id
stringlengths 9
16
| submitter
stringlengths 1
64
⌀ | authors
stringlengths 3
36.7k
| title
stringlengths 1
382
| comments
stringlengths 1
1.15k
⌀ | journal-ref
stringlengths 1
557
⌀ | doi
stringlengths 7
153
⌀ | report-no
stringlengths 1
479
⌀ | categories
stringlengths 5
125
| license
stringclasses 9
values | abstract
stringlengths 6
6.09k
| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.0430 | Branislav Rovan | Peter Ga\v{z}i, Branislav Rovan | Assisted Problem Solving and Decompositions of Finite Automata | 14 pages | null | null | null | cs.CC | null | A study of assisted problem solving formalized via decompositions of
deterministic finite automata is initiated. The landscape of new types of
decompositions of finite automata this study uncovered is presented. Languages
with various degrees of decomposability between undecomposable and perfectly
decomposable are shown to exist.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 14:54:53 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Gaži",
"Peter",
""
],
[
"Rovan",
"Branislav",
""
]
] |
0707.0431 | Huguet Eric | A. Rabeie, E. Huguet, J. Renaud | Wick ordering for coherent state quantization in 1+1 de Sitter space | Accepted in Phys. Lett. A | Phys.Lett.A370:123-125,2007 | 10.1016/j.physleta.2007.05.053 | null | math-ph math.MP | null | We show that the coherent state quantization of massive particles in 1+1 de
Sitter space exhibits an ordering property: There exist some classical
observables $A$ and $A^*$ such that $O_{A^{*p}}O_{A^q}=O_{A^{*p} A^q}$ $p, q
\in \Z$, where $O_A$ is the quantum observable corresponding to the classical
observable $A$.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 14:56:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Rabeie",
"A.",
""
],
[
"Huguet",
"E.",
""
],
[
"Renaud",
"J.",
""
]
] |
0707.0432 | Sandra Spiroff | Paul Roberts, Sandra Spiroff | An algebraic proof of the commutativity of the intersection with
divisors | 14 pp; to appear in J. Algebra | null | null | null | math.AC math.AG | null | We present a purely algebraic proof of the commutativity of the operation
defined by intersection with divisors on the Chow group of a local Noetherian
domain.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 14:56:29 GMT"
},
{
"version": "v2",
"created": "Sun, 30 Dec 2007 20:37:08 GMT"
}
] | 2008-01-02T00:00:00 | [
[
"Roberts",
"Paul",
""
],
[
"Spiroff",
"Sandra",
""
]
] |
0707.0433 | D. Levkov | D.G. Levkov, A.G. Panin, S.M. Sibiryakov | Unstable Semiclassical Trajectories in Tunneling | Journal version; 4 pages, 2 figures | Phys.Rev.Lett.99:170407,2007 | 10.1103/PhysRevLett.99.170407 | CERN-PH-TH/2007-109 | quant-ph cond-mat.stat-mech hep-th math-ph math.MP nlin.CD physics.chem-ph | null | Some tunneling phenomena are described, in the semiclassical approximation,
by unstable complex trajectories. We develop a systematic procedure to
stabilize the trajectories and to calculate the tunneling probability,
including both the suppression exponent and prefactor. We find that the
instability of tunneling solutions modifies the power-law dependence of the
prefactor on h as compared to the case of stable solutions.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:01:23 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Nov 2007 10:17:42 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Levkov",
"D. G.",
""
],
[
"Panin",
"A. G.",
""
],
[
"Sibiryakov",
"S. M.",
""
]
] |
0707.0434 | Michiel de Bondt | Michiel de Bondt | Another generalization of Mason's ABC-theorem | 26 pages, new corrections and clarifications, especially in section 4 | null | null | null | math.NT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show a generalization of Mason's ABC-theorem, with the only conditions
that the greatest common divisor has been divided out and no proper subsum of
the (possibly multivariate) polynomial sum f_1 + f_2 + ... + f_n = 0 vanishes.
As a result, we show that the generalized Fermat-Catalan equation for
polynomials: g_1^{d_1} + g_1^{d_2} + ... + g_n^{d_n} = 0 has no non-constant
solutions if the greatest common divisor of the terms equals one, no proper
subsum vanishes and the hyperbolic sum 1/d_1 + 1/d_2 + ... + 1/d_n is at most
1/(n-2). Furthermore, we show that the generalized Fermat-equation for
polynomials g_1^d + g_1^d + ... + g_n^d = 0 has no 'interesting' solutions if d
>= n(n-2).
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:04:18 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Jun 2009 22:25:38 GMT"
},
{
"version": "v3",
"created": "Mon, 17 Jul 2023 15:30:47 GMT"
}
] | 2023-07-21T00:00:00 | [
[
"de Bondt",
"Michiel",
""
]
] |
0707.0435 | Albrecht Bartels | Albrecht Bartels, Raphael Gebs, Matt Kirchner, Scott A. Diddams | Spectrally resolved optical frequency comb from a self-referenced 5 GHz
femtosecond laser | null | null | 10.1364/OL.32.002553 | null | physics.optics physics.atom-ph | null | We report a mode-locked Ti:sapphire femtosecond laser with 5GHz repetition
rate. Spectral broadening of the 24 fs pulses in a microstructured fiber yields
an octave-spanning spectrum and permits self-referencing and active
stabilization of the emitted femtosecond laser frequency comb (FLFC). The
individual modes of the 5GHz FLFC are resolved with a high-resolution
spectrometer based on a virtually imaged phased array (VIPA) spectral
disperser. Isolation of single comb elements at a microwatt average power level
is demonstrated. The combination of the high-power, frequency-stabilized 5GHz
laser and the straightforward resolution of its many modes will benefit
applications in direct frequency comb spectroscopy. Additionally, such a
stabilized FLFC should serve as a useful tool for direct mode-by-mode Fourier
synthesis of arbitrary optical waveforms.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:05:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bartels",
"Albrecht",
""
],
[
"Gebs",
"Raphael",
""
],
[
"Kirchner",
"Matt",
""
],
[
"Diddams",
"Scott A.",
""
]
] |
0707.0436 | Nicolas Borghini | Nicolas Borghini | Multiparticle correlations and momentum conservation in nucleus-nucleus
collisions | 9 pages, talk given at the workshop "High-pT physics at LHC", March
23-27, 2007, Jyvaskyla, Finland. v2: final version | PoSLHC07:013,2007 | null | BI-TP 2007/15 | nucl-th | null | Particle correlations are very actively studied in heavy-ion collisions at
ultra-relativistic energies. Here, an attempt is made at determining a proper
reference for such studies, by taking properly into account the multiparticle
correlations induced by the conservation of total momentum in the collisions.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:12:57 GMT"
},
{
"version": "v2",
"created": "Wed, 17 Oct 2007 10:08:29 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Borghini",
"Nicolas",
""
]
] |
0707.0437 | Soroosh Yazdani | S. Yazdani | Modular Abelian Variety of Odd Modular Degree | 44 Pages, Ph.D. Thesis | null | null | null | math.NT | null | We will study modular Abelian varieties with odd congruence numbers, by
studying the cuspidal subgroup of $J_0(N)$. We show the conductor of such
Abelian varieties must be of a special type, for example if $N$ is odd then
$N=p^\alpha$ or $N=pq$ for some prime $p$ and $q$. We then focus our attention
to modular elliptic curves, and using result of Agashe, Ribet, and Stein, we
try to classify all elliptic curves of odd modular degree. Our studies prove
many cases of the Stein and Watkins's conjecture on elliptic curves with odd
modular degree.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:10:29 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Yazdani",
"S.",
""
]
] |
0707.0438 | Robert Belleman | Robert G. Belleman (1), Jeroen Bedorf (1), Simon Portegies Zwart (1)
((1) UvA) | High Performance Direct Gravitational N-body Simulations on Graphics
Processing Units -- II: An implementation in CUDA | Accepted for publication in New Astronomy | NewAstron.13:103-112,2008 | 10.1016/j.newast.2007.07.004 | null | astro-ph physics.comp-ph | null | We present the results of gravitational direct $N$-body simulations using the
Graphics Processing Unit (GPU) on a commercial NVIDIA GeForce 8800GTX designed
for gaming computers. The force evaluation of the $N$-body problem is
implemented in ``Compute Unified Device Architecture'' (CUDA) using the GPU to
speed-up the calculations. We tested the implementation on three different
$N$-body codes: two direct $N$-body integration codes, using the 4th order
predictor-corrector Hermite integrator with block time-steps, and one
Barnes-Hut treecode, which uses a 2nd order leapfrog integration scheme. The
integration of the equations of motions for all codes is performed on the host
CPU.
We find that for $N > 512$ particles the GPU outperforms the GRAPE-6Af, if
some softening in the force calculation is accepted. Without softening and for
very small integration time steps the GRAPE still outperforms the GPU. We
conclude that modern GPUs offer an attractive alternative to GRAPE-6Af special
purpose hardware. Using the same time-step criterion, the total energy of the
$N$-body system was conserved better than to one in $10^6$ on the GPU, only
about an order of magnitude worse than obtained with GRAPE-6Af. For $N \apgt
10^5$ the 8800GTX outperforms the host CPU by a factor of about 100 and runs at
about the same speed as the GRAPE-6Af.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:16:33 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 10:05:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Belleman",
"Robert G.",
"",
"UvA"
],
[
"Bedorf",
"Jeroen",
"",
"UvA"
],
[
"Zwart",
"Simon Portegies",
"",
"UvA"
]
] |
0707.0439 | Alberto Imparato | A. Imparato, L. Peliti, G. Pesce, G. Rusciano and A. Sasso | Work and heat probability distribution of an optically driven Brownian
particle: Theory and experiments | null | PHYSICAL REVIEW E 76, 050101R (2007) | 10.1103/PhysRevE.76.050101 | null | cond-mat.stat-mech cond-mat.soft | null | We analyze the equations governing the evolution of distributions of the work
and the heat exchanged with the environment by a manipulated stochastic system,
by means of a compact and general derivation. We obtain explicit solutions for
these equations for the case of a dragged Brownian particle in a harmonic
potential. We successfully compare the resulting predictions with the outcomes
of experiments, consisting in dragging a micron-sized colloidal particle
through water with a laser trap.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:25:47 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 15:28:16 GMT"
},
{
"version": "v3",
"created": "Tue, 13 Nov 2007 19:41:48 GMT"
}
] | 2007-11-13T00:00:00 | [
[
"Imparato",
"A.",
""
],
[
"Peliti",
"L.",
""
],
[
"Pesce",
"G.",
""
],
[
"Rusciano",
"G.",
""
],
[
"Sasso",
"A.",
""
]
] |
0707.0440 | Michael Wilczek | M. Wilczek, F. Jenko, R. Friedrich | Lagrangian Particle Statistics in Turbulent Flows from a Simple Vortex
Model | null | null | 10.1103/PhysRevE.77.056301 | null | physics.flu-dyn | null | The statistics of Lagrangian particles in turbulent flows is considered in
the framework of a simple vortex model. Here, the turbulent velocity field is
represented by a temporal sequence of Burgers vortices of different
circulation, strain, and orientation. Based on suitable assumptions about the
vortices' statistical properties, the statistics of the velocity increments is
derived. In particular, the origin and nature of small-scale intermittency in
this model is investigated both numerically and analytically.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:27:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wilczek",
"M.",
""
],
[
"Jenko",
"F.",
""
],
[
"Friedrich",
"R.",
""
]
] |
0707.0441 | Luis Santos | M. Klawunn, R. Nath, P. Pedri and L. Santos | Kelvon-roton instability of vortex lines in dipolar Bose-Einstein
condensates | 4 pages, 3 eps figures | null | 10.1103/PhysRevLett.101.099901 | null | cond-mat.other | null | The physics of vortex lines in dipolar condensates is studied. Due to the
nonlocality of the dipolar interaction, the 3D character of the vortex plays a
more important role in dipolar gases than in typical short-range interacting
ones. In particular, the dipolar interaction significantly affects the
stability of the transverse modes of the vortex line. Remarkably, in the
presence of a periodic potential along the vortex line, a roton minimum may
develop in the spectrum of transverse modes. We discuss the appropriate
conditions at which this roton minimum may eventually lead to an instability of
the straight vortex line, opening new scenarios for vortices in dipolar gases.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:28:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Klawunn",
"M.",
""
],
[
"Nath",
"R.",
""
],
[
"Pedri",
"P.",
""
],
[
"Santos",
"L.",
""
]
] |
0707.0442 | Pierre van Moerbeke | Mark Adler, Jonathan Delepine and Pierre van Moerbeke | Dyson's non-intersecting Brownian motions with a few outliers | 66 pages. This new version contains an improved statement of Theorem
0.1. It also corrects a number of minor misprints | Communication on Pure and Applied Mathematics, 62, issue 3,
334-395 (2009) | null | null | math.PR math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Consider n non-intersecting particles on the real line (Dyson Brownian
motions), all starting from the origin at time=0, and forced to return to x=0
at time=1. For large n, the average mean density of particles has its support,
for each 0<t<1, within the interior of an ellipse. The Airy process is defined
as the motion of these non-intersecting Brownian motions for large n, but
viewed from an arbitrary point on the ellipse with an appropriate space-time
rescaling. Assume now a finite number r of these particles are forced to a
different target point. Does it affect the Brownian fluctuations along the
ellipse for large n? In this paper, we show that no new process appears as long
as one considers points on the ellipse, for which the t-coordinate is smaller
than the t-coordinate of the point of tangency of the tangent to the curve
passing through the target point. At this point of tangency the fluctuations
obey a new statistics: the Airy process with r outliers (in short: {\bf r-Airy
process}). The log of the transition probability of this new process is given
by the Fredholm determinant of a new kernel (extending the Airy kernel) and it
satisfies a non-linear PDE in x and the time.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:30:55 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Nov 2008 23:27:51 GMT"
}
] | 2008-11-20T00:00:00 | [
[
"Adler",
"Mark",
""
],
[
"Delepine",
"Jonathan",
""
],
[
"van Moerbeke",
"Pierre",
""
]
] |
0707.0443 | Annekathrin M\"uller-Lohmann | Annekathrin M\"uller-Lohmann | On a possible interpretation of fusion in Stochastic Loewner Evolution | 7 pages, completely revised version | null | null | ITP-UH-13/07 | hep-th math-ph math.MP | null | We suggest how to give a physical interpretation of Stochastic Loewner
Evolution traces approaching a marked point in the upper half plane. We show
that this may be related to the fusion of boundary with bulk fields in
Conformal Field Theory by taking a look at the probability of such an event.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:31:03 GMT"
},
{
"version": "v2",
"created": "Fri, 25 Jan 2008 10:08:40 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Müller-Lohmann",
"Annekathrin",
""
]
] |
0707.0444 | Sadi Turgut | S. Turgut | Necessary and Sufficient Conditions for the Trumping Relation | 9 pages; comments appreciated; (this article is a corrected and
modified version, which combines this preprint with arXiv:0706.3654) | J. Phys. A: Math. Theor. 40 (2007) 12185-12212 | 10.1088/1751-8113/40/40/012 | null | quant-ph | null | Entanglement catalysis allows one to convert certain entangled states into
others by the temporary involvement of another entangled state (so-called
catalyst), where after the conversion the catalyst is returned to the same
state. For bipartite pure entangled states that can be transformed in this way
with unit probability, the respective Schmidt coefficients are said to satisfy
the trumping relation, a mathematical relation which is an extension of the
majorization relation. This article provides all necessary and sufficient
conditions for the trumping relation in terms of the Schmidt coefficients. The
coefficients should satisfy strict inequalities for the entropy of entanglement
and for power means excluding the special power 1.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:33:47 GMT"
}
] | 2007-09-19T00:00:00 | [
[
"Turgut",
"S.",
""
]
] |
0707.0445 | Nicolas Savy | Laurent Decreusefond, Nicolas Savy | Rubinstein distance on configurations spaces | 9 pages | null | null | null | math.PR | null | By a method inspired of the Stein's method, we derive an upper-bound of the
Rubinstein distance between two absolutely continuous probability measures on
configurations space. As an application, we show that the best way to
approximate a Modulated Poisson Process (see below for the definition) by a
Poisson process is to equate their intensity.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:34:25 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Decreusefond",
"Laurent",
""
],
[
"Savy",
"Nicolas",
""
]
] |
0707.0446 | Alan Cornell | S. Rai Choudhury, A. S. Cornell and Naveen Gaur | $B \to K_1(1270) (\to \rho K) \ell^+ \ell^-$ in LEET | 13 pages, 4 figures | Eur.Phys.J.C58:251-259,2008 | 10.1140/epjc/s10052-008-0752-x | null | hep-ph | null | Flavour Changing Neutral Current decays of the $B$-meson are a very useful
tool for studying possible physics scenarios beyond the Standard Model (SM),
where of the many FCNC modes radiative, purely leptonic and semi-leptonic
decays of the $B$-meson are relatively clean tests. Within this context the
BELLE collaboration has searched for the $B \to K_1(1270) \gamma$ process and
provided an upper bound on this decay. In this work we have used this upper
bound in studying the angular coorelations for the related semi-leptonic decay
mode $B \to K_1(1270) (\to \rho K) \ell^+ \ell^-$, where we have used the form
factors that have already been estimated for the $B \to K_1(1270) \gamma$ mode.
Note that the additional form factors that are required were calculated using
the Large Energy Effective Theory (LEET).
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:37:25 GMT"
}
] | 2009-01-01T00:00:00 | [
[
"Choudhury",
"S. Rai",
""
],
[
"Cornell",
"A. S.",
""
],
[
"Gaur",
"Naveen",
""
]
] |
0707.0447 | Jeno Szigeti | Jeno Szigeti and Leon van Wyk | Subrings which are closed with respect to taking the inverse | null | null | null | null | math.RA | null | Let S be a subring of the ring R. We investigate the question of whether S
intersected by U(R) is equal to U(S) holds for the units. In many situations
our answer is positive. There is a special emphasis on the case when R is a
full matrix ring and S is a structural subring of R defined by a reflexive and
transitive relation.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:37:53 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Szigeti",
"Jeno",
""
],
[
"van Wyk",
"Leon",
""
]
] |
0707.0448 | Shinji Okada | S. Okada, G. Beer, H. Bhang, M. Cargnelli, J. Chiba, Seonho Choi, C.
Curceanu, Y. Fukuda, T. Hanaki, R. S. Hayano, M. Iio, T. Ishikawa, S.
Ishimoto, T. Ishiwatari, K. Itahashi, M. Iwai, M. Iwasaki, B. Juh\'asz, P.
Kienle, J. Marton, Y. Matsuda, H. Ohnishi, H. Outa, M. Sato, P. Schmid, S.
Suzuki, T. Suzuki, H. Tatsuno, D. Tomono, E. Widmann, T. Yamazaki, H. Yim, J.
Zmeskal | Precision measurement of the $3d \to 2p$ x-ray energy in kaonic $^4$He | 12 pages, 4 figues, submitted to Physics Letters B | Phys.Lett.B653:387-391,2007 | 10.1016/j.physletb.2007.08.032 | null | nucl-ex | null | We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel
large-area silicon drift x-ray detectors in order to study the low-energy
$\bar{K}$-nucleus strong interaction. The energy of the $3d \to 2p$ transition
was determined to be 6467 $\pm$ 3 (stat) $\pm$ 2 (syst) eV. The resulting
strong-interaction energy-level shift is in agreement with theoretical
calculations, thus eliminating a long-standing discrepancy between theory and
experiment.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:38:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Okada",
"S.",
""
],
[
"Beer",
"G.",
""
],
[
"Bhang",
"H.",
""
],
[
"Cargnelli",
"M.",
""
],
[
"Chiba",
"J.",
""
],
[
"Choi",
"Seonho",
""
],
[
"Curceanu",
"C.",
""
],
[
"Fukuda",
"Y.",
""
],
[
"Hanaki",
"T.",
""
],
[
"Hayano",
"R. S.",
""
],
[
"Iio",
"M.",
""
],
[
"Ishikawa",
"T.",
""
],
[
"Ishimoto",
"S.",
""
],
[
"Ishiwatari",
"T.",
""
],
[
"Itahashi",
"K.",
""
],
[
"Iwai",
"M.",
""
],
[
"Iwasaki",
"M.",
""
],
[
"Juhász",
"B.",
""
],
[
"Kienle",
"P.",
""
],
[
"Marton",
"J.",
""
],
[
"Matsuda",
"Y.",
""
],
[
"Ohnishi",
"H.",
""
],
[
"Outa",
"H.",
""
],
[
"Sato",
"M.",
""
],
[
"Schmid",
"P.",
""
],
[
"Suzuki",
"S.",
""
],
[
"Suzuki",
"T.",
""
],
[
"Tatsuno",
"H.",
""
],
[
"Tomono",
"D.",
""
],
[
"Widmann",
"E.",
""
],
[
"Yamazaki",
"T.",
""
],
[
"Yim",
"H.",
""
],
[
"Zmeskal",
"J.",
""
]
] |
0707.0449 | Remon Cornelisse | R. Cornelisse, D. Steeghs, J. Casares, P.A. Charles, A.D. Barnes, R.I.
Hynes, K. O'Brien | Optical spectroscopy of the low mass X-ray binary GX9+9 | 12 pages, 11 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12193.x | null | astro-ph | null | Phase-resolved medium resolution VLT spectroscopy of the low mass X-ray
binary GX9+9 has revealed narrow CIII emission lines that move in phase
relative to our new estimate of the ephemeris, and show a velocity amplitude of
230+/-35 km/s. We identify the origin of these lines as coming from the surface
of the donor star, thereby providing the first estimate of the mass function of
f(M_1)>=0.22M_sun. Rotational broadening estimates together with assumptions
for the mass donor give 0.07<q<0.35 and 182<K_2<406 km/s. Despite a low mass
ratio, there is no evidence for a superhump in our dataset. Doppler maps of
GX9+9 show the presence of a stream overflow, either in the form of material
flowing downward along the accretion disk rim or in a similar fashion as occurs
in high mass transfer rate cataclysmic variables known as the SW Sex stars.
Finally we note that the Bowen region in GX9+9 is dominated by CIII instead of
NIII emission as has been the case for most other X-ray binaries.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:50:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cornelisse",
"R.",
""
],
[
"Steeghs",
"D.",
""
],
[
"Casares",
"J.",
""
],
[
"Charles",
"P. A.",
""
],
[
"Barnes",
"A. D.",
""
],
[
"Hynes",
"R. I.",
""
],
[
"O'Brien",
"K.",
""
]
] |
0707.0450 | Simon Haas | S. Haas, B. Batlogg, C. Besnard, M. Schiltz, C. Kloc, T. Siegrist | Large Negative Thermal Expansion in Pentacene due to Steric Hindrance | null | Phys. Rev. B 76, 205203 (2007) | 10.1103/PhysRevB.76.205203 | null | cond-mat.mtrl-sci | null | The uniaxial negative thermal expansion in pentacene crystals along $a$ is a
particularity in the series of the oligoacenes, and exeptionally large for a
crystalline solid. Full x-ray structure analysis from 120 K to 413 K reveals
that the dominant thermal motion is a libration of the rigid molecules about
their long axes, modifying the intermolecular angle which describes the
herringbone packing within the layers. This herringbone angle increases with
temperature (by 0.3 -- 0.6$^{\circ}$ per 100 K), and causes an anisotropic
rearrangement of the molecules within the layers, i.e. an expansion in the $b$
direction, and a distinct contraction along $a$. Additionally, a larger
herringbone angle improves the cofacial overlap between adjacent, parallel
molecules, and thus enhances the attractive van der Waals forces.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:47:32 GMT"
}
] | 2007-12-03T00:00:00 | [
[
"Haas",
"S.",
""
],
[
"Batlogg",
"B.",
""
],
[
"Besnard",
"C.",
""
],
[
"Schiltz",
"M.",
""
],
[
"Kloc",
"C.",
""
],
[
"Siegrist",
"T.",
""
]
] |
0707.0451 | Davide Rossini | Davide Rossini, Giuliano Benenti | Robust and efficient generator of almost maximal multipartite
entanglement | 4 pages, 4 figures. Published version | Phys. Rev. Lett. 100, 060501 (2008) | 10.1103/PhysRevLett.100.060501 | null | quant-ph | null | Quantum chaotic maps can efficiently generate pseudo-random states carrying
almost maximal multipartite entanglement, as characterized by the probability
distribution of bipartite entanglement between all possible bipartitions of the
system. We show that such multipartite entanglement is robust, in the sense
that, when realistic noise is considered, distillable entanglement of
bipartitions remains almost maximal up to a noise strength that drops only
polynomially with the number of qubits.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:55:29 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Feb 2008 12:44:50 GMT"
}
] | 2008-02-12T00:00:00 | [
[
"Rossini",
"Davide",
""
],
[
"Benenti",
"Giuliano",
""
]
] |
0707.0452 | Eyo Ita III | Eyo Eyo Ita III | Instanton representation of Plebanski gravity: IX. Hamiltonian
minisuperspace dynamics in undensitized momentum space variables | 18 pages. Background material for revised journal article | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we illustrate the dynamics of the instanton representation in
the description of vacuum GR in minisuperspace for undensitized variables. We
uncover a new class of general solutions in both the degenerate and the
nondegenerate sectors of the theory. Additionally, the individual sectors are
preserved under Hamiltonian evolution. Finally, we present an algorithm for
constructing general solutions by expansion about the isotropic sector.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 15:59:38 GMT"
},
{
"version": "v2",
"created": "Fri, 4 Apr 2008 19:25:25 GMT"
},
{
"version": "v3",
"created": "Mon, 7 Apr 2008 08:28:44 GMT"
},
{
"version": "v4",
"created": "Fri, 31 Jul 2009 08:24:29 GMT"
},
{
"version": "v5",
"created": "Thu, 22 Apr 2010 19:35:49 GMT"
}
] | 2010-04-23T00:00:00 | [
[
"Ita",
"Eyo Eyo",
"III"
]
] |
0707.0453 | Luca Salasnich | L. Salasnich, A. Cetoli, B.A. Malomed, F. Toigo, and L. Reatto | Bose-Einstein condensates under a spatially-modulated transverse
confinement | 10 pages, 10 figures, accepted for publication in Phys. Rev. A | Phys. Rev. A 76, 013623 (2007) | 10.1103/PhysRevA.76.013623 | null | cond-mat.other | null | We derive an effective nonpolynomial Schrodinger equation (NPSE) for
self-repulsive or attractive BEC in the nearly-1D cigar-shaped trap, with the
transverse confining frequency periodically modulated along the axial
direction. Besides the usual linear cigar-shaped trap, where the periodic
modulation emulates the action of an optical lattice (OL), the model may be
also relevant to toroidal traps, where an ordinary OL cannot be created. For
either sign of the nonlinearity, extended and localized states are found, in
the numerical form (using both the effective NPSE and the full 3D
Gross-Pitaevskii equation) and by means of the variational approximation (VA).
The latter is applied to construct ground-state solitons and predict the
collapse threshold in the case of self-attraction. It is shown that numerical
solutions provided by the one-dimensional NPSE are always very close to full 3D
solutions, and the VA yields quite reasonable results too. The transition from
delocalized states to gap solitons, in the first finite bandgap of the linear
spectrum, is examined in detail, for the repulsive and attractive
nonlinearities alike.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:00:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Salasnich",
"L.",
""
],
[
"Cetoli",
"A.",
""
],
[
"Malomed",
"B. A.",
""
],
[
"Toigo",
"F.",
""
],
[
"Reatto",
"L.",
""
]
] |
0707.0454 | George Amariucai | George T. Amariucai, Shuangqing Wei and Rajgopal Kannan | Optimal Strategies for Gaussian Jamming in Block-Fading Channels under
Delay and Power Constraints | Submitted to IEEE Trans. Inform. Theory, June 03, 2007, for review,
This paper has been withdrawn by the authors. A more recent ane more
elaborate version is available at arXiv:0808.3418 | null | null | null | cs.IT math.IT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Without assuming any knowledge on source's codebook and its output signals,
we formulate a Gaussian jamming problem in block fading channels as a
two-player zero sum game. The outage probability is adopted as an objective
function, over which transmitter aims at minimization and jammer aims at
maximization by selecting their power control strategies. Optimal power control
strategies for each player are obtained under both short-term and long-term
power constraints. For the latter case, we first prove the non-existence of a
Nash equilibrium, and then provide a complete solution for both maxmin and
minimax problems. Numerical results demonstrate a sharp difference between the
outage probabilities of the minimax and maxmin solutions.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:09:37 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Sep 2009 15:53:34 GMT"
}
] | 2009-09-28T00:00:00 | [
[
"Amariucai",
"George T.",
""
],
[
"Wei",
"Shuangqing",
""
],
[
"Kannan",
"Rajgopal",
""
]
] |
0707.0455 | Jorge Russo | Roberto Iengo, Jaume Lopez Carballo and Jorge G. Russo | Strings and D-branes in a supersymmetric magnetic flux background | 22 pages. References added | JHEP 0708:047,2007 | 10.1088/1126-6708/2007/08/047 | UB-ECM-PF/07/14 | hep-th | null | We investigate how the presence of RR magnetic $F_{p+2}$ fluxes affects the
energy of classical Dp branes, for specific string theory supersymmetric
backgrounds which are solutions to the leading order in $\alpha'$ including
back-reaction effects. The Dp brane dynamics is found to be similar to the well
known dynamics of particles and strings moving in magnetic fields. We find a
class of BPS solutions which generalize the BPS fundamental strings or BPS
branes with momentum and winding to the case of non-zero magnetic fields.
Remarkably, the interaction with the magnetic fields does not spoil the
supersymmetry of the solution, which turns out to be invariant under four
supersymmetry transformations. We find that magnetic fields can significantly
reduce the energy of some BPS strings and Dp branes, in particular, some
macroscopic Dp branes become light for sufficiently large magnetic fields.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:13:18 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 07:29:57 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Iengo",
"Roberto",
""
],
[
"Carballo",
"Jaume Lopez",
""
],
[
"Russo",
"Jorge G.",
""
]
] |
0707.0456 | Pilar Herreros | Pilar Herreros | Blocking: New examples and properties of products | 10 pages | null | null | null | math.DG math.DS | null | We say that a pair of points x and y is secure if there exist a finite set of
blocking points such that any geodesic between x and y passes through one of
the blocking points. The main point of this paper is to exhibit new examples of
blocking phenomena both in the manifold and the billiard table setting. As an
approach to this, we study if the product of secure configurations (or
manifolds) is also secure.
We introduce the concept of midpoint security that imposes that the geodesic
reaches a blocking point exactly at its midpoint. We prove that products of
midpoint secure configurations are midpoint secure. On the other hand, we give
an example of a compact C^1 surface that contains secure configurations that
are not midpoint secure. This surface provides the first example of an insecure
product of secure configurations, as well as billiard table examples.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:26:35 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Herreros",
"Pilar",
""
]
] |
0707.0457 | Willi Mohring | H. Vogel, W.Mohring | Density of critical points for a Gaussian random function | 11 pages 1 figure, changes in list of references, corrected typos | null | 10.1088/1751-8113/41/2/025210 | null | physics.flu-dyn | null | Critical points of a scalar quantitiy are either extremal points or saddle
points. The character of the critical points is determined by the sign
distribution of the eigenvalues of the Hessian matrix. For a two-dimensional
homogeneous and isotropic random function topological arguments are sufficient
to show that all possible sign combinations are equidistributed or with other
words, the density of the saddle points and extrema agree. This argument breaks
down in three dimensions. All ratios of the densities of saddle points and
extrema larger than one are possible. For a homogeneous Gaussian random field
one finds no longer an equidistribution of signs, saddle points are slightly
more frequent.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:26:51 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Aug 2007 15:32:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vogel",
"H.",
""
],
[
"Mohring",
"W.",
""
]
] |
0707.0458 | Astrakharchik Grigori E | G.E. Astrakharchik, R. Combescot, L.P. Pitaevskii | Number fluctuations in cold quantum gases | Minor changes due to referee comments | Phys. Rev. A 76, 063616 (2007) | 10.1103/PhysRevA.76.063616 | null | cond-mat.stat-mech | null | In ultracold gases many experiments use atom imaging as a basic observable.
The resulting image is averaged over a number of realizations and mostly only
this average is used. Only recently the noise has been measured to extract
physical information. In the present paper we investigate the quantum noise
arising in these gases at zero temperature. We restrict ourselves to the
homogeneous situation and study the fluctuations in particle number found
within a given volume in the gas, and more specifically inside a sphere of
radius $R$. We show that zero-temperature fluctuations are not extensive and
the leading term scales with sphere radius $R$ as $R^2\ln R$ (or $\ln R$) in
three- (or one-) dimensional systems. We calculate systematically the next term
beyond this leading order. We consider first the generic case of a compressible
superfluid. Then we investigate the whole Bose-Einstein-condensation (BEC)-BCS
crossover crossover, and in particular the limiting cases of the weakly
interacting Bose gas and of the free Fermi gas.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:31:23 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Dec 2007 18:10:56 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Astrakharchik",
"G. E.",
""
],
[
"Combescot",
"R.",
""
],
[
"Pitaevskii",
"L. P.",
""
]
] |
0707.0459 | Petar Popovski | Petar Popovski and Hiroyuki Yomo | Physical Network Coding in Two-Way Wireless Relay Channels | null | Proc. of IEEE International Conference on Communications (ICC),
Glasgow, Scotland, 2007 | null | null | cs.IT cs.NI math.IT | null | It has recently been recognized that the wireless networks represent a
fertile ground for devising communication modes based on network coding. A
particularly suitable application of the network coding arises for the two--way
relay channels, where two nodes communicate with each other assisted by using a
third, relay node. Such a scenario enables application of \emph{physical
network coding}, where the network coding is either done (a) jointly with the
channel coding or (b) through physical combining of the communication flows
over the multiple access channel. In this paper we first group the existing
schemes for physical network coding into two generic schemes, termed 3--step
and 2--step scheme, respectively. We investigate the conditions for
maximization of the two--way rate for each individual scheme: (1) the
Decode--and--Forward (DF) 3--step schemes (2) three different schemes with two
steps: Amplify--and--Forward (AF), JDF and Denoise--and--Forward (DNF). While
the DNF scheme has a potential to offer the best two--way rate, the most
interesting result of the paper is that, for some SNR configurations of the
source--relay links, JDF yields identical maximal two--way rate as the upper
bound on the rate for DNF.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:40:41 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Popovski",
"Petar",
""
],
[
"Yomo",
"Hiroyuki",
""
]
] |
0707.0460 | Alexis Gagnon Morris | Alexis G. Morris, David L. Feder | Gaussian potentials facilitate access to quantum Hall states in rotating
Bose gases | 4 pages, 4 figures | Phys. Rev. Lett. 99, 240401 (2007) | 10.1103/PhysRevLett.99.240401 | null | cond-mat.mes-hall | null | Through exact numerical diagonalization for small numbers of atoms, we show
that it is possible to access quantum Hall states in harmonically confined Bose
gases at rotation frequencies well below the centrifugal limit by applying a
repulsive Gaussian potential at the trap center. The main idea is to reduce or
eliminate the effective trapping frequency in regions where the particle
density is appreciable. The critical rotation frequency required to obtain the
bosonic Laughlin state can be fixed at an experimentally accessible value by
choosing an applied Gaussian whose amplitude increases linearly with the number
of atoms while its width increases as the square root.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:37:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Morris",
"Alexis G.",
""
],
[
"Feder",
"David L.",
""
]
] |
0707.0461 | Simon Haas | S. Haas, A. F. Stassen, G. Schuck, K. P. Pernstich, D. J. Gundlach, B.
Batlogg, U. Berens, H.-J. Kirner | High charge-carrier mobility and low trap density in a rubrene
derivative | null | Phys. Rev. B 76, 115203 (2007) | 10.1103/PhysRevB.76.115203 | null | cond-mat.mtrl-sci | null | We have synthesized, crystallized and studied the structural and electric
transport properties of organic molecular crystals based on a rubrene
derivative with {\em t}-butyl sidegroups at the 5,11 positions. Two crystalline
modifications are observed: one (A) distinct from that of rubrene with larger
spacings between the naphtacene backbones, the other (B) with a in-plane
structure presumably very similar compared to rubrene. The electric transport
properties reflect the different structures: in the latter phase (B) the
in-plane hole mobility of 12 cm$^2$/Vs measured on single crystal FETs is just
as high as in rubrene crystals, while in the A phase no field-effect could be
measured. The high crystal quality, studied in detail for B, reflects itself in
the density of gap states: The deep-level trap density as low as $10^{15}$
cm$^{-3}$ eV$^{-1}$ has been measured, and an exponential band tail with a
characteristic energy of 22 meV is observed. The bulk mobility perpendicular to
the molecular planes is estimated to be of order of $10^{-3}$ -- $10^{-1}$
cm$^2$/Vs.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:48:43 GMT"
}
] | 2007-12-03T00:00:00 | [
[
"Haas",
"S.",
""
],
[
"Stassen",
"A. F.",
""
],
[
"Schuck",
"G.",
""
],
[
"Pernstich",
"K. P.",
""
],
[
"Gundlach",
"D. J.",
""
],
[
"Batlogg",
"B.",
""
],
[
"Berens",
"U.",
""
],
[
"Kirner",
"H. -J.",
""
]
] |
0707.0462 | Jason A. Osborne | Jason A. Osborne and Tony E. Grift | M-estimation of Boolean models for particle flow experiments | null | null | null | null | stat.AP | null | Probability models are proposed for passage time data collected in
experiments with a device designed to measure particle flow during aerial
application of fertilizer. Maximum likelihood estimation of flow intensity is
reviewed for the simple linear Boolean model, which arises with the assumption
that each particle requires the same known passage time. M-estimation is
developed for a generalization of the model in which passage times behave as a
random sample from a distribution with a known mean. The generalized model
improves fit in these experiments. An estimator of total particle flow is
constructed by conditioning on lengths of multi-particle clumps.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:55:01 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Osborne",
"Jason A.",
""
],
[
"Grift",
"Tony E.",
""
]
] |
0707.0463 | Yuanning Yu | Yuanning Yu, Athina P. Petropulu, H. Vincent Poor and Visa Koivunen | Blind Estimation of Multiple Carrier Frequency Offsets | To appear in the Proceedings of the 18th Annual IEEE International
Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC),
Athens, Greece, September 3-7, 2007 | null | 10.1109/PIMRC.2007.4394103 | null | cs.IT math.IT | null | Multiple carrier-frequency offsets (CFO) arise in a distributed antenna
system, where data are transmitted simultaneously from multiple antennas. In
such systems the received signal contains multiple CFOs due to mismatch between
the local oscillators of transmitters and receiver. This results in a
time-varying rotation of the data constellation, which needs to be compensated
for at the receiver before symbol recovery. This paper proposes a new approach
for blind CFO estimation and symbol recovery. The received base-band signal is
over-sampled, and its polyphase components are used to formulate a virtual
Multiple-Input Multiple-Output (MIMO) problem. By applying blind MIMO system
estimation techniques, the system response is estimated and used to
subsequently transform the multiple CFOs estimation problem into many
independent single CFO estimation problems. Furthermore, an initial estimate of
the CFO is obtained from the phase of the MIMO system response. The Cramer-Rao
Lower bound is also derived, and the large sample performance of the proposed
estimator is compared to the bound.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 16:58:43 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Yu",
"Yuanning",
""
],
[
"Petropulu",
"Athina P.",
""
],
[
"Poor",
"H. Vincent",
""
],
[
"Koivunen",
"Visa",
""
]
] |
0707.0464 | Thomas Gautier III | Thomas. N. Gautier III, G. H. Rieke, John Stansberry, Geoffrey C.
Bryden, Karl R. Stapelfeldt, Michael W. Werner, Charles A. Beichman,
Christine Chen, Kate Su, David Trilling, Brian M. Patten and Thomas L.
Roellig | Far Infrared Prperties of M Dwarfs | 28 pages, 4 figures, to be published in The Astrophysical Journal | Astrophys.J.667:527-536,2007 | 10.1086/520667 | null | astro-ph | null | We report the mid- and far-infrared properties of nearby M dwarfs.
Spitzer/MIPS measurements were obtained for a sample of 62 stars at 24 um, with
subsamples of 41 and 20 stars observed at 70 um and 160 um respectively. We
compare the results with current models of M star photospheres and look for
indications of circumstellar dust in the form of significant deviations of
K-[24 um] colors and 70 um / 24 um flux ratios from the average M star values.
At 24 um, all 62 of the targets were detected; 70 um detections were achieved
for 20 targets in the subsample observed; and no detections were seen in the
160 um subsample. No clear far-infrared excesses were detected in our sample.
The average far infrared excess relative to the photospheric emission of the M
stars is at least four times smaller than the similar average for a sample of
solar-type stars. However, this limit allows the average fractional infrared
luminosity in the M-star sample to be similar to that for more massive stars.
We have also set low limits for the maximum mass of dust possible around our
stars.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 17:47:05 GMT"
}
] | 2009-12-08T00:00:00 | [
[
"Gautier",
"Thomas. N.",
"III"
],
[
"Rieke",
"G. H.",
""
],
[
"Stansberry",
"John",
""
],
[
"Bryden",
"Geoffrey C.",
""
],
[
"Stapelfeldt",
"Karl R.",
""
],
[
"Werner",
"Michael W.",
""
],
[
"Beichman",
"Charles A.",
""
],
[
"Chen",
"Christine",
""
],
[
"Su",
"Kate",
""
],
[
"Trilling",
"David",
""
],
[
"Patten",
"Brian M.",
""
],
[
"Roellig",
"Thomas L.",
""
]
] |
0707.0465 | Benny Sudakov | Tom Bohman, Alan Frieze and Benny Sudakov | The game chromatic number of random graphs | null | null | null | null | math.CO | null | Given a graph G and an integer k, two players take turns coloring the
vertices of G one by one using k colors so that neighboring vertices get
different colors. The first player wins iff at the end of the game all the
vertices of G are colored. The game chromatic number \chi_g(G) is the minimum k
for which the first player has a winning strategy. In this paper we analyze the
asymptotic behavior of this parameter for a random graph G_{n,p}. We show that
with high probability the game chromatic number of G_{n,p} is at least twice
its chromatic number but, up to a multiplicative constant, has the same order
of magnitude. We also study the game chromatic number of random bipartite
graphs.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 17:29:09 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Bohman",
"Tom",
""
],
[
"Frieze",
"Alan",
""
],
[
"Sudakov",
"Benny",
""
]
] |
0707.0466 | Igor Luk'yanchuk A | Igor A. Luk'yanchuk, Alexander M. Bratkovsky | Lattice-Induced Double-Valley Degeneracy Lifting in Magnetic Field in
Graphene | null | null | 10.1103/PhysRevLett.100.176404 | null | cond-mat.mes-hall | null | We show that the recently discovered double-valley splitting of the low-lying
Landau level(s) in the Quantum Hall Effect in graphene can be explained as
perturbative orbital interaction of intra- and inter-valley microscopic orbital
currents with a magnetic field. This effect is provided by the
translational-non-invariant terms corresponding to graphene's crystallographic
honeycomb symmetry but do not exist in the relativistic theory of massless
Dirac Fermions in Quantum Electrodynamics. We discuss recent data in view of
these results.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 17:40:24 GMT"
},
{
"version": "v2",
"created": "Fri, 10 Aug 2007 10:23:20 GMT"
},
{
"version": "v3",
"created": "Tue, 16 Oct 2007 18:51:17 GMT"
},
{
"version": "v4",
"created": "Fri, 7 Dec 2007 13:46:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Luk'yanchuk",
"Igor A.",
""
],
[
"Bratkovsky",
"Alexander M.",
""
]
] |
0707.0467 | Daniela Calzetti | Daniela Calzetti (Dept of Astronomy, UMass) | Star Formation Rate Determinations | 12 pages, 4 figures; to appear in the Proceedings of the conference
`Pathways through an Eclectic Universe', J.H. Knapen, T.J. Mahoney, and A.
Vazdekis eds., ASP Conference Serries, 2007 | null | null | null | astro-ph | null | I review determinations of star formation rates (SFR) from the ultraviolet to
the infrared, in the context of their use for galaxies and galaxy surveys. The
mid-infrared SFR indicators have garnered interest in recent years thanks to
the Spitzer capabilities and the opportunities offered by the upcoming Herschel
Space Telescope. I discuss what we have learned in the mid-infrared from
studies of local galaxies combining Spitzer with HST and other data.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 17:50:14 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Calzetti",
"Daniela",
"",
"Dept of Astronomy, UMass"
]
] |
0707.0468 | Tuan Do | Tuan Do (1), Mark Morris (1), Raghvendra Sahai (2) and Karl
Stapelfeldt (2) ((1) University of California, Los Angeles, (2) JPL, Caltech) | A Spitzer Study of the Mass Loss Histories of Three Bipolar
Pre-Planetary Nebulae | 31 pages, 12 figures, accepted to AJ | Astron.J.134:1419-1431,2007 | 10.1086/521553 | null | astro-ph | null | We present the results of far-infrared imaging of extended regions around
three bipolar pre-planetary nebulae, AFGL 2688, OH 231.8+4.2, and IRAS
16342$-$3814, at 70 and 160 $\mu$m with the MIPS instrument on the Spitzer
Space Telescope. After a careful subtraction of the point spread function of
the central star from these images, we place constraints on the existence of
extended shells and thus on the mass outflow rates as a function of radial
distance from these stars. We find no apparent extended emission in AFGL 2688
and OH 231.8+4.2 beyond 100 arcseconds from the central source. In the case of
AFGL 2688, this result is inconsistent with a previous report of two extended
dust shells made on the basis of ISO observations. We derive an upper limit of
$2.1\times10^{-7}$ M$_\odot$ yr$^{-1}$ and $1.0\times10^{-7}$ M$_\odot$
yr$^{-1}$ for the dust mass loss rate of AFGL 2688 and OH 231.8, respectively,
at 200 arcseconds from each source. In contrast to these two sources, IRAS
16342$-$3814 does show extended emission at both wavelengths, which can be
interpreted as a very large dust shell with a radius of $\sim$ 400 arcseconds
and a thickness of $\sim$ 100 arcseconds, corresponding to 4 pc and 1 pc,
respectively, at a distance of 2 kpc. However, this enhanced emission may also
be galactic cirrus; better azimuthal coverage is necessary for confirmation of
a shell. If the extended emission is a shell, it can be modeled as enhanced
mass outflow at a dust mass outflow rate of $1.5\times10^{-6}$ M$_\odot$
yr$^{-1}$ superimposed on a steady outflow with a dust mass outflow rate of
$1.5\times10^{-7}$ M$_\odot$ yr$^{-1}$. It is likely that this shell has swept
up a substantial mass of interstellar gas during its expansion, so these
estimates are upper limits to the stellar mass loss rate.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:10:34 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Do",
"Tuan",
"",
"University of California, Los Angeles"
],
[
"Morris",
"Mark",
"",
"University of California, Los Angeles"
],
[
"Sahai",
"Raghvendra",
"",
"JPL, Caltech"
],
[
"Stapelfeldt",
"Karl",
"",
"JPL, Caltech"
]
] |
0707.0469 | Sara Ricciardi | A. Bonaldi (1,2), S. Ricciardi (1), S. Leach (3), F. Stivoli (3), C.
Baccigalupi (3), G. De Zotti (1) ((1)INAF -Astronomical Observatory of Padova
(2)University of Padova, Astronomy (3)SISSA/ISAS, Astrophysics) | WMAP 3yr data with the CCA: anomalous emission and impact of component
separation on the CMB power spectrum | 14 pages, 17 figures, submitted to MNRAS, references added | MNRAS, Volume 382, Issue 4, (2007) pp. 1791-1803 | 10.1111/j.1365-2966.2007.12477.x | null | astro-ph | null | The Correlated Component Analysis (CCA) allows us to estimate how the
different diffuse emissions mix in CMB experiments, exploiting also
complementary information from other surveys. It is especially useful to deal
with possible additional components. An application of CCA to WMAP maps
assuming that only the canonical Galactic emissions are present, highlights the
widespread presence of a spectrally flat "synchrotron" component, largely
uncorrelated with the synchrotron template, suggesting that an additional
foreground is indeed required. We have tested various spectral shapes for such
component, namely a power law as expected if it is flat synchrotron, and two
spectral shapes that may fit the spinning dust emission: a parabola in the logS
- log(frequency) plane, and a grey body. Quality tests applied to the
reconstructed CMB maps clearly disfavour two of the models. The CMB power
spectra, estimated from CMB maps reconstructed exploiting the three surviving
foreground models, are generally consistent with the WMAP ones, although at
least one of them gives a significantly higher quadrupole moment than found by
the WMAP team. Taking foreground modeling uncertainties into account, we find
that the mean quadrupole amplitude for the three "good" models is less than 1
sigma below the expectation from the standard LambdaCDM model. Also the other
reported deviations from model predictions are found not to be statistically
significant, except for the excess power at l~40. We confirm the evidence for a
marked North-South asymmetry in the large scale (l < 20) CMB anisotropies. We
also present a first, albeit preliminary, all-sky map of the "anomalous"
component.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:22:43 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 12:39:52 GMT"
}
] | 2009-01-13T00:00:00 | [
[
"Bonaldi",
"A.",
""
],
[
"Ricciardi",
"S.",
""
],
[
"Leach",
"S.",
""
],
[
"Stivoli",
"F.",
""
],
[
"Baccigalupi",
"C.",
""
],
[
"De Zotti",
"G.",
""
]
] |
0707.0470 | Shmatov Sergei | Sergei Shmatov | Search for Extra Dimensions with Atlas and CMS Detectors at the LHC | The talk given at the XXXIII International Conference on High Energy
Physics (ICHEP'06) on behalf of the ATLAS and CMS Collaborations, July 26
-August 02, 2006, Moscow, Russia | null | 10.1142/9789812790873_0246 | null | hep-ex | null | A brief review of the discovery potential of the ATLAS and CMS experiments to
search for signals from extra dimensions in different luminosity scenarios is
given.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:24:43 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Shmatov",
"Sergei",
""
]
] |
0707.0471 | Francesco Villante | F.L. Villante, F. Vissani | Method to extract the primary cosmic ray spectrum from very high energy
gamma-ray data and its application to SNR RX J1713.7-3946 | 20 pages, 6 figures, version accepted for publication in Phys.ReV.D | Phys.Rev.D76:125019,2007 | 10.1103/PhysRevD.76.125019 | null | astro-ph | null | Supernova remnants are likely to be the accelerators of the galactic cosmic
rays. Assuming the correctness of this hypothesis, we develop a method to
extract the parent cosmic ray spectrum from the VHE gamma ray flux emitted by
supernova remnants (and other gamma transparent sources). Namely, we calculate
semi-analytically the (inverse) operator which relates an arbitrary gamma ray
flux to the parent cosmic ray spectrum, without relying on any theoretical
assumption about the shape of the cosmic ray and/or photon spectrum. We
illustrate the use of this technique by applying it to the young SNR RX
J1713.7-3946 which has been observed by H.E.S.S. experiment during the last
three years. Specific implementations of the method permit to use as an input
either the parameterized VHE gamma ray flux or directly the raw data. The
possibility to detect features in the cosmic rays spectrum and the error in the
determination of the parent cosmic ray spectrum are also discussed.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:33:13 GMT"
},
{
"version": "v2",
"created": "Wed, 18 Jul 2007 13:09:55 GMT"
},
{
"version": "v3",
"created": "Fri, 4 Jan 2008 10:03:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Villante",
"F. L.",
""
],
[
"Vissani",
"F.",
""
]
] |
0707.0472 | Viktor Zacek | Viktor Zacek | Dark Matter | Proc. of the 2007 Lake Louise Winter Institute, March 2007; 14 pages,
13 figures | null | 10.1142/9789812776105_0007 | null | astro-ph hep-ex | null | The nature of the main constituents of the mass of the universe is one of the
outstanding riddles of cosmology and astro-particle physics. Current models
explaining the evolution of the universe, and measurements of the various
components of its mass, all have in common that an appreciable contribution to
that mass is non-luminous and non-baryonic, and that a large fraction of this
so-called dark matter must be in the form of non-relativistic massive particles
(Cold Dark Matter: CDM). In the spirit of the Lake Louise Winter Institute
Lectures we take a look at the latest astronomical discoveries and report on
the status of direct and indirect Dark Matter searches.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:53:06 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Zacek",
"Viktor",
""
]
] |
0707.0473 | Raul Rossignoli | R. Rossignoli, C.T. Schmiegelow | Entanglement generation resonances in XY chains | null | Physical Review A 75, 012320 (2007) | 10.1103/PhysRevA.75.012320 | null | quant-ph | null | We examine the maximum entanglement reached by an initially fully aligned
state evolving in an XY Heisenberg spin chain placed in a uniform transverse
magnetic field. Both the global entanglement between one qubit and the rest of
the chain and the pairwise entanglement between adjacent qubits is analyzed. It
is shown that in both cases the maximum is not a monotonous decreasing function
of the aligning field, exhibiting instead a resonant behavior for low
anisotropies, with pronounced peaks (a total of [n/2] peaks in the global
entanglement for an $n$-spin chain), whose width is proportional to the
anisotropy and whose height remains finite in the limit of small anisotropy. It
is also seen that the maximum pairwise entanglement is not a smooth function of
the field even in small finite chains, where it may exhibit narrow peaks above
strict plateaus. Explicit analytical results for small chains, as well as
general exact results for finite n-spin chains obtained through the
Jordan-Wigner mapping, are discussed.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:42:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rossignoli",
"R.",
""
],
[
"Schmiegelow",
"C. T.",
""
]
] |
0707.0474 | Matthew Lister | Matthew L. Lister | Parsec-Scale Jet-Environment Interactions in AGN | 9 pages; to appear in "Extragalactic Jets: Theory and Observation
from Radio to Gamma Ray", eds. T. A. Rector and D. S. De Young, ASP
conference series. Note: replaced version is identical to the original | null | null | null | astro-ph | null | Observations made with the VLBA have led to fundamental advances in our
understanding of how radio jets in AGN evolve from parsec-scales out to
distances exceeding several hundred kiloparsecs. In this review I discuss
current models of young radio source evolution, as well as the observational
evidence for a rapid change in jet properties on scales of ~1 kpc. A central
topic of current debate is the relative importance of intermittent jet fueling
versus jet-environment interactions in causing a drop-off in powerful radio
sources at this critical evolutionary stage. Recent 3-D hydrodynamical jet
simulations suggest that dense environments and cloud collisions can
temporarily stifle, but not completely halt powerful relativistic jets. Several
VLBA studies of jet-ISM interactions in both blazars and weak Seyfert jets have
indicated that collimated outflows are indeed possible in dense environments.
At present, the bulk of the evidence favors intermittent AGN accretion as the
dominant factor in determining the evolutionary path of large numbers of AGN
jets.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:02:56 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 16:24:15 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Lister",
"Matthew L.",
""
]
] |
0707.0475 | James Franson | J.D. Franson | Nonlocal Interferometry: Beyond Bell's Inequality | 13 pages, 16 figures; proceedings of CQO9 | Proceedings of the Ninth Rochester Conference on Coherence and
Quantum Optics, N.P. Bigelow, J.H. Eberly, and C.R. Stroud, Jr., eds.
(Optical Society of America) 178-190 (2008). | null | null | quant-ph | null | This paper presents a tutorial review of nonlocal interferometry. The role of
the Feynman propagator in optical coherence is also discussed, including the
possibility of generating optical coherence and entanglement outside of the
light cone.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:53:55 GMT"
}
] | 2008-07-18T00:00:00 | [
[
"Franson",
"J. D.",
""
]
] |
0707.0476 | Nihar Jindal | Nihar Jindal, Steven Weber, Jeffrey G. Andrews | Fractional Power Control for Decentralized Wireless Networks | 16 pages, in revision for IEEE Trans. on Wireless Communication | null | 10.1109/T-WC.2008.071439 | null | cs.IT math.IT | null | We consider a new approach to power control in decentralized wireless
networks, termed fractional power control (FPC). Transmission power is chosen
as the current channel quality raised to an exponent -s, where s is a constant
between 0 and 1. The choices s = 1 and s = 0 correspond to the familiar cases
of channel inversion and constant power transmission, respectively. Choosing s
in (0,1) allows all intermediate policies between these two extremes to be
evaluated, and we see that usually neither extreme is ideal. We derive
closed-form approximations for the outage probability relative to a target SINR
in a decentralized (ad hoc or unlicensed) network as well as for the resulting
transmission capacity, which is the number of users/m^2 that can achieve this
SINR on average. Using these approximations, which are quite accurate over
typical system parameter values, we prove that using an exponent of 1/2
minimizes the outage probability, meaning that the inverse square root of the
channel strength is a sensible transmit power scaling for networks with a
relatively low density of interferers. We also show numerically that this
choice of s is robust to a wide range of variations in the network parameters.
Intuitively, s=1/2 balances between helping disadvantaged users while making
sure they do not flood the network with interference.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:54:05 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Apr 2008 14:44:07 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Jindal",
"Nihar",
""
],
[
"Weber",
"Steven",
""
],
[
"Andrews",
"Jeffrey G.",
""
]
] |
0707.0477 | Oleg Semyonov | Oleg G. Semyonov | Alternative Approach to 3D Displaying | 12 pages, 5 figures | null | null | null | physics.optics physics.ins-det | null | A method for displaying volumetric images, which exploits our binocular
vision and does not require eyewear, is discussed. The display can be rendered
as a matrix of pivoting micromirrors irradiated by a light beam; each
micromirror focuses its pixel beams to the same point of displayed volumetric
image. 3D perception of image can be achieved by scanning the point of beams
intersection over a virtual surface of displayed image in space.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:56:16 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Semyonov",
"Oleg G.",
""
]
] |
0707.0478 | Chetan Nayak | Sung-Sik Lee, Shinsei Ryu, Chetan Nayak, Matthew P.A. Fisher | Particle-Hole Symmetry and the $\nu={5/2}$ Quantum Hall State | arXiv number added to Levin et al. paper | null | 10.1103/PhysRevLett.99.236807 | null | cond-mat.mes-hall | null | We discuss the implications of approximate particle-hole symmetry in a
half-filled Landau level in which a paired quantum Hall state forms. We note
that the Pfaffian state is not particle-hole symmetric. Therefore, in the limit
of vanishing Landau level mixing, in which particle-hole transformation is an
exact symmetry, the Pfaffian spontaneously breaks this symmetry. There is a
particle-hole conjugate state, which we call the anti-Pfaffian, which is
degenerate with the Pfaffian in this limit. We observe that strong Landau level
mixing should favor the Pfaffian, but it is an open problem which state is
favored for the moderate Landau level mixing which is present in experiments.
We discuss the bulk and edge physics of the anti-Pfaffian. We analyze a
simplified model in which transitions between analogs of the two states can be
studied in detail. Finally, we discuss experimental implications.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:58:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lee",
"Sung-Sik",
""
],
[
"Ryu",
"Shinsei",
""
],
[
"Nayak",
"Chetan",
""
],
[
"Fisher",
"Matthew P. A.",
""
]
] |
0707.0479 | Hamidreza Farmanbar | Hamidreza Farmanbar and Amir K. Khandani | Precoding for the AWGN Channel with Discrete Interference | 5 pages, 3 figures, presented at ISIT 2007. In section 2, a new upper
bound is obtained for the cardinality of the auxiliary random variable in the
Shannon's capacity formula for the channel with causal side information at
the encoder | null | null | UW-ECE-2006-24 | cs.IT math.IT | null | For a state-dependent DMC with input alphabet $\mathcal{X}$ and state
alphabet $\mathcal{S}$ where the i.i.d. state sequence is known causally at the
transmitter, it is shown that by using at most
$|\mathcal{X}||\mathcal{S}|-|\mathcal{S}|+1$ out of
$|\mathcal{X}|^{|\mathcal{S}|}$ input symbols of the Shannon's
\emph{associated} channel, the capacity is achievable. As an example of
state-dependent channels with side information at the transmitter, $M$-ary
signal transmission over AWGN channel with additive $Q$-ary interference where
the sequence of i.i.d. interference symbols is known causally at the
transmitter is considered. For the special case where the Gaussian noise power
is zero, a sufficient condition, which is independent of interference, is given
for the capacity to be $\log_2 M$ bits per channel use. The problem of
maximization of the transmission rate under the constraint that the channel
input given any current interference symbol is uniformly distributed over the
channel input alphabet is investigated. For this setting, the general structure
of a communication system with optimal precoding is proposed.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 18:59:11 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Farmanbar",
"Hamidreza",
""
],
[
"Khandani",
"Amir K.",
""
]
] |
0707.0480 | Thomas Joerg | Thomas Jorg, Federico Ricci-Tersenghi | Entropic Effects in the Very Low Temperature Regime of Diluted Ising
Spin Glasses with Discrete Couplings | 4 pages, 4 figures. A major typo error in formula (8) has been
corrected | Phys. Rev. Lett. 100, 177203 (2008) | 10.1103/PhysRevLett.100.177203 | null | cond-mat.dis-nn cond-mat.stat-mech | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study link-diluted $\pm J$ Ising spin glass models on the hierarchical
lattice and on a three-dimensional lattice close to the percolation threshold.
We show that previously computed zero temperature fixed points are unstable
with respect to temperature perturbations and do not belong to any critical
line in the dilution-temperature plane. We discuss implications of the presence
of such spurious unstable fixed points on the use of optimization algorithms,
and we show how entropic effects should be taken into account to obtain the
right physical behavior and critical points.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:00:24 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Apr 2008 12:54:53 GMT"
},
{
"version": "v3",
"created": "Fri, 2 Jan 2009 14:50:37 GMT"
}
] | 2009-01-02T00:00:00 | [
[
"Jorg",
"Thomas",
""
],
[
"Ricci-Tersenghi",
"Federico",
""
]
] |
0707.0481 | Ann Lee | Ann B. Lee, Boaz Nadler, Larry Wasserman | Treelets--An adaptive multi-scale basis for sparse unordered data | This paper commented in: [arXiv:0807.4011], [arXiv:0807.4016],
[arXiv:0807.4018], [arXiv:0807.4019], [arXiv:0807.4023], [arXiv:0807.4024].
Rejoinder in [arXiv:0807.4028]. Published in at
http://dx.doi.org/10.1214/07-AOAS137 the Annals of Applied Statistics
(http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics
(http://www.imstat.org) | Annals of Applied Statistics 2008, Vol. 2, No. 2, 435-471 | 10.1214/07-AOAS137 | IMS-AOAS-AOAS137 | stat.ME | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In many modern applications, including analysis of gene expression and text
documents, the data are noisy, high-dimensional, and unordered--with no
particular meaning to the given order of the variables. Yet, successful
learning is often possible due to sparsity: the fact that the data are
typically redundant with underlying structures that can be represented by only
a few features. In this paper we present treelets--a novel construction of
multi-scale bases that extends wavelets to nonsmooth signals. The method is
fully adaptive, as it returns a hierarchical tree and an orthonormal basis
which both reflect the internal structure of the data. Treelets are especially
well-suited as a dimensionality reduction and feature selection tool prior to
regression and classification, in situations where sample sizes are small and
the data are sparse with unknown groupings of correlated or collinear
variables. The method is also simple to implement and analyze theoretically.
Here we describe a variety of situations where treelets perform better than
principal component analysis, as well as some common variable selection and
cluster averaging schemes. We illustrate treelets on a blocked covariance model
and on several data sets (hyperspectral image data, DNA microarray data, and
internet advertisements) with highly complex dependencies between variables.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:22:35 GMT"
},
{
"version": "v2",
"created": "Fri, 31 Aug 2007 19:19:22 GMT"
},
{
"version": "v3",
"created": "Fri, 25 Jul 2008 08:43:51 GMT"
}
] | 2008-07-25T00:00:00 | [
[
"Lee",
"Ann B.",
""
],
[
"Nadler",
"Boaz",
""
],
[
"Wasserman",
"Larry",
""
]
] |
0707.0482 | Ruslan Sharipov | Ruslan Sharipov | Comparison of two formulas for metric connections in the bundle of Dirac
spinors | AmSTeX, 16 pages, amsppt style | null | null | null | math.DG gr-qc hep-ph hep-th math-ph math.MP | null | Two explicit formulas for metric connections in the bundle of Dirac spinors
are studied. Their equivalence is proved. The explicit formula relating the
spinor curvature tensor with the Riemann curvature tensor is rederived.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:17:22 GMT"
}
] | 2007-09-11T00:00:00 | [
[
"Sharipov",
"Ruslan",
""
]
] |
0707.0483 | Michael Levin | Michael Levin, Bertrand I. Halperin, and Bernd Rosenow | Particle-hole symmetry and the Pfaffian state | 5 pages | Phys. Rev. Lett. 99, 236806 (2007) | 10.1103/PhysRevLett.99.236806 | null | cond-mat.mes-hall cond-mat.str-el | null | We consider the properties of the Moore-Read Pfaffian state under
particle-hole conjugation. We show that the particle-hole conjugate of the
Pfaffian state - or "anti-Pfaffian" state - is in a different universality
class from the Pfaffian state, with different topological order. The two states
can be distinguished by both their bulk and edge physics though the difference
is most dramatic at the edge: the edge of the anti-Pfaffian state has a
composite structure that leads to a different thermal Hall conductance and
different tunneling exponents than the Pfaffian state. At the same time, the
two states are exactly degenerate in energy for a $\nu = 5/2$ quantum Hall
system in the idealized limit of zero Landau level mixing. Thus, both are good
candidates for the observed $\nu = 5/2$ quantum Hall plateau.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:19:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Levin",
"Michael",
""
],
[
"Halperin",
"Bertrand I.",
""
],
[
"Rosenow",
"Bernd",
""
]
] |
0707.0484 | Michael J. Kurtz | Michael J. Kurtz, Margaret J. Geller, Daniel G. Fabricant, William F.
Wyatt, Ian P. Dell'Antonio | $\mu$--PhotoZ: Photometric Redshifts by Inverting the Tolman Surface
Brightness Test | Accepted for publication in the Astronomical Journal | Astron.J.134:1360-1367,2007 | 10.1086/521430 | null | astro-ph | null | Surface brightness is a fundamental observational parameter of galaxies. We
show, for the first time in detail, how it can be used to obtain photometric
redshifts for galaxies, the $\mu$-PhotoZ method.
We demonstrate that the Tolman surface brightness relation, $\mu \propto
(1+z)^{-4}$, is a powerful tool for determining galaxy redshifts from
photometric data.
We develop a model using $\mu$ and a color percentile (ranking) measure to
demonstrate the $\mu$-PhotoZ method. We apply our method to a set of galaxies
from the SHELS survey, and demonstrate that the photometric redshift accuracy
achieved using the surface brightness method alone is comparable with the best
color-based methods.
We show that the $\mu$-PhotoZ method is very effective in determining the
redshift for red galaxies using only two photometric bands. We discuss the
properties of the small, skewed, non-gaussian component of the error
distribution.
We calibrate $\mu_r, (r-i)$ from the SDSS to redshift, and tabulate the
result, providing a simple, but accurate look up table to estimate the redshift
of distant red galaxies.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:36:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kurtz",
"Michael J.",
""
],
[
"Geller",
"Margaret J.",
""
],
[
"Fabricant",
"Daniel G.",
""
],
[
"Wyatt",
"William F.",
""
],
[
"Dell'Antonio",
"Ian P.",
""
]
] |
0707.0485 | GianLuca Israel | G.L. Israel (1), D. Gotz (2), S. Zane (3), S. Dall'osso (1), N. Rea
(4) and L. Stella (1) ((1) Inaf Oa Roma, (2) Cea Saclay, (3) MSSL, (4) Sron) | Linking the X-ray timing and spectral properties of the glitching AXP
1RXS J170849-400910 | Submitted to A&A, 4 pages; results presented at the INT meeting "The
Neutron Star Crust and Surface: Observations and Models" on June 27; referee
comments added | null | 10.1051/0004-6361:20078215 | null | astro-ph | null | Previous studies of the X-ray flux and spectral properties of 1RXS
J170849-400910 showed hints of a possible correlation with the spin glitches
that occurred in 1999 and 2001. However, due to the sparseness of spectral
measurements and the paucity of detected glitches no firm conclusion could be
drawn. We retrieved and analysed archival XTE pointings of 1RXS J170849-400910
covering the time interval between January 2003 and June 2006 and carried out a
detailed timing analysis by means of phase fitting techniques. We detected two
relatively large glitches Delta nu / nu of 1.2 and 2.1 10^-6 occurred in
January and June 2005. Interestingly, the occurrence times of these glitches
are in agreement with the predictions made in our previous studies. This
finding strongly suggests a connection between the flux, spectral and timing
properties of 1RXS J170849-400910.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:41:52 GMT"
},
{
"version": "v2",
"created": "Tue, 3 Jul 2007 21:48:10 GMT"
},
{
"version": "v3",
"created": "Thu, 29 Nov 2007 21:32:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Israel",
"G. L.",
"",
"Inaf Oa Roma"
],
[
"Gotz",
"D.",
"",
"Cea Saclay"
],
[
"Zane",
"S.",
"",
"MSSL"
],
[
"Dall'osso",
"S.",
"",
"Inaf Oa Roma"
],
[
"Rea",
"N.",
"",
"Sron"
],
[
"Stella",
"L.",
"",
"Inaf Oa Roma"
]
] |
0707.0486 | Matthew Lister | Matthew L. Lister | Blazar Demographics with MOJAVE and GLAST | 2 pages; to appear in Proc. of First GLAST Symposium (Stanford, Feb.
5-8, 2007), eds. S.Ritz, P.F. Michelson, and C.Meegan, AIP Conf. Series | AIPConf.Proc.921:345-346,2007 | 10.1063/1.2757344 | null | astro-ph | null | MOJAVE is a long term VLBA program to investigate the kinematics and
polarization evolution of a complete sample of 133 active galactic nuclei
selected on the basis of compact, relativistically beamed jet emission at 15
GHz. By fitting to the apparent distributions of superluminal speed and jet
luminosity, we can constrain the Lorentz factor distribution and intrinsic
luminosity function of the radio-selected blazar parent population. These
low-energy peaked blazars formed a significant fraction of all EGRET
detections, and should figure prominently in the GLAST source catalog. Using
simple models, we investigate the predicted distribution of GLAST blazars in
the gamma-ray/radio flux density plane, and describe an extension of the MOJAVE
survey that will provide extensive parsec-scale jet information in complete
regions of this plane. We find that if a population of intrinsically radio
bright yet gamma-ray weak blazars exists, its signal will be largely wiped out
by the large gamma-ray flux scatter associated with Doppler beaming.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:35:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lister",
"Matthew L.",
""
]
] |
0707.0487 | Krishnendu Gongopadhyay | Krishnendu Gongopadhyay, Ravi S. Kulkarni | $z$-Classes of Isometries of The Hyperbolic Space | accepted by Conform. Geom. Dyn | Conform. Geom. Dyn. 13 (2009), 91--109. | null | null | math.GT math.GR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let $G$ be a group. Two elements $x, y$ are said to be {\it $z$-equivalent}
if their centralizers are conjugate in $G$. The class equation of $G$ is the
partition of $G$ into conjugacy classes. Further decomposition of conjugacy
classes into $z$-classes provides an important information about the internal
structure of the group.
Let $I(\H^n)$ denote the group of isometries of the hyperbolic $n$-space. We
show that the number of $z$-classes in $I(\H^n)$ is finite. We actually compute
their number, cf. theorem 1.3. We interpret the finiteness of $z$-classes as
accounting for the finiteness of "dynamical types" in $I(\H^n)$. Along the way
we also parametrize conjugacy classes. We mainly use the linear model for the
hyperbolic space for this purpose. This description of parametrizing conjugacy
classes appears to be new.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:50:25 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Aug 2008 13:53:50 GMT"
},
{
"version": "v3",
"created": "Wed, 4 Mar 2009 17:40:43 GMT"
}
] | 2010-02-05T00:00:00 | [
[
"Gongopadhyay",
"Krishnendu",
""
],
[
"Kulkarni",
"Ravi S.",
""
]
] |
0707.0488 | Chung-Lin Shan | Chung-Lin Shan | Theoretical Interpretation of Experimental Data from Direct Dark Matter
Detection | Ph.D. Thesis, Advisor: Manuel Drees, 146 pages, 34 figures. Part of
this work has been published in JCAP 0706, 011 (2007) | null | null | null | astro-ph hep-ph | null | Weakly Interacting Massive Particles (WIMPs) are one of the leading
candidates for Dark Matter. Currently, the most promising method to detect
WIMPs is the direct detection of the recoil energy deposited in a
low-background laboratory detector due to elastic WIMP-nucleus scattering. So
far the usual procedure has been to predict the event rate of direct detection
of WIMPs based on some model(s) of the Galactic halo from cosmology and of
WIMPs from elementary particle physics. The aim of this work is to invert this
process. In this thesis I present methods which allow to reconstruct (the
moments of) the WIMP velocity distribution function as well as to determine the
WIMP mass from the recoil energy spectrum as well as from experimental data
directly. The reconstruction of the velocity distribution function has been
further extended to take into account the annual modulation of the event rate.
Moreover, the reconstruction of the amplitude of the annual modulation of the
velocity distribution and an alternative, better way for confirming the annual
modulation of the event rate have been discussed. On the other hand, the
determination of the WIMP mass by combining two (or more) experiments with
different detector materials has been developed. All formulae and expressions
given here are not only independent of the model of Galactic halo but also of
that of WIMPs. This means that we need neither the as yet unknown WIMP density
near the Earth nor the WIMP-nucleus cross section. The only information which
we need is the measured recoil energies and their measuring times.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 19:57:20 GMT"
},
{
"version": "v2",
"created": "Tue, 3 Jul 2007 21:28:07 GMT"
},
{
"version": "v3",
"created": "Fri, 19 Oct 2007 09:13:11 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Shan",
"Chung-Lin",
""
]
] |
0707.0489 | Brenda Matthews | B.C. Matthews, J.S. Greaves, W.S. Holland, M.C. Wyatt, M.J. Barlow, P.
Bastien, C.A. Beichman, A. Biggs, H.M. Butner, W.R.F. Dent, J. Di Francesco,
C. Dominik, L. Fissel, P. Friberg, A.G. Gibb, M. Halpern, R.J. Ivison, R.
Jayawardhana, T. Jenness, D. Johnstone, JJ Kavelaars, J.L. Marshall, N.
Phillips, G. Schieven, I.A.G. Snellen, H.J. Walker, D. Ward-Thompson, B.
Weferling, G.J. White, J. Yates, M. Zhu | An Unbiased Survey of 500 Nearby Stars for Debris Disks: A JCMT Legacy
Program | 11 pages, 7 figures (3 color), accepted by the Publications of the
Astronomical Society of the Pacific | null | 10.1086/521318 | null | astro-ph | null | We present the scientific motivation and observing plan for an upcoming
detection survey for debris disks using the James Clerk Maxwell Telescope. The
SCUBA-2 Unbiased Nearby Stars (SUNS) Survey will observe 500 nearby main
sequence and sub-giant stars (100 of each of the A, F, G, K and M spectral
classes) to the 850 micron extragalactic confusion limit to search for evidence
of submillimeter excess, an indication of circumstellar material. The survey
distance boundaries are 8.6, 16.5, 22, 25 and 45 pc for M, K, G, F and A stars,
respectively, and all targets lie between the declinations of -40 deg to 80
deg. In this survey, no star will be rejected based on its inherent properties:
binarity, presence of planetary companions, spectral type or age. This will be
the first unbiased survey for debris disks since IRAS. We expect to detect ~125
debris disks, including ~50 cold disks not detectable in current shorter
wavelength surveys. A substantial amount of complementary data will be required
to constrain the temperatures and masses of discovered disks. High resolution
studies will likely be required to resolve many of the disks. Therefore, these
systems will be the focus of future observational studies using a variety of
observatories to characterize their physical properties. For non-detected
systems, this survey will set constraints (upper limits) on the amount of
circumstellar dust, of typically 200 times the Kuiper Belt mass, but as low as
10 times the Kuiper Belt mass for the nearest stars in the sample
(approximately 2 pc).
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:00:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Matthews",
"B. C.",
""
],
[
"Greaves",
"J. S.",
""
],
[
"Holland",
"W. S.",
""
],
[
"Wyatt",
"M. C.",
""
],
[
"Barlow",
"M. J.",
""
],
[
"Bastien",
"P.",
""
],
[
"Beichman",
"C. A.",
""
],
[
"Biggs",
"A.",
""
],
[
"Butner",
"H. M.",
""
],
[
"Dent",
"W. R. F.",
""
],
[
"Di Francesco",
"J.",
""
],
[
"Dominik",
"C.",
""
],
[
"Fissel",
"L.",
""
],
[
"Friberg",
"P.",
""
],
[
"Gibb",
"A. G.",
""
],
[
"Halpern",
"M.",
""
],
[
"Ivison",
"R. J.",
""
],
[
"Jayawardhana",
"R.",
""
],
[
"Jenness",
"T.",
""
],
[
"Johnstone",
"D.",
""
],
[
"Kavelaars",
"JJ",
""
],
[
"Marshall",
"J. L.",
""
],
[
"Phillips",
"N.",
""
],
[
"Schieven",
"G.",
""
],
[
"Snellen",
"I. A. G.",
""
],
[
"Walker",
"H. J.",
""
],
[
"Ward-Thompson",
"D.",
""
],
[
"Weferling",
"B.",
""
],
[
"White",
"G. J.",
""
],
[
"Yates",
"J.",
""
],
[
"Zhu",
"M.",
""
]
] |
0707.0490 | Sara L. Ellison | Sara L. Ellison, Jason X. Prochaska, Sebastian Lopez | The Galactic Deuterium Abundance and Dust Depletion: Insights From an
Expanded Ti/H Sample | Accepted for publication in MNRAS, 11 pages | null | 10.1111/j.1365-2966.2007.12192.x | null | astro-ph | null | The primordial abundance of deuterium (D/H) yields a measure of the density
of baryons in the universe and is an important complement to determinations
from cosmic microwave background (CMB) experiments. Indeed, the current small
sample of high redshift D/H measurements from quasar absorption line studies
are in excellent agreement with CMB-derived values. Conversely, absorption line
measurements of the Galactic D/H ratio in almost 50 stellar sightlines show a
puzzlingly large scatter outside the Local Bubble which is difficult to explain
simply by astration from the primordial value. Here, we investigate the dust
depletion scenario by studying the correlation between D/H and the abundance of
titanium, one of the most refractory elements readily observed in the ISM. With
a sample 3 times larger than previous work, we confirm a correlation between
Ti/H and D/H at the 97% confidence level. However, the magnitude of this
dependence is difficult to reconcile with a simple model of dust depletion for
two reasons. First, contrary to what is expected from local depletion rates,
the gradient of the highly refractory Ti is much shallower than that observed
for Fe and Si. Second, we do not observe the established tight, steep
correlation between [Ti/H] and the mean volume density of hydrogen. Therefore,
whilst dust remains a plausible explanation for the local D/H variations, the
abundances of at least some of the refractory elements do not provide unanimous
support for this scenario. We also argue that the correlations of [Si/H],
[Fe/H], and [Ti/H] with D/H are inconsistent with a simple infall model of low
metallicity gas with approximately solar abundances as the dominant cause for D
variations.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:08:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ellison",
"Sara L.",
""
],
[
"Prochaska",
"Jason X.",
""
],
[
"Lopez",
"Sebastian",
""
]
] |
0707.0491 | Anatoly Vershik | Anatoly Vershik | L.V.Kantorovich and Linear Programming | 28 p | null | null | null | math.HO math.OC | null | I want to write about what I know and remember about the activities of Leonid
Vital'evich Kantorovich, an outstanding scientist of the 20th century; about
his dramatic struggle for recognition of his mathematical economic theories;
about the initial stage of the history of linear programming; about beautuful
Kantorovich metric, about the creation of a new area of mathematical activity
related to economic applications, which is called sometimes operation research,
sometimes mathematical economics, sometimes linear and convex programming, or
economic cybernetics, etc.; about its place in the modern mathematical
landscape; and, finally, about several personal impressions of this
distinguished scientist. The notes in no way pretend to exhaust these topics.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 18:58:53 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Vershik",
"Anatoly",
""
]
] |
0707.0492 | Lutz Haberzettl | L. Haberzettl, D.J. Bomans, R.-J. Dettmar | Low Surface Brightness Galaxies around the HDF-S: II. Distances and
volume densities | 12 pages, 20 figures, accepted by A&A | null | 10.1051/0004-6361:20066918 | null | astro-ph | null | With this study we aim at the spectroscopic verification of a photometrically
selected sample of Low Surface Brightness (LSB) galaxy candidates in a field
around the Hubble Deep Field-South (HDF-S). The sample helps to extend the
parameter space for LSB galaxies to lower central surface brightnesses and to
provide better estimates on the volume densities of these objects. To derive
redshifts for the LSB candidates, long-slit spectra were obtained covering a
spectral range from 3400{\AA} to 7500{\AA}. The observations have been obtained
using the ESO 3.6m telescope, equipped with the EFOSC2 spectrograph. From the
measured radial velocities, distances could be estimated. With this distance
information, it is possible to differentiate between true LSB galaxies and
higher redshift High Surface Brightness (HSB) galaxies which may contaminate
the sample. A correction for the surface brightnesses can then be applied,
accounting for the cosmological dimming effect (``Tolman Dimming''). We show
that ~70% of the LSB candidates, selected based on their location in the
color-color space, are real LSB galaxies. Their position in the color-color
diagrams, therefore, indicate that the LSB galaxies have a different stellar
population mix resulting from a different star formation history compared to
HSBs. Our LSB galaxy sample consists only of large disk galaxies with
scale-length between 2.5kpc and 7.3kpc. We confirm the flat central surface
brightness distribution of previous surveys and extend this distribution down
to central surface brightnesses of 27 B mag arcsec^-2.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:21:52 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Haberzettl",
"L.",
""
],
[
"Bomans",
"D. J.",
""
],
[
"Dettmar",
"R. -J.",
""
]
] |
0707.0493 | Andrew Charman | A. E. Charman, R. R. Lindberg | A comment on `Wave-breaking Limits for relativistic electrostatic waves
in a one-dimensional warm plasma' Phys. Plasmas 13 123102 by R. M. G. M.
Trines and P. A. Norreys | 8 pages | null | null | null | physics.plasm-ph | null | Trines and Norreys state that a principle aim of their work on warm
wave-breaking was ``to create some order in the diverse landscape of warm fluid
models and establish which model is most suitable for the study of wave
breaking in thermal plasma.'' Unfortunately, we must conclude that they have
obfuscated more than they have clarified, and have advanced the waterbag model
only by exaggerating or misstating its benefits while mischaracterizing
features of alternative warm fluid theories.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:21:54 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Charman",
"A. E.",
""
],
[
"Lindberg",
"R. R.",
""
]
] |
0707.0494 | He Jingsong | Jingsong He, Kelei Tian, Angela Foerster, Wen-xiu Ma | Additional Symmetry of CKP hierarchy | 13pages, LaTex, to appear in Lett.Math.Phys | null | null | null | nlin.SI | null | Based on the Orlov and Shulman's M operator, the additional symmetries and
the string equation of the CKP hierarchy are established, and then the higher
order constraints on $L^l$ are obtained. In addition, the generating function
and some properties are also given. In particular, the additional symmetry
flows form a new infinite dimensional algebra $W^C_{1+\infty}$, which is a
subalgebra of $W_{1+\infty}$.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:23:56 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"He",
"Jingsong",
""
],
[
"Tian",
"Kelei",
""
],
[
"Foerster",
"Angela",
""
],
[
"Ma",
"Wen-xiu",
""
]
] |
0707.0495 | Jonas Fransson | J. Fransson, J. -X. Zhu, A. V. Balatsky | Vibrating Superconducting Island in a Josephson Junction | 4 pages, 3 figures, to appear in Phys. Rev. Lett | Phys. Rev. Lett. 101, 067202 (2008) | 10.1103/PhysRevLett.101.067202 | null | cond-mat.mes-hall | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a combined nanomechanical-supercondcuting device that allows the
Cooper pair tunneling to interfere with the mechanical motion of the middle
superconducting island. Coupling of mechanical oscillations of a
superconducting island between two superconducting leads to the electronic
tunneling generate a supercurrent which is modulated by the oscillatory motion
of the island. This coupling produces alternating finite and vanishing
supercurrent as function of the superconducting phases. Current peaks are
sensitive to the superconducting phase shifts relative to each other. The
proposed device may be used to study the nanoelectromechanical coupling in case
of superconducting electronics.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:23:59 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jul 2008 15:01:25 GMT"
}
] | 2008-08-06T00:00:00 | [
[
"Fransson",
"J.",
""
],
[
"Zhu",
"J. -X.",
""
],
[
"Balatsky",
"A. V.",
""
]
] |
0707.0496 | Jae-Seung Lee | Jae-Seung Lee, Mary A. Rohrdanz, and A. K. Khitrin | Controlled spontaneous emission | 25 pages including 11 figures | null | 10.1088/0953-4075/41/4/045504 | null | quant-ph | null | The problem of spontaneous emission is studied by a direct computer
simulation of the dynamics of a combined system: atom + radiation field. The
parameters of the discrete finite model, including up to 20k field oscillators,
have been optimized by a comparison with the exact solution for the case when
the oscillators have equidistant frequencies and equal coupling constants.
Simulation of the effect of multi-pulse sequence of phase kicks and emission by
a pair of atoms shows that both the frequency and the linewidth of the emitted
spectrum could be controlled.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:35:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lee",
"Jae-Seung",
""
],
[
"Rohrdanz",
"Mary A.",
""
],
[
"Khitrin",
"A. K.",
""
]
] |
0707.0497 | Alexander Westphal | Marco Serone and Alexander Westphal | Moduli Stabilization in Meta-Stable Heterotic Supergravity Vacua | 1+31 pages, LaTeX, uses JHEP3 class, v2: references corrected and
added, version published in JHEP | JHEP0708:080,2007 | 10.1088/1126-6708/2007/08/080 | SISSA-38/2007/EP | hep-th hep-ph | null | We revisit the issue of moduli stabilization in a class of N=1 four
dimensional supergravity theories which are low energy descriptions of standard
perturbative heterotic string vacua compactified on Calabi-Yau spaces. In
particular, we show how it is possible to stabilize the universal dilaton and
Kahler moduli in a de Sitter/Minkowski vacuum with low energy supersymmetry
breaking by means of non-perturbative gauge dynamics, including recent results
by Intriligator, Seiberg and Shih. The non-SUSY vacua are meta-stable but
sufficiently long-lived.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:51:44 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 10:09:22 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Serone",
"Marco",
""
],
[
"Westphal",
"Alexander",
""
]
] |
0707.0498 | Roy Murphy Dr | Roy E. Murphy | The Role of Time in the Creation of Knowledge | Adaptive Processes | null | null | null | cs.LG cs.AI cs.IT math.IT | null | This paper I assume that in humans the creation of knowledge depends on a
discrete time, or stage, sequential decision-making process subjected to a
stochastic, information transmitting environment. For each time-stage, this
environment randomly transmits Shannon type information-packets to the
decision-maker, who examines each of them for relevancy and then determines his
optimal choices. Using this set of relevant information-packets, the
decision-maker adapts, over time, to the stochastic nature of his environment,
and optimizes the subjective expected rate-of-growth of knowledge. The
decision-maker's optimal actions, lead to a decision function that involves,
over time, his view of the subjective entropy of the environmental process and
other important parameters at each time-stage of the process. Using this model
of human behavior, one could create psychometric experiments using computer
simulation and real decision-makers, to play programmed games to measure the
resulting human performance.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:43:43 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Murphy",
"Roy E.",
""
]
] |
0707.0499 | Syksy Rasanen | Francesc Ferrer, Syksy Rasanen | Lovelock inflation and the number of large dimensions | 16 pages, 1 figure. v2: published version, added clarifications | JHEP 0711:003,2007 | 10.1088/1126-6708/2007/11/003 | CERN-PH-TH/2007-113 | hep-th astro-ph gr-qc hep-ph | null | We discuss an inflationary scenario based on Lovelock terms. These higher
order curvature terms can lead to inflation when there are more than three
spatial dimensions. Inflation will end if the extra dimensions are stabilised,
so that at most three dimensions are free to expand. This relates graceful exit
to the number of large dimensions.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 17:01:53 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Nov 2007 13:42:28 GMT"
}
] | 2010-02-03T00:00:00 | [
[
"Ferrer",
"Francesc",
""
],
[
"Rasanen",
"Syksy",
""
]
] |
0707.0500 | Wenjun Li Ms. | Wenjun Li, Yanbing Zhang and Huaiyu Dai | Location-Aided Fast Distributed Consensus in Wireless Networks | 44 pages, 14 figures. Submitted to IEEE Transactions on Information
Theory | null | 10.1109/TIT.2010.2081030 | null | cs.IT math.IT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Existing works on distributed consensus explore linear iterations based on
reversible Markov chains, which contribute to the slow convergence of the
algorithms. It has been observed that by overcoming the diffusive behavior of
reversible chains, certain nonreversible chains lifted from reversible ones mix
substantially faster than the original chains. In this paper, we investigate
the idea of accelerating distributed consensus via lifting Markov chains, and
propose a class of Location-Aided Distributed Averaging (LADA) algorithms for
wireless networks, where nodes' coarse location information is used to
construct nonreversible chains that facilitate distributed computing and
cooperative processing. First, two general pseudo-algorithms are presented to
illustrate the notion of distributed averaging through chain-lifting. These
pseudo-algorithms are then respectively instantiated through one LADA algorithm
on grid networks, and one on general wireless networks. For a $k\times k$ grid
network, the proposed LADA algorithm achieves an $\epsilon$-averaging time of
$O(k\log(\epsilon^{-1}))$. Based on this algorithm, in a wireless network with
transmission range $r$, an $\epsilon$-averaging time of
$O(r^{-1}\log(\epsilon^{-1}))$ can be attained through a centralized algorithm.
Subsequently, we present a fully-distributed LADA algorithm for wireless
networks, which utilizes only the direction information of neighbors to
construct nonreversible chains. It is shown that this distributed LADA
algorithm achieves the same scaling law in averaging time as the centralized
scheme. Finally, we propose a cluster-based LADA (C-LADA) algorithm, which,
requiring no central coordination, provides the additional benefit of reduced
message complexity compared with the distributed LADA algorithm.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:47:08 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Jul 2008 23:54:00 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Mar 2009 23:40:57 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Li",
"Wenjun",
""
],
[
"Zhang",
"Yanbing",
""
],
[
"Dai",
"Huaiyu",
""
]
] |
0707.0501 | Claus Tappert | C. Tappert, B. T. Gaensicke, L. Schmidtobreick, R. E. Mennickent, F.
P. Navarrete | K-band spectroscopy of pre-cataclysmic variables | 10 pages, 5 figures, A&A, accepted | null | 10.1051/0004-6361:20077679 | null | astro-ph | null | We have taken K-band spectroscopy of a sample of 13 pre-CVs in order to
examine them for anomalous chemical abundances. In particular, we study the
strength of the 12CO and 13CO absorption bands that have been found diminished
and enhanced, respectively, in similar studies of CVs.
All our systems show CO abundances that are within the range observed for
single stars. The weakest 12CO bands with respect to the spectral type are
found in the pre-CV BPM 71214, although on a much smaller scale than observed
in CVs. Furthermore there is no evidence for enhanced 13CO. Taking into account
that our sample is subject to the present observational bias that favours the
discovery of young pre-CVs with secondary stars of late spectral types, we can
conclude the following: 1) our study provides observational proof that the CO
anomalies discovered in certain CVs are not due to any material acquired during
the common envelope phase, and 2) if the CO anomalies in certain CVs are not
due to accretion of processed material during nova outburst, then the
progenitors of these CVs are of a significantly different type than the
currently known sample of pre-CVs.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:51:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tappert",
"C.",
""
],
[
"Gaensicke",
"B. T.",
""
],
[
"Schmidtobreick",
"L.",
""
],
[
"Mennickent",
"R. E.",
""
],
[
"Navarrete",
"F. P.",
""
]
] |
0707.0502 | Walter Wilcox | Dean Darnell, Ronald B. Morgan, and Walter Wilcox | Deflated GMRES for Systems with Multiple Shifts and Multiple Right-Hand
Sides | 19 pages, 9 figures | LinearAlgebraAppl.429:2415-2434,2008 | 10.1016/j.laa.2008.04.019 | BU-HEPP-07-05 | math-ph hep-lat math.MP | null | We consider solution of multiply shifted systems of nonsymmetric linear
equations, possibly also with multiple right-hand sides. First, for a single
right-hand side, the matrix is shifted by several multiples of the identity.
Such problems arise in a number of applications, including lattice quantum
chromodynamics where the matrices are complex and non-Hermitian. Some Krylov
iterative methods such as GMRES and BiCGStab have been used to solve multiply
shifted systems for about the cost of solving just one system. Restarted GMRES
can be improved by deflating eigenvalues for matrices that have a few small
eigenvalues. We show that a particular deflated method, GMRES-DR, can be
applied to multiply shifted systems. In quantum chromodynamics, it is common to
have multiple right-hand sides with multiple shifts for each right-hand side.
We develop a method that efficiently solves the multiple right-hand sides by
using a deflated version of GMRES and yet keeps costs for all of the multiply
shifted systems close to those for one shift. An example is given showing this
can be extremely effective with a quantum chromodynamics matrix.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 20:55:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Darnell",
"Dean",
""
],
[
"Morgan",
"Ronald B.",
""
],
[
"Wilcox",
"Walter",
""
]
] |
0707.0503 | Joshua N. Winn | Joshua N. Winn, John Asher Johnson, Kathryn M. G. Peek, Geoffrey W.
Marcy, Gaspar A. Bakos, Keigo Enya, Norio Narita, Yasushi Suto, Edwin L.
Turner, Steven S. Vogt | Spin-Orbit Alignment for the Eccentric Exoplanet HD 147506b | To appear in ApJ Letters (12 pages, 1 figure) | null | 10.1086/521362 | null | astro-ph | null | The short-period exoplanet HD 147506b (also known as HAT-P-2b) has an
eccentric orbit, raising the possibility that it migrated through planet-planet
scattering or Kozai oscillations accompanied by tidal dissipation. Either of
these scenarios could have significantly tilted the orbit relative to the host
star's equatorial plane. Here we present spectroscopy of a transit of HD
147506b, and assess the spin-orbit alignment via the Rossiter-McLaughlin
effect. We find the sky projections of the stellar spin axis and orbital axis
to be aligned within 14 deg. Thus we find no corroborating evidence for
scattering or Kozai migration, although these scenarios cannot be ruled out
with the present data.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 22:43:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Winn",
"Joshua N.",
""
],
[
"Johnson",
"John Asher",
""
],
[
"Peek",
"Kathryn M. G.",
""
],
[
"Marcy",
"Geoffrey W.",
""
],
[
"Bakos",
"Gaspar A.",
""
],
[
"Enya",
"Keigo",
""
],
[
"Narita",
"Norio",
""
],
[
"Suto",
"Yasushi",
""
],
[
"Turner",
"Edwin L.",
""
],
[
"Vogt",
"Steven S.",
""
]
] |
0707.0504 | Ching-Hwa Kiang | Nolan C. Harris, Yang Song, and Ching-Hwa Kiang | Experimental Free Energy Surface Reconstruction From Single-Molecule
Force Spectroscopy Using Jarzynski's Equality | 4 pages, 3 figures. Phys. Rev. Lett. (2007) accepted | null | 10.1103/PhysRevLett.99.068101 | null | physics.bio-ph physics.gen-ph | null | We used the atomic force microscope to manipulate and unfold individual
molecules of the titin I27 domain and reconstructed its free energy surface
using Jarzynski's equality. The free energy surface for both stretching and
unfolding was reconstructed using an exact formula that relates the
nonequilibrium work fluctuations to the molecular free energy. In addition, the
unfolding free energy barrier, i.e. the activation energy, was directly
obtained from experimental data for the first time. This work demonstrates that
Jarzynski's equality can be used to analyze nonequilibrium single-molecule
experiments, and to obtain the free energy surfaces for molecular systems,
including interactions for which only nonequilibrium work can be measured.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:04:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Harris",
"Nolan C.",
""
],
[
"Song",
"Yang",
""
],
[
"Kiang",
"Ching-Hwa",
""
]
] |
0707.0505 | Walter Wilcox | Ronald B. Morgan and Walter Wilcox | Deflated Iterative Methods for Linear Equations with Multiple Right-Hand
Sides | 13 pages, 5 figures | null | null | BU-HEPP-07-06 | math-ph hep-lat math.MP | null | A new approach is discussed for solving large nonsymmetric systems of linear
equations with multiple right-hand sides. The first system is solved with a
deflated GMRES method that generates eigenvector information at the same time
that the linear equations are solved. Subsequent systems are solved by
combining restarted GMRES with a projection over the previously determined
eigenvectors. This approach offers an alternative to block methods, and it can
also be combined with a block method. It is useful when there are a limited
number of small eigenvalues that slow the convergence. An example is given
showing significant improvement for a problem from quantum chromodynamics. The
second and subsequent right-hand sides are solved much quicker than without the
deflation. This new approach is relatively simple to implement and is very
efficient compared to other deflation methods.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:13:14 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Morgan",
"Ronald B.",
""
],
[
"Wilcox",
"Walter",
""
]
] |
0707.0506 | Katherine Blundell | Felix J. Lockman, Katherine M. Blundell, W. M. Goss | The Distance to SS433/W50 and its Interaction with the ISM | accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12170.x | null | astro-ph | null | [ABRIDGED] The distance to the relativistic jet source SS433 and the related
supernova remnant W50 is re-examined using new observations of HI in absorption
from the VLA, HI in emission from the GBT, and 12CO emission from the FCRAO.
The new measurements show HI in absorption against SS433 to a velocity of 75
km/s but not to the velocity of the tangent point, which bounds the kinematic
distance at 5.5 < d_k < 6.5 kpc. This is entirely consistent with a 5.5 +/- 0.2
kpc distance determined from light travel-time arguments (Blundell & Bowler
2004). The HI emission map shows evidence of interaction of the lobes of W50
with the interstellar medium near the adopted systemic velocity of V_LSR = 75
km/s. The western lobe sits in a cavity in the HI emission near the Galactic
plane, while the eastern lobe terminates at an expanding HI shell. The
expanding shell has a radius of 40 pc, contains 8 +/- 3 x 10^3 M_sun of HI and
has a measured kinetic energy of 3 +/- 1.5 x 10^{49} ergs. There may also be a
static HI ring or shell around the main part of W50 itself at an LSR velocity
of 75 km/s, with a radius of 70 pc and a mass in HI of 3.5 - 10 x 10^4 M_sun.
We do not find convincing evidence for the interaction of the system with any
molecular cloud or with HI at other velocities. The HI emission data suggest
that SS433 lies in an interstellar environment substantially denser than
average for its distance from the Galactic plane. This Population I system, now
about 200 pc below the Galactic plane, most likely originated as a runaway
O-star binary ejected from a young cluster in the plane. New astrometric data
on SS433 show that the system now has a peculiar velocity of a few tens of km/s
in the direction of the Galactic plane. From this peculiar velocity and the
symmetry of the W50 remnant we derive a time since the SN of < 10^5 yr.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 13:37:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lockman",
"Felix J.",
""
],
[
"Blundell",
"Katherine M.",
""
],
[
"Goss",
"W. M.",
""
]
] |
0707.0507 | Feng Ye | F. Ye, B. Lorenz, Q. Huang, Y. Q. Wang, Y. Y. Sun, C. W. Chu, J. A.
Fernandez-Baca, Pengcheng Dai, H. A. Mook | Incommensurate magnetic structure in the orthorhombic perovskite ErMnO_3 | 4 pages, 3 figures | Phys. Rev. B 76, 060402(R) (2007) | 10.1103/PhysRevB.76.060402 | null | cond-mat.str-el | null | By combining dielectric, specific heat, and magnetization measurements and
high-resolution neutron powder diffraction, we have investigated the
thermodynamic and magnetic/structural properties of the metastable orthorhombic
perovskite ErMnO_3 prepared by high-pressure synthesis. The system becomes
antiferromagnetically correlated below 42 K and undergoes a lock-in transition
at 28 K with propagation wave vector (0,k_b,0), which remains incommensurate at
low temperature. The intercorrelation between the magnetic structure and
electric properties and the role of the rare earth moment are discussed.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:31:58 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 18:48:21 GMT"
}
] | 2007-08-02T00:00:00 | [
[
"Ye",
"F.",
""
],
[
"Lorenz",
"B.",
""
],
[
"Huang",
"Q.",
""
],
[
"Wang",
"Y. Q.",
""
],
[
"Sun",
"Y. Y.",
""
],
[
"Chu",
"C. W.",
""
],
[
"Fernandez-Baca",
"J. A.",
""
],
[
"Dai",
"Pengcheng",
""
],
[
"Mook",
"H. A.",
""
]
] |
0707.0508 | Justin Finke | Justin Finke and Markus Boettcher | X-ray Spectral Signatures of the Photon Bubble Model for Ultraluminous
X-ray Sources | Accepted for publication in the Astrophysical Journal | Astrophys.J.667:395-403,2007 | 10.1086/520946 | null | astro-ph | null | The nature of ultraluminous X-ray sources in nearby galaxies is one of the
major open questions in modern X-ray astrophysics. One possible explanation for
these objects is an inhomogeneous, radiation dominated accretion disk around a
$\sim 10 M_{\odot}$ black hole -- the so-called ``photon bubble'' model. While
previous studies of this model have focused primarily on its
radiation-hydrodynamics aspects, in this paper, we provide an analysis of its
X-ray spectral (continuum and possible edge and line) characteristics. Compton
reflection between high and low density regions in the disk may provide the key
to distinguishing this model from others, such as accretion onto an
intermediate mass black hole. We couple a Monte Carlo/Fokker-Planck radiation
transport code with the XSTAR code for reflection to simulate the photon
spectra produced in a photon bubble model for ULXs. We find that reflection
components tend to be very weak and in most cases not observable, and make
predictions for the shape of the high-energy Comptonizing spectra. In many
cases the Comptonization dominates the spectra even down to $\sim$ a few keV.
In one simulation, a $\sim 9 \kev$ feature was found, which may be considered a
signature of photon bubbles in ULXs; furthermore, we make predictions of high
energy power-laws which may be observed by future instruments.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:38:07 GMT"
}
] | 2011-02-11T00:00:00 | [
[
"Finke",
"Justin",
""
],
[
"Boettcher",
"Markus",
""
]
] |
0707.0509 | Min-Chul Cha | Min-Chul Cha, Gerardo Ortiz | Order-Parameter Correlation Functions in Quantum Critical Phenomena | 4 pages, 4 figures | null | null | null | cond-mat.stat-mech cond-mat.str-el | null | We investigate the functional form of the order-parameter (two-point)
correlation function in quantum critical phenomena. Contrary to the common
lore, when there is no particle-hole symmetry we find that the equal-time
correlation function at criticality does not display a diverging correlation
length. We illustrate our conclusions by Monte Carlo calculations of the
quantum rotor model in $d=2$ space dimensions
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:38:34 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Cha",
"Min-Chul",
""
],
[
"Ortiz",
"Gerardo",
""
]
] |
0707.0510 | Sunil Ahuja | S. Ahuja, V. Yakhot, I. G. Kevrekidis | Computational coarse graining of a randomly forced 1-D Burgers equation | 21 pages, 7 figures | null | 10.1063/1.2856212 | null | physics.comp-ph | null | We explore a computational approach to coarse graining the evolution of the
large-scale features of a randomly forced Burgers equation in one spatial
dimension. The long term evolution of the solution energy spectrum appears
self-similar in time. We demonstrate coarse projective integration and coarse
dynamic renormalization as tools that accelerate the extraction of macroscopic
information (integration in time, self-similar shapes, and nontrivial dynamic
exponents) from short bursts of appropriately initialized direct simulation.
These procedures solve numerically an effective evolution equation for the
energy spectrum without ever deriving this equation in closed form.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 21:42:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ahuja",
"S.",
""
],
[
"Yakhot",
"V.",
""
],
[
"Kevrekidis",
"I. G.",
""
]
] |
0707.0511 | A. Melikyan | Ashok Das, A. Melikyan, V.O. Rivelles | The S-matrix of the Faddeev-Reshetikhin Model, Diagonalizability and PT
Symmetry | 32 pages, 1 figure; references added, version published in JHEP | JHEP0709:104,2007 | 10.1088/1126-6708/2007/09/104 | null | hep-th | null | We study the question of diagonalizability of the Hamiltonian for the
Faddeev-Reshetikhin (FR) model in the two particle sector. Although the two
particle S-matrix element for the FR model, which may be relevant for the
quantization of strings on $AdS_{5}\times S^{5}$, has been calculated recently
using field theoretic methods, we find that the Hamiltonian for the system in
this sector is not diagonalizable. We trace the difficulty to the fact that the
interaction term in the Hamiltonian violating Lorentz invariance leads to
discontinuity conditions (matching conditions) that cannot be satisfied. We
determine the most general quartic interaction Hamiltonian that can be
diagonalized. This includes the bosonic Thirring model as well as the bosonic
chiral Gross-Neveu model which we find share the same S-matrix. We explain this
by showing, through a Fierz transformation, that these two models are in fact
equivalent. In addition, we find a general quartic interaction Hamiltonian,
violating Lorentz invariance, that can be diagonalized with the same two
particle S-matrix element as calculated by Klose and Zarembo for the FR model.
This family of generalized interaction Hamiltonians is not Hermitian, but is
$PT$ symmetric. We show that the wave functions for this system are also $PT$
symmetric. Thus, the theory is in a $PT$ unbroken phase which guarantees the
reality of the energy spectrum as well as the unitarity of the S-matrix.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 22:06:58 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 15:33:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Das",
"Ashok",
""
],
[
"Melikyan",
"A.",
""
],
[
"Rivelles",
"V. O.",
""
]
] |
0707.0512 | Ragavachariar Parthasarathy | R.Parthasarathy, K.S.Viswanathan | $(\alpha')^4$ Corrections in Holographic Large N_c QCD and $\pi - \pi$
Scattering | Latex, 13 pages, 1 figure, Text enlarged, two tables introduced, one
more curve is added in the figure, added more references | null | null | null | hep-th hep-ph | null | We calculate the ${\alpha'}^4$ corrections to the non-Abelian DBI action on
the D8-brane in the holographic dual of large N_c QCD proposed by Sakai and
Sugimoto. These give rise to higher derivative terms, in particular, four
derivative contact terms for the pion field with the coupling uniquely
determined. We calculate the pion-pion scattering amplitude near threshold. The
results respecting unitarity are in qualitative agreement with the experimental
curves.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 22:17:44 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 16:36:00 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Parthasarathy",
"R.",
""
],
[
"Viswanathan",
"K. S.",
""
]
] |
0707.0513 | Chazottes | J.-R. Chazottes, J.-M. Gambaudo, E. Ugalde | On the zero-temperature limit of one-dimensional Gibbs measures | This paper has been withdrawn | null | null | null | math.DS math-ph math.MP | null | This paper has been withdrawn by the authors due to an error in the main
theorem.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 22:32:26 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Nov 2007 08:40:58 GMT"
}
] | 2007-11-14T00:00:00 | [
[
"Chazottes",
"J. -R.",
""
],
[
"Gambaudo",
"J. -M.",
""
],
[
"Ugalde",
"E.",
""
]
] |
0707.0514 | Matthew Cargo | Matthew Charles Cargo | Phase space methods and psychoacoustic models in lossy transform coding | null | null | null | null | cs.IT cs.SD math.IT | null | I present a method for lossy transform coding of digital audio that uses the
Weyl symbol calculus for constructing the encoding and decoding transformation.
The method establishes a direct connection between a time-frequency
representation of the signal dependent threshold of masked noise and the
encode/decode pair. The formalism also offers a time-frequency measure of
perceptual entropy.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 22:41:11 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Cargo",
"Matthew Charles",
""
]
] |
0707.0515 | Fabio Iocco | F. Iocco, K. Murase, S. Nagataki and P.D. Serpico | High Energy neutrino signals from the Epoch of Reionization | 9 pages, 5 figures, | Astrophys.J.675:937-945,2008 | 10.1086/526450 | DSF-22/2007; FERMILAB-PUB-07-332-A; SLAC-PUB-12637 | astro-ph | null | We perform a new estimate of the high energy neutrinos expected from GRBs
associated with the first generation of stars in light of new models and
constraints on the epoch of reionization and a more detailed evaluation of the
neutrino emission yields. We also compare the diffuse high energy neutrino
background from Population III stars with the one from "ordinary stars"
(Population II), as estimated consistently within the same cosmological and
astrophysical assumptions. In disagreement with previous literature, we find
that high energy neutrinos from Population III stars will not be observable
with current or near future neutrino telescopes, falling below both IceCube
sensitivity and atmospheric neutrino background under the most extreme
assumptions for the GRB rate. This rules them out as a viable diagnostic tool
for these still elusive metal-free stars.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 23:04:04 GMT"
},
{
"version": "v2",
"created": "Sat, 23 Feb 2008 12:06:22 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Iocco",
"F.",
""
],
[
"Murase",
"K.",
""
],
[
"Nagataki",
"S.",
""
],
[
"Serpico",
"P. D.",
""
]
] |
0707.0516 | Gaspare Lo Curto | G. Lo Curto, R.P. Mignani, R. Perna, and G.L. Israel | Deep VLT infrared observations of X-ray Dim Isolated Neutron Stars | 6 pages, 2 figures, accepted by A&A on 26-06-2007 | null | 10.1051/0004-6361:20077547 | null | astro-ph | null | X-ray observations have unveiled the existence of a family of radio-quiet
Isolated Neutron Stars whose X-ray emission is purely thermal, hence dubbed
X-ray Dim Isolated Neutron Stars (XDINSs). While optical observations have
allowed to relate the thermal emission to the neutron star cooling and to build
the neutron star surface thermal map, IR observations are critical to pinpoint
a spectral turnover produced by a so far unseen magnetospheric component, or by
the presence of a fallback disk. The detection of such a turnover can provide
further evidence of a link between this class of isolated neutron stars and the
magnetars, which show a distinctive spectral flattening in the IR.
Here we present the deepest IR observations ever of five XDINSs, which we use
to constrain a spectral turnover in the IR and the presence of a fallback disk.
The data are obtained using the ISAAC instrument at the VLT.
For none of our targets it was possible to identify the IR counterpart down
to limiting magnitudes H = 21.5 - 22.9. Although these limits are the deepest
ever obtained for neutron stars of this class, they are not deep enough to rule
out the existence and the nature of a possible spectral flattening in the IR.
We also derive, by using disk models, the upper limits on the mass inflow rate
in a fallback disk. We find the existence of a putative fallback disk
consistent (although not confirmed) with our observations.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 00:00:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Curto",
"G. Lo",
""
],
[
"Mignani",
"R. P.",
""
],
[
"Perna",
"R.",
""
],
[
"Israel",
"G. L.",
""
]
] |
0707.0517 | Lester Fox Machado | L. Fox Machado, J.H. Pena, G. Munoz, B. Vargas | On the nature of Delta Scuti star HD 115520 | 10 pages, 6 figures, accepted in Comm. in Asteroseismology | null | 10.1553/cia151s26 | null | astro-ph | null | As a continuation of the study of the newly found Delta Scuti star HD 115520,
we present a period analysis of recently acquired photometric data covering
four nights, as well as some conclusions on the nature of this star.
| [
{
"version": "v1",
"created": "Tue, 3 Jul 2007 23:50:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Machado",
"L. Fox",
""
],
[
"Pena",
"J. H.",
""
],
[
"Munoz",
"G.",
""
],
[
"Vargas",
"B.",
""
]
] |
0707.0518 | Jesse Johnson | Jesse Johnson and Terk Patel | Generalized handlebody sets and non-Haken 3-manifolds | 6 pages | null | null | null | math.GT | null | In the curve complex for a surface, a handlebody set is the set of loops that
bound properly embedded disks in a given handlebody bounded by the surface. A
boundary set is the set of non-separating loops in the curve complex that bound
two-sided, properly embedded surfaces. For a Heegaard splitting, the distance
between the boundary sets of the handlebodies is zero if and only if the
ambient manifold contains a non-separating, two sided incompressible surface.
We show that the boundary set is 2-dense in the curve complex, i.e. every
vertex is within two edges of a point in the boundary set.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 00:17:25 GMT"
}
] | 2007-07-05T00:00:00 | [
[
"Johnson",
"Jesse",
""
],
[
"Patel",
"Terk",
""
]
] |
0707.0519 | Kazunari Yamaura | K. Yamaura (NIMS, ORNL), M. Arai (NIMS), A. Sato (NIMS), A.B. Karki
(Louisiana State Univ), D.P. Young (Louisiana State Univ), R. Movshovich
(LANL), S. Okamoto (ORNL), D. Mandrus (ORNL), E. Takayama-Muromachi (NIMS) | NaV2O4: a Quasi-1D Metallic Antiferromagnet with Half-Metallic Chains | 14 pages, including 4 figures and 1 table, accepted for publication
in PRL | null | 10.1103/PhysRevLett.99.196601 | null | cond-mat.str-el cond-mat.supr-con | null | NaV2O4 crystals were grown under high pressure using a NaCl flux, and the
crystals were characterized with X-ray diffraction, electrical resistivity,
heat capacity, and magnetization. The structure of NaV2O4 consists of double
chains of edge-sharing VO6 octahedra. The resistivity is highly anisotropic,
with the resistivity perpendicular to the chains more than 20 times greater
than that parallel to the chains. Magnetically, the intrachain interactions are
ferromagnetic and the interchain interactions are antiferromagnetic; 3D
antiferromagnetic order is established at 140 K. First principles electronic
structure calculations indicate that the chains are half metallic.
Interestingly, the case of NaV2O4 seems to be a quasi-1D analogue of what was
found for half-metallic materials.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 00:19:09 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 13:12:45 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Sep 2007 02:21:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yamaura",
"K.",
"",
"NIMS, ORNL"
],
[
"Arai",
"M.",
"",
"NIMS"
],
[
"Sato",
"A.",
"",
"NIMS"
],
[
"Karki",
"A. B.",
"",
"Louisiana State Univ"
],
[
"Young",
"D. P.",
"",
"Louisiana State Univ"
],
[
"Movshovich",
"R.",
"",
"LANL"
],
[
"Okamoto",
"S.",
"",
"ORNL"
],
[
"Mandrus",
"D.",
"",
"ORNL"
],
[
"Takayama-Muromachi",
"E.",
"",
"NIMS"
]
] |
0707.0520 | Molin Liu | Molin Liu, Hongya Liu, Chunxiao Wang, Yongli Ping | The Real Scalar Field Equation for Nariai Black Hole in the 5D
Schwarzschild-de Sitter Black String Space | 10 pages,6 figures.To appear in Int. J. Mod. Phys. A | Int.J.Mod.Phys.A22:4451-4465,2007 | 10.1142/S0217751X07037044 | null | gr-qc | null | The Nariai black hole, whose two horizons are lying close to each other, is
an extreme and important case in the research of black hole. In this paper we
study the evolution of a massless scalar field scattered around in 5D
Schwarzschild-de Sitter black string space. Using the method shown by Brevik
and Simonsen (2001) we solve the scalar field equation as a boundary value
problem, where real boundary condition is employed. Then with convenient
replacement of the 5D continuous potential by square barrier, the reflection
and transmission coefficients ($R, T$) are obtained. At last, we also compare
the coefficients with usual 4D counterpart.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 00:20:31 GMT"
},
{
"version": "v2",
"created": "Sat, 5 Apr 2008 02:30:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liu",
"Molin",
""
],
[
"Liu",
"Hongya",
""
],
[
"Wang",
"Chunxiao",
""
],
[
"Ping",
"Yongli",
""
]
] |
0707.0521 | Luca Rizzi | L. Rizzi, E.V. Held, I. Saviane, R.B. Tully, M. Gullieuszik | The distance to the Fornax Dwarf Spheroidal Galaxy | Accepted for publication on Monthly Notices of the Royal Astronomical
Society | null | 10.1111/j.1365-2966.2007.12196.x | null | astro-ph | null | A large multicolour, wide-field photometric database of the Fornax dwarf
spheroidal galaxy has been analysed using three different methods to provide
revised distance estimates based on stellar populations in different age
intervals. The distance to Fornax was obtained from the Tip of the Red Giant
Branch measured by a new method, and using the luminosity of Horizontal Branch
stars and Red Clump stars correc ted for stellar population effects. Assuming a
reddening $E(B-V)=0.02$, the following distance moduli were derived:
$(m-M)_0=20.71 \pm 0.07$ based on the Tip of the Red Giant Branch,
$(m-M)_0=20.72 \pm 0.06$ from the level of the Horizontal Branch, and
$(m-M)_0=20.73 \pm 0.09$ using the Red Clump method. The weighted mean distance
modulus to Fornax is $(m-M)_0=20.72 \pm 0.04$. All these measurements agree
within the errors, and are fully consistent with previous determinations and
with the distance measurements obtained in a companion paper from near-infrared
colour-magnitude diagrams.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 00:34:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rizzi",
"L.",
""
],
[
"Held",
"E. V.",
""
],
[
"Saviane",
"I.",
""
],
[
"Tully",
"R. B.",
""
],
[
"Gullieuszik",
"M.",
""
]
] |
0707.0522 | Rajesh Chopdekar | Rajesh V. Chopdekar, Elke Arenholz, and Yuri Suzuki | Superconductivity in spinel oxide LiTi2O4 epitaxial thin films | 25 pages, 7 figures, v2 - expanded Fig 1,2,7 with added discussions | Physica C, Volume 469, Issue 21, 1 November 2009, Pages 1885-1891 | 10.1016/j.physc.2009.05.009 | null | cond-mat.supr-con cond-mat.mtrl-sci | null | LiTi2O4 is a unique material in that it is the only known oxide spinel
superconductor. Although bulk studies have demonstrated that superconductivity
can be generally described by the Bardeen-Cooper-Schreiffer theory, the
microscopic mechanisms of superconductivity are not yet resolved fully. The
sensitivity of the superconducting properties to various defects of the spinel
crystal structure provides insight into such mechanisms. Epitaxial films of
LiTi2O4 on single crystalline substrates of MgAl2O4, MgO, and SrTiO3 provide
model systems to systematically explore the effects of lattice strain and
microstructural disorder. Lattice strain that affects bandwidth gives rise to
limited variations in the superconducting and normal state properties.
Microstructural disorder such as antiphase boundaries that give rise to Ti
network disorder can reduce the critical temperature, but Ti network disorder
combined with Mg interdiffusion can affect the superconducting state much more
dramatically. Thickness dependent transport studies indicate a
superconductor-insulator transition as a function of film thickness regardless
of lattice strain and microstructure. In addition, surface sensitive X-ray
absorption spectroscopy has identified Ti to retain site symmetry and average
valence of the bulk material regardless of film thickness.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 01:18:04 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 22:00:54 GMT"
}
] | 2010-05-27T00:00:00 | [
[
"Chopdekar",
"Rajesh V.",
""
],
[
"Arenholz",
"Elke",
""
],
[
"Suzuki",
"Yuri",
""
]
] |
0707.0523 | Pengcheng Li | Pengcheng Li, F. F. Balakirev, R. L. Greene | Upper critical field of electron-doped Pr$_{2-x}$Ce$_x$CuO$_{4-\delta}$
in parallel magnetic fields | 4 pages, 4 figures | Phys. Rev. B 75, 172508 (2007) | 10.1103/PhysRevB.75.172508 | null | cond-mat.supr-con cond-mat.str-el | null | We report a systematic study of the resistive superconducting transition in
the electron-doped cuprates Pr$_{2-x}$Ce$_{x}$CuO$_{4-\delta}$ down to 1.5 K
for magnetic field up to 58 T applied parallel to the conducting ab-planes. We
find that the zero temperature parallel critical field (H$_{c2\parallel
ab}$(0)) exceeds 58 T for the underdoped and optimally-doped films. For the
overdoped films, 58 T is sufficient to suppress the superconductivity. We also
find that the Zeeman energy $\mu_B$H$_{c2\parallel ab}$(0) reaches the
superconducting gap ($\triangle_0$), i.e. $\mu_B$H$_{c2\parallel ab}(0)\simeq
\triangle_0$, for all the dopings, strongly suggesting that the parallel
critical field is determined by the Pauli paramagnetic limit in electron-doped
cuprates.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 01:29:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Li",
"Pengcheng",
""
],
[
"Balakirev",
"F. F.",
""
],
[
"Greene",
"R. L.",
""
]
] |
0707.0524 | Yue-Min Wan | Yue-Min Wan and Heng-Tien Lin | Smart Electromechanical Pumping of Electrons in a Nanopillars Transistor | 17 pages, 5 figures, 1 table | null | null | null | quant-ph | null | Analysis of room-temperature current-voltage (I-V) characteristics of a
silicon box in a nanopillar transistor suggests that a weak electromechanical
coupling of 0.17 is responsible for the stable tunnel of single-electron. The
dynamics involves a few electrons and the numbers (N) specified are periodical
at 3, 6, and 12. Quantized currents are observed at N = 7 and 13, indicating
that the box is a man-made atom. At a large value of 0.5, instability however
dominates the I-V by showing interference, channel closure and the change of
tunnel direction. Overall, the interplay of even and odd electrons between
different channels also shows that the box operates itself like a smart quantum
pump.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 01:38:26 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 01:57:23 GMT"
}
] | 2007-07-24T00:00:00 | [
[
"Wan",
"Yue-Min",
""
],
[
"Lin",
"Heng-Tien",
""
]
] |
0707.0525 | Yuichi Matsuda | Y. Matsuda (1), D. Iono (2), K. Ohta (1), T. Yamada (2 and 3), R.
Kawabe (2), T. Hayashino (3), A. B. Peck (4), G. R. Petitpas (4) ((1) Kyoto
University, (2) National Astronomical Observatory of Japan, (3) Tohoku
University, (4) Harvard-Smithsonian Center for Astrophysics) | High-Resolution Submillimeter Imaging of the Ly-alpha Blob1 in SSA 22 | 7 pages, 5 figures, accepted for publication in ApJ | null | 10.1086/521076 | null | astro-ph | null | We present ~2" resolution submillimeter observations of the submillimeter
luminous giant Ly-alpha blob (LAB1) in the SSA 22 protocluster at redshift
z=3.1 with the Submillimeter Array (SMA). Although the expected submillimeter
flux density is 16 mJy at 880 micron, no emission is detected with the 2".4 x
1".9 (18 x 14 kpc) beam at the 3 sigma level of 4.2 mJy beam^{-1} in the SMA
field of view of 35". This is in contrast to the previous lower angular
resolution (15") observations where a bright (17 mJy) unresolved submillimeter
source was detected at 850 micron toward the LAB1 using the Submillimeter
Common-User Bolometer Array on the James Clerk Maxwell Telescope. The SMA
non-detection suggests that the spatial extent of the submillimeter emission of
LAB1 should be larger than 4" (>30 kpc). The most likely interpretation of the
spatially extended submillimeter emission is that starbursts occur throughout
the large area in LAB1. Some part of the submillimeter emission may come from
spatially extended dust expelled from starburst regions by galactic superwind.
The spatial extent of the submillimeter emission of LAB1 is similar to those of
high redshift radio galaxies rather than submillimeter galaxies.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 02:09:36 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 04:55:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Matsuda",
"Y.",
"",
"2 and 3"
],
[
"Iono",
"D.",
"",
"2 and 3"
],
[
"Ohta",
"K.",
"",
"2 and 3"
],
[
"Yamada",
"T.",
"",
"2 and 3"
],
[
"Kawabe",
"R.",
""
],
[
"Hayashino",
"T.",
""
],
[
"Peck",
"A. B.",
""
],
[
"Petitpas",
"G. R.",
""
]
] |
0707.0526 | Fuquan Fang | Fuquan Fang, Xiangdong Li, Zhenlei Zhang | Two generalizations of Cheeger-Gromoll splitting theorem via
Bakry-\'{E}mery Ricci curvature | 14 pages | null | null | null | math.DG math.GT | null | In this paper, we prove two generalized versions of the Cheeger-Gromoll
splitting theorem via the non-negativity of the Bakry-\'Emery Ricci curavture
on complete Riemannian manifolds.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 01:43:36 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2007 01:00:58 GMT"
}
] | 2007-07-10T00:00:00 | [
[
"Fang",
"Fuquan",
""
],
[
"Li",
"Xiangdong",
""
],
[
"Zhang",
"Zhenlei",
""
]
] |
0707.0527 | Valentino Tosatti | Valentino Tosatti | A general Schwarz Lemma for almost-Hermitian manifolds | 21 pages; v2 added some remarks and references; v3 fixed typos, final
version to appear in Communications in Analysis and Geometry | Comm. Anal. Geom. 15 (2007), no.5, 1063-1086 | 10.4310/CAG.2007.v15.n5.a6 | null | math.DG | null | We prove a version of Yau's Schwarz Lemma for general almost-complex
manifolds equipped with Hermitian metrics. This requires an extension to this
setting of the Laplacian comparison theorem. As an application we show that the
product of two almost-complex manifolds does not admit any complete Hermitian
metric with bisectional curvature bounded between two negative constants that
satisfies some additional mild assumptions.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 02:06:49 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jul 2007 09:36:46 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Sep 2007 17:13:57 GMT"
}
] | 2014-01-21T00:00:00 | [
[
"Tosatti",
"Valentino",
""
]
] |
0707.0528 | Hideki Maeda | Tomohiro Harada, Hideki Maeda and B.J. Carr | Self-similar cosmological solutions with dark energy. I: formulation and
asymptotic analysis | 13 pages, 3 figures, 2 tables, final version to appear Physical
Review D | Phys.Rev.D77:024022,2008 | 10.1103/PhysRevD.77.024022 | CECS-PHY-07/15 | gr-qc astro-ph hep-th | null | Based on the asymptotic analysis of ordinary differential equations, we
classify all spherically symmetric self-similar solutions to the Einstein
equations which are asymptotically Friedmann at large distances and contain a
perfect fluid with equation of state $p=(\gamma -1)\mu$ with $0<\gamma<2/3$.
This corresponds to a ``dark energy'' fluid and the Friedmann solution is
accelerated in this case due to anti-gravity. This extends the previous
analysis of spherically symmetric self-similar solutions for fluids with
positive pressure ($\gamma>1$). However, in the latter case there is an
additional parameter associated with the weak discontinuity at the sonic point
and the solutions are only asymptotically ``quasi-Friedmann'', in the sense
that they exhibit an angle deficit at large distances. In the $0<\gamma<2/3$
case, there is no sonic point and there exists a one-parameter family of
solutions which are {\it genuinely} asymptotically Friedmann at large
distances. We find eight classes of asymptotic behavior: Friedmann or
quasi-Friedmann or quasi-static or constant-velocity at large distances,
quasi-Friedmann or positive-mass singular or negative-mass singular at small
distances, and quasi-Kantowski-Sachs at intermediate distances. The
self-similar asymptotically quasi-static and quasi-Kantowski-Sachs solutions
are analytically extendible and of great cosmological interest. We also
investigate their conformal diagrams. The results of the present analysis are
utilized in an accompanying paper to obtain and physically interpret numerical
solutions.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 02:46:52 GMT"
},
{
"version": "v2",
"created": "Sat, 6 Oct 2007 01:46:57 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Jan 2008 18:59:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Harada",
"Tomohiro",
""
],
[
"Maeda",
"Hideki",
""
],
[
"Carr",
"B. J.",
""
]
] |
0707.0529 | Zhi-Ming Zhang | Jian Yang, Ya-Fei Yu, Zhi-Ming Zhang | Realization of universal quantum cloning with SQUID qubits in a cavity | 4 pages, 2 figures | null | 10.1103/PhysRevA.77.034302 | null | quant-ph | null | We propose a scheme to realize $1\to 2$ universal quantum cloning machine
(UQCM) with superconducting quantum interference device (SQUID) qubits, embeded
in a high-Q cavity. CNOT operations are derived to present our scheme, and the
two-photon Raman resonance processes are used to increase the operation rate.
Compared with previous works, our scheme has advantages in the experimental
realization and further utilization.
| [
{
"version": "v1",
"created": "Wed, 4 Jul 2007 02:42:21 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jul 2007 11:23:25 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Yang",
"Jian",
""
],
[
"Yu",
"Ya-Fei",
""
],
[
"Zhang",
"Zhi-Ming",
""
]
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.