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sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.1930 | Gang Bao | Gang Bao, Wei-Tou Ni, D. N. A. Shaul, H. M. Araujo, Lei Liu, T. J.
Sumner | Improved Simulation of the Mass Charging for ASTROD I | 20 pages, 14 figures, submitted to International Journal of Modern
Physics D | INTERNATIONAL JOURNAL OF MODERN PHYSICS D, Vol.17, No.7, 965 (July
2008) | 10.1142/S0218271808012632 | null | astro-ph | null | The electrostatic charging of the test mass in ASTROD I (Astrodynamical Space
Test of Relativity using Optical Devices I) mission can affect the quality of
the science data as a result of spurious Coulomb and Lorentz forces. To
estimate the size of the resultant disturbances, credible predictions of
charging rates and the charging noise are required. Using the GEANT4 software
toolkit, we present a detailed Monte Carlo simulation of the ASTROD I test mass
charging due to exposure of the spacecraft to galactic cosmic-ray (GCR) protons
and alpha particles (3He, 4He) in the space environment. A positive charging
rate of 33.3 e+/s at solar minimum is obtained. This figure reduces by 50% at
solar maximum. Based on this charging rate and factoring in the contribution of
minor cosmic-ray components, we calculate the acceleration noise and stiffness
associated with charging. We conclude that the acceleration noise arising from
Coulomb and Lorentz effects are well below the ASTROD I acceleration noise
limit at 0.1 mHz both at solar minimum and maximum. The coherent Fourier
components due to charging are investigated, it needs to be studied carefully
in order to ensure that these do not compromise the quality of science data in
the ASTROD I mission.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 06:59:51 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Bao",
"Gang",
""
],
[
"Ni",
"Wei-Tou",
""
],
[
"Shaul",
"D. N. A.",
""
],
[
"Araujo",
"H. M.",
""
],
[
"Liu",
"Lei",
""
],
[
"Sumner",
"T. J.",
""
]
] |
0707.1931 | Shun-Ichiro Koh | Shun-ichiro Koh | Shear viscosity and Bose statistics: Capillary flow above lambda point | 32pages, 7figures | null | null | null | cond-mat.supr-con cond-mat.stat-mech | null | The gradual fall of the shear viscosity below 2.8K, observed in a liquid
helium 4 flowing through a capillary, is examined. The disappearance of the
shear viscosity in a capillary flow is a manifestation of superfluidity in
dissipative phenomena, the onset mechanism of which is a subtle problem
compared to that of superfluidity in non-dissipative phenomena. Applying the
linear-response theory to the reciprocal of the shear viscosity coefficient, we
relate these two types of superfluidity using the Kramers-Kronig relation. We
obtain a formula describing the influence of Bose statistics on the kinematic
shear viscosity in terms of the susceptibility. Compared to an ordinary liquid,
a liquid helium 4 above the lambda point has a 1/1000 times smaller shear
viscosity coefficient. Hence, although in the normal phase, it is already an
anomalous liquid under the strong influence of Bose statistics. The coherent
many-body wave function grows to an intermediate size between a macroscopic and
a microscopic one, not as a thermal fluctuation but as a thermal equilibrium
state. Beginning with bosons without the condensate, we make a perturbation
calculation of its susceptibility with respect to the repulsive interaction. We
examine how, with decreasing temperature, the growth of the coherent wave
function gradually suppresses the shear viscosity, and finally leads to a
frictionless flow at the lambda-point.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 06:59:59 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Koh",
"Shun-ichiro",
""
]
] |
0707.1932 | Gilberto Medeiros Kremer | Guillermo Chac\'on--Acosta, Gilberto M. Kremer | Fokker-Planck type equations for a simple gas and for a
semi-relativistic Brownian motion from a relativistic kinetic theory | To appear in PRE | Physical Review E 76, 021201 (2007) | 10.1103/PhysRevE.76.021201 | null | cond-mat.stat-mech | null | A covariant Fokker-Planck type equation for a simple gas and an equation for
the Brownian motion are derived from a relativistic kinetic theory based on the
Boltzmann equation. For the simple gas the dynamic friction four-vector and the
diffusion tensor are identified and written in terms of integrals which take
into account the collision processes. In the case of Brownian motion, the
Brownian particles are considered as non-relativistic whereas the background
gas behaves as a relativistic gas. A general expression for the
semi-relativistic viscous friction coefficient is obtained and the particular
case of constant differential cross-section is analyzed for which the
non-relativistic and ultra relativistic limiting cases are calculated.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 07:24:48 GMT"
}
] | 2010-11-19T00:00:00 | [
[
"Chacón--Acosta",
"Guillermo",
""
],
[
"Kremer",
"Gilberto M.",
""
]
] |
0707.1933 | Yong-Wan Kim | Yun Soo Myung, Yong-Wan Kim, and Young-Jai Park | New attractor mechanism for spherically symmetric extremal black holes | 20 pages, 4 figures, Accepted for publication in Physical Review D.
This version includes revisions suggested by the referee | Phys.Rev.D76:104045,2007 | 10.1103/PhysRevD.76.104045 | null | hep-th gr-qc | null | We introduce a new attractor mechanism to find the entropy for spherically
symmetric extremal black holes. The key ingredient is to find a two-dimensional
(2D) dilaton gravity with the dilaton potential $V(\phi)$. The condition of an
attractor is given by $\nabla^2\phi=V(\phi_0)$ and
$\bar{R}_2=-V^{\prime}(\phi_0)$ and for a constant dilaton $ \phi=\phi_0$,
these are also used to find the location of the degenerate horizon $r=r_{e}$ of
an extremal black hole. As a nontrivial example, we consider an extremal
regular black hole obtained from the coupled system of Einstein gravity and
nonlinear electrodynamics. The desired Bekenstein-Hawking entropy is
successfully recovered from the generalized entropy formula combined with the
2D dilaton gravity, while the entropy function approach does not work for
obtaining this entropy.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 07:25:57 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 09:03:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Myung",
"Yun Soo",
""
],
[
"Kim",
"Yong-Wan",
""
],
[
"Park",
"Young-Jai",
""
]
] |
0707.1934 | Andreas Seeger | Gustavo Garrigos and Andreas Seeger | On plate decompositions of cone multipliers | This is the revised version to appear in the proceedings of the
Edinburgh Mathematical Society | Proceedings of the Edinburgh Mathematical Society, 52 (2009),
1-21. | null | null | math.CA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | An important inequality due to Wolff on plate decompositions of cone
multipliers is known to have consequences for a variety of problems in harmonic
analysis. We observe that the range in Wolff's inequality, for the conic and
the spherical versions, can be improved by using bilinear restriction results.
We also use this inequality to give some improved estimates on square functions
associated to decompositions of cone multipliers in low dimensions. This gives
a new L^4 bound for the cone multiplier operator in three dimensions.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 07:29:07 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jun 2008 22:12:58 GMT"
}
] | 2010-03-15T00:00:00 | [
[
"Garrigos",
"Gustavo",
""
],
[
"Seeger",
"Andreas",
""
]
] |
0707.1935 | Boris Hage | B. Hage, A. Franzen, J. DiGuglielmo, P. Marek, J. Fiur\'a\v{s}ek and
R. Schnabel | On the distillation and purification of phase-diffused squeezed states | null | New J. Phys. 9 (2007) 227 | 10.1088/1367-2630/9/7/227 | null | quant-ph | null | Recently it was discovered that non-Gaussian decoherence processes, such as
phase-diffusion, can be counteracted by purification and distillation protocols
that are solely built on Gaussian operations. Here, we make use of this
experimentally highly accessible regime, and provide a detailed experimental
and theoretical analysis of several strategies for purification/distillation
protocols on phase-diffused squeezed states. Our results provide valuable
information for the optimization of such protocols with respect to the choice
of the trigger quadrature, the trigger threshold value and the probability of
generating a distilled state.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 07:49:14 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 06:59:00 GMT"
}
] | 2007-07-17T00:00:00 | [
[
"Hage",
"B.",
""
],
[
"Franzen",
"A.",
""
],
[
"DiGuglielmo",
"J.",
""
],
[
"Marek",
"P.",
""
],
[
"Fiurášek",
"J.",
""
],
[
"Schnabel",
"R.",
""
]
] |
0707.1936 | Richard Hill | Richard Hill | A reinterpretation of Emerton's $p$-adic Banach spaces | 7 pages | null | null | null | math.NT | null | It is shown that the $p$-adic Banach spaces introduced by Emerton are
isomorphic to the cohomology groups of the sheaf of continuous $\Q_{p}$-valued
functions on a certain space. Some applications of this result are discussed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 17:12:11 GMT"
},
{
"version": "v2",
"created": "Sat, 14 Jul 2007 13:41:12 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Hill",
"Richard",
""
]
] |
0707.1937 | Catherine Cress | S. E. Bryan and C. M. Cress | Figure rotation of dark halos in CDM simulations | accepted to MNRAS, 8 pages | null | 10.1111/j.1365-2966.2007.12096.x | null | astro-ph | null | We investigate the figure rotation of dark matter halos identified in Lambda
CDM simulations. We find that when strict criteria are used to select suitable
halos for study, 5 of the 222 halos identified in our z=0 simulation output
undergo coherent figure rotation over a 5h^{-1}Gyr period. We discuss the
effects of varying the selection criteria and find that pattern speeds for a
much larger fraction of the halos can be measured when the criteria are
relaxed. Pattern speeds measured over a 1h^{-1}Gyr period follow a log-normal
distribution, centred at Omega_p = 0.25h rad/Gyr with a maximum value of 0.94h
rad/Gyr. Over a 5h^{-1}Gyr period, the average pattern speed of a halo is about
0.1h rad/Gyr and the largest pattern speed found is 0.24h rad/Gyr. Less than
half of the selected halos showed alignment between their figure rotation axis
and minor axis, the exact fraction being somewhat dependent on how one defines
a halo. While the pattern speeds observed are lower than those generally
thought capable of causing spiral structure, we note that coherent figure
rotation is found over very long periods and argue that further simulations
would be required before strong conclusions about spiral structure in all
galaxies could be drawn. We find no correlation between halo properties such as
total mass and the pattern speed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 08:40:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bryan",
"S. E.",
""
],
[
"Cress",
"C. M.",
""
]
] |
0707.1938 | Mikhail Kashchenko | M.P. Kashchenko, V.G.Chashchina | The Material Orientation Relationship for the BCC-HCP Transition | 7 pages, 3 figures | null | null | null | cond-mat.mtrl-sci | null | The dynamical model of forming of martensitic crystals for the bcc-hcp
transition is offered. It is shown that all macroscopic morphological
characters (the habit plane, the macroshear and the orientational relationship)
are expressed through elastic moduluses Cij of an initial bcc phase.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 08:29:47 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Kashchenko",
"M. P.",
""
],
[
"Chashchina",
"V. G.",
""
]
] |
0707.1939 | Bj\"orn Leder | Bjorn Leder | The Schroedinger functional for Gross-Neveu models | Ph.D. Thesis (Advisor: Dr. Rainer Sommer) | null | null | HU-EP-07/57 | hep-lat | null | Gross-Neveu type models with a finite number of fermion flavours are studied
on a two-dimensional Euclidean space-time lattice. The models are
asymptotically free and are invariant under a chiral symmetry. These
similarities to QCD make them perfect benchmark systems for fermion actions
used in large scale lattice QCD computations. The Schroedinger functional for
the Gross-Neveu models is defined for both, Wilson and Ginsparg-Wilson
fermions, and shown to be renormalisable in 1-loop lattice perturbation theory.
In two dimensions four fermion interactions of the Gross-Neveu models have
dimensionless coupling constants. The symmetry properties of the four fermion
interaction terms and the relations among them are discussed. For Wilson
fermions chiral symmetry is explicitly broken and additional terms must be
included in the action. Chiral symmetry is restored up to cut-off effects by
tuning the bare mass and one of the couplings. The critical mass and the
symmetry restoring coupling are computed to second order in lattice
perturbation theory. This result is used in the 1-loop computation of the
renormalised couplings and the associated beta-functions. The renormalised
couplings are defined in terms of suitable boundary-to-boundary correlation
functions. In the computation the known first order coefficients of the
beta-functions are reproduced. One of the couplings is found to have a
vanishing beta-function. The calculation is repeated for the recently proposed
Schroedinger functional with exact chiral symmetry, i.e. Ginsparg-Wilson
fermions. The renormalisation pattern is found to be the same as in the Wilson
case. Using the regularisation dependent finite part of the renormalised
couplings, the ratio of the Lambda-parameters is computed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 15:30:40 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Leder",
"Bjorn",
""
]
] |
0707.1940 | Fr\'ed\'eric Pont | F. Pont, R. L. Gilliland, C. Moutou, F. Bouchy, T. M. Brown, D.
Charbonneau, M. Mayor, D. Queloz, N. Santos, S. Udry | Hubble Space Telescope times-series photometry of the planetary transit
of HD189733: no moon, no rings, starspots | revised version. Significant updates and new figures; to appear in
Astronomy and Astrophysics | null | 10.1051/0004-6361:20078269 | null | astro-ph | null | We monitored three transits of the giant gas planet around the nearby K dwarf
HD 189733 with the ACS camera on the Hubble Space Telescope. The resulting
very-high accuracy lightcurve (signal-to-noise ratio near 15000 on individual
measurements, 35000 on 10-minute averages) allows a direct geometric
measurement of the orbital inclination, radius ratio and scale of the system: i
= 85.68 +- 0.04, Rpl/R*=0.1572 +- 0.0004, a/R*=8.92 +- 0.09. We derive improved
values for the stellar and planetary radius, R*=0.755+- 0.011 Rsol, Rpl=1.154
+- 0.017 RJ, and the transit ephemerides, Ttr=2453931.12048 +- 0.00002 + n
2.218581 +- 0.000002$. The HST data also reveal clear evidence of the planet
occulting spots on the surface of the star. At least one large spot complex
(>80000 km) is required to explain the observed flux residuals and their colour
evolution. This feature is compatible in amplitude and phase with the
variability observed simultaneously from the ground. No evidence for satellites
or rings around HD 189733b is seen in the HST lightcurve. This allows us to
exlude with a high probability the presence of Earth-sized moons and
Saturn-type debris rings around this planet. The timing of the three transits
sampled is stable to the level of a few seconds, excluding a massive second
planet in outer 2:1 resonance.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:00:29 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Sep 2007 11:47:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pont",
"F.",
""
],
[
"Gilliland",
"R. L.",
""
],
[
"Moutou",
"C.",
""
],
[
"Bouchy",
"F.",
""
],
[
"Brown",
"T. M.",
""
],
[
"Charbonneau",
"D.",
""
],
[
"Mayor",
"M.",
""
],
[
"Queloz",
"D.",
""
],
[
"Santos",
"N.",
""
],
[
"Udry",
"S.",
""
]
] |
0707.1941 | Shin'ichi Nojiri | Shin'ichi Nojiri and Sergei D. Odintsov | Unifying inflation with LambdaCDM epoch in modified f(R) gravity
consistent with Solar System tests | LaTeX 8 pages, version to appear in PLB, Appendix is added | Phys.Lett.B657:238-245,2007 | 10.1016/j.physletb.2007.10.027 | null | hep-th astro-ph gr-qc | null | We suggest two realistic f(R) and one F(G) modified gravities which are
consistent with local tests and cosmological bounds. The typical property of
such theories is the presence of the effective cosmological constant epochs in
such a way that early-time inflation and late-time cosmic acceleration are
naturally unified within single model. It is shown that classical instability
does not appear here and Newton law is respected. Some discussion of possible
anti-gravity regime appearence and related modification of the theory is done.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 08:45:51 GMT"
},
{
"version": "v2",
"created": "Sun, 14 Oct 2007 09:49:45 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"Nojiri",
"Shin'ichi",
""
],
[
"Odintsov",
"Sergei D.",
""
]
] |
0707.1942 | Martin Hardcastle | J. L. Goodger, M. J. Hardcastle and J. H. Croston | Inverse-Compton emission from the lobes of 3C353 | 5 pages; to appear in "Extragalactic Jets: Theory and Observation
from Radio to Gamma Ray", eds. T. A. Rector and D. S. De Young, ASP
conference series | null | 10.1111/j.1365-2966.2008.13028.x | null | astro-ph | null | Analysis of the radio synchrotron and X-ray inverse-Compton emission from
radio-loud active galaxies allows us to determine their particle acceleration
processes and electron energy spectra. Previous studies have provided new
constraints on the total energy budget and particle content of powerful radio
galaxies and quasars; however, in most cases the sources are too faint in the
X-ray to obtain spatial information. We present archival and new
multi-frequency radio observations from the VLA and GMRT, and XMM-Newton
observations of the bright FRII radio galaxy 3C353 which lies on the edge of
the X-ray-luminous cluster Zw 1718.1-0108. The X-ray observations detect both
the inverse-Compton emission from the radio galaxy lobes and thermal emission
from the hot phase of the intracluster medium. We discuss the properties of the
particle energy spectrum as a function of position in the lobe, as well as the
properties of the merging cluster.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 08:55:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Goodger",
"J. L.",
""
],
[
"Hardcastle",
"M. J.",
""
],
[
"Croston",
"J. H.",
""
]
] |
0707.1943 | Christian Corda cordac | Christian Corda | Analysis of the transverse effect of Einstein's gravitational waves | Review paper, accepted for the International Journal of Modern
Physics A | Int.J.Mod.Phys.A22:4859-4881,2007 | 10.1142/S0217751X07037172 | null | gr-qc | null | The investigation of the transverse effect of gravitational waves (GWs) could
constitute a further tool to discriminate among several relativistic theories
of gravity on the ground. After a review of the TT gauge, the transverse effect
of GWs arising by standard general relativity (called Einstein's GWs in this
paper) is reanalized with a different choice of coordinates. In the chosen
gauge test masses have an apparent motion in the direction of propagation of
the wave, while in the transverse direction they appear at rest. Of course,
this is only a gauge artefact. In fact, from careful investigation of this
particular gauge, it is shown that the tidal forces associated with GWs act
along the directions orthogonal to the direction of propagation of waves. In
the analysis it is also shown, in a heuristic way, that the transverse effect
of Einstein's GWs arises from the propagation of the waves at the speed of the
light, thus only massless GWs are purely transverse. But, because the physics
of gravitational waves has to be investigated by studing the tidal forces as
appearing in the geodesic deviation equation and directly in a laboratory
environment on Earth, an analysis of these tidal forces and of the transverse
effect in the frame of the local observer is also performed. After this, for a
further better understanding of the transverse effect, an example of a wave,
which arises from scalar tensor gravity, with both transverse and genuinely
longitudinal modes is given and discussed. In the example the connection
between the longitudinal component and the velocity of the wave will be
mathematical shown.
At the end of this paper the review of the TT gauge is completed, recovering
the gauge invariance between the presented gauge and the TT one.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:11:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Corda",
"Christian",
""
]
] |
0707.1944 | Holger Baumgardt | Holger Baumgardt, Pavel Kroupa | A comprehensive set of simulations studying the influence of gas
expulsion on star cluster evolution | 12 pages, 9 figures, MNRAS accepted | null | 10.1111/j.1365-2966.2007.12209.x | null | astro-ph | null | We have carried out a large set of N-body simulations studying the effect of
residual-gas expulsion on the survival rate and final properties of star
clusters.
We have varied the star formation efficiency, gas expulsion timescale and
strength of the external tidal field, obtaining a three-dimensional grid of
models which can be used to predict the evolution of individual star clusters
or whole star cluster systems by interpolating between our runs. The complete
data of these simulations is made available on the Internet.
Our simulations show that cluster sizes, bound mass fraction and velocity
profile are strongly influenced by the details of the gas expulsion. Although
star clusters can survive star formation efficiencies as low as 10% if the
tidal field is weak and the gas is removed only slowly, our simulations
indicate that most star clusters are destroyed or suffer dramatic loss of stars
during the gas removal phase. Surviving clusters have typically expanded by a
factor 3 or 4 due to gas removal, implying that star clusters formed more
concentrated than as we see them today. Maximum expansion factors seen in our
runs are around 10. If gas is removed on timescales smaller than the initial
crossing time, star clusters acquire strongly radially anisotropic velocity
dispersions outside their half-mass radii. Observed velocity profiles of star
clusters can therefore be used as a constraint on the physics of cluster
formation.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:19:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Baumgardt",
"Holger",
""
],
[
"Kroupa",
"Pavel",
""
]
] |
0707.1945 | Ozay Gurtug | Ozay Gurtug and Mustafa Halilsoy | Effect of NUT parameter on the analytic extension of the Cauchy horizon
that develop in colliding wave spacetimes | 26 pages. 3 ps figures | IJMPA, 24 (2009) 3171. | 10.1142/S0217751X09044243 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Cauchy horizon forming colliding wave solution due to Chandrasekhar and
Xanthopoulos (CX) has been generalized by inclusion of the NUT (Newman - Unti -
Tamburino) parameter. This is done by transforming the part of the inner
horizon region of a Kerr-Newman-NUT black hole into the space of colliding
waves. By taking appropriate combination of Killing vectors and analytically
extending beyond the Cauchy horizon the time-like hyperbolic sigularities are
resolved as well. This provides another example of its kind among the type - D
metrics with special emphasis on the role of the NUT parameter. Finally, it is
shown that horizons of colliding higher dimensional plane waves obtained from
the black p-branes undergoes a similar procedure of analytic extension.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:16:11 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Dec 2008 02:59:41 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Gurtug",
"Ozay",
""
],
[
"Halilsoy",
"Mustafa",
""
]
] |
0707.1946 | Isabel Fernandez | Isabel Fernandez and Francisco J. Lopez | The uniqueness of the helicoid in the Lorentz-Minkowski space L3 | Corrected gap in the proof of former Corollary 5.1 | null | null | null | math.DG | null | In this paper we deal with the uniqueness of the Lorentzian helicoid and
Enneper's surface among properly embedded maximal surfaces with lightlike
boundary of mirror symmetry in the Lorentz-Minkowski space L3.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:47:58 GMT"
},
{
"version": "v2",
"created": "Tue, 25 Sep 2007 18:27:39 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Dec 2007 12:42:29 GMT"
}
] | 2007-12-04T00:00:00 | [
[
"Fernandez",
"Isabel",
""
],
[
"Lopez",
"Francisco J.",
""
]
] |
0707.1947 | Yu Xin | Yu Xin, Runyao Duan | Conditions for entanglement transformation between a class of
multipartite pure states with generalized Schmidt decompositions | 3 pages (Revetex 4), no figures. A brief note on entanglement
transformation. Comments are welcome | Phys.Rev.A 76, 044301 (2007) | 10.1103/PhysRevA.76.044301 | null | quant-ph | null | In this note we generalize Nielsen's marjoization criterion for the
convertibility of bipartite pure states [Phys. Rev. Lett \textbf{83},
436(1999)] to a special class of multipartite pure states which have
generalized Schmidt decompositions.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:18:17 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 14:37:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Xin",
"Yu",
""
],
[
"Duan",
"Runyao",
""
]
] |
0707.1948 | Tomohiro Matsuda | Tomohiro Matsuda | NO Curvatons or Hybrid Quintessential Inflation | 12 pages, no figure, added references | JCAP0708:003,2007 | 10.1088/1475-7516/2007/08/003 | null | hep-ph astro-ph hep-th | null | We consider a curvaton scenario in which the late-time domination and the
generation of the curvature perturbation is achieved by a non-oscillatory (NO)
curvaton potential. Instead of considering the conventional curvaton
oscillation, we consider ``weak trapping'' after preheating, which modifies the
evolution of the curvaton density after preheating. The primordial isocurvature
perturbation related to the curvaton is once converted into the fluctuation of
the number density of the preheat field through inhomogeneous preheating. Then
the evolution of the curvatons and the preheat field is controlled by the
preheat-field number density. The density of these fields decreases slightly
slower than the standard matter density which suggests that these fields will
grow with time. Finally, the preheat field decays to reheat the Universe
leaving behind the curvature perturbation. In our scenario the task of the
standard curvaton is not executed solely by the curvaton itself but is
partially shared with the preheat field. NO curvatons can be considered as the
hybrid version of the quintessential inflationary model.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:22:20 GMT"
},
{
"version": "v2",
"created": "Sun, 15 Jul 2007 06:06:30 GMT"
},
{
"version": "v3",
"created": "Fri, 27 Jul 2007 14:43:45 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Matsuda",
"Tomohiro",
""
]
] |
0707.1949 | D. P. Roy | D. P. Roy | SUSY Search in Future Collider and Dark Matter Experiments | 12 pages pdf file, To appear in Proc 2nd Intl Workshop on Theoretical
High Energy Physics, Roorkee, India, AIP Press (2007) | AIPConf.Proc.939:63-74,2007 | 10.1063/1.2803788 | null | hep-ph | null | The lightest superparticle in the MSSM is expected to be a Bino, Higgsino or
Wino. We consider the dark matter abundance constraint on these LSP scenarios
in the minimal SUGRA and AMSB models. We discuss the resulting collider signals
for the Bino LSP at LHC and the Higgsino and Wino LSP at CLIC. The Bino,
Higgsino and Wino LSP signals in dark matter experiments are also discussed
briefly. We conclude with a discussion of these LSP scenarios in nonminimal
SUSY models.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:34:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Roy",
"D. P.",
""
]
] |
0707.1950 | Evgeny Sklyanin | Vadim Kuznetsov and Evgeny Sklyanin | B\"acklund Transformation for the BC-Type Toda Lattice | This is a contribution to the Vadim Kuznetsov Memorial Issue on
Integrable Systems and Related Topics, published in SIGMA (Symmetry,
Integrability and Geometry: Methods and Applications) at
http://www.emis.de/journals/SIGMA/ | SIGMA 3 (2007), 080, 17 pages | 10.3842/SIGMA.2007.080 | null | nlin.SI math-ph math.MP | null | We study an integrable case of n-particle Toda lattice: open chain with
boundary terms containing 4 parameters. For this model we construct a
B\"acklund transformation and prove its basic properties: canonicity,
commutativity and spectrality. The B\"acklund transformation can be also viewed
as a discretized time dynamics. Two Lax matrices are used: of order 2 and of
order 2n+2, which are mutually dual, sharing the same spectral curve.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:38:55 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 04:46:26 GMT"
}
] | 2008-04-24T00:00:00 | [
[
"Kuznetsov",
"Vadim",
""
],
[
"Sklyanin",
"Evgeny",
""
]
] |
0707.1951 | M. Angeles Perez Garcia | M. Angeles Perez-Garcia, K. Tsushima, A. Valcarce | Binding energies and modelling of nuclei in semiclassical simulations | 10 pages, 5 figures. Manuscript final version. Accepted for
publication in Physics Letters B | Phys.Lett.B660:600-603,2008 | 10.1016/j.physletb.2008.01.041 | null | nucl-th astro-ph | null | We study the binding energies of spin-isospin saturated nuclei with nucleon
number $8 \le A \le 100$ in semiclassical Monte Carlo many-body simulations.
The model Hamiltonian consists of, (i) nucleon kinetic energy, (ii) a
nucleon-nucleon interaction potential, and (iii) an effective Pauli potential
which depends on density. The basic ingredients of the nucleon-nucleon
potential are, a short-range repulsion, and a medium-range attraction. Our
results demonstrate that one can always expect to obtain the empirical binding
energies for a set of nuclei by introducing a proper density dependent Pauli
potential. The present work suggests a simple, pragmatic procedure for
modelling a set of nuclei calibrated by the empirical binding energies for a
given NN interaction potential. Then, each set of modelled nuclei can be tested
by studying other properties of nuclei in semiclassical simulations.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:45:11 GMT"
},
{
"version": "v2",
"created": "Sun, 27 Jan 2008 18:56:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Perez-Garcia",
"M. Angeles",
""
],
[
"Tsushima",
"K.",
""
],
[
"Valcarce",
"A.",
""
]
] |
0707.1952 | Jifeng Chu, Donal O'Regan and Meirong Zhang | Jifeng Chu, Donal O'Regan and Meirong Zhang | Existence of positive solutions for nonlinear systems | 10 pages | null | null | null | math.AP | null | This paper deals with the existence of positive solutions for the nonlinear
system q(t)\phi(p(t)u'_{i}(t)))'+f^{i}(t,\textbf{u})=0,\quad 0<t<1,\quad
i=1,2,...,n. This system often arises in the study of positive radial solutions
of nonlinear elliptic system. Here $\textbf{u}=(u_{1},...,u_{n})$ and $f^{i},
i=1,2,...,n$ are continuous and nonnegative functions, $p(t), q(t)\hbox{\rm :}
[0,1]\to (0,\oo)$ are continuous functions. Moreover, we characterize the
eigenvalue intervals for (q(t)\phi(p(t)u'_{i}(t)))'+\lambda h_{i}(t)g^{i}
(\textbf{u})=0, \quad 0<t<1,\quad i=1,2,...,n. The proof is based on a
well-known fixed point theorem in cones.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:47:03 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Chu",
"Jifeng",
""
],
[
"O'Regan",
"Donal",
""
],
[
"Zhang",
"Meirong",
""
]
] |
0707.1953 | Maria Gloria Pini | Maria Gloria Pini and Angelo Rettori | Effect of antiferromagnetic exchange interactions on the Glauber
dynamics of one-dimensional Ising models | 5 figures. Phys. Rev. B (accepted July 12, 2007) | null | 10.1103/PhysRevB.76.064407 | null | cond-mat.mtrl-sci cond-mat.stat-mech | null | We study the effect of antiferromagnetic interactions on the single spin-flip
Glauber dynamics of two different one-dimensional (1D) Ising models with spin
$\pm 1$. The first model is an Ising chain with antiferromagnetic exchange
interaction limited to nearest neighbors and subject to an oscillating magnetic
field. The system of master equations describing the time evolution of
sublattice magnetizations can easily be solved within a linear field
approximation and a long time limit. Resonant behavior of the magnetization as
a function of temperature (stochastic resonance) is found, at low frequency,
only when spins on opposite sublattices are uncompensated owing to different
gyromagnetic factors (i.e., in the presence of a ferrimagnetic short range
order). The second model is the axial next-nearest neighbor Ising (ANNNI)
chain, where an antiferromagnetic exchange between next-nearest neighbors (nnn)
is assumed to compete with a nearest-neighbor (nn) exchange interaction of
either sign. The long time response of the model to a weak, oscillating
magnetic field is investigated in the framework of a decoupling approximation
for three-spin correlation functions, which is required to close the system of
master equations. The calculation, within such an approximate theoretical
scheme, of the dynamic critical exponent z, defined as ${1/\tau} \approx ({1/
{\xi}})^z$ (where \tau is the longest relaxation time and \xi is the
correlation length of the chain), suggests that the T=0 single spin-flip
Glauber dynamics of the ANNNI chain is in a different universality class than
that of the unfrustrated Ising chain.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:48:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pini",
"Maria Gloria",
""
],
[
"Rettori",
"Angelo",
""
]
] |
0707.1954 | Alessandro Nordio | A. Nordio, C.-F. Chiasserini, E. Viterbo | Bandlimited Field Reconstruction for Wireless Sensor Networks | null | null | null | null | cs.OH | null | Wireless sensor networks are often used for environmental monitoring
applications. In this context sampling and reconstruction of a physical field
is one of the most important problems to solve. We focus on a bandlimited field
and find under which conditions on the network topology the reconstruction of
the field is successful, with a given probability. We review irregular sampling
theory, and analyze the problem using random matrix theory. We show that even a
very irregular spatial distribution of sensors may lead to a successful signal
reconstruction, provided that the number of collected samples is large enough
with respect to the field bandwidth. Furthermore, we give the basis to
analytically determine the probability of successful field reconstruction.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:54:54 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Nordio",
"A.",
""
],
[
"Chiasserini",
"C. -F.",
""
],
[
"Viterbo",
"E.",
""
]
] |
0707.1955 | Yongfu Su and Xiaolong Qin | Yongfu Su and Xiaolong Qin | Strong convergence of modified Ishikawa iterations for nonlinear
mappings | 11 pages | null | null | null | math.FA | null | In this paper, we prove a strong convergence theorem of modified Ishikawa
iterations for relatively asymptotically nonexpansive mappings in Banach space.
Our results extend and improve the recent results by Nakajo, Takahashi, Kim,
Xu, Matsushita and some others.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:56:07 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Su",
"Yongfu",
""
],
[
"Qin",
"Xiaolong",
""
]
] |
0707.1956 | Thomas Wellens | Thomas Wellens, Benoit Gremaud | Nonlinear coherent transport of waves in disordered media | 4 pages, 3 figures | null | 10.1103/PhysRevLett.100.033902 | null | cond-mat.mes-hall cond-mat.dis-nn | null | We present a diagrammatic theory for coherent backscattering from disordered
dilute media in the nonlinear regime. The approach is non-perturbative in the
strength of the nonlinearity. We show that the coherent backscattering
enhancement factor is strongly affected by the nonlinearity, and corroborate
these results by numerical simulations. Our theory can be applied to several
physical scenarios like scattering of light in nonlinear Kerr media, or
propagation of matter waves in disordered potentials.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 16:54:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wellens",
"Thomas",
""
],
[
"Gremaud",
"Benoit",
""
]
] |
0707.1957 | Damien Chablat | Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN) | Moveability and Collision Analysis for Fully-Parallel Manipulators | null | 12th CISM-IFTOMM Symposium (07/1998) 1-8 | null | null | cs.RO | null | The aim of this paper is to characterize the moveability of fully-parallel
manipulators in the presence of obstacles. Fully parallel manipulators are used
in applications where accuracy, stiffness or high speeds and accelerations are
required \cite{Merlet:97}. However, one of its main drawbacks is a relatively
small workspace compared to the one of serial manipulators. This is due mainly
to the existence of potential internal collisions, and the existence of
singularities. In this paper, the notion of free aspect is defined which
permits to exhibit domains of the workspace and the joint space free of
singularity and collision. The main application of this study is the
moveability analysis in the workspace of the manipulator as well as
path-planning, control and design.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 09:59:25 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
]
] |
0707.1958 | Acetinkaya and Nozalp | A. Cetinkaya and N. Ozalp | Solutions for a class of iterated singular equations | 7 pages | null | null | null | math.AP | null | Some fundamental solutions of radial type for a class of iterated elliptic
singular equations including the iterated Euler equation are given.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:10:14 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Cetinkaya",
"A.",
""
],
[
"Ozalp",
"N.",
""
]
] |
0707.1959 | Christophe Chatelain | Jean-Charles Walter (LPM), Christophe Chatelain (LPM) | Logarithmic corrections in the aging of the fully-frustrated Ising model | 12 pages, 9 figures | J. Stat. Mech. (2008) P07005 | 10.1088/1742-5468/2008/07/P07005 | null | cond-mat.stat-mech | null | We study the dynamics of the critical two-dimensional fully-frustrated Ising
model by means of Monte Carlo simulations. The dynamical exponent is estimated
at equilibrium and is shown to be compatible with the value $z_c=2$. In a
second step, the system is prepared in the paramagnetic phase and then quenched
at its critical temperature $T_c=0$. Numerical evidences for the existence of
logarithmic corrections in the aging regime are presented. These corrections
may be related to the topological defects observed in other fully-frustrated
models. The autocorrelation exponent is estimated to be $\lambda=d$ as for the
Ising chain quenched at $T_c=0$.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:17:22 GMT"
},
{
"version": "v2",
"created": "Wed, 28 May 2008 14:58:18 GMT"
}
] | 2008-07-12T00:00:00 | [
[
"Walter",
"Jean-Charles",
"",
"LPM"
],
[
"Chatelain",
"Christophe",
"",
"LPM"
]
] |
0707.1960 | Dimitar Stoyanov | Dimitar G. Stoyanov | A planar vacuum diode with electrons possessing velocity distribution
function | 10 pages, 2 figures; corrected typos. Submitted for consideration to
the Journal of Applied Electromagnetism | Journal of Applied Electromagnetism (ISSN 1109-1606), Vol. 9, No
2, December 2007, pp 54-64, Athens-GREECE | null | null | physics.gen-ph physics.class-ph | null | The current-voltage characteristic of a planar vacuum diode with electrons
possessing velocity distribution function during an emission from the cathode
(electron beam) is theoretically considered in this article. The electron beam
movement in the volume is examined. An integral-differential equation for the
electric field potential is got in a correct form. A current-voltage
characteristic of the diode for a model function of the velocity distribution
of the emitted electrons is obtained.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:20:49 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jul 2007 14:51:11 GMT"
}
] | 2008-05-14T00:00:00 | [
[
"Stoyanov",
"Dimitar G.",
""
]
] |
0707.1961 | Ali Ghaffari | Ali Ghaffari | Ergodic theory of amenable semigroup actions | 9 pages | null | null | null | math.DS math.FA | null | In this paper, among other things, we state and prove the mean ergodic
theorem for amenable semigroup algebras.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:21:40 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Ghaffari",
"Ali",
""
]
] |
0707.1962 | K Gowri Navada | K Gowri Navada | Some further remarks on good sets | 7 pages | null | null | null | math.FA | null | We show that in n-fold cartesian product, n >= 4, a related component need
not be a full component. We also prove that when n >= 4, uniform boundedness of
lengths of geodesics is not a necessary condition for boundedness of solutions
of (1) for bounded function f.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:25:18 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Navada",
"K Gowri",
""
]
] |
0707.1963 | Piotr Fronczak | Piotr Fronczak, Agata Fronczak and Janusz A. Holyst | Kauffman Boolean model in undirected scale free networks | null | null | 10.1103/PhysRevE.77.036119 | null | cond-mat.dis-nn cond-mat.stat-mech | null | We investigate analytically and numerically the critical line in undirected
random Boolean networks with arbitrary degree distributions, including
scale-free topology of connections $P(k)\sim k^{-\gamma}$. We show that in
infinite scale-free networks the transition between frozen and chaotic phase
occurs for $3<\gamma < 3.5$. The observation is interesting for two reasons.
First, since most of critical phenomena in scale-free networks reveal their
non-trivial character for $\gamma<3$, the position of the critical line in
Kauffman model seems to be an important exception from the rule. Second, since
gene regulatory networks are characterized by scale-free topology with
$\gamma<3$, the observation that in finite-size networks the mentioned
transition moves towards smaller $\gamma$ is an argument for Kauffman model as
a good starting point to model real systems. We also explain that the
unattainability of the critical line in numerical simulations of classical
random graphs is due to percolation phenomena.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:27:19 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 09:43:13 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Fronczak",
"Piotr",
""
],
[
"Fronczak",
"Agata",
""
],
[
"Holyst",
"Janusz A.",
""
]
] |
0707.1964 | Sanjay Kumar and Kanwar Jatinder Singh | Sanjay Kumar and Kanwar Jatinder Singh | Weighted composition operators on weighted Bergman spaces of bounded
symmetric domains | 11 pages | null | null | null | math.FA math.OA | null | In this paper, we study the weighted compositon operators on weighted Bergman
spaces of bounded symmetric domains. The necessary and sufficient conditions
for a weighted composition operator $W_{\phi,\psi}$ to be bounded and compact
are studied by using the Carleson measure techniques. In the last section, we
study the Schatten p-class weighted composition operators.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:32:28 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Kumar",
"Sanjay",
""
],
[
"Singh",
"Kanwar Jatinder",
""
]
] |
0707.1965 | Olivier C. Martin | Z. Burda, A. Krzywicki and O.C. Martin | Network of inherent structures in spin glasses: scaling and scale-free
distributions | minor changes and references added | Phys. Rev. E 76, 051107 (2007). | 10.1103/PhysRevE.76.051107 | null | cond-mat.dis-nn cond-mat.stat-mech | null | The local minima (inherent structures) of a system and their associated
transition links give rise to a network. Here we consider the topological and
distance properties of such a network in the context of spin glasses. We use
steepest descent dynamics, determining for each disorder sample the transition
links appearing within a given barrier height. We find that differences between
linked inherent structures are typically associated with local clusters of
spins; we interpret this within a framework based on droplets in which the
characteristic ``length scale'' grows with the barrier height. We also consider
the network connectivity and the degrees of its nodes. Interestingly, for spin
glasses based on random graphs, the degree distribution of the network of
inherent structures exhibits a non-trivial scale-free tail.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:35:29 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 07:34:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Burda",
"Z.",
""
],
[
"Krzywicki",
"A.",
""
],
[
"Martin",
"O. C.",
""
]
] |
0707.1966 | A J Shaiju and Sheetal Dharmatti | A J Shaiju and Sheetal Dharmatti | Infinite dimensional differential games with hybrid controls | null | null | null | null | math.OC | null | A two-person zero-sum infinite dimensional differential game of infinite
duration with discounted payoff involving hybrid controls is studied. The
minimizing player is allowed to take continuous, switching and impulse controls
whereas the maximizing player is allowed to take continuous and switching
controls. By taking strategies in the sense of Elliott--Kalton, we prove the
existence of value and characterize it as the unique viscosity solution of the
associated system of quasi-variational inequalities.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:35:50 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Shaiju",
"A J",
""
],
[
"Dharmatti",
"Sheetal",
""
]
] |
0707.1967 | Rana Barua and Ashok Maitra | Rana Barua and Ashok Maitra | Borel hierarchies in infinite products of Polish spaces | 7 pages | null | null | null | math.LO | null | Let H be a product of countably infinite number of copies of an uncountable
Polish space X. Let $\Sigma_\xi$ $(\bar {\Sigma}_\xi)$ be the class of Borel
sets of additive class \xi for the product of copies of the discrete topology
on X (the Polish topology on X), and let ${\cal B} = \cup_{\xi < \omega_1}
\bar{\Sigma}_\xi$. We prove in the L\'{e}vy--Solovay model that
\bar{\Sigma}_\xi =\Sigma_{\xi}\cap {\cal B} for $1 \leq \xi < \omega_1$.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:40:42 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Barua",
"Rana",
""
],
[
"Maitra",
"Ashok",
""
]
] |
0707.1968 | Guang-hui Cai and Hang Wu | Guang-hui Cai and Hang Wu | Law of iterated logarithm for NA sequences with non-identical
distributions | null | null | null | null | math.PR | null | Based on a law of the iterated logarithm for independent random variables
sequences, an iterated logarithm theorem for NA sequences with non-identical
distributions is obtained. The proof is based on a Kolmogrov-type exponential
inequality.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:44:02 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Cai",
"Guang-hui",
""
],
[
"Wu",
"Hang",
""
]
] |
0707.1969 | Richard Hendricks | R. J. Hendricks, J. L. S{\o}rensen, C. Champenois, M. Knoop and M.
Drewsen | Doppler cooling of calcium ions using a dipole-forbidden transition | 4 pages, 4 figures, minor changes to commentary and references | null | 10.1103/PhysRevA.77.021401 | null | quant-ph | null | Doppler cooling of calcium ions has been experimentally demonstrated using
the S1/2 to D5/2 dipole-forbidden transition. Scattering forces and
fluorescence levels a factor of 5 smaller than for usual Doppler cooling on the
dipole allowed S1/2 to P1/2 transition have been achieved. Since the light
scattered from the ions can be monitored at (violet) wavelengths that are very
different from the excitation wavelengths, single ions can be detected with an
essentially zero background level. This, as well as other features of the
cooling scheme, can be extremely valuable for ion trap based quantum
information processing.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 10:52:42 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jan 2008 10:04:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hendricks",
"R. J.",
""
],
[
"Sørensen",
"J. L.",
""
],
[
"Champenois",
"C.",
""
],
[
"Knoop",
"M.",
""
],
[
"Drewsen",
"M.",
""
]
] |
0707.1970 | Kejie Fang | Kejie Fang, Bin Chen, Wei Xue | Non-commutative Geometry Modified Non-Gaussianities of Cosmological
Perturbation | 26 pages, 3 figures Added references, changed content | Phys.Rev.D77:063523,2008 | 10.1103/PhysRevD.77.063523 | null | astro-ph hep-th | null | We investigate the noncommutative effect on the non-Gaussianities of
primordial cosmological perturbation. In the lowest order of string length and
slow-roll parameter, we find that in the models with small speed of sound the
noncommutative modifications could be observable if assuming a relatively low
string scale. In particular, the dominant modification of non-Gaussianity
estimator f_{NL} could reach O(1) in DBI inflation and K-inflation. The
corrections are sensitive to the speed of sound and the choice of string length
scale. Moreover the shapes of the corrected non-Gaussianities are distinct from
that of ordinary ones.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 16:26:11 GMT"
},
{
"version": "v2",
"created": "Sun, 13 Jan 2008 04:26:19 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Fang",
"Kejie",
""
],
[
"Chen",
"Bin",
""
],
[
"Xue",
"Wei",
""
]
] |
0707.1971 | Mikio Kozuma | M. Arikawa, K. Honda, D. Akamatsu, Y. Yokoi, K. Akiba, S. Nagatsuka,
A. Furusawa, and M. Kozuma | Observation of Electromagnetically Induced Transparency for a Squeezed
Vacuum with the Time Domain Method | null | Optics Express, Vol. 15, Issue 19, pp. 11849-11854 (2007) | 10.1364/OE.15.011849 | null | quant-ph | null | A probe light in a squeezed vacuum state was injected into cold 87 $Rb atoms
with an intense control light in a coherent state. A sub-MHz window was created
due to electromagnetically induced transparency, and the incident squeezed
vacuum could pass through the cold atoms without optical loss, as was
successfully monitored using a time-domain homodyne method.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:00:51 GMT"
},
{
"version": "v2",
"created": "Sun, 27 Jan 2008 12:59:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Arikawa",
"M.",
""
],
[
"Honda",
"K.",
""
],
[
"Akamatsu",
"D.",
""
],
[
"Yokoi",
"Y.",
""
],
[
"Akiba",
"K.",
""
],
[
"Nagatsuka",
"S.",
""
],
[
"Furusawa",
"A.",
""
],
[
"Kozuma",
"M.",
""
]
] |
0707.1972 | Stefan Haesen | Stefan Haesen and Miguel Ortega | Boost invariant marginally trapped surfaces in Minkowski 4-space | 13 pages, comment added in section 2 | Class.Quant.Grav.24:5441-5452,2007 | 10.1088/0264-9381/24/22/009 | null | gr-qc | null | The extremal and partly marginally trapped surfaces in Minkowski 4-space,
which are invariant under the group of boost isometries, are classified.
Moreover, it is shown that there do not exist extremal surfaces of this kind
with constant Gaussian curvature. A procedure is given in order to construct a
partly marginally trapped surface by gluing two marginally trapped surfaces
which are invariant under the group of boost isometries. As an application, a
proper star-surface is constructed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:07:08 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Oct 2007 07:30:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Haesen",
"Stefan",
""
],
[
"Ortega",
"Miguel",
""
]
] |
0707.1973 | Jeppe Johansen | J. Johansen, S. Stobbe, I.S. Nikolaev, T. Lund-Hansen, P.T.
Kristensen, J.M. Hvam, W.L. Vos, and P. Lodahl | Size-Dependence of the Wavefunction of Self-Assembled Quantum Dots | 5 pages, 3 figures | Phys. Rev. B, vol 77, page 073303, 2008 | 10.1103/PhysRevB.77.073303 | null | cond-mat.other | null | The radiative and non-radiative decay rates of InAs quantum dots are measured
by controlling the local density of optical states near an interface. From
time-resolved measurements we extract the oscillator strength and the quantum
efficiency and their dependence on emission energy. From our results and a
theoretical model we determine the striking dependence of the overlap of the
electron and hole wavefunctions on the quantum dot size. We conclude that the
optical quality is best for large quantum dots, which is important in order to
optimally tailor quantum dot emitters for, e.g., quantum electrodynamics
experiments.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:15:05 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 07:01:23 GMT"
},
{
"version": "v3",
"created": "Mon, 10 Dec 2007 13:57:33 GMT"
}
] | 2008-02-18T00:00:00 | [
[
"Johansen",
"J.",
""
],
[
"Stobbe",
"S.",
""
],
[
"Nikolaev",
"I. S.",
""
],
[
"Lund-Hansen",
"T.",
""
],
[
"Kristensen",
"P. T.",
""
],
[
"Hvam",
"J. M.",
""
],
[
"Vos",
"W. L.",
""
],
[
"Lodahl",
"P.",
""
]
] |
0707.1974 | Mridula Garg and Alka Rao | Mridula Garg and Alka Rao | Fractional extensions of some boundary value problems in oil strata | 14 pages | null | null | null | math.AP | null | In the present paper, we solve three boundary value problems related to the
temperature field in oil strata -- the fractional extensions of the incomplete
lumped formulation and lumped formulation in the linear case and the fractional
generalization of the incomplete lumped formulation in the radial case. By
using the Caputo differintegral operator and the Laplace transform, the
solutions are obtained in integral forms where the integrand is expressed in
terms of the convolution of some auxiliary functions of Wright function type. A
generalization of the Laplace transform convolution theorem, known as Efros'
theorem is widely used.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:15:59 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Garg",
"Mridula",
""
],
[
"Rao",
"Alka",
""
]
] |
0707.1975 | R Thangadurai | R Thangadurai | A variant of Davenport's constant | 13 pages | null | null | null | math.NT | null | Let p be a prime number. Let G be a finite abelian p-group of exponent n
(written additively) and A be a non-empty subset of $]n[:= \{1,2,..., n\}$ such
that elements of A are incongruent modulo p and non-zero modulo p. Let $k \geq
D(G)/|A|$ be any integer where D(G) denotes the well-known Davenport's
constant. In this article, we prove that for any sequence g_1, g_2, ..., g_k
(not necessarily distinct) in G, one can always extract a subsequence g_{i_1},
g_{i_2}, ..., g_{i_\ell} with $1\leq \ell \leq k$ such that \begin{equation*}
\sum_{j=1}^\ell a_{j}g_{i_j} = 0 {in} G, \end{equation*} where a_j \in A for
all j. We provide examples where this bound cannot be improved. Furthermore,
for the cyclic groups, we prove some sharp results in this direction. In the
last section, we explore the relation between this problem and a similar
problem with prescribed length. The proof of Theorem~1 uses group-algebra
techniques, while for the other theorems, we use elementary number theory
techniques.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:18:51 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Thangadurai",
"R",
""
]
] |
0707.1976 | Jussi Tyhtila I | Jussi Ilmari Tyhtila | Analytical solution for 3-dimensional, incompressible Navier-Stokes
equations | Replaced with better functions, now explicit pressure obtained via an
external force added | null | null | null | physics.gen-ph | null | This paper provides primarily an analytical ad hoc -solution for
3-dimensional, incompressible Navier-Stokes equations with a suitable external
force field. The solution turns out to be smooth and integrable on the whole
space. There is gaussian decay of amplitudes.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:22:29 GMT"
},
{
"version": "v2",
"created": "Sun, 15 Jul 2007 20:13:25 GMT"
},
{
"version": "v3",
"created": "Wed, 18 Jul 2007 14:49:52 GMT"
},
{
"version": "v4",
"created": "Sat, 21 Jul 2007 08:32:30 GMT"
},
{
"version": "v5",
"created": "Tue, 24 Jul 2007 18:32:35 GMT"
}
] | 2014-02-11T00:00:00 | [
[
"Tyhtila",
"Jussi Ilmari",
""
]
] |
0707.1977 | Levent Kurnaz | E. Gultepe and M. L. Kurnaz | Monte Carlo Simulation and Statistical Analysis of the Effect of Coding
Table Specificity on Genetic Information Coding | null | null | null | null | q-bio.PE q-bio.GN | null | We present a computer simulation, which is inspired by Penna model, to help
understanding the effect of genetic coding tables on population dynamics. To
represent populations we used real and artificial gene sequences in this model.
We coded these sequences using different amino acid tables in Nature, the
standard table as well as the tables which are used by mithocondria and some
eukaryotes. Contrary to common belief we find that the standard code table
which is used in most organisms in Nature, does not give the most resilient
coding against point mutations.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:22:35 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Gultepe",
"E.",
""
],
[
"Kurnaz",
"M. L.",
""
]
] |
0707.1978 | Damien Calaque | Damien Calaque and Gilles Halbout | Weak quantization of Poisson structures | LaTex, 19 pages, 6 figures ; typos corrected and references updated | Journal of Geometry and Physics 61 (2011), no. 8, 1401-1414 | 10.1016/j.geomphys.2011.03.004 | null | math.QA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we prove that any Poisson structure on a sheaf of Lie
algebroids admits a weak deformation quantization, and give a sufficient
condition for such a Poisson structure to admit an actual deformation
quantization. We also answer the corresponding classification problems. In the
complex symplectic case, we recover in particular some results of Nest-Tsygan
and Polesello-Schapira.
We begin the paper with a recollection of known facts about deformation
theory of cosimplicial differential graded Lie algebras.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:46:18 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Nov 2007 18:22:10 GMT"
},
{
"version": "v3",
"created": "Fri, 25 Mar 2011 22:33:39 GMT"
}
] | 2012-01-24T00:00:00 | [
[
"Calaque",
"Damien",
""
],
[
"Halbout",
"Gilles",
""
]
] |
0707.1979 | Christopher Moseley | Ch. Moseley, O. Fialko, K. Ziegler | Interacting bosons in an optical lattice | 58 pages, 14 figures | Ann. Phys. (Berlin) 17, pp. 48 (2008) | 10.1002/andp.20085200804 | null | cond-mat.other | null | Several models of a strongly interacting Bose gas in an optical lattice are
studied within the functional-integral approach. The one-dimensional Bose gas
is briefly discussed. Then the Bose-Einstein condensate and the Mott insulator
of a three-dimensional Bose gas are described in mean-field approximation, and
the corresponding phase diagrams are evaluated. Other characteristic
quantities, like the spectrum of quasiparticle excitations and the static
structure factor, are obtained from Gaussian fluctuations around the mean-field
solutions. We discuss the role of quantum and thermal fluctuations, and
determine the behavior of physical quantities in terms of density and
temperature of the Bose gas. In particular, we study the dilute limit, where
the mean-field equation becomes the Gross-Pitaevskii equation. This allows us
to extend the Gross-Pitaevskii equation to the dense regime by introducing
renormalized parameters in the latter.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:32:34 GMT"
}
] | 2022-06-15T00:00:00 | [
[
"Moseley",
"Ch.",
""
],
[
"Fialko",
"O.",
""
],
[
"Ziegler",
"K.",
""
]
] |
0707.1980 | Tobias Salger | Tobias Salger, Carsten Geckeler, Sebastian Kling, Martin Weitz | Atomic Landau-Zener tunneling in Fourier-synthesized optical lattices | 5 pages, 5 figures | Phys. Rev. Lett. 99, 190405 (2007) | 10.1103/PhysRevLett.99.190405 | null | cond-mat.other | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We report on an experimental study of quantum transport of atoms in variable
periodic optical potentials. The band structure of both ratchet-type asymmetric
and symmetric lattice potentials is explored. The variable atom potential is
realized by superimposing a conventional standing wave potential of \lambda/2
spatial periodicity with a fourth-order multiphoton potential of \lambda /4
periodicity. We find that the Landau-Zener tunneling rate between the first and
the second excited Bloch band depends critically on the relative phase between
the two spatial lattice harmonics.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:38:57 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Nov 2007 08:26:28 GMT"
},
{
"version": "v3",
"created": "Mon, 16 Mar 2009 12:16:01 GMT"
},
{
"version": "v4",
"created": "Fri, 11 Feb 2011 10:12:27 GMT"
},
{
"version": "v5",
"created": "Mon, 28 Feb 2011 15:19:14 GMT"
}
] | 2011-03-01T00:00:00 | [
[
"Salger",
"Tobias",
""
],
[
"Geckeler",
"Carsten",
""
],
[
"Kling",
"Sebastian",
""
],
[
"Weitz",
"Martin",
""
]
] |
0707.1981 | Wojciech Moczydlowski | Wojciech Moczydlowski | A Normalizing Intuitionistic Set Theory with Inaccessible Sets | To be published in Logical Methods in Computer Science | Logical Methods in Computer Science, Volume 3, Issue 3 (August 16,
2007) lmcs:837 | 10.2168/LMCS-3(3:6)2007 | null | cs.LO | null | We propose a set theory strong enough to interpret powerful type theories
underlying proof assistants such as LEGO and also possibly Coq, which at the
same time enables program extraction from its constructive proofs. For this
purpose, we axiomatize an impredicative constructive version of
Zermelo-Fraenkel set theory IZF with Replacement and $\omega$-many
inaccessibles, which we call \izfio. Our axiomatization utilizes set terms, an
inductive definition of inaccessible sets and the mutually recursive nature of
equality and membership relations. It allows us to define a weakly-normalizing
typed lambda calculus corresponding to proofs in \izfio according to the
Curry-Howard isomorphism principle. We use realizability to prove the
normalization theorem, which provides a basis for program extraction
capability.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:02:10 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 15:37:16 GMT"
},
{
"version": "v3",
"created": "Tue, 8 Apr 2008 08:03:51 GMT"
}
] | 2015-07-01T00:00:00 | [
[
"Moczydlowski",
"Wojciech",
""
]
] |
0707.1982 | Andrew R. Liddle | Soo A Kim and Andrew R Liddle | Nflation: observable predictions from the random matrix mass spectrum | 5 pages RevTeX with 4 figures. Minor corrections to match version to
appear in Physical Review D | Phys.Rev.D76:063515,2007 | 10.1103/PhysRevD.76.063515 | null | astro-ph | null | We carry out numerical investigations of the perturbations in Nflation models
where the mass spectrum is generated by random matrix theory. The
tensor-to-scalar ratio and non-gaussianity are already known to take the
single-field values, and so the density perturbation spectral index is the main
parameter of interest. We study several types of random field initial
conditions, and compute the spectral index as a function of mass spectrum
parameters. Comparison with microwave anisotropy data from the Wilkinson
Microwave Anisotropy Probe shows that the model is currently viable in the
majority of its parameter space.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:48:23 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 11:39:06 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Kim",
"Soo A",
""
],
[
"Liddle",
"Andrew R",
""
]
] |
0707.1983 | Yuri Matiyasevich | Yuri Matiyasevich | Hidden Life of Riemann's Zeta Function 1. Arrow, Bow, and Targets | 35 color figures. In version 2: English corrected, URLs updated | null | null | null | math.NT | null | The Riemann Hypothesis is reformulated as statements about eigenvalues of
some matrices entries of which are defined via Taylor coefficient of the zeta
function. These eigenvalues demonstrate interesting visual patterns allowing
one to state a number of conjectures.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 11:55:50 GMT"
},
{
"version": "v2",
"created": "Sat, 29 Sep 2007 07:36:21 GMT"
}
] | 2007-09-29T00:00:00 | [
[
"Matiyasevich",
"Yuri",
""
]
] |
0707.1984 | Charles Bonatto | Charles Bonatto, Eduardo Bica | Old open clusters in the inner Galaxy: FSR1744, FSR89 and FSR31 | 12 pages and 13 figs; A&A, accepted, July 9, 2007 | null | 10.1051/0004-6361:20077675 | null | astro-ph | null | We establish the nature and derive fundamental and structural parameters of
the recently catalogued objects FSR1744, FSR89 and FSR31. This work intends to
provide clues to constrain the Galactic tidal disruption efficiency, improve
statistics of the open cluster parameter space, and better define their
age-distribution function inside the Solar circle. Properties of the objects
are investigated by means of 2MASS colour-magnitude diagrams and stellar radial
density profiles built with field star decontaminated photometry.
Diagnostic-diagrams for structural parameters are used to help disentangle
dynamical from high-background effects affecting such centrally projected open
clusters. FSR1744, FSR89 and FSR31 are Gyr-class OCs located at Galactocentric
distances 4.0 - 5.6kpc. Compared to nearby OCs, they have small core and
limiting radii. With respect to the small number of OCs observed in the inner
Galaxy, the emerging scenario in the near-infrared favours disruption driven by
dynamical evolution rather than observational limitations associated with
absorption and/or high background levels. Internally, the main processes
associated with the dynamical evolution are, e.g. mass loss by stellar
evolution, mass segregation and evaporation. Externally they are, e.g. tidal
stress from the disk and bulge, and interactions with giant molecular clouds.
FSR1744, FSR89 and FSR31 have structural parameters consistent with their
Galactocentric distances, in the sense that tidally induced effects may have
accelerated the dynamical evolution.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:00:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bonatto",
"Charles",
""
],
[
"Bica",
"Eduardo",
""
]
] |
0707.1985 | Ivo Degiovanni | Ivo P. Degiovanni, Maria Bondani, Emiliano Puddu, Alessandra Andreoni,
Matteo G. A. Paris | Intensity correlations, entanglement properties and ghost imaging in
multimode thermal-seeded parametric downconversion: Theory | 9 pages, 3 figures | Phys. Rev. A 76, 062309 (2007) | 10.1103/PhysRevA.76.062309 | null | quant-ph | null | We address parametric-downconversion seeded by multimode pseudo-thermal
fields. We show that this process may be used to generate multimode pairwise
correlated states with entanglement properties that can be tuned by controlling
the seed intensities. Multimode pseudo-thermal fields seeded
parametric-downconversion represents a novel source of correlated states, which
allows one to explore the classical-quantum transition in pairwise correlations
and to realize ghost imaging and ghost diffraction in regimes not yet explored
by experiments.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:51:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Degiovanni",
"Ivo P.",
""
],
[
"Bondani",
"Maria",
""
],
[
"Puddu",
"Emiliano",
""
],
[
"Andreoni",
"Alessandra",
""
],
[
"Paris",
"Matteo G. A.",
""
]
] |
0707.1986 | Frederic Mila | Arnaud Ralko, Michel Ferrero, Federico Becca, Dmitri Ivanov, Frederic
Mila | Crystallization of the resonating valence bond liquid as vortex
condensation | 4 pages, 4 figures | Phys. Rev. B 76, 140404(R) (2007) | 10.1103/PhysRevB.76.140404 | null | cond-mat.str-el | null | We show that the liquid-to-crystal quantum phase transition in the
Rokhsar--Kivelson dimer model on the two-dimensional triangular lattice occurs
as a condensation of vortex-like excitations called ``visons''. This conclusion
is drawn from the numerical studies of the vison spectrum in the liquid phase
by using the Green's function Monte Carlo method. We find that visons remain
the lowest excitation throughout the liquid phase and that their gap decreases
continuously to zero at the phase transition. The nature of the crystal phase
and the second order of the phase transition are in agreement with the earlier
prediction of Moessner and Sondhi [Phys. Rev. B 63, 224401 (2001)].
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:35:52 GMT"
}
] | 2007-10-25T00:00:00 | [
[
"Ralko",
"Arnaud",
""
],
[
"Ferrero",
"Michel",
""
],
[
"Becca",
"Federico",
""
],
[
"Ivanov",
"Dmitri",
""
],
[
"Mila",
"Frederic",
""
]
] |
0707.1987 | Massimo D'Elia | Simone Conradi and Massimo D'Elia | Imaginary chemical potentials and the phase of the fermionic determinant | 6 pages, 6 figures | Phys.Rev.D76:074501,2007 | 10.1103/PhysRevD.76.074501 | GEF-TH 18/07 | hep-lat | null | A numerical technique is proposed for an efficient numerical determination of
the average phase factor of the fermionic determinant continued to imaginary
values of the chemical potential. The method is tested in QCD with eight
flavors of dynamical staggered fermions. A direct check of the validity of
analytic continuation is made on small lattices and a study of the scaling with
the lattice volume is performed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 19:56:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Conradi",
"Simone",
""
],
[
"D'Elia",
"Massimo",
""
]
] |
0707.1988 | Bolek Pietrzyk | B. Pietrzyk | LHCb detector status and commissioning | HCP06 proceedings for references | null | null | null | physics.ins-det | null | The LHCb detector status and commissioning is presented.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:40:19 GMT"
}
] | 2009-11-23T00:00:00 | [
[
"Pietrzyk",
"B.",
""
]
] |
0707.1989 | Karsten Flensberg | Anders Mathias Lunde, Alessandro De Martino, Reinhold Egger, and
Karsten Flensberg | Electron-electron interaction effects in quantum point contacts | 4 pages | null | null | null | cond-mat.mes-hall | null | We consider interaction effects in quantum point contacts on the first
quantization plateau, taking into account all non momentum-conserving
processes. We compute low-temperature linear and non-linear conductance, shot
noise, and thermopower by perturbation theory, and show that they are
consistent with experimental observations on the so-called "0.7 anomaly". The
full temperature-dependent conductance is obtained from self-consistent
second-order perturbation theory and approaches ~ e^2/h at higher temperatures,
but still smaller than the Fermi temperature.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:05:27 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Lunde",
"Anders Mathias",
""
],
[
"De Martino",
"Alessandro",
""
],
[
"Egger",
"Reinhold",
""
],
[
"Flensberg",
"Karsten",
""
]
] |
0707.1990 | Lucas Lacasa | Bartolo Luque, Lucas Lacasa, Octavio Miramontes | Phase transition in a stochastic prime number generator | accepted in PRE (Rapid Comm.) | Physical Review E 76, 010103 (R) (2007) | 10.1103/PhysRevE.76.010103 | null | physics.comp-ph | null | We introduce a stochastic algorithm that acts as a prime number generator.
The dynamics of such algorithm gives rise to a continuous phase transition
which separates a phase where the algorithm is able to reduce a whole set of
integers into primes and a phase where the system reaches a frozen state with
low prime density. We present both numerical simulations and an analytical
approach in terms of an annealed approximation, by means of which the data are
collapsed. A critical slowing down phenomenon is also outlined.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:44:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Luque",
"Bartolo",
""
],
[
"Lacasa",
"Lucas",
""
],
[
"Miramontes",
"Octavio",
""
]
] |
0707.1991 | Michel L. E. Rieutord | M. Rieutord, T. Roudier, S. Roques and C. Ducottet | Tracking granules on the Sun's surface and reconstructing horizontal
velocity fields: I. the CST algorithm | in press in Astronomy and Astrophysics, 9 pages | null | 10.1051/0004-6361:20066491 | null | astro-ph | null | Determination of horizontal velocity fields on the solar surface is crucial
for understanding the dynamics of structures like mesogranulation or
supergranulation or simply the distribution of magnetic fields.
We pursue here the development of a method called CST for coherent structure
tracking, which determines the horizontal motion of granules in the field of
view.
We first devise a generalization of Strous method for the segmentation of
images and show that when segmentation follows the shape of granules more
closely, granule tracking is less effective for large granules because of
increased sensitivity to granule fragmentation. We then introduce the
multi-resolution analysis on the velocity field, based on Daubechies wavelets,
which provides a view of this field on different scales. An algorithm for
computing the field derivatives, like the horizontal divergence and the
vertical vorticity, is also devised. The effects from the lack of data or from
terrestrial atmospheric distortion of the images are also briefly discussed.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:44:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rieutord",
"M.",
""
],
[
"Roudier",
"T.",
""
],
[
"Roques",
"S.",
""
],
[
"Ducottet",
"C.",
""
]
] |
0707.1992 | Attila Szolnoki | Matjaz Perc and Attila Szolnoki | Noise-guided evolution within cyclical interactions | to be published in New J. Phys | New J. Phys. 9 (2007) 267 | 10.1088/1367-2630/9/8/267 | null | q-bio.PE cond-mat.stat-mech physics.bio-ph | null | We study a stochastic predator-prey model on a square lattice, where each of
the six species has two superior and two inferior partners. The invasion
probabilities between species depend on the predator-prey pair and are
supplemented by Gaussian noise. Conditions are identified that warrant the
largest impact of noise on the evolutionary process, and the results of Monte
Carlo simulations are qualitatively reproduced by a four-point cluster
dynamical mean-field approximation. The observed noise-guided evolution is
deeply routed in short-range spatial correlations, which is supported by
simulations on other host lattice topologies. Our findings are conceptually
related to the coherence resonance phenomenon in dynamical systems via the
mechanism of threshold duality. We also show that the introduced concept of
noise-guided evolution via the exploitation of threshold duality is not limited
to predator-prey cyclical interactions, but may apply to models of evolutionary
game theory as well, thus indicating its applicability in several different
fields of research.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:45:08 GMT"
}
] | 2007-08-25T00:00:00 | [
[
"Perc",
"Matjaz",
""
],
[
"Szolnoki",
"Attila",
""
]
] |
0707.1993 | Doron Cohen | Doron Cohen and Baruch Horovitz | Decoherence of a particle in a ring | 5 pages, 1 figure, proofed version to be published in EPL | Europhysics Letters 81, 30001 (2008) | 10.1209/0295-5075/81/30001 | null | cond-mat.mes-hall | null | We consider a particle coupled to a dissipative environment and derive a
perturbative formula for the dephasing rate based on the purity of the reduced
probability matrix. We apply this formula to the problem of a particle on a
ring, that interacts with a dirty metal environment. At low but finite
temperatures we find a dephasing rate $\propto T^{3/2}$, and identify dephasing
lengths for large and for small rings. These findings shed light on recent
Monte Carlo data regarding the effective mass of the particle. At zero
temperature we find that spatial fluctuations suppress the possibility of
having a power law decay of coherence.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:50:48 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 07:51:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cohen",
"Doron",
""
],
[
"Horovitz",
"Baruch",
""
]
] |
0707.1994 | Michel L. E. Rieutord | R. Tkaczuk, M. Rieutord, N. Meunier and T. Roudier | Tracking granules at the Sun's surface and reconstructing velocity
fields. II. Error analysis | in press in Astronomy and Astrophysics, 9 pages | null | 10.1051/0004-6361:20066492 | null | astro-ph | null | The determination of horizontal velocity fields at the solar surface is
crucial to understanding the dynamics and magnetism of the convection zone of
the sun. These measurements can be done by tracking granules.
Tracking granules from ground-based observations, however, suffers from the
Earth's atmospheric turbulence, which induces image distortion. The focus of
this paper is to evaluate the influence of this noise on the maps of velocity
fields.
We use the coherent structure tracking algorithm developed recently and apply
it to two independent series of images that contain the same solar signal.
We first show that a k-\omega filtering of the times series of images is
highly recommended as a pre-processing to decrease the noise, while, in
contrast, using destretching should be avoided. We also demonstrate that the
lifetime of granules has a strong influence on the error bars of velocities and
that a threshold on the lifetime should be imposed to minimize errors. Finally,
although solar flow patterns are easily recognizable and image quality is very
good, it turns out that a time sampling of two images every 21 s is not
frequent enough, since image distortion still pollutes velocity fields at a 30%
level on the 2500 km scale, i.e. the scale on which granules start to behave
like passive scalars.
The coherent structure tracking algorithm is a useful tool for noise control
on the measurement of surface horizontal solar velocity fields when at least
two independent series are available.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:57:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tkaczuk",
"R.",
""
],
[
"Rieutord",
"M.",
""
],
[
"Meunier",
"N.",
""
],
[
"Roudier",
"T.",
""
]
] |
0707.1995 | Jean Michel Maillet | N. Kitanine, K.K. Kozlowski, J.M. Maillet, G. Niccoli, N.A. Slavnov,
V. Terras | Correlation functions of the open XXZ chain I | 44 pages | J.Stat.Mech.0710:P10009,2007 | 10.1088/1742-5468/2007/10/P10009 | null | hep-th | null | We consider the XXZ spin chain with diagonal boundary conditions in the
framework of algebraic Bethe Ansatz. Using the explicit computation of the
scalar products of Bethe states and a revisited version of the bulk inverse
problem, we calculate the elementary building blocks for the correlation
functions. In the limit of half-infinite chain, they are obtained as multiple
integrals of usual functions, similar to the case of periodic boundary
conditions.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:58:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kitanine",
"N.",
""
],
[
"Kozlowski",
"K. K.",
""
],
[
"Maillet",
"J. M.",
""
],
[
"Niccoli",
"G.",
""
],
[
"Slavnov",
"N. A.",
""
],
[
"Terras",
"V.",
""
]
] |
0707.1996 | Abey L\'opez Garc\'ia | Abey L\'opez Garc\'ia and Guillermo L\'opez Lagomasino | Ratio Asymptotic of Hermite-Pad\'e Orthogonal Polynomials for Nikishin
Systems. II | 24 pages, 2 tables | Adv. Math. 218 (2008), 1081-1106 | null | null | math.CV | null | We prove ratio asymptotic for sequences of multiple orthogonal polynomials
with respect to a Nikishin system of measures
${\mathcal{N}}(\sigma_1,...,\sigma_m)$ such that for each $k$, the support of
$\sigma_k$ consists of an interval $\widetilde{\Delta}_k$, on which
$\sigma_k^{\prime} > 0$ almost everywhere, and a set without accumulation
points in $\mathbb{R} \setminus \widetilde{\Delta}_k$.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 12:59:29 GMT"
}
] | 2019-10-22T00:00:00 | [
[
"García",
"Abey López",
""
],
[
"Lagomasino",
"Guillermo López",
""
]
] |
0707.1997 | Marat Siddikov Ilfatovich | K. Goeke, M.M. Musakhanov, M. Siddikov | Low energy constants of \chiPT from the instanton vacuum model | null | Phys.Rev.D76:076007,2007 | 10.1103/PhysRevD.76.076007 | null | hep-ph | null | In the framework of the instanton vacuum model we make expansion over the
current mass m and number of colors N_c and evaluate ${\cal O}(1/N_c, m, m/N_c,
m \ln m/N_c)$-corrections to the dynamical quark mass M, the quark condensate
$<\bar qq>$, the pion mass M_\pi and decay constant F_\pi. There are several
sources of these corrections: meson loops, finite size of the instanton
distribution and the quark-quark "tensor" interaction terms. In contrast to the
expectations, we found that numerically the 1/N_c-corrections to dynamical mass
are large and mostly come from meson loops. As a consequence, we have large
1/N_c-corrections to all the other quantities. To provide the values of
$F_\pi(m=0), \ave{\bar qq(m=0)}$ in agreement with \chiPT, we offer a new set
of parameters \rho, R. Finally, we find the low-energy SU(2)_f chiral
lagrangian constants $\bar l_3, \bar l_4$ in a rather good correspondence with
the phenomenology.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:00:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Goeke",
"K.",
""
],
[
"Musakhanov",
"M. M.",
""
],
[
"Siddikov",
"M.",
""
]
] |
0707.1998 | Alessandro Mirizzi | G.L.Fogli, E.Lisi, A.Marrone (Bari U. & INFN, Bari), A.Mirizzi
(Munich, Max Planck Institut & Bari U. & INFN, Bari) | Collective neutrino flavor transitions in supernovae and the role of
trajectory averaging | v2 (27 pages, including 9 eps figures). Typos removed, references
updated. Minor comments added. Corrected numerical errors in Eq.(6). Matches
the published version | JCAP 0712:010,2007 | 10.1088/1475-7516/2007/12/010 | MPP-2007-54 | hep-ph astro-ph | null | Non-linear effects on supernova neutrino oscillations, associated with
neutrino self-interactions, are known to induce collective flavor transitions
near the supernova core for theta_13 \neq 0. In scenarios with very shallow
electron density profiles, these transformations have been shown to couple with
ordinary matter effects, jointly producing spectral distortions both in normal
and inverted hierarchy. In this work we consider a complementary scenario,
characterized by higher electron density, as indicated by post-bounce
shock-wave simulations. In this case, early collective flavor transitions are
decoupled from later, ordinary matter effects. Moreover, such transitions
become more amenable to both numerical computations and analytical
interpretations in inverted hierarchy, while they basically vanish in normal
hierarchy. We numerically evolve the neutrino density matrix in the region
relevant for self-interaction effects. In the approximation of averaged
intersection angle between neutrino trajectories, our simulations neatly show
the collective phenomena of synchronization, bipolar oscillations, and spectral
split, recently discussed in the literature. In the more realistic (but
computationally demanding) case of non-averaged neutrino trajectories, our
simulations do not show new significant features, apart from the smearing of
``fine structures'' such as bipolar nutations. Our results seem to suggest
that, at least for non-shallow matter density profiles, averaging over neutrino
trajectories plays a minor role in the final outcome. In this case, the swap of
nu_e and nu_{\mu,\tau} spectra above a critical energy may represent an
unmistakable signature of the inverted hierarchy, especially for theta_{13}
small enough to render further matter effects irrelevant.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:17:21 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Dec 2007 13:36:08 GMT"
}
] | 2009-10-07T00:00:00 | [
[
"Fogli",
"G. L.",
"",
"Bari U. & INFN, Bari"
],
[
"Lisi",
"E.",
"",
"Bari U. & INFN, Bari"
],
[
"Marrone",
"A.",
"",
"Bari U. & INFN, Bari"
],
[
"Mirizzi",
"A.",
"",
"Munich, Max Planck Institut & Bari U. & INFN, Bari"
]
] |
0707.1999 | Bernhard Hanke | B. Hanke, D. Kotschick, J. Roe, T. Schick | Coarse topology, enlargeability, and essentialness | 21 pages, 2 figures. Revised version. To appear in Ann. Sci. Ecole
Norm. Sup | Ann. Sci. Ecole Norm. Sup. 41 (2008), 471--493 | 10.24033/asens.2073 | null | math.AT math.DG math.GT math.KT | null | Using methods from coarse topology we show that fundamental classes of closed
enlargeable manifolds map non-trivially both to the rational homology of their
fundamental groups and to the K-theory of the corresponding reduced
C*-algebras. Our proofs do not depend on the Baum--Connes conjecture and
provide independent confirmation for specific predictions derived from this
conjecture.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 17:07:47 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Mar 2008 14:26:44 GMT"
}
] | 2018-11-28T00:00:00 | [
[
"Hanke",
"B.",
""
],
[
"Kotschick",
"D.",
""
],
[
"Roe",
"J.",
""
],
[
"Schick",
"T.",
""
]
] |
0707.2000 | Fan Wu M. S. | Fan Wu, Leif Roschier, Taku Tsuneta, Mikko Paalanen, Taihong Wang,
Pertti Hakonen | Setup for shot noise measurements in carbon nanotubes | 2 pages, 2 figures, published on AIP conference proceedings 2006 | AIP Conference Proceedings 850 (ISBN 0-7354-0347-3), pp 1482-1483,
2006 | 10.1063/1.2355263 | null | cond-mat.mes-hall | null | We have constructed a noise measurement setup for high impedance carbon
nanotube samples. Our setup, working in the frequency range of 600 - 900 MHz,
takes advantage of the fact that the shot noise power is reasonably large for
high impedance sources so that relatively large, fixed non-matching conditions
can be tolerated.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:21:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wu",
"Fan",
""
],
[
"Roschier",
"Leif",
""
],
[
"Tsuneta",
"Taku",
""
],
[
"Paalanen",
"Mikko",
""
],
[
"Wang",
"Taihong",
""
],
[
"Hakonen",
"Pertti",
""
]
] |
0707.2001 | Stephane Toulin | Yves Garrabos (ICMCB), Fabien Palencia (ICMCB), Carole Lecoutre-Chabot
(ICMCB), Daniel Broseta (TEFC), Bernard Le Neindre (LIMHP) | Master crossover behavior of parachor correlations for one-component
fluids | null | Physical Review E: Statistical, Nonlinear, and Soft Matter Physics
76, 6 (2007) 061109 (22 p.) | 10.1103/PhysRevE.76.061109 | null | cond-mat.stat-mech | null | The master asymptotic behavior of the usual parachor correlations, expressing
surface tension $\sigma$ as a power law of the density difference
$\rho_{L}-\rho_{V}$ between coexisting liquid and vapor, is analyzed for a
series of pure compounds close to their liquid-vapor critical point, using only
four critical parameters $(\beta_{c})^{-1}$, $\alpha_{c}$, $Z_{c}$ and $Y_{c}$,
for each fluid.
... The main consequences of these theoretical estimations are discussed in
the light of engineering applications and process simulations where parachor
correlations constitute one of the most practical method for estimating surface
tension from density and capillary rise measurements.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:24:14 GMT"
}
] | 2007-12-11T00:00:00 | [
[
"Garrabos",
"Yves",
"",
"ICMCB"
],
[
"Palencia",
"Fabien",
"",
"ICMCB"
],
[
"Lecoutre-Chabot",
"Carole",
"",
"ICMCB"
],
[
"Broseta",
"Daniel",
"",
"TEFC"
],
[
"Neindre",
"Bernard Le",
"",
"LIMHP"
]
] |
0707.2002 | Enrique Batista | Ping Yang, Enrique R. Batista, Sergei Tretiak, Avadh Saxena, Richard
L. Martin, and D. L. Smith | Effect of Intra-molecular Disorder and Inter-molecular Electronic
Interactions on the Electronic Structure of Poly-p-Phenylene Vinylene (PPV) | 4 pages, 4 figures. Compile with pdflatex | null | 10.1103/PhysRevB.76.241201 | null | cond-mat.soft cond-mat.mtrl-sci | null | We investigate the role of intra-molecular conformational disorder and
inter-molecular electronic interactions on the electronic structure of disorder
clusters of poly-p-phenylene vinylene (PPV) oligomers. Classical molecular
dynamics is used to determine probable molecular geometries, and
first-principle density functional theory (DFT) calculations are used to
determine electronic structure. Intra-molecular and inter-molecular effects are
disentangled by contrasting results for densely packed oligomer clusters with
those for ensembles of isolated oligomers with the same intra-molecular
geometries. We find that electron trap states are induced primarily by
intra-molecular configuration disorder, while the hole trap states are
generated primarily from inter-molecular electronic interactions.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 17:13:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yang",
"Ping",
""
],
[
"Batista",
"Enrique R.",
""
],
[
"Tretiak",
"Sergei",
""
],
[
"Saxena",
"Avadh",
""
],
[
"Martin",
"Richard L.",
""
],
[
"Smith",
"D. L.",
""
]
] |
0707.2003 | Benjamin Webster | Ben Webster, Geordie Williamson | A geometric model for Hochschild homology of Soergel bimodules | 19 pages, no figures | Geom. Topol. 12 (2008) 1243-1263 | 10.2140/gt.2008.12.1243 | null | math.AG math.RT | null | An important step in the calculation of the triply graded link homology
theory of Khovanov and Rozansky is the determination of the Hochschild homology
of Soergel bimodules for SL(n). We present a geometric model for this
Hochschild homology for any simple group G, as equivariant intersection
homology of B x B-orbit closures in G. We show that, in type A these orbit
closures are equivariantly formal for the conjugation T-action. We use this
fact to show that in the case where the corresponding orbit closure is smooth,
this Hochschild homology is an exterior algebra over a polynomial ring on
generators whose degree is explicitly determined by the geometry of the orbit
closure, and describe its Hilbert series, proving a conjecture of Jacob
Rasmussen.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 17:08:08 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Aug 2007 21:33:45 GMT"
}
] | 2014-11-11T00:00:00 | [
[
"Webster",
"Ben",
""
],
[
"Williamson",
"Geordie",
""
]
] |
0707.2004 | Javier Vasquez | C. Cappa (1,2), V.S. Niemela (1,3), R. Amorin (4) and J. Vasquez
(1,2); ((1) Facultad de Ciencias Astronomicas y Geofisicas, Universidad
Nacional de La Plata, La Plata, Argentina; (2) Instituto Argentino de
Radioastronomia, Villa Elisa, Argentina; (3) Instituto de Astrofisica de La
Plata, La Plata, Argentina; (4) Instituto de Astrofisica de Canarias, Spain) | The environs of the HII region Gum31 | submitted to A&A, 12 pages, 10 figures, 3 tables | null | null | null | astro-ph | null | We analyze the distribution of the interstellar matter in the environs of the
\hii region Gum 31, excited by the open cluster NGC 3324, located in the
complex Carina region, with the aim of investigating the action of the massive
stars on the surrounding neutral material. We use 21cm-line data, radio
continuum images at 0.843, 2.4 and 4.9 GHz, $^{12}${\bf CO(1-0)} observations,
and IRAS and MSX infrared data. Adopting a distance of 3 kpc for the \hii\
region and the ionizing cluster, we have derived an electron density of
33$\pm$3 cm$^{-3}$ and an ionized mass of (3.3$\pm$1.1)$\times10^3$ M$_{\odot}$
based on the radio continuum data at 4.9 GHz. The \hi 21-cm line images
revealed an \hi shell surrounding the H {\sc ii} region. The \hi structure is
10.0$\pm$1.7 pc in radius, has a neutral mass of 1500$\pm$500 M$_{\odot}$, and
is expanding at 11 km s$^{-1}$. The associated molecular gas amounts to
(1.5$\pm$0.5)$\times10^5$ M$_{\odot}$, being its volume density of about 500
cm^{-3}. This molecular material probably represents the remains of the cloud
where the young open cluster NGC 3324 was born. The distributions of the
ionized and molecular material, along with that of the emission in the MSX band
A suggest that a photodissociation region has developed at the interface
between the ionized and molecular gas. We conclude that either the massive
stars in the open cluster have weak stellar winds or the stellar winds have
blown during a very short period of time to create an interstellar bubble in an
interstellar medium as dense as observed. IRAS, MSX, and 2MASS point sources
projected onto the molecular envelope are compatible with protostellar
candidates, showing the presence star forming regions. The expansion of the
\hii region has triggered stellar formation in the molecular shell.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:59:58 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Cappa",
"C.",
""
],
[
"Niemela",
"V. S.",
""
],
[
"Amorin",
"R.",
""
],
[
"Vasquez",
"J.",
""
],
[
";",
"",
""
]
] |
0707.2005 | Michael De Becker | M. De Becker, G. Rauw, J. M. Pittard, H. Sana, I. R. Stevens, G. E.
Romero | INTEGRAL-ISGRI observations of the CygOB2 region: earching for hard
X-ray point sources in a region containing several non-thermal emitting
massive stars | 6 page, 2 figures including one figure in GIF format, accepted for
publication by A&A | null | 10.1051/0004-6361:20077734 | null | astro-ph | null | Aims: We analyze INTEGRAL-ISGRI data in order to probe the hard X-ray
emission (above 20 keV) from point sources in the Cyg OB2 region and to
investigate the putative non-thermal high-energy emission from early-type stars
(Wolf-Rayet and O-type stars). Among the targets located in the field of view,
we focus on the still unidentified EGRET source 3EG 2033+4118 that may be
related to massive stars known to produce non-thermal emission in the radio
domain, and on the wide colliding-wind binary WR 140. Methods: Using a large
set of data obtained with the IBIS-ISGRI imager onboard INTEGRAL, we run the
OSA software package in order to find point sources in the fully coded field of
view of the instrument. Results: Our data do not allow the detection of a
lower-energy counterpart of 3EG J2033+4118 nor of any other new point sources
in the field of view, and we derive upper limits on the high-energy flux for a
few targets: 3EG J2033+4118, TeV J2032+4130, WR140, WR146 and WR147. The
results are discussed in the context of the multiwavelength investigation of
these objects. Conclusions: The upper limits derived are valuable constraints
for models aimed at understanding the acceleration of particles in non-thermal
emitting massive stars, and of the still unidentified very-high gamma-ray
source TeV J2032+4130.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:37:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"De Becker",
"M.",
""
],
[
"Rauw",
"G.",
""
],
[
"Pittard",
"J. M.",
""
],
[
"Sana",
"H.",
""
],
[
"Stevens",
"I. R.",
""
],
[
"Romero",
"G. E.",
""
]
] |
0707.2006 | Damien Chablat | Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN) | Working Modes and Aspects in Fully-Parallel Manipulator | null | Proceeding IEEE International Conference on Robotics and
Automation (05/1998) 1964-1969 | null | null | cs.RO | null | The aim of this paper is to characterize the notion of aspect in the
workspace and in the joint space for parallel manipulators. In opposite to the
serial manipulators, the parallel manipulators can admit not only multiple
inverse kinematic solutions, but also multiple direct kinematic solutions. The
notion of aspect introduced for serial manipulators in [Borrel 86], and
redefined for parallel manipulators with only one inverse kinematic solution in
[Wenger 1997], is redefined for general fully parallel manipulators. Two
Jacobian matrices appear in the kinematic relations between the joint-rate and
the Cartesian-velocity vectors, which are called the "inverse kinematics" and
the "direct kinematics" matrices. The study of these matrices allow to
respectively define the parallel and the serial singularities. The notion of
working modes is introduced to separate inverse kinematic solutions. Thus, we
can find out domains of the workspace and the joint space exempt of
singularity. Application of this study is the moveability analysis in the
workspace of the manipulator as well as path-planing and control. This study is
illustrated in this paper with a RR-RRR planar parallel manipulator.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:40:56 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
]
] |
0707.2007 | Lazhar Dhaouadi | Lazhar Dhaouadi | Functions of q-positive type | null | Positivity 16 (2012) 107-129 | 10.1007/s11117-011-0115-y | null | math.CA | null | In this paper we characterize the subspace of $\mathcal{L}_{q,1,v}$ of
function which are the q-Bessel Fourier transform of positive functions in
$\mathcal{L}_{q,1,v}$. As application we give a q-version of the Bochner's
theorem.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:44:01 GMT"
}
] | 2013-05-14T00:00:00 | [
[
"Dhaouadi",
"Lazhar",
""
]
] |
0707.2008 | Carlos Cabrelli | Akram Aldroubi, Carlos Cabrelli and Ursula Molter | Optimal Non-Linear Models for Sparsity and Sampling | 20 pages, 2 figures. Final version of the paper. To appear in Journal
of Fourier Analysis and Applications | null | null | null | math.CA | null | Given a set of vectors (the data) in a Hilbert space H, we prove the
existence of an optimal collection of subspaces minimizing the sum of the
square of the distances between each vector and its closest subspace in the
collection. This collection of subspaces gives the best sparse representation
for the given data, in a sense defined in the paper, and provides an optimal
model for sampling in union of subspaces. The results are proved in a general
setting and then applied to the case of low dimensional subspaces of R^N and to
infinite dimensional shift-invariant spaces in L^2(R^d). We also present an
iterative search algorithm for finding the solution subspaces. These results
are tightly connected to the new emergent theories of compressed sensing and
dictionary design, signal models for signals with finite rate of innovation,
and the subspace segmentation problem.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:46:27 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 02:42:46 GMT"
}
] | 2008-02-07T00:00:00 | [
[
"Aldroubi",
"Akram",
""
],
[
"Cabrelli",
"Carlos",
""
],
[
"Molter",
"Ursula",
""
]
] |
0707.2009 | John Moriarty | Yan Doumerc and John Moriarty | Exit problems associated with affine reflection groups | 34 pages. Rewritten in some places to improve presentation. To appear
in Probability Theory and Related Fields | Probability Theory and Related Fields 145 (3-4), pp 351-383 (2009) | 10.1007/s00440-008-0171-9 | null | math.PR math.GR | null | We obtain a formula for the distribution of the first exit time of Brownian
motion from the alcove of an affine Weyl group. In most cases the formula is
expressed compactly, in terms of Pfaffians. Expected exit times are derived in
the type \~A case. The results extend to other Markov processes. We also give
formulas for the real eigenfunctions of the Dirichlet and Neumann Laplacians on
alcoves, observing that the `Hot Spots' conjecture of J. Rauch is true for
alcoves.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 18:03:39 GMT"
},
{
"version": "v2",
"created": "Sun, 25 May 2008 20:17:09 GMT"
}
] | 2013-02-12T00:00:00 | [
[
"Doumerc",
"Yan",
""
],
[
"Moriarty",
"John",
""
]
] |
0707.2010 | Giancarlo Ferrera | Ugo Aglietti (Rome U. & INFN, Rome), Leonardo Di Giustino (Parma U. &
INFN, Parma), Giancarlo Ferrera (Barcelona U. & Florence U.), Alessandro
Renzaglia (Rome U. & INFN, Rome), Giulia Ricciardi (Naples U. & INFN,
Naples), Luca Trentadue (Parma U. & INFN, Parma) | Threshold Resummation in B --> X_c l nu_l Decays | 24 pages, no figures | Phys.Lett.B653:38-52,2007 | 10.1016/j.physletb.2007.07.041 | ROME1/1455-07, DSF/23/2007 | hep-ph | null | We compute the QCD form factor resumming threshold logarithms in B --> X_c +
l + nu_l decays to next-to-leading logarithmic approximation. We present an
interpolation formula including soft as well as collinear effects softened by
the non-vanishing charm mass.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 17:20:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aglietti",
"Ugo",
"",
"Rome U. & INFN, Rome"
],
[
"Di Giustino",
"Leonardo",
"",
"Parma U. &\n INFN, Parma"
],
[
"Ferrera",
"Giancarlo",
"",
"Barcelona U. & Florence U."
],
[
"Renzaglia",
"Alessandro",
"",
"Rome U. & INFN, Rome"
],
[
"Ricciardi",
"Giulia",
"",
"Naples U. & INFN,\n Naples"
],
[
"Trentadue",
"Luca",
"",
"Parma U. & INFN, Parma"
]
] |
0707.2011 | Negadi Tidjani none | Tidjani Negadi | The genetic code multiplet structure, in one number | 9 pages | Symmetry: Culture and Science, Volume 18, Numbers 2-3, pages
149-160 (2007) | null | null | q-bio.OT | null | The standard genetic code multiplet structure as well as the correct
degeneracies, class by class, are all extracted from the (unique) number 23,
the order of the permutation group of 23 objects.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:58:01 GMT"
}
] | 2008-09-01T00:00:00 | [
[
"Negadi",
"Tidjani",
""
]
] |
0707.2012 | Daniel Azagra | D. Azagra, M. Jimenez-Sevilla, F. Macia | Generalized motion of level sets by functions of their curvatures on
Riemannian manifolds | 34 pages; third version (some misprints have been corrected and one
important example added) | null | null | null | math.AP math.DG | null | We consider the generalized evolution of compact level sets by functions of
their normal vectors and second fundamental forms on a Riemannian manifold M.
The level sets of a function $u:M\to\mathbb{R}$ evolve in such a way whenever u
solves an equation $u_{t}+F(Du, D^{2}u)=0$, for some real function F satisfying
a geometric condition. We show existence and uniqueness of viscosity solutions
to this equation under the assumptions that M has nonnegative curvature, F is
continuous off Du=0, (degenerate) elliptic, and locally invariant by parallel
translation. We then prove that this approach is geometrically consistent,
hence it allows to define a generalized evolution of level sets by very
general, singular functions of their curvatures. For instance, these
assumptions on F are satisfied when F is given by the evolutions of level sets
by their mean curvature (even in arbitrary codimension) or by their positive
Gaussian curvature. We also prove that the generalized evolution is consistent
with the classical motion by the corresponding function of the curvature,
whenever the latter exists. When M is not of nonnegative curvature, the same
results hold if one additionally requires that F is uniformly continuous with
respect to D^2 u. Finally we give some counterexamples showing that several
well known properties of the evolutions in $\mathbb{R}^{n}$ are no longer true
when M has negative sectional curvature.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 13:58:40 GMT"
},
{
"version": "v2",
"created": "Sun, 2 Sep 2007 17:28:51 GMT"
},
{
"version": "v3",
"created": "Mon, 28 Jan 2008 14:41:15 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Azagra",
"D.",
""
],
[
"Jimenez-Sevilla",
"M.",
""
],
[
"Macia",
"F.",
""
]
] |
0707.2013 | Rong-Gen Cai | Rong-Gen Cai, Nobuyoshi Ohta | Deconfinement Transition of AdS/QCD at ${\cal O}(\alpha'^3)$ | Latex, 14 pages; v2: the version to appear in PRD | Phys.Rev.D76:106001,2007 | 10.1103/PhysRevD.76.106001 | KU-TP 013 | hep-th gr-qc hep-ph | null | We study the confinement/deconfinement phase transition of holographic
AdS/QCD models by using Ricci flat $AdS_5$ black holes up to ${\cal
O}(\alpha'^3)$, which corresponds to the $\lambda$ expansion correction in the
dual field theory to $\lambda^{-3/2}$, where $\lambda$ is the 't Hooft coupling
constant. We consider two cases: one is the hard-wall AdS/QCD model where a
small radius region of the $AdS_5$ is removed; the other is the case where one
of spatial coordinates for the $AdS_5$ space is compactified, resulting in
Witten's QCD model in 2+1 dimensions. We find that in the hard-wall AdS/QCD
model, the deconfinement temperature decreases when the $\lambda$ expansion
corrections are taken into account, while in Witten's QCD model, the
deconfinement transition always happens when the ratio of inverse temperature
$\beta$ to the period $\beta_s$ of the compactified coordinate decreases to
one, $\beta/\beta_s=1$, the same as the case without the ${\cal O}(\alpha'^3)$
correction.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 15:31:21 GMT"
},
{
"version": "v2",
"created": "Mon, 24 Sep 2007 13:04:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cai",
"Rong-Gen",
""
],
[
"Ohta",
"Nobuyoshi",
""
]
] |
0707.2014 | Giacomo Como | Giacomo Como, Serdar Yuksel, Sekhar Tatikonda | On the error exponent of variable-length block-coding schemes over
finite-state Markov channels with feedback | null | null | null | null | cs.IT math.IT | null | The error exponent of Markov channels with feedback is studied in the
variable-length block-coding setting. Burnashev's classic result is extended
and a single letter characterization for the reliability function of
finite-state Markov channels is presented, under the assumption that the
channel state is causally observed both at the transmitter and at the receiver
side. Tools from stochastic control theory are used in order to treat channels
with intersymbol interference. In particular the convex analytical approach to
Markov decision processes is adopted to handle problems with stopping time
horizons arising from variable-length coding schemes.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:27:26 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Como",
"Giacomo",
""
],
[
"Yuksel",
"Serdar",
""
],
[
"Tatikonda",
"Sekhar",
""
]
] |
0707.2015 | Jan Kleinert | J. Kleinert, C. Haimberger, P. J. Zabawa, and N. P. Bigelow | Trapping of ultracold polar molecules with a Thin Wire Electrostatic
Trap | 4 pages, 3 figures | null | 10.1103/PhysRevLett.99.143002 | null | physics.atom-ph | null | We describe the realization of a dc electric-field trap for ultracold polar
molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form
the electrodes of the TWIST allow us to superimpose the trap onto a
magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules
in their electronic ground state are created in the MOT via photoassociation,
achieving a continuous accumulation in the TWIST of molecules in low-field
seeking states. Initial measurements show that the TWIST trap lifetime is
limited only by the background pressure in the chamber.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:11:18 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 18:04:36 GMT"
}
] | 2007-10-04T00:00:00 | [
[
"Kleinert",
"J.",
""
],
[
"Haimberger",
"C.",
""
],
[
"Zabawa",
"P. J.",
""
],
[
"Bigelow",
"N. P.",
""
]
] |
0707.2016 | Claire Moutou | C. Moutou, J.-F. Donati, R. Savalle, G. Hussain, E. Alecian, F.
Bouchy, C. Catala, A. Collier Cameron, S. Udry, A. Vidal-Madjar | Spectropolarimetric observations of the transiting planetary system of
the K dwarf HD 189733 | Accepted in Astronomy and Astrophysics, 12 pages | null | 10.1051/0004-6361:20077795 | null | astro-ph | null | With a Jupiter-mass planet orbiting at a distance of only 0.031 AU, the
active K2 dwarf HD 189733 is a potential candidate in which to study the
magnetospheric interactions of a cool star with its recently-discovered
close-orbiting giant planet. We decided to explore the strength and topology of
the large-scale magnetosphere of HD 189733, as a future benchmark for
quantitative studies for models of the star/planet magnetic interactions. To
this end, we used ESPaDOnS, the new generation spectropolarimeter at the
Canada-France-Hawaii 3.6m telescope, to look for Zeeman circular polarisation
signatures in the line profiles of HD 189733 in 2006 June and August. Zeeman
signatures in the line profiles of HD 189733 are clearly detected in all
spectra, demonstrating that a field is indeed present at the surface of the
star. The Zeeman signatures are not modulated with the planet's orbital period
but apparently vary with the stellar rotation cycle. The reconstructed
large-scale magnetic field, whose strength reaches a few tens of G, is
significantly more complex than that of the Sun; it involves in particular a
significant toroidal component and contributions from magnetic multipoles of
order up to 5. The CaII H & K lines clearly feature core emission, whose
intensity is apparently varying mostly with rotation phase. Our data suggest
that the photosphere and magnetic field of HD 189733 are sheared by a
significant amount of differential rotation. Our initial study confirms that HD
189733 is an optimal target for investigating activity enhancements induced by
closely orbiting planets. More data are needed, densely covering both the
orbital and rotation cycles, to investigate whether and how much the planet
contributes to the overall activity level of HD 189733.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:14:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Moutou",
"C.",
""
],
[
"Donati",
"J. -F.",
""
],
[
"Savalle",
"R.",
""
],
[
"Hussain",
"G.",
""
],
[
"Alecian",
"E.",
""
],
[
"Bouchy",
"F.",
""
],
[
"Catala",
"C.",
""
],
[
"Cameron",
"A. Collier",
""
],
[
"Udry",
"S.",
""
],
[
"Vidal-Madjar",
"A.",
""
]
] |
0707.2017 | Damien Chablat | Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN), Jorge Angeles (CIM) | The Isoconditioning Loci of A Class of Closed-Chain Manipulators | null | Proceeding IEEE International Conference on Robotics and
Automation (05/1998) 1970-1976 | null | null | cs.RO | null | The subject of this paper is a special class of closed-chain manipulators.
First, we analyze a family of two-degree-of-freedom (dof) five-bar planar
linkages. Two Jacobian matrices appear in the kinematic relations between the
joint-rate and the Cartesian-velocity vectors, which are called the ``inverse
kinematics" and the "direct kinematics" matrices. It is shown that the loci of
points of the workspace where the condition number of the direct-kinematics
matrix remains constant, i.e., the isoconditioning loci, are the coupler points
of the four-bar linkage obtained upon locking the middle joint of the linkage.
Furthermore, if the line of centers of the two actuated revolutes is used as
the axis of a third actuated revolute, then a three-dof hybrid manipulator is
obtained. The isoconditioning loci of this manipulator are surfaces of
revolution generated by the isoconditioning curves of the two-dof manipulator,
whose axis of symmetry is that of the third actuated revolute.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:18:45 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
],
[
"Angeles",
"Jorge",
"",
"CIM"
]
] |
0707.2018 | Remon Cornelisse | R. Cornelisse, D. Steeghs, J. Casares, P.A. Charles, I.C. Shih, R.I.
Hynes, K. O'Brien | A signature of the donor star in the extra-galactic X-ray binary LMC X-2 | 9 pages, 7 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12233.x | null | astro-ph | null | Two nights of phase-resolved medium resolution VLT spectroscopy of the
extra-galactic low mass X-ray binary LMC X-2 have revealed a 0.32+/-0.02 day
spectroscopic period in the radial velocity curve of the HeII lambda4686
emission line that we interpret as the orbital period. However, similar to
previous findings, this radial velocity curve shows a longer term variation
that is most likely due to the presence of a precessing accretion disk in LMC
X-2. This is strengthened by HeII lambda4686 Doppler maps that show a bright
spot that is moving from night to night. Furthermore, we detect narrow emission
lines in the Bowen region of LMC X-2,with a velocity of K_em=351+/-28 km/s,
that we tentatively interpret as coming from the irradiated side of the donor
star. Since K_em must be smaller than K_2, this leads to the first upper-limit
on the mass function of LMC X-2 of f(M_1)>=0.86Msun (95% confidence), and the
first constraints on its system parameters.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:21:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cornelisse",
"R.",
""
],
[
"Steeghs",
"D.",
""
],
[
"Casares",
"J.",
""
],
[
"Charles",
"P. A.",
""
],
[
"Shih",
"I. C.",
""
],
[
"Hynes",
"R. I.",
""
],
[
"O'Brien",
"K.",
""
]
] |
0707.2019 | Juan Carlos Martinez Oliveros JCMO | J.C. Martinez-Oliveros, H. Moradi, D. Besliu-Ionescu, A.-C Donea, P.S.
Cally, C. Lindsey | From GHz to mHz: A Multiwavelength Study of the Acoustically Active 14
August 2004 M7.4 Solar Flare | Accepted in Solar Physics | null | 10.1007/s11207-007-9004-8 | null | astro-ph | null | We carried out an electromagnetic acoustic analysis of the solar flare of 14
August 2004 in active region AR10656 from the radio to the hard X-ray spectrum.
The flare was a GOES soft X-ray class M7.4 and produced a detectable sun quake,
confirming earlier inferences that relatively low-energy flares may be able to
generate sun quakes. We introduce the hypothesis that the seismicity of the
active region is closely related to the heights of coronal magnetic loops that
conduct high-energy particles from the flare. In the case of relatively short
magnetic loops, chromospheric evaporation populates the loop interior with
ionized gas relatively rapidly, expediting the scattering of remaining trapped
high-energy electrons into the magnetic loss cone and their rapid precipitation
into the chromosphere. This increases both the intensity and suddenness of the
chromospheric heating, satisfying the basic conditions for an acoustic emission
that penetrates into the solar interior.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:53:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Martinez-Oliveros",
"J. C.",
""
],
[
"Moradi",
"H.",
""
],
[
"Besliu-Ionescu",
"D.",
""
],
[
"Donea",
"A. -C",
""
],
[
"Cally",
"P. S.",
""
],
[
"Lindsey",
"C.",
""
]
] |
0707.2020 | Tomohiro Ogawa | Fumio Hiai, Milan Mosonyi, Tomohiro Ogawa | Error exponents in hypothesis testing for correlated states on a spin
chain | 26 pages; discussions extended, 2 figures added | J. Math. Phys. 49 032112 (2008) | 10.1063/1.2872276 | null | quant-ph | null | We study various error exponents in a binary hypothesis testing problem and
extend recent results on the quantum Chernoff and Hoeffding bounds for product
states to a setting when both the null-hypothesis and the counter-hypothesis
can be correlated states on a spin chain. Our results apply to states
satisfying a certain factorization property; typical examples are the global
Gibbs states of translation-invariant finite-range interactions as well as
certain finitely correlated states.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:33:05 GMT"
},
{
"version": "v2",
"created": "Sat, 3 Nov 2007 09:02:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hiai",
"Fumio",
""
],
[
"Mosonyi",
"Milan",
""
],
[
"Ogawa",
"Tomohiro",
""
]
] |
0707.2021 | Kirill A. Kazakov | Guy Joulin, Hazem El-Rabii and Kirill A. Kazakov | On-Shell Description of Unsteady Flames | 21 pages, 3 figures; extended discussion of causality, new references
added | null | 10.1017/S0022112008002140 | null | physics.flu-dyn | null | The problem of non-perturbative description of unsteady premixed flames with
arbitrary gas expansion is solved in the two-dimensional case. Considering the
flame as a surface of discontinuity with arbitrary local burning rate and gas
velocity jumps given on it, we show that the front dynamics can be determined
without having to solve the flow equations in the bulk. On the basis of the
Thomson circulation theorem, an implicit integral representation of the gas
velocity downstream is constructed. It is then simplified by a successive
stripping of the potential contributions to obtain an explicit expression for
the vortex component near the flame front. We prove that the unknown potential
component is left bounded and divergence-free by this procedure, and hence can
be eliminated using the dispersion relation for its on-shell value (i.e., the
value along the flame front). The resulting system of integro-differential
equations relates the on-shell fuel velocity and the front position. As
limiting cases, these equations contain all theoretical results on flame
dynamics established so far, including the linear equation describing the
Darrieus-Landau instability of planar flames, and the nonlinear
Sivashinsky-Clavin equation for flames with weak gas expansion.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:41:00 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Jan 2008 20:50:52 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Joulin",
"Guy",
""
],
[
"El-Rabii",
"Hazem",
""
],
[
"Kazakov",
"Kirill A.",
""
]
] |
0707.2022 | Alexey Popov V | Alexey Popov (IHEP, Protvino on behalf of D0 collaboration) | W and Z Boson Production at sqrt(S)=1.96TeV with the D0 Detector | Proceedings of a poster session at Hadron Collider Physics Symposium
2006 (HCP 2006), Duke University, Durham, NC, May 22-26 2006; 3 pages, 3
figures | null | null | null | hep-ex | null | Preliminary measurements of the cross-section for the processes ppbar --> W
--> mu nu, e nu; ppbar --> Z --> mu mu, e e, tau tau from the D0 detector are
presented. Integrated luminosities for these data samples are 96 pb-1 for W -->
mu nu, 177.3 pb-1 for W --> e nu and Z --> e e, 148pb-1 for Z --> mu mu and 207
pb-1 for Z --> tau tau. A measurement of the muon charge asymmetry from W boson
decays (integrated luminosity 230 pb-1) and Z/gamma* --> e e inclusive
differential cross section as a function of boson rapidity (integrated
luminosity 337 pb-1) are presented as well. The results are in generally good
agreement with SM predictions.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 16:18:27 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Popov",
"Alexey",
"",
"IHEP, Protvino on behalf of D0 collaboration"
]
] |
0707.2023 | Yurii Lozovik | V.D. Mur, N.B. Narozhny, A.N. Petrosyan, Yu.E. Lozovik | Quantum Dot Version of Berry's Phase: Half-Integer Orbital Angular
Momenta | 4 pages, 2 figures | null | 10.1134/S0021364008220116 | null | cond-mat.mes-hall | null | We show that Berry's geometrical (topological) phase for circular quantum
dots with an odd number of electrons is equal to \pi and that eigenvalues of
the orbital angular momentum run over half-integer values. The non-zero value
of the Berry's phase is provided by axial symmetry and two-dimensionality of
the system. Its particular value (\pi) is fixed by the Pauli exclusion
principle. Our conclusions agree with the experimental results of T. Schmidt
{\it at el}, \PR B {\bf 51}, 5570 (1995), which can be considered as the first
experimental evidence for the existence of a new realization of Berry's phase
and half-integer values of the orbital angular momentum in a system of an odd
number of electrons in circular quantum dots.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:53:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mur",
"V. D.",
""
],
[
"Narozhny",
"N. B.",
""
],
[
"Petrosyan",
"A. N.",
""
],
[
"Lozovik",
"Yu. E.",
""
]
] |
0707.2024 | Tom Lancaster | T. Lancaster, S.J. Blundell, P.J. Baker, F.L. Pratt, W. Hayes, I.
Yamada, M. Azuma and M. Takano | A muon-spin relaxation study of BiMnO3 | 10 pages, 4 figures | J Phys Condens Matter 19, 376203 (2007) | 10.1088/0953-8984/19/37/376203 | null | cond-mat.str-el | null | We present the results of muon-spin relaxation measurements on ferromagnetic
BiMnO3. Below T_C=98.0(1) K oscillations in the time-dependence of the muon
polarization are observed, characteristic of a quasistatic magnetic field at a
single muon site, allowing us to probe the critical behaviour associated with
the magnetic phase transition. We are able to suggest candidate muon sites on
the basis of dipole field calculations. Close to T_C, fluctuations of the Mn^3+
moments are characteristic of critical behaviour while there is a sharp
crossover to a region of fast dynamic fluctuations at higher temperatures.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:53:26 GMT"
}
] | 2007-11-14T00:00:00 | [
[
"Lancaster",
"T.",
""
],
[
"Blundell",
"S. J.",
""
],
[
"Baker",
"P. J.",
""
],
[
"Pratt",
"F. L.",
""
],
[
"Hayes",
"W.",
""
],
[
"Yamada",
"I.",
""
],
[
"Azuma",
"M.",
""
],
[
"Takano",
"M.",
""
]
] |
0707.2025 | Genkai Zhang | M. Englis, K. Guo, G. Zhang | Toeplitz and Hankel operators and Dixmier traces on the unit ball of
\mathbb C^n | Proc. Amer. Math. Soc. to appear | null | null | null | math.CV math.FA | null | We compute the Dixmier trace of pseudo-Toeplitz operators on the Fock space.
As an application we find a formula for the Dixmier trace of the product of
commutators of Toeplitz operators on the Hardy and weighted Bergman spaces on
the unit ball of \mathbb C^d. This generalizes an earlier work of Helton-Howe
for the usual trace of the anti-symmetrization of Toeplitz operators.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 14:55:32 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Englis",
"M.",
""
],
[
"Guo",
"K.",
""
],
[
"Zhang",
"G.",
""
]
] |
0707.2026 | Dolors Herbera | Silvana Bazzoni and Dolors Herbera | Cotorsion pairs generated by modules of bounded projective dimension | 30 Pages | null | null | null | math.RA math.RT | null | We apply the theory of cotorsion pairs to study closure properties of classes
of modules with finite projective dimension with respect to direct limit
operations and to filtrations.
We also prove that if the ring is an order in an $\aleph_0$-noetherian ring Q
of small finitistic dimension 0, then the cotorsion pair generated by the
modules of projective dimension at most one is of finite type if and only if Q
has big finitistic dimension 0. This applies, for example, to semiprime Goldie
rings and Cohen Macaulay noetherian commutative rings.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 15:00:46 GMT"
},
{
"version": "v2",
"created": "Fri, 9 Nov 2007 16:55:47 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Bazzoni",
"Silvana",
""
],
[
"Herbera",
"Dolors",
""
]
] |
0707.2027 | Damien Chablat | Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN) | Workspace and Assembly modes in Fully-Parallel Manipulators : A
Descriptive Study | null | Advances in Robot Kinematics and Computational Geometry (1998)
117-126 | null | null | cs.RO | null | The goal of this paper is to explain, using a typical example, the
distribution of the different assembly modes in the workspace and their
effective role in the execution of trajectories. The singular and non-singular
changes of assembly mode are described and compared to each other. The
non-singular change of assembly mode is more deeply analysed and discussed in
the context of trajectory planning. In particular, it is shown that, according
to the location of the initial and final configurations with respect to the
uniqueness domains in the workspace, there are three different cases to
consider before planning a linking trajectory.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 15:04:13 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Wenger",
"Philippe",
"",
"IRCCyN"
],
[
"Chablat",
"Damien",
"",
"IRCCyN"
]
] |
0707.2028 | Keigo Fukumura | Keigo Fukumura, Demosthenes Kazanas | Mass Outflows from Dissipative Shocks in Hot Accretion Flows | 25 pages, 10 black&white figures, Accepted to ApJ | null | 10.1086/521578 | null | astro-ph | null | We consider stationary, axisymmetric hydrodynamic accretion flows in Kerr
geometry. As a plausible means of efficiently separating a small population of
nonthermal particles from the bulk accretion flows, we investigate the
formation of standing dissipative shocks, i.e. shocks at which fraction of the
energy, angular momentum and mass fluxes do not participate in the shock
transition of the flow that accretes onto the compact object but are lost into
collimated (jets) or uncollimated (winds) outflows. The mass loss fraction (at
a shock front) is found to vary over a wide range (0 - 95%) depending on flow's
angular momentum and energy. On the other hand, the associated energy loss
fraction appears to be relatively low (<1%) for a flow onto a non-rotating
black hole case, whereas the fraction could be an order of magnitude higher
(<10%) for a flow onto a rapidly-rotating black hole. By estimating the escape
velocity of the outflowing particles with a mass-accretion rate relevant for
typical active galactic nuclei, we find that nearly 10% of the accreting mass
could escape to form an outflow in a disk around a non-rotating black hole,
while as much as 50% of the matter may contribute to outflows in a disk around
a rapidly-rotating black hole. In the context of disk-jet paradigm, our model
suggests that shock-driven outflows from accretion can occur in regions not too
far from a central engine. Our results imply that a shock front under some
conditions could serve as a plausible site where (nonthermal) seed particles of
the outflows (jets/winds) are efficiently decoupled from bulk accretion.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 19:48:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fukumura",
"Keigo",
""
],
[
"Kazanas",
"Demosthenes",
""
]
] |
0707.2029 | Sebastian Stock | Sebastian Stock | Lifting SU(3)-structures to nearly parallel G_{2}-structures | 10 pages | null | null | null | math.DG math-ph math.MP | null | Hitchin shows that half-flat SU(3)-structures on a 6-dimensional manifold M
can be lifted to parallel G_{2}-structure on the product $M\times\mathbb{R}$.
We show that Hitchin's approach can also be used to construct nearly parallel
G_{2}-structures by lifting so-called nearly half-flat structures. These
SU(3)-structures are described by pairs $(\omega,\phi)$ of stable 2- and
3-forms with $d\phi=\lambda\omega^{2}$ for some
$\lambda\in\mathbb{R}\setminus\{0\}$.
| [
{
"version": "v1",
"created": "Fri, 13 Jul 2007 15:13:43 GMT"
}
] | 2007-07-16T00:00:00 | [
[
"Stock",
"Sebastian",
""
]
] |
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