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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.4230 | Reza Asgari | Marco Polini, Reza Asgari, Giovanni Borghi, Yafis Barlas, T.
Pereg-Barnea, A.H. MacDonald | The Role of Electron-electron Interactions in Graphene ARPES Spectra | 5 Pages, 4 Figures, Submitted | Phys. Rev. B 77, 081411(R) (2008) | 10.1103/PhysRevB.77.081411 | null | cond-mat.mes-hall | null | We report on a theoretical study of the influence of electron-electron
interactions on ARPES spectra in graphene that is based on the
random-phase-approximation and on graphene's massless Dirac equation continuum
model. We find that level repulsion between quasiparticle and plasmaron
resonances gives rise to a gap-like feature at small k. ARPES spectra are
sensitive to the electron-electron interaction coupling strength $\alpha_{\rm
gr}$ and might enable an experimental determination of this material parameter.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 10:31:14 GMT"
}
] | 2008-03-03T00:00:00 | [
[
"Polini",
"Marco",
""
],
[
"Asgari",
"Reza",
""
],
[
"Borghi",
"Giovanni",
""
],
[
"Barlas",
"Yafis",
""
],
[
"Pereg-Barnea",
"T.",
""
],
[
"MacDonald",
"A. H.",
""
]
] |
0707.4231 | Michael Kapovich | Michael Kapovich | Energy of harmonic functions and Gromov's proof of Stallings' theorem | 4 figures | null | null | null | math.GR math.DG math.GT | null | We provide the details for Gromov's proof of Stallings' theorem on groups
with infinitely many ends using harmonic functions. The main technical result
of the paper is a compactness theorem for a certain family of harmonic
functions.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 10:38:56 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Kapovich",
"Michael",
""
]
] |
0707.4232 | Bhaskar Kaviraj Mr. | F. Alves, B. Kaviraj, L. Abi Rached, J. Moutoussamy and C. Coillot | Performances of a Newly High Sensitive Trilayer F/Cu/F GMI Sensor | 4 pages, 6 figures, Sensors and Actuators A (in review) | Solid-State Sensors, Actuators and Microsystems Conference, Vol 2
(2007) pp 2581-2584 | 10.1109/SENSOR.2007.4300699 | null | cond-mat.mtrl-sci | null | We have selected stress-annealed nanocrystalline Fe-based ribbons for
ferromagnetic/copper/ferromagnetic sensors exhibiting high magneto-impedance
ratio. Longitudinal magneto-impedance reaches 400% at 60 kHz and longitudinal
magneto-resistance increases up to 1300% around 200 kHz.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 10:42:27 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 08:13:01 GMT"
}
] | 2007-10-08T00:00:00 | [
[
"Alves",
"F.",
""
],
[
"Kaviraj",
"B.",
""
],
[
"Rached",
"L. Abi",
""
],
[
"Moutoussamy",
"J.",
""
],
[
"Coillot",
"C.",
""
]
] |
0707.4233 | Anirban Pathak | Anindita Banerjee and Anirban Pathak | On the Synthesis of Sequential Reversible Circuit | 9 pages, 8 Figures, LaTeX 2e, | null | null | null | quant-ph | null | Reversible circuits for SR flip flop, JK flip flop, D flip flop, T flip flop,
Master Slave D flip flop and Master Slave JK flip flop have been provided with
three different logical approaches. All the circuits have been optimized with
the help of existing local optimization algorithms (e.g. template matching,
moving rule and deletion rule) and the optimized sequential circuits have been
compared with the earlier proposals for the same. It has been shown that the
present proposals have lower gate complexities and lower number of garbage bits
compared to the earlier proposals. It has also been shown that the advantage in
gate count obtained in some of the earlier proposals by introduction of New
gates is an \textcolor{black}{artifact} and if it is allowed then every circuit
block (unless there is a measurement) can be reduced to a single gate. Further,
it is shown that a reversible flip flop can be constructed even without a
feedback. In this context, some important conceptual issues related to the
designing and optimization of sequential reversible circuits have also been
addressed.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 11:10:48 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Banerjee",
"Anindita",
""
],
[
"Pathak",
"Anirban",
""
]
] |
0707.4234 | Viviana Casasola | V. Casasola, F. Combes, D. Bettoni, G. Galletta | Molecular clouds in the center of M81 | 12 pages, 7 figures, 6 tables. Accepted for pubblication in A&A | null | 10.1051/0004-6361:20077883 | null | astro-ph | null | We investigate the molecular gas content and the excitation and fragmentation
properties in the central region of the spiral galaxy Messier 81 in both the
^{12}CO(1-0) and ^{12}CO(2-1) transitions. We have recently observed the two
transitions of CO in the M~81 center with A, B, and HERA receivers of the IRAM
30-m telescope. We find no CO emission in the inner $\sim$ 300 pc and a weak
molecular gas clump structure at a distance of around 460 pc from the nucleus.
Observations of the first two CO transitions allowed us to compute the line
ratio, and the average I_{21}/I_{10} ratio is 0.68 for the M~81 center. This
low value, atypical both of the galactic nuclei of spiral galaxies and of
interacting systems, is probably associated to diffuse gas with molecular
hydrogen density that is not high enough to excite the CO molecules. After
analyzing the clumping properties of the molecular gas in detail, we identify
very massive giant molecular associations (GMAs) in CO(2-1) emission with
masses of $\sim$ 10$^{5}$ M$_\odot$ and diameters of $\sim$ 250 pc. The deduced
N(H_{2})/I_{CO} ratio for the individually resolved GMAs, assumed to be
virialized, is a factor of $\sim$ 15 higher than the \textit{standard} Galactic
value, showing - as suspected - that the X ratio departs significantly from the
mean for galaxies with an unusual physics of the molecular gas.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 11:18:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Casasola",
"V.",
""
],
[
"Combes",
"F.",
""
],
[
"Bettoni",
"D.",
""
],
[
"Galletta",
"G.",
""
]
] |
0707.4235 | Debasish Datta | D. Datta and S. R. Bhattacharyya | Analysis of atomic depth profiles directly extracted from Rutherford
backscattering data for co-sputtered and ion irradiated Au-Ni films | Version 2 : 17 pages (with double spacing) of main text, 4 figures in
EPS format, Some text and one figure have been modified | null | null | null | cond-mat.mtrl-sci | null | Co-sputtered Au-Ni thin films having thickness of 30 nm were deposited on
Si(100) substrates and irradiated with 160 keV ^{40}Ar^{+} under ambient
condition at a number of fluences and analyzed using Rutherford backscattering
spectrometry (RBS). The variation of Au signal counts in the RBS spectra with
ion dose has been investigated. The distribution of Au, Ni and Si atoms over
various depths within the as deposited and irradiated samples have been
computed using the backscattering data by means of a direct analytical method.
Au and Si profiles have been fitted with error function and the relative
changes in variance for various ion fluences compared to that of as deposited
profiles have been studied. The spreading rates of different constituents
across the interface due to Ar ion impact have also been discussed.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 11:24:35 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 07:10:36 GMT"
}
] | 2009-04-16T00:00:00 | [
[
"Datta",
"D.",
""
],
[
"Bhattacharyya",
"S. R.",
""
]
] |
0707.4236 | Gwendal F\`eve | G. F\`eve, P. Degiovanni, Th. Jolicoeur | Quantum detection of electronic flying qubits | 15 pages, 7 figures, published version | Phys. Rev. B77, 035308 (2008) | 10.1103/PhysRevB.77.035308 | null | cond-mat.mes-hall | null | We consider a model of a detector of ballistic electrons at the edge of a
two-dimensional electron gas in the integer quantum Hall regime. The electron
is detected by capacitive coupling to a gate which is also coupled to a passive
RC circuit. Using a quantum description of this circuit, we determine the
signal over noise ratio of the detector in term of the detector
characteristics. The back-action of the detector on the incident wavepacket is
then computed using a Feynman-Vernon influence functional approach. Using
information theory, we define the appropriate notion of quantum limit for such
an "on the fly" detector. We show that our particular detector can approach the
quantum limit up to logarithms in the ratio of the measurement time over the RC
relaxation time. We argue that such a weak logarithmic effect is of no
practical significance. Finally we show that a two-electron interference
experiment can be used to probe the detector induced decoherence.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:07:34 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Apr 2008 10:30:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fève",
"G.",
""
],
[
"Degiovanni",
"P.",
""
],
[
"Jolicoeur",
"Th.",
""
]
] |
0707.4237 | Igor V. Lerner | I.V. Lerner, A.A. Varlamov and V.M. Vinokur | Fluctuation spectroscopy of granularity in superconducting structures | A final version, as published; the introduction and summary are
considerably revised | Phys. Rev. Lett. 100,117003 (2008) | 10.1103/PhysRevLett.100.117003 | null | cond-mat.supr-con cond-mat.mes-hall | null | We suggest to use `fluctuation spectroscopy' as a method to detect
granularity in a disordered metal close to a superconducting transition. We
show that with lowering temperature $T$ the resistance $R(T)$ of a system of
relatively large grains initially grows due to the fluctuation suppression of
the one-electron tunneling but decreases with further lowering $T$ due to the
coherent charge transfer of the fluctuation Cooper pairs. Under certain
conditions, such a maximum in $R(T)$ turns out to be sensitive to weak magnetic
fields due to a novel Maki -- Thompson type mechanism.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 13:33:12 GMT"
},
{
"version": "v2",
"created": "Sun, 23 Mar 2008 09:10:15 GMT"
}
] | 2008-03-26T00:00:00 | [
[
"Lerner",
"I. V.",
""
],
[
"Varlamov",
"A. A.",
""
],
[
"Vinokur",
"V. M.",
""
]
] |
0707.4238 | Stephen Appleby | S. A. Appleby, R. A. Battye | Regularized braneworlds of arbitrary codimension | 21 pages | Phys.Rev.D76:124009,2007 | 10.1103/PhysRevD.76.124009 | null | hep-ph hep-th | null | We consider a thick p-brane embedded in an n-dimensional spacetime possessing
radial symmetry in the directions orthogonal to the brane. We first consider a
static brane, and find a general fine tuning relationship between the brane and
bulk parameters required for the brane to be flat. We then consider the
cosmology of a time dependent brane in a static bulk, and find the Friedmann
equation for the brane scale factor a(t). The singularities that would
ordinarily arise when considering arbitrary codimensions are avoided by
regularizing the brane, giving it a finite profile in the transverse
dimensions. However, since we consider the brane to be a strictly local defect,
we find that the transverse dimensions must have infinite volume, and hence
gravity cannot be localized on the brane without resorting to some infra-red
cutoff.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 13:37:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Appleby",
"S. A.",
""
],
[
"Battye",
"R. A.",
""
]
] |
0707.4239 | Junsheng Fang | Junsheng Fang, Don Hadwin, Eric Nordgren, Junhao Shen | Tracial gauge norms on finite von Neumann algebras satisfying the weak
Dixmier property | 48 pages, final version, to appear in J. Funct. Anal | null | null | null | math.OA math.FA | null | In this paper we set up a representation theorem for tracial gauge norms on
finite von Neumann algebras satisfying the weak Dixmier property in terms of Ky
Fan norms. Examples of tracial gauge norms on finite von Neumann algebras
satisfying the weak Dixmier property include unitarily invariant norms on
finite factors (type ${\rm II}\sb 1$ factors and $M_n(\cc)$) and symmetric
gauge norms on $L^\infty[0,1]$ and $\cc^n$. As the first application, we obtain
that the class of unitarily invariant norms on a type ${\rm II}\sb 1$ factor
coincides with the class of symmetric gauge norms on $L^\infty[0,1]$ and von
Neumann's classical result \cite{vN} on unitarily invariant norms on
$M_n(\cc)$. As the second application, Ky Fan's dominance theorem \cite{Fan} is
obtained for finite von Neumann algebras satisfying the weak Dixmier property.
As the third application, some classical results in non-commutative
$L^p$-theory (e.g., non-commutative H$\ddot{\text{o}}$lder's inequality,
duality and reflexivity of non-commutative $L^p$-spaces) are obtained for
general unitarily invariant norms on finite factors. We also investigate the
extreme points of $\NN(\M)$, the convex compact set (in the pointwise weak
topology) of normalized unitarily invariant norms (the norm of the identity
operator is 1) on a finite factor $\M$. We obtain all extreme points of
$\NN(M_2(\cc))$ and many extreme points of $\NN(M_n(\cc))$ ($n\geq 3$). For a
type ${\rm II}\sb 1$ factor $\M$, we prove that if $t$ ($0\leq t\leq 1$) is a
rational number then the Ky Fan $t$-th norm is an extreme point of $\NN(\M)$.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 14:39:17 GMT"
},
{
"version": "v2",
"created": "Sat, 25 Aug 2007 14:53:00 GMT"
},
{
"version": "v3",
"created": "Tue, 29 Apr 2008 19:11:07 GMT"
}
] | 2008-04-29T00:00:00 | [
[
"Fang",
"Junsheng",
""
],
[
"Hadwin",
"Don",
""
],
[
"Nordgren",
"Eric",
""
],
[
"Shen",
"Junhao",
""
]
] |
0707.4240 | Junsheng Fang | Junsheng Fang, Don Hadwin | Unitarily invariant norms related to factors | 42 pages, the introduction is rewritten, minor corrections | null | null | null | math.OA math.FA | null | Let $\M$ be a semi-finite factor and let $\J(\M)$ be the set of operators $T$
in $\M$ such that $T=ETE$ for some finite projection $E$. In this paper we
obtain a representation theorem for unitarily invariant norms on $\J(\M)$ in
terms of Ky Fan norms. As an application, we prove that the class of unitarily
invariant norms on $\J(\M)$ coincides with the class of symmetric gauge norms
on a classical abelian algebra, which generalizes von Neumann's classical
result \cite{vN} on unitarily invariant norms on $M_n(\cc)$. As another
application, Ky Fan's dominance theorem \cite{Fan} is obtained for semi-finite
factors. Some classical results in non-commutative $L^p$-theory (e.g.,
non-commutative H$\ddot{\text{o}}$lder's inequality, duality and reflexivity of
non-commutative $L^p$-spaces) are extended to general unitarily invariant norms
related to semi-finite factors. We also prove that up to a scale the operator
norm is the unique unitarily invariant norm associated to a type ${\rm III}$
factor.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 15:11:48 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Apr 2008 20:45:20 GMT"
}
] | 2008-04-22T00:00:00 | [
[
"Fang",
"Junsheng",
""
],
[
"Hadwin",
"Don",
""
]
] |
0707.4241 | Gang Wu | Gang Wu and Baowen Li | Thermal rectification in carbon nanotube intramolecular junctions:
Molecular dynamics calculations | null | Phys. Rev. B 76, 085424 (2007) | 10.1103/PhysRevB.76.085424 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | We study heat conduction in (n, 0)/(2n, 0) intramolecular junctions by using
molecular dynamics method. It is found that the heat conduction is asymmetric,
namely, heat transports preferably in one direction. This phenomenon is also
called thermal rectification. The rectification is weakly dependent on the
detailed structure of connection part, but is strongly dependent on the
temperature gradient. We also study the effect of the tube radius and
intramolecular junction length on the rectification. Our study shows that the
tensile stress can increase rectification. The physical mechanism of the
rectification is explained.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 14:16:30 GMT"
}
] | 2007-08-18T00:00:00 | [
[
"Wu",
"Gang",
""
],
[
"Li",
"Baowen",
""
]
] |
0707.4242 | Robert B. Gramacy | Robert B. Gramacy, Richard J. Samworth, Ruth King | Importance Tempering | 16 pages, 2 tables, significantly shortened from version 4 in
response to referee comments, to appear in Statistics and Computing | null | null | null | stat.CO stat.AP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Simulated tempering (ST) is an established Markov chain Monte Carlo (MCMC)
method for sampling from a multimodal density $\pi(\theta)$. Typically, ST
involves introducing an auxiliary variable $k$ taking values in a finite subset
of $[0,1]$ and indexing a set of tempered distributions, say $\pi_k(\theta)
\propto \pi(\theta)^k$. In this case, small values of $k$ encourage better
mixing, but samples from $\pi$ are only obtained when the joint chain for
$(\theta,k)$ reaches $k=1$. However, the entire chain can be used to estimate
expectations under $\pi$ of functions of interest, provided that importance
sampling (IS) weights are calculated. Unfortunately this method, which we call
importance tempering (IT), can disappoint. This is partly because the most
immediately obvious implementation is na\"ive and can lead to high variance
estimators. We derive a new optimal method for combining multiple IS estimators
and prove that the resulting estimator has a highly desirable property related
to the notion of effective sample size. We briefly report on the success of the
optimal combination in two modelling scenarios requiring reversible-jump MCMC,
where the na\"ive approach fails.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 15:04:57 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 19:26:59 GMT"
},
{
"version": "v3",
"created": "Thu, 16 Aug 2007 15:35:12 GMT"
},
{
"version": "v4",
"created": "Mon, 17 Sep 2007 16:21:18 GMT"
},
{
"version": "v5",
"created": "Mon, 8 Sep 2008 15:10:25 GMT"
},
{
"version": "v6",
"created": "Mon, 3 Nov 2008 18:12:25 GMT"
}
] | 2008-11-03T00:00:00 | [
[
"Gramacy",
"Robert B.",
""
],
[
"Samworth",
"Richard J.",
""
],
[
"King",
"Ruth",
""
]
] |
0707.4243 | Panayotis Boumis | P. Boumis (1), J. Meaburn (1,2), J. Alikakos (1,3), M. P. Redman (4),
S. Akras (1,3), F. Mavromatakis (5), J. A. Lopez (6), A. Caulet (6), C. D.
Goudis (1,3) ((1) Institute of Astronomy & Astrophysics, National Observatory
of Athens, Greece, (2) Jodrell Bank Observatory, University of Manchester,
UK, (3) Astronomical Laboratory, Department of Physics, University of Patras,
Greece, (4) Department of Physics, National University of Ireland Galway,
Ireland, (5) Technological Education Institute of Crete, General Department
of Applied Science, Heraklion, Crete, Greece, (6) Instituto de Astronomia,
UNAM, Ensenada, Mexico) | Deep optical observations of the interaction of the SS 433 microquasar
jet with the W 50 radio continuum shell | 19 pages, 13 figures, 2 tables. Accepted for pubication in MNRAS | null | 10.1111/j.1365-2966.2007.12276.x | null | astro-ph | null | Four mosaics of deep, continuum-subtracted, CCD images have been obtained
over the extensive galactic radio continuum shell, W 50, which surrounds the
remarkable stellar system SS 433. Two of these mosaics in the Halpha+[N II] and
[O III] 5007 A emission lines respectively cover a field of ~2.3 x 2.5 degr^2
which contains all of W 50 but at a low angular resolution of 5 arcsec. The
third and fourth mosaics cover the eastern (in [O III] 5007 A) and western (in
Halpha+[N II]) filamentary nebulosity respectively but at an angular resolution
of 1 arcsec. These observations are supplemented by new low dispersion spectra
and longslit, spatially resolved echelle spectra. The [O III] 5007 A images
show for the first time the distribution of this emission in both the eastern
and western filaments while new Halpha+[N II] emission features are also found
in both of these regions. Approaching flows of faintly emitting material from
the bright eastern filaments of up 100 km/s in radial velocity are detected.
The present observations also suggest that the heliocentric systemic radial
velocity of the whole system is 56+-2 km/s. Furthermore, very deep imagery and
high resolution spectroscopy of a small part of the northern radio ridge of W
50 has revealed for the first time the very faint optical nebulosity associated
with this edge. It is suggested that patchy foreground dust along the ~5 kpc
sightline is inhibiting the detection of all of the optical nebulosity
associated with W 50. The interaction of the microquasar jets of SS 433 with
the W 50 shell is discussed.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 15:28:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boumis",
"P.",
""
],
[
"Meaburn",
"J.",
""
],
[
"Alikakos",
"J.",
""
],
[
"Redman",
"M. P.",
""
],
[
"Akras",
"S.",
""
],
[
"Mavromatakis",
"F.",
""
],
[
"Lopez",
"J. A.",
""
],
[
"Caulet",
"A.",
""
],
[
"Goudis",
"C. D.",
""
]
] |
0707.4244 | David Rabson | D.C. Lovelady, T.C. Richmond, A.N. Maggi, C.-M. Lo, D.A. Rabson | Distinguishing cancerous from non-cancerous cells through analysis of
electrical noise | 8 pages, 4 figures; submitted to PRE | null | 10.1103/PhysRevE.76.041908 | null | q-bio.CB q-bio.QM | null | Since 1984, electric cell-substrate impedance sensing (ECIS) has been used to
monitor cell behavior in tissue culture and has proven sensitive to cell
morphological changes and cell motility. We have taken ECIS measurements on
several cultures of non-cancerous (HOSE) and cancerous (SKOV) human ovarian
surface epithelial cells. By analyzing the noise in real and imaginary
electrical impedance, we demonstrate that it is possible to distinguish the two
cell types purely from signatures of their electrical noise. Our measures
include power-spectral exponents, Hurst and detrended fluctuation analysis, and
estimates of correlation time; principal-component analysis combines all the
measures. The noise from both cancerous and non-cancerous cultures shows
correlations on many time scales, but these correlations are stronger for the
non-cancerous cells.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 15:32:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lovelady",
"D. C.",
""
],
[
"Richmond",
"T. C.",
""
],
[
"Maggi",
"A. N.",
""
],
[
"Lo",
"C. -M.",
""
],
[
"Rabson",
"D. A.",
""
]
] |
0707.4245 | Ivan Chipchakov Delchev | I. D. Chipchakov | On the Brauer groups of quasilocal fields and the norm groups of their
finite Galois extensions | 30 pages. TYpos corrected | null | null | null | math.RA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper shows that divisible abelian torsion groups are realizable as
Brauer groups of quasilocal fields. It describes the isomorphism classes of
Brauer groups of primarily quasilocal fields and solves the analogous problem
concerning the reduced components of the Brauer groups of two basic types of
Henselian valued absolutely stable fields. For a quasilocal field E and a
finite separable extension R/E, we find two sufficient conditions for validity
of the norm group equality $N(R/E) = N(R_{0}/E)$, where R_{0} is the maximal
abelian extension of E in R. This is used for deriving information on the
arising specific relations between Galois groups and norm groups of finite
Galois extensions of E.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 15:59:25 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 18:30:32 GMT"
},
{
"version": "v3",
"created": "Fri, 23 Nov 2007 16:35:16 GMT"
},
{
"version": "v4",
"created": "Sun, 15 Jun 2008 10:45:15 GMT"
},
{
"version": "v5",
"created": "Tue, 23 Dec 2008 09:37:08 GMT"
},
{
"version": "v6",
"created": "Fri, 6 Feb 2009 12:47:58 GMT"
}
] | 2009-02-06T00:00:00 | [
[
"Chipchakov",
"I. D.",
""
]
] |
0707.4246 | Pietro Antonio Grassi | R. Catenacci, M. Debernardi, P.A. Grassi, and D. Matessi | Balanced Superprojective Varieties | 24 pages, Latex, no figures | null | null | DISTA-2007 | math-ph hep-th math.MP | null | We first review the definition of superprojective spaces from the
functor-of-points perspective. We derive the relation between superprojective
spaces and supercosets in the framework of the theory of sheaves. As an
application of the geometry of superprojective spaces, we extend Donaldson's
definition of balanced manifolds to supermanifolds and we derive the new
conditions of a balanced supermanifold. We apply the construction to
superpoints viewed as submanifolds of superprojective spaces. We conclude with
a list of open issues and interesting problems that can be addressed in the
present context.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 16:22:37 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Catenacci",
"R.",
""
],
[
"Debernardi",
"M.",
""
],
[
"Grassi",
"P. A.",
""
],
[
"Matessi",
"D.",
""
]
] |
0707.4247 | Nicola Bartolo | Daniele Bertacca, Nicola Bartolo (Physics Dept., and INFN, Padova,
Italy) | ISW effect in Unified Dark Matter Scalar Field Cosmologies: an
analytical approach | 15 pages, LateX file; one comment after Eq.(36) and formula (44)
added in order to underline procedure and main results. Accepted for
publication in JCAP; some typos corrected | JCAP0711:026,2007 | 10.1088/1475-7516/2007/11/026 | null | astro-ph gr-qc hep-ph hep-th | null | We perform an analytical study of the Integrated Sachs-Wolfe (ISW) effect
within the framework of Unified Dark Matter models based on a scalar field
which aim at a unified description of dark energy and dark matter. Computing
the temperature power spectrum of the Cosmic Microwave Background anisotropies
we are able to isolate those contributions that can potentially lead to strong
deviations from the usual ISW effect occurring in a $\Lambda$CDM universe. This
helps to highlight the crucial role played by the sound speed in the Unified
Dark Matter models. Our treatment is completely general in that all the results
depend only on the speed of sound of the dark component and thus it can be
applied to a variety of unified models, including those which are not described
by a scalar field but relies on a single dark fluid.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 16:26:20 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Nov 2007 14:35:17 GMT"
},
{
"version": "v3",
"created": "Wed, 13 Feb 2008 18:12:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bertacca",
"Daniele",
"",
"Physics Dept., and INFN, Padova,\n Italy"
],
[
"Bartolo",
"Nicola",
"",
"Physics Dept., and INFN, Padova,\n Italy"
]
] |
0707.4248 | Tobias Stauber | T. Stauber and N. M. R. Peres | Effect of Holstein phonons on the electronic properties of graphene | 13 pages, 4 figures | J. Phys.: Condens. Matter 20, 055002 (2008) | 10.1088/0953-8984/20/5/055002 | null | cond-mat.mes-hall | null | We obtain the self-energy of the electronic propagator due to the presence of
Holstein polarons within the first Born approximation. This leads to a
renormalization of the Fermi velocity of one percent. We further compute the
optical conductivity of the system at the Dirac point and at finite doping
within the Kubo-formula. We argue that the effects due to Holstein phonons are
negligible and that the Boltzmann approach which does not include inter-band
transition and can thus not treat optical phonons due to their high energy of
$\hbar\omega_0\sim0.1-0.2$eV, remains valid.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 17:13:16 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Jan 2008 15:16:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stauber",
"T.",
""
],
[
"Peres",
"N. M. R.",
""
]
] |
0707.4249 | Kumiko Hayashi | Kumiko Hayashi and Mitsunori Takano | Temperature of a Hamiltonian system given as the effective temperature
of a non-equilibrium steady state Langevin thermostat | 4 pages, to appear Phys. Rev. E (Rapid Communications) | Phys. Rev. E 76, 050104 (2007) | 10.1103/PhysRevE.76.050104 | null | cond-mat.stat-mech | null | In non-equilibrium steady states (NESS) far from equilibrium, it is known
that the Einstein relation is violated. Then, the ratio of the diffusion
coefficient to the mobility is called an effective temperature, and the
physical relevance of this effective temperature has been studied in several
works. Although the physical relevance is not yet completely clear, it has been
found that the role of an effective temperature in NESS is indeed analogous to
that of the temperature in equilibrium systems in a number of respects. In this
paper, we find further evidence establishing this analogy. We employ a
non-equilibrium Langevin system as a thermostat for a Hamiltonian system and
find that the kinetic temperature of this Hamiltonian system is equal to the
effective temperature of the thermostat.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 17:18:17 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Oct 2007 18:02:44 GMT"
},
{
"version": "v3",
"created": "Wed, 7 Nov 2007 14:58:57 GMT"
}
] | 2007-12-26T00:00:00 | [
[
"Hayashi",
"Kumiko",
""
],
[
"Takano",
"Mitsunori",
""
]
] |
0707.4250 | Aron Bernstein | A.M. Bernstein | Opening Remarks at Chiral Dynamics 2006:Experimental Tests of Chiral
Symmetry Breaking | 15 pages, 4 figures, slightly revised and corrected version | null | null | null | hep-ph | null | A physical introduction to the basics of chiral dynamics is presented.
Emphasis is placed on experimental tests which have generally demonstrated a
strong confirmation of the predictions of chiral perturbation theory, a low
energy effective field theory of QCD. Special attention is paid to a few cases
where discrepancies exist, requiring further work. Some desirable future tests
are also recommended.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 17:54:40 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Oct 2007 21:25:26 GMT"
}
] | 2007-10-22T00:00:00 | [
[
"Bernstein",
"A. M.",
""
]
] |
0707.4251 | Mircea Neagu | Mircea Neagu | Jet Geometrical Objects Produced by Linear ODEs Systems and Superior
Order ODEs | 16 pages | Studia Universitatis Babes-Bolyai Mathematica, Vol. LVI, No. 1
(2011), 85-99 | null | null | math.DG math.DS | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The aim of this paper is to construct a Riemann-Lagrange geometry on 1-jet
spaces, in the sense of d-connections, d-torsions, d-curvatures,
electromagnetic d-field and geometric electromagnetic Yang-Mills energy,
starting from a given linear ODEs system or a given superior order ODE. The
case of a non-homogenous linear ODE of superior order is disscused.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 17:55:05 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Jul 2009 16:54:00 GMT"
}
] | 2011-02-17T00:00:00 | [
[
"Neagu",
"Mircea",
""
]
] |
0707.4252 | Simon Schuler | S.C. Schuler (NOAO/Ctio), K. Cunha (NOAO), V.V. Smith (NOAO), T.
Sivarani (MSU), T.C. Beers (MSU), Y.S. Lee (MSU) | Fluorine in a Carbon-Enhanced Metal-Poor Star | 13 pages, 3 figures; Accepted for publication in ApJ Letters | AIPConf.Proc.990:192-196,2008 | 10.1063/1.2905539 | null | astro-ph | null | The fluorine abundance of the Carbon-Enhanced Metal-Poor (CEMP) star HE
1305+0132 has been derived by analysis of the molecular HF (1-0) R9 line at
2.3357 microns in a high-resolution (R = 50,000) spectrum obtained with the
Phoenix spectrometer and Gemini-South telescope. Our abundance analysis makes
use of a CNO-enhanced ATLAS12 model atmosphere characterized by a metallicity
and CNO enhancements determined utilizing medium-resolution (R = 3,000) optical
and near-IR spectra. The effective iron abundance is found to be [Fe/H] = -2.5,
making HE 1305+0132 the most Fe-deficient star, by more than an order of
magnitude, for which the abundance of fluorine has been measured. Using
spectral synthesis, we derive a super-solar fluorine abundance of A(19F) = 4.96
+/- 0.21, corresponding to a relative abundance of [F/Fe] = 2.90. A single line
of the Phillips C_2 system is identified in our Phoenix spectrum, and along
with multiple lines of the first-overtone vibration-rotation CO (3-1) band
head, C and O abundances of A(12C) = 8.57 +/- 0.11 and A(16O) = 7.04 +/- 0.14
are derived. We consider the striking fluorine overabundance in the framework
of the nucleosynthetic processes thought to be responsible for the
C-enhancement of CEMP stars and conclude that the atmosphere of HE 1305+0132
was polluted via mass transfer by a primary companion during its asymptotic
giant branch phase. This is the first study of fluorine in a CEMP star, and it
demonstrates that this rare nuclide can be a key diagnostic of nucleosynthetic
processes in the early Galaxy.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 18:12:11 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 16:34:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Schuler",
"S. C.",
"",
"NOAO/Ctio"
],
[
"Cunha",
"K.",
"",
"NOAO"
],
[
"Smith",
"V. V.",
"",
"NOAO"
],
[
"Sivarani",
"T.",
"",
"MSU"
],
[
"Beers",
"T. C.",
"",
"MSU"
],
[
"Lee",
"Y. S.",
"",
"MSU"
]
] |
0707.4253 | Mathieu Sti\'enon | Camille Laurent-Gengoux, Mathieu Stienon and Ping Xu | Holomorphic Poisson Manifolds and Holomorphic Lie Algebroids | 29 pages, v2: paper split into two, part 1 of 2, v3: two references
added, v4: final version to appear in International Mathematics Research
Notices | International Mathematics Research Notices (2008) Vol. 2008 :
article ID rnn088, 46 pages | 10.1093/imrn/rnn088 | null | math.DG hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study holomorphic Poisson manifolds and holomorphic Lie algebroids from
the viewpoint of real Poisson geometry. We give a characterization of
holomorphic Poisson structures in terms of the Poisson Nijenhuis structures of
Magri-Morosi and describe a double complex which computes the holomorphic
Poisson cohomology. A holomorphic Lie algebroid structure on a vector bundle
$A\to X$ is shown to be equivalent to a matched pair of complex Lie algebroids
$(T^{0,1}X,A^{1,0})$, in the sense of Lu. The holomorphic Lie algebroid
cohomology of $A$ is isomorphic to the cohomology of the elliptic Lie algebroid
$T^{0,1}X\bowtie A^{1,0}$. In the case when $(X,\pi)$ is a holomorphic Poisson
manifold and $A=(T^*X)_\pi$, such an elliptic Lie algebroid coincides with the
Dirac structure corresponding to the associated generalized complex structure
of the holomorphic Poisson manifold.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 18:28:39 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Mar 2008 17:55:50 GMT"
},
{
"version": "v3",
"created": "Mon, 17 Mar 2008 19:25:34 GMT"
},
{
"version": "v4",
"created": "Mon, 14 Jul 2008 04:00:28 GMT"
}
] | 2008-10-03T00:00:00 | [
[
"Laurent-Gengoux",
"Camille",
""
],
[
"Stienon",
"Mathieu",
""
],
[
"Xu",
"Ping",
""
]
] |
0707.4254 | Radu Roiban | M. Kruczenski, R. Roiban, A. Tirziu, A.A. Tseytlin | Strong-coupling expansion of cusp anomaly and gluon amplitudes from
quantum open strings in AdS_5 x S^5 | 35 pages. v2: minor corrections, references added | Nucl.Phys.B791:93-124,2008 | 10.1016/j.nuclphysb.2007.09.005 | IMPERIAL-TP-AT-2007-2 | hep-th | null | An important ``observable'' of planar N=4 SYM theory is the scaling function
f(lambda) that appears in the anomalous dimension of large spin twist 2
operators and also in the cusp anomaly of light-like Wilson loops. The
non-trivial relation between the anomalous dimension and the Wilson
interpretations of f(lambda) is well-understood on the perturbative gauge
theory side of the AdS/CFT duality. In the first part of this paper we present
the dual string-theory counterpart of this relation, to all orders in
lambda^(-1/2) expansion. As a check, we explicitly compute the leading 1-loop
string sigma model correction to the cusp Wilson loop, reproducing the same
subleading coefficient in f(lambda) as found earlier in the spinning closed
string case. The same function f(lambda) appears also in the resummed form of
the 4-gluon amplitude as discussed at weak coupling by Bern, Dixon and Smirnov
and recently found at the leading order at strong coupling by Alday and
Maldacena (AM). Here we attempt to extend this approach to subleading order in
lambda^(-1/2) by computing the IR singular part of 1-loop string correction to
the corresponding T-dual Wilson loop. We discuss explicitly the 1-cusp case and
comment on apparent problems with the dimensional regularization proposal of AM
when directly applied order by order in strong coupling (inverse string
tension) expansion.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 18:34:04 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 12:56:23 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kruczenski",
"M.",
""
],
[
"Roiban",
"R.",
""
],
[
"Tirziu",
"A.",
""
],
[
"Tseytlin",
"A. A.",
""
]
] |
0707.4255 | Iddo Tzameret | Nachum Dershowitz and Iddo Tzameret | Complexity of Propositional Proofs under a Promise | 32 pages; a preliminary version appeared in the Proceedings of
ICALP'07 | ACM Transactions on Computational Logic, 11(3):1-29, 2010; | null | null | cs.CC cs.LO | null | We study -- within the framework of propositional proof complexity -- the
problem of certifying unsatisfiability of CNF formulas under the promise that
any satisfiable formula has many satisfying assignments, where ``many'' stands
for an explicitly specified function $\Lam$ in the number of variables $n$. To
this end, we develop propositional proof systems under different measures of
promises (that is, different $\Lam$) as extensions of resolution. This is done
by augmenting resolution with axioms that, roughly, can eliminate sets of truth
assignments defined by Boolean circuits. We then investigate the complexity of
such systems, obtaining an exponential separation in the average-case between
resolution under different size promises:
1. Resolution has polynomial-size refutations for all unsatisfiable 3CNF
formulas when the promise is $\eps\cd2^n$, for any constant $0<\eps<1$.
2. There are no sub-exponential size resolution refutations for random 3CNF
formulas, when the promise is $2^{\delta n}$ (and the number of clauses is
$o(n^{3/2})$), for any constant $0<\delta<1$.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 18:36:01 GMT"
}
] | 2010-04-19T00:00:00 | [
[
"Dershowitz",
"Nachum",
""
],
[
"Tzameret",
"Iddo",
""
]
] |
0707.4256 | Christopher Belford | Christopher Belford (Northern Arizona University), Nandor Sieben
(Northern Arizona University) | Rubbling and Optimal Rubbling of Graphs | 14 pages | null | null | null | math.CO | null | A pebbling move on a graph removes two pebbles at a vertex and adds one
pebble at an adjacent vertex. Rubbling is a version of pebbling where an
additional move is allowed. In this new move one pebble is removed at vertices
v and w adjacent to a vertex u and an extra pebble is added at vertex u. A
vertex is reachable from a pebble distribution if it is possible to move a
pebble to that vertex using rubbling moves. The rubbling number of a graph is
the smallest number m needed to guarantee that any vertex is reachable from any
pebble distribution of m pebbles. The optimal rubbling number is the smallest
number m needed to guarantee a pebble distribution of m pebbles from which any
vertex is reachable. We determine the rubbling and optimal rubbling number of
some families of graphs including cycles.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 19:32:08 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Belford",
"Christopher",
"",
"Northern Arizona University"
],
[
"Sieben",
"Nandor",
"",
"Northern Arizona University"
]
] |
0707.4257 | Gennadi Sardanashvily | G. Sardanashvily | Axiomatic quantum field theory. Jet formalism | 29 pages | null | null | null | hep-th math-ph math.MP | null | Jet formalism provides the adequate mathematical formulation of classical
field theory, reviewed in hep-th/0612182v1. A formulation of QFT compatible
with this classical one is discussed. We are based on the fact that an algebra
of Euclidean quantum fields is graded commutative, and there are homomorphisms
of the graded commutative algebra of classical fields to this algebra. As a
result, any variational symmetry of a classical Lagrangian yields the
identities which Euclidean Green functions of quantum fields satisfy.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 19:55:49 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Sardanashvily",
"G.",
""
]
] |
0707.4258 | Joseph O'Rourke | Jin-ichi Itoh, Joseph O'Rourke, Costin V\^ilcu | Star Unfolding Convex Polyhedra via Quasigeodesic Loops | 10 pages, 7 figures. v2 improves the description of cut locus, and
adds references. v3 improves two figures and their captions. New version v4
offers a completely different proof of non-overlap in the quasigeodesic loop
case, and contains several other substantive improvements. This version is 23
pages long, with 15 figures | null | null | Smith College Computer Science Technical Report 084 | cs.CG cs.DM | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We extend the notion of star unfolding to be based on a quasigeodesic loop Q
rather than on a point. This gives a new general method to unfold the surface
of any convex polyhedron P to a simple (non-overlapping), planar polygon: cut
along one shortest path from each vertex of P to Q, and cut all but one segment
of Q.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 20:02:05 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 20:09:50 GMT"
},
{
"version": "v3",
"created": "Mon, 8 Oct 2007 17:40:06 GMT"
},
{
"version": "v4",
"created": "Wed, 24 Jun 2009 17:18:46 GMT"
}
] | 2009-06-24T00:00:00 | [
[
"Itoh",
"Jin-ichi",
""
],
[
"O'Rourke",
"Joseph",
""
],
[
"Vîlcu",
"Costin",
""
]
] |
0707.4259 | Boris Svistunov | Nikolay Prokof'ev and Boris Svistunov | Fermi-Polaron: Diagrammatic Monte Carlo for Divergent Sign-Alternating
Series | 4 pages, 7 figures | null | 10.1103/PhysRevB.77.020408 | null | cond-mat.stat-mech | null | Diagrammatic Monte Carlo approach is applied to a problem of a single
spin-down fermion resonantly interacting with the sea of ideal spin-up
fermions. On one hand, we develop a generic, sign-problem tolerant, method of
exact numerical solution of polaron-type models. On the other hand, our
solution is important for understanding the phase diagram and properties of the
BCS-BEC crossover in the strongly imbalanced regime. This is the first, and
possibly characteristic, example of how the Monte Carlo approach can be applied
to a divergent sign-alternating diagrammatic series.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 20:04:56 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 18:04:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Prokof'ev",
"Nikolay",
""
],
[
"Svistunov",
"Boris",
""
]
] |
0707.4260 | Giovanni Federico Gronchi | Andrea Milani, Giovanni F. Gronchi, Davide Farnocchia, Zoran Knezevic,
Robert Jedicke, Larry Denneau, Francesco Pierfederici | Orbit Determination with Topocentric Correction: Algorithms for the Next
Generation Surveys | 38 pages, 8 figures | null | null | 4.133.1664 | astro-ph | null | Given a set of astrometric observations of the same object, the problem of
orbit determination is to compute the orbit and to assess its uncertainty and
reliability. For the next generation surveys, with much larger number density
of observed objects, new algorithms or substantial revisions of the classical
ones are needed. The problem has three main steps, preliminary orbit, least
squares orbit, and quality control. The classical theory of preliminary orbits
was incomplete: the consequences of the topocentric correction had not been
fully studied. We show that it is possible to account for this correction,
possibly with an increase in the number of preliminary solutions, without
impairing the overall orbit determination performance. We have developed
modified least squares orbit determination algorithms that can be used to
improve the reliability of the procedure. We have tested the complete procedure
on two simulations with number densities comparable to that expected from the
next generation surveys such as Pan-STARRS and LSST. To control the problem of
false identifications we have introduced a quality control on the fit residuals
based on an array of metrics and a procedure to remove duplications and
contradictions in the output. The results confirm that large sets of
discoveries can be obtained with good quality orbits and very high success rate
losing only 0.6 to 1.3% of objects and a false identification rate in the range
0.02 to 0.06%.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 20:39:14 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Milani",
"Andrea",
""
],
[
"Gronchi",
"Giovanni F.",
""
],
[
"Farnocchia",
"Davide",
""
],
[
"Knezevic",
"Zoran",
""
],
[
"Jedicke",
"Robert",
""
],
[
"Denneau",
"Larry",
""
],
[
"Pierfederici",
"Francesco",
""
]
] |
0707.4261 | David Fithian | David Fithian | Congruence obstructions to pseudomodularity of Fricke groups | 4 pages | null | null | null | math.NT | null | A pseudomodular group is a finite coarea nonarithmetic Fuchsian group whose
cusp set is exactly $\mathbb{P}^1(\mathbb{Q})$. Long and Reid constructed
finitely many of these by considering Fricke groups, i.e., those that
uniformize one-cusped tori. We prove that a zonal Fricke group with rational
cusps is pseudomodular if and only if its cusp set is dense in the finite
adeles of $\mathbb{Q}$. We then deduce that infinitely many such Fricke groups
are not pseudomodular.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:35:28 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 05:55:14 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Fithian",
"David",
""
]
] |
0707.4262 | Martin Greiter | Darrell F. Schroeter, Eliot Kapit, Ronny Thomale, Martin Greiter | Spin Hamiltonian for which the Chiral Spin Liquid is the Exact Ground
State | 5 pages, no figures | Phys. Rev. Lett. 99, 097202 (2007) | 10.1103/PhysRevLett.99.097202 | null | cond-mat.str-el cond-mat.mes-hall | null | We construct a Hamiltonian that singles out the chiral spin liquid on a
square lattice with periodic boundary conditions as the exact and, apart from
the two-fold topological degeneracy, unique ground state.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:37:06 GMT"
}
] | 2007-09-11T00:00:00 | [
[
"Schroeter",
"Darrell F.",
""
],
[
"Kapit",
"Eliot",
""
],
[
"Thomale",
"Ronny",
""
],
[
"Greiter",
"Martin",
""
]
] |
0707.4263 | Salvatore Torquato | S. Torquato and F. H. Stillinger | Toward the Jamming Threshold of Sphere Packings: Tunneled Crystals | 19 pages, 5 figures | null | 10.1063/1.2802184 | null | cond-mat.soft cond-mat.stat-mech | null | We have discovered a new family of three-dimensional crystal sphere packings
that are strictly jammed (i.e., mechanically stable) and yet possess an
anomalously low density. This family constitutes an uncountably infinite number
of crystal packings that are subpackings of the densest crystal packings and
are characterized by a high concentration of self-avoiding "tunnels" (chains of
vacancies) that permeate the structures. The fundamental geometric
characteristics of these tunneled crystals command interest in their own right
and are described here in some detail. These include the lattice vectors (that
specify the packing configurations), coordination structure, Voronoi cells, and
density fluctuations. The tunneled crystals are not only candidate structures
for achieving the jamming threshold (lowest-density rigid packing), but may
have substantially broader significance for condensed matter physics and
materials science.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:39:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Torquato",
"S.",
""
],
[
"Stillinger",
"F. H.",
""
]
] |
0707.4264 | Philippe Sindzingre | P. Sindzingre | Thermodynamic properties of the Spin-1/2 Heisenberg Antiferromagnet with
Anisotropic Exchange on the Kagome Lattice: Comparison with Volborthite | 7 pages, 5 figures | null | null | null | cond-mat.str-el | null | Thermodynamic properties such as magnetic susceptibility and specific heat
have been computed for the Heisenberg Antiferromagnet with spatially
anisotropic exchange on the kagome lattice on clusters up to N=24 spins from
the full spectra obtained by exact diagonalization. This approach is shown to
provide a good represention of these thermodynamic properties above
temperatures of about $J_{\rm av}/5$ where $J_{\rm av}$ is an average of the
coupling constants. Comparison with experimental Volborthite data obtained by
Hiroi {\it {et al}} [J. Phys. Soc. Jpn. {\bf 70},3377 (2001)] shows that
Volborthite is best described by a model with nearly isotropic exchanges in
spite of the significant distortion of the kagom\'{e} lattice of magnetic sites
in this compound and suggests that additional interactions are present.
Comparison of the specific heat at low temperature raise the possibility that
the density of states at low energy in Volborthite might be much lower than in
the Heisenberg model. Magnetization curves under an applied field of the model
are also investigated. The M=1/3 plateau is found to subsist in the anisotropic
case and extend to lower field with increased anisotropy. For sufficient
anisotropy, this plateau would then be observable for a field reasonably
accessible to experiment. The absence of a plateau well below $\sim$ 70 Teslas
would further support a nearly isotropic model.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:49:35 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Sindzingre",
"P.",
""
]
] |
0707.4265 | Rapha\"el Ponge | Raphael Ponge (University of Toronto) | Traces on pseudodifferential operators and sums of commutators | References added, typos fixed. To appear in J. Anal. Math.. 22 pages | J. Anal. Math. 110 (2010) 1-30 | null | null | math.AP math.OA | null | The aim of this paper is to show that various known characterizations of
traces on classical pseudodifferentials operators (PsiDOs) can actually be
obtained by very elementary considerations on PsiDOs, using only basic
properties of these operators. Thereby, we give a unified treatment of the
determinations of the space of traces (i) on PsiDOs of noninteger orders or of
regular parity-class, (ii) on integer order PsiDOs, (iii) on nonpositive order
PsiDOs in dimension greather than or equal to 2, and (iv) on nonpositive order
PsiDOs in dimension 1.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:53:11 GMT"
},
{
"version": "v2",
"created": "Tue, 8 Jan 2008 03:40:26 GMT"
}
] | 2010-09-17T00:00:00 | [
[
"Ponge",
"Raphael",
"",
"University of Toronto"
]
] |
0707.4266 | Erasmo Ferreira | Erasmo Ferreira and Javier Sesma | Representation of Integral Dispersion Relations by Local Forms | 27 pages, 5 figures Few changes in text and in references To be
published in Journal of Mathematical Physics | J.Math.Phys.49:033504,2008 | 10.1063/1.2840912 | null | hep-ph | null | The representation of the usual integral dispersion relations (IDR) of
scattering theory through series of derivatives of the amplitudes is discussed,
extended, simplified, and confirmed as mathematical identities. Forms of
derivative dispersion relations (DDR) valid for the whole energy interval,
recently obtained and presented as double infinite series, are simplified
through the use of new sum rules of the incomplete $\Gamma$ functions, being
reduced to single summations, where the usual convergence criteria are easily
applied. For the forms of the imaginary amplitude used in phenomenology of
hadronic scattering, we show that expressions for the DDR can represent, with
absolute accuracy, the IDR of scattering theory, as true mathematical
identities. Besides the fact that the algebraic manipulation can be easily
understood, numerical examples show the accuracy of these representations up to
the maximum available machine precision. As consequence of our work, it is
concluded that the standard simplified forms sDDR, originally intended for the
high energy limits, are an inconvenient and incomplete separation of terms of
the full expression, leading to wrong evaluations. Since the correspondence
between IDR and the DDR expansions is linear, our results have wide
applicability, covering more general functions, built as combinations of well
studied basic forms.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 21:56:59 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jan 2008 15:34:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ferreira",
"Erasmo",
""
],
[
"Sesma",
"Javier",
""
]
] |
0707.4267 | Sarah Mason | Sarah Mason | An Explicit Construction of Type A Demazure Atoms | 15 pages; final version | Journal of Algebraic Combinatorics, Vol. 29, (2009), No. 3,
p.295--313 | null | null | math.CO math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Demazure characters of type A, which are equivalent to key polynomials, have
been decomposed by Lascoux and Sch\"{u}tzenberger into standard bases. We prove
that the resulting polynomials, which we call Demazure atoms, can be obtained
from a certain specialization of nonsymmetric Macdonald polynomials. This
combinatorial interpretation for Demazure atoms accelerates the computation of
the right key associated to a semi-standard Young tableau. Utilizing a related
construction, we provide a new combinatorial description for the key
polynomials.
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 23:19:43 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Apr 2009 15:28:37 GMT"
}
] | 2009-04-02T00:00:00 | [
[
"Mason",
"Sarah",
""
]
] |
0707.4268 | Guillermo Torres | G. Torres (1), G. A. Bakos (1,2), G. Kovacs (3), D. W. Latham (1), J.
M. Fernandez (1), R. W. Noyes (1), G. A. Esquerdo (1), A. Sozzetti (1,4), D.
A. Fischer (5), R. P. Butler (6), G. W. Marcy (7), R. P. Stefanik (1), D. D.
Sasselov (1), J. Lazar (8), I. Papp (8), and P. Sari (8)
((1)Harvard-Smithsonian Center for Astrophysics; (2) Hubble Fellow; (3)
Konkoly Observatory, Hungary; (4) INAF - Osservatorio Astronomico di Torino,
Italy; (5) San Francisco State University; (6) Carnegie Institute of
Washington; (7) University of California, Berkeley; (8) Hungarian
Astronomical Association, Hungary) | HAT-P-3b: A heavy-element rich planet transiting a K dwarf star | To appear in ApJL | Astrophys.J.666:L121-L124,2007 | 10.1086/521792 | null | astro-ph | null | We report the discovery of a Jupiter-size planet transiting a relatively
bright (V = 11.56) and metal-rich early K dwarf star with a period of about 2.9
days. On the basis of follow-up photometry and spectroscopy we determine the
mass and radius of the planet, HAT-P-3b, to be M_p = 0.599 +/- 0.026 M_Jup and
R_p = 0.890 +/- 0.046 R_Jup. The relatively small size of the object for its
mass implies the presence of about 75 Earth masses worth of heavy elements (1/3
of the total mass) based on current theories of irradiated extrasolar giant
planets, similar to the mass of the core inferred for the transiting planet HD
149026b. The bulk density of HAT-P-3b is found to be rho_p = 1.06 +/- 0.17
g/cm^3, and the planet orbits the star at a distance of 0.03894 AU. Ephemerides
for the transit centers are T_c = 2,454,218.7594 +/- 0.0029 + N (2.899703 +/-
0.000054) (HJD).
| [
{
"version": "v1",
"created": "Sat, 28 Jul 2007 23:32:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Torres",
"G.",
""
],
[
"Bakos",
"G. A.",
""
],
[
"Kovacs",
"G.",
""
],
[
"Latham",
"D. W.",
""
],
[
"Fernandez",
"J. M.",
""
],
[
"Noyes",
"R. W.",
""
],
[
"Esquerdo",
"G. A.",
""
],
[
"Sozzetti",
"A.",
""
],
[
"Fischer",
"D. A.",
""
],
[
"Butler",
"R. P.",
""
],
[
"Marcy",
"G. W.",
""
],
[
"Stefanik",
"R. P.",
""
],
[
"Sasselov",
"D. D.",
""
],
[
"Lazar",
"J.",
""
],
[
"Papp",
"I.",
""
],
[
"Sari",
"P.",
""
]
] |
0707.4269 | Terence C. Tao | Terence Tao | Structure and randomness in combinatorics | 13 pages, no figures. FOCS 2007 tutorial notes. Minor corrections | null | null | null | math.CO | null | Combinatorics, like computer science, often has to deal with large objects of
unspecified (or unusable) structure. One powerful way to deal with such an
arbitrary object is to decompose it into more usable components. In particular,
it has proven profitable to decompose such objects into a \emph{structured}
component, a \emph{pseudo-random} component, and a \emph{small} component (i.e.
an error term); in many cases it is the structured component which then
dominates. We illustrate this philosophy in a number of model cases.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 00:47:53 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Aug 2007 21:36:54 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Tao",
"Terence",
""
]
] |
0707.4270 | Dimitrios Tsimpis | C. Kounnas, D. Lust, P.M. Petropoulos and D. Tsimpis | AdS4 flux vacua in type II superstrings and their domain-wall solutions | Acknowledgment replaced | JHEP 0709:051,2007 | 10.1088/1126-6708/2007/09/051 | LPTENS/07/32, LMU-ASC 50/07, MPP-2007-98, CPTH-RR060.0707 | hep-th | null | We investigate the emergence of supersymmetric negative-vacuum-energy ground
states in four dimensions. First, we rely on the analysis of the effective
superpotential, which depends on the background fluxes of the internal
manifold, or equivalently has its origin in the underlying gauged supergravity.
Four-dimensional, supersymmetric anti-de Sitter vacua with all moduli
stabilized appear when appropriate Ramond and Neveu--Schwarz fluxes are
introduced in IIA. Geometric fluxes are not necessary. Then the whole setup is
analyzed from the perspective of the sources, namely D/NS-branes or
Kaluza--Klein monopoles. Orientifold planes are also required for tadpole
cancellation. The solutions found in four dimensions correspond to domain walls
interpolating between AdS4 and flat spacetime. The various consistency
conditions (equations of motion, Bianchi identities and tadpole cancellation
conditions) are always satisfied, albeit with source terms. We also speculate
on the possibility of assigning (formal) entropies to AdS4 flux vacua via the
corresponding dual brane systems.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 13:34:07 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Jul 2007 13:04:08 GMT"
},
{
"version": "v3",
"created": "Fri, 31 Aug 2007 12:09:20 GMT"
},
{
"version": "v4",
"created": "Tue, 5 Feb 2008 09:30:11 GMT"
}
] | 2009-10-07T00:00:00 | [
[
"Kounnas",
"C.",
""
],
[
"Lust",
"D.",
""
],
[
"Petropoulos",
"P. M.",
""
],
[
"Tsimpis",
"D.",
""
]
] |
0707.4271 | Dmitriy Melnikov | D. V. Melnikov, T. Fujisawa, D. G. Austing, S. Tarucha, and J.-P.
Leburton | Many-body excitations in tunneling current spectra of a few-electron
quantum dot | 5 pages, 2 figures | null | 10.1103/PhysRevB.77.165340 | null | cond-mat.mes-hall | null | Inherent asymmetry in the tunneling barriers of few-electron quantum dots
induces intrinsically different tunneling currents for forward and reverse
source-drain biases in the non-linear transport regime. Here we show that in
addition to spin selection rules, overlap matrix elements between many-body
states are crucial for the correct description of tunneling transmission
through quantum dots at large magnetic fields. Signatures of excited
(N-1)-electron states in the transport process through the N-electron system
are clearly identified in the measured transconductances. Our analysis clearly
confirms the validity of single-electron quantum transport theory in quantum
dots.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:38:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Melnikov",
"D. V.",
""
],
[
"Fujisawa",
"T.",
""
],
[
"Austing",
"D. G.",
""
],
[
"Tarucha",
"S.",
""
],
[
"Leburton",
"J. -P.",
""
]
] |
0707.4272 | Xing-Hao Ye | Xing-Hao Ye | Vacuum Fluctuation (1): the Same Basis of the Relativity and the Quantum
Mechanics | 7 pages, 7 figures | null | null | null | physics.gen-ph | null | The aim of this paper is to reveal the deep relationship between matter and
vacuum, and to seek for the same physical basis of the relativity and the
quantum mechanics. In doing this, three postulates of vacuum fluctuation are
proposed first, the basic premises of the relativity and the quantum mechanics
including the velocity limit, the energy-frequency relation and the de Broglie
wavelength expression of any matter particles are deduced then. As
applications, the idea is used to analyze the Compton effect and the
electron-positron annihilation. It is found that the calculation becomes
simple, and the physical meaning gets clear. The simplicity comes from the
power of the three postulates. To illustrate this, the basic conclusions of the
special theory of relativity such as the relations of mass-velocity,
mass-energy, energy-momentum, time dilation and length contraction are further
deduced. In addition, the significance of the investigation of vacuum
fluctuation in the unification of the physical theories is pointed out.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 09:10:32 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 03:52:52 GMT"
},
{
"version": "v3",
"created": "Fri, 9 Nov 2007 03:15:16 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Ye",
"Xing-Hao",
""
]
] |
0707.4273 | Timo Seppalainen | Marton Balazs and Timo Seppalainen | A convexity property of expectations under exponential weights | After completion of this manuscript we learned that our main results
can be obtained as a special case of some propositions in Karlin: Total
Positivity, Vol.1 | null | null | null | math.PR | null | Take a random variable X with some finite exponential moments. Define an
exponentially weighted expectation by E^t(f) = E(e^{tX}f)/E(e^{tX}) for
admissible values of the parameter t. Denote the weighted expectation of X
itself by r(t) = E^t(X), with inverse function t(r). We prove that for a convex
function f the expectation E^{t(r)}(f) is a convex function of the parameter r.
Along the way we develop correlation inequalities for convex functions.
Motivation for this result comes from equilibrium investigations of some
stochastic interacting systems with stationary product distributions. In
particular, convexity of the hydrodynamic flux function follows in some cases.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:56:45 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Nov 2007 10:44:51 GMT"
}
] | 2007-11-07T00:00:00 | [
[
"Balazs",
"Marton",
""
],
[
"Seppalainen",
"Timo",
""
]
] |
0707.4274 | Srihari Keshavamurthy | Srihari Keshavamurthy | On dynamical tunneling and classical resonances | Completely rewritten and expanded version of a previous submission
physics/0410033. 14 pages and 10 figures | J. Chem. Phys. vol 122, 114109 (2005) | 10.1063/1.1881152 | null | nlin.CD | null | This work establishes a firm relationship between classical nonlinear
resonances and the phenomenon of dynamical tunneling. It is shown that the
classical phase space with its hierarchy of resonance islands completely
characterizes dynamical tunneling and explicit forms of the dynamical barriers
can be obtained only by identifying the key resonances. Relationship between
the phase space viewpoint and the quantum mechanical superexchange approach is
discussed in near-integrable and mixed regular-chaotic situations. For
near-integrable systems with sufficient anharmonicity the effect of multiple
resonances {\it i.e.,} resonance-assisted tunneling can be incorporated
approximately. It is also argued that the, presumed, relation of avoided
crossings to nonlinear resonances does not have to be invoked in order to
understand dynamical tunneling. For molecules with low density of states the
resonance-assisted mechanism is expected to be dominant.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 05:44:38 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Keshavamurthy",
"Srihari",
""
]
] |
0707.4275 | Aleksandar Ivic | Yann Bugeaud and Aleksandar Ivi\'c | Sums of the error term function in the mean square for $\zeta(s)$ | 14 pages | Monats. Mathematik, 155(2008), 107-118 | null | null | math.NT | null | Sums of the form $\sum_{n\le x}E^k(n) (k\in{\bf N}$ fixed) are investigated,
where $$ E(T) = \int_0^T|\zeta(1/2+it)|^2 dt - T\Bigl(\log {T\over2\pi} +
2\gamma -1\Bigr)$$ is the error term in the mean square formula for
$|\zeta(1/2+it)|$. The emphasis is on the case k=1, which is more difficult
than the corresponding sum for the divisor problem. The analysis requires
bounds for the irrationality measure of ${\rm e}^{2\pi m}$ and for the partial
quotients in its continued fraction expansion.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 06:58:02 GMT"
}
] | 2008-11-06T00:00:00 | [
[
"Bugeaud",
"Yann",
""
],
[
"Ivić",
"Aleksandar",
""
]
] |
0707.4276 | Hannes Jung | Magnus Hansson (Lund University), Hannes Jung (DESY) | Towards precision determination of uPDFs | Contribution to DIS07, Munich, 2007 | null | null | null | hep-ph | null | The unintegrated Parton Density Function of the gluon is obtained from a fit
to dijet production in DIS as measured at HERA. Reasonable descriptions of the
measurements are obtained, and a first attempt to constrain the intrinsic
transverse momentum distribution at small kt is presented
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 07:36:52 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Hansson",
"Magnus",
"",
"Lund University"
],
[
"Jung",
"Hannes",
"",
"DESY"
]
] |
0707.4277 | Ahmet T. Alan | A. T. Alan | Effects of the CP Odd Dipole Operators on Gluino-Squark Production | 7 pages, 2 figures | null | null | null | hep-ph | null | We analyze effects of the CP violating interactions on associated
gluino-squark production in the MSSM at hadron colliders. Depending on the
sparticle masses, the hadronic cross sections can be enhanced up to 9.5 % for a
500 GeV gluino at the LHC energies.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 08:07:33 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Alan",
"A. T.",
""
]
] |
0707.4278 | Thomas Podgorski | Victoria Vitkova, Maud-Alix Mader, Chaouqi Misbah, Thomas Podgorski | Rheology of dilute suspensions of vesicles and red blood cells | 4 pages, 3 figures | null | null | null | cond-mat.soft cond-mat.mtrl-sci | null | We present rheology experiments on dilute solutions of vesicles and red blood
cells (RBC). Varying the viscosity ratio $\lambda$ between internal and
external fluids, the microscopic dynamics of suspended objects can be
qualitatively changed from tank-treading ($tt$) to tumbling ($tb$). We find
that in the tt regime the viscosity $\eta$, decreases when $\lambda$ increases,
in contrast with droplet emulsions and elastic capsule theories which are
sometimes invoked to model RBC dynamics. At a critical $\lambda$ (close to the
tt-tb transition) $\eta$ exhibits a minimum before it increases in the tb
regime. This is consistent with a recent theory for vesicles. This points to
the nontrivial fact that the cytoskeleton in RBC does not alter the qualitative
evolution of $\eta$ and that, as far as rheology is concerned, vesicle models
might be a better description.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 08:19:12 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Vitkova",
"Victoria",
""
],
[
"Mader",
"Maud-Alix",
""
],
[
"Misbah",
"Chaouqi",
""
],
[
"Podgorski",
"Thomas",
""
]
] |
0707.4279 | Zhuo Li | Xiang-Hua Li, Fang-Jun Lu and Zhuo Li | Non-Thermal X-ray Properties of Rotation Powered Pulsars and Their Wind
Nebulae | 15 pages, 9 figures, 3 Tables, ApJ accepted version. Substantial
revision, especially luminosity uncertainty taken into accounted and one fig
added. Main conclusions unchanged | null | 10.1086/589495 | null | astro-ph | null | We present a statistical study of the non-thermal X-ray emission of 27 young
rotation powered pulsars (RPPs) and 24 pulsar wind nebulae (PWNe) by using the
Chandra and the XMM-Newton observations, which with the high spatial
resolutions enable us to spatially resolve pulsars from their surrounding PWNe.
We obtain the X-ray luminosities and spectra separately for RPPs and PWNe, and
then investigate their distribution and relation to each other as well as the
relation with the pulsar rotational parameters. In the pair-correlation
analysis we find that: (1) the X-ray (2-10 keV) luminosities of both pulsar and
PWN (L_{psr} and L_{pwn}) display a strong correlation with pulsar spin down
power Edot and characteristic age, and the scalings resulting from a simple
linear fit to the data are L_{psr} \propto Edot^{0.92 \pm 0.04} and L_{pwn}
\propto Edot^{1.45 \pm 0.08} (68% confidence level), respectively, however,
both the fits are not statistically acceptable; (2) L_{psr} also shows a
possible weak correlation with pulsar period P and period derivative Pdot,
whereas L_{pwn} manifests a similar weak correlation with Pdot only; (3) The
PWN photon index Gamma_{pwn} is positively correlated with L_{pwn} and
L_{pwn}/Edot. We also found that the PWN X-ray luminosity is typically 1 to 10
times larger than that from the underlying pulsar, and the PWN photon indices
span a range of ~1.5 to ~2. The statistic study of PWN spectral properties
supports the particle wind model in which the X-ray emitting electrons are
accelerated by the termination shock of the wind.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 12:39:24 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Mar 2008 13:59:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Li",
"Xiang-Hua",
""
],
[
"Lu",
"Fang-Jun",
""
],
[
"Li",
"Zhuo",
""
]
] |
0707.4280 | Narayani Choudhury | Prabhatasree Goel, N. Choudhury and S. L. Chaplot | Fast ion diffusion, superionic conductivity and phase transitions of the
nuclear materials UO2 and Li2O | 8 pages, 2 Tables, 5 Figures: J. Phys.: Condensed Matter (In Press) | J. Phys.: Condens. Matter 19, 386239 (2007) | 10.1088/0953-8984/19/38/386239 | null | cond-mat.mtrl-sci cond-mat.other | null | Lattice dynamics and molecular dynamics studies of the oxides UO2 and Li2O in
their normal as well as superionic phase are reported. Lattice dynamics
calculations have been carried out using a shell model in the quasiharmonic
approximation. The calculated elastic constants, phonon frequencies and
specific heat are in good agreement with reported experimental data, which help
validate the interatomic potentials required for undertaking molecular dynamics
simulations. The calculated free energies reveal high pressure fluorite to
cottunite phase transitions at 70 GPa for UO2 and anti-fluorite to
anti-cotunnite phase transformation at 25 GPa for Li2O, in agreement with
reported experiments. Molecular dynamics studies shed important insights into
the mechanisms of diffusion and superionic behavior at high temperatures. The
calculated superionic transition temperature of Li2O is 1000 K, while that of
UO2 is 2300 K.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 09:18:57 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Goel",
"Prabhatasree",
""
],
[
"Choudhury",
"N.",
""
],
[
"Chaplot",
"S. L.",
""
]
] |
0707.4281 | Emma Jin | Emma Y. Jin and Christian M. Reidys | Central and Local Limit Theorems for RNA Structures | 25 pages, 5 figures | null | null | null | math.CO q-bio.QM | null | A k-noncrossing RNA pseudoknot structure is a graph over $\{1,...,n\}$
without 1-arcs, i.e. arcs of the form (i,i+1) and in which there exists no
k-set of mutually intersecting arcs. In particular, RNA secondary structures
are 2-noncrossing RNA structures. In this paper we prove a central and a local
limit theorem for the distribution of the numbers of 3-noncrossing RNA
structures over n nucleotides with exactly h bonds. We will build on the
results of \cite{Reidys:07rna1} and \cite{Reidys:07rna2}, where the generating
function of k-noncrossing RNA pseudoknot structures and the asymptotics for its
coefficients have been derived. The results of this paper explain the findings
on the numbers of arcs of RNA secondary structures obtained by molecular
folding algorithms and predict the distributions for k-noncrossing RNA folding
algorithms which are currently being developed.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 09:27:30 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Aug 2007 03:34:34 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Jin",
"Emma Y.",
""
],
[
"Reidys",
"Christian M.",
""
]
] |
0707.4282 | Dmitri Bykov | D. V. Bykov, A. A. Slavnov | Matrix and vector models in the strong coupling limit | 8 pages | Theor.Math.Phys.155:708-714,2008 | 10.1007/s11232-008-0060-5 | null | hep-th | null | In this paper we consider matrix and vector models in the large N limit ($N
\times N$ matrices and vectors with N^{2} components). For the case of
zero-dimensional model (D=0) it is proved that in the strong coupling limit $g
\to \infty$ statistical sums of both models coincide up to a coefficient. This
is also true for D=1.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 10:09:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bykov",
"D. V.",
""
],
[
"Slavnov",
"A. A.",
""
]
] |
0707.4283 | Anton Tikhonov Valerievich | Anton V. Tikhonov | Voids in the SDSS Galaxy Survey | 26 pages, 18 figures | Astron.Lett.33:499-511,2007 | 10.1134/S1063773707080014 | null | astro-ph | null | Using the method of searching for arbitrary shaped voids in the distribution
of volume-limited samples of galaxies from the DR5 SDSS survey, we have
identified voids and investigated their characteristics and the change in these
characteristics with decreasing Mlim - the upper limit on the absolute
magnitude of the galaxies involved in the construction of voids. The total
volume of the 50 largest voids increases with decreasing Mlim with a break near
Mr* = -20.44 for SDSS galaxies. The mean density contrast in voids increases
with decreasing Mlim also with a weak break near M*. The exponent of the
dependence of the volume of a void on its rank increases significantly with
decreasing Mlim starting from Mlim ~ -20.4 in the characteristic range of
volumes, which reflects the tendency for greater clustering of brighter
galaxies. The galaxies mostly tend to concentrate toward the void boundaries
and to avoid the central void regions. The axial ratios of the ellipsoids
equivalent to the voids are, on average, retained with changing Mlim and
correspond to elongated and nonoblate void shapes, but some of the voids can
change their shape significantly. The void centers show correlations reflecting
the correlations of the galaxy distribution on scales (35-70)/h Mpc. The galaxy
distribution in the identified voids is nonrandom - groups and filaments can be
identified. We have compared the properties of the galaxies in voids and
galaxies in structures identified using the minimum spanning tree. A noticeable
difference is observed in the mean color indices and star formation rates per
unit stellar mass of the galaxies in dense regions (structures) - as expected,
the galaxies in voids are, on average, bluer and have higher log(SFR/M_star).
These tendencies become stronger toward the central void regions.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 14:28:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Tikhonov",
"Anton V.",
""
]
] |
0707.4284 | Sven-Olaf Moch | A.Glazov, S.Moch and K.Nagano | Structure Functions and Low-x | 15 pages, 11 figures. Presented at 15th International Workshop on
Deep-Inelastic Scattering and Related Subjects (DIS2007), Munich, Germany,
16-20 Apr 2007 | null | null | DESY 07-106 | hep-ph | null | We summarize recent experimental and theoretical results, which were reported
in the working group on Structure Functions and Low-x at the DIS 2007 workshop.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 10:56:59 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Glazov",
"A.",
""
],
[
"Moch",
"S.",
""
],
[
"Nagano",
"K.",
""
]
] |
0707.4285 | Alexei Kniazev | A.Y. Kniazev (1,2), S.A. Pustilnik (2), D.B. Zucker (3,4) ((1) SAAO,
South Africa; (2) SAO, Russia; (3) MPIA, Germany; (4) Cambridge, UK) | Spectroscopy of two PN candidates in IC10 | 8 pages, 5 figures, submitted to MNRAS. Some figures were bitmapped
to reduce the size. Full resolution version is available from
http://www.saao.ac.za/~akniazev/pub/PNe_IC10.pdf | null | 10.1111/j.1365-2966.2007.12540.x | null | astro-ph | null | We present the results of the first spectroscopic observations of two
planetary nebula (PN) candidates in the Local Group dwarf irregular galaxy
IC10. Using several spectral classification diagrams we show that the brightest
PN candidate (PN7) is not a PN, but rather a compact HII region consisting of
two components with low electron number densities. After the rejection of this
PN candidate, the IC10 planetary nebula luminosity function cutoff becomes very
close to the standard value. With the compiled spectroscopic data for a large
number of extragalactic PNe, we analyse a series of diagnostic diagrams to
generate quantitative criteria for separating PNe from unresolved HII regions.
We show that, with the help of the diagnostic diagrams and the derived set of
criteria, PNe can be distinguished from HII regions with an efficiency of
~99.6%. With the obtained spectroscopic data we confirm that another, 1.7 mag
fainter PN candidate (PN9) is a genuine PN. We argue that, based on all
currently available PNe data, IC10 is located at a distance 725+63-33 kpc
(distance modulus (m-M) = 24.30+0.18-0.10).
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 11:01:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kniazev",
"A. Y.",
""
],
[
"Pustilnik",
"S. A.",
""
],
[
"Zucker",
"D. B.",
""
]
] |
0707.4286 | Alexander Kaganovich B. | E. I. Guendelman and A. B. Kaganovich | Symmetry Supporting a Transition to Zero Cosmological Constant State | 4 text pages and one page with 2 figures; text slightly improved; a
reference added | null | null | null | hep-th astro-ph gr-qc | null | In a number of previous publications we demonstrated that the Two Measures
Field Theory (TMT) enables to resolve the old cosmological constant (CC)
problem avoiding the Weinberg's no-go CC theorem and together with this TMT
agrees with all tests of the Einstein's general relativity and allows
inflationary scenarios. Analysis performed in the present paper shows that
there exists an intrinsic symmetry of TMT which emerges in the $\Lambda =0$
ground state. This symmetry contains a subgroup of reflections of the metric
$g_{\mu\nu}\to -g_{\mu\nu}$ studied recently by a number of authors as the
symmetry imposing zero CC. We show that realization of this idea in TMT is free
of fine tuning and has no problems typical to other approaches.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 11:09:46 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 12:16:11 GMT"
},
{
"version": "v3",
"created": "Sun, 5 Aug 2007 07:22:12 GMT"
}
] | 2007-08-05T00:00:00 | [
[
"Guendelman",
"E. I.",
""
],
[
"Kaganovich",
"A. B.",
""
]
] |
0707.4287 | Eckart Viehweg | Eckart Viehweg, De-Qi Zhang | Effective Iitaka fibrations | 19 pages, AMSLaTeX. Following suggestions of a referee, we added
several comments and tried to improve the presentation of the results | Journal of Algebraic Geometry, 18 (2009), 711-730 | null | null | math.AG math.CV | null | We show that the M-canonical map of an n-dimensional complex projective
manifold X of Kodaira dimension two is birational to an Iitaka fibration for a
computable positive integer M. M depends on the index b of a general fibre F of
the Iitaka fibration and on the Betti number of the canonical covering of F, In
particular, M is a universal constant if the dimension n is smaller than or
equal to 4.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 14:36:49 GMT"
},
{
"version": "v2",
"created": "Sun, 16 Sep 2007 12:19:55 GMT"
},
{
"version": "v3",
"created": "Sat, 23 Feb 2008 17:36:55 GMT"
}
] | 2018-06-20T00:00:00 | [
[
"Viehweg",
"Eckart",
""
],
[
"Zhang",
"De-Qi",
""
]
] |
0707.4288 | Alexei Kniazev | A. Kniazev (1,2), A. Zijlstra (3), E. Grebel (4), L. Pilyugin (5), S.
Pustilnik (2), P. Vaisanen (1), D. Buckley (1), Y. Hashimoto (1), N. Loaring
(1), E. Romero (1), M. Still (1), E.B. Burgh (6), K. Nordsieck (6) ((1) SAAO,
South Africa; (2) SAO, Russia; (3) University of Manchester, UK; (4)
University of Heidelberg, Germany; (5) MAO, Ukraine; (6) University of
Wisconsin; USA) | The metallicity extremes of the Sagittarius dSph using SALT spectroscopy
of PNe | 14 pages, 4 figures, accepted to MNRAS | null | 10.1111/j.1365-2966.2008.13435.x | null | astro-ph | null | In this work we present the first spectroscopic results obtained with the
Southern African Large Telescope (SALT) telescope during its
perfomance-verification phase. We find that the Sagittarius dwarf spheroidal
galaxy (Sgr) Sgr contains a youngest stellar population with [O/H] -0.2 and age
t>1 Gyr, and an oldest population with [O/H]=-2.0. The values are based on
spectra of two planetary nebulae (PNe), using empirical abundance
determinations. We calculated abundances for O, N, Ne, Ar, S, Cl, Fe, C and He.
We confirm the high abundances of PN StWr2-21 with 12+log(O/H) = 8.57+/-0.02
dex. The other PN studied, BoBn1, is an extraordinary object in that the neon
abundance exceeds that of oxygen. The abundances of S, Ar and Cl in BoBn1 yield
the original stellar metallicity, corresponding to 12+log(O/H) = 6.72+/-0.16
dex which is 1/110 of the solar value. The actual [O/H] is much higher: third
dredge-up enriched the material by a factor of ~12 in oxygen, ~240 in nitrogen
and ~70 in neon. Neon as well as nitrogen and oxygen content may have been
produced in the intershell of low-mass AGB stars. Well defined broad WR lines
are present in the spectrum of StWr2-21 and absent in the spectrum of BoBn1.
This puts the fraction of [WR]-type central PNe stars to 67% for dSph galaxies.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 11:39:59 GMT"
},
{
"version": "v2",
"created": "Thu, 8 May 2008 23:21:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kniazev",
"A.",
""
],
[
"Zijlstra",
"A.",
""
],
[
"Grebel",
"E.",
""
],
[
"Pilyugin",
"L.",
""
],
[
"Pustilnik",
"S.",
""
],
[
"Vaisanen",
"P.",
""
],
[
"Buckley",
"D.",
""
],
[
"Hashimoto",
"Y.",
""
],
[
"Loaring",
"N.",
""
],
[
"Romero",
"E.",
""
],
[
"Still",
"M.",
""
],
[
"Burgh",
"E. B.",
""
],
[
"Nordsieck",
"K.",
""
]
] |
0707.4289 | Sheng Bao | Stephen Gang Wu, Forrest Sheng Bao, Eric You Xu, Yu-Xuan Wang, Yi-Fan
Chang and Qiao-Liang Xiang | A Leaf Recognition Algorithm for Plant Classification Using
Probabilistic Neural Network | 6 pages, 3 figures, 2 tables | null | null | null | cs.AI | null | In this paper, we employ Probabilistic Neural Network (PNN) with image and
data processing techniques to implement a general purpose automated leaf
recognition algorithm. 12 leaf features are extracted and orthogonalized into 5
principal variables which consist the input vector of the PNN. The PNN is
trained by 1800 leaves to classify 32 kinds of plants with an accuracy greater
than 90%. Compared with other approaches, our algorithm is an accurate
artificial intelligence approach which is fast in execution and easy in
implementation.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 12:31:40 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Wu",
"Stephen Gang",
""
],
[
"Bao",
"Forrest Sheng",
""
],
[
"Xu",
"Eric You",
""
],
[
"Wang",
"Yu-Xuan",
""
],
[
"Chang",
"Yi-Fan",
""
],
[
"Xiang",
"Qiao-Liang",
""
]
] |
0707.4290 | Cong Trinh Le | G. -M. Greuel, Cong Trinh Le | On deformations of maps and curve singularities | 19 pages; few remarks, a reference, an item of a corollary added; a
proposition revised. To be published in Manuscripta Mathematica 2008 | null | null | null | math.AG math.AC | null | We study several deformation functors associated to the normalization of a
reduced curve singularity $(X,0) \subset (\c^n,0)$. The main new results are
explicit formulas, in terms of classical invariants of (X,0), for the cotangent
cohomology groups $T^i, i = 0,1,2,$ of these functors. Thus we obtain precise
statements about smoothness and dimension of the corresponding local moduli
spaces. We apply the results to obtain explicit formulas resp. estimates for
the $\hoa{A}_e$-codimension of a parametrized curve singularity, where
$\hoa{A}_e$ denotes the Mather-Wall group of left-right equivalence.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 12:35:43 GMT"
},
{
"version": "v2",
"created": "Fri, 11 Apr 2008 10:38:35 GMT"
},
{
"version": "v3",
"created": "Thu, 29 May 2008 13:14:07 GMT"
}
] | 2008-05-29T00:00:00 | [
[
"Greuel",
"G. -M.",
""
],
[
"Le",
"Cong Trinh",
""
]
] |
0707.4291 | Galina Nie | G. K. Nie (Institute of Nuclear Physics, Tashkent, Uzbekistan) | Specific Density Of Binding Enerfy Of Core In Beta - Stable Nuclei is
2.57 MeV/fm^3 | 8 pages, 2 Postscript figures | null | null | null | nucl-th | null | Recently an alpha-cluster model based on the pn-pair interactions with using
the isospin invariance of nuclear force has been proposed. According to the
model the excess neutron pairs fill out the free space in the core determined
by the difference in the charge and matter radii of the alpha-clusters. Then
the number of excess neutrons in beta-stable nuclei depends on the number of
the core alpha-clusters. In such a representation the specific density of
binding energy of core is the only parameter to fit the experimental binding
energies of beta-stable nuclei and it turned out to be a constant value equal
to 2.57 MeV/fm^3. Knowing the value allows one to estimate the size of a
nucleus from its experimental binding energy.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 14:26:44 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 07:46:57 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Sep 2007 10:38:48 GMT"
}
] | 2007-09-20T00:00:00 | [
[
"Nie",
"G. K.",
"",
"Institute of Nuclear Physics, Tashkent, Uzbekistan"
]
] |
0707.4292 | Ivan Veseli\'c | Ton\'ci Antunovi\'c and Ivan Veseli\'c | Spectral asymptotics of percolation Hamiltonians on amenable Cayley
graphs | Typos (including those found after publication)corrected | Operator Theory: Advances and Applications, Volume 186, pages,
1-29, 2008 | null | null | math.SP math-ph math.GR math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we study spectral properties of adjacency and Laplace operators
on percolation subgraphs of Cayley graphs of amenable, finitely generated
groups. In particular we describe the asymptotic behaviour of the integrated
density of states (spectral distribution function) of these random Hamiltonians
near the spectral minimum.
The first part of the note discusses various aspects of the quantum
percolation model, subsequently we formulate a series of new results, and
finally we outline the strategy used to prove our main theorem.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 13:55:43 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Nov 2008 16:26:28 GMT"
}
] | 2008-11-27T00:00:00 | [
[
"Antunović",
"Tonći",
""
],
[
"Veselić",
"Ivan",
""
]
] |
0707.4293 | Piet Hut | Piet Hut, Shin Mineshige, Douglas C. Heggie and Junichiro Makino | Modeling Dense Stellar Systems | 23 pages, to appear in Prog. Theor. Phys | Prog.Theor.Phys.118:187-209,2007 | 10.1143/PTP.118.187 | null | astro-ph | null | Black holes and neutron stars present extreme forms of matter that cannot be
created as such in a laboratory on Earth. Instead, we have to observe and
analyze the experiments that are ongoing in the Universe. The most telling
observations of black holes and neutron stars come from dense stellar systems,
where stars are crowded close enough to each other to undergo frequent
interactions. It is the interplay between black holes, neutron stars and other
objects in a dense environment that allows us to use observations to draw firm
conclusions about the properties of these extreme forms of matter, through
comparisons with simulations. The art of modeling dense stellar systems through
computer simulations forms the main topic of this review.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 14:17:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hut",
"Piet",
""
],
[
"Mineshige",
"Shin",
""
],
[
"Heggie",
"Douglas C.",
""
],
[
"Makino",
"Junichiro",
""
]
] |
0707.4294 | M. M. Glazov | E. A. Zhukov, D. R. Yakovlev, M. Bayer, M. M. Glazov, E. L. Ivchenko,
G. Karczewski, T. Wojtowicz, J. Kossut | Spin coherence of a two-dimensional electron gas induced by resonant
excitation of trions and excitons in CdTe/(Cd,Mg)Te quantum wells | 18 pages, 20 figures | Phys. Rev. B 76, 205310 (2007) | 10.1103/PhysRevB.76.205310 | null | cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.other | null | The mechanisms for generation of long-lived spin coherence in a
two-dimensional electron gas (2DEG) have been studied experimentally by means
of a picosecond pump-probe Kerr rotation technique. CdTe/(Cd,Mg)Te quantum
wells with a diluted 2DEG were investigated. The strong Coulomb interaction
between electrons and holes, which results in large binding energies of neutral
excitons and negatively charged excitons (trions), allows one to address
selectively the exciton or trion states by resonant optical excitation.
Different scenarios of spin coherence generation were analyzed theoretically,
among them the direct trion photocreation, the formation of trions from
photogenerated excitons and the electron-exciton exchange scattering. Good
agreement between experiment and theory is found.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 14:21:25 GMT"
}
] | 2007-12-01T00:00:00 | [
[
"Zhukov",
"E. A.",
""
],
[
"Yakovlev",
"D. R.",
""
],
[
"Bayer",
"M.",
""
],
[
"Glazov",
"M. M.",
""
],
[
"Ivchenko",
"E. L.",
""
],
[
"Karczewski",
"G.",
""
],
[
"Wojtowicz",
"T.",
""
],
[
"Kossut",
"J.",
""
]
] |
0707.4295 | Pankaj Agrawal | Pankaj Agrawal and B. Pradhan | Task-Oriented Maximally Entangled States | 12 pages, no figures | null | null | null | quant-ph | null | We introduce the notion of a task-oriented maximally entangled state (TMES).
This notion depends on the tasks for which a quantum state is used as the
resource. This concept may be more fruitful than that of a general maximally
entangled state in the case of a multipartite system. We illustrate this idea
by giving an operational definition of maximally entangled states on the basis
of communication tasks of teleportation and superdense coding. We also give
examples and a procedure to obtain such TMESs for {\em n}-qubit systems.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 15:29:59 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 11:54:33 GMT"
}
] | 2007-08-16T00:00:00 | [
[
"Agrawal",
"Pankaj",
""
],
[
"Pradhan",
"B.",
""
]
] |
0707.4296 | Matthias Schindler | M. R. Schindler, D. Djukanovic, J. Gegelia, S. Scherer | Infrared renormalization of two-loop integrals and the chiral expansion
of the nucleon mass | corrected typos in Eqs. (D6) and (D7), results and conclusions
unchanged | Nucl.Phys.A803:68-114,2008 | 10.1016/j.nuclphysa.2008.01.023 | MKPH-T-07-10 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe details of the renormalization of two-loop integrals relevant to
the calculation of the nucleon mass in the framework of manifestly
Lorentz-invariant chiral perturbation theory using infrared renormalization. It
is shown that the renormalization can be performed while preserving all
relevant symmetries, in particular chiral symmetry, and that renormalized
diagrams respect the standard power counting rules. As an application we
calculate the chiral expansion of the nucleon mass to order O(q^6).
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 14:26:57 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Feb 2008 15:22:46 GMT"
},
{
"version": "v3",
"created": "Thu, 25 Feb 2021 16:29:40 GMT"
}
] | 2021-02-26T00:00:00 | [
[
"Schindler",
"M. R.",
""
],
[
"Djukanovic",
"D.",
""
],
[
"Gegelia",
"J.",
""
],
[
"Scherer",
"S.",
""
]
] |
0707.4297 | Alexander Pushnitski | Alexander Pushnitski and Grigori Rozenblum | Eigenvalue clusters of the Landau Hamiltonian in the exterior of a
compact domain | 16 pages, Latex | null | null | null | math.SP math-ph math.MP | null | We consider the Schrodinger operator with a constant magnetic field in the
exterior of a compact domain on the plane. The spectrum of this operator
consists of clusters of eigenvalues around the Landau levels. We discuss the
rate of accumulation of eigenvalues in a fixed cluster.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 15:45:48 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Pushnitski",
"Alexander",
""
],
[
"Rozenblum",
"Grigori",
""
]
] |
0707.4298 | Shlomo Reisner | M. A. Lopez, S. Reisner | A note on equipartition | Some misprints in earlier versions are corrected, one reference is
added with remarks concerning it | null | null | null | cs.CG math.FA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The problem of the existence of an equi-partition of a curve in $\R^n$ has
recently been raised in the context of computational geometry. The problem is
to show that for a (continuous) curve $\Gamma : [0,1] \to \R^n$ and for any
positive integer N, there exist points $t_0=0<t_1<...<t_{N-1}<1=t_N$, such that
$d(\Gamma(t_{i-1}),\Gamma(t_i))=d(\Gamma(t_{i}),\Gamma(t_{i+1}))$ for all
$i=1,...,N$, where d is a metric or even a semi-metric (a weaker notion) on
$\R^n$. We show here that the existence of such points, in a broader context,
is a consequence of Brower's fixed point theorem.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 15:46:53 GMT"
},
{
"version": "v2",
"created": "Tue, 8 Jul 2008 13:28:41 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jul 2008 16:21:55 GMT"
}
] | 2008-07-15T00:00:00 | [
[
"Lopez",
"M. A.",
""
],
[
"Reisner",
"S.",
""
]
] |
0707.4299 | Bart{\l}omiej Siudeja | R. Ba\~nuelos, T. Kulczycki and B. Siudeja | Neumann Heat kernel monotonicity | null | Algebr. Geom. Topol. 8 (2008) 1989-2029 | 10.2140/agt.2008.8.1989 | null | math.PR | null | We prove that the diagonal of the transition probabilities for the
d-dimensional Bessel processes on (0, 1], reflected at 1, which we denote by
$p_R^N(t, r,r)$, is an increasing function of r for d>2 and that this is false
for d=2.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 16:07:37 GMT"
}
] | 2014-10-01T00:00:00 | [
[
"Bañuelos",
"R.",
""
],
[
"Kulczycki",
"T.",
""
],
[
"Siudeja",
"B.",
""
]
] |
0707.4300 | Marc Culler | Marc Culler and Peter B. Shalen | Volume and homology of one-cusped hyperbolic 3-manifolds | 31 pages. This version agrees with the published version of the
paper, except that an error in the published abstract has been corrected. In
particular, the result which applies to manifolds with mod 2 homology of
dimension at least 7 is stronger and has a shorter proof than the
corresponding result in version 2 | Algebr. Geom. Topol. 8 (2008) 343-379 | 10.2140/agt.2008.8.343 | null | math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let M be a complete, finite-volume, orientable hyperbolic manifold having
exactly one cusp. If we assume that pi_1(M) has no subgroup isomorphic to a
genus-2 surface group, and that either (a) H_1(M;Z_p) has dimension at least 5
for some prime p, or (b) H_1(M;Z_2) has dimension at least 4, and the subspace
of H^2(M;Z_2) spanned by the image of the cup product has dimension at most 1,
then vol M > 5.06 If we assume that H_1(M;Z_2) has dimension at least 7, and
that the compact core of M does not contain a genus-2 closed incompressible
surface, then vol M > 5.06.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 16:11:25 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Aug 2007 18:30:56 GMT"
},
{
"version": "v3",
"created": "Tue, 28 Oct 2008 23:59:51 GMT"
}
] | 2014-10-01T00:00:00 | [
[
"Culler",
"Marc",
""
],
[
"Shalen",
"Peter B.",
""
]
] |
0707.4301 | Patryk Sofia Lykawka | Patryk Sofia Lykawka and Tadashi Mukai | Resonance sticking in the scattered disk | 24 pages, 7 figures, 1 table. Accepted for publication in Icarus
(authors minor information fixed) | Icarus 192:238-247,2007 | 10.1016/j.icarus.2007.06.007 | null | astro-ph physics.comp-ph | null | We investigate the dynamical evolution of trans-Neptunian objects (TNOs) in
typical scattered disk orbits (scattered TNOs) by performing simulations using
several thousand particles lying initially on Neptune-encountering orbits. We
explore the role of resonance sticking in the scattered disk, a phenomenon
characterized by multiple temporary resonance captures ('resonances' refers to
external mean motion resonances with Neptune, which can be described in the
form r:s, where the arguments r and s are integers). First, all scattered TNOs
evolve through intermittent temporary resonance capture events and
gravitational scattering by Neptune. Each scattered TNO experiences tens to
hundreds of resonance captures over a period of 4 Gyr, which represents about
38% of the object's lifetime (mean value). Second, resonance sticking plays an
important role at semimajor axes a < 250 AU, where the great majority of such
captures occurred. It is noteworthy that the stickiest (i.e., dominant)
resonances in the scattered disk are located within this distance range and are
those possessing the lowest argument s. This was evinced by r:1, r:2 and r:3
resonances, which played the greatest role during resonance sticking evolution,
often leading to captures in several of their neighboring resonances. Finally,
the timescales and likelihood of temporary resonance captures are roughly
proportional to resonance strength. The dominance of low s resonances is also
related to the latter. In sum, resonance sticking has an important impact on
the evolution of scattered TNOs, contributing significantly to the longevity of
these objects.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 16:32:43 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 08:12:21 GMT"
}
] | 2010-11-11T00:00:00 | [
[
"Lykawka",
"Patryk Sofia",
""
],
[
"Mukai",
"Tadashi",
""
]
] |
0707.4302 | Boris Kopeliovich | B.Z.Kopeliovich, I.K.Potashnikova and Ivan Schmidt | Quenching of high-pT hadrons: Alternative scenario | Talk at the Workshop on Heavy Ion Collisions at the LHC: Last Call
for Predictions, Geneva, Switzerland, 14 May - 8 Jun 2007 | null | null | null | nucl-th hep-ph | null | A new scenario, alternative to energy loss, for the observed suppression of
high-pT hadrons observed at RHIC is proposed. In the limit of a very dense
medium crated in nuclear collisions the mean free-path of the produced
(pre)hadron vanishes, and and the nuclear suppression, R_{AA} is completely
controlled by the production length. The RHIC data are well explained in a
parameter free way, and predictions for LHC are provided.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 17:17:12 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Kopeliovich",
"B. Z.",
""
],
[
"Potashnikova",
"I. K.",
""
],
[
"Schmidt",
"Ivan",
""
]
] |
0707.4303 | Clifford V. Johnson | Clifford V. Johnson | Heterotic Coset Models of Microscopic Strings and Black Holes | 14 pages, v2: typos corrected and references added. Two important
formulae for central charge are corrected. Improved discussion of CFTs for
higher dimensional and AdS cases | null | null | null | hep-th | null | Following a recent conjecture by Lapan, Simons and Strominger, we revisit and
discuss an intrinsically heterotic class of conformal field theories,
emphasizing their Lagrangian construction as asymmetrically gauged WZW models,
which may be useful in several applications to the study of supersymmetric
strings and black holes in heterotic and type II string theory compactified on
T^6 and K3 X T^2 respectively. In these cases, the leading supergravity
geometry is singular, but higher order corrections remove this singularity in a
way that is consistent with, for example the non-zero entropy for the black
holes that these strings form after wrapping on an additional circle. The
conformal field theories have the right structure to capture the features of
the supergravity analysis, and possess precisely the microscopic target spaces
required. We describe in detail the model with AdS_3 X S^2 geometry, which is
conjectured by Lapan et. al. to represent a fundamental heterotic string in
five dimensions, and then propose conformal field theories which are potential
candidates for the microscopic geometry of heterotic strings in $D$ dimensions,
with target space AdS_3 X S^{D-3}. We also discuss some conformal field
theories that give microscopic AdS target spaces in various dimensions.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 17:33:16 GMT"
},
{
"version": "v2",
"created": "Sat, 4 Aug 2007 22:22:00 GMT"
}
] | 2007-08-05T00:00:00 | [
[
"Johnson",
"Clifford V.",
""
]
] |
0707.4304 | Alejandro Vaisman Prof. | Leticia Gomez, Sofie Haesevoets, Bart Kuijpers and Alejandro Vaisman | Spatial Aggregation: Data Model and Implementation | 56 pages, 28 figures | null | null | null | cs.DB | null | Data aggregation in Geographic Information Systems (GIS) is only marginally
present in commercial systems nowadays, mostly through ad-hoc solutions. In
this paper, we first present a formal model for representing spatial data. This
model integrates geographic data and information contained in data warehouses
external to the GIS. We define the notion of geometric aggregation, a general
framework for aggregate queries in a GIS setting. We also identify the class of
summable queries, which can be efficiently evaluated by precomputing the
overlay of two or more of the thematic layers involved in the query. We also
sketch a language, denoted GISOLAP-QL, for expressing queries that involve GIS
and OLAP features. In addition, we introduce Piet, an implementation of our
proposal, that makes use of overlay precomputation for answering spatial
queries (aggregate or not). Our experimental evaluation showed that for a
certain class of geometric queries with or without aggregation, overlay
precomputation outperforms R-tree-based techniques. Finally, as a particular
application of our proposal, we study topological queries.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:46:50 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Gomez",
"Leticia",
""
],
[
"Haesevoets",
"Sofie",
""
],
[
"Kuijpers",
"Bart",
""
],
[
"Vaisman",
"Alejandro",
""
]
] |
0707.4305 | I. Dolgachev | Igor V. Dolgachev and Vasily A. Iskovskikh | On elements of prime order in the plane Cremona group over a perfect
field | 19 pages, essential revision of the previous version | null | null | null | math.AG math.NT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that the plane Cremona group over a perfect field $k$ of
characteristic $p \ge 0$ contains an element of prime order $\ell\ge 7$ not
equal to $p$ if and only if there exists a 2-dimensional algebraic torus $T$
over $k$ such that $T(k)$ contains an element of order $\ell$. If $p = 0$ and
$k$ does not contain a primitive $\ell$-th root of unity, we show that there
are no elements of prime order $\ell > 7$ in $\Cr_2(k)$ and all elements of
order 7 are conjugate.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 17:38:37 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 17:19:33 GMT"
},
{
"version": "v3",
"created": "Mon, 25 Feb 2008 15:07:08 GMT"
},
{
"version": "v4",
"created": "Thu, 10 Jul 2008 01:22:29 GMT"
}
] | 2008-07-10T00:00:00 | [
[
"Dolgachev",
"Igor V.",
""
],
[
"Iskovskikh",
"Vasily A.",
""
]
] |
0707.4306 | Suresh Govindarajan | Aswin K. Balasubramanian (IITM), Suresh Govindarajan (IITM), Chethan
N. Gowdigere (ICTP) | Symplectic potentials and resolved Ricci-flat ACG metrics | LaTeX, 34 pages, 4 figures (v2)presentation improved, typos corrected
and references added (v3)matches published version | Class.Quant.Grav.24:6393-6416,2007 | 10.1088/0264-9381/24/24/014 | IITM/PH/TH/2007/8, IC/2007/059 | hep-th math.DG | null | We pursue the symplectic description of toric Kahler manifolds. There exists
a general local classification of metrics on toric Kahler manifolds equipped
with Hamiltonian two-forms due to Apostolov, Calderbank and Gauduchon(ACG). We
derive the symplectic potential for these metrics. Using a method due to Abreu,
we relate the symplectic potential to the canonical potential written by
Guillemin. This enables us to recover the moment polytope associated with
metrics and we thus obtain global information about the metric. We illustrate
these general considerations by focusing on six-dimensional Ricci flat metrics
and obtain Ricci flat metrics associated with real cones over L^{pqr} and
Y^{pq} manifolds. The metrics associated with cones over Y^{pq} manifolds turn
out to be partially resolved with two blowup parameters taking special
(non-zero)values. For a fixed Y^{pq} manifold, we find explicit metrics for
several inequivalent blow-ups parametrised by a natural number k in the range
0<k<p. We also show that all known examples of resolved metrics such as the
resolved conifold and the resolution of C^3/Z_3 also fit the ACG
classification.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 08:35:46 GMT"
},
{
"version": "v2",
"created": "Sat, 1 Sep 2007 06:10:27 GMT"
},
{
"version": "v3",
"created": "Mon, 3 Dec 2007 11:54:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Balasubramanian",
"Aswin K.",
"",
"IITM"
],
[
"Govindarajan",
"Suresh",
"",
"IITM"
],
[
"Gowdigere",
"Chethan N.",
"",
"ICTP"
]
] |
0707.4307 | Zhiliang Yuan | Z. L. Yuan, B. E. Kardynal, A. W. Sharpe, and A. J. Shields | High speed single photon detection in the near-infrared | null | Appl. Phys. Lett. 91, 041114(2007) | 10.1063/1.2760135 | null | quant-ph physics.ins-det physics.optics | null | InGaAs avalanche photodiodes (APDs) are convenient for single photon
detection in the near-infrared (NIR) including the fibre communication bands
(1.31/1.55 $\mu$m). However, to suppress afterpulse noise due to trapped
avalanche charge, they must be gated with MHz repetition frequencies, thereby
severely limiting the count rate in NIR applications. Here we show gating
frequencies for InGaAs-APDs well beyond 1 GHz. Using a self-differencing
technique to sense much weaker avalanches, we reduce drastically afterpulse
noise. At 1.25 GHz, we obtain a detection efficiency of 10.8% with an
afterpulse probability of 6.16%. In addition, the detector features low jitter
(55 ps) and a count rate of 100 MHz.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 19:41:42 GMT"
}
] | 2008-05-02T00:00:00 | [
[
"Yuan",
"Z. L.",
""
],
[
"Kardynal",
"B. E.",
""
],
[
"Sharpe",
"A. W.",
""
],
[
"Shields",
"A. J.",
""
]
] |
0707.4308 | Merab Gogberashvili Dr | Merab Gogberashvili | A Machian Solution of the Hierarchy Problem | The version accepted by Eur. Phys. J. C | Eur.Phys.J.C54:671-674,2008 | 10.1140/epjc/s10052-008-0559-9 | null | hep-th gr-qc hep-ph | null | The new interpretation of Mach's principle of mass of a particle being a
measure of the interactions of this particle with all other gravitating
particles inside its causal spheres is introduced. It is shown that within some
alternative model of gravitation that incorporates this principle, the Machian
influence of the universe can reduce Planck's scale to the electro-weak scale
and the large number that is needed to explain the hierarchy between the scales
is the amount of gravitating particles inside the universe horizon. Our model
can lead to new observable effects at cosmological distances and close to the
sources of a strong gravitational field.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 19:51:34 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Feb 2008 13:54:25 GMT"
},
{
"version": "v3",
"created": "Thu, 13 Mar 2008 08:30:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gogberashvili",
"Merab",
""
]
] |
0707.4309 | Antonio Delgado | Antonio Delgado, Jose R. Espinosa, and Mariano Quiros | Unparticles-Higgs Interplay | 14 pages, 7 figures, typos corrected | JHEP0710:094,2007 | 10.1088/1126-6708/2007/10/094 | null | hep-ph | null | We show that scalar unparticles coupled to the Standard Model Higgs at the
renormalizable level can have a dramatic impact in the breaking of the
electroweak symmetry already at tree level. In particular one can get the
proper electroweak scale without the need of a Higgs mass term in the
Lagrangian. By studying the mixed unparticle-Higgs propagator and spectral
function we also show how unparticles can shift the Higgs mass away from its
Standard Model value, \lambda v^2, and influence other Higgs boson properties.
Conversely, we study in some detail how electroweak symmetry breaking affects
the unparticle sector by breaking its conformal symmetry and generating a mass
gap. We also show that, for Higgs masses above that gap, unparticles can
increase quite significantly the Higgs width.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 19:21:39 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Aug 2007 12:57:25 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Delgado",
"Antonio",
""
],
[
"Espinosa",
"Jose R.",
""
],
[
"Quiros",
"Mariano",
""
]
] |
0707.4310 | Sandor Kovacs | Carolina Araujo, St\'ephane Druel, S\'andor J. Kov\'acs | Cohomological characterizations of projective spaces and hyperquadrics | Added Lemma 2.8 and slightly changed proof of Lemma 6.2 to make them
apply for torsion-free sheaves and not only to vector bundles | null | 10.1007/s00222-008-0130-1 | null | math.AG | null | We confirm Beauville's conjecture that claims that if the p-th exterior power
of the tangent bundle of a smooth projective variety contains the p-th power of
an ample line bundle, then the variety is either the projective space or the
p-dimensional quadric hypersurface.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 18:30:57 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 08:03:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Araujo",
"Carolina",
""
],
[
"Druel",
"Stéphane",
""
],
[
"Kovács",
"Sándor J.",
""
]
] |
0707.4311 | Sanket Dusad | S. Dusad, S. N. Diggavi and A. R. Calderbank | Embedded Rank Distance Codes for ISI channels | Submitted to IEEE Transactions on Information Theory | null | 10.1109/TIT.2008.929960 | null | cs.IT math.IT | null | Designs for transmit alphabet constrained space-time codes naturally lead to
questions about the design of rank distance codes. Recently, diversity embedded
multi-level space-time codes for flat fading channels have been designed from
sets of binary matrices with rank distance guarantees over the binary field by
mapping them onto QAM and PSK constellations. In this paper we demonstrate that
diversity embedded space-time codes for fading Inter-Symbol Interference (ISI)
channels can be designed with provable rank distance guarantees. As a corollary
we obtain an asymptotic characterization of the fixed transmit alphabet
rate-diversity trade-off for multiple antenna fading ISI channels. The key idea
is to construct and analyze properties of binary matrices with a particular
structure induced by ISI channels.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 20:47:57 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Dusad",
"S.",
""
],
[
"Diggavi",
"S. N.",
""
],
[
"Calderbank",
"A. R.",
""
]
] |
0707.4312 | Oriana Mansutti | Alessandro De Angelis, Marco Roncadelli, Oriana Mansutti | Evidence for a new light spin-zero boson from cosmological gamma-ray
propagation? | 4 pages, 1 figure | Phys.Rev.D76:121301,2007 | 10.1103/PhysRevD.76.121301 | null | astro-ph hep-ex hep-ph | null | Recent findings by Imaging Atmospheric Cherenkov Telescopes indicate a large
transparency of the Universe to gamma rays, which can be hardly explained
within the current models of extragalactic background light. We show that the
observed transparency is naturally produced by an oscillation mechanism --
which can occur inside intergalactic magnetic fields -- whereby a photon can
become a new spin-zero boson with mass m << 10^(-10) eV. Because the latter
particle travels unimpeded throughout the Universe, photons can reach the
observer even if the distance from the source considerably exceeds their mean
free path. We compute the expected flux of gamma rays from blazar 3C279 at
different energies. Our predictions can be tested in the near future by the
gamma-ray telescopes H.E.S.S., MAGIC, CANGAROO and VERITAS. Moreover, our
result provides an important observational test for models of dark energy
wherein quintessence is coupled to the photon through an effective
dimension-five operator.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 16:14:42 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 15:47:51 GMT"
},
{
"version": "v3",
"created": "Wed, 19 Dec 2007 16:16:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"De Angelis",
"Alessandro",
""
],
[
"Roncadelli",
"Marco",
""
],
[
"Mansutti",
"Oriana",
""
]
] |
0707.4313 | Rodrigo Banuelos | Rodrigo Banuelos and Tadeusz Kulczycki | Trace Estimates for Stable Processes | null | null | null | null | math.SP math.PR | null | In this paper we study the behaviour in time of the trace (the partition
function) of the heat semigroup associated with symmetric stable processes in
domains of $\Rd$. In particular, we show that for domains with the so called
{\it{$R$-smoothness}} property the second terms in the asymptotic as $t\to 0$
involves the surface area of the domain, just as in the case of Brownian
motion.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 20:51:26 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Banuelos",
"Rodrigo",
""
],
[
"Kulczycki",
"Tadeusz",
""
]
] |
0707.4314 | Domingo Anibal Garcia-Hernandez Dr. | D. A. Garcia-Hernandez, J. V. Perea-Calderon, M. Bobrowsky,
P.Garcia-Lario | Spitzer/IRS spectroscopy of high mass precursors to planetary nebulae | To appear in The Astrophysical Journal Letters (scheduled in the 2007
September 1 issue) | 2007ApJ...666L..33G | 10.1086/521673 | null | astro-ph | null | We present Spitzer/IRS observations of a small sample of heavily obscured
IRAS sources displaying both the infrared and OH maser emission characteristic
of OH/IR stars on the asymptotic giant branch (AGB), but also radio continuum
emission typical of ionized planetary nebulae (PNe), the so-called OHPNe. Our
observations show that their mid-infrared spectra are dominated by the
simultaneous presence of strong and broad amorphous silicate absorption
features together with crystalline silicate features, originated in their
O-rich circumstellar shells. Out of the five sources observed, three of them
are clearly non-variable at infrared wavelengths, confirming their post-AGB
status, while the remaining two still show strong photometric fluctuations, and
may still have not yet departed from the AGB. One of the non-variable sources
in the sample, IRAS 17393-2727, displays a strong [Ne II] nebular emission at
12.8 microns, indicating that the ionization of its central region has already
started. This suggests a rapid evolution from the AGB to the PN stage. We
propose that these heavily obscured OHPNe represent the population of high mass
precursors to PNe in our Galaxy.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:13:19 GMT"
}
] | 2012-08-10T00:00:00 | [
[
"Garcia-Hernandez",
"D. A.",
""
],
[
"Perea-Calderon",
"J. V.",
""
],
[
"Bobrowsky",
"M.",
""
],
[
"Garcia-Lario",
"P.",
""
]
] |
0707.4315 | Julia Stasi\'nska | Remigiusz Augusiak, Julia Stasi\'nska, Pawel Horodecki | Beyond the standard entropic inequalities: stronger scalar separability
criteria and their applications | 15 Pages, RevTex, 7 figures, some new results were added, few
references changed, typos corrected | Physical Review A 77, 012333 (2008) | 10.1103/PhysRevA.77.012333 | null | quant-ph | null | Recently it was shown that if a given state fulfils the reduction criterion
it must also satisfy the known entropic inequalities. Now the questions arises
whether on the assumption that stronger criteria based on positive but not
completely positive maps are satisfied, it is possible to derive some scalar
inequalities stronger than the entropic ones. In this paper we show that under
some assumptions the extended reduction criterion [H.-P. Breuer, Phys. Rev.
Lett 97, 080501 (2006); W. Hall, J. Phys. A 40, 6183 (2007)] leads to some
entropic--like inequalities which are much stronger than their entropic
counterparts. The comparison of the derived inequalities with other
separability criteria shows that such approach might lead to strong scalar
criteria detecting both distillable and bound entanglement. In particular, in
the case of SO(3)-invariant states it is shown that the present inequalities
detect entanglement in regions in which entanglement witnesses based on
extended reduction map fail. It should be also emphasized that in the case of
$2\otimes N$ states the derived inequalities detect entanglement efficiently,
while the extended reduction maps are useless when acting on the qubit
subsystem. Moreover, there is a natural way to construct a many-copy
entanglement witnesses based on the derived inequalities so, in principle,
there is a possibility of experimental realization. Some open problems and
possibilities for further studies are outlined.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:21:50 GMT"
},
{
"version": "v2",
"created": "Sun, 7 Oct 2007 21:07:29 GMT"
},
{
"version": "v3",
"created": "Tue, 12 Feb 2008 23:17:51 GMT"
}
] | 2008-02-13T00:00:00 | [
[
"Augusiak",
"Remigiusz",
""
],
[
"Stasińska",
"Julia",
""
],
[
"Horodecki",
"Pawel",
""
]
] |
0707.4316 | Christopher Mooney | Christopher Mooney | All CAT(0) Boundaries of a Group of the Form HxK are CE Equivalent | 8 pages, 3 figures | null | null | null | math.GT math.GR | null | M. Bestvina has shown that for any given torsion-free CAT(0) group G, all of
its boundaries are shape equivalent. He then posed the question of whether they
satisfy the stronger condition of being cell-like equivalent. In this article
we prove that the answer is "Yes" in the situation where the group in question
splits as a direct product with infinite factors. We accomplish this by proving
an interesting theorem in shape theory.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:39:07 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Mooney",
"Christopher",
""
]
] |
0707.4317 | Jean-Yves Welschinger | Jean-Yves Welschinger | Optimalit\'e, congruences et calculs d'invariants des vari\'et\'es
symplectiques r\'eelles de dimension quatre | 42 pages, 3 figures | null | null | null | math.SG math.AG | null | This paper follows a previous one in which were introduced deformation
invariants $\chi^d_r$, $d \in H_2 (X ; \Z)$, $r \in \N$, of closed real
symplectic four-manifolds $(X, \omega, c_X)$, invariants which produced lower
bounds in real enumerative geometry. We prove here using methods of symplectic
field theory that the lower bounds are sharp when $r \leq 1$ and the real locus
of the manifold contains a sphere, torus or real projective plane (under
stronger assumptions in this last case). We also prove that a big power of two
divides $\chi^d_r$ as soon as r is not too big and when the real locus contains
a sphere or real projective plane (under the same stronger assumptions in this
last case). We finally present some explicit computations in the case of the
projective plane or quadric ellipsoid surface as well as the general formulas
used to get them, formulas which involve some relative invariants that we first
define.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:29:42 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Welschinger",
"Jean-Yves",
""
]
] |
0707.4318 | Boris Veytsman | Boris Veytsman and Leila Akhmadeyeva | Simple Mathematical Model Of Pathologic Microsatellite Expansions: When
Self-Reparation Does Not Work | null | J. Theor. Biol., 2006, v. 242, 401--408 | 10.1016/j.jtbi.2006.03.008 | null | q-bio.GN q-bio.CB | null | We propose a simple model of pathologic microsatellite expansion, and
describe an inherent self-repairing mechanism working against expansion. We
prove that if the probabilities of elementary expansions and contractions are
equal, microsatellite expansions are always self-repairing. If these
probabilities are different, self-reparation does not work. Mosaicism,
anticipation and reverse mutation cases are discussed in the framework of the
model. We explain these phenomena and provide some theoretical evidence for
their properties, for example the rarity of reverse mutations.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:31:57 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Veytsman",
"Boris",
""
],
[
"Akhmadeyeva",
"Leila",
""
]
] |
0707.4319 | Omar Gustavo Miranda | J. Barranco, O. G. Miranda, T. I. Rashba | Improved limit on electron neutrino charge radius through a new
evaluation of the weak mixing angle | 10 pages, 2 figures. Final published version | Phys.Lett.B662:431-435,2008 | 10.1016/j.physletb.2008.03.039 | MPP-2007-99 | hep-ph hep-ex | null | We have obtained a new limit on the electron neutrino effective charge radius
from a new evaluation of the weak mixing angle by a combined fit of all
electron-(anti)neutrino electron elastic scattering measurements. Weak mixing
angle is found to be sin^2 theta_W=0.259 \pm 0.025 in the low energy regime
below 100 MeV. The electron neutrino charge radius squared is bounded to be in
the range -0.13 10^-32 cm^2 < r^2 < 3.32 10^-32 cm^2 at 90 % C.L. Both results
improve previously published analyses. We also discuss perspectives of future
experiments to improve these constraints.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:40:38 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Mar 2008 22:31:27 GMT"
},
{
"version": "v3",
"created": "Tue, 22 Apr 2008 16:00:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Barranco",
"J.",
""
],
[
"Miranda",
"O. G.",
""
],
[
"Rashba",
"T. I.",
""
]
] |
0707.4320 | Rod Halburd | R. G. Halburd and N. J. Southall | Tropical Nevanlinna theory and ultra-discrete equations | 21 pages | null | null | null | nlin.SI nlin.CG | null | A tropical version of Nevanlinna theory is described in which the role of
meromorphic functions is played by continuous piecewise linear functions of a
real variable whose one-sided derivatives are integers at every point. These
functions are naturally defined on the max-plus (or tropical) semi-ring.
Analogues of the Nevanlinna characteristic, proximity and counting functions
are defined and versions of Nevanlinna's first main theorem, the lemma on the
logarithmic derivative and Clunie's lemma are proved.
As well as providing another example of a tropical or dequantized analogue of
an important area of complex analysis, this theory has applications to
so-called ultra-discrete equations. Preliminary results are presented
suggesting that the existence of finite-order max-plus meromorphic solutions
can be considered to be an ultra-discrete analogue of the Painlev'e property.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 21:46:11 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Halburd",
"R. G.",
""
],
[
"Southall",
"N. J.",
""
]
] |
0707.4321 | Razvan Radulescu M.D. | Razvan Tudor Radulescu | The insulin superfamily of growth-promoting proteins | 3 pages, 1 figure | null | null | null | q-bio.BM q-bio.SC | null | Recently, structural analysis of the human transferrin and growth hormone
(GH) amino acid sequences has unravelled that they harbor a motif identical to
a pattern found in viral oncoproteins known to bind the primarily nuclear tumor
suppressor retinoblastoma protein (RB). Since related signatures had previously
been identified also in insulin and the two insulin-like growth factors (IGFs),
the aim of the current study has been to investigate whether further hints
substantiating these reported homologies can be found in silico. Here,
additional similarities are presented supporting the notion of an insulin
superfamily of growth-promoting proteins with dual localization in the
extracellular environment and the intracellular space, particularly in the
nucleus, as well as characterized by a tropism for RB.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 22:54:16 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Radulescu",
"Razvan Tudor",
""
]
] |
0707.4322 | Nikolai V. Ivanov | Nikolai V. Ivanov, Lizhen Ji | Infinite topology of curve complexes and non-Poincare duality of
Teichmueller modular groups | 11 pages, no figures | null | null | null | math.GT math.GR | null | In this note, we fill in a gap in the literature by proving that the
Teichmueller modular groups (mapping class groups) are not Poincare duality
groups and the complexes of curves of surfaces have infinite homotopy type
(i.e. are not homotopy equivalent to a finite CW-complex).
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 23:56:14 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Ivanov",
"Nikolai V.",
""
],
[
"Ji",
"Lizhen",
""
]
] |
0707.4323 | Peter Phillips | Peter R. Phillips | Is the Mass Scale for Elementary Particles Classically Determined? | 17 pages, 9 figures, format for Phys. Rev. D | null | null | null | gr-qc | null | We investigate whether a mass scale for elementary particles can be derived
from interactions of particles with distant matter in the Universe, the
mechanism of the interaction being the classical vector potential, propagating
in a space of negative curvature. A possible context for such a mass scale is
conformal gravity. This theory may prove to be renormalizable, since all
coupling constants are dimensionless; conversely, however, there is no coupling
constant analogous to the conventional G to provide a starting point for a mass
scale calculation. We obtain the equations for propagation of the vector
potential of a charged particle moving in a plasma in a curved space. We then
show that distant matter will contribute to A**2, and that this non-thermal
part will eventually dominate the ordinary thermal part. At this point a
symmetry breaking transition of the Coleman-Weinberg type is possible, and
particle masses can be generated with m**2 of order A**2.
| [
{
"version": "v1",
"created": "Sun, 29 Jul 2007 23:27:24 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Phillips",
"Peter R.",
""
]
] |
0707.4324 | Anatoli Afanasjev | M. Matev, A.V. Afanasjev, J.Dobaczewski, G.A.Lalazissis, W.Nazarewicz | Additivity of effective quadrupole moments and angular momentum
alignments in the A~130 nuclei | 14 pages, 6 figures, submitted to Physics Review C | Phys.Rev.C76:034304,2007 | 10.1103/PhysRevC.76.034304 | null | nucl-th | null | The additivity principle of the extreme shell model stipulates that an
average value of a one-body operator be equal to the sum of the core
contribution and effective contributions of valence (particle or hole)
nucleons. For quadrupole moment and angular momentum operators, we test this
principle for highly and superdeformed rotational bands in the A~130 nuclei.
Calculations are done in the self-consistent cranked non-relativistic
Hartree-Fock and relativistic Hartree mean-field approaches. Results indicate
that the additivity principle is a valid concept that justifies the use of an
extreme single-particle model in an unpaired regime typical of high angular
momenta.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 00:12:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Matev",
"M.",
""
],
[
"Afanasjev",
"A. V.",
""
],
[
"Dobaczewski",
"J.",
""
],
[
"Lalazissis",
"G. A.",
""
],
[
"Nazarewicz",
"W.",
""
]
] |
0707.4325 | Bingwei Long | B. Long, U. van Kolck | Renormalization of Singular Potentials and Power Counting | 23 pages, 6 figures | AnnalsPhys.323:1304-1323,2008 | 10.1016/j.aop.2008.01.003 | UA-ET-07-03 | quant-ph nucl-th physics.atom-ph | null | We use a toy model to illustrate how to build effective theories for singular
potentials. We consider a central attractive 1/r^2 potential perturbed by a
1/r^4 correction. The power-counting rule, an important ingredient of effective
theory, is established by seeking the minimum set of short-range counterterms
that renormalize the scattering amplitude. We show that leading-order
counterterms are needed in all partial waves where the potential overcomes the
centrifugal barrier, and that the additional counterterms at next-to-leading
order are the ones expected on the basis of dimensional analysis.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 00:47:04 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 22:08:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Long",
"B.",
""
],
[
"van Kolck",
"U.",
""
]
] |
0707.4326 | Mark Dykman | M. I. Dykman | Exponential peak and scaling of work fluctuations in modulated systems | null | null | 10.1103/PhysRevE.77.021123 | null | cond-mat.stat-mech cond-mat.mes-hall | null | We extend the stationary-state work fluctuation theorem to periodically
modulated nonlinear systems. Such systems often have coexisting stable periodic
states. We show that work fluctuations sharply increase near a kinetic phase
transition where the state populations are close to each other. The work
variance is proportional here to the reciprocal rate of interstate switching.
We also show that the variance displays scaling with the distance to a
bifurcation point and find the critical exponent for a saddle-node bifurcation.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 00:57:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dykman",
"M. I.",
""
]
] |
0707.4327 | Tania Regimbau | T. Regimbau and B. Chauvineau | Stochastic background from extra-galactic double neutron stars | 13 pages, 7 figures - proceeding of a talk given at the 11th GWDAW,
to appear in CQG | Class.Quant.Grav.24:S627-S638,2007 | 10.1088/0264-9381/24/19/S25 | null | gr-qc astro-ph | null | We present Monte Carlo simulations of the extra galactic population of
inspiralling double neutron stars, and estimate its contribution to the
astrophysical gravitational wave background, in the frequency range of ground
based interferometers, corresponding to the last thousand seconds before the
last stable orbit when more than 96 percent of the signal is released. We show
that sources at redshift z>0.5 contribute to a truly continuous background
which may be detected by correlating third generation interferometers.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 01:09:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Regimbau",
"T.",
""
],
[
"Chauvineau",
"B.",
""
]
] |
0707.4328 | Victor J. W. Guo | Victor J. W. Guo and Jiang Zeng | Multiple extensions of a finite Euler's pentagonal number theorem and
the Lucas formulas | 11 pages, to appear in Discrete Mathematics. See also
http://math.univ-lyon1.fr/~guo | Discrete Math. 308 (2008), 4069--4078 | 10.1016/j.disc.2007.07.106 | null | math.CO | null | Motivated by the resemblance of a multivariate series identity and a finite
analogue of Euler's pentagonal number theorem, we study multiple extensions of
the latter formula. In a different direction we derive a common extension of
this multivariate series identity and two formulas of Lucas. Finally we give a
combinatorial proof of Lucas' formulas.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 02:12:25 GMT"
}
] | 2011-03-25T00:00:00 | [
[
"Guo",
"Victor J. W.",
""
],
[
"Zeng",
"Jiang",
""
]
] |
0707.4329 | Yoshifumi Ando | Yoshifumi Ando | Cobordisms of maps with singularities of a given class | null | null | null | null | math.GT | null | Let P be a connected smooth p-manifold. We describe the group of all
cobordism classes of smooth maps of n-manifolds to P with singularities of a
given $cal K$-invariant class in terms of certain stable homotopy groups by
applying the relative homotopy principle on the existence level. We also deal
with the oriented version and construct a classifying space to which this
oriented cobordism group is represented as the set of homotopy classes of P in
the codimension n<p and n\geqq p\geqq 2.
| [
{
"version": "v1",
"created": "Mon, 30 Jul 2007 03:39:00 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Apr 2008 07:51:58 GMT"
},
{
"version": "v3",
"created": "Wed, 14 May 2008 01:45:52 GMT"
}
] | 2008-05-14T00:00:00 | [
[
"Ando",
"Yoshifumi",
""
]
] |
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