence of a black hole, with an estimate
for the upper limit of the mass of 6.0(+4.0/-2.5) Msun.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:31:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sala",
"Gloria",
""
],
[
"Greiner",
"Jochen",
""
],
[
"Ajello",
"Marco",
""
],
[
"Bottacini",
"Eugenio",
""
],
[
"Haberl",
"Franck",
""
]
] |
0707.4156 | Boris V. Fine | B. V. Fine, J. P. R. Bakker and J. I. Dijkhuis | Long-range fluctuations of random potential landscape as a mechanism of
1/f noise in hydrogenated amorphous silicon | 14 pages, 3 figures, final version | Fluctuations and Noise Letters, v. 5, pp. L443-L456 (2005) | null | null | cond-mat.stat-mech cond-mat.dis-nn cond-mat.mtrl-sci | null | We describe a mechanism, which links the long-range potential fluctuations
induced by charged defects to the low frequency resistance noise widely known
as 1/f noise. This mechanism is amenable to the first principles microscopic
calculation of the noise spectrum, which includes the absolute noise intensity.
We have performed such a calculation for the thin films of hydrogenated
amorphous silicon (a-Si:H) under the condition that current flows perpendicular
to the plane of the films, and found a very good agreement between the
theoretical noise intensity and the measured one. The mechanism described is
quite general. It should be present in a broad class of systems containing
poorly screened charged defects.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:39:08 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Fine",
"B. V.",
""
],
[
"Bakker",
"J. P. R.",
""
],
[
"Dijkhuis",
"J. I.",
""
]
] |
0707.4157 | Vesna Mitrovic | V. F. Mitrovi\'c, G. Koutroulakis, M.-A. Vachon, M. Horvati\'c, C.
Berthier, G. Lapertot, J. Flouquet | Phase Diagram of CeCoIn_5 in the Vicinity of H_{c2} as Determined by NMR | 4 pages, submitted to Proceedings of SCES'07 | Physics B, 403, 986-989 (2008) | 10.1016/j.physb.2007.10.074 | null | cond-mat.str-el cond-mat.supr-con | null | We report ^{115}In nuclear magnetic resonance (NMR) measurements in the
heavy-fermion superconductor CeCoIn_5 as a function of temperature in different
magnetic fields applied parallel to the $(\hat a, \hat b)$ plane. The
measurements probe a part of the phase diagram in the vicinity of the
superconducting critical field H_{c2} where a possible inhomogeneous
superconducting state, Fulde-Ferrel-Larkin-Ovchinnikov (FFLO), is stabilized.
We have identified clear NMR signatures of two phase transitions occurring in
this part of the phase diagram. The first order phase transitions are
characterized by the sizable discontinuity of the shift. We find that a
continuous second order phase transition from the superconducting to the FFLO
state occurs at temperature below which the shift becomes temperature
independent. We have compiled the first phase diagram of CeCoIn_5 in the
vicinity of H_{c2} from NMR data and found that it is in agreement with the one
determined by thermodynamic measurements.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:42:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mitrović",
"V. F.",
""
],
[
"Koutroulakis",
"G.",
""
],
[
"Vachon",
"M. -A.",
""
],
[
"Horvatić",
"M.",
""
],
[
"Berthier",
"C.",
""
],
[
"Lapertot",
"G.",
""
],
[
"Flouquet",
"J.",
""
]
] |
0707.4158 | Daniel Braun | Daniel Braun and John Martin | Spontaneous emission from a two--level atom tunneling in a double--well
potential | 24 pages, 4 figures; improved discussion on the limitations of the
theory | Phys. Rev. A 77, 032102 (2008) | 10.1103/PhysRevA.77.032102 | null | quant-ph | null | We study a two-level atom in a double--well potential coupled to a continuum
of electromagnetic modes (black body radiation in three dimensions at zero
absolute temperature). Internal and external degrees of the atom couple due to
recoil during emission of a photon. We provide a full analysis of the problem
in the long wavelengths limit up to the border of the Lamb-Dicke regime,
including a study of the internal dynamics of the atom (spontaneous emission),
the tunneling motion, and the electric field of the emitted photon. The
tunneling process itself may or may not decohere depending on the wavelength
corresponding to the internal transition compared to the distance between the
two wells of the external potential, as well as on the spontaneous emission
rate compared to the tunneling frequency. Interference fringes appear in the
emitted light from a tunneling atom, or an atom in a stationary coherent
superposition of its center--of--mass motion, if the wavelength is comparable
to the well separation, but only if the external state of the atom is
post-selected.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 17:53:49 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 13:08:35 GMT"
}
] | 2008-03-11T00:00:00 | [
[
"Braun",
"Daniel",
""
],
[
"Martin",
"John",
""
]
] |
0707.4159 | Benny Sudakov | Jacob Fox and Benny Sudakov | Density theorems for bipartite graphs and related Ramsey-type results | null | null | null | null | math.CO | null | In this paper, we present several density-type theorems which show how to
find a copy of a sparse bipartite graph in a graph of positive density. Our
results imply several new bounds for classical problems in graph Ramsey theory
and improve and generalize earlier results of various researchers. The proofs
combine probabilistic arguments with some combinatorial ideas. In addition,
these techniques can be used to study properties of graphs with a forbidden
induced subgraph, edge intersection patterns in topological graphs, and to
obtain several other Ramsey-type statements.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:06:59 GMT"
},
{
"version": "v2",
"created": "Sun, 11 Nov 2007 22:57:21 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Fox",
"Jacob",
""
],
[
"Sudakov",
"Benny",
""
]
] |
0707.4160 | Alessandro D'Andrea | Alessandro D'Andrea | Finite vertex algebras and nilpotence | 24 pages | Journal of Pure and Applied Algebra 212 (4), 669-688 (2008) | 10.1016/j.jpaa.2007.06.020 | null | math.QA | null | I show that simple finite vertex algebras are commutative, and that the Lie
conformal algebra structure underlying a reduced (i.e., without nilpotent
elements) finite vertex algebra is nilpotent.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:32:23 GMT"
}
] | 2012-10-19T00:00:00 | [
[
"D'Andrea",
"Alessandro",
""
]
] |
0707.4161 | J. Marvin Herndon | J. Marvin Herndon | Magnetic Field Generation in Planets and Satellites by Natural Nuclear
Fission Reactors | expanded Fig. 4 and Table 1 | null | null | null | physics.geo-ph physics.gen-ph physics.space-ph | null | One of the most fundamental problems in physics has been to understand the
nature of the mechanism that generates the geomagnetic field and the magnetic
fields of other planets and satellites. For decades, the dynamo mechanism,
thought to be responsible for generating the geomagnetic field and other
planetary magnetic fields, has been ascribed to convection in each planet's
iron-alloy core. Recently, I described the problems inherent in Earth-core
convection and proposed instead that the geomagnetic field is produced by a
dynamo mechanism involving convection, not in the fluid core, but in the
electrically conductive, fluid, fission-product sub-shell of a natural nuclear
fission reactor at the center of the Earth, called the georeactor. Here I set
forth in detail the commonality in the Solar System of the matter like that of
the inside of the Earth, which is my basis for generalizing the concept of
planetary magnetic field generation by natural planetocentric nuclear fission
reactors.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:16:15 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jul 2007 17:19:30 GMT"
},
{
"version": "v3",
"created": "Tue, 28 Aug 2007 20:49:19 GMT"
},
{
"version": "v4",
"created": "Thu, 27 Sep 2007 16:17:48 GMT"
}
] | 2007-09-27T00:00:00 | [
[
"Herndon",
"J. Marvin",
""
]
] |
0707.4162 | Jozef Dudek | J.J. Dudek, R.G. Edwards, N. Mathur and D.G. Richards | Charmonium excited state spectrum in lattice QCD | Fixed typos: normalisation of chi-squared, some operator projections
in appendix, missing lattice irrep table | Phys.Rev.D77:034501,2008 | 10.1103/PhysRevD.77.034501 | JLAB-THY-07-689 | hep-lat hep-ph | null | Working with a large basis of covariant derivative-based meson interpolating
fields we demonstrate the feasibility of reliably extracting multiple excited
states using a variational method. The study is performed on quenched
anisotropic lattices with clover quarks at the charm mass. We demonstrate how a
knowledge of the continuum limit of a lattice interpolating field can give
additional spin-assignment information, even at a single lattice spacing, via
the overlap factors of interpolating field and state. Excited state masses are
systematically high with respect to quark potential model predictions and,
where they exist, experimental states. We conclude that this is most likely a
result of the quenched approximation.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:24:48 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 13:10:59 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Dudek",
"J. J.",
""
],
[
"Edwards",
"R. G.",
""
],
[
"Mathur",
"N.",
""
],
[
"Richards",
"D. G.",
""
]
] |
0707.4163 | Erasmo Ferreira | Erasmo Ferreira and Flavio Pereira | Amplitudes in pp and p-pbar scattering | 5 pages, 7 figures | Int.J.Mod.Phys.E16:2889-2892,2007 | 10.1142/S0218301307008410 | null | hep-ph | null | Solutions for the amplitudes that give accurate description of pp and p-pbar
scattering at high energies are investigated, with particular attention given
to the properties of their zeros and slopes, whose determination is required
for the study of the Coulomb interference region. Proper extrapolations of
these quantities to the LHC energies are important for the analysis of the
forthcoming experiments.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 18:39:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ferreira",
"Erasmo",
""
],
[
"Pereira",
"Flavio",
""
]
] |
0707.4164 | Frederick W. Strauch | Frederick W. Strauch | Any-order propagation of the nonlinear Schroedinger equation | 10 pages, no figures, submitted to Phys. Rev. E | null | 10.1103/PhysRevE.76.046701 | null | quant-ph | null | We derive an exact propagation scheme for nonlinear Schroedinger equations.
This scheme is entirely analogous to the propagation of linear Schroedinger
equations. We accomplish this by defining a special operator whose algebraic
properties ensure the correct propagation. As applications, we provide a simple
proof of a recent conjecture regarding higher-order integrators for the
Gross-Pitaevskii equation, extend it to multi-component equations, and to a new
class of integrators.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 19:02:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Strauch",
"Frederick W.",
""
]
] |
0707.4165 | Benne W. Holwerda | B. W. Holwerda, B. Draine, K.D. Gordon, R. A. Gonzalez, D. Calzetti,
M. Thornley, B. Buckalew, Ronald J. Allen and P. C. van der Kruit | The Opacity of Spiral Galaxy Disks VIII: Structure of the Cold ISM | 31 pages, 5 figures, 4 tables, accepted for publication in AJ | Astron.J.134:2226-2235,2007 | 10.1086/522230 | null | astro-ph | null | The quantity of dust in a spiral disk can be estimated using the dust's
typical emission or the extinction of a known source. In this paper, we compare
two techniques, one based on emission and one on absorption, applied on
sections of fourteen disk galaxies. The two measurements reflect, respectively
the average and apparent optical depth of a disk section. Hence, they depend
differently on the average number and optical depth of ISM structures in the
disk. The small scale geometry of the cold ISM is critical for accurate models
of the overall energy budget of spiral disks. ISM geometry, relative
contributions of different stellar populations and dust emissivity are all free
parameters in galaxy Spectral Energy Distribution (SED) models; they are also
sometimes degenerate, depending on wavelength coverage. Our aim is to constrain
typical ISM geometry. The apparent optical depth measurement comes from the
number of distant galaxies seen in HST images through the foreground disk. We
measure the IR flux in images from the {\it Spitzer} Infrared Nearby Galaxy
Survey in the same section of the disk that was covered by HST. A physical
model of the dust is fit to the SED to estimate the dust surface density, mean
temperature, and brightness in these disk sections. The surface density is
subsequently converted into the average optical depth estimate. The two
measurements generally agree. The ratios between the measured average and
apparent optical depths of the disk sections imply optically thin clouds in
these disks. Optically thick disks, are likely to have more than a single cloud
along the line-of-sight.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 19:29:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Holwerda",
"B. W.",
""
],
[
"Draine",
"B.",
""
],
[
"Gordon",
"K. D.",
""
],
[
"Gonzalez",
"R. A.",
""
],
[
"Calzetti",
"D.",
""
],
[
"Thornley",
"M.",
""
],
[
"Buckalew",
"B.",
""
],
[
"Allen",
"Ronald J.",
""
],
[
"van der Kruit",
"P. C.",
""
]
] |
0707.4166 | Todd Veldhuizen | Todd L. Veldhuizen | Parsimony Principles for Software Components and Metalanguages | Generative Programming and Component Engineering 2007 | null | null | null | cs.SE | null | Software is a communication system. The usual topic of communication is
program behavior, as encoded by programs. Domain-specific libraries are
codebooks, domain-specific languages are coding schemes, and so forth. To turn
metaphor into method, we adapt toolsfrom information theory--the study of
efficient communication--to probe the efficiency with which languages and
libraries let us communicate programs. In previous work we developed an
information-theoretic analysis of software reuse in problem domains. This new
paper uses information theory to analyze tradeoffs in the design of components,
generators, and metalanguages. We seek answers to two questions: (1) How can we
judge whether a component is over- or under-generalized? Drawing on minimum
description length principles, we propose that the best component yields the
most succinct representation of the use cases. (2) If we view a programming
language as an assemblage of metalanguages, each providing a complementary
style of abstraction, how can these metalanguages aid or hinder us in
efficiently describing software? We describe a complex triangle of interactions
between the power of an abstraction mechanism, the amount of reuse it enables,
and the cognitive difficulty of its use.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 19:29:29 GMT"
}
] | 2007-07-30T00:00:00 | [
[
"Veldhuizen",
"Todd L.",
""
]
] |
0707.4167 | Benne W. Holwerda | B. W. Holwerda, M. Meyer, M. Regan, D. Calzetti, K. D. Gordon, J. D.
Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B.
Buckalew, R. C. Kennicutt and R. A. Gonzalez | Gaps in the cloud cover? Comparing extinction measures in spiral disks | 22 pages, 2 figures, 3 tables, accepted for publication in AJ | Astron.J.134:1655-1661,2007 | 10.1086/521824 | null | astro-ph | null | Dust in galaxies can be mapped by either the FIR/sub-mm emission, the optical
or infrared reddening of starlight, or the extinction of a known background
source. We compare two dust extinction measurements for a set of fifteen
sections in thirteen nearby galaxies, to determine the scale of the dusty ISM
responsible for disk opacity: one using stellar reddening and the other a known
background source. In our earlier papers, we presented extinction measurements
of 29 galaxies, based on calibrated counts of distant background objects
identified though foreground disks in HST/WFPC2 images. For the 13 galaxies
that overlap with the Spitzer Infrared Nearby Galaxies Survey (SINGS), we now
compare these results with those obtained from an I-L color map. Our goal is to
determine whether or not a detected distant galaxy indicates a gap in the dusty
ISM, and hence to better understand the nature and geometry of the disk
extinction.
We find that distant galaxies are predominantly in low-extinction sections
marked by the color maps, indicating that their number depends both on the
cloud cover of {\it Spitzer}-resolved dust structures --mostly the spiral
arms--and a diffuse, unresolved underlying disk. We note that our infrared
color map (E[I-L]) underestimates the overall dust presence in these disks
severely, because it implicitly assumes the presence of a dust screen in front
of the stellar distribution.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 19:40:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Holwerda",
"B. W.",
""
],
[
"Meyer",
"M.",
""
],
[
"Regan",
"M.",
""
],
[
"Calzetti",
"D.",
""
],
[
"Gordon",
"K. D.",
""
],
[
"Smith",
"J. D.",
""
],
[
"Dale",
"D.",
""
],
[
"Engelbracht",
"C. W.",
""
],
[
"Jarrett",
"T.",
""
],
[
"Thornley",
"M.",
""
],
[
"Bot",
"C.",
""
],
[
"Buckalew",
"B.",
""
],
[
"Kennicutt",
"R. C.",
""
],
[
"Gonzalez",
"R. A.",
""
]
] |
0707.4168 | Chun-Sheng An | Chun-Sheng An | The $qqqq\bar{q}$ components and the magnetic moments of the charmed and
the bottomed baryons | Some references added, and typos corrected | Nucl.Phys.A797:131-144,2007; Erratum-ibid.A801:82,2008 | 10.1016/j.nuclphysa.2007.10.002 10.1016/j.nuclphysa.2007.12.002 | null | hep-ph | null | We give the explicit wave functions of the $qqqq\bar{q}$ components of the
C=+1, J=1/2 charmed baryons, $\Sigma_{c}$, $\Lambda_{c}$ and $\Xi_{c}^{a}$, and
calculate the magnetic moments by adding the 5q components contributions, and
we also compute the magnetic moments of the $\Sigma_{b}$ and $\Sigma_{b}^{*}$
baryons. The influence of the additional light and strange $q\bar{q}$ pairs is
investigated. It's obvious that the constituent quark masses of the charm and
beauty quarks are much heavier than that of the light and strange quarks,
consequently, the hidden flavor contributions to the baryons magnetic moments
may be significant. What is interesting is that the inclusion of the
$qqqq\bar{q}$ components contributions leads to different $\Lambda^{+}_{c}$,
$\Xi^{a+}_{c}$ and $\Xi^{a0}_{c}$ magnetic moments, all of which are predicted
to be the same value $0.38\mu_{N}$ on the basis of the classical qqq quark
model. And it's shown that the differences of these magnetic moments are
independent of the constituent mass of the charm quark.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 14:41:03 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 15:35:43 GMT"
},
{
"version": "v3",
"created": "Tue, 27 Nov 2007 04:49:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"An",
"Chun-Sheng",
""
]
] |
0707.4169 | Don N. Page | Don N. Page | Typicality Defended | 7 pages, LaTeX | null | null | Alberta-Thy-10-07 | hep-th | null | Hartle and Srednicki have argued that there is no observational evidence
favoring our typicality. Here it is shown that such evidence does arise from
including the `normalization principle' requirement that the sum of the
likelihoods for all possible observations is normalized to unity in each
theory.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:46:28 GMT"
}
] | 2015-07-24T00:00:00 | [
[
"Page",
"Don N.",
""
]
] |
0707.4170 | Raul Jimenez | Francesco de Bernardis (Rome), Alessandro Melchiorri (Rome), Licia
Verde (ICE & Princeton), Raul Jimenez (ICE & Princeton) | The Cosmic Neutrino Background and the Age of the Universe | JCAP, in press | JCAP0803:020,2008 | 10.1088/1475-7516/2008/03/020 | null | astro-ph hep-ph | null | We discuss the cosmological degeneracy between the age of the Universe, the
Hubble parameter and the effective number of relativistic particles N_eff. We
show that independent determinations of the Hubble parameter H(z) as those
recently provided by Simon,Verde, Jimenez (2006), combined with other
cosmological data sets can provide the most stringent constraint on N_eff,
yielding N_eff=3.7 (-1.2) (+1.1) at 95% confidence level. A neutrino background
is detected with high significance: N_eff >1.8 at better than 99% confidence
level. Constraints on the age of the universe in the framework of an extra
background of relativistic particles are improved by a factor 3.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:00:11 GMT"
},
{
"version": "v2",
"created": "Sat, 8 Mar 2008 14:27:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"de Bernardis",
"Francesco",
"",
"Rome"
],
[
"Melchiorri",
"Alessandro",
"",
"Rome"
],
[
"Verde",
"Licia",
"",
"ICE & Princeton"
],
[
"Jimenez",
"Raul",
"",
"ICE & Princeton"
]
] |
0707.4171 | Igor Herbut | Igor F. Herbut, Vladimir Juricic, and Oskar Vafek | Coulomb interaction, ripples, and the minimal conductivity of graphene | 4 revtex pages, 2 figures; published version | Phys. Rev. Lett. 100 (2008) 046403 | 10.1103/PhysRevLett.100.046403 | null | cond-mat.mes-hall cond-mat.str-el | null | We argue that the unscreened Coulomb interaction in graphene provides a
positive, universal, and logarithmic correction to scaling of zero-temperature
conductivity with frequency. The combined effect of the disorder due to
wrinkling of the graphene sheet and the long range electron-electron
interactions is a finite positive contribution to the dc conductivity. This
contribution is disorder strength dependent and thus non-universal. The
low-energy behavior of such a system is governed by the line of fixed points at
which both the interaction and disorder are finite, and the density of states
is exactly linear. An estimate of the typical random vector potential
representing ripples in graphene brings the theoretical value of the minimal
conductivity into the vicinity of 4e^2/h.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:38:17 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Jan 2008 20:45:54 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Herbut",
"Igor F.",
""
],
[
"Juricic",
"Vladimir",
""
],
[
"Vafek",
"Oskar",
""
]
] |
0707.4172 | Adrian E. Feiguin | A.E. Feiguin, and F. Heidrich-Meisner | Pairing states of a polarized Fermi gas trapped in a one-dimensional
optical lattice | 4 pages, 5 figs | Phys. Rev. B 76, 220508(R) (2007) | 10.1103/PhysRevB.76.220508 | null | cond-mat.str-el cond-mat.supr-con | null | We study the properties of a one-dimensional (1D) gas of fermions trapped in
a lattice by means of the density matrix renormalization group method, focusing
on the case of unequal spin populations, and strong attractive interaction. In
the low density regime, the system phase-separates into a well defined
superconducting core and a fully polarized metallic cloud surrounding it. We
argue that the superconducting phase corresponds to a 1D analogue of the
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, with a quasi-condensate of
tightly bound bosonic pairs with a finite center-of-mass momentum that scales
linearly with the magnetization. In the large density limit, the system allows
for four phases: in the core, we either find a Fock state of localized pairs or
a metallic shell with free spin-down fermions moving in a fully filled
background of spin-up fermions. As the magnetization increases, the Fock state
disappears to give room for a metallic phase, with a partially polarized
superconducting FFLO shell and a fully polarized metallic cloud surrounding the
core.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:51:27 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 18:38:26 GMT"
},
{
"version": "v3",
"created": "Fri, 3 Aug 2007 05:37:45 GMT"
},
{
"version": "v4",
"created": "Wed, 2 Jan 2008 17:48:26 GMT"
}
] | 2008-01-02T00:00:00 | [
[
"Feiguin",
"A. E.",
""
],
[
"Heidrich-Meisner",
"F.",
""
]
] |
0707.4173 | Sean Moran | Sean M. Moran, Richard S. Ellis, Tommaso Treu, Graham P. Smith, R.
Michael Rich, Ian Smail | A Wide-field Survey of Two Z~0.5 Galaxy Clusters: Identifying the
Physical Processes Responsible for the Observed Transformation of Spirals
into S0s | 21 pages, 12 Figures, Accepted to ApJ | null | 10.1086/522303 | null | astro-ph | null | We present new results from our comprehensive comparative survey of two
massive, intermediate redshift galaxy clusters, Cl0024+17 (z=0.39) and
MS0451-03 (z=0.54). We identify and study several key classes of `transition
objects' whose stellar populations or dynamical states indicate a recent or
ongoing change in morphology and star formation rate. For the first time, we
have been able to conclusively identify spiral galaxies in the process of
transforming into S0 galaxies. This has been accomplished by locating both
spirals whose star formation is being quenched as well as their eventual
successors, the recently created S0s. Differences between the two clusters in
both the timescales and spatial location of this conversion process allow us to
evaluate the relative importance of several proposed physical mechanisms that
could be responsible for the transformation. Combined with other diagnostics
that are sensitive to either ICM-driven galaxy evolution or galaxy-galaxy
interactions, we describe a self-consistent picture of galaxy evolution in
clusters. We find that spiral galaxies within infalling groups have already
begun a slow process of conversion into S0s primarily via gentle galaxy-galaxy
interactions. The fates of spirals upon reaching the core of the cluster depend
heavily on the cluster ICM, with rapid conversion of all remaining spirals into
S0s via ram-pressure stripping in clusters where the ICM is dense. In the
presence of a less-dense ICM, the conversion continues at a slower pace, with
galaxy-galaxy interactions continuing to play a role along with `starvation' by
the ICM. We conclude that the buildup of the local S0 population through the
transformation of spiral galaxies is a heterogeneous process that nevertheless
proceeds robustly across a variety of different environments.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:01:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Moran",
"Sean M.",
""
],
[
"Ellis",
"Richard S.",
""
],
[
"Treu",
"Tommaso",
""
],
[
"Smith",
"Graham P.",
""
],
[
"Rich",
"R. Michael",
""
],
[
"Smail",
"Ian",
""
]
] |
0707.4174 | Razvan Radulescu M.D. | Razvan Tudor Radulescu | Retinoblastoma protein is the likely common effector for distinct
anti-aging pathways | 4 pages | null | null | null | q-bio.SC q-bio.BM | null | The multiple worlds of genetically manipulated laboratory organisms such as
transgenic mice or worms with certain gene mutations are somewhat reminiscent
of parallel worlds in quantum mechanics. So are various models of aging tested
in such organisms. In this context, the tumor suppressor p53 has been found to
either accelerate or delay aging, the latter, for instance, in conjunction with
ARF, another tumor suppressor, as shown very recently. To more easily determine
which of these artificial settings comes closest to real life, I discuss here
their features in the light of my protein structure-based insights that have
led me to propose a physiological anti-aging role for the retinoblastoma tumor
suppressor protein (RB) over the past four years.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:05:18 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Radulescu",
"Razvan Tudor",
""
]
] |
0707.4175 | Teodor Banica | Teodor Banica, Jean-Marc Schlenker | On Hadamard matrices at roots of unity | This paper has been withdrawn by the authors, the main result being
known since Lam and Leung, J. Algebra 2000 | null | null | null | math.CO | null | This paper has been withdrawn by the authors, the main result being known
since Lam and Leung, J. Algebra 2000.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:05:57 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Dec 2007 00:21:40 GMT"
},
{
"version": "v3",
"created": "Tue, 29 Jan 2013 15:57:26 GMT"
}
] | 2013-01-30T00:00:00 | [
[
"Banica",
"Teodor",
""
],
[
"Schlenker",
"Jean-Marc",
""
]
] |
0707.4176 | Thaisa Storchi Bergmann | Thaisa Storchi-Bergmann, Oli L. Dors Jr. and Rogemar A. Riffel
(IF-UFRGS, Brazil), Kambiz Fathi (IAC, Spain), David J. Axon and Andrew
Robinson (RIT), Alessandro Marconi (Arcetri, Italy) and Goran Ostlin
(Stockholm Observatory, Sweden) | Nuclear spirals as feeding channels to the Supermassive Black Hole: the
case of the galaxy NGC 6951 | 25 pages, 6 eps figures, accepted for publication in ApJ | null | 10.1086/521918 | null | astro-ph | null | We report the discovery of gas streaming motions along nuclear spiral arms
towards the LINER nucleus of the galaxy NGC 6951. The observations, obtained
using the GMOS integral field spectrograph on the Gemini North telescope,
yielded maps of the flux distributions and gas kinematics in the Halpha,
[NII]6584 and [SII]6717,31 emission lines of the inner 7x5 arcsec^2 of the
galaxy. This region includes a circumnuclear star-forming ring with radius
500pc, a nuclear spiral inside the ring and the LINER nucleus. The kinematics
of the ionized gas is dominated by rotation, but subtraction of a kinematic
model of a rotating exponential disk reveals deviations from circular rotation
within the nuclear ring which can be attributed to (1) streaming motions along
the nuclear spiral arms and (2) a bipolar outflow which seems to be associated
to a nuclear jet. On the basis of the observed streaming velocities and
geometry of the spiral arms we estimate a mass inflow rate of ionized gas of
3x10^(-4) Msun/yr, which is of the order of the accretion rate necessary to
power the LINER nucleus of NGC 6951. Similar streaming motions towards the
nucleus of another galaxy with LINER nucleus -- NGC 1097 -- have been reported
by our group in a previous paper. Taken together, these results support a
scenario in which nuclear spirals are channels through which matter is
transferred from galactic scales to the nuclear region to feed the supermassive
black hole.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:07:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Storchi-Bergmann",
"Thaisa",
"",
"IF-UFRGS, Brazil"
],
[
"Dors",
"Oli L.",
"Jr.",
"IF-UFRGS, Brazil"
],
[
"Riffel",
"Rogemar A.",
"",
"IF-UFRGS, Brazil"
],
[
"Fathi",
"Kambiz",
"",
"IAC, Spain"
],
[
"Axon",
"David J.",
"",
"RIT"
],
[
"Robinson",
"Andrew",
"",
"RIT"
],
[
"Marconi",
"Alessandro",
"",
"Arcetri, Italy"
],
[
"Ostlin",
"Goran",
"",
"Stockholm Observatory, Sweden"
]
] |
0707.4177 | Kenneth Burch | K.S. Burch, Elbert E.M. Chia, D. Talbayev, B.C. Sales, D. Mandrus,
A.J. Taylor, R.D. Averitt | Coupling Between An Optical Phonon and the Kondo Effect | 4 Pages, 3 Figures, submitted to Phys. Rev. Lett | null | 10.1103/PhysRevLett.100.026409 | null | cond-mat.str-el | null | We explore the ultra-fast optical response of Yb_{14}MnSb_{11}, providing
further evidence that this Zintl compound is the first ferromagnetic,
under-screened Kondo lattice. These experiments also provide the first
demonstration of coupling between an optical phonon mode and the Kondo effect.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:18:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Burch",
"K. S.",
""
],
[
"Chia",
"Elbert E. M.",
""
],
[
"Talbayev",
"D.",
""
],
[
"Sales",
"B. C.",
""
],
[
"Mandrus",
"D.",
""
],
[
"Taylor",
"A. J.",
""
],
[
"Averitt",
"R. D.",
""
]
] |
0707.4178 | Douglas J. Durian | A.R. Abate and D.J. Durian | Topological persistence and dynamical heterogeneities near jamming | null | Phys. Rev. E 76, 021306/1-9 (2007) | 10.1103/PhysRevE.76.021306 | null | cond-mat.soft | null | We introduce topological methods for quantifying spatially heterogeneous
dynamics, and use these tools to analyze particle-tracking data for a
quasi-two-dimensional granular system of air-fluidized beads on approach to
jamming. In particular we define two overlap order parameters, which quantify
the correlation between particle configurations at different times, based on a
Voronoi construction and the persistence in the resulting cells and nearest
neighbors. Temporal fluctuations in the decay of the persistent area and bond
order parameters define two alternative dynamic four-point susceptibilities,
XA(t) and XB(t), well-suited for characterizing spatially-heterogeneous
dynamics. These are analogous to the standard four-point dynamic susceptibility
X4(l,t), but where the space-dependence is fixed uniquely by topology rather
than by discretionary choice of cutoff function. While these three
susceptibilities yield characteristic time scales that are somewhat different,
they give domain sizes for the dynamical heterogeneities that are in good
agreement and that diverge on approach to jamming.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 16:18:10 GMT"
}
] | 2007-08-30T00:00:00 | [
[
"Abate",
"A. R.",
""
],
[
"Durian",
"D. J.",
""
]
] |
0707.4179 | Marco Peloso | A.E. Gumrukcuoglu, Carlo R. Contaldi, Marco Peloso | Inflationary perturbations in anisotropic backgrounds and their imprint
on the CMB | 31 pages, 3 figures | JCAP0711:005,2007 | 10.1088/1475-7516/2007/11/005 | UMN-TH-2614/07, Imperial/TP/CRC/02 | astro-ph gr-qc hep-ph hep-th | null | We extend the standard theory of cosmological perturbations to homogeneous
but anisotropic universes. We present an exhaustive computation for the case of
a Bianchi I model, with a residual isotropy between two spatial dimensions,
which is undergoing complete isotropization at the onset of inflation; we also
show how the computation can be further extended to more general backgrounds.
In presence of a single inflaton field, there are three physical perturbations
(precisely as in the isotropic case), which are obtained (i) by removing gauge
and nondynamical degrees of freedom, and (ii) by finding the combinations of
the remaining modes in terms of which the quadratic action of the perturbations
is canonical. The three perturbations, which later in the isotropic regime
become a scalar mode and two tensor polarizations (gravitational wave), are
coupled to each other already at the linearized level during the anisotropic
phase. This generates nonvanishing correlations between different modes of the
CMB anisotropies, which can be particularly relevant at large scales (and,
potentially, be related to the large scale anomalies in the WMAP data). As an
example, we compute the spectrum of the perturbations in this Bianchi I
geometry, assuming that the inflaton is in a slow roll regime also in the
anisotropic phase. For this simple set-up, fixing the initial conditions for
the perturbations appears more difficult than in the standard case, and
additional assumptions seem to be needed to provide predictions for the CMB
anisotropies.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:41:49 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Nov 2007 22:17:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gumrukcuoglu",
"A. E.",
""
],
[
"Contaldi",
"Carlo R.",
""
],
[
"Peloso",
"Marco",
""
]
] |
0707.4180 | Richard Harley | W.J.H. Leyland, R.T. Harley, M. Henini, D. Taylor, A.J. Shields, I.
Farrer and D.A. Ritchie | Oscillatory D'yakonov-Perel' spin dynamics in two dimensional electron
gases | null | null | 10.1103/PhysRevB.76.195305 | null | cond-mat.other | null | Optical pump-probe measurements of spin-dynamics at temperatures down to 1.5K
are described for a series of (001)-oriented GaAs/AlGaAs quantum well samples
containing high mobility two-dimensional electron gases (2DEGs). For well
widths ranging from 5 nm to 20 nm and 2DEG sheet densities from 1.75x1011cm-2
to 3.5x1011cm-2 the evolution of a small injected spin population is found to
be a damped oscillation rather than exponential relaxation, consistent with the
quasi-collision-free regime of D'yakonov-Perel spin dynamics. A Monte Carlo
simulation method is used to extract the spin-orbit-induced electron spin
precession frequency |W(kF)| and electron momentum scattering time tp* at the
Fermi wavevector. The spin decay time passes through a minimum at a temperature
corresponding to the transition from collision-free to collision-dominated
regimes and tp* is found to be close to the ensemble momentum scattering time
tp obtained from Hall measurements of electron mobility. The values of |W(kF)|
give the Dresselhaus (BIA) coefficient of spin-orbit interaction as a function
of electron confinement energy in the quantum show, qualitatively, the
behaviour expected from k.p theory.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:37:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Leyland",
"W. J. H.",
""
],
[
"Harley",
"R. T.",
""
],
[
"Henini",
"M.",
""
],
[
"Taylor",
"D.",
""
],
[
"Shields",
"A. J.",
""
],
[
"Farrer",
"I.",
""
],
[
"Ritchie",
"D. A.",
""
]
] |
0707.4181 | Hassan Firouzjahi | Robert Brandenberger, Hassan Firouzjahi and Omid Saremi | Cosmological Perturbations on a Bouncing Brane | 30 pages, 8 figures, typos corrected | null | 10.1088/1475-7516/2007/11/028 | null | hep-th astro-ph gr-qc hep-ph | null | The cosmological perturbations on a bouncing brane are studied. The brane is
moving inside a Klebanov-Strassler throat where the infra-red region of the
geometry is smoothly cut off. For an observer confined to the world-volume of
the brane, this results in a non-singular bouncing mirage cosmology. We have
calculated the scalar perturbations corresponding to the normal displacements
of the brane. This is performed in the probe brane limit where the
gravitational back-reaction of the brane on the bulk throat is absent. Our
model provides a framework for studying the transfer of fluctuations from a
contracting to an expanding phase. We find that the spectral index of the
dominant mode of the metric fluctuation is un-changed, unlike what is obtained
by gluing contracting to expanding Einstein universes with the help of the
usual matching conditions. Assuming that the fluctuations start off in a vacuum
state on sub-Hubble scales during the contracting phase, it is shown that the
resulting spectral index n_s on super-Hubble scales in the expanding phase has
a large blue tilt. When the brane is moving slowly inside the throat and its
kinetic energy is negligible compared to its rest mass, one finds n_s=3. For a
fast-rolling brane with a large kinetic energy, the spectral index is n_s =
2.3. This may put severe constraints on models of mirage cosmology.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 02:47:57 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 17:37:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Brandenberger",
"Robert",
""
],
[
"Firouzjahi",
"Hassan",
""
],
[
"Saremi",
"Omid",
""
]
] |
0707.4182 | James E. Rhoads | Steve Dawson, James E. Rhoads, Sangeeta Malhotra, Daniel Stern,
JunXian Wang, Arjun Dey, Hyron Spinrad, and Buell T. Jannuzi | A Luminosity Function of Lyman Alpha Emitting Galaxies at Redshift 4.5 | 36 pages, 10 figures; resubmitted to The Astrophysical Journal (after
one round of referee's comments) | null | 10.1086/522908 | null | astro-ph | null | We present a catalog of 59 z=4.5 Lyman alpha emitting galaxies
spectroscopically confirmed in a campaign of Keck/DEIMOS follow-up observations
to candidates selected in the Large Area Lyman Alpha (LALA) narrow-band imaging
survey. We targeted 97 candidates for spectroscopic follow-up; by accounting
for the variety of conditions under which we performed spectroscopy, we
estimate a selection reliability of about 76%. Together with our previous
sample of Keck/LRIS confirmations, the 59 sources confirmed herein bring the
total catalog to 73 spectroscopically confirmed z=4.5 Lyman alpha emitting
galaxies in the 0.7 square degrees covered by the LALA imaging. As with the
Keck/LRIS sample, we find that a non-negligible fraction of the confirmed Lyman
alpha lines have rest-frame equivalent widths (w_{rest}) which exceed the
maximum predicted for normal stellar populations: 17% -- 31% (93% confidence)
of the detected galaxies show w_{rest} > 190 AA, and 12% -- 27% (90%
confidence) show w_{rest} > 240 AA. We construct a luminosity function of z=4.5
Lyman alpha emission lines for comparison to Lyman alpha luminosity functions
spanning 3.1 < z < 6.6. We find no significant evidence for Lyman alpha
luminosity function evolution from z ~ 3 to z ~ 6. This result supports the
conclusion that the intergalactic medium remains largely reionized from the
local universe out to z=6.5. It is somewhat at odds with the pronounced drop in
the cosmic star formation rate density recently measured between z~3 and z~6 in
continuum-selected Lyman-break galaxies, and therefore potentially sheds light
on the relationship between the two populations.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 20:39:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dawson",
"Steve",
""
],
[
"Rhoads",
"James E.",
""
],
[
"Malhotra",
"Sangeeta",
""
],
[
"Stern",
"Daniel",
""
],
[
"Wang",
"JunXian",
""
],
[
"Dey",
"Arjun",
""
],
[
"Spinrad",
"Hyron",
""
],
[
"Jannuzi",
"Buell T.",
""
]
] |
0707.4183 | Sei-Hoon Moon | J.H. Kim, Sei-Hoon Moon | Electric Charge in Interaction with Magnetically Charged Black Holes | 26 pages, 4 figures ; Typos are corrected and a reference is added | JHEP0709:088,2007 | 10.1088/1126-6708/2007/09/088 | null | gr-qc | null | We examine the angular momentum of an electric charge e placed at rest
outside a dilaton black hole with magnetic charge Q. The electromagnetic
angular momentum which is stored in the electromagnetic field outside the black
hole shows several common features regardless of the dilaton coupling strength,
though the dilaton black holes are drastically different in their spacetime
structure depending on it. First, the electromagnetic angular momentum depends
on the separation distance between the two objects and changes monotonically
from eQ to 0 as the charge goes down from infinity to the horizon, if
rotational effects of the black hole are discarded. Next, as the black hole
approaches extremality, however, the electromagnetic angular momentum tends to
be independent of the distance between the two objects. It is then precisely
$eQ$ as in the electric charge and monopole system in flat spacetime. We
discuss why these effects are exhibited and argue that the above features are
to hold in widely generic settings including black hole solutions in theories
with more complicated field contents, by addressing the no hair theorem for
black holes and the phenomenon of field expulsion exhibited by extremal black
holes.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 15:31:51 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Oct 2007 19:48:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kim",
"J. H.",
""
],
[
"Moon",
"Sei-Hoon",
""
]
] |
0707.4184 | Edith Adan-Bante | Edith Adan-Bante | Restriction of characters and products of characters | 4 pages | null | null | null | math.GR | null | Let G be a finite p-group, for some prime p, and $\psi, \theta \in \Irr(G)$
be irreducible complex characters of G. It has been proved that if, in
addition, $\psi,\theta$ are faithful characters, then the product $\psi\theta$
is a multiple of an irreducible or it is the nontrivial linear combination of
at least $\frac{p+1}{2}$ distinct irreducible characters of G. We show that if
we do not require the characters to be faithful, then given any integer k>0, we
can always find a p-group G and irreducible characters $\Psi$ and $\Theta$ such
that $\Psi\Theta$ is the nontrivial combination of exactly k distinct
irreducible characters. We do this by translating examples of decompositions of
restrictions of characters into decompositions of products of characters.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:00:57 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Adan-Bante",
"Edith",
""
]
] |
0707.4185 | Tom Solomon | M. E. Schwartz and T. H. Solomon | Frozen fronts in cellular flows | 10 pages, 5 figures | null | null | null | nlin.PS | null | We present experiments on the behavior of reaction fronts in ordered and
disordered cellular flows with imposed winds. Fronts in a chain of alternating
vortices are found to freeze (pin to the separatrix) for a wide range of
imposed winds that grows nonlinearly with the characteristic strength of the
underlying vorticity. Experiments in spatially-disordered flows demonstrate
that freezing of fronts is common to cellular flows; furthermore, it is not
dependent on boundary conditions. We therefore anticipate similar pinning in a
wide range of cellular flows and front-producing systems.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:04:52 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Schwartz",
"M. E.",
""
],
[
"Solomon",
"T. H.",
""
]
] |
0707.4186 | Erasmo Ferreira | Erasmo Ferreira | Derivative Dispersion Relations for the Amplitude Slopes in pp and
p-pbar Scattering | 5 pages and 2 figures | Int.J.Mod.Phys.E16:2893-2897,2007 | 10.1142/S021830130700788X | null | hep-ph | null | We extend the use of derivative dispersion relations to the study of slopes
of the real and imaginary amplitudes in pp and p-pbar elastic scattering. The
new relations are tested against the solutions for the amplitudes obtained in
the analysis of the high energy data. Extensions beyond the forward direction
are investigated.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:09:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ferreira",
"Erasmo",
""
]
] |
0707.4187 | Douglas Galvao | Varlei Rodrigues, Fernando Sato, Douglas S. Galvao, and Daniel Ugarte | Is Small Perfect? Size Limit to Defect Formation in Pyramidal Pt
Nanocontacts | 4 pages, 3 figures | null | 10.1103/PhysRevLett.99.255501 | null | cond-mat.mtrl-sci | null | We report high resolution transmission electron microscopy and ab initio
calculation results for the defect formation in Pt nanocontacts (NCs). Our
results show that there is a size limit to the existence of twins (extended
structural defects). Defects are always present but blocked away from the tip
axes. The twins may act as scattering plane, influencing contact electron
transmission for Pt NC at room temperature and Ag/Au NC at low temperature.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:56:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rodrigues",
"Varlei",
""
],
[
"Sato",
"Fernando",
""
],
[
"Galvao",
"Douglas S.",
""
],
[
"Ugarte",
"Daniel",
""
]
] |
0707.4188 | Jeffrey Winicour | H.-O. Kreiss, O. Reula, O. Sarbach, J. Winicour | Well-posed initial-boundary value problem for the harmonic Einstein
equations using energy estimates | More explanatory material and title, as will appear in the published
article in Classical and Quantum Gravity | null | 10.1088/0264-9381/24/23/017 | null | gr-qc | null | In recent work, we used pseudo-differential theory to establish conditions
that the initial-boundary value problem for second order systems of wave
equations be strongly well-posed in a generalized sense. The applications
included the harmonic version of the Einstein equations. Here we show that
these results can also be obtained via standard energy estimates, thus
establishing strong well-posedness of the harmonic Einstein problem in the
classical sense.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 21:49:40 GMT"
},
{
"version": "v2",
"created": "Mon, 15 Oct 2007 15:58:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kreiss",
"H. -O.",
""
],
[
"Reula",
"O.",
""
],
[
"Sarbach",
"O.",
""
],
[
"Winicour",
"J.",
""
]
] |
0707.4189 | Kun Yang | Kun Yang | Superfluid-Insulator Transition and Fermion Pairing in Bose-Fermi
Mixtures | Expanded version as appeared in print | Phys. Rev. B 77, 085115 (2008) | 10.1103/PhysRevB.77.085115 | null | cond-mat.supr-con cond-mat.str-el | null | It is well known that bosons on an optical lattice undergo a second-order
superfluid-insulator transition (SIT) when the lattice potential increases. In
this paper we study SIT when fermions coexist with the bosons. We find that the
critical properties of particle-hole symmetric SIT with dynamical exponent z=1
is modified when fermions are present; it either becomes a fluctuation-driven
first order transition or a different second-order transition. On the other
hand the more generic particle-hole asymmetric (with z=2) SIT is stable against
coupling with fermions. We also discuss pairing interaction between fermions
mediated by quantum critical fluctuations near SIT.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 12:27:30 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Feb 2008 02:19:01 GMT"
}
] | 2008-02-20T00:00:00 | [
[
"Yang",
"Kun",
""
]
] |
0707.4190 | Vandana Desai | V. Desai, L. Armus, H. W. W. Spoon, V. Charmandaris, J. Bernard-Salas,
B. R. Brandl, D. Farrah, B. T. Soifer, H. I. Teplitz, P. M. Ogle, D. Devost,
S. J. U. Higdon, J. A. Marshall, J. R. Houck | PAH Emission from Ultraluminous Infrared Galaxies | 15 pages, 9 Figures; Accepted for publication in ApJ | null | 10.1086/522104 | null | astro-ph | null | We explore the relationships between the Polycyclic Aromatic Hydrocarbon
(PAH) feature strengths, mid-infrared continuum luminosities, far-infrared
spectral slopes, optical spectroscopic classifications, and silicate optical
depths within a sample of 107 ULIRGs observed with the Infrared Spectrograph on
the Spitzer Space Telescope. The detected 6.2 micron PAH equivalent widths
(EQWs) in the sample span more than two orders of magnitude (0.006-0.8 micron),
and ULIRGs with HII-like optical spectra or steep far-infrared spectral slopes
(S_{25} / S_{60} < 0.2) typically have 6.2 micron PAH EQWs that are half that
of lower-luminosity starbursts. A significant fraction (~40-60%) of HII-like,
LINER-like, and cold ULIRGs have very weak PAH EQWs. Many of these ULIRGs also
have large (tau_{9.7} > 2.3) silicate optical depths. The far-infrared spectral
slope is strongly correlated with PAH EQW, but not with silicate optical depth.
In addition, the PAH EQW decreases with increasing rest-frame 24 micron
luminosity. We argue that this trend results primarily from dilution of the PAH
EQW by continuum emission from dust heated by a compact central source,
probably an AGN. High luminosity, high-redshift sources studied with Spitzer
appear to have a much larger range in PAH EQW than seen in local ULIRGs, which
is consistent with extremely luminous starburst systems being absent at low
redshift, but present at early epochs.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 22:06:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Desai",
"V.",
""
],
[
"Armus",
"L.",
""
],
[
"Spoon",
"H. W. W.",
""
],
[
"Charmandaris",
"V.",
""
],
[
"Bernard-Salas",
"J.",
""
],
[
"Brandl",
"B. R.",
""
],
[
"Farrah",
"D.",
""
],
[
"Soifer",
"B. T.",
""
],
[
"Teplitz",
"H. I.",
""
],
[
"Ogle",
"P. M.",
""
],
[
"Devost",
"D.",
""
],
[
"Higdon",
"S. J. U.",
""
],
[
"Marshall",
"J. A.",
""
],
[
"Houck",
"J. R.",
""
]
] |
0707.4191 | Philip Amanik | Philip S. Amanik and Gail C. McLaughlin | Neutron Form Factor from Neutrino-Nucleus Coherent Elastic Scattering | 6 pages, 2 figures | null | null | null | hep-ph nucl-th | null | We analyze the prospect of measuring the neutron form factor of a nucleus
through the detection of neutrino-nucleus coherent elastic scattering. We
predict numbers of events in a liquid noble nuclear recoil detector at a
stopped pion neutrino source. We discuss the precision required to distinguish
between different theoretical models for the form factor.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 22:01:57 GMT"
}
] | 2007-08-13T00:00:00 | [
[
"Amanik",
"Philip S.",
""
],
[
"McLaughlin",
"Gail C.",
""
]
] |
0707.4192 | Anh-Thu Le | Anh-Thu Le, Toru Morishita, and C. D. Lin | Improved Lewenstein model for high-order harmonic generation of atoms
and molecules with scattering wavefunctions | 4 pages, 4 figures | null | null | null | physics.atom-ph | null | We demonstrate a simple method to improve the Lewenstein model for the
description of high-order harmonic generation (HHG). It is shown that HHG
spectra can be expressed as the product of a returning electron wave packet and
the photo-recombination cross sections, where the former can be extracted from
the Lewenstein model. By replacing plane waves with scattering waves in the
calculation of recombination matrix elements, we showed that the resulting HHG
spectra agree well with those from solving the time-dependent Schr\"odinger
equation. The improved model can be used for quantitative calculations of high
harmonics generated by molecules.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 22:13:51 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Le",
"Anh-Thu",
""
],
[
"Morishita",
"Toru",
""
],
[
"Lin",
"C. D.",
""
]
] |
0707.4193 | Sushil Shetty | Sushil Shetty, Xylar S. Asay-Davis, Philip S. Marcus | On the interaction of Jupiter's Great Red Spot and zonal jet streams | Manuscript accepted to Journal of the Atmospheric Sciences, March
2007. v2: minor stylistic changes (after journal proof reading) | Journal of Atmospheric Sciences, 2007, Vol. 64, pg. 4432_4444 | 10.1175/2007JAS2097.1 | null | physics.flu-dyn physics.ao-ph | null | In this paper, Jupiter's Great Red Spot (GRS) is used to determine properties
of the Jovian atmosphere that cannot otherwise be found. These properties
include the potential vorticity of the GRS and its neighboring jet streams, the
shear imposed on the GRS by the jet streams, and the vertical entropy gradient
(i.e., Rossby deformation radius). The cloud cover of the GRS, which is often
used to define the GRS's area and aspect ratio, is found to differ
significantly from the region of the GRS's potential vorticity anomaly. The
westward-going jet stream to the north of the GRS and the eastward-going jet
stream to its south are each found to have a large potential vorticity
``jump''. The jumps have opposite sign and as a consequence of their
interaction with the GRS, the shear imposed on the GRS is reduced. The
east-west to north-south aspect ratio of the GRS's potential vorticity anomaly
depends on the ratio of the imposed shear to the strength of the anomaly. The
aspect ratio is found to be $\approx$2:1, but without the opposing jumps it
would be much greater. The GRS's high-speed collar and quiescent interior
require that the potential vorticity in the interior be approximately half that
in the collar. No other persistent geophysical vortex has a significant minimum
of potential vorticity in its interior and laboratory vortices with such a
minimum are unstable.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 00:02:01 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Sep 2007 02:42:12 GMT"
}
] | 2008-01-10T00:00:00 | [
[
"Shetty",
"Sushil",
""
],
[
"Asay-Davis",
"Xylar S.",
""
],
[
"Marcus",
"Philip S.",
""
]
] |
0707.4194 | Micaela Oertel | V. Bernard, M. Oertel, E. Passemar, J. Stern | Tests of non-standard electroweak couplings of right-handed quarks | 56 pages, 14 figures, v2: references added, minor modifications in
the text, accepted for publication in JHEP | JHEP 0801:015,2008 | 10.1088/1126-6708/2008/01/015 | null | hep-ph hep-ex | null | The standard model can be interpreted as the leading order of a Low-Energy
Effective Theory (LEET) invariant under a higher non linearly realized symmetry
$S_{nat}\supset SU(2)_W \times U(1)_Y$ equipped with a systematic power
counting. Within the minimal version of this ``not quite decoupling'' LEET, the
dominant non-standard effect appears at next-to-leading order (NLO) and is a
modification of the couplings of fermions to W and Z. In particular, the
coupling of right-handed quarks to Z is modified and a direct coupling of
right-handed quarks to W emerges. Charged right-handed lepton currents are
forbidden by an additional discrete symmetry in the lepton sector originally
designed to suppress Dirac neutrino masses. A complete NLO analysis of
experimental constraints on these modified couplings is presented. Concerning
couplings of light quarks, the interface of the electroweak tests with QCD
aspects is discussed in detail.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:05:28 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Dec 2007 10:16:48 GMT"
}
] | 2009-01-06T00:00:00 | [
[
"Bernard",
"V.",
""
],
[
"Oertel",
"M.",
""
],
[
"Passemar",
"E.",
""
],
[
"Stern",
"J.",
""
]
] |
0707.4195 | Tad Hogg | Kay-Yut Chen and Tad Hogg | Experiments with Probabilistic Quantum Auctions | extended description of experiment setup and results | Quantum Information Processing 7:139-152 (2008) | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe human-subject laboratory experiments on probabilistic auctions
based on previously proposed auction protocols involving the simulated
manipulation and communication of quantum states. These auctions are
probabilistic in determining which bidder wins, or having no winner, rather
than always having the highest bidder win. Comparing two quantum protocols in
the context of first-price sealed bid auctions, we find the one predicted to be
superior by game theory also performs better experimentally. We also compare
with a conventional first price auction, which gives higher performance. Thus
to provide benefits, the quantum protocol requires more complex economic
scenarios such as maintaining privacy of bids over a series of related auctions
or involving allocative externalities.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 22:41:25 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Aug 2008 17:12:51 GMT"
}
] | 2009-03-31T00:00:00 | [
[
"Chen",
"Kay-Yut",
""
],
[
"Hogg",
"Tad",
""
]
] |
0707.4196 | Andrzej Madrecki Phd | Andrzej Madrecki | A short Brownian motion proof of the Riemann hypothesis | 26 pages | null | null | null | math.GM | null | We give a short probabilistic (a Brownian motion) proof of the Riemann
hypothesis based on some surprising, unexpected and deep algebraic conjecture
(MAC in short) concerning the relation between the Riemann zeta $\xi$ and a
trivial zeta $\zeta_{t}$. That algebraic conjecture was firstly discovered and
formulated in [MA]
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 23:20:10 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Madrecki",
"Andrzej",
""
]
] |
0707.4197 | Sean Sather-Wagstaff | Anders J. Frankild, Sean Sather-Wagstaff and Roger Wiegand | Ascent of module structures, vanishing of Ext, and extended modules | 16 pages, AMS-TeX; final version to appear in Michigan Math. J.;
corrected proof of Main Theorem and made minor editorial changes; v3 has
dedication to Mel Hochster | null | null | null | math.AC | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let $(R,\m)$ and $(S,\n)$ be commutative Noetherian local rings, and let
$\phi:R\to S$ be a flat local homomorphism such that $\m S = \n$ and the
induced map on residue fields $R/\m \to S/\n$ is an isomorphism. Given a
finitely generated $R$-module $M$, we show that $M$ has an $S$-module structure
compatible with the given $R$-module structure if and only if $\Ext^i_R(S,M)=0$
for each $i\ge 1$.
We say that an $S$-module $N$ is {\it extended} if there is a finitely
generated $R$-module $M$ such that $N\cong S\otimes_RM$. Given a short exact
sequence $0 \to N_1\to N \to N_2\to 0$ of finitely generated $S$-modules, with
two of the three modules $N_1,N,N_2$ extended, we obtain conditions forcing the
third module to be extended. We show that every finitely generated module over
the Henselization of $R$ is a direct summand of an extended module, but that
the analogous result fails for the $\m$-adic completion.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 23:25:30 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 16:18:27 GMT"
},
{
"version": "v3",
"created": "Tue, 19 Aug 2008 15:13:55 GMT"
}
] | 2008-08-19T00:00:00 | [
[
"Frankild",
"Anders J.",
""
],
[
"Sather-Wagstaff",
"Sean",
""
],
[
"Wiegand",
"Roger",
""
]
] |
0707.4198 | Russ Abbott | Russ Abbott | Reductionism, emergence, and levels of abstractions | This piece is to be submitted to CACM as a Viewpoint article. It is
only 1200 word because that's the word limit on such pieces. Updates (if any)
will be available at
http://cs.calstatela.edu/wiki/images/e/e2/Reductionism%2C_emergence%2C_and_levels_of_abstractions.doc | null | null | null | cs.OH | null | Can there be independent higher level laws of nature if everything is
reducible to the fundamental laws of physics? The computer science notion of
level of abstraction explains why there can -- illustrating how computational
thinking can solve one of philosophy's most vexing problems.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 23:52:32 GMT"
}
] | 2008-05-24T00:00:00 | [
[
"Abbott",
"Russ",
""
]
] |
0707.4199 | Svetlana Eliseeva | V. S. Beskin, S. A. Eliseeva | On the Possibility of the Detection of Extinct Radio Pulsars | 5 pages, 1 figure corrected version of the paper that was published
in Astronomy Letters | Astron.Lett.29:20-25,2003 | 10.1134/1.1537373 | null | astro-ph | null | We explore the possibilities for detecting pulsars that have ceased to
radiate in the radio band. We consider two models: the model with hindered
particle escape from the pulsar surface (first suggested by Ruderman and
Sutherland 1975) and the model with free particle escape (Arons 1981; Mestel
1999). In the model with hindered particle escape, the number of particles that
leave the pulsar magnetosphere is small and their radiation cannot be detected
with currently available instruments. At the same time, for the free particle
escape model, both the number of particles and the radiation intensity are high
enough for such pulsars to be detectable with the presently available receivers
such as GLAST and AGILE spacecrafts. It is also possible that extinct radio
pulsars can be among the unidentified EGRET sources.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 23:56:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Beskin",
"V. S.",
""
],
[
"Eliseeva",
"S. A.",
""
]
] |
0707.4200 | Pedro Castelo Ferreira Dr. | P. Castelo Ferreira and J. Dias de Deus | QCD Corrections to QED Vacuum Polarization | 15 pages, 4 figures; Final version | Eur.Phys.J.C54:539-545,2008 | 10.1140/epjc/s10052-008-0556-z | null | hep-ph | null | We compute QCD corrections to QED calculations for vacuum polarization in
background magnetic fields. Formally, the diagram for virtual $e\bar{e}$ loops
is identical to the one for virtual $q\bar{q}$ loops. However due to
confinement, or to the growth of $\alpha_s$ as $p^2$ decreases, a direct
calculation of the diagram is not allowed. At large $p^2$ we consider the
virtual $q\bar{q}$ diagram, in the intermediate region we discuss the role of
the contribution of quark condensates $\left< q\bar{q}\right>$ and at the
low-energy limit we consider the $\pi^0$, as well as charged pion $\pi^+\pi^-$
loops. Although these effects seem to be out of the measurement accuracy of
photon-photon laboratory experiments they may be relevant for $\gamma$-ray
burst propagation. In particular, for emissions from the center of the galaxy
(8.5 kpc), we show that the mixing between the neutral pseudo-scalar pion
$\pi_0$ and photons renders a deviation from the power-law spectrum in the
$TeV$ range. As for scalar quark condensates $\left< q\bar{q} right>$ and
virtual $q\bar{q}$ loops are relevant only for very high radiation density
$\sim 300 MeV/fm^3$ and very strong magnetic fields of order $\sim 10^{14} T$.
| [
{
"version": "v1",
"created": "Fri, 27 Jul 2007 23:57:01 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Apr 2008 10:25:19 GMT"
}
] | 2010-10-27T00:00:00 | [
[
"Ferreira",
"P. Castelo",
""
],
[
"de Deus",
"J. Dias",
""
]
] |
0707.4201 | Rapha\"el Ponge | Raphael Ponge (University of Toronto) | Noncommutative geometry and lower dimensional volumes in Riemannian
geometry | 12 pages | Lett. Math. Phys. 83 (2008) 19-32 | 10.1007/s11005-007-0199-2 | null | math.DG math.OA | null | In this paper we explain how to define "lower dimensional'' volumes of any
compact Riemannian manifold as the integrals of local Riemannian invariants.
For instance we give sense to the area and the length of such a manifold in any
dimension. Our reasoning is motivated by an idea of Connes and involves in an
essential way noncommutative geometry and the analysis of Dirac operators on
spin manifolds. However, the ultimate definitions of the lower dimensional
volumes don't involve noncommutative geometry or spin structures at all.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 01:16:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ponge",
"Raphael",
"",
"University of Toronto"
]
] |
0707.4202 | Pablo A. Ferrari | Pablo A. Ferrari, James B. Martin | Multiclass Hammersley-Aldous-Diaconis process and multiclass-customer
queues | 21 pages, 6 figures | null | null | null | math.PR math-ph math.MP | null | In the Hammersley-Aldous-Diaconis process infinitely many particles sit in R
and at most one particle is allowed at each position. A particle at x$ whose
nearest neighbor to the right is at y, jumps at rate y-x to a position
uniformly distributed in the interval (x,y). The basic coupling between
trajectories with different initial configuration induces a process with
different classes of particles. We show that the invariant measures for the
two-class process can be obtained as follows. First, a stationary M/M/1 queue
is constructed as a function of two homogeneous Poisson processes, the arrivals
with rate \lambda and the (attempted) services with rate \rho>\lambda. Then put
the first class particles at the instants of departures (effective services)
and second class particles at the instants of unused services. The procedure is
generalized for the n-class case by using n-1 queues in tandem with n-1
priority-types of customers. A multi-line process is introduced; it consists of
a coupling (different from Liggett's basic coupling), having as invariant
measure the product of Poisson processes. The definition of the multi-line
process involves the dual points of the space-time Poisson process used in the
graphical construction of the system. The coupled process is a transformation
of the multi-line process and its invariant measure the transformation
described above of the product measure.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 01:19:23 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Ferrari",
"Pablo A.",
""
],
[
"Martin",
"James B.",
""
]
] |
0707.4203 | Deanna Needell | Deanna Needell, Roman Vershynin | Uniform Uncertainty Principle and signal recovery via Regularized
Orthogonal Matching Pursuit | This is the final version of the paper, including referee suggestions | null | null | null | math.NA | null | This paper seeks to bridge the two major algorithmic approaches to sparse
signal recovery from an incomplete set of linear measurements --
L_1-minimization methods and iterative methods (Matching Pursuits). We find a
simple regularized version of the Orthogonal Matching Pursuit (ROMP) which has
advantages of both approaches: the speed and transparency of OMP and the strong
uniform guarantees of the L_1-minimization. Our algorithm ROMP reconstructs a
sparse signal in a number of iterations linear in the sparsity (in practice
even logarithmic), and the reconstruction is exact provided the linear
measurements satisfy the Uniform Uncertainty Principle.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 02:38:43 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Aug 2007 22:34:48 GMT"
},
{
"version": "v3",
"created": "Sun, 26 Aug 2007 04:07:23 GMT"
},
{
"version": "v4",
"created": "Sat, 15 Mar 2008 18:15:13 GMT"
}
] | 2008-03-15T00:00:00 | [
[
"Needell",
"Deanna",
""
],
[
"Vershynin",
"Roman",
""
]
] |
0707.4204 | Cesare Tronci | Darryl D. Holm, Vakhtang Putkaradze, Cesare Tronci | Double bracket dissipation in kinetic theory for particles with
anisotropic interactions | 19 pages; no figures. Submitted to Proc. Roy. Soc. A | null | 10.1098/rspa.2010.0043 | null | nlin.AO cond-mat.mes-hall nlin.PS physics.chem-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We derive equations of motion for the dynamics of anisotropic particles
directly from the dissipative Vlasov kinetic equations, with the dissipation
given by the double bracket approach (Double Bracket Vlasov, or DBV). The
moments of the DBV equation lead to a nonlocal form of Darcy's law for the mass
density. Next, kinetic equations for particles with anisotropic interaction are
considered and also cast into the DBV form. The moment dynamics for these
double bracket kinetic equations is expressed as Lie-Darcy continuum equations
for densities of mass and orientation. We also show how to obtain a
Smoluchowski model from a cold plasma-like moment closure of DBV. Thus, the
double bracket kinetic framework serves as a unifying method for deriving
different types of dynamics, from density--orientation to Smoluchowski
equations. Extensions for more general physical systems are also discussed.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 17:08:56 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Apr 2010 16:50:37 GMT"
}
] | 2010-04-26T00:00:00 | [
[
"Holm",
"Darryl D.",
""
],
[
"Putkaradze",
"Vakhtang",
""
],
[
"Tronci",
"Cesare",
""
]
] |
0707.4205 | Paulo Tabuada | Giordano Pola and Paulo Tabuada | Symbolic Models for Nonlinear Control Systems: Alternating Approximate
Bisimulations | null | null | null | null | math.OC | null | Symbolic models are abstract descriptions of continuous systems in which
symbols represent aggregates of continuous states. In the last few years there
has been a growing interest in the use of symbolic models as a tool for
mitigating complexity in control design. In fact, symbolic models enable the
use of well known algorithms in the context of supervisory control and
algorithmic game theory, for controller synthesis. Since the 1990's many
researchers faced the problem of identifying classes of dynamical and control
systems that admit symbolic models. In this paper we make a further progress
along this research line by focusing on control systems affected by
disturbances. Our main contribution is to show that incrementally globally
asymptotically stable nonlinear control systems with disturbances admit
symbolic models. When specializing these results to linear systems, we show
that these symbolic models can be easily constructed.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 03:34:58 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Pola",
"Giordano",
""
],
[
"Tabuada",
"Paulo",
""
]
] |
0707.4206 | Kirill Shtengel | Parsa Bonderson, Kirill Shtengel and J. K. Slingerland | Interferometry of non-Abelian Anyons | 4+epsilon pages (where epsilon=58), 3 figures; v2: minor corrections
and clarifications made, references added | Annals Phys. 323, 2709-2755 (2008) | 10.1016/j.aop.2008.01.012 | null | quant-ph cond-mat.mes-hall hep-th | null | We develop the general quantum measurement theory of non-Abelian anyons
through interference experiments. The paper starts with a terse introduction to
the theory of anyon models, focusing on the basic formalism necessary to apply
standard quantum measurement theory to such systems. This is then applied to
give a detailed analysis of anyonic charge measurements using a Mach-Zehnder
interferometer for arbitrary anyon models. We find that, as anyonic probes are
sent through the legs of the interferometer, superpositions of the total
anyonic charge located in the target region collapse when they are
distinguishable via monodromy with the probe anyons, which also determines the
rate of collapse. We give estimates on the number of probes needed to obtain a
desired confidence level for the measurement outcome distinguishing between
charges, and explicitly work out a number of examples for some significant
anyon models. We apply the same techniques to describe interferometry
measurements in a double point-contact interferometer realized in fractional
quantum Hall systems. To lowest order in tunneling, these results essentially
match those from the Mach-Zehnder interferometer, but we also provide the
corrections due to processes involving multiple tunnelings. Finally, we give
explicit predictions describing state measurements for experiments in the
Abelian hierarchy states, the non-Abelian Moore-Read state at $\nu=5/2$ and
Read-Rezayi state at $\nu = 12/5$.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:14:23 GMT"
},
{
"version": "v2",
"created": "Sun, 13 Jan 2008 08:36:23 GMT"
}
] | 2009-09-21T00:00:00 | [
[
"Bonderson",
"Parsa",
""
],
[
"Shtengel",
"Kirill",
""
],
[
"Slingerland",
"J. K.",
""
]
] |
0707.4207 | Tomohiro Sasamoto | Alexei Borodin, Patrik L. Ferrari, Tomohiro Sasamoto | Large time asymptotics of growth models on space-like paths II: PNG and
parallel TASEP | 39 pages,6 figures | Comm. Math. Phys. 283 (2008) 417-449 | 10.1007/s00220-008-0515-4 | null | math-ph cond-mat.stat-mech math.MP math.PR | null | We consider the polynuclear growth (PNG) model in 1+1 dimension with flat
initial condition and no extra constraints. The joint distributions of surface
height at finitely many points at a fixed time moment are given as marginals of
a signed determinantal point process. The long time scaling limit of the
surface height is shown to coincide with the Airy_1 process. This result holds
more generally for the observation points located along any space-like path in
the space-time plane. We also obtain the corresponding results for the discrete
time TASEP (totally asymmetric simple exclusion process) with parallel update.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:13:05 GMT"
}
] | 2010-03-09T00:00:00 | [
[
"Borodin",
"Alexei",
""
],
[
"Ferrari",
"Patrik L.",
""
],
[
"Sasamoto",
"Tomohiro",
""
]
] |
0707.4208 | Balasubramanian Ananthanarayan | B. Ananthanarayan, Keshav Choudhary, Lishibanya Mohapatra, Indrajeet
Patil, Avinash Rustagi, K. Shivaraj | Research News -- Observation of Exotic Heavy Baryons | 4 pages, 1 figure | Curr.Sci.93:451-452,2007 | null | null | physics.pop-ph hep-ex hep-ph | null | We review the recent discoveries of exotic heavy baryons at the Fermi
National Accelerator Laboratory.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:21:10 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Ananthanarayan",
"B.",
""
],
[
"Choudhary",
"Keshav",
""
],
[
"Mohapatra",
"Lishibanya",
""
],
[
"Patil",
"Indrajeet",
""
],
[
"Rustagi",
"Avinash",
""
],
[
"Shivaraj",
"K.",
""
]
] |
0707.4209 | Balasubramanian Ananthanarayan | B. Ananthanarayan, Keshav Choudhary, Lishibanya Mohapatra, Indrajeet
Patil, Avinash Rustagi, K. Shivaraj | Research News -- Observation of oscillation phenomena in heavy meson
systems | 6 pages, 2 figures | Curr.Sci.93:602-604,2007 | null | null | physics.pop-ph hep-ex hep-ph | null | We review the recent discoveries of rare oscillation phenomena in certain
heavy neutral meson systems.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:27:01 GMT"
}
] | 2007-09-09T00:00:00 | [
[
"Ananthanarayan",
"B.",
""
],
[
"Choudhary",
"Keshav",
""
],
[
"Mohapatra",
"Lishibanya",
""
],
[
"Patil",
"Indrajeet",
""
],
[
"Rustagi",
"Avinash",
""
],
[
"Shivaraj",
"K.",
""
]
] |
0707.4210 | Jim Hoste | Adam Boocher (University of Notre Dame), Jay Daigle (Pomona College),
Jim Hoste (Pitzer College), Wenjing Zheng (University of California,
Berkeley) | Sampling Lissajous and Fourier knots | 34 pages, 5 figures, 18 tables | null | null | null | math.GT | null | A Lissajous knot is one that can be parameterized by a single cosine function
in each coordinate. Lissajous knots are highly symmetric, and for this reason,
not all knots are Lissajous. We prove several theorems which allow us to place
bounds on the number of Lissajous knot types with given frequencies and to
efficiently sample all possible Lissajous knots with a given set of
frequencies. In particular, we systematically tabulate all Lissajous knots with
small frequencies and as a result substantially enlarge the tables of known
Lissajous knots.
A Fourier (i, j, k) knot is similar to a Lissajous knot except that each
coordinate is now described by a finite sum of i, j, and k cosine functions
respectively. According to Lamm, every knot is a Fourier-(1,1,k) knot for some
k. By randomly searching the set of Fourier-(1,1,2) knots we find that all
2-bridge knots up to 14 crossings are either Lissajous or Fourier-(1,1,2)
knots. We show that all twist knots are Fourier-(1,1,2) knots and give evidence
suggesting that all torus knots are Fourier-(1,1,2) knots.
As a result of our computer search, several knots with relatively small
crossing numbers are identified as potential counterexamples to interesting
conjectures.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:51:55 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Boocher",
"Adam",
"",
"University of Notre Dame"
],
[
"Daigle",
"Jay",
"",
"Pomona College"
],
[
"Hoste",
"Jim",
"",
"Pitzer College"
],
[
"Zheng",
"Wenjing",
"",
"University of California,\n Berkeley"
]
] |
0707.4211 | Cheongho Han | Cheongho Han (Chungbuk Natl. Univ., Korea) | Expansion of the Planet Detection Channels in Next-Generation
Microlensing Surveys | 6 pages, 3 figures, one table | null | 10.1086/522024 | null | astro-ph | null | We classify various types of planetary lensing signals and the channels of
detecting them. We estimate the relative frequencies of planet detections
through the individual channels with special emphasis on the new channels to be
additionally provided by future lensing experiments that will survey wide
fields continuously at high cadence by using very large-format imaging cameras.
From this investigation, we find that the fraction of wide-separation planets
that would be discovered through the new channels of detecting planetary
signals as independent and repeating events would be substantial. We estimate
that the fraction of planets detectable through the new channels would comprise
~15 -- 30% of all planets depending on the models of the planetary separation
distribution and mass ratios of planets. Considering that a significant
fraction of planets might exist in the form of free-floating planets, the
frequency of planets to be detected through the new channel would be even
higher. With the expansion of the channels of detecting planet, future lensing
surveys will greatly expand the range of planets to be probed.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 04:58:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Han",
"Cheongho",
"",
"Chungbuk Natl. Univ., Korea"
]
] |
0707.4212 | Zhangjin Chen | Zhangjin Chen, Toru Morishita, Anh-Thu Le, C. D. Lin | Analysis of two-dimensional high-energy photoelectron momentum
distributions in single ionization of atoms by intense laser pulses | 12 pages, 10 figures | null | 10.1103/PhysRevA.76.043402 | null | physics.atom-ph | null | We analyzed the two-dimensional (2D) electron momentum distributions of
high-energy photoelectrons of atoms in an intense laser field using the
second-order strong field approximation (SFA2). The SFA2 accounts for the
rescattering of the returning electron with the target ion to first order and
its validity is established by comparing with results obtained by solving the
time-dependent Schr\"{o}dinger equation (TDSE) for short pulses. By analyzing
the SFA2 theory, we confirmed that the yield along the back rescattered ridge
(BRR) in the 2D momentum spectra can be interpreted as due to the elastic
scattering in the backward directions by the returning electron wave packet.
The characteristics of the extracted electron wave packets for different laser
parameters are analyzed, including their dependence on the laser intensity and
pulse duration. For long pulses we also studied the wave packets from the first
and the later returns.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 05:18:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chen",
"Zhangjin",
""
],
[
"Morishita",
"Toru",
""
],
[
"Le",
"Anh-Thu",
""
],
[
"Lin",
"C. D.",
""
]
] |
0707.4213 | Tian Yang | Tian Yang | A Batalin-Vilkovisky Algebra structure on the Hochschild Cohomology of
Truncated Polynomials | null | null | null | null | math.AT math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The main result of this paper is to calculate the Batalin-Vilkovisky
structure of $HH^*(C^*(\mathbf{K}P^n;R);C^*(\mathbf{K}P^n;R))$ for $
\mathbf{K}=\mathbb{C}$ and $\mathbb{H}$, and $R=\mathbb{Z}$ and any field; and
shows that in the special case when $M=\mathbb{C}P^1=S^2$, and $R=\mathbb{Z}$,
this structure can not be identified with the BV-structure of
$\mathbb{H}_*(LS^2;\mathbb{Z})$ computed by Luc Memichi in \cite{menichi2}.
However, the induced Gerstenhaber structures are still identified in this case.
Moreover, according to a recent work of Y.Felix and J.Thomas
\cite{felix--thomas}, the main result of the present paper eventually
calculates the BV-structure of the rational loop homology,
$\mathbb{H}_*(L\mathbb{C}P^n;\mathbb{Q})$ and
$\mathbb{H}_*(L\mathbb{H}P^n;\mathbb{Q})$, of projective spaces.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 06:01:53 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 19:27:58 GMT"
},
{
"version": "v3",
"created": "Fri, 3 Aug 2007 04:44:50 GMT"
},
{
"version": "v4",
"created": "Wed, 14 Apr 2010 07:18:31 GMT"
},
{
"version": "v5",
"created": "Thu, 22 Apr 2010 05:04:33 GMT"
}
] | 2010-04-23T00:00:00 | [
[
"Yang",
"Tian",
""
]
] |
0707.4214 | Ying Hu | Marco Fuhrman (Dipartimento Di Matematica), Ying Hu (IRMAR), Gianmario
Tessitore (Dipartimento Di Matematica E Applicazioni) | Ergodic BSDEs and Optimal Ergodic Control in Banach Spaces | null | null | null | null | math.PR | null | In this paper we introduce a new kind of Backward Stochastic Differential
Equations, called ergodic BSDEs, which arise naturally in the study of optimal
ergodic control. We study the existence, uniqueness and regularity of solution
to ergodic BSDEs. Then we apply these results to the optimal ergodic control of
a Banach valued stochastic state equation. We also establish the link between
the ergodic BSDEs and the associated Hamilton-Jacobi-Bellman equation.
Applications are given to ergodic control of stochastic partial differential
equations.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 05:54:32 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Fuhrman",
"Marco",
"",
"Dipartimento Di Matematica"
],
[
"Hu",
"Ying",
"",
"IRMAR"
],
[
"Tessitore",
"Gianmario",
"",
"Dipartimento Di Matematica E Applicazioni"
]
] |
0707.4215 | Inessa Epstein | Inessa Epstein | Orbit inequivalent actions of non-amenable groups | Wrote introduction, references, etc | null | null | null | math.GR | null | Consider two free measure preserving group actions $\Gamma \actson (X, \mu),
\Delta \actson (X, \mu)$, and a measure preserving action $\Delta \actson^a (Z,
\nu)$ where $(X, \mu), (Z, \nu)$ are standard probability spaces. We show how
to construct free measure preserving actions $\Gamma \actson^c (Y, m)$, $\Delta
\actson^d (Y, m)$ on a standard probability space such that $E_{\Delta}^d
\subset E_{\Gamma}^c$ and $d$ has $a$ as a factor. This generalizes the
standard notion of co-induction of actions of groups from actions of subgroups.
We then use this construction to show that if $\Gamma$ is a countable
non-amenable group, then $\Gamma$ admits continuum many orbit inequivalent
free, measure preserving, ergodic actions on a standard probability space.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 06:25:31 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Mar 2008 00:21:50 GMT"
}
] | 2008-03-12T00:00:00 | [
[
"Epstein",
"Inessa",
""
]
] |
0707.4216 | Gennady Chuev N. | Gennady N. Chuev, Pascal Quemerais, and Jason Crain | Nature of the metal-nonmetal transition in metal-ammonia solutions. I.
Solvated electrons at low metal concentrations | 13 figures, 42 pages | null | 10.1063/1.2812244 | null | cond-mat.stat-mech cond-mat.str-el | null | Using a theory of polarizable fluids, we extend a variational treatment of an
excess electron to the many-electron case corresponding to finite metal
concentrations in metal-ammonia solutions (MAS). We evaluate dielectric,
optical, and thermodynamical properties of MAS at low metal concentrations. Our
semi-analytical calculations based on a mean-spherical approximation correlate
well with the experimental data on the concentration and the temperature
dependencies of the dielectric constant and the optical absorption spectrum.
The properties are found to be mainly determined by the induced dipolar
interactions between localized solvated electrons, which result in the two main
effects: the dispersion attractions between the electrons and a sharp increase
in the static dielectric constant of the solution. The first effect provides a
classical phase separation for the light alkali metal solutes (Li, Na, K) below
a critical temperature. The second effect leads to a dielectric instability,
i.e., polarization catastrophe, which is the onset of metallization. The locus
of the calculated critical concentrations is in a good agreement with the
experimental phase diagram of Na-NH3 solutions. The proposed mechanism of the
metal-nonmetal transition is quite general and may occur in systems involving
self-trapped quantum quasiparticles.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 10:16:08 GMT"
},
{
"version": "v2",
"created": "Sat, 4 Aug 2007 18:06:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chuev",
"Gennady N.",
""
],
[
"Quemerais",
"Pascal",
""
],
[
"Crain",
"Jason",
""
]
] |
0707.4217 | Bei Jia | Bei Jia, Xi-Guo Lee and Peng-Ming Zhang | Energy-momentum of a Cosmological Brane Model and the Gauge Hierarchy | 11 pages; accepted by International Journal of Theoretical Physics | Int.J.Theor.Phys.47:3391-3400,2008 | 10.1007/s10773-008-9770-6 | null | hep-th gr-qc | null | We analyze the general covariant energy-momentum tensor of the gravitational
system in genreal five-dimensional cosmological brane-world models. Then
through calculating this energy-momentum for the cosmological generalization of
the Randall-Sundrum model, which includes the original RS model as the static
limit, we are able to show that the weakness of the gravitation on the
"visible" brane is a general feature of this model. This is the origin of the
gauge hierarchy from a gravitational point of view. Our results are also
consistent with the fact that a gravitational system has vanishing total
energy.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 07:05:12 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jun 2008 11:52:22 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Jia",
"Bei",
""
],
[
"Lee",
"Xi-Guo",
""
],
[
"Zhang",
"Peng-Ming",
""
]
] |
0707.4218 | Sergei V. Ketov | Tomoya Hatanaka and Sergei V. Ketov | N=1/2 supergravity with matter in four Euclidean dimensions | 21 pages, LaTeX, no figures; a reference added | Nucl.Phys.B794:495-511,2008 | 10.1016/j.nuclphysb.2007.10.020 | null | hep-th | null | An N=1/2 supergravity in four Euclidean spacetime dimensions, coupled to both
vector- and scalar-multiplet matter, is constructed for the first time. We
begin with the standard (1,1) conformally extended supergravity in four
Euclidean dimensions, and freeze out the graviphoton field strength to an
arbitrary (fixed) self-dual field (the so-called C-deformation). Though a
consistency of such procedure with local supersymmetry is not guaranteed, we
find a simple consistent set of algebraic constraints that reduce the local
supersymmetry by 3/4 and eliminate the corresponding gravitini. The final field
theory (after the superconformal gauge-fixing) has the residual local N=(0,1/2)
or just N=1/2 supersymmetry with only one chiral gravitino as the corresponding
gauge field. Our theory is not `Lorentz'-invariant because of the non-vanishing
self-dual graviphoton vacuum expectation value, which is common to the
C-deformed N=1/2 rigidly supersymmetric field theories constructed in a
non-anticommutative superspace.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 07:07:48 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Oct 2007 06:45:50 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hatanaka",
"Tomoya",
""
],
[
"Ketov",
"Sergei V.",
""
]
] |
0707.4219 | Weiping Zhang | Huitao Feng, Guangbo Xu and Weiping Zhang | Real embeddings, eta invariant and Chern-Simons current | 20 pages | Pure and Applied Mathematics Quarterly 5 (2009), 1113-1137 | null | null | math.DG math.KT | null | We present an alternate proof of the Bismut-Zhang localization formula for
$\eta$-invariants without using the analytic techniques developed by
Bismut-Lebeau. A Riemann-Roch property for Chern-Simons currents, which is of
independent interest, is established in due course.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 08:12:46 GMT"
}
] | 2012-05-15T00:00:00 | [
[
"Feng",
"Huitao",
""
],
[
"Xu",
"Guangbo",
""
],
[
"Zhang",
"Weiping",
""
]
] |
0707.4220 | Gennady Valyavin G | Kang-Min Kim, Inwoo Han, Gennady G. Valyavin, Sergei Plachinda, Jeong
Gyun Jang, Be-Ho Jang, Hyeon Cheol Seong, Byeong-Cheol Lee, Dong-Il Kang,
Byeong-Gon Park, Tae Seog Yoon, Steven S. Vogt | The BOES spectropolarimeter for Zeeman measurements of stellar magnetic
fields | 12 figures | null | 10.1086/521959 | null | astro-ph | null | We introduce a new polarimeter installed on the high-resolution fiber-fed
echelle spectrograph (called BOES) of the 1.8-m telescope at the Bohyunsan
Optical Astronomy Observatory, Korea. The instrument is intended to measure
stellar magnetic fields with high-resolution (R $\sim$ 60000)
spectropolarimetric observations of intrinsic polarization in spectral lines.
In this paper we describe the spectropolarimeter and present test observations
of the longitudinal magnetic fields in some well-studied F-B main sequence
magnetic stars (m_v < 8.8^m). The results demonstrate that the instrument has a
high precision ability of detecting the fields of these stars with typical
accuracies ranged from about 2G to a few tens of gauss.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 08:34:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kim",
"Kang-Min",
""
],
[
"Han",
"Inwoo",
""
],
[
"Valyavin",
"Gennady G.",
""
],
[
"Plachinda",
"Sergei",
""
],
[
"Jang",
"Jeong Gyun",
""
],
[
"Jang",
"Be-Ho",
""
],
[
"Seong",
"Hyeon Cheol",
""
],
[
"Lee",
"Byeong-Cheol",
""
],
[
"Kang",
"Dong-Il",
""
],
[
"Park",
"Byeong-Gon",
""
],
[
"Yoon",
"Tae Seog",
""
],
[
"Vogt",
"Steven S.",
""
]
] |
0707.4221 | Enrique Alvarez | Enrique Alvarez and Anton F. Faedo | A comment on the matter-graviton coupling | 17 pages, 4 figures. References added | Phys.Rev.D76:124016,2007 | 10.1103/PhysRevD.76.124016 | IFT-UAM/CSIC-07-32 | hep-th | null | We point out a generic inconsistency of the coupling of ordinary gravity as
described by general relativity with matter invariant under the subgroup of
unimodular diffeomorphisms (TDiffs), and some previously studied exceptions are
pointed out. The most general Lagrangian invariant under TDiff up to dimension
five operators is determined, and restrictions on parameters coming from
existing observations are studied in some cases.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 08:40:15 GMT"
},
{
"version": "v2",
"created": "Sun, 23 Sep 2007 15:32:19 GMT"
},
{
"version": "v3",
"created": "Mon, 24 Sep 2007 20:51:46 GMT"
},
{
"version": "v4",
"created": "Wed, 26 Sep 2007 20:35:39 GMT"
},
{
"version": "v5",
"created": "Tue, 30 Oct 2007 22:29:34 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Alvarez",
"Enrique",
""
],
[
"Faedo",
"Anton F.",
""
]
] |
0707.4222 | I. A. Fomin | I.A. Fomin | Long-range order in the A-like phase of superfluid 3He in aerogel | A contribution to QFS 2007 in Kazan, revised for publication in the
Proceedings | null | 10.1007/s10909-007-9572-x | null | cond-mat.dis-nn | null | A mutual action of the random anisotropy brought in the superfluid 3He by
aerogel and of the global anisotropy caused by its deformation is considered.
Strong global anisotropy tends to suppress fluctuations of orientation of the
order parameter and stabilizes ABM order parameter. In a limit of vanishing
anisotropy these fluctuations are getting critical. It is argued that still in
a region of small fluctuations the average order parameter can acquire "robust"
component. This component maintains a long-range order even in a limit of
vanishing global anisotropy.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 08:46:25 GMT"
},
{
"version": "v2",
"created": "Sun, 30 Sep 2007 17:03:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fomin",
"I. A.",
""
]
] |
0707.4223 | Li-Xiang Cen | Li-Xiang Cen, Z. D. Wang | Spatial reflection and renormalization group flow of quantum many-body
systems with matrix product state representation | updated version, accepted by Europhys. Lett. | EPL, 82 (2008) 40003 | 10.1209/0295-5075/82/40003 | null | quant-ph cond-mat.stat-mech | null | The property of quantum many-body systems under spatial reflection and the
relevant physics of renormalization group (RG) procedure are revealed. By
virtue of the matrix product state (MPS) representation, various attributes for
translational invariant systems associated with spatial reflection are
manifested. We demonstrate subsequently a conservation rule of the conjugative
relation for reflectional MPS pairs under RG transformations and illustrate
further the property of the fixed points of RG flows. Finally, we show that a
similar rule exists with respect to the target states in the density matrix
renormalization group algorithm.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 08:50:11 GMT"
},
{
"version": "v2",
"created": "Mon, 31 Mar 2008 13:59:13 GMT"
}
] | 2011-08-08T00:00:00 | [
[
"Cen",
"Li-Xiang",
""
],
[
"Wang",
"Z. D.",
""
]
] |
0707.4224 | Davron Matrasulov | K. R. Nasriddinov, N. Z. Rajabov, N. E. Iskandarov | The $\phi$ - Meson Physics in the Chirial Model | null | null | null | null | hep-ph | null | The $\phi \to K^+K^-,K^{0}_{L},K^{0}_{S},K^{0}\bar K^0$ decays are studied
using the method of phenomenological chiral Lagrangians. Calculated values for
partial widths for these decay channels are compared with available
experimental data.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 09:23:10 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Aug 2007 06:47:04 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Nasriddinov",
"K. R.",
""
],
[
"Rajabov",
"N. Z.",
""
],
[
"Iskandarov",
"N. E.",
""
]
] |
0707.4225 | Eduard P. Kontar | Eduard P. Kontar, A. Gordon Emslie, Anna Maria Massone, Michele Piana,
John C. Brown, and Marco Prato | Electron-Electron Bremsstrahlung Emission and the Inference of Electron
Flux Spectra in Solar Flares | 7 pages, 5 figures, submitted to Astrophysical Journal | null | 10.1086/521977 | null | astro-ph | null | Although both electron-ion and electron-electron bremsstrahlung contribute to
the hard X-ray emission from solar flares, the latter is normally ignored. Such
an omission is not justified at electron (and photon) energies above $\sim 300$
keV, and inclusion of the additional electron-electron bremsstrahlung in
general makes the electron spectrum required to produce a given hard X-ray
spectrum steeper at high energies.
Unlike electron-ion bremsstrahlung, electron-electron bremsstrahlung cannot
produce photons of all energies up to the maximum electron energy involved. The
maximum possible photon energy depends on the angle between the direction of
the emitting electron and the emitted photon, and this suggests a diagnostic
for an upper cutoff energy and/or for the degree of beaming of the accelerated
electrons.
We analyze the large event of January 17, 2005 observed by RHESSI and show
that the upward break around 400 keV in the observed hard X-ray spectrum is
naturally accounted for by the inclusion of electron-electron bremsstrahlung.
Indeed, the mean source electron spectrum recovered through a regularized
inversion of the hard X-ray spectrum, using a cross-section that includes both
electron-ion and electron-electron terms, has a relatively constant spectral
index $\delta$ over the range from electron kinetic energy $E = 200$ keV to $E
= 1$ MeV. However, the level of detail discernible in the recovered electron
spectrum is not sufficient to determine whether or not any upper cutoff energy
exists.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 09:32:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kontar",
"Eduard P.",
""
],
[
"Emslie",
"A. Gordon",
""
],
[
"Massone",
"Anna Maria",
""
],
[
"Piana",
"Michele",
""
],
[
"Brown",
"John C.",
""
],
[
"Prato",
"Marco",
""
]
] |
0707.4226 | Chengming Bai | Chengming Bai | A Unified Algebraic Approach to Classical Yang-Baxter Equation | To appear in Journal of Physics A: Mathematical and Theoretical | Journal of Physics A: Mathematical and Theoretical 40 (2007)
11073-11082 | 10.1088/1751-8113/40/36/007 | null | math.QA math-ph math.MP | null | In this paper, the different operator forms of classical Yang-Baxter equation
are given in the tensor expression through a unified algebraic method. It is
closely related to left-symmetric algebras which play an important role in many
fields in mathematics and mathematical physics. By studying the relations
between left-symmetric algebras and classical Yang-Baxter equation, we can
construct left-symmetric algebras from certain classical r-matrices and
conversely, there is a natural classical r-matrix constructed from a
left-symmetric algebra which corresponds to a parak\"ahler structure in
geometry. Moreover, the former in a special case gives an algebraic
interpretation of the ``left-symmetry'' as a Lie bracket ``left-twisted'' by a
classical r-matrix.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 09:44:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bai",
"Chengming",
""
]
] |
0707.4227 | Vadim Loktev | V.M. Kalita, I.M. Ivanova and V.M. Loktev | Magnetization and Magnetoscrition of van Vleck antiferromagnets with
magnetic anisotropy of "easy-plane" type | 21 pages, 6 figures | null | 10.1103/PhysRevB.78.104415 | null | cond-mat.stat-mech | null | The theoretical description of quantum phase transition, induced by the
external magnetic field, into antiferromagnetic state in the van Vleck -
singlet - magnet with a single-ion anisotropy of "easy-plane" type and ion spin
S=1 is proposed. It is shown that the spin polarization of the ground
non-degenerated state proves to be the order parameter of such a transition and
that the Landau thermodynamic approach can be employed for its (transition)
description. The magnetic properties which include the field behavior of the
magnetization and magnetic susceptibility of the antiferromagnetic phase in the
fields of different directions are studied. The peculiarities of induced
magnetostriction in van Vleck antiferromagnet, which as well as magnetization
has a singularity in the phase transition point, are investigated. An attempt
is made for qualitative comparison of results obtained with avaliable
experimental data.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 10:06:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kalita",
"V. M.",
""
],
[
"Ivanova",
"I. M.",
""
],
[
"Loktev",
"V. M.",
""
]
] |
0707.4228 | Kyung Taec Kim | Kyung Taec Kim, Kyung Sik Kang, Mi Na Park, Tayyab Imran, G. Umesh,
and Chang Hee Nam | Comparison of RABITT and FROG measurements in the temporal
characterization of attosecond pulse trains | null | null | null | null | physics.optics physics.atom-ph | null | The attosecond high harmonic pulses obtained from a long Ar-filled gas cell
were characterized by two techniques - the reconstruction of attosecond beating
by interference of two-photon transition (RABITT) and frequency-resolved
optical gating (FROG) methods. The pulse durations obtained by RABITT and FROG
methods agreed within 10 %.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 11:02:00 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Kim",
"Kyung Taec",
""
],
[
"Kang",
"Kyung Sik",
""
],
[
"Park",
"Mi Na",
""
],
[
"Imran",
"Tayyab",
""
],
[
"Umesh",
"G.",
""
],
[
"Nam",
"Chang Hee",
""
]
] |
0707.4229 | Bhaskar Kaviraj Mr. | B. Kaviraj, F. Alves | Giant Magneto-impedance in stress-annealed Finemet/Copper/Finemet based
trilayer structures | 8 pages, 4 figures submitted to Solid State Communications | null | 10.1016/j.physb.2007.10.257 | null | cond-mat.mtrl-sci | null | The resistive and reactive components of magneto-impedance (MI) for
Finemet/Copper/Finemet sandwiched structures based on stress-annealed
nanocrystalline Fe75Si15B6Cu1Nb3 ribbons as functions of different fields
(longitudinal and perpendicular) and frequencies have been measured and
analyzed. Maximum magneto-resistance and magneto-inductance ratios of 700% and
450% have been obtained in 30-600 kHz frequency range respectively. These large
magneto-resistance and magneto-inductive ratios are a direct consequence of the
large effective relative permeability due to the closed magnetic flux path in
the trilayer structure. The influence of perpendicular bias fields (Hper) in
the Longitudinal Magneto-impedance (LMI) configuration greatly improves the MI
ratios and sensitivities. The maximum MI ratio for the resistive part increases
to as large as 2500% for Hper ~ 1 Oe. The sensitivity of the magneto-resistance
increases from 48%/Oe to 288%/Oe at 600 kHz frequency with the application of
Hper ~ 30 Oe. Such high increase in MI ratios and sensitivities with
perpendicular bias fields are due to the formation the favourable (transverse)
domain structures.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 10:11:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kaviraj",
"B.",
""
],
[
"Alves",
"F.",
""
]
] |
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