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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0708.2249 | Philipp Hagler | D. Br\"ommel, M. Diehl, M. G\"ockeler, Ph. H\"agler, R. Horsley, Y.
Nakamura, D. Pleiter, P.E.L. Rakow, A. Sch\"afer, G. Schierholz, H. St\"uben
and J. M. Zanotti (for the QCDSF collaboration and UKQCD collaboration) | The spin structure of the pion | 4 pages, 6 figures; journal version (with original Fig.1 included);
updated abstract, text and Figs. 3, 4, 5, 6; added reference; conclusions
unchanged | Phys.Rev.Lett.101:122001,2008 | 10.1103/PhysRevLett.101.122001 | DESY 07-120, Edinburgh 2007/13, LTH 754, TUM/T39-07-12 | hep-lat hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present the first calculation of the transverse spin structure of the pion
in lattice QCD. Our simulations are based on two flavors of non-perturbatively
improved Wilson fermions, with pion masses as low as 400 MeV in volumes up to
(2.1 fm)^3 and lattice spacings below 0.1 fm. We find a characteristic
asymmetry in the spatial distribution of transversely polarized quarks. This
asymmetry is very similar in magnitude to the analogous asymmetry we previously
obtained for quarks in the nucleon. Our results support the hypothesis that all
Boer-Mulders functions are alike.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:36:48 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Aug 2009 14:02:11 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Brömmel",
"D.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Diehl",
"M.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Göckeler",
"M.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Hägler",
"Ph.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Horsley",
"R.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Nakamura",
"Y.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Pleiter",
"D.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Rakow",
"P. E. L.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Schäfer",
"A.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Schierholz",
"G.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Stüben",
"H.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
],
[
"Zanotti",
"J. M.",
"",
"for the QCDSF collaboration and UKQCD collaboration"
]
] |
0708.2250 | Nikolaos Mavromatos | Nikolaos E. Mavromatos (King's College London) | Lorentz Invariance Violation from String Theory | 26 pages Latex, uses special macros, three eps figures incorporated.
Invited talk at the International Workshop ``From Quantum to Emergent
Gravity: Theory and Phenomenology'', SISSA, Trieste (Italy), June 11-15 2007 | PoS QG-Ph:027,2007 | null | null | hep-th gr-qc hep-ph | null | In this brief, and by no means complete, review I discuss situations in
string theory, in which Lorentz Invariance Violation may occur in a way
consistent with world-sheet conformal invariance, thereby leading to
acceptable, in principle, string backgrounds. In particular, I first discuss
spontaneous Lorentz violation in (non supersymmetric) open string field theory.
Then, I move onto a discussion of gravity-induced modified dispersion relations
in non-critical (Liouville) strings, in the sense of an induced Finsler-like
geometry depending on both coordinates and momenta, for string propagation in
non-trivial space times (such as D-particle ``foamy situations''). I pay
attention to explaining the appearance of bi-metric models from such string
theories, which could serve as examples of alternative scenaria to dark matter.
Finally, I make some comparisons with similar developments in other contexts,
such as critical strings in non-commutative space times, as well as deformed
special relativities and theories with reduced Lorentz symmetry, advocated
recently, where again Finsler geometry seems to come into play. In this latter
respect, I put the emphasis on phenomenology and attempt to answer the question
as to whether there is the possibility of experimental disentanglement of the
various approaches.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:32:45 GMT"
}
] | 2009-05-07T00:00:00 | [
[
"Mavromatos",
"Nikolaos E.",
"",
"King's College London"
]
] |
0708.2251 | Marco Pallavicini | Borexino Collaboration | First real time detection of Be7 solar neutrinos by Borexino | Paper submitted to PRLB. 9 pages, 6 figures (EPS) PDF files included
into tar.gz file, together with LaTeX source, eps figs and style files | Phys.Lett.B658:101-108,2008 | 10.1016/j.physletb.2007.09.054 | null | astro-ph hep-ph nucl-ex | null | This paper reports a direct measurement of the Be7 solar neutrino signal rate
performed with the Borexino low background liquid scintillator detector. This
is the first real-time spectral measurement of sub-MeV solar neutrinos. The
result for 0.862 MeV Be7 is 47 +- 7 (stat} +- 12 (sys} counts/(day x 100 ton),
consistent with predictions of Standard Solar Models and neutrino oscillations
with LMA-MSW parameters.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:33:57 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 16:46:43 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"Borexino Collaboration",
"",
""
]
] |
0708.2252 | Dale Miller | Chuck Liang, Dale Miller (INRIA Futurs) | Focusing and Polarization in Intuitionistic Logic | null | Dans Computer Science Logic (2007) | null | null | cs.LO | null | A focused proof system provides a normal form to cut-free proofs that
structures the application of invertible and non-invertible inference rules.
The focused proof system of Andreoli for linear logic has been applied to both
the proof search and the proof normalization approaches to computation. Various
proof systems in literature exhibit characteristics of focusing to one degree
or another. We present a new, focused proof system for intuitionistic logic,
called LJF, and show how other proof systems can be mapped into the new system
by inserting logical connectives that prematurely stop focusing. We also use
LJF to design a focused proof system for classical logic. Our approach to the
design and analysis of these systems is based on the completeness of focusing
in linear logic and on the notion of polarity that appears in Girard's LC and
LU proof systems.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:36:28 GMT"
}
] | 2007-08-17T00:00:00 | [
[
"Liang",
"Chuck",
"",
"INRIA Futurs"
],
[
"Miller",
"Dale",
"",
"INRIA Futurs"
]
] |
0708.2253 | Puru Gujrati | P. D. Gujrati and Bradley Lambeth Jr | The Concept of Entropy and its Concavity for a Finite Protein in its
Environment: An exact study on a Square Lattice | 4 pages, 2 figures | null | null | UATP/07-02 | cond-mat.soft cond-mat.other | null | We consider a general lattice model of a finite protein in its environment
and calculate its Boltzmann entropy SB(E) as a function of its energy E in a
microcanonical ensemble, and Gibbs entropy SG(E) as a function of its average
energy E in a canonical ensemble by exact enumeration on a square lattice. We
find that because of the finite size of the protein, (i) the two are very
different and SG(E)>SB(E), (ii) SB(E) need not be concave while SG(E) is, and
(iii) SG(E) is relevant for experiments but not SB(E), even though SB(E) is
conceptually more useful. We discuss the consequences of these differences. The
results are general and applicable to all finite systems.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:44:35 GMT"
}
] | 2007-08-17T00:00:00 | [
[
"Gujrati",
"P. D.",
""
],
[
"Lambeth",
"Bradley",
"Jr"
]
] |
0708.2254 | Michael Buchoff | Paulo F. Bedaque, Michael I. Buchoff, Andre Walker-Loud | Effective Field Theory for the Anisotropic Wilson Lattice Action | 17 pages, 1 figure | Phys.Rev.D77:074501,2008 | 10.1103/PhysRevD.77.074501 | UMD-40762-393 | hep-lat | null | We construct the effective field theory appropriate for describing the low
energy behavior of anisotropic Wilson lattice actions and the O(a) improved
variant thereof. We then apply this effective field theory to the hadron
spectrum and dispersion relations, focussing on the corrections due to the
anisotropy. We point out an important feature of anisotropic lattices regarding
the Aoki-regime; for a given set of fermion masses and spatial lattice spacing,
if an isotropic action is in the QCD-phase, this does not guarantee that the
anisotropic action is outside the Aoki-regime. This may be important in the
tuning of bare parameters for anisotropic lattices using domain-wall and
overlap fermions as well as Wilson and O(a)-improved Wilson fermions.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:55:14 GMT"
}
] | 2008-06-16T00:00:00 | [
[
"Bedaque",
"Paulo F.",
""
],
[
"Buchoff",
"Michael I.",
""
],
[
"Walker-Loud",
"Andre",
""
]
] |
0708.2255 | Jeremy Siek | Jeremy G. Siek and Andrew Lumsdaine | A Language for Generic Programming in the Large | 50 pages | null | null | null | cs.PL cs.SE | null | Generic programming is an effective methodology for developing reusable
software libraries. Many programming languages provide generics and have
features for describing interfaces, but none completely support the idioms used
in generic programming. To address this need we developed the language G. The
central feature of G is the concept, a mechanism for organizing constraints on
generics that is inspired by the needs of modern C++ libraries. G provides
modular type checking and separate compilation (even of generics). These
characteristics support modular software development, especially the smooth
integration of independently developed components. In this article we present
the rationale for the design of G and demonstrate the expressiveness of G with
two case studies: porting the Standard Template Library and the Boost Graph
Library from C++ to G. The design of G shares much in common with the concept
extension proposed for the next C++ Standard (the authors participated in its
design) but there are important differences described in this article.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:06:18 GMT"
}
] | 2007-08-17T00:00:00 | [
[
"Siek",
"Jeremy G.",
""
],
[
"Lumsdaine",
"Andrew",
""
]
] |
0708.2256 | Anton Klyachko | Anton A. Klyachko | Automorphisms and isomorphisms of Chevalley groups and algebras | 8 pages. A Russian version of this paper is at
http://mech.math.msu.su/department/algebra/staff/klyachko/papers.htm . V4:
minor changes in Introduction and References | Journal of Algebra, 2010, 324:10, 2608-2619 | 10.1016/j.jalgebra.2009.08.024 | null | math.GR math.RA math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | An adjoint Chevalley group of rank at least 2 over a rational algebra (or a
similar ring), its elementary subgroup, and the corresponding Lie ring have the
same automorphism group. These automorphisms are explicitly described.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 17:56:22 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 14:20:05 GMT"
},
{
"version": "v3",
"created": "Wed, 7 Nov 2007 19:32:41 GMT"
},
{
"version": "v4",
"created": "Sun, 2 Aug 2009 21:13:37 GMT"
}
] | 2010-09-29T00:00:00 | [
[
"Klyachko",
"Anton A.",
""
]
] |
0708.2257 | Nicholas Cummings | Nick Cummings, B. L. Hu | Dynamics of Atom-Field Entanglement from Exact Solutions: Towards Strong
Coupling and Non-Markovian Regimes | 12 pages, 5 figures; minor changes in grammar, wording, and
formatting. One unnecessary figure removed. Figure number revised (no longer
counts subfigures separately) | Phys. Rev. A 77, 053823 (2008) | 10.1103/PhysRevA.77.053823 | null | quant-ph | null | We examine the dynamics of bipartite entanglement between a two-level atom
and the electromagnetic field. We treat the Jaynes-Cummings model with a single
field mode and examine in detail the exact time evolution of entanglement,
including cases where the atomic state is initially mixed and the atomic
transition is detuned from resonance. We then explore the effects of other
nearby modes by calculating the exact time evolution of entanglement in more
complex systems with two, three, and five field modes. For these cases we can
obtain exact solutions which include the strong coupling regimes. Finally, we
consider the entanglement of a two-level atom with the infinite collection of
modes present in the intracavity field of a Fabre-Perot cavity. In contrast to
the usual treatment of atom-field interactions with a continuum of modes using
the Born-Markov approximation, our treatment in all cases describes the full
non-Markovian dynamics of the atomic subsystem. Only when an analytic
expression for the infinite mode case is desired do we need to make a weak
coupling assumption which at long times approximates Markovian dynamics.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:53:19 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Oct 2007 17:25:15 GMT"
}
] | 2010-10-04T00:00:00 | [
[
"Cummings",
"Nick",
""
],
[
"Hu",
"B. L.",
""
]
] |
0708.2258 | Kishore Ananda N | Kishore N. Ananda, S. Carloni and P. K. S. Dunsby | The evolution of cosmological gravitational waves in f(R) gravity | 19 pages, 4 figures; v2: corrected to match version accepted for
publication in PRD | Phys.Rev.D77:024033,2008 | 10.1103/PhysRevD.77.024033 | null | gr-qc astro-ph | null | We give a rigorous and mathematically clear presentation of the Covariant and
Gauge Invariant theory of gravitational waves in a perturbed
Friedmann-Lemaitre-Robertson-Walker universe for Fourth Order Gravity, where
the matter is described by a perfect fluid with a barotropic equation of state.
As an example of a consistent analysis of tensor perturbations in Fourth Order
Gravity, we apply the formalism to a simple background solution of R^n gravity.
We obtain the exact solutions of the perturbation equations for scales much
bigger than and smaller than the Hubble radius. It is shown that the evolution
of tensor modes is highly sensitive to the choice of n and an interesting new
feature arises. During the radiation dominated era, their exist a growing
tensor perturbation for nearly all choices of n. This occurs even when the
background model is undergoing accelerated expansion as opposed to the case of
General Relativity. Consequently, cosmological gravitational wave modes can in
principle provide a strong constraint on the theory of gravity independent of
other cosmological data sets.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:03:15 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 15:37:50 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ananda",
"Kishore N.",
""
],
[
"Carloni",
"S.",
""
],
[
"Dunsby",
"P. K. S.",
""
]
] |
0708.2259 | Mathew James Page | T. S. Poole, A. A. Breeveld, M. J. Page, W. Landsman, S. T. Holland,
P. Roming, N. P. M. Kuin, P. J. Brown, C. Gronwall, S. Hunsberger, S. Koch,
K. O. Mason, P. Schady, D. Vanden Berk, A. J. Blustin, P. Boyd, P. Broos, M.
Carter, M. M. Chester, A. Cucchiara, B. Hancock, H. Huckle, S. Immler, M.
Ivanushkina, T. Kennedy, F. Marshall, A. Morgan, S. Pandey, M. de Pasquale,
P. J. Smith, M. Still | Photometric Calibration of the Swift Ultraviolet/Optical Telescope | Minor improvements after referees report. Accepted for publication in
MNRAS | Mon.Not.Roy.Astron.Soc.383:627-645,2008 | 10.1111/j.1365-2966.2007.12563.x | null | astro-ph | null | We present the photometric calibration of the Swift UltraViolet/Optical
Telescope (UVOT) which includes: optimum photometric and background apertures,
effective area curves, colour transformations, conversion factors for count
rates to flux, and the photometric zero points (which are accurate to better
than 4 per cent) for each of the seven UVOT broadband filters. The calibration
was performed with observations of standard stars and standard star fields that
represent a wide range of spectral star types. The calibration results include
the position dependent uniformity, and instrument response over the 1600-8000A
operational range. Because the UVOT is a photon counting instrument, we also
discuss the effect of coincidence loss on the calibration results. We provide
practical guidelines for using the calibration in UVOT data analysis. The
results presented here supersede previous calibration results.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:05:28 GMT"
},
{
"version": "v2",
"created": "Fri, 9 Nov 2007 10:49:32 GMT"
}
] | 2010-11-09T00:00:00 | [
[
"Poole",
"T. S.",
""
],
[
"Breeveld",
"A. A.",
""
],
[
"Page",
"M. J.",
""
],
[
"Landsman",
"W.",
""
],
[
"Holland",
"S. T.",
""
],
[
"Roming",
"P.",
""
],
[
"Kuin",
"N. P. M.",
""
],
[
"Brown",
"P. J.",
""
],
[
"Gronwall",
"C.",
""
],
[
"Hunsberger",
"S.",
""
],
[
"Koch",
"S.",
""
],
[
"Mason",
"K. O.",
""
],
[
"Schady",
"P.",
""
],
[
"Berk",
"D. Vanden",
""
],
[
"Blustin",
"A. J.",
""
],
[
"Boyd",
"P.",
""
],
[
"Broos",
"P.",
""
],
[
"Carter",
"M.",
""
],
[
"Chester",
"M. M.",
""
],
[
"Cucchiara",
"A.",
""
],
[
"Hancock",
"B.",
""
],
[
"Huckle",
"H.",
""
],
[
"Immler",
"S.",
""
],
[
"Ivanushkina",
"M.",
""
],
[
"Kennedy",
"T.",
""
],
[
"Marshall",
"F.",
""
],
[
"Morgan",
"A.",
""
],
[
"Pandey",
"S.",
""
],
[
"de Pasquale",
"M.",
""
],
[
"Smith",
"P. J.",
""
],
[
"Still",
"M.",
""
]
] |
0708.2260 | Guglielmo De Nardo | The BABAR Collaboration: B. Aubert, et al | A search for B+ --> tau+ nu with Hadronic B tags | 8 pages, 2 figures, submitted to Physics Review D - Rapid
Communications | Phys.Rev.D77:011107,2008 | 10.1103/PhysRevD.77.011107 | BABAR-PUB-07/046, SLAC-PUB-12736 | hep-ex | null | We present a search for the decay B^+ --> tau^+ nu using $383 \times 10^{6}}$
BBbar pairs collected at the Upsilon(4S) resonance with the BABAR detector at
the SLAC PEP-II B Factory. We select a sample of events with one completely
reconstructed tag B in a hadronic decay mode ($B^- \to D^{(*)0} X^-$), and
examine the rest of the event to search for a B^+ --> tau^+ nu decay. We
identify the tau lepton in the following modes: tau^+ --> e^+ nu nu,tau^+ -->
mu^+ nu nu, tau^+ --> pi^+ nu and tau^+ --> pi^+ pi^0 nu. We find a 2.2 sigma
excess in data and measure a branching fraction of B(B+ --> tau^+ nu) =
(1.8^{+0.9}_{-0.8}(stat.) \pm 0.4(bkg. syst.) \pm 0.2 (other syst.)) \times
10^{4}. We calculate the product of the B meson decay constant f_{B} and
|V_{ub}| to be f_{B} |V_{ub}| =
(10.1^{+2.3}_{-2.5}(stat.)^{+1.2}_{-1.5}(syst.))\times10^{-4} GeV
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:08:52 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0708.2261 | Pierre Kaufmann | R. Marcon (IFGW/Unicamp, Brazil), P. Kaufmann (Mackenzie and Unicamp,
Brazil), A. M. Melo (Mackenzie and Unicamp, Brazil), A. S. Kudaka (Mackenzie,
Brazil), E. Tandberg-Hanssen (CSPAR, Univ.Alabama, Huntsville, USA) | Association of mid-infrared solar plages with Calcium K line emissions
and magnetic structures | 5 pages, 4 figures. Accepted by PASP | vol. 120,pp. 16-19, 2008 | 10.1086/525058 | null | astro-ph | null | Solar mid-IR observations in the 8-15 micrometer band continuum with moderate
angular resolution (18 arcseconds) reveal the presence of bright structures
surrounding sunspots. These plage-like features present good association with
calcium CaII K1v plages and active region magnetograms. We describe a new
optical setup with reflecting mirrors to produce solar images on the focal
plane array of uncooled bolometers of a commercial camera preceded by germanium
optics. First observations of a sunspot on September 11, 2006 show a mid-IR
continuum plage exhibiting spatial distribution closely associated with CaII
K1v line plage and magnetogram structures. The mid-IR continuum bright plage is
about 140 K hotter than the neighboring photospheric regions, consistent with
hot plasma confined by the magnetic spatial structures in and above the active
region
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:11:07 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Oct 2007 15:15:08 GMT"
},
{
"version": "v3",
"created": "Tue, 30 Oct 2007 18:37:02 GMT"
}
] | 2008-04-18T00:00:00 | [
[
"Marcon",
"R.",
"",
"IFGW/Unicamp, Brazil"
],
[
"Kaufmann",
"P.",
"",
"Mackenzie and Unicamp,\n Brazil"
],
[
"Melo",
"A. M.",
"",
"Mackenzie and Unicamp, Brazil"
],
[
"Kudaka",
"A. S.",
"",
"Mackenzie,\n Brazil"
],
[
"Tandberg-Hanssen",
"E.",
"",
"CSPAR, Univ.Alabama, Huntsville, USA"
]
] |
0708.2262 | Richard Herrmann | Richard Herrmann | Gauge invariance in fractional field theories | remarks on fractional spin added, references added, in press
Phys.Lett.A | Phys.Lett.A372:5515-5522,2008 | 10.1016/j.physleta.2008.06.063 | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The principle of local gauge invariance is applied to fractional wave
equations and the interaction term is determined up to order $o(\bar{g})$ in
the coupling constant $\bar{g}$. As a first application, based on the
Riemann-Liouville fractional derivative definition, the fractional Zeeman
effect is used to reproduce the baryon spectrum accurately.
The transformation properties of the non relativistic fractional
Schr\"odinger-equation under spatial rotations are investigated and an internal
fractional spin is deduced.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:15:09 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Jul 2008 10:29:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Herrmann",
"Richard",
""
]
] |
0708.2263 | John Middleditch | John Middleditch | The SN 1987A Link to Others and Gamma-Ray Bursts | 13 pages, 2 figures, will be shortened and submitted to ApJ Letters.
V3, fixed refereces, footnote 3 "There are four ..." V4, collimation factor >
10^4, fastest particles > 0.9c, 24 light-days PBF -- a needed candidate for
the r-process. V5 "far side (southern)" ">0.9 c" "shows how" "Mystery Spot"
v6: mag 5.8, the same as Halpha on days 30, 38, and 50. v7 fig, refs change | null | null | LA-UR-06-5685 | astro-ph | null | Early measurements of SN 1987A can be interpreted in light of a beam/jet
(BJ), with a collimation factor >10,000, which impacted polar ejecta (PE) to
produce the "Mystery Spot" (MS), ~24 lt-d away. Other details of SN 1987A
suggest that it came from a merger of 2 stellar cores of a common envelope (CE)
binary, i.e. a "double degenerate" (DD) SN. Even having to penetrate the CE,
the BJ may have caused a long-soft (l)GRB upon hitting the PE, thus DD can
produce lGRBs. Because DD must be the dominant merger/SN mechanism in
elliptical galaxies (EGs), where only short, hard GRBs (sGRBs) have been
observed, DD without CE or PE must also produce sGRBs, and thus NS-NS mergers
may not make GRBs as we know them, and/or be as common as previously thought.
Millisecond pulsars (MSPs) in the non-core-collapsed globular clusters are also
99% DD-formed from WD-WD merger, consistent with their 2.10 ms minimum spin
period, the 2.14 ms signal seen from SN 1987A, and sGRBs offset from the
centers of EGs. The details of Ia's suggest that these are also DD, and the
total thermonuclear disruption paradigm is now in serious doubt as well, a
cause for concern in Ia Cosmology, because Ia's will appear to be Ic's when
viewed from their DD merger poles, given sufficient matter above that lost to
core-collapse. As a DD SN, 1987A appears to be the Rosetta Stone for 99% of
SNe, GRBs and MSPs, including all recent nearby SNe except SN 1986J, and the
more distant SN 2006gy. There is no need to invent exotica, such as
"collapsars," to account for GRBs.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:19:45 GMT"
},
{
"version": "v2",
"created": "Sun, 26 Aug 2007 05:23:12 GMT"
},
{
"version": "v3",
"created": "Mon, 17 Sep 2007 21:35:57 GMT"
},
{
"version": "v4",
"created": "Tue, 13 Nov 2007 20:34:49 GMT"
},
{
"version": "v5",
"created": "Tue, 20 Nov 2007 22:12:15 GMT"
},
{
"version": "v6",
"created": "Mon, 3 Dec 2007 20:08:52 GMT"
},
{
"version": "v7",
"created": "Wed, 16 Jan 2008 22:25:16 GMT"
},
{
"version": "v8",
"created": "Wed, 6 Feb 2008 23:02:49 GMT"
}
] | 2008-02-07T00:00:00 | [
[
"Middleditch",
"John",
""
]
] |
0708.2264 | George Palasantzas | P. J. van Zwol, G. Palasantzas and J. Th. M. De Hosson | Influence of random roughness on the adhesion between metal surfaces due
to capillary condensation | 8 pages, 3 figures, To appear in Appl. Phys. Lett. (2007) | null | 10.1063/1.2768919 | null | cond-mat.mtrl-sci | null | The capillary force was measured by atomic force microscopy between a gold
coated sphere mounted on a cantilever and gold surfaces with different
roughness. For smooth surfaces the capillary adhesive force surpasses in
magnitude any dispersion, e.g. van der Waals/Casimir, and/or electrostatic
forces. A substantial decrease in the capillary force was observed by
increasing the roughness ampltitude a few nanometers between 1-10 nm. From
these measurements two limits can be defined: a smooth limit where a closely
macroscopic size contact surface interacts through the capillary force, and the
rough limit where only a few asperities give a capillary contribution.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:20:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"van Zwol",
"P. J.",
""
],
[
"Palasantzas",
"G.",
""
],
[
"De Hosson",
"J. Th. M.",
""
]
] |
0708.2265 | Hans J. Haubold | R. K. Saxena, A. M. Mathai, H. J. Haubold | Solutions of fractional reaction-diffusion equations in terms of
Mittag-Leffler functions | 22 pages, LaTeX | International Journal of Scientific Research 15 (2006) 1-17 | null | null | math.CA math-ph math.MP | null | This paper deals with the solution of unified fractional reaction-diffusion
systems. The results are obtained in compact and elegant forms in terms of
Mittag-Leffler functions and generalized Mittag-Leffler functions, which are
suitable for numerical computation. On account of the most general character of
the derived results, numerous results on fractional reaction, fractional
diffusion, and fractional reaction-diffusion problems scattered in the
literature, including the recently derived results by the authors for
reaction-diffusion models, follow as special cases.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:23:20 GMT"
}
] | 2014-09-11T00:00:00 | [
[
"Saxena",
"R. K.",
""
],
[
"Mathai",
"A. M.",
""
],
[
"Haubold",
"H. J.",
""
]
] |
0708.2266 | Kai Pan | Pan Kai, Tan Yue and Jiang Sheng | The study of a new gerrymandering methodology | 23 pages,15 figures, 2007 American mathematical modeling contest
"Meritorious Winner" | null | null | null | cs.CY | null | This paper is to obtain a simple dividing-diagram of the congressional
districts, where the only limit is that each district should contain the same
population if possibly. In order to solve this problem, we introduce three
different standards of the "simple" shape. The first standard is that the final
shape of the congressional districts should be of a simplest figure and we
apply a modified "shortest split line algorithm" where the factor of the same
population is considered only. The second standard is that the gerrymandering
should ensure the integrity of the current administrative area as the
convenience for management. Thus we combine the factor of the administrative
area with the first standard, and generate an improved model resulting in the
new diagram in which the perimeters of the districts are along the boundaries
of some current counties. Moreover, the gerrymandering should consider the
geographic features.The third standard is introduced to describe this
situation. Finally, it can be proved that the difference between the supporting
ratio of a certain party in each district and the average supporting ratio of
that particular party in the whole state obeys the Chi-square distribution
approximately. Consequently, we can obtain an archetypal formula to check
whether the gerrymandering we propose is fair.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:44:53 GMT"
}
] | 2007-08-17T00:00:00 | [
[
"Kai",
"Pan",
""
],
[
"Yue",
"Tan",
""
],
[
"Sheng",
"Jiang",
""
]
] |
0708.2267 | D. S. Berman | David S. Berman, Neil B. Copland and Daniel C. Thompson | Background Field Equations for the Duality Symmetric String | 26 pages, latex, v2 typos corrected | Nucl.Phys.B791:175-191,2008 | 10.1016/j.nuclphysb.2007.09.021 | QMUL-PH-2007-15 | hep-th | null | This paper describes the background field equations for strings in T-duality
symmetric formalisms in which the dimension of target space is doubled and the
sigma model supplemented with constraints. These are calculated by demanding
the vanishing of the beta-functional of the sigma model couplings in the
doubled target space. We demonstrate the equivalence with the background field
equations of the standard string sigma model.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 18:52:31 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 07:56:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Berman",
"David S.",
""
],
[
"Copland",
"Neil B.",
""
],
[
"Thompson",
"Daniel C.",
""
]
] |
0708.2268 | Andreas Gathmann | Andreas Gathmann, Michael Kerber, Hannah Markwig | Tropical fans and the moduli spaces of tropical curves | minor corrections to match published version | Compos. Math. 145 (2009) no. 1, 173-195 | 10.1112/S0010437X08003837 | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give a rigorous definition of tropical fans (the "local building blocks
for tropical varieties") and their morphisms. For such a morphism of tropical
fans of the same dimension we show that the number of inverse images (counted
with suitable tropical multiplicities) of a point in the target does not depend
on the chosen point - a statement that can be viewed as the beginning of a
tropical intersection theory. As an application we consider the moduli spaces
of rational tropical curves (both abstract and in some R^r) together with the
evaluation and forgetful morphisms. Using our results this gives new, easy, and
unified proofs of various tropical independence statements, e.g. of the fact
that the numbers of rational tropical curves (in any R^r) through given points
are independent of the points.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:00:58 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Nov 2009 17:52:37 GMT"
}
] | 2014-01-14T00:00:00 | [
[
"Gathmann",
"Andreas",
""
],
[
"Kerber",
"Michael",
""
],
[
"Markwig",
"Hannah",
""
]
] |
0708.2269 | Maria-Cristina Ciocci MC Ciocci | Henk W. Broer, M. Cristina Ciocci, Heinz Han{\ss}mann, Andr\'e
Vanderbauwhede | Quasi-periodic stability of normally resonant tori | null | null | null | null | math.DS | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study quasi-periodic tori under a normal-internal resonance, possibly with
multiple eigenvalues. Two non-degeneracy conditions play a role. The first of
these generalizes invertibility of the Floquet matrix and prevents drift of the
lower dimensional torus. The second condition involves a Kolmogorov-like
variation of the internal frequencies and simultaneously versality of the
Floquet matrix unfolding. We focus on the reversible setting, but our results
carry over to the Hamiltonian and dissipative contexts.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:14:55 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Aug 2007 10:49:43 GMT"
},
{
"version": "v3",
"created": "Fri, 5 Dec 2008 11:23:15 GMT"
}
] | 2008-12-05T00:00:00 | [
[
"Broer",
"Henk W.",
""
],
[
"Ciocci",
"M. Cristina",
""
],
[
"Hanßmann",
"Heinz",
""
],
[
"Vanderbauwhede",
"André",
""
]
] |
0708.2270 | Tan Wong | Saravanan Vijayakumaran, Tan F. Wong and Tat M. Lok | Capacity of the Degraded Half-Duplex Relay Channel | 10 pages, 2 figures | null | null | null | cs.IT math.IT | null | A discrete memoryless half-duplex relay channel is constructed from a
broadcast channel from the source to the relay and destination and a multiple
access channel from the source and relay to the destination. When the relay
listens, the channel operates in the broadcast mode. The channel switches to
the multiple access mode when the relay transmits. If the broadcast component
channel is physically degraded, the half-duplex relay channel will also be
referred to as physically degraded. The capacity of this degraded half-duplex
relay channel is examined. It is shown that the block Markov coding suggested
in the seminal paper by Cover and El Gamal can be modified to achieve capacity
for the degraded half-duplex relay channel. In the code construction, the
listen-transmit schedule of the relay is made to depend on the message to be
sent and hence the schedule carries information itself. If the schedule is
restricted to be deterministic, it is shown that the capacity can be achieved
by a simple management of information flows across the broadcast and multiple
access component channels.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:36:03 GMT"
}
] | 2007-08-17T00:00:00 | [
[
"Vijayakumaran",
"Saravanan",
""
],
[
"Wong",
"Tan F.",
""
],
[
"Lok",
"Tat M.",
""
]
] |
0708.2271 | Vladislav V. Kravchenko | Vladislav V. Kravchenko | Solution of the equation d/dx(pdu/dx)+qu=cu by a solution of the
equation d/dx(pdu/dx)+qu=0 | null | Published under the title: A representation for solutions of the
Sturm-Liouville equation. Complex Variables and Elliptic Problems, 2008, v.
53, No. 8, 775-789 | null | null | math-ph math.MP | null | We give a simple solution of the equation d/dx(pdu/dx)+qu=cu whenever a
nontrivial solution of d/dx(pdu/dx)+qu=0 is known. The method developed for
obtaining this result is based on the theory of pseudoanalytic functions and
their relationship with solutions of the stationary two-dimensional Schrodinger
equation. The final result, that is the formula for the general solution of the
equation d/dx(pdu/dx)+qu=cu has a simple and easily verifiable form.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:44:00 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jan 2008 17:57:42 GMT"
}
] | 2010-07-09T00:00:00 | [
[
"Kravchenko",
"Vladislav V.",
""
]
] |
0708.2272 | Juan Maldacena | Diego M. Hofman and Juan Maldacena | Reflecting magnons | 49 pages, 11 figures | JHEP 0711:063,2007 | 10.1088/1126-6708/2007/11/063 | null | hep-th | null | We study the worldsheet reflection matrix of a string attached to a D-brane
in $AdS_5 \times S^5$. The D-brane corresponds to a maximal giant graviton and
it wraps an $S^3$ inside $S^5$. In the gauge theory, the open string is
described by a spin chain with boundaries. We study an open string with a large
SO(6) charge, which allows us to focus on one boundary at a time and to define
an asymptotic boundary reflection matrix. We consider two cases corresponding
to two possible relative orientations for the charges of the giant graviton and
the open string. Using the symmetries of the problem we compute the boundary
reflection matrix up to a phase. These matrices obey the boundary Yang Baxter
equation. A crossing equation is derived for the overall phase. We perform weak
coupling computations up to two loops and obtain results that are consistent
with integrability. Finally, we determine the phase factor at strong coupling
using classical solutions.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 19:51:10 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 21:24:09 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Hofman",
"Diego M.",
""
],
[
"Maldacena",
"Juan",
""
]
] |
0708.2273 | Ozgur Oyman | Ozgur Oyman | Opportunism in Multiuser Relay Channels: Scheduling, Routing and
Spectrum Reuse | 5 pages | IEEE International Symposium on Information Theory (ISIT), Nice,
France, June 2007 | 10.1109/ISIT.2007.4557240 | null | cs.IT math.IT | null | In order to understand the key merits of multiuser diversity techniques in
relay-assisted cellular multihop networks, this paper analyzes the spectral
efficiency of opportunistic (i.e., channel-aware) scheduling algorithms over a
fading multiuser relay channel with $K$ users in the asymptotic regime of large
(but finite) number of users. Using tools from extreme-value theory, we
characterize the limiting distribution of spectral efficiency focusing on Type
I convergence and utilize it in investigating the large system behavior of the
multiuser relay channel as a function of the number of users and physical
channel signal-to-noise ratios (SNRs). Our analysis results in very accurate
formulas in the large (but finite) $K$ regime, provides insights on the
potential performance enhancements from multihop routing and spectrum reuse
policies in the presence of multiuser diversity gains from opportunistic
scheduling and helps to identify the regimes and conditions in which
relay-assisted multiuser communication provides a clear advantage over direct
multiuser communication.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 21:44:43 GMT"
}
] | 2016-11-15T00:00:00 | [
[
"Oyman",
"Ozgur",
""
]
] |
0708.2274 | Alexander Scholz | Alexander Scholz (SUPA, St. Andrews), Jochen Eisloeffel (TLS
Tautenburg) | The first rotation periods in Praesepe | 10 pages, 3 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12333.x | null | astro-ph | null | The cluster Praesepe (age 650 Myr) is an ideal laboratory to study stellar
evolution. Specifically, it allows us to trace the long-term decline of
rotation and activity on the main-sequence. Here we present rotation periods
measured for five stars in Praesepe with masses of 0.1-0.5Ms -- the first
rotation periods for members of this cluster. Photometric periodicities were
found from two extensive monitoring campaigns, and are confirmed by multiple
independent test procedures. We attribute these variations to magnetic spots
co-rotating with the objects, thus indicating the rotation period. The five
periods, ranging from 5 to 84h, show a clear positive correlation with object
mass, a trend which has been reported previously in younger clusters. When
comparing with data for F-K stars in the coeval Hyades, we find a dramatic drop
in the periods at spectral type K8-M2 (corresponding to 0.4-0.6Ms). A
comparison with periods of VLM stars in younger clusters provides a constraint
on the spin-down timescale: We find that the exponential rotational braking
timescale is clearly longer than 200 Myr, most likely 400-800 Myr. These
results are not affected by the small sample size in the rotation periods. Both
findings, the steep drop in the period-mass relation and the long spin-down
timescale, indicate a substantial change in the angular momentum loss mechanism
for very low mass objects, possibly the breakdown of the solar-type (Skumanich)
rotational braking. While the physical origin for this behaviour is unclear, we
argue that parts of it might be explained by the disappearance of the radiative
core and the resulting breakdown of an interface-type dynamo in the VLM regime.
Rotational studies in this mass range hold great potential to probe magnetic
properties and interior structure of main-sequence stars.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:16:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Scholz",
"Alexander",
"",
"SUPA, St. Andrews"
],
[
"Eisloeffel",
"Jochen",
"",
"TLS\n Tautenburg"
]
] |
0708.2275 | Maarten Van den Nest | M. Van den Nest, W. D\"ur, H. J. Briegel | Completeness of the classical 2D Ising model and universal quantum
computation | 4 pages, 1 figure. Minor changes | Phys. Rev. Lett. 100, 110501 (2008) | 10.1103/PhysRevLett.100.110501 | null | quant-ph cond-mat.stat-mech | null | We prove that the 2D Ising model is complete in the sense that the partition
function of any classical q-state spin model (on an arbitrary graph) can be
expressed as a special instance of the partition function of a 2D Ising model
with complex inhomogeneous couplings and external fields. In the case where the
original model is an Ising or Potts-type model, we find that the corresponding
2D square lattice requires only polynomially more spins w.r.t the original one,
and we give a constructive method to map such models to the 2D Ising model. For
more general models the overhead in system size may be exponential. The results
are established by connecting classical spin models with measurement-based
quantum computation and invoking the universality of the 2D cluster states.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:27:27 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 18:12:01 GMT"
}
] | 2008-03-18T00:00:00 | [
[
"Nest",
"M. Van den",
""
],
[
"Dür",
"W.",
""
],
[
"Briegel",
"H. J.",
""
]
] |
0708.2276 | David Skinner | Lionel Mason and David Skinner | Heterotic twistor-string theory | 45 pages | Nucl.Phys.B795:105-137,2008 | 10.1016/j.nuclphysb.2007.11.010 | null | hep-th | null | We reformulate twistor-string theory as a heterotic string based on a twisted
(0,2) model. The path integral localizes on holomorphic maps, while the (0,2)
moduli naturally correspond to the states of N=4 super Yang-Mills and conformal
supergravity under the Penrose transform. We show how the standard
twistor-string formulae of scattering amplitudes as integrals over the space of
curves in supertwistor space may be obtained from our model. The corresponding
string field theory gives rise to a twistor action for N=4 conformal
supergravity coupled to super Yang-Mills. The model helps to explain how the
twistor-strings of Witten and Berkovits are related and clarifies various
aspects of each of these models.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 17:40:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mason",
"Lionel",
""
],
[
"Skinner",
"David",
""
]
] |
0708.2277 | Adrienne M. Juett | Adrienne M. Juett (Virginia), Craig L. Sarazin (Virginia), Tracy E.
Clarke (NRL), Heinz Andernach (Univ. Guanajuato), Matthias Ehle (XMM-SOC),
Yutaka Fujita (Osaka Univ.), Joshua C. Kempner (Bowdoin), Alan L. Roy
(MPIfR), Lawrence Rudnick (Minnesota) and O. Bruce Slee (ATNF) | A Chandra Observation of Abell 13: Investigating the Origin of the Radio
Relic | 11 pages, 9 figures, Accepted for Publication in the Astrophysical
Journal, higher-resolution figures can be found at
http://www.astro.virginia.edu/~amj3r/Abell13/ | null | 10.1086/523350 | null | astro-ph | null | We present results from the Chandra X-ray observation of Abell 13, a galaxy
cluster that contains an unusual noncentral radio source, also known as a radio
relic. This is the first pointed X-ray observation of Abell 13, providing a
more sensitive study of the properties of the X-ray gas. The X-ray emission
from Abell 13 is extended to the northwest of the X-ray peak and shows
substructure indicative of a recent merger event. The cluster X-ray emission is
centered on the bright galaxy H of Slee et al. 2001. We find no evidence for a
cooling flow in the cluster. A knot of excess X-ray emission is coincident with
the other bright elliptical galaxy F. This knot of emission has properties
similar to the enhanced emission associated with the large galaxies in the Coma
cluster.
With these Chandra data we are able to compare the properties of the hot
X-ray gas with those of the radio relic from VLA data, to study the interaction
of the X-ray gas with the radio emitting electrons. Our results suggest that
the radio relic is associated with cooler gas in the cluster. We suggest two
explanations for the coincidence of the cooler gas and radio source. First, the
gas may have been uplifted by the radio relic from the cluster core.
Alternatively, the relic and cool gas may have been displaced from the central
galaxy during the cluster merger event.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:13:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Juett",
"Adrienne M.",
"",
"Virginia"
],
[
"Sarazin",
"Craig L.",
"",
"Virginia"
],
[
"Clarke",
"Tracy E.",
"",
"NRL"
],
[
"Andernach",
"Heinz",
"",
"Univ. Guanajuato"
],
[
"Ehle",
"Matthias",
"",
"XMM-SOC"
],
[
"Fujita",
"Yutaka",
"",
"Osaka Univ."
],
[
"Kempner",
"Joshua C.",
"",
"Bowdoin"
],
[
"Roy",
"Alan L.",
"",
"MPIfR"
],
[
"Rudnick",
"Lawrence",
"",
"Minnesota"
],
[
"Slee",
"O. Bruce",
"",
"ATNF"
]
] |
0708.2278 | Rebecca F. Goldin | Rebecca F. Goldin | Weighted hyperprojective spaces and homotopy invariance in orbifold
cohomology | 11 pages. To appear in AMS Contemporary Mathematics (Proceedings of
the Toric Topology Conference, Osaka, Japan (May-June, 2006)) | Toric topology, 99--110, Contemp. Math., 460, Amer. Math. Soc.,
Providence, RI, 2008. | null | null | math.SG math.DG | null | We show that Chen-Ruan cohomology is a homotopy invariant in certain cases.
We introduce the notion of a T-representation homotopy, which is a stringent
form of homotopy under which Chen-Ruan cohomology is invariant. We show that
while hyperkahler quotients of the cotangent bundle to a complex vector space
by a circle S^1 (here termed weighted hyperprojective spaces) are homotopy
equivalent to weighted projective spaces, they are not S^1-representation
homotopic. Indeed, we show that their Chen-Ruan cohomology rings (over the
rationals) are distinct.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:18:21 GMT"
}
] | 2009-09-10T00:00:00 | [
[
"Goldin",
"Rebecca F.",
""
]
] |
0708.2279 | Latham Boyle | Latham A. Boyle (CITA/Princeton) and Alessandra Buonanno (Maryland) | Relating gravitational wave constraints from primordial nucleosynthesis,
pulsar timing, laser interferometers, and the CMB: implications for the early
universe | v1: 12 + 6 pages (main text + appendices), 7 figures; v2: fonts fixed
in figures | Phys.Rev.D78:043531,2008 | 10.1103/PhysRevD.78.043531 | null | astro-ph gr-qc hep-ph hep-th | null | We derive a general master equation relating the gravitational-wave
observables r and Omega_gw(f). Here r is the tensor-to-scalar ratio,
constrained by cosmic-microwave-background (CMB) experiments; and Omega_gw(f)
is the energy spectrum of primordial gravitational-waves, constrained e.g. by
pulsar-timing measurements, laser-interferometer experiments, and Big Bang
Nucleosynthesis (BBN). Differentiating the master equation yields a new
expression for the tilt d(ln Omega_gw(f))/d(ln f). The relationship between r
and Omega_gw(f) depends sensitively on the uncertain physics of the early
universe, and we show that this uncertainty may be encapsulated (in a
model-independent way) by two quantities: w_hat(f) and nt_hat(f), where
nt_hat(f) is a certain logarithmic average over nt(k) (the primordial tensor
spectral index); and w_hat(f) is a certain logarithmic average over w_tilde(a)
(the effective equation-of-state in the early universe, after horizon
re-entry). Here the effective equation-of-state parameter w_tilde(a) is a
combination of the ordinary equation-of-state parameter w(a) and the bulk
viscosity zeta(a). Thus, by comparing constraints on r and Omega_gw(f), one can
obtain (remarkably tight) constraints in the [w_hat(f), nt_hat(f)] plane. In
particular, this is the best way to constrain (or detect) the presence of a
``stiff'' energy component (with w > 1/3) in the early universe, prior to BBN.
Finally, although most of our analysis does not assume inflation, we point out
that if CMB experiments detect a non-zero value for r, then we will immediately
obtain (as a free by-product) a new upper bound w_hat < 0.55 on the
logarithmically averaged effective equation-of-state parameter during the
``primordial dark age'' between the end of inflation and the start of BBN.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 18:52:29 GMT"
},
{
"version": "v2",
"created": "Sat, 18 Aug 2007 19:45:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boyle",
"Latham A.",
"",
"CITA/Princeton"
],
[
"Buonanno",
"Alessandra",
"",
"Maryland"
]
] |
0708.2280 | Alireza Abdollahi | Alireza Abdollahi, A. Faghihi and A. Mohammadi Hassanabadi | Minimal Number of Generators and Minimum Order of a Non-Abelian Group
whose Elements Commute with Their Endomorphic Images | null | null | null | null | math.GR | null | A group in which every element commutes with its endomorphic images is called
an $E$-group. If $p$ is a prime number, a $p$-group $G$ which is an $E$-group
is called a $pE$-group. Every abelian group is obviously an $E$-group. We prove
that every 2-generator $E$-group is abelian and that all 3-generator $E$-groups
are nilpotent of class at most 2. It is also proved that every infinite
3-generator $E$-group is abelian. We conjecture that every finite 3-generator
$E$-group should be abelian. Moreover we show that the minimum order of a
non-abelian $pE$-group is $p^8$ for any odd prime number $p$ and this order is
$2^7$ for $p=2$. Some of these results are proved for a class wider than the
class of $E$-groups.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:23:25 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Abdollahi",
"Alireza",
""
],
[
"Faghihi",
"A.",
""
],
[
"Hassanabadi",
"A. Mohammadi",
""
]
] |
0708.2281 | Thomas Michael Keller | Thomas Michael Keller | A lower bound for the number of conjugacy classes of finite groups | null | null | null | null | math.GR | null | In 2000, L. H\'{e}thelyi and B. K\"{u}lshammer proved that if $p$ is a prime
number dividing the order of a finite solvable group $G$, then $G$ has at least
$2\sqrt{p-1}$ conjugacy classes. In this paper we show that if $p$ is large,
the result remains true for arbitrary finite groups.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:30:24 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Keller",
"Thomas Michael",
""
]
] |
0708.2282 | Alireza Abdollahi | Alireza Abdollahi, M. J. Ataei, A. Mohammadi Hassanabadi | Minimal blocking sets in PG(n,2) and covering groups by subgroups | null | null | null | null | math.GR math.CO | null | In this paper we prove that a set of points $B$ of PG(n,2) is a minimal
blocking set if and only if $<B>=PG(d,2)$ with $d$ odd and $B$ is a set of
$d+2$ points of $PG(d,2)$ no $d+1$ of them in the same hyperplane. As a
corollary to the latter result we show that if $G$ is a finite 2-group and $n$
is a positive integer, then $G$ admits a $\mathfrak{C}_{n+1}$-cover if and only
if $n$ is even and $G\cong (C_2)^{n}$, where by a $\mathfrak{C}_m$-cover for a
group $H$ we mean a set $\mathcal{C}$ of size $m$ of maximal subgroups of $H$
whose set-theoretic union is the whole $H$ and no proper subset of
$\mathcal{C}$ has the latter property and the intersection of the maximal
subgroups is core-free. Also for all $n<10$ we find all pairs $(m,p)$ ($m>0$ an
integer and $p$ a prime number) for which there is a blocking set $B$ of size
$n$ in $PG(m,p)$ such that $<B>=PG(m,p)$.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:36:18 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Abdollahi",
"Alireza",
""
],
[
"Ataei",
"M. J.",
""
],
[
"Hassanabadi",
"A. Mohammadi",
""
]
] |
0708.2283 | Louzari Mohamed | Mohamed louzari and L'moufadal Ben Yakoub | On quasi-Baer rings of Ore extensions | 8 pages | East-West J. of Mathematics: Vol. 8, No 2 (2006) pp. 119-127 | null | null | math.RA | null | Let $R$ be a ring and $S=R[x;\sigma,\delta]$ its Ore extension. We prove
under some conditions that $R$ is a quasi-Baer ring if and only if the Ore
extension $R[x;\sigma,\delta]$ is a quasi-Baer ring. Examples are provided to
illustrate and delimit our results.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:38:37 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Feb 2008 00:15:44 GMT"
}
] | 2009-02-24T00:00:00 | [
[
"louzari",
"Mohamed",
""
],
[
"Yakoub",
"L'moufadal Ben",
""
]
] |
0708.2284 | Thomas W. Jones | T. W. Jones | The Role of MHD in the ICM and its Interactions with AGN Outflows | 12 pages, 1 figure. To be published in the proceedings of
``Extragalactic Jets: Theory and Observation from Radio to Gamma Ray'' ASP
Conference Series; T.A. Rector and D. S. De Young, editors | null | null | null | astro-ph | null | Magnetic fields probably play a central role in the dynamics and
thermodynamics of ICMs and their interactions with AGNs, despite the fact that
the fields usually contribute relatively little pressure; i.e., the ICM is a
``high-$\beta$'' plasma. More typically, the roles of magnetic fields come
through ``microscopic'' influences on charged particle behaviors, and through
magnetic tension, which can still be significant in subsonic, high-$\beta$
flows. I briefly review these issues, while exploring the underlying question
of using the commonly-applied magnetohydrodynamics model in the ICM when
Coulomb scattering mean free paths can sometimes exceed tens of kiloparsecs.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 16:54:49 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Jones",
"T. W.",
""
]
] |
0708.2285 | Florian Gmeiner | Florian Gmeiner and Gabriele Honecker | Mapping an Island in the Landscape | 46 pages, 10 figures; v2: typos corrected, new examples and expanded
study on chiral exotics | JHEP 0709:128,2007 | 10.1088/1126-6708/2007/09/128 | CERN-PH-TH/2007-139, NIKHEF/2007-017 | hep-th hep-ph | null | We provide a complete classification and statistical analysis of all type IIA
orientifold compactifications with intersecting D6-branes on the orbifold
T^6/Z'_6. The total number of four dimensional N=1 supersymmetric models is
found to be O(10^23). After a statistical analysis of the gauge sector
properties of all possible solutions, we study three subsets of configurations
which contain the chiral matter sector of the standard model, a Pati-Salam or
SU(5) GUT model, respectively. We find O(10^15) compactifications with an MSSM
and O(10^11) models with a Pati-Salam sector. Along the way we derive an
explicit algebraic formulation for the computation of the non-chiral matter
spectrum for all Z_N orbifolds.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 14:09:05 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 16:28:59 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Gmeiner",
"Florian",
""
],
[
"Honecker",
"Gabriele",
""
]
] |
0708.2286 | Michel Gingras | S. M. A. Tabei, F. Vernay and M. J. P. Gingras | Effective Spin-1/2 Description of Transverse-Field-Induced Random Fields
in Dipolar Spin Glasses with Strong Single-Ion Anisotropy | 9 pages. 4 eps figures | Phys. Rev. B 77, 014432 (2008) | 10.1103/PhysRevB.77.014432 | null | cond-mat.dis-nn cond-mat.stat-mech | null | We present analytical and numerical evidence for the validity of an effective
S=1/2 approach to the description of random field generation in S>=1, and
especially in an S=1, dipolar spin glass models with strong uniaxial Ising
anisotropy and subject to weak external magnetic field Bx transverse to the
Ising direction. Explicitely Bx-dependent random fields are shown to naturally
emerge in the effective low-energy description of a microscopic S=1 toy model.
We discuss our results in relation to recent theoretical studies pertaining to
the topic of Bx-induced random fields in the LiHo$_x$Y$_{1-x}$F$_4$ magnetic
materials with the Ho$^{3+}$ Ising moments subject to a transverse field. We
show that the S_{eff}=1/2 approach is able to capture both the qualitative and
quantitative aspects of the physics at small Bx, giving results that agree with
those obtained using conventional second order perturbation theory.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:52:11 GMT"
}
] | 2008-01-23T00:00:00 | [
[
"Tabei",
"S. M. A.",
""
],
[
"Vernay",
"F.",
""
],
[
"Gingras",
"M. J. P.",
""
]
] |
0708.2287 | Eric Bergshoeff | Eric Bergshoeff, Jelle Hartong and Dmitri Sorokin | Q7-branes and their coupling to IIB supergravity | 31 pages, Latex file | JHEP 0712:079,2007 | 10.1088/1126-6708/2007/12/079 | null | hep-th | null | We show how, by making use of a new basis of the IIB supergravity
axion-dilaton coset, SL(2,R)/SO(2), 7-branes that belong to different conjugacy
classes of the duality group SL(2,R) naturally couple to IIB supergravity with
appropriate source terms characterized by an SL(2,R) charge matrix Q. The
conjugacy classes are determined by the value of the determinant of Q. The
(p,q) 7-branes are the branes in the conjugacy class detQ = 0. The 7-branes in
the conjugacy class detQ > 0 are labelled by three numbers (p,q,r) which
parameterize the matrix Q and will be called Q7-branes. We construct the full
bosonic Wess--Zumino term for the Q7-branes. In order to realize a gauge
invariant coupling of the Q7-brane to the gauge fields of IIB supergravity it
is necessary to introduce an SL(2,R) doublet of two distinct Born--Infeld
fields on the Q7-brane world-volume.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 15:21:47 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Bergshoeff",
"Eric",
""
],
[
"Hartong",
"Jelle",
""
],
[
"Sorokin",
"Dmitri",
""
]
] |
0708.2288 | Robert Finkelstein j | Robert J. Finkelstein | Scalar Trefoils | 16 pages, LaTex file | null | null | UCLA/07/TEP/18 | hep-th | null | The knot model is extended by assuming that the trefoils are realized as
either chiral fermions or as scalar bosons. There are then four scalar trefoils
with electric charges (0, -1,2/3,-1/3) that may be classified in the same way
as the chiral fermions: as two isotopic doublets where the two doublets have
different hypercharge and the two members of the doublets have different t_3.
Only the neutral scalar plays the role of the standard Higgs in fixing the mass
ratios of the vector bosons, wile the charged scalars, in addition to having
the usual electromagnetic interactions of scalar particles, fix the mass
spectrum of the fermions. The extended model would suggest a search for the
charged scalars.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 20:54:05 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Oct 2007 18:21:30 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Finkelstein",
"Robert J.",
""
]
] |
0708.2289 | Brian Kirby | B. J. Kirby, J. A. Borchers, X. Liu, Y.J. Cho, M. Dobrowolska and J.
K. Furdyna | Definitive Evidence of Interlayer Coupling Between (Ga,Mn)As Layers
Separated by a Nonmagnetic Spacer | Submitted to Physical Review B | null | 10.1103/PhysRevB.76.205316 | null | cond-mat.mtrl-sci | null | We have used polarized neutron reflectometry to study the structural and
magnetic properties of the individual layers in a series of
(Al,Be,Ga)As/(Ga,Mn)As/GaAs/(Ga,Mn)As multilayer samples. Structurally, we
observe that the samples are virtually identical except for the GaAs spacer
thickness (which varies from 3-12 nm), and confirm that the spacers contain
little or no Mn. Magnetically, we observe that for the sample with the thickest
spacer layer, modulation doping by the(Al,Be,Ga)As results in (Ga,Mn)As layers
with very different temperature dependent magnetizations. However, as the
spacer layer thickness is reduced, the temperature dependent magnetizations of
the top an bottom (Ga,Mn)As layers become progressively more similar - a trend
we find to be independent of the crystallographic direction along which spins
are magnetized. These results definitively show that (Ga,Mn)As layers can
couple across a non-magnetic spacer, and that such coupling depends on spacer
thickness.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 21:09:40 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Sep 2007 13:50:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kirby",
"B. J.",
""
],
[
"Borchers",
"J. A.",
""
],
[
"Liu",
"X.",
""
],
[
"Cho",
"Y. J.",
""
],
[
"Dobrowolska",
"M.",
""
],
[
"Furdyna",
"J. K.",
""
]
] |
0708.2290 | Lawrence Brown | Lawrence G. Brown | MASA's and certain type I closed faces of C*-algebras | This paper will appear in a volume of Contemporary Mathematics
dedicated to the memory of George W. Mackey | null | null | null | math.OA | null | A result of Akemann, Anderson, and Pedersen states that if a sequence of pure
states of a C*-algebra A approaches infinity in a certain sense, then there is
a MASA B such that each of the states has the unique extension property with
respect to B. We generalize this in two ways: We prove that B can be required
to contain an approximate identity of A, and we show that the discrete space
which underlies the result cited can be replaced with a totally disconnected
space.
We consider two special kinds of type I closed faces, both related to the
above, atomic closed faces and closed faces with nearly closed extreme
boundary. One specific question is whether an atomic closed face always has an
"isolated point". We give a counterexample for this and also show that the
answer is yes if the the atomic face has nearly closed extreme boundary.
We prove a complement to Glimm's theorem on type I C*-algebras which arises
from the theory of type I closed faces. One of our examples is a type I closed
face which is isomorphic to a closed face of every non-type I separable
C*-algebra and which is not isomorphic to a closed face of any type I
C*-algebra.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 21:25:52 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Brown",
"Lawrence G.",
""
]
] |
0708.2291 | Markus Boettcher | M. Boettcher, et al | The WEBT Campaign on the Blazar 3C279 in 2006 | Accepted for publication in ApJ | null | 10.1086/522583 | null | astro-ph | null | The quasar 3C279 was the target of an extensive multiwavelength monitoring
campaign from January through April 2006, including an optical-IR-radio
monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration.
In this paper we focus on the results of the WEBT campaign. The source
exhibited substantial variability of optical flux and spectral shape, with a
characteristic time scale of a few days. The variability patterns throughout
the optical BVRI bands were very closely correlated with each other. In
intriguing contrast to other (in particular, BL Lac type) blazars, we find a
lag of shorter- behind longer-wavelength variability throughout the RVB ranges,
with a time delay increasing with increasing frequency. Spectral hardening
during flares appears delayed with respect to a rising optical flux. This, in
combination with the very steep IR-optical continuum spectral index of ~ 1.5 -
2.0, may indicate a highly oblique magnetic field configuration near the base
of the jet. An alternative explanation through a slow (time scale of several
days) acceleration mechanism would require an unusually low magnetic field of <
0.2 G, about an order of magnitude lower than inferred from previous analyses
of simultaneous SEDs of 3C279 and other FSRQs with similar properties.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 22:04:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boettcher",
"M.",
""
]
] |
0708.2292 | Abel Klein | Abel Klein | Multiscale Analysis and Localization of Random Operators | null | null | null | null | math-ph math.MP | null | A discussion of the method of multiscale analysis in the study of
localization of random operators based on lectures given at \emph{Random
Schr\"odinger operators: methods, results, and perspectives}, \'Etats de la
recherche, Universit\'e Paris 13, June 2002
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 22:07:50 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Klein",
"Abel",
""
]
] |
0708.2293 | Abel Klein | Fran\c{c}ois Germinet and Abel Klein | Localization for a continuum Cantor-Anderson Hamiltonian | null | null | null | null | math-ph math.MP | null | We prove localization at the bottom of the spectrum for a random
Schr\"odinger operator in the continuum with a single-site potential
probability distribution supported by a Cantor set of zero Lebesgue measure.
This distribution is too singular to be treated by the usual methods. In
particular, an "a priori" Wegner estimate is not available. To prove the result
we perform a multiscale analysis following the work of Bourgain and Kenig for
the Bernoulli-Anderson Hamiltonian, and obtain the required Wegner estimate
scale by scale. To do so, we generalize their argument based on Sperner's Lemma
by resorting to the LYM inequality for multisets, and combine it with the
concept of scale dependent equivalent classes of configurations introduced by
Germinet, Hislop and Klein for the study of Poisson Hamiltonians.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 22:19:16 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Germinet",
"François",
""
],
[
"Klein",
"Abel",
""
]
] |
0708.2294 | Maria A. Avino-Diaz | Maria A. Avino-Diaz | A probabilistic regulatory network for the human immune system | 9 pages | null | null | null | q-bio.CB q-bio.BM | null | In this paper we made a review of some papers about probabilistic regulatory
networks (PRN), in particular we introduce our concept of homomorphisms of PRN
with an example of projection of a regulatory network to a smaller one. We
apply the model PRN (or Probabilistic Boolean Network) to the immune system,
the PRN works with two functions. The model called ""The B/T-cells
interaction"" is Boolean, so we are really working with a Probabilistic Boolean
Network. Using Markov Chains we determine the state of equilibrium of the
immune response.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 16:19:42 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Avino-Diaz",
"Maria A.",
""
]
] |
0708.2295 | Kiran S. Kedlaya | Kiran S. Kedlaya | Product-free subsets of groups, then and now | 9 pages; from conference "Communicating Mathematics" in honor of Joe
Gallian (Duluth, 2007); v2: refereed version, very minor revisions | null | null | null | math.GR math.CO | null | A subset of a group is product-free if it does not contain elements a, b, c
such that ab = c. We review progress on the problem of determining the size of
the largest product-free subset of an arbitrary finite group, including a lower
bound due to the author, and a recent upper bound due to Gowers. The bound of
Gowers is more general; it allows three different sets A, B, C such that one
cannot solve ab = c with a in A, b in B, c in C. We exhibit a refinement of the
lower bound construction which shows that for this broader question, the bound
of Gowers is essentially optimal.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 23:17:02 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Nov 2007 22:12:48 GMT"
}
] | 2007-11-08T00:00:00 | [
[
"Kedlaya",
"Kiran S.",
""
]
] |
0708.2296 | Simone Migliari | S. Migliari (CASS/UCSD), J. C. A. Miller-Jones (Amsterdam), R. P.
Fender (Southampton), J. Homan (MIT), T. Di Salvo (Palermo), R. E. Rothschild
(CASS/UCSD), M. P. Rupen (NRAO), J. A. Tomsick (SSL/UCB), R. Wijnands
(Amsterdam), M. van der Klis (Amsterdam) | Linking Jet Emission, X-ray States and Hard X-ray Tails in the Neutron
Star X-ray Binary GX 17+2 | Accepted by ApJ | null | 10.1086/522516 | null | astro-ph | null | We present the results from simultaneous radio (Very Large Array) and X-ray
(Rossi-X-ray Timing Explorer) observations of the Z-type neutron star X-ray
binary GX~17+2. The aim is to assess the coupling between X-ray and radio
properties throughout its three rapidly variable X-ray states and during the
time-resolved transitions. These observations allow us, for the first time, to
investigate quantitatively the possible relations between the radio emission
and the presence of the hard X-ray tails and the X-ray state of the source. The
observations show: 1) a coupling between the radio jet emission and the X-ray
state of the source, i.e. the position in the X-ray hardness-intensity diagram
(HID); 2) a coupling between the presence of a hard X-ray tail and the position
in the HID, qualitatively similar to that found for the radio emission; 3) an
indication for a quantitative positive correlation between the radio flux
density and the X-ray flux in the hard-tail power law component; 4) evidence
for the formation of a radio jet associated with the Flaring Branch-to-Normal
Branch X-ray state transition; 5) that the radio flux density of the
newly-formed jet stabilizes when also the normal-branch oscillation (NBO) in
the X-ray power spectrum stabilizes its characteristic frequency, suggesting a
possible relation between X-ray variability associated to the NBO and the jet
formation. We discuss our results in the context of jet models.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 23:22:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Migliari",
"S.",
"",
"CASS/UCSD"
],
[
"Miller-Jones",
"J. C. A.",
"",
"Amsterdam"
],
[
"Fender",
"R. P.",
"",
"Southampton"
],
[
"Homan",
"J.",
"",
"MIT"
],
[
"Di Salvo",
"T.",
"",
"Palermo"
],
[
"Rothschild",
"R. E.",
"",
"CASS/UCSD"
],
[
"Rupen",
"M. P.",
"",
"NRAO"
],
[
"Tomsick",
"J. A.",
"",
"SSL/UCB"
],
[
"Wijnands",
"R.",
"",
"Amsterdam"
],
[
"van der Klis",
"M.",
"",
"Amsterdam"
]
] |
0708.2297 | Gerald A. Miller | Gerald A. Miller | Densities, Parton Distributions, and Measuring the Non-Spherical Shape
of the Nucleon | 7 pages, two figures | Phys.Rev.C76:065209,2007 | 10.1103/PhysRevC.76.065209 | NT@UW-07-10 | nucl-th hep-ex hep-ph nucl-ex | null | Spin-dependent quark densities, matrix elements of specific density operators
in proton states of definite spin-polarization, indicate that the nucleon may
harbor an infinite variety of non-spherical shapes. We show that these matrix
elements are closely related to specific transverse momentum dependent parton
distributions accessible in the angular dependence of the semi-inclusive
processes electron plus proton goes to electron plus pion plus anything, and
the Drell-Yan reaction proton plus proton goes to a lepton anti-lepton pair
plus anything. New measurements or analyses would allow the direct exhibition
of the non-spherical nature of the proton.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 23:35:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Miller",
"Gerald A.",
""
]
] |
0708.2298 | Federico Zertuche | David Romero and Federico Zertuche | The Number of Different Binary Functions Generated by NK-Kauffman
Networks and the Emergence of Genetic Robustness | 4 figures 18 pages | Published in: Journal of Mathematical Physics Vol.48 (2007) 083506 | 10.1063/1.2768747 | null | nlin.AO nlin.CD | null | We determine the average number $ \vartheta (N, K) $, of \textit{NK}-Kauffman
networks that give rise to the same binary function. We show that, for $ N \gg
1 $, there exists a connectivity critical value $ K_c $ such that $
\vartheta(N,K) \approx e^{\phi N} $ ($ \phi > 0 $) for $ K < K_c $ and
$\vartheta(N,K) \approx 1 $ for $ K > K_c $. We find that $ K_c $ is not a
constant, but scales very slowly with $ N $, as $ K_c \approx \log_2 \log_2 (2N
/ \ln 2) $. The problem of genetic robustness emerges as a statistical property
of the ensemble of \textit{NK}-Kauffman networks and impose tight constraints
in the average number of epistatic interactions that the genotype-phenotype map
can have.
| [
{
"version": "v1",
"created": "Thu, 16 Aug 2007 23:50:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Romero",
"David",
""
],
[
"Zertuche",
"Federico",
""
]
] |
0708.2299 | Tristan Roy | Tristan Roy | Global well-posedness for the radial defocusing cubic wave equation on
$\mathbb{R}^{3}$ and for rough data | 23 pages. Update | null | null | null | math.AP math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We prove global well-posedness for the $3D$ radial defocusing cubic wave
equation with data in $H^{s} \times H^{s-1}$, $1>s>{7/10}$.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 00:02:57 GMT"
},
{
"version": "v2",
"created": "Sun, 19 Aug 2007 22:27:05 GMT"
},
{
"version": "v3",
"created": "Sun, 10 Feb 2008 04:10:39 GMT"
},
{
"version": "v4",
"created": "Fri, 16 Jun 2017 13:23:49 GMT"
},
{
"version": "v5",
"created": "Tue, 27 Jun 2017 15:40:40 GMT"
}
] | 2017-06-28T00:00:00 | [
[
"Roy",
"Tristan",
""
]
] |
0708.2300 | Yuhai Qin | Yuhai Qin, Trevor A. Tyson, Klaus Pranzas and Helmut Eckerlebe | Observation of Ferromagnetic Clusters in Bi0.125Ca0.875MnO3 | 14 pages, 6 figues | null | 10.1088/0953-8984/20/19/195209 | null | cond-mat.mtrl-sci | null | The electron doped manganite system, Bi0.125Ca0.875MnO3, exhibits large bulk
magnetization of unknown origin. To select amongst possible magnetic ordering
models, we have conducted temperature and magnetic field dependent small-angle
neutron scattering measurements. Nontrivial spin structure has been revealed.
Ferromagnetic spin clusters form in the antiferromagnetic background when
temperature is decreased to Tc~108K. With a further reduction in temperature or
the application of external magnetic field, the clusters begin to form in
larger numbers, which gives an overall enhancement of magnetization below Tc.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 00:34:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Qin",
"Yuhai",
""
],
[
"Tyson",
"Trevor A.",
""
],
[
"Pranzas",
"Klaus",
""
],
[
"Eckerlebe",
"Helmut",
""
]
] |
0708.2301 | Guanghan Cao | C. Wang, H. J. Zhang, P. M. He and G. H. Cao | Ti-rich and Cu-poor grain-boundary layers of CaCu$_3$Ti$_4$O$_{12}$
detected by x-ray photoelectron spectroscopy | 8 pages, 3 figures | APPLIED PHYSICS LETTERS 91, 052910 (2007) | 10.1063/1.2768006 | null | cond-mat.mtrl-sci cond-mat.other | null | Cleaved and polished surfaces of CaCu$_3$Ti$_4$O$_{12}$ ceramics have been
investigated by x-ray photoelectron spectroscopy (XPS) and energy dispersive
x-ray spectroscopy (EDX), respectively. While EDX technique shows the identical
CaCu$_3$Ti$_4$O$_{12}$ stoichiometry for the two surfaces, XPS indicates that
the cleaved surface with grain-boundary layers is remarkably Ti-rich and
Cu-poor. The core-level spectrum of Cu 2$p$ unambiguously shows the existence
of monovalent copper only for the cleaved surface. Possible grain-boundary
structure and its formation are discussed.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 00:44:10 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Wang",
"C.",
""
],
[
"Zhang",
"H. J.",
""
],
[
"He",
"P. M.",
""
],
[
"Cao",
"G. H.",
""
]
] |
0708.2302 | Mladen Pavicic | Mladen Pavicic | Nondestructive interaction-free atom-photon controlled-NOT gate | 20 pages, 5 figures, Web page: http://m3k.grad.hr/pavicic | Physical Review A, 75, 032342 (2007); Virtual Journal of Quantum
Information, Volume 7, Issue 4 | 10.1103/PhysRevA.75.032342 | null | quant-ph | null | We present a probabilistic (ideally 50%) nondestructive interaction-free
atom-photon controlled-NOT gate, where nondestructive means that all four
outgoing target photon modes of the gate are available and feed-forwardable.
Individual atoms are controlled by a stimulated Raman adiabatic passage
transition and photons by a ring resonator with two outgoing ports. Realistic
estimates we obtain for ions confined in a Paul trap around which the resonator
is mounted show that a strong atom-photon coupling can be achieved. It is also
shown how the resonator can be used for controlling superposition of atom
states.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 00:51:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pavicic",
"Mladen",
""
]
] |
0708.2303 | W Saba | Walid S. Saba | Compositional Semantics Grounded in Commonsense Metaphysics | null | null | null | null | cs.AI cs.CL | null | We argue for a compositional semantics grounded in a strongly typed ontology
that reflects our commonsense view of the world and the way we talk about it in
ordinary language. Assuming the existence of such a structure, we show that the
semantics of various natural language phenomena may become nearly trivial.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 01:15:11 GMT"
},
{
"version": "v2",
"created": "Fri, 31 Aug 2007 17:48:14 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Saba",
"Walid S.",
""
]
] |
0708.2304 | Melvyn B. Nathanson | Melvyn B. Nathanson | Inverse problems for linear forms over finite sets of integers | 12 pages; minor corrections | Journal of the Ramanujan Mathematical Society 23 (2008), 151--165 | null | null | math.NT math.CO | null | Let f(x_1,x_2,...,x_m) = u_1x_1+u_2 x_2+... + u_mx_m be a linear form with
positive integer coefficients, and let N_f(k) = min{|f(A)| : A \subseteq Z and
|A|=k}. A minimizing k-set for f is a set A such that |A|=k and |f(A)| =
N_f(k). A finite sequence (u_1, u_2,...,u_m) of positive integers is called
complete if {\sum_{j\in J} u_j : J \subseteq {1,2,..,m}} = {0,1,2,..., U},
where $U = \sum_{j=1}^m u_j.$ It is proved that if f is an m-ary linear form
whose coefficient sequence (u_1,...,u_m) is complete, then N_f(k) = Uk-U+1 and
the minimizing k-sets are precisely the arithmetic progressions of length k.
Other extremal results on linear forms over finite sets of integers are
obtained.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 01:15:26 GMT"
},
{
"version": "v2",
"created": "Tue, 21 Aug 2007 14:57:58 GMT"
}
] | 2021-01-06T00:00:00 | [
[
"Nathanson",
"Melvyn B.",
""
]
] |
0708.2305 | Yanyang Zhang | Yan-Yang Zhang, Jiang-Ping Hu, X. C. Xie and W. M. Liu | Abnormal Electronic Transport in Disordered Graphene Nanoribbon | 4 pages, 5 figures | null | null | null | cond-mat.mes-hall cond-mat.dis-nn | null | We investigate the conductivity $\sigma$ of graphene nanoribbons with zigzag
edges as a function of Fermi energy $E_F$ in the presence of the impurities
with different potential range. The dependence of $\sigma(E_F)$ displays four
different types of behavior, classified to different regimes of length scales
decided by the impurity potential range and its density. Particularly, low
density of long range impurities results in an extremely low conductance
compared to the ballistic value, a linear dependence of $\sigma(E_F)$ and a
wide dip near the Dirac point, due to the special properties of long range
potential and edge states. These behaviors agree well with the results from a
recent experiment by Miao \emph{et al.} (to appear in Science).
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 02:24:05 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Zhang",
"Yan-Yang",
""
],
[
"Hu",
"Jiang-Ping",
""
],
[
"Xie",
"X. C.",
""
],
[
"Liu",
"W. M.",
""
]
] |
0708.2306 | Daniel Wegner | D. Wegner, A. Bauer and G. Kaindl | Effects of impurities on Tamm-like lanthanide-metal surface states | 5 pages, 4 figures, accepted as Brief Report for Physical Review B | null | 10.1103/PhysRevB.76.113410 | null | cond-mat.mtrl-sci | null | The effects of isolated residual-gas adsorbates on the local electronic
structure of the Dy(0001) surface were spatially mapped by scanning tunneling
microscopy and spectroscopy at 12 K. Less than 15 A away from an adsorbate, a
strong reduction of the intensity and a significant increase of the width of
the majority component of the surface state due to impurity scattering were
observed, with essentially no change of the minority component; this reflects a
high lateral localization of the Tamm-like surface state. Furthermore, an
adsorbate-induced state was found that behaves metastable.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 01:36:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wegner",
"D.",
""
],
[
"Bauer",
"A.",
""
],
[
"Kaindl",
"G.",
""
]
] |
0708.2307 | Damien Roy | Damien Roy | Small value estimates for the additive group | 35 pages | International J. Number Theory, vol. 6 (2010), 919-956 | null | null | math.NT | null | We generalize Gel'fond's criterion of algebraic independence to the context
of a sequence of polynomials whose first derivatives take small values on large
subsets of a fixed subgroup of the additive group of complex numbers, instead
of just one point. We also provide one extension dealing with a subgroup of the
multiplicative group of non-zero complex numbers.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 01:49:54 GMT"
}
] | 2013-01-07T00:00:00 | [
[
"Roy",
"Damien",
""
]
] |
0708.2308 | Takahiro Harada | Tomomi Yokogawa and Takahiro Harada | Intermittent dynamics and 1/f^beta noise in single cardiac muscle cells | 5 pages, 5 figures | null | null | null | q-bio.CB | null | Fluctuations in the spontaneous beating activity of isolated cardiac cells
were studied over a timescale of six decades. The beat dynamics of single
cardiac cells were heterogeneous and intermittent. The interbeat intervals
(IBIs) were power-law distributed in a long-time regime. Furthermore, for long
timescales up to the experimental window, the autocorrelation of IBIs exhibits
a scaling behavior of 1/f^beta-noise type. These observations suggest that
1/f^beta noise is an intrinsic characteristic of spontaneous activity of single
cardiac cells.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 02:26:23 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Yokogawa",
"Tomomi",
""
],
[
"Harada",
"Takahiro",
""
]
] |
0708.2309 | Dmitri Krioukov | Dmitri Krioukov, kc claffy, Kevin Fall, Arthur Brady | On Compact Routing for the Internet | This is a significantly revised, journal version of cs/0508021 | ACM SIGCOMM Computer Communication Review (CCR), v.37, n.3,
p.41-52, 2007 | 10.1145/1273445.1273450 | null | cs.NI | null | While there exist compact routing schemes designed for grids, trees, and
Internet-like topologies that offer routing tables of sizes that scale
logarithmically with the network size, we demonstrate in this paper that in
view of recent results in compact routing research, such logarithmic scaling on
Internet-like topologies is fundamentally impossible in the presence of
topology dynamics or topology-independent (flat) addressing. We use analytic
arguments to show that the number of routing control messages per topology
change cannot scale better than linearly on Internet-like topologies. We also
employ simulations to confirm that logarithmic routing table size scaling gets
broken by topology-independent addressing, a cornerstone of popular
locator-identifier split proposals aiming at improving routing scaling in the
presence of network topology dynamics or host mobility. These pessimistic
findings lead us to the conclusion that a fundamental re-examination of
assumptions behind routing models and abstractions is needed in order to find a
routing architecture that would be able to scale ``indefinitely.''
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 02:37:20 GMT"
}
] | 2008-04-16T00:00:00 | [
[
"Krioukov",
"Dmitri",
""
],
[
"claffy",
"kc",
""
],
[
"Fall",
"Kevin",
""
],
[
"Brady",
"Arthur",
""
]
] |
0708.2310 | Lav Varshney | Lav R. Varshney and Vivek K. Goyal | Benefiting from Disorder: Source Coding for Unordered Data | 35 pages | null | null | null | cs.IT math.IT | null | The order of letters is not always relevant in a communication task. This
paper discusses the implications of order irrelevance on source coding,
presenting results in several major branches of source coding theory: lossless
coding, universal lossless coding, rate-distortion, high-rate quantization, and
universal lossy coding. The main conclusions demonstrate that there is a
significant rate savings when order is irrelevant. In particular, lossless
coding of n letters from a finite alphabet requires Theta(log n) bits and
universal lossless coding requires n + o(n) bits for many countable alphabet
sources. However, there are no universal schemes that can drive a strong
redundancy measure to zero. Results for lossy coding include distribution-free
expressions for the rate savings from order irrelevance in various high-rate
quantization schemes. Rate-distortion bounds are given, and it is shown that
the analogue of the Shannon lower bound is loose at all finite rates.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 03:13:26 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Varshney",
"Lav R.",
""
],
[
"Goyal",
"Vivek K.",
""
]
] |
0708.2311 | Yushu Song | Yushu Song | Phase Transition Dynamics and Its Alpha' Corrections | 16 pages, no figure;Added references and discussions; | Phys.Rev.D76:106014,2007 | 10.1103/PhysRevD.76.106014 | USTC-ICTS-07-18 | hep-th hep-ph | null | We study the dynamics of the first order phase transition in the holographic
hard wall model, namely, Polchinski-Strassler's model and come to the
conclusion that the phase transition is incomplete in large N limit with the
natural boundary condition. We also consider the string length corrections to
both hard wall model and Witten's model, and find that the interesting
transition configuration is preserved under the alpha' corrections.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 04:31:10 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Oct 2007 15:47:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Song",
"Yushu",
""
]
] |
0708.2312 | Hisayuki Hara | Hisayuki Hara, Akimichi Takemura and Ruriko Yoshida | Markov bases for two-way subtable sum problems | 23 pages | Journal of Pure and Applied Algebra, Vol.213, Issue 8, 1507-1521.
(2009) | 10.1016/j.jpaa.2008.11.019 | null | math.CO math.AC | null | It has been well-known that for two-way contingency tables with fixed row
sums and column sums the set of square-free moves of degree two forms a Markov
basis. However when we impose an additional constraint that the sum of a
subtable is also fixed, then these moves do not necessarily form a Markov
basis. Thus, in this paper, we show a necessary and sufficient condition on a
subtable so that the set of square-free moves of degree two forms a Markov
basis.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 04:42:15 GMT"
}
] | 2009-04-27T00:00:00 | [
[
"Hara",
"Hisayuki",
""
],
[
"Takemura",
"Akimichi",
""
],
[
"Yoshida",
"Ruriko",
""
]
] |
0708.2313 | Igor Nekrasov | I. A. Nekrasov, E. E. Kokorina, E. Z. Kuchinskii, Z. V. Pchelkina, M.
V. Sadovskii | Comparative study of electron and hole doped High-Tc compounds in
pseudogap regime: LDA+DMFT+Sk approach | 4 pages, 4 figures, submitted to SNS2007 proceedings | Journal of Physics and Chemistry of Solids 69, 3269 (2008) | 10.1016/j.jpcs.2008.06.120 | null | cond-mat.str-el cond-mat.supr-con | null | Pseudogap regime for the prototype high-Tc compounds hole doped
Bi2Sr2CaCu2O8-x (Bi2212) and electron doped Nd2-xCexCuO4 (NCCO) is described by
means of novel generalized LDA+DMFT+Sk approach. Here conventional dynamical
mean-field theory (DMFT) equations are supplied with additional (momentum
dependent) self-energy Sk. In the present case Sk describes non-local dynamical
correlations induced by short-ranged collective Heisenberg-like
antiferromagnetic spin fluctuations. Material specific model parameters of two
neighboring CuO2 layers of Bi2212 and single CuO2 layer of NCCO were obtained
within local density approximation (LDA) and constrained LDA method. We show
that Fermi surface in presence of the pseudogap fluctuations have perfectly
visible "hot-spots" for NCCO while in Bi2212 there is just rather broad region
with strong antiferromagnetic scattering. Results obtained are in good
agreement with recent ARPES and optical experiments.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 04:39:54 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 09:53:36 GMT"
}
] | 2009-05-06T00:00:00 | [
[
"Nekrasov",
"I. A.",
""
],
[
"Kokorina",
"E. E.",
""
],
[
"Kuchinskii",
"E. Z.",
""
],
[
"Pchelkina",
"Z. V.",
""
],
[
"Sadovskii",
"M. V.",
""
]
] |
0708.2314 | Ryan Cooke | Ryan Cooke (1), Zdenka Kuncic (1), Rob Sharp (2) and Joss
Bland-Hawthorn (2) ((1) University of Sydney, Australia, (2) Anglo-Australian
Observatory, Sydney, Australia) | Spectacular Trailing Streamers near LMC X-1: The First Evidence of a
Jet? | Accepted for publication in The Astrophysical Journal Letters. Hi-res
figure available at
http://www.physics.usyd.edu.au/~kuncic/LMCX1/Cooke_etal_fig1.eps.gz | null | 10.1086/522517 | null | astro-ph | null | We report VIMOS integral field spectroscopy of the N159F nebula surrounding
LMC X-1. Our observations reveal a rich, extended system of emission line
filaments lining the boundary of a large conical cavity identified in Spitzer
mid-IR imaging. We find that X-ray photoionization cannot be solely responsible
for the observed ionization structure of N159F. We propose that the extended
filamentary emission is produced primarily by ionization from a shock driven by
a presently unobserved jet from LMC X-1. We infer a shock velocity of v_s ~ 90
km/s and conclude that the jet responsible for the bow shock is presently
undetected because it has switched off, rather than because it has a low
surface brightness. This interpretation is consistent with the present soft
X-ray spectral state of LMC X-1 and suggests the jet is intermittent.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 05:26:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cooke",
"Ryan",
""
],
[
"Kuncic",
"Zdenka",
""
],
[
"Sharp",
"Rob",
""
],
[
"Bland-Hawthorn",
"Joss",
""
]
] |
0708.2315 | Pavel Kolesnikov | Pavel Kolesnikov | Conformal representations of Leibniz algebras | misc. note to arXiv:math/0611501 | (Russian) Sib. Mat. Zh. 49 (2008), no. 3, 540-547 | null | null | math.RA math.QA | null | In this note we present a more detailed and explicit exposition of the
definition of a conformal representation of a Leibniz algebra. Recall
(arXiv:math/0611501v3) that Leibniz algebras are exactly Lie dialgebras. The
idea is based on the general fact that every dialgebra that belongs to a
variety $\Var $ can be embedded into a conformal algebra of the same variety.
In particular, we prove that an arbitrary (finite dimensional) Leibniz algebra
has a (finite) faithful conformal representation. As a corollary, we deduce the
analogue of the PBW-theorem for Leibniz algebras.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 05:06:27 GMT"
}
] | 2012-08-14T00:00:00 | [
[
"Kolesnikov",
"Pavel",
""
]
] |
0708.2316 | Yuichi Yamada | Yuichi Yamada | Generalized rational blow-down, torus knots, and Euclidean algorithm | 10 pages, 8 figures | null | null | null | math.GT | null | We construct a Kirby diagram of the rational homology ball used in
"generalized rational blow-down" developed by Jongil Park. The diagram consists
of a dotted circle and a torus knot. The link is simpler, but the parameters
are a little complicate. Euclidean Algorithm is used three times in the
construction and the proof.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 05:11:37 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Yamada",
"Yuichi",
""
]
] |
0708.2317 | Alexis Diaz-Torres | A. Diaz-Torres, L. R. Gasques and M. Wiescher | Effects of nuclear molecular configurations on the astrophysical
S-factor for $^{16}$O + $^{16}$O | In press in Physics Letters B | Phys.Lett.B652:255-258,2007 | 10.1016/j.physletb.2007.06.077 | null | nucl-th | null | The impact of nuclear molecular configurations on the astrophysical S-factor
for $^{16}$O + $^{16}$O is investigated within the realistic two-center shell
model based on Woods-Saxon potentials. These molecular effects refer to the
formation of a neck between the interacting nuclei and the radial dependent
collective mass parameter. It is demonstrated that the former is crucial to
explain the current experimental data with high accuracy and without any free
parameter, whilst in addition the latter predicts a pronounced maximum in the
S-factor. In contrast to very recent results by Jiang et al., the S-factor does
not decline towards extremely low values as energy decreases.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 05:43:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Diaz-Torres",
"A.",
""
],
[
"Gasques",
"L. R.",
""
],
[
"Wiescher",
"M.",
""
]
] |
0708.2318 | Woo Seok Choi | W. S. Choi, D. G. Kim, S. S. A. Seo, S. J. Moon, D. Lee, J. H. Lee, H.
S. Lee, D.-Y. Cho, Y. S. Lee, P. Murugavel, Jaejun Yu and T. W. Noh | Electronic structures of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin
films | null | Phys. Rev. B 77, 045137 (2008) | 10.1103/PhysRevB.77.045137 | null | cond-mat.str-el | null | We investigated the electronic structure of multiferroic hexagonal RMnO3 (R =
Gd, Tb, Dy, and Ho) thin films using both optical spectroscopy and
first-principles calculations. Using artificially stabilized hexagonal RMnO3,
we extended the optical spectroscopic studies on the hexagonal multiferroic
manganite system. We observed two optical transitions located near 1.7 eV and
2.3 eV, in addition to the predominant absorption above 5 eV. With the help of
first-principles calculations, we attribute the low-lying optical absorption
peaks to inter-site transitions from the oxygen states hybridized strongly with
different Mn orbital symmetries to the Mn 3d3z2-r2 state. As the ionic radius
of the rare earth ion increased, the lowest peak showed a systematic increase
in its peak position. We explained this systematic change in terms of a
flattening of the MnO5 triangular bipyramid.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 05:47:30 GMT"
}
] | 2010-05-17T00:00:00 | [
[
"Choi",
"W. S.",
""
],
[
"Kim",
"D. G.",
""
],
[
"Seo",
"S. S. A.",
""
],
[
"Moon",
"S. J.",
""
],
[
"Lee",
"D.",
""
],
[
"Lee",
"J. H.",
""
],
[
"Lee",
"H. S.",
""
],
[
"Cho",
"D. -Y.",
""
],
[
"Lee",
"Y. S.",
""
],
[
"Murugavel",
"P.",
""
],
[
"Yu",
"Jaejun",
""
],
[
"Noh",
"T. W.",
""
]
] |
0708.2319 | Marcus Hutter | Marcus Hutter and Andrej Muchnik | On Semimeasures Predicting Martin-Loef Random Sequences | 21 LaTeX pages | Theoretical Computer Science, 382 (2007) 247-261 | null | null | cs.IT cs.LG math.IT math.PR | null | Solomonoff's central result on induction is that the posterior of a universal
semimeasure M converges rapidly and with probability 1 to the true sequence
generating posterior mu, if the latter is computable. Hence, M is eligible as a
universal sequence predictor in case of unknown mu. Despite some nearby results
and proofs in the literature, the stronger result of convergence for all
(Martin-Loef) random sequences remained open. Such a convergence result would
be particularly interesting and natural, since randomness can be defined in
terms of M itself. We show that there are universal semimeasures M which do not
converge for all random sequences, i.e. we give a partial negative answer to
the open problem. We also provide a positive answer for some non-universal
semimeasures. We define the incomputable measure D as a mixture over all
computable measures and the enumerable semimeasure W as a mixture over all
enumerable nearly-measures. We show that W converges to D and D to mu on all
random sequences. The Hellinger distance measuring closeness of two
distributions plays a central role.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 06:39:11 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Hutter",
"Marcus",
""
],
[
"Muchnik",
"Andrej",
""
]
] |
0708.2320 | Rozanova Olga | Sergio Albeverio, Olga Rozanova | The non-viscous Burgers equation associated with random positions in
coordinate space: a threshold for blow up behaviour | 12 pages, submitted Minor corrections to the text and algebra, added
references | Mathematical Models and Methods in Applied Sciences Vol. 19, No. 5
(2009) 1-19 | null | null | math.AP math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It is well known that the solutions to the non-viscous Burgers equation
develop a gradient catastrophe at a critical time provided the initial data
have a negative derivative in certain points. We consider this equation
assuming that the particle paths in the medium are governed by a random process
with a variance which depends in a polynomial way on the velocity. Given an
initial distribution of the particles which is uniform in space and with the
initial velocity linearly depending on the position we show both analytically
and numerically that there exists a threshold effect: if the power in the above
variance is less than 1, then the noise does not influence the solution
behavior, in the following sense: the mean of the velocity when we keep the
value of position fixed goes to infinity outside the origin. If however the
power is larger or equal 1, then this mean decays to zero as the time tends to
a critical value.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 06:45:51 GMT"
},
{
"version": "v2",
"created": "Sat, 18 Aug 2007 04:34:32 GMT"
},
{
"version": "v3",
"created": "Tue, 5 Aug 2008 17:15:19 GMT"
}
] | 2009-06-04T00:00:00 | [
[
"Albeverio",
"Sergio",
""
],
[
"Rozanova",
"Olga",
""
]
] |
0708.2321 | Alexandre B. Tsybakov | Jean-Yves Audibert, Alexandre B. Tsybakov | Fast learning rates for plug-in classifiers | Published at http://dx.doi.org/10.1214/009053606000001217 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org) | Annals of Statistics 2007, Vol. 35, No. 2, 608-633 | 10.1214/009053606000001217 | IMS-AOS-AOS0231 | math.ST stat.TH | null | It has been recently shown that, under the margin (or low noise) assumption,
there exist classifiers attaining fast rates of convergence of the excess Bayes
risk, that is, rates faster than $n^{-1/2}$. The work on this subject has
suggested the following two conjectures: (i) the best achievable fast rate is
of the order $n^{-1}$, and (ii) the plug-in classifiers generally converge more
slowly than the classifiers based on empirical risk minimization. We show that
both conjectures are not correct. In particular, we construct plug-in
classifiers that can achieve not only fast, but also super-fast rates, that is,
rates faster than $n^{-1}$. We establish minimax lower bounds showing that the
obtained rates cannot be improved.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:14:47 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Audibert",
"Jean-Yves",
""
],
[
"Tsybakov",
"Alexandre B.",
""
]
] |
0708.2322 | Gunn Quznetsov A. | G. Quznetsov | Zero | 23 pages, 4 png pictures | null | null | null | physics.gen-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | You shall not find any new physics, because all physical events are
interpreted well-known particles (leptons, quarks, photons, gluons, W-bosons,
Z-boson) and forces which have long known (electroweak, gravity, strong
interactions).
Contents: 1. Pointlike events and probability. 2. Leptons' moving equations
and masses. 3. Fermion-antifermion asommetry. 4. Electroweak equations. 5.
Chromatic states and gluons. 6. Asimptotic freedom, confinement, Newton's
gravity. 7. Dark energy and dark matter. 8. Events and particles. 9.
Conclusion.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:16:45 GMT"
},
{
"version": "v2",
"created": "Sun, 12 Jun 2011 02:53:16 GMT"
}
] | 2011-06-14T00:00:00 | [
[
"Quznetsov",
"G.",
""
]
] |
0708.2323 | Mohamad Ali Jafarizadeh | M. A. Jafarizadeh, M. Rezaei, N. Karimi, A. R. Amiri | Optimal Unambiguous Discrimination of Quantum States | 33 pages, 4 figures | null | 10.1103/PhysRevA.77.042314 | null | quant-ph | null | Unambiguously distinguishing between nonorthogonal but linearly independent
quantum states is a challenging problem in quantum information processing. In
this work, an exact analytic solution to an optimum measurement problem
involving an arbitrary number of pure linearly independent quantum states is
presented. To this end, the relevant semi-definite programming task is reduced
to a linear programming one with a feasible region of polygon type which can be
solved via simplex method. The strength of the method is illustrated through
some explicit examples. Also using the close connection between the
Lewenstein-Sanpera decomposition(LSD) and semi-definite programming approach,
the optimal positive operator valued measure for some of the well-known
examples is obtain via Lewenstein-Sanpera decomposition method. {\bf Keywords:}
Optimal Unambiguous State Discrimination, Linear Programming,
Lewenstein-Sanpera decomposition. {\bf PACs Index: 03.67.Hk, 03.65.Ta, 42.50.-p
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:18:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jafarizadeh",
"M. A.",
""
],
[
"Rezaei",
"M.",
""
],
[
"Karimi",
"N.",
""
],
[
"Amiri",
"A. R.",
""
]
] |
0708.2324 | Christian Wuthrich | Hajnal Andreka (1), Istvan Nemeti (1) and Christian Wuthrich (2) ((1)
Renyi Institute of Mathematics, Budapest, (2) University of California, San
Diego) | A twist in the geometry of rotating black holes: seeking the cause of
acausality | 21 pages, 5 figures; replaced to match published version forthcoming
in General Relativity and Gravitation | Gen.Rel.Grav.40:1809-1823,2008 | 10.1007/s10714-007-0577-1 | null | gr-qc physics.hist-ph | null | We investigate Kerr-Newman black holes in which a rotating charged
ring-shaped singularity induces a region which contains closed timelike curves
(CTCs). Contrary to popular belief, it turns out that the time orientation of
the CTC is opposite to the direction in which the singularity or the ergosphere
rotates. In this sense, CTCs "counter-rotate" against the rotating black hole.
We have similar results for all spacetimes sufficiently familiar to us in which
rotation induces CTCs. This motivates our conjecture that perhaps this
counter-rotation is not an accidental oddity particular to Kerr-Newman
spacetimes, but instead there may be a general and intuitively comprehensible
reason for this.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:46:42 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jan 2008 17:16:00 GMT"
}
] | 2012-07-04T00:00:00 | [
[
"Andreka",
"Hajnal",
""
],
[
"Nemeti",
"Istvan",
""
],
[
"Wuthrich",
"Christian",
""
]
] |
0708.2325 | Victor Barsan | Victor Barsan | A two-parameter generalization of the complete elliptic integral of
second kind | null | null | null | null | math-ph math.MP | null | A two-parameter generalization of the complete elliptic integral of second
kind is expressed in terms of the Appell function $F_{4}$. This function is
further reduced to a quite simple bilinear form in the complete elliptic
integrals $K$ and $E$. The physical applications are briefly mentioned.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:37:54 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Barsan",
"Victor",
""
]
] |
0708.2326 | Stephen Wilson | Stephen D. Wilson, Shiliang Li, Jun Zhao, Gang Mu, Hai-hu Wen, Jeffrey
W. Lynn, Paul G. Freeman, Louis-Pierre Regnault, Klaus Habicht, Pengcheng Dai | Quantum spin correlations through the superconducting-normal phase
transition in electron-doped superconducting Pr0.88LaCe0.12CuO4-d | PDF Format: 35 pages, 4 main text figures, 6 supplemental figures;
Accepted for publication in PNAS | null | 10.1073/pnas.0704822104 | null | cond-mat.supr-con cond-mat.str-el | null | The quantum spin fluctuations of the S = 1/2 Cu ions are important in
determining the physical properties of the high-transition temperature
(high-Tc) copper oxide superconductors, but their possible role in the electron
pairing for superconductivity remains an open question. The principal feature
of the spin fluctuations in optimally doped high-Tc superconductors is a well
defined magnetic resonance whose energy (Er) tracks Tc (as the composition is
varied) and whose intensity develops like an order parameter in the
superconducting state. We show that the suppression of superconductivity and
its associated condensation energy by a magnetic field in the electron-doped
high-Tc superconductor, Pr0.88LaCe0.12CuO4-d (Tc = 24 K), is accompanied by the
complete suppression of the resonance and the concomitant emergence of static
antiferromagnetic (AF) order. Our results demonstrate that the resonance is
intimately related to the superconducting condensation energy, and thus suggest
that it plays a role in the electron pairing and superconductivity.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:45:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wilson",
"Stephen D.",
""
],
[
"Li",
"Shiliang",
""
],
[
"Zhao",
"Jun",
""
],
[
"Mu",
"Gang",
""
],
[
"Wen",
"Hai-hu",
""
],
[
"Lynn",
"Jeffrey W.",
""
],
[
"Freeman",
"Paul G.",
""
],
[
"Regnault",
"Louis-Pierre",
""
],
[
"Habicht",
"Klaus",
""
],
[
"Dai",
"Pengcheng",
""
]
] |
0708.2327 | Alireza Abdollahi | Alireza Abdollahi and A. Mohammadi Hassanabadi | Non-cyclic graph of a group | null | null | null | null | math.GR math.CO | null | We associate a graph $\Gamma_G$ to a non locally cyclic group $G$ (called the
non-cyclic graph of $G$) as follows: take $G\backslash Cyc(G)$ as vertex set,
where $Cyc(G)=\{x\in G | \left<x,y\right> \text{is cyclic for all} y\in G\}$,
and join two vertices if they do not generate a cyclic subgroup. We study the
properties of this graph and we establish some graph theoretical properties
(such as regularity) of this graph in terms of the group ones. We prove that
the clique number of $\Gamma_G$ is finite if and only if $\Gamma_G$ has no
infinite clique. We prove that if $G$ is a finite nilpotent group and $H$ is a
group with $\Gamma_G\cong\Gamma_H$ and $|Cyc(G)|=|Cyc(H)|=1$, then $H$ is a
finite nilpotent group.
We give some examples of groups $G$ whose non-cyclic graphs are ``unique'',
i.e., if $\Gamma_G\cong \Gamma_H$ for some group $H$, then $G\cong H$. In view
of these examples, we conjecture that every finite non-abelian simple group has
a unique non-cyclic graph. Also we give some examples of finite non-cyclic
groups $G$ with the property that if $\Gamma_G \cong \Gamma_H$ for some group
$H$, then $|G|=|H|$. These suggest the question whether the latter property
holds for all finite non-cyclic groups.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 07:57:49 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Abdollahi",
"Alireza",
""
],
[
"Hassanabadi",
"A. Mohammadi",
""
]
] |
0708.2328 | Maxim Dvornikov | Maxim Dvornikov (University of Jyv\"askyl\"a and IZMIRAN) | Neutrino oscillations in matter and in twisting magnetic fields | 13 pages, 1 eps figure, RevTeX4. The paper was significantly revised.
Title was changed, two new sections (Secs. IV and V), devoted to quantum
mechanical treatment of neutrino oscillations and possible applications, were
added. Many examples were included throughout the text. Final version to be
published in J. Phys. G | J.Phys.G35:025003,2008 | 10.1088/0954-3899/35/2/025003 | null | hep-ph hep-th | null | We find the solution to the Dirac equation for a massive neutrino with a
magnetic moment propagating in background matter and interacting with the
twisting magnetic field. In frames of the relativistic quantum mechanics
approach to the description of neutrino evolution we use the obtained solution
to derive neutrino wave functions satisfying the given initial condition. We
apply the results to the analysis of neutrino spin oscillations in matter under
the influence of the twisting magnetic field. Then on the basis of the yielded
results we describe spin-flavor oscillations of Dirac neutrinos that mix and
have non-vanishing matrix of magnetic moments. We again formulate the initial
condition problem, derive neutrinos wave functions and calculate the transition
probabilities for different magnetic moments matrices. The consistency of the
obtained results with the quantum mechanical treatment of spin-flavor
oscillations is discussed. We also consider several applications to
astrophysical and cosmological neutrinos.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 08:00:05 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 13:08:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dvornikov",
"Maxim",
"",
"University of Jyväskylä and IZMIRAN"
]
] |
0708.2329 | Nicolai Nygaard | N. Nygaard, R. Piil and K. Molmer | Feshbach Molecules in a One-dimensional Optical Lattice | 4 pages, 3 figures | Phys. Rev. A 77, 021601(R) (2008) | 10.1103/PhysRevA.77.021601 | null | cond-mat.other quant-ph | null | We present the theory of a pair of atoms in a one-dimensional optical lattice
interacting via a narrow Feshbach resonance. Using a two-channel description of
the resonance, we derive analytic results for the scattering states inside the
continuum band and the discrete bound states outside the band. We identify a
Fano resonance profile, and the survival probability of a molecule when swept
through the Bloch band of scattering states by varying an applied magnetic
field. We discuss how these results may be used to investigate the importance
of the structured nature of the continuum in experiments.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 08:00:10 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Feb 2008 07:45:13 GMT"
}
] | 2008-02-05T00:00:00 | [
[
"Nygaard",
"N.",
""
],
[
"Piil",
"R.",
""
],
[
"Molmer",
"K.",
""
]
] |
0708.2330 | Jean Berney | Jean Berney, Marcia T. Portella-Oberli and Benoit Deveaud | Light dressed-excitons in an incoherent-electron sea: Evidence for
Mollow-triplet and Autler-Townes doublet | null | null | 10.1103/PhysRevB.77.121301 | null | cond-mat.mtrl-sci | null | We demonstrate that the interaction between excitons and a sea of incoherent
electrons does not preclude excitons dressing by light. We investigate the role
of exciton-electron scattering in the light dressing by measuring the dynamical
absorption spectrum of a modulation-doped CdTe quantum well, which shows a
clear evidence for significant electron scattering of the excitonic states. We
show the occurrence of dressed and correlated excitons by detecting quantum
coherent interferences through excitonic Autler-Townes doublet and ac Stark
splitting, which evolves to Mollow triplet with gain. We also evidence the
partial inhibition of the electron-exciton scattering by exciton-light
coupling.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 08:28:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Berney",
"Jean",
""
],
[
"Portella-Oberli",
"Marcia T.",
""
],
[
"Deveaud",
"Benoit",
""
]
] |
0708.2331 | Gopakumar Gopinadhanpillai | G. Gopakumar, Minh Tho Nguyen and Arnout Ceulemans | The Boron Buckyball has an Unexpected Th Symmetry | 10 pages, 1 Table, 2 Figures | null | 10.1016/j.cplett.2007.11.030 | null | cond-mat.other | null | The boron buckyball avoids the high symmetry icosahedral cage structure. The
previously reported Ih symmetric structure is not an energy minimum in the
potential energy surface and exhibits a spontaneous symmetry breaking to yield
a puckered cage with a rare Th symmetry. The HOMO-LUMO gap is twice as large as
the reported value and amounts to 1.94 eV at B3LYP/6-31G(d) level. The valence
orbital structure of boron buckyball is identical to the one in the carbon
analogue.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 08:49:53 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Dec 2007 08:43:01 GMT"
}
] | 2007-12-11T00:00:00 | [
[
"Gopakumar",
"G.",
""
],
[
"Nguyen",
"Minh Tho",
""
],
[
"Ceulemans",
"Arnout",
""
]
] |
0708.2332 | TianXin Li | TianXin Li, PingPing Chen, DaYuan Xiong, ZhaoLin Liu, XuMing Zhang,
ChangSheng Xia, ZhiFeng Li, XiaoShuang Chen and Wei Lu | Metastable state involved resonant tunneling through single InAs/GaAs
quantum dot | 12 pages, 6 figures | null | null | null | quant-ph | null | A scheme of resonant tunneling through the metastable state of semiconductor
quantum dot is presented and implemented in the transport study of freestanding
InAs quantum dots grown on GaAs(001) under illumination using conductive atomic
force microscopy. The metastable state is achieved by capturing one
photoexcited Fermi hole in the valence energy level of InAs quantum dot.
Resonant tunneling through single quantum dot can be observed at room
temperature due to the existence of metastable state. The amplitude of
tunneling current depends on the barrier arrangement and the concentration of
photoexcited holes around the quantum dot, but is found steady when the height
of dot varies from 1.8 to 9.9 nm, which are in good agreement with the proposed
model. The experiment demonstrates a solution of room temperature operated
single electron device to amplify the photocurrent by the singularity of
resonant tunneling in epitaxial quantum dot.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 09:01:49 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Li",
"TianXin",
""
],
[
"Chen",
"PingPing",
""
],
[
"Xiong",
"DaYuan",
""
],
[
"Liu",
"ZhaoLin",
""
],
[
"Zhang",
"XuMing",
""
],
[
"Xia",
"ChangSheng",
""
],
[
"Li",
"ZhiFeng",
""
],
[
"Chen",
"XiaoShuang",
""
],
[
"Lu",
"Wei",
""
]
] |
0708.2333 | Ming Shi | M. Shi, J. Chang, S. Pailh\'es, M. R. Norman, J. C. Campuzano, M.
Mansson, T. Claesson, O. Tjernberg, A. Bendounan, L. Patthey, N. Momono, M.
Oda, M. Ido, C. Mudry and J. Mesot | The coherent {\it d}-wave superconducting gap in underdoped
La$_{2-x}$Sr$_{x}$CuO$_4$ as studied by angle-resolved photoemission | Accepted by Phys. Rev. Lett | Phys. Rev. Lett 101, 047002 (2008) | 10.1103/PhysRevLett.101.047002 | null | cond-mat.supr-con cond-mat.str-el | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present angle-resolved photoemission spectroscopy (ARPES) data on
moderately underdoped La$_{1.855}$Sr$_{0.145}$CuO$_4$ at temperatures below and
above the superconducting transition temperature. Unlike previous studies of
this material, we observe sharp spectral peaks along the entire underlying
Fermi surface in the superconducting state. These peaks trace out an energy gap
that follows a simple {\it d}-wave form, with a maximum superconducting gap of
14 meV. Our results are consistent with a single gap picture for the cuprates.
Furthermore our data on the even more underdoped sample
La$_{1.895}$Sr$_{0.105}$CuO$_4$ also show sharp spectral peaks, even at the
antinode, with a maximum superconducting gap of 26 meV.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 09:57:29 GMT"
},
{
"version": "v2",
"created": "Sun, 27 Jul 2008 08:43:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Shi",
"M.",
""
],
[
"Chang",
"J.",
""
],
[
"Pailhés",
"S.",
""
],
[
"Norman",
"M. R.",
""
],
[
"Campuzano",
"J. C.",
""
],
[
"Mansson",
"M.",
""
],
[
"Claesson",
"T.",
""
],
[
"Tjernberg",
"O.",
""
],
[
"Bendounan",
"A.",
""
],
[
"Patthey",
"L.",
""
],
[
"Momono",
"N.",
""
],
[
"Oda",
"M.",
""
],
[
"Ido",
"M.",
""
],
[
"Mudry",
"C.",
""
],
[
"Mesot",
"J.",
""
]
] |
0708.2334 | Mikhail V. Fistul | M. V. Fistul, V. M. Vinokur, T. I. Baturina | Collective transport in the insulating state of Josephson junction
arrays | 4 pages, 2 figures; typos corrected, new figures, an improved fit to
experimental data | null | 10.1103/PhysRevLett.100.086805 | null | cond-mat.supr-con cond-mat.mes-hall | null | We investigate collective Cooper-pair transport of one- and two-dimensional
Josephson junction arrays in the insulating state. We derive an analytical
expression for the current-voltage characteristic revealing thermally activated
conductivity at small voltages and threshold voltage depinning. The activation
energy and the related depinning voltage represent a dynamic Coulomb barrier
for collective charge transfer over the whole system and scale with the system
size. We show that both quantities are non-monotonic functions of magnetic
field. We propose that formation of the dynamic Coulomb barrier as well as the
size scaling of the activation energy and the depinning threshold voltage, are
consequences of the mutual phase synchronization. We apply the results for
interpretation of experimental data in disordered films near the
superconductor-insulator transition.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:46:46 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Oct 2007 13:42:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fistul",
"M. V.",
""
],
[
"Vinokur",
"V. M.",
""
],
[
"Baturina",
"T. I.",
""
]
] |
0708.2335 | Vladimir Fedoseyev | V. G. Fedoseyev | 2D shift of the centre of gravity of the light beam carrying orbital
angular momentum, which accompanies reflection from a lossy medium | 16 pages, 10 figures | null | null | null | physics.optics | null | It is shown that after reflection from a lossy medium the $s$- or
$p$-polarized paraxial light beam carrying the orbital angular momentum suffers
the 2D shift of the beam's centre of gravity relative the geometric optic axis.
The mutually orthogonal components of this shift are expressed through the real
and imaginary parts of the common complex quantity. The features of the 2D
vector, which describes the shift, are analyzed.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 09:31:38 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Fedoseyev",
"V. G.",
""
]
] |
0708.2336 | Dominik Scheder | Dominik Scheder | Unsatisfiable Linear k-CNFs Exist, for every k | 11 pages | null | null | null | cs.DM cs.CC cs.LO | null | We call a CNF formula linear if any two clauses have at most one variable in
common. Let Linear k-SAT be the problem of deciding whether a given linear
k-CNF formula is satisfiable. Here, a k-CNF formula is a CNF formula in which
every clause has size exactly k. It was known that for k >= 3, Linear k-SAT is
NP-complete if and only if an unsatisfiable linear k-CNF formula exists, and
that they do exist for k >= 4. We prove that unsatisfiable linear k-CNF
formulas exist for every k. Let f(k) be the minimum number of clauses in an
unsatisfiable linear k-CNF formula. We show that f(k) is Omega(k2^k) and
O(4^k*k^4), i.e., minimum size unsatisfiable linear k-CNF formulas are
significantly larger than minimum size unsatisfiable k-CNF formulas. Finally,
we prove that, surprisingly, linear k-CNF formulas do not allow for a larger
fraction of clauses to be satisfied than general k-CNF formulas.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 09:44:21 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Scheder",
"Dominik",
""
]
] |
0708.2337 | Yuri Levin | R. G. Berkhout (Leiden Observatory) and Yuri Levin (Leiden Observatory
and Lorentz Institute) | Evolution of the bursting-layer wave during a Type 1 X-ray burst | 8 pages, submitted to MNRAS | null | 10.1111/j.1365-2966.2008.12897.x | null | astro-ph | null | In a popular scenario due to Heyl, quasi periodic oscillations (QPOs) which
are seen during type 1 X-ray bursts are produced by giant travelling waves in
neutron-star oceans. Piro and Bildsten have proposed that during the burst
cooling the wave in the bursting layer may convert into a deep crustal
interface wave, which would cut off the visible QPOs. This cut-off would help
explain the magnitude of the QPO frequency drift, which is otherwise
overpredicted by a factor of several in Heyl's scenario. In this paper, we
study the coupling between the bursting layer and the deep ocean. The coupling
turns out to be weak and only a small fraction of the surface-wave energy gets
transferred to that of the crustal-interface wave during the burst. Thus the
crustal-interface wave plays no dynamical role during the burst, and no early
QPO cut-off should occur.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:10:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Berkhout",
"R. G.",
"",
"Leiden Observatory"
],
[
"Levin",
"Yuri",
"",
"Leiden Observatory\n and Lorentz Institute"
]
] |
0708.2338 | Toshiya Hikihara | Toshiya Hikihara, Shoji Yamamoto | Magnetic Phase Diagram of Spin-1/2 Two-Leg Ladder with Four-Spin Ring
Exchange | 18pages, 7 figures | J. Phys. Soc. Jpn. 77, 014709 (2008). | 10.1143/JPSJ.77.014709 | null | cond-mat.str-el | null | We study the spin-1/2 two-leg Heisenberg ladder with four-spin ring exchanges
under a magnetic field. We introduce an exact duality transformation which is
an extension of the spin-chirality duality developed previously and yields a
new self-dual surface in the parameter space. We then determine the magnetic
phase diagram using the numerical approaches of the density-matrix
renormalization-group and exact diagonalization methods. We demonstrate the
appearance of a magnetization plateau and the Tomonaga-Luttinger liquid with
dominant vector-chirality quasi-long-range order for a wide parameter regime of
strong ring exchange. A "nematic" phase, in which magnons form bound pairs and
the magnon-pairing correlation functions dominate, is also identified.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:14:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hikihara",
"Toshiya",
""
],
[
"Yamamoto",
"Shoji",
""
]
] |
0708.2339 | Takashi Inoue | Takashi Inoue | A pentaquark picture of Lambda(1405) | 3 pages, 1 figure, to appear in the proceedings of the International
Nuclear Physics Conference(INPC) 2007, June 3-8, Tokyo, Japan | null | null | null | hep-ph | null | We test a pentaquark model of the negative parity hyperon Lambda(1405). We
use a model where valence four quarks and one antiquark move in a potential
relativistically and interact with each other and themselves through gluon and
NG boson. Fall-apart decay rate of the system is studied and strong model
dependence is pointed out.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:19:09 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Inoue",
"Takashi",
""
]
] |
0708.2340 | Lance Miller | L. Miller, T. D. Kitching, C. Heymans, A. F. Heavens, L. Van Waerbeke | Bayesian Galaxy Shape Measurement for Weak Lensing Surveys -I.
Methodology and a Fast Fitting Algorithm | 11 pages, 4 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12363.x | null | astro-ph | null | The principles of measuring the shapes of galaxies by a model-fitting
approach are discussed in the context of shape-measurement for surveys of weak
gravitational lensing. It is argued that such an approach should be optimal,
allowing measurement with maximal signal-to-noise, coupled with estimation of
measurement errors. The distinction between likelihood-based and Bayesian
methods is discussed. Systematic biases in the Bayesian method may be evaluated
as part of the fitting process, and overall such an approach should yield
unbiased shear estimation without requiring external calibration from
simulations. The principal disadvantage of model-fitting for large surveys is
the computational time required, but here an algorithm is presented that
enables large surveys to be analysed in feasible computation times. The method
and algorithm is tested on simulated galaxies from the Shear TEsting Program
(STEP).
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 14:23:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Miller",
"L.",
""
],
[
"Kitching",
"T. D.",
""
],
[
"Heymans",
"C.",
""
],
[
"Heavens",
"A. F.",
""
],
[
"Van Waerbeke",
"L.",
""
]
] |
0708.2341 | Hacene Belbachir | Hacene Belbachir (USTHB) | Unimodality of ordinary multinomials and maximal probabilities of
convolution powers of discrete uniform distribution | 8 pages | null | null | null | math.PR math.CO | null | We establish the unimodality and the asymptotic strong unimodality of the
ordinary multinomials and give their smallest mode leading to the expression of
the maximal probability of convolution powers of the discrete uniform
distribution. We conclude giving the generating functions of the sequence of
generalized ordinary multinomials and for an extension of the sequence of
maximal probabilities for convolution power of discrete uniform distribution.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:57:06 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Belbachir",
"Hacene",
"",
"USTHB"
]
] |
0708.2342 | Chiara Zanini | Chiara Zanini and Fabio Zanolin | Complex dynamics in a nerve fiber model with periodic coefficients | 29 pages, 5 figures | null | null | null | math.DS | null | We deal with the periodic boundary value problem for a second-order nonlinear
ODE which includes the case of the Nagumo type equation $v_{xx} - g v + n(x)
F(v) = 0,$ previously considered by Grindrod and Sleeman and by Chen and Bell
in the study of nerve fiber models. In some recent works we discussed the case
of nonexistence of nontrivial solutions as well as the case in which many
positive periodic solutions may arise, the different situations depending by
threshold parameters related to the weight function $n(x).$ Here we show that
for a step function $n(x)$ (or for small perturbations of it) it is possible to
obtain infinitely many periodic solutions and chaotic dynamics, due to the
presence of a topological horseshoe (according to Kennedy and Yorke).
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 10:57:55 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Zanini",
"Chiara",
""
],
[
"Zanolin",
"Fabio",
""
]
] |
0708.2343 | Ramon Munoz-Tapia | J. Calsamiglia, R. Munoz-Tapia, Ll. Masanes, A. Acin, E. Bagan | The quantum Chernoff bound as a measure of distinguishability between
density matrices: application to qubit and Gaussian states | 16 pages | Phys. Rev. A 77, 032311 (2008) | 10.1103/PhysRevA.77.032311 | null | quant-ph | null | Hypothesis testing is a fundamental issue in statistical inference and has
been a crucial element in the development of information sciences. The Chernoff
bound gives the minimal Bayesian error probability when discriminating two
hypotheses given a large number of observations. Recently the combined work of
Audenaert et al. [Phys. Rev. Lett. 98, 160501] and Nussbaum and Szkola
[quant-ph/0607216] has proved the quantum analog of this bound, which applies
when the hypotheses correspond to two quantum states. Based on the quantum
Chernoff bound, we define a physically meaningful distinguishability measure
and its corresponding metric in the space of states; the latter is shown to
coincide with the Wigner-Yanase metric. Along the same lines, we define a
second, more easily implementable, distinguishability measure based on the
error probability of discrimination when the same local measurement is
performed on every copy. We study some general properties of these measures,
including the probability distribution of density matrices, defined via the
volume element induced by the metric, and illustrate their use in the
paradigmatic cases of qubits and Gaussian infinite-dimensional states.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:02:40 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 18:53:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Calsamiglia",
"J.",
""
],
[
"Munoz-Tapia",
"R.",
""
],
[
"Masanes",
"Ll.",
""
],
[
"Acin",
"A.",
""
],
[
"Bagan",
"E.",
""
]
] |
0708.2344 | Vladimir Peskov | B. Clark, A. G. Agocs, R. Oliveira, V. Peskov, Pietropaolo, Picchi | Developments and the preliminary tests of Resistive GEMs manufactured by
a screen printing technology | null | JINST 3:P02012,2008 | 10.1088/1748-0221/3/02/P02012 | null | physics.ins-det | null | We report promising initial results obtained with new resistive-electrode GEM
(RETGEM) detectors manufactured, for the first time, using screen printing
technology. These new detectors allow one to reach gas gains nearly as high as
with ordinary GEM-like detectors with metallic electrodes; however, due to the
high resistivity of its electrodes the RETGEM, in contrast to ordinary
hole-type detectors, has the advantage of being fully spark protected. We
discovered that RETGEMs can operate stably and at high gains in noble gases and
in other badly quenched gases, such as mixtures of noble gases with air and in
pure air; therefore, a wide range of practical applications, including
dosimetry and detection of dangerous gases, is foreseeable. To promote a better
understanding of RETGEM technology some comparative studies were completed with
metallic-electrode thick GEMs. A primary benefit of these new RETGEMs is that
the screen printing technology is easily accessible to many research
laboratories. This accessibility encourages the possibility to manufacture
these GEM-like detectors with the electrode resistivity easily optimized for
particular experimental or practical applications.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:17:00 GMT"
}
] | 2009-12-10T00:00:00 | [
[
"Clark",
"B.",
""
],
[
"Agocs",
"A. G.",
""
],
[
"Oliveira",
"R.",
""
],
[
"Peskov",
"V.",
""
],
[
"Pietropaolo",
"",
""
],
[
"Picchi",
"",
""
]
] |
0708.2345 | Navinder Singh | Navinder Singh | Onsager-Machlup theory and work fluctuation theorem for a harmonically
driven Brownian particle | 6 pages, 1 figure | J. Stat. Phys. Vol. 131, 405 (2008) | 10.1007/s10955-008-9503-5 | null | cond-mat.stat-mech | null | We extend Tooru-Cohen analysis for nonequilirium steady state(NSS) of a
Brownian particle to nonequilibrium oscillatory state (NOS) of Brownian
particle by considering time dependent external drive protocol. We consider an
unbounded charged Brownian particle in the presence of an oscillating electric
field and prove work fluctuation theorem, which is valid for any initial
distribution and at all times. For harmonically bounded and constantly dragged
Brownian particle considered by Tooru and Cohen, work fluctuation theorem is
valid for any initial condition(also NSS), but only in large time limit. We use
Onsager-Machlup Lagrangian with a constraint to obtain frequency dependent work
distribution function, and describe entropy production rate and properties of
dissipation functions for the present system using Onsager-Machlup functional.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:17:24 GMT"
}
] | 2008-04-20T00:00:00 | [
[
"Singh",
"Navinder",
""
]
] |
0708.2346 | Aurelien Perera aup | Aurelien Perera, Franjo Sokolic and Larisa Zoranic | Apparent density fluctuations in N-constant ensemble simulations | 15 pages, 5 figures | null | null | null | physics.chem-ph physics.comp-ph | null | In computer simulations performed in constant number of particles ensembles,
although the total number of particles N contained in the simulation box does
not fluctuate, hence giving a zero apparent compressibility, there are still
local fluctuations in the number of particles. It is shown herein that these
apparent fluctuations produce a compressibility that can be computed from the
calculated radial distribution function, and which matches to a great accuracy
the compressibility of the fluid for the open system. This statement implies
that the radial distribution function evaluated in simulation of constant
number of particles is identical to that evaluated in the grand canonical
ensemble, for the entire distance range within half-box width. This is
illustrated for the hard sphere and Lennard-Jones fluids and for molecular
models of water. The origin of this apparent fluctuation is that the bulk of
the remaining particles, outside the range over which the distribution function
is calculated, act as a reservoir of particles for those within this range,
thanks to the periodic boundary conditions. The implications on the calculation
of the Kirkwood-Buff integrals are discussed.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:26:44 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Perera",
"Aurelien",
""
],
[
"Sokolic",
"Franjo",
""
],
[
"Zoranic",
"Larisa",
""
]
] |
0708.2347 | Hacene Belbachir | Hacene Belbachir (USTHB), Farid Bencherif (USTHB) | Sums of products of generalized Fibonacci and Lucas numbers | null | null | null | null | math.NT math.CO | null | In this paper, we establish several formulae for sums and alternating sums of
products of generalized Fibonacci and Lucas numbers. In particular, we recover
and extend all results of Z. Cerin and Z. Cerin & G. M. Gianella, more easily.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:27:12 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Belbachir",
"Hacene",
"",
"USTHB"
],
[
"Bencherif",
"Farid",
"",
"USTHB"
]
] |
0708.2348 | Anton Tikhonov Valerievich | Anton Tikhonov and Anatoly Klypin | Properties of voids in the Local Volume | 5 pages 1 figure. To appear in proceedings of the conference
"Galaxies in the Local Volume", Sydney, 8 to 13 July 2007 | null | 10.1007/978-1-4020-6933-8_5 | null | astro-ph | null | Current explanation of the overabundance of dark matter subhalos in the Local
Group (LG) indicates that there maybe a limit on mass of a halo, which can host
a galaxy. This idea can be tested using voids in the distribution of galaxies:
at some level small voids should not contain any (even dwarf) galaxies. We use
observational samples complete to M_B=-12 with distances less than 8 Mpc to
construct the void function (VF): the distribution of sizes of voids empty of
any galaxies. There are ~ 30 voids with sizes ranging from 1 to 5 Mpc. We also
study the distribution of dark matter halos in very high resolution simulations
of the LCDM model. The theoretical VF matches the observations remarkably well
only if we use halos with circular velocities larger than 45 +/- 10 km/s. This
agrees with the Local Group predictions. Small voids look quite similar to heir
giant cousins: the density has a minimum at the center of a void and it
increases as we get closer to the border. Thus, both the Local Group data and
the nearby voids indicate that isolated halos below 45 +/- 10 km/s must not
host galaxies and that small (few Mpc) voids are truly dark.
| [
{
"version": "v1",
"created": "Fri, 17 Aug 2007 11:45:24 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Tikhonov",
"Anton",
""
],
[
"Klypin",
"Anatoly",
""
]
] |
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