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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0705.1598 | Simo S\"arkk\"a | Simo S\"arkk\"a and Tommi Sottinen | Application of Girsanov Theorem to Particle Filtering of Discretely
Observed Continuous-Time Non-Linear Systems | Paper in form as it has been accepted to Bayesian Analysis | null | null | null | stat.ME stat.CO | null | This article considers the application of particle filtering to
continuous-discrete optimal filtering problems, where the system model is a
stochastic differential equation, and noisy measurements of the system are
obtained at discrete instances of time. It is shown how the Girsanov theorem
can be used for evaluating the likelihood ratios needed in importance sampling.
It is also shown how the methodology can be applied to a class of models, where
the driving noise process is lower in the dimensionality than the state and
thus the laws of state and noise are not absolutely continuous.
Rao-Blackwellization of conditionally Gaussian models and unknown static
parameter models is also considered.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:02:38 GMT"
},
{
"version": "v2",
"created": "Tue, 29 Apr 2008 12:38:16 GMT"
}
] | 2008-04-29T00:00:00 | [
[
"Särkkä",
"Simo",
""
],
[
"Sottinen",
"Tommi",
""
]
] |
0705.1599 | Bruno Binggeli | Bruno Binggeli and Tatjana Hascher | Is There a Universal Mass Function? | 17 pages, 11 figures - Accepted for publication in PASP (review) | Publ.Astron.Soc.Pac.119:592,2007 | 10.1086/519533 | null | astro-ph | null | Following an old idea of Fritz Zwicky, we make an attempt to establish a
universal mass function for astronomical objects on all scales. The object
classes considered are: solar system planets and small bodies, exoplanets,
brown dwarfs, stars and stellar remnants, open and globular clusters, molecular
clouds, galaxies, groups and clusters of galaxies. For comparison we also
include CDM halos taken from numerical simulations. We show that the mass
functions of individual object classes, when properly normalized, can indeed be
concatenated to build a surprisingly continuous mass function of the universe,
from approximately M = 10^(-20)Msun (sub-kilometer size asteroids) up to M =
10^(16)Msun (rich clusters of galaxies), covering 36 orders of magnitude in
mass. Most individual mass functions roughly follow a power law of the form
phi(M) propto M^(-2). A notable exception are planets and small bodies which
seem to obey a flatter distribution. CDM halos from high-resolution numerical
simulations show a very similar relation, again of universal slope -2, from
clusters of galaxies all the way down to the planetary mass scale. On the scale
of stars and star clusters this is a remarkable coincidence, as the formation
processes involved are thought to be totally different (bottom-up gravitational
clustering of DM halos versus top-down gravoturbulent fragmentation of gas
clouds).
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:11:31 GMT"
}
] | 2009-11-16T00:00:00 | [
[
"Binggeli",
"Bruno",
""
],
[
"Hascher",
"Tatjana",
""
]
] |
0705.1600 | Anirban Pathak | Anirban Pathak | A mathematical criterion for single photon sources used in quantum
cryptography | 8 pages, no figure, Latex 2e | Indian J. Phys. Vol 80 (2006) page 495-499 | null | null | quant-ph | null | A single photon source (SPS) is very important for quantum computation. In
particular, it is essential for secured quantum cryptography. But there is no
perfect SPS in reality. Therefore, probabilistic SPS where probability of
simultaneous emission of two, three, four and more photon is less than the
emission of a single photon are used. Since classical photon always comes in
bunch, the required single photon source must be nonclassical. In the
well-known antibunched state the rate of simultaneous emission of two photon is
less than that of single photon. But the requirement of quantum cryptography is
a multiphoton version of the antibunched state or the higher order antibunched
state. Recently we have reported a mathematical criterion for higher order
antibunching. Here we have shown that any proposal for SPS to be used in
quantum cryptography should satisfy this criterion. We have studied four wave
mixing as a possible candidate of single photon source.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:12:07 GMT"
}
] | 2022-06-10T00:00:00 | [
[
"Pathak",
"Anirban",
""
]
] |
0705.1601 | Ben Reichardt | Ben W. Reichardt | Proof of the Double Bubble Conjecture in R^n | 20 pages, 22 figures | J. Geom. Anal. 18(1):172-191, 2008 | 10.1007/s12220-007-9002-y | null | math.MG | null | The least-area hypersurface enclosing and separating two given volumes in R^n
is the standard double bubble.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:15:52 GMT"
}
] | 2009-06-19T00:00:00 | [
[
"Reichardt",
"Ben W.",
""
]
] |
0705.1602 | Tatyana I. Baturina | T.I. Baturina, A.Yu. Mironov, V.M. Vinokur, M.R. Baklanov, C. Strunk | Localized Superconductivity in the Quantum-Critical Region of the
Disorder-Driven Superconductor-Insulator Transition in TiN Thin Films | 4 pages, 4 figures, published version | Physical Review Letters 99, 257003 (2007) | 10.1103/PhysRevLett.99.257003 | null | cond-mat.supr-con cond-mat.dis-nn | null | We investigate low-temperature transport properties of thin TiN
superconducting films in the vicinity of the disorder-driven
superconductor-insulator transition. In a zero magnetic field, we find an
extremely sharp separation between superconducting and insulating phases,
evidencing a direct superconductor-insulator transition without an intermediate
metallic phase. At moderate temperatures, in the insulating films we reveal
thermally activated conductivity with the magnetic field-dependent activation
energy. At very low temperatures, we observe a zero-conductivity state, which
is destroyed at some depinning threshold voltage V_T. These findings indicate
formation of a distinct collective state of the localized Cooper pairs in the
critical region at both sides of the transition.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:29:04 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Jan 2008 18:28:57 GMT"
}
] | 2008-01-02T00:00:00 | [
[
"Baturina",
"T. I.",
""
],
[
"Mironov",
"A. Yu.",
""
],
[
"Vinokur",
"V. M.",
""
],
[
"Baklanov",
"M. R.",
""
],
[
"Strunk",
"C.",
""
]
] |
0705.1603 | Andreas Wirzba | Ulf-G. Mei{\ss}ner, A.M. Rakhimov, A. Wirzba and U.T. Yakhshiev | Neutron-proton mass difference in isospin asymmetric nuclear matter | 11 pages, 6 figures; some new references added | Eur.Phys.J.A32:299-309,2007 | 10.1140/epja/i2007-10390-9 | FZJ-IKP-TH-2007-17 | nucl-th | null | Isospin-breaking effects in the baryonic sector are studied in the framework
of a medium-modified Skyrme model. The neutron-proton mass difference in
infinite, asymmetric nuclear matter is discussed. In order to describe the
influence of the nuclear environment on the skyrmions, we include
energy-dependent charged and neutral pion optical potentials in the s- and
p-wave channels. The present approach predicts that the neutron-proton mass
difference is mainly dictated by its strong part and that it strongly decreases
in neutron matter.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:46:45 GMT"
},
{
"version": "v2",
"created": "Thu, 24 May 2007 12:30:26 GMT"
}
] | 2009-06-09T00:00:00 | [
[
"Meißner",
"Ulf-G.",
""
],
[
"Rakhimov",
"A. M.",
""
],
[
"Wirzba",
"A.",
""
],
[
"Yakhshiev",
"U. T.",
""
]
] |
0705.1604 | Jun-Yi Zhang | J.-Y. Zhang, Z.-C. Yan, D. Vrinceanu, J. F. Babb, and H. R. Sadeghpour | Accurate long-range coefficients for two excited like isotope He atoms:
He($2 ^1P$)--He($2 ^1P$), He($2 ^1P$)--He($2 ^3P$), and He($2 ^3P$)--He($2
^3P$) | null | Phys. Rev. A 76, 012723 (2007) | 10.1103/PhysRevA.76.012723 | null | physics.atom-ph physics.comp-ph | null | A general formalism is used to express the long-range potential energies in
inverse powers of the separation distance between two like atomic or molecular
systems with $P$ symmetries. The long-range molecular interaction coefficients
are calculated for the molecular symmetries $\Delta$, $\Pi$, and $\Sigma$,
arising from the following interactions: He($2 ^1P$)--He($2 ^1P$), He($2
^1P$)--He($2 ^3P$), and He($2 ^3P$)--He($2 ^3P$). The electric
quadrupole-quadrupole term, $C_{5}$, the van der Waals (dispersion) term
$C_{6}$, and higher-order terms, $C_{8}$, and $C_{10}$, are calculated
\textit{ab initio} using accurate variational wave functions in Hylleraas
coordinates with finite nuclear mass effects. A comparison is made with
previously published results where available.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:53:10 GMT"
}
] | 2007-08-01T00:00:00 | [
[
"Zhang",
"J. -Y.",
""
],
[
"Yan",
"Z. -C.",
""
],
[
"Vrinceanu",
"D.",
""
],
[
"Babb",
"J. F.",
""
],
[
"Sadeghpour",
"H. R.",
""
]
] |
0705.1605 | Svenja Carrigan | H.E.S.S. Collaboration: F. Aharonian, et al | Discovery of two candidate pulsar wind nebulae in very-high-energy gamma
rays | 10 pages, 3 figures, 2 tables, to appear in A&A | A&A 472, 489-495 (2007) | 10.1051/0004-6361:20077280 | null | astro-ph | null | We present the discovery of two very-high-energy gamma-ray sources in an
ongoing systematic search for emission above 100 GeV from pulsar wind nebulae
in survey data from the H.E.S.S. telescope array. Imaging Atmospheric Cherenkov
Telescopes are ideal tools for searching for extended emission from pulsar wind
nebulae in the very-high-energy regime. H.E.S.S., with its large field of view
of 5 degrees and high sensitivity, gives new prospects for the search for these
objects. An ongoing systematic search for very-high-energy emission from
energetic pulsars over the region of the Galactic plane between -60 degrees < l
< 30 degrees, -2 degrees < b < 2 degrees is performed. For the resulting
candidates, the standard H.E.S.S. analysis was applied and a search for
multi-wavelength counterparts was performed. We present the discovery of two
new candidate gamma-ray pulsar wind nebulae, HESS J1718-385 and HESS J1809-193.
H.E.S.S. has proven to be a suitable instrument for pulsar wind nebula
searches.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 08:58:59 GMT"
}
] | 2012-08-27T00:00:00 | [
[
"Collaboration",
"H. E. S. S.",
""
],
[
":",
"",
""
],
[
"Aharonian",
"F.",
""
]
] |
0705.1606 | Dennis C. Rapaport | D. C. Rapaport | Microscale swimming: The molecular dynamics approach | 5 pages, 3 figures (minor changes to text) | Phys. Rev.Lett. 99 (2007) 238101 | 10.1103/PhysRevLett.99.238101 | null | cond-mat.soft q-bio.SC | null | The self-propelled motion of microscopic bodies immersed in a fluid medium is
studied using molecular dynamics simulation. The advantage of the atomistic
approach is that the detailed level of description allows complete freedom in
specifying the swimmer design and its coupling with the surrounding fluid. A
series of two-dimensional swimming bodies employing a variety of propulsion
mechanisms -- motivated by biological and microrobotic designs -- is
investigated, including the use of moving limbs, changing body shapes and fluid
jets. The swimming efficiency and the nature of the induced, time-dependent
flow fields are found to differ widely among body designs and propulsion
mechanisms.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:02:35 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Dec 2007 12:29:54 GMT"
}
] | 2007-12-06T00:00:00 | [
[
"Rapaport",
"D. C.",
""
]
] |
0705.1607 | Kentaro Nomura | Kentaro Nomura, Mikito Koshino, Shinsei Ryu | Topological delocalization of two-dimensional massless Dirac fermions | 4 pages, 2 figures | Phys. Rev. Lett. 99, 146806 (2007) | 10.1103/PhysRevLett.99.146806 | null | cond-mat.mes-hall | null | The beta function of a two-dimensional massless Dirac Hamiltonian subject to
a random scalar potential, which e.g., underlies the theoretical description of
graphene, is computed numerically. Although it belongs to, from a symmetry
standpoint, the two-dimensional symplectic class, the beta function
monotonically increases with decreasing $g$. We also provide an argument based
on the spectral flows under twisting boundary conditions, which shows that none
of states of the massless Dirac Hamiltonian can be localized.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:09:41 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 06:06:16 GMT"
}
] | 2008-06-30T00:00:00 | [
[
"Nomura",
"Kentaro",
""
],
[
"Koshino",
"Mikito",
""
],
[
"Ryu",
"Shinsei",
""
]
] |
0705.1608 | Oliver Muelken | Oliver Muelken, Volker Pernice, Alexander Blumen | Quantum transport on small-world networks: A continuous-time quantum
walk approach | 8 pages, 8 figures (high quality figures available upon request) | Phys. Rev. E 76, 051125 (2007) | 10.1103/PhysRevE.76.051125 | null | quant-ph cond-mat.stat-mech | null | We consider the quantum mechanical transport of (coherent) excitons on
small-world networks (SWN). The SWN are build from a one-dimensional ring of N
nodes by randomly introducing B additional bonds between them. The exciton
dynamics is modeled by continuous-time quantum walks and we evaluate
numerically the ensemble averaged transition probability to reach any node of
the network from the initially excited one. For sufficiently large B we find
that the quantum mechanical transport through the SWN is, first, very fast,
given that the limiting value of the transition probability is reached very
quickly; second, that the transport does not lead to equipartition, given that
on average the exciton is most likely to be found at the initial node.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:19:29 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 07:52:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Muelken",
"Oliver",
""
],
[
"Pernice",
"Volker",
""
],
[
"Blumen",
"Alexander",
""
]
] |
0705.1609 | Lubomir Gavrilov | Sebastien Gautier, Lubomir Gavrilov, Iliya D. Iliev | Perturbations of quadratic centers of genus one | 28 pages | Discrete Contin. Dyn. Syst. 25 (2009), no. 2, 511-535 | null | null | math.DS math.CA | null | We propose a program for finding the cyclicity of period annuli of quadratic
systems with centers of genus one. As a first step, we classify all such
systems and determine the essential one-parameter quadratic perturbations which
produce the maximal number of limit cycles. We compute the associated
Poincare-Pontryagin-Melnikov functions whose zeros control the number of limit
cycles. To illustrate our approach, we determine the cyclicity of the annuli of
two particular reversible systems.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:30:23 GMT"
},
{
"version": "v2",
"created": "Sat, 24 Nov 2007 16:59:34 GMT"
}
] | 2011-03-30T00:00:00 | [
[
"Gautier",
"Sebastien",
""
],
[
"Gavrilov",
"Lubomir",
""
],
[
"Iliev",
"Iliya D.",
""
]
] |
0705.1610 | Feliks Przytycki | W. Marzantowicz, F. Przytycki | Estimates of the topological entropy from below for continuous self-maps
on some compact manifolds | 13 pages | null | null | null | math.DS math.AT | null | Extending our results in "Entropy conjecture for continuous maps of
nilmanifolds", to appear in Israel Jour. of Math., we confirm that Entropy
Conjecture holds for every continuous self-map of a compact $K(\pi,1)$ manifold
with the fundamental group $\pi$ torsion free and virtually nilpotent, in
particular for every continuous map of an infra-nilmanifold. In fact we prove a
stronger version, a lower estimate of the topological entropy of a map by
logarithm of the spectral radius of an associated "linearization matrix" with
integer entries.
From this, referring to known estimates of Mahler measure of polynomials, we
deduce some absolute lower bounds for the entropy.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:42:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marzantowicz",
"W.",
""
],
[
"Przytycki",
"F.",
""
]
] |
0705.1611 | Shi-Jian Gu | Z. G. Wang, Y. G. Chen, S. J. Gu | Bosonization study of quantum phase transitions in the one-dimensional
asymmetric Hubbard model | 6 pages, 3 figures | Z. G. Wang, Y. G. Chen, and S. J. Gu, Phys. Rev. B 75, 165111
(2007) | 10.1103/PhysRevB.75.165111 | null | cond-mat.str-el | null | The quantum phase transitions in the one-dimensional asymmetric Hubbard model
are investigated with the bosonization approach. The conditions for the phase
transition from density wave to phase separation, the correlation functions and
their exponents are obtained analytically. Our results show that the difference
between the hopping integrals for up- and down-spin electrons is crucial for
the happening of the phase separation. When the difference is large enough, the
phase separation will appear even if the on-site interaction is small.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:54:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"Z. G.",
""
],
[
"Chen",
"Y. G.",
""
],
[
"Gu",
"S. J.",
""
]
] |
0705.1612 | Enrico Paolini | E. Paolini, M. Chiani | A Class of LDPC Erasure Distributions with Closed-Form Threshold
Expression | 6 pages. To appear in Proceedings of ICC 2007 | null | null | null | cs.IT math.IT | null | In this paper, a family of low-density parity-check (LDPC) degree
distributions, whose decoding threshold on the binary erasure channel (BEC)
admits a simple closed form, is presented. These degree distributions are a
subset of the check regular distributions (i.e. all the check nodes have the
same degree), and are referred to as $p$-positive distributions. It is given
proof that the threshold for a $p$-positive distribution is simply expressed by
$[\lambda'(0)\rho'(1)]^{-1}$. Besides this closed form threshold expression,
the $p$-positive distributions exhibit three additional properties. First, for
given code rate, check degree and maximum variable degree, they are in some
cases characterized by a threshold which is extremely close to that of the best
known check regular distributions, under the same set of constraints. Second,
the threshold optimization problem within the $p$-positive class can be solved
in some cases with analytic methods, without using any numerical optimization
tool. Third, these distributions can achieve the BEC capacity. The last
property is shown by proving that the well-known binomial degree distributions
belong to the $p$-positive family.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:11:47 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Paolini",
"E.",
""
],
[
"Chiani",
"M.",
""
]
] |
0705.1613 | Dhafer Malouche DM | Dhafer Malouche | Determining full conditional independence by low-order conditioning | Published in at http://dx.doi.org/10.3150/09-BEJ193 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm) | Bernoulli 2009, Vol. 15, No. 4, 1179-1189 | 10.3150/09-BEJ193 | IMS-BEJ-BEJ193 | math.ST stat.ML stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A concentration graph associated with a random vector is an undirected graph
where each vertex corresponds to one random variable in the vector. The absence
of an edge between any pair of vertices (or variables) is equivalent to full
conditional independence between these two variables given all the other
variables. In the multivariate Gaussian case, the absence of an edge
corresponds to a zero coefficient in the precision matrix, which is the inverse
of the covariance matrix. It is well known that this concentration graph
represents some of the conditional independencies in the distribution of the
associated random vector. These conditional independencies correspond to the
"separations" or absence of edges in that graph. In this paper we assume that
there are no other independencies present in the probability distribution than
those represented by the graph. This property is called the perfect
Markovianity of the probability distribution with respect to the associated
concentration graph. We prove in this paper that this particular concentration
graph, the one associated with a perfect Markov distribution, can be determined
by only conditioning on a limited number of variables. We demonstrate that this
number is equal to the maximum size of the minimal separators in the
concentration graph.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 09:59:53 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Feb 2009 14:24:07 GMT"
},
{
"version": "v3",
"created": "Sun, 20 Dec 2009 07:00:47 GMT"
},
{
"version": "v4",
"created": "Thu, 14 Jan 2010 07:45:38 GMT"
}
] | 2010-01-14T00:00:00 | [
[
"Malouche",
"Dhafer",
""
]
] |
0705.1614 | Qingyang Guan | Qingyang Guan | Boundary Harnack inequalities for regional fractional Laplacian | 27 pages, some corrections and adding the Lipschitz case | null | null | null | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider boundary Harnack inequalities for regional fractional Laplacian
which are generators of censored stable-like processes on G taking
\kappa(x,y)/|x-y|^{n+\alpha}dxdy, x,y\in G as the jumping measure. When G is a
C^{1,\beta-1} open set, 1<\alpha<\beta\leq 2 and \kappa\in
C^{1}(\overline{G}\times \overline{G}) bounded between two positive numbers, we
prove a boundary Harnack inequality giving dist(x,\partial G)^{\alpha-1} order
decay for harmonic functions near the boundary. For a C^{1,\beta-1} open set
D\subset \overline{D}\subset G, 0<\alpha\leq (1\vee\alpha)<\beta\leq 2, we
prove a boundary Harnack inequality giving dist(x,\partial D)^{\alpha/2} order
decay for harmonic functions near the boundary. These inequalities are
generalizations of the known results for the homogeneous case on C^{1,1} open
sets. We also prove the boundary Harnack inequality for regional fractional
Laplacian on Lipschitz domain.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:42:28 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Sep 2008 16:52:26 GMT"
},
{
"version": "v3",
"created": "Fri, 17 Jul 2009 09:19:33 GMT"
}
] | 2009-07-17T00:00:00 | [
[
"Guan",
"Qingyang",
""
]
] |
0705.1615 | De Troia Grazia | G. De Troia, P.A.R. Ade, J.J. Bock, J.R. Bond, J. Borrill, A.
Boscaleri, P. Cabella, C.R. Contaldi, B.P. Crill, P. de Bernardis, G. De
Gasperis, A. de Oliveira-Costa, G. Di Stefano, P. G. Ferreira, E. Hivon, A.H.
Jaffe, T.S.Kisner, M. Kunz, W.C. Jones, A.E. Lange, M.Liguori, S. Masi, S.
Matarrese, P.D. Mauskopf, C.J. MacTavish, A. Melchiorri, T.E. Montroy, P.
Natoli, C.B. Netterfield, E. Pascale, F. Piacentini, D. Pogosyan, G.Polenta,
S. Prunet, S. Ricciardi, G. Romeo, J.E. Ruhl, P. Santini, M. Tegmark, M.
Veneziani, and N. Vittorio | Searching for non Gaussian signals in the BOOMERanG 2003 CMB maps | accepted for publication in ApJ. Letters | Astrophys.J.670:L36,2007 | 10.1016/j.newar.2006.11.064 | null | astro-ph | null | We analyze the BOOMERanG 2003 (B03) 145 GHz temperature map to constrain the
amplitude of a non Gaussian, primordial contribution to CMB fluctuations. We
perform a pixel space analysis restricted to a portion of the map chosen in
view of high sensitivity, very low foreground contamination and tight control
of systematic effects. We set up an estimator based on the three Minkowski
functionals which relies on high quality simulated data, including non Gaussian
CMB maps. We find good agreement with the Gaussian hypothesis and derive the
first limits based on BOOMERanG data for the non linear coupling parameter f_NL
as -300<f_NL<650 at 68% CL and -800<f_NL<1050 at 95% CL.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:18:51 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 07:20:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"De Troia",
"G.",
""
],
[
"Ade",
"P. A. R.",
""
],
[
"Bock",
"J. J.",
""
],
[
"Bond",
"J. R.",
""
],
[
"Borrill",
"J.",
""
],
[
"Boscaleri",
"A.",
""
],
[
"Cabella",
"P.",
""
],
[
"Contaldi",
"C. R.",
""
],
[
"Crill",
"B. P.",
""
],
[
"de Bernardis",
"P.",
""
],
[
"De Gasperis",
"G.",
""
],
[
"de Oliveira-Costa",
"A.",
""
],
[
"Di Stefano",
"G.",
""
],
[
"Ferreira",
"P. G.",
""
],
[
"Hivon",
"E.",
""
],
[
"Jaffe",
"A. H.",
""
],
[
"Kisner",
"T. S.",
""
],
[
"Kunz",
"M.",
""
],
[
"Jones",
"W. C.",
""
],
[
"Lange",
"A. E.",
""
],
[
"Liguori",
"M.",
""
],
[
"Masi",
"S.",
""
],
[
"Matarrese",
"S.",
""
],
[
"Mauskopf",
"P. D.",
""
],
[
"MacTavish",
"C. J.",
""
],
[
"Melchiorri",
"A.",
""
],
[
"Montroy",
"T. E.",
""
],
[
"Natoli",
"P.",
""
],
[
"Netterfield",
"C. B.",
""
],
[
"Pascale",
"E.",
""
],
[
"Piacentini",
"F.",
""
],
[
"Pogosyan",
"D.",
""
],
[
"Polenta",
"G.",
""
],
[
"Prunet",
"S.",
""
],
[
"Ricciardi",
"S.",
""
],
[
"Romeo",
"G.",
""
],
[
"Ruhl",
"J. E.",
""
],
[
"Santini",
"P.",
""
],
[
"Tegmark",
"M.",
""
],
[
"Veneziani",
"M.",
""
],
[
"Vittorio",
"N.",
""
]
] |
0705.1616 | Dr. Georgios M. Nikolopoulos | C. Lazarou, G. M. Nikolopoulos, P. Lambropoulos | Non-Markovian dynamics in atom-laser outcoupling from a double-well
Bose-Einstein condensate | 21 pages, 9 figure, to appear in J. Phys. B | J. Phys. B: At. Mol. Opt. Phys. 40, 2511 (2007) | 10.1088/0953-4075/40/12/024 | null | quant-ph cond-mat.other | null | We investigate the dynamics of a continuous atom laser based on the merging
of independently formed atomic condensates. In a first attempt to understand
the dynamics of the system, we consider two independent elongated Bose-Einstein
condensates which approach each other and focus on intermediate inter-trap
distances so that a two-mode model is well justified. In the framework of a
mean-field theory, we discuss the quasi steady-state population of the traps as
well as the energy distribution of the outcoupled atoms.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:14:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lazarou",
"C.",
""
],
[
"Nikolopoulos",
"G. M.",
""
],
[
"Lambropoulos",
"P.",
""
]
] |
0705.1617 | Daegene Song | Daegene Song | Non-Computability of Consciousness | 10 pages, 2 figures, 1 table | NeuroQuantology 5, 382 (2007). | null | null | quant-ph astro-ph cs.AI | null | With the great success in simulating many intelligent behaviors using
computing devices, there has been an ongoing debate whether all conscious
activities are computational processes. In this paper, the answer to this
question is shown to be no. A certain phenomenon of consciousness is
demonstrated to be fully represented as a computational process using a quantum
computer. Based on the computability criterion discussed with Turing machines,
the model constructed is shown to necessarily involve a non-computable element.
The concept that this is solely a quantum effect and does not work for a
classical case is also discussed.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:16:48 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Song",
"Daegene",
""
]
] |
0705.1618 | Vivek Jain Kumar | V.K. Jain, R.P. Shukla | Finite Just Non-Dedekind Groups | 12 pages | International Journal of Algebra Vol 3, 2009, no 8, 391-400 | null | null | math.GR | null | A group is just non-Dedekind (JND) if it is not a Dedekind group but all of
whose proper homomorphic images are Dedekind groups. The aim of the paper is to
classify finite JND-groups.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:41:37 GMT"
}
] | 2019-05-21T00:00:00 | [
[
"Jain",
"V. K.",
""
],
[
"Shukla",
"R. P.",
""
]
] |
0705.1619 | Thierry Jolicoeur | Thierry Jolicoeur | Non-Abelian states with negative flux: a new series of quantum Hall
states | 4 pages, 5 figures | Phys. Rev. Lett. 99, 036805 (2007) | 10.1103/PhysRevLett.99.036805 | null | cond-mat.mes-hall | null | By applying the idea of parafermionic clustering to composite bosons with
positive as well as negative flux, a new series of trial wavefunctions to
describe fractional quantum Hall states is proposed. These non-Abelian states
compete at filling factors k/(3k +/- 2) with other ground states like stripes
or composite fermion states. These two series contain all the states recently
discovered by Pan et al. [Phys. Rev. Lett. 90, 016801 (2003)] including the
even denominator cases. Exact diagonalization studies on the sphere and torus
point to their possible relevance for filling factors 3/7, 3/11, and 3/8.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:42:56 GMT"
}
] | 2010-03-18T00:00:00 | [
[
"Jolicoeur",
"Thierry",
""
]
] |
0705.1620 | Gerrit Coddens | G. Coddens | Comment on "Structure factors of harmonic and anharmonic Fibonacci
chains by molecular dynamics simulations" | 2 pages, 0 Figures | null | null | null | cond-mat.dis-nn | null | Recently, Engel et al. discussed phonon broadening as observed in 3D
quasicrystals on the basis of calculations on the Fibonacci chain. We show that
the paper contains several statements and assumptions that are contradicted by
factual truth.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:59:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Coddens",
"G.",
""
]
] |
0705.1621 | Osmi Vilhu | Osmi Vilhu, Ada Paizis, Diana Hannikainen, Juho Schultz and Volker
Beckmann | The Spreading Layer of GX 9+9 | 4 pages (pdf), proceedings of the 6th INTEGRAL Workshop 'The Obscured
Universe', July 2-8 2006, ESA SP-622 | null | null | null | astro-ph | null | The spreading layer (SL) on neutron star surface of GX 9+9 during the upper
banana state was studied using INTEGRAL and RXTE observations. The SL-area
becomes larger with increasing accretion rate while the SL-temperature remains
close to the critical Eddington value, confirming predictions by Inogamov and
Sunyaev (1999) and Suleimanov and Poutanen (2006). However, at low accretion
rate the observed temperature is higher and SL-belt shallower than those
predicted, requiring confirmation and theoretical explananation.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 10:55:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vilhu",
"Osmi",
""
],
[
"Paizis",
"Ada",
""
],
[
"Hannikainen",
"Diana",
""
],
[
"Schultz",
"Juho",
""
],
[
"Beckmann",
"Volker",
""
]
] |
0705.1622 | Daniel Vogt | Daniel Vogt and Patricio S. Letelier | Triaxial Analytical Potential-Density Pairs for Galaxies | 9 pages, 4 figures, accepted for publication in PASJ | Publ.Astron.Soc.Jap.59:319,2007 | 10.1093/pasj/59.2.319 | null | astro-ph | null | We present two triaxial analytical potential-density pairs that can be viewed
as generalized versions of the axisymmetric Miyamoto and Nagai and Satoh
galactic models. These potential-density pairs may be useful models for
galaxies with box-shaped bulges. The resulting mass density distributions are
everywhere non-negative and free from singularities. Also, a few numerically
calculated orbits for the Miyamoto and Nagai-like triaxial potential are
presented.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:06:14 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Vogt",
"Daniel",
""
],
[
"Letelier",
"Patricio S.",
""
]
] |
0705.1623 | Sharon Cooper Dr | Sharon Cooper, Catherine Nicholson, Jian Liu | A simple model for predicting crystallization and melting temperatures,
and its implications for phase transitions in confined volumes | 26 pages, 8 figures, 1 table | null | 10.1063/1.2977993 | null | cond-mat.mtrl-sci | null | We present a simple unifying model for crystallization and melting
temperatures by showing that homogeneous nucleation and phase transformations
driven by thickening of pre-existing surface layers are limiting conditions of
the more general heterogeneous nucleation case. Furthermore, to a first
approximation all these processes can be described by an extended classical
nucleation theory. The model can also be applied to phase transition
temperatures in confined volumes, provided reliable values for the interfacial
tensions within the systems are determinable. The expected melting and
crystallization temperature for any transformation pathway can then be
predicted.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:11:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cooper",
"Sharon",
""
],
[
"Nicholson",
"Catherine",
""
],
[
"Liu",
"Jian",
""
]
] |
0705.1624 | Luca Silvestrini | Luca Silvestrini | Searching for New Physics in b to s Hadronic Penguin Decays | 44 pages, 13 figures, invited review to appear in Ann. Rev. of Nucl.
and Part. Science | Ann.Rev.Nucl.Part.Sci.57:405-440,2007 | 10.1146/annurev.nucl.57.090506.123007 | null | hep-ph | null | We review the theoretical status of b to s hadronic penguin decays in the
Standard Model and beyond. We summarize the main theoretical tools to compute
Branching Ratios and CP asymmetries for b to s penguin dominated nonleptonic
decays, and discuss the theoretical uncertainties in the prediction of
time-dependent CP asymmetries in this processes. We consider general aspects of
b to s transitions beyond the Standard Model. Then we present detailed
predictions in supersymmetric models with new sources of flavor and CP
violation.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:16:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Silvestrini",
"Luca",
""
]
] |
0705.1625 | G\"ulay Dereli | G. Dereli, B. Sungu, C. Ozdogan | Thermal Stability of Metallic Single-Walled Carbon Nanotubes: An O(N)
Tight-Binding Molecular Dynamics Simulation Study | null | null | 10.1088/0957-4484/18/24/245704 | null | cond-mat.mtrl-sci cond-mat.other | null | Order(N) Tight-Binding Molecular Dynamics (TBMD) simulations are performed to
investigate the thermal stability of (10,10) metallic Single-Walled Carbon
Nanotubes (SWCNT). Periodic boundary conditions (PBC) are applied in axial
direction. Velocity Verlet algorithm along with the canonical ensemble
molecular dynamics (NVT) is used to simulate the tubes at the targeted
temperatures. The effects of slow and rapid temperature increases on the
physical characteristics, structural stability and the energetics of the tube
are investigated and compared. Simulations are carried out starting from room
temperature and the temperature is raised in steps of 300K. Stability of the
simulated metallic SWCNT is examined at each step before it is heated to higher
temperatures. First indication of structural deformation is observed at 600K.
For higher heat treatments the deformations are more pronounced and the bond
breaking temperature is reached around 2500K. Gradual (slow) heating and
thermal equilibrium (fast heating) methods give the value of radial thermal
expansion coefficient in the temperature range between 300K-600K as
0.31x10^{-5}(1/K) and 0.089x10^{-5}(1/K), respectively. After 600K, both
methods give the same value of 0.089x10^{-5}(1/K). The ratio of the total
energy per atom with respect to temperature is found to be 3x10^{-4} eV/K.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:16:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dereli",
"G.",
""
],
[
"Sungu",
"B.",
""
],
[
"Ozdogan",
"C.",
""
]
] |
0705.1626 | Lung-Yih Chiang | Lung-Yih Chiang (1,2) and Pavel D. Naselsky (2,3) ((1)ASIAA, Taiwan,
(2)NBI, Denmark, (3)Southern Federal University, Russia) | Phase analysis of the cosmic microwave background from an incomplete sky
coverage | 5 pages, 3 figures submitted to MNRAS Letters, replaced with minor
changes | Mon.Not.Roy.Astron.Soc.380:L71,2007 | 10.1111/j.1745-3933.2007.00352.x | null | astro-ph | null | Phases of the spherical harmonic analysis of full-sky cosmic microwave
background (CMB) temperature data contain useful information complementary to
the ubiquitous angular power spectrum. In this letter we present a new method
of phase analysis on incomplete sky maps. It is based on Fourier phases of
equal-latitude pixel rings of the map, which are related to the mean angle of
the trigonometric moments from the full-sky phases. They have an advantage for
probing regions of interest without tapping polluted Galactic plane area, and
can localize non-Gaussian features and departure from statistical isotropy in
the CMB.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:30:00 GMT"
},
{
"version": "v2",
"created": "Mon, 14 May 2007 06:49:20 GMT"
},
{
"version": "v3",
"created": "Thu, 14 Jun 2007 03:49:26 GMT"
}
] | 2009-11-16T00:00:00 | [
[
"Chiang",
"Lung-Yih",
""
],
[
"Naselsky",
"Pavel D.",
""
]
] |
0705.1627 | Xiaobing Luo | Xiaobing Luo, Qiongtao Xie, Biao Wu | Nonlinear coherent destruction of tunneling | 4 pages,5 figures | PhysRevA, 76, 051802(R)(2007) | 10.1103/PhysRevA.76.051802 | null | quant-ph | null | We study theoretically two coupled periodically-curved optical waveguides
with Kerr nonlinearity. We find that the tunneling between the waveguides can
be suppressed in a wide range of parameters due to nonlinearity. Such
suppression of tunneling is different from the coherent destruction of
tunneling in a linear medium, which occurs only at the isolated degeneracy
point of the quasienergies. We call this novel suppression nonlinear coherent
destruction of tunneling.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:34:31 GMT"
}
] | 2013-05-07T00:00:00 | [
[
"Luo",
"Xiaobing",
""
],
[
"Xie",
"Qiongtao",
""
],
[
"Wu",
"Biao",
""
]
] |
0705.1628 | Zaza Osmanov | N. Chkheidze, G. Machabeli | The Plasma Emission Model of RX J1856.5-3754 | 5 pages, 4 figures | null | 10.1051/0004-6361:20077152 | null | astro-ph | null | A spectral analysis of the nearby isolated neutron star RX J1856.5-3754 is
presented. Applying the kinetic approach, the distribution functions of
emitting electrons are derived and the entire spectra is fitted. It is found
that waves excited by the cyclotron mechanism, come in the radio domain. We
confirm that the cyclotron instability is quite efficient, since the
estimations show that the time of wave-particle interaction is long enough for
particles to acquire perpendicular momentum and generate observed radiation.
The lack of rotational modulation is discussed and the pulsar spin period is
estimated.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:50:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chkheidze",
"N.",
""
],
[
"Machabeli",
"G.",
""
]
] |
0705.1629 | Valentin Ovsienko | Valentin Ovsienko (ICJ) | Lie antialgebras: premices | This is the final version | null | null | null | math-ph math.MP math.QA math.SG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The main purpose of this work is to develop the basic notions of the Lie
theory for commutative algebras. We introduce a class of $\mathbbZ_2$-graded
commutative but not associative algebras that we call ``Lie antialgebras''.
These algebras are closely related to Lie (super)algebras and, in some sense,
link together commutative and Lie algebras. The main notions we define in this
paper are: representations of Lie antialgebras, an analog of the Lie-Poisson
bivector (which is not Poisson) and central extensions. We also classify simple
finite-dimensional Lie antialgebras.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:59:18 GMT"
},
{
"version": "v2",
"created": "Tue, 15 May 2007 12:04:22 GMT"
},
{
"version": "v3",
"created": "Mon, 13 Aug 2007 19:09:04 GMT"
},
{
"version": "v4",
"created": "Fri, 5 Oct 2007 15:24:20 GMT"
},
{
"version": "v5",
"created": "Tue, 24 Mar 2009 07:15:03 GMT"
},
{
"version": "v6",
"created": "Fri, 15 Oct 2010 04:26:41 GMT"
}
] | 2010-10-18T00:00:00 | [
[
"Ovsienko",
"Valentin",
"",
"ICJ"
]
] |
0705.1630 | Marc Wouts | Marc Wouts (PMA) | A coarse graining for the Fortuin-Kasteleyn measure in random media | 55 pages, 6 figures | Stochastic Processes and their Applications 118, 11 (2008)
1929-1972 | 10.1016/j.spa.2007.11.009 | null | math-ph math.MP math.PR | null | By means of a multi-scale analysis we describe the typical geometrical
structure of the clusters under the FK measure in random media. Our result
holds in any dimension greater or equal to 2 provided that slab percolation
occurs under the averaged measure, which should be the case in the whole
supercritical phase. This work extends the one of Pisztora and provides an
essential tool for the analysis of the supercritical regime in disordered FK
models and in the corresponding disordered Ising and Potts models.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:00:12 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Dec 2007 19:47:19 GMT"
}
] | 2008-11-07T00:00:00 | [
[
"Wouts",
"Marc",
"",
"PMA"
]
] |
0705.1631 | Maxime Clusel | Maxime Clusel (ILL), Timothy Ziman (ILL, PMMC) | Transverse magnetization and transient oscillations in the quantum
tunneling of molecular magnets | null | null | null | null | cond-mat.stat-mech quant-ph | null | We calculate the response of a molecular magnet subject to a time-varying
magnetic field and coupled to a heat bath. We propose that observations of
calculated oscillations transverse to the field direction may be an effective
way of demonstrating quantum tunneling and thus probing the details of level
repulsion. The effective model of a triangle of Heisenberg spins and weak
anisotropies, as has been used to model the molecular magnets V15 and Cu3, is
used to illustrate this.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:01:06 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Clusel",
"Maxime",
"",
"ILL"
],
[
"Ziman",
"Timothy",
"",
"ILL, PMMC"
]
] |
0705.1632 | Joakim Lundin | J. Lundin, L. Stenflo, G. Brodin, M. Marklund and P. K. Shukla | Circularly polarized waves in a plasma with vacuum polarization effects | 5 pages (To appear in Physics of Plasmas) | Phys. Plasmas 14 (2007) 064503 | 10.1063/1.2745303 | null | physics.plasm-ph | null | The theory for large amplitude circularly polarized waves propagating along
an external magnetic field is extended in order to include also vacuum
polarization effects. A general dispersion relation, which unites previous
results, is derived.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:02:38 GMT"
}
] | 2008-05-12T00:00:00 | [
[
"Lundin",
"J.",
""
],
[
"Stenflo",
"L.",
""
],
[
"Brodin",
"G.",
""
],
[
"Marklund",
"M.",
""
],
[
"Shukla",
"P. K.",
""
]
] |
0705.1633 | Nils Prause | N. Prause, D. Reimers, C. Fechner, E. Janknecht | The baryon density at z=0.9-1.9 - Tracing the warm-hot intergalactic
medium with broad Lyman alpha absorption | 6 pages, 1 figure, accepted for publication in A&A | A&A 470, 67-72 (2007) | 10.1051/0004-6361:20077283 | null | astro-ph | null | We present an analysis of the Lyman alpha forests of five quasar spectra in
the near UV. Properties of the intergalactic medium (IGM) at an intermediate
redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the
diffuse photoionised IGM and the warm-hot intergalactic medium (WHIM) are
traced to get constraints on the redshift evolution of the different phases of
the intergalactic gas. The baryon density of the diffuse IGM is determined with
photoionisation calculations under the assumption of local hydrostatic
equilibrium. We assume that the gas is ionised by a metagalactic background
radiation with a Haardt & Madau (2001) spectrum. The WHIM is traced with broad
Lyman alpha (BLA) absorption. The properties of a number of BLA detections are
studied. Under the assumption of collisional ionisation equilibrium a lower
limit to the baryon density could be estimated. It is found that the diffuse
photoionised IGM contains at least 25% of the total baryonic matter at
redshifts 1 < z < 2. For the WHIM a lower limit of 2.4% could be determined.
Furthermore the data indicates that the intergalactic gas is in a state of
evolution at z=1.5. We confirm that a considerable part of the WHIM is created
between z=1 and z=2.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:05:44 GMT"
}
] | 2007-07-04T00:00:00 | [
[
"Prause",
"N.",
""
],
[
"Reimers",
"D.",
""
],
[
"Fechner",
"C.",
""
],
[
"Janknecht",
"E.",
""
]
] |
0705.1634 | Lianyi He | Lianyi He and Pengfei Zhuang | Relativistic BCS-BEC Crossover at Finite Temperature and Its Application
to Color Superconductivity | 13 pages, 7 figures. V2: comparision with other theories and new
results on color superconductivity are added. V3: version published in PRD | Phys.Rev.D76:056003,2007 | 10.1103/PhysRevD.76.056003 | null | hep-ph astro-ph cond-mat.supr-con nucl-th | null | The non-relativistic $G_0 G$ formalism of BCS-BEC crossover at finite
temperature is extended to relativistic fermion systems. The uncondensed pairs
contribute a pseudogap to the fermion excitations. The theory recovers the BCS
mean field approximation at zero temperature and the non-relativistic results
in a proper limit. For massive fermions, when the coupling strength increases,
there exist two crossovers from the weak coupling BCS superfluid to the
non-relativistic BEC state and then to the relativistic BEC state. For color
superconductivity at moderate baryon density, the matter is in the BCS-BEC
crossover region, and the behavior of the pseudogap is quite similar to that
found in high temperature superconductors.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:11:29 GMT"
},
{
"version": "v2",
"created": "Sat, 14 Jul 2007 13:50:08 GMT"
},
{
"version": "v3",
"created": "Wed, 12 Sep 2007 15:17:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"He",
"Lianyi",
""
],
[
"Zhuang",
"Pengfei",
""
]
] |
0705.1635 | Thomas Prokscha | T. Prokscha, E. Morenzoni, D. G. Eshchenko, N. Garifianov, H.
Glueckler, R. Khasanov, H. Luetkens, A. Suter | Formation of hydrogen impurity states in silicon and insulators at low
implantation energies | 4 pages, 4 enscapulated postscript figures, uses revtex4 twocolumn
style to be published in Physical Review Letters | null | 10.1103/PhysRevLett.98.227401 | null | cond-mat.other | null | The formation of hydrogen-like muonium (Mu) has been studied as a function of
implantation energy in intrinsic Si, thin films of condensed van der Waals
gases (N2, Ne, Ar, Xe), fused and crystalline quartz and sapphire. By varying
the initial energy of positive muons (mu+) between 1 and 30 keV the number of
electron-hole pairs generated in the ionization track of the mu+ can be tuned
between a few and several thousand. The results show the strong suppression of
the formation of those Mu states that depend on the availability of excess
electrons. This indicates, that the role of H-impurity states in determining
electric properties of semiconductors and insulators depends on the way how
atomic H is introduced into the material.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:17:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Prokscha",
"T.",
""
],
[
"Morenzoni",
"E.",
""
],
[
"Eshchenko",
"D. G.",
""
],
[
"Garifianov",
"N.",
""
],
[
"Glueckler",
"H.",
""
],
[
"Khasanov",
"R.",
""
],
[
"Luetkens",
"H.",
""
],
[
"Suter",
"A.",
""
]
] |
0705.1636 | Florentin Millour | Florentin Millour (MPIFR), Romain Petrov (LUAN), Fabien Malbet (LUAN),
Eric Tatulli (OAA), Gilles Duvert (LUAN), G\'erard Zins (LUAN), Evelyne
Altariba (LUAN), Martin Vannier (ESO), Oscar Hernandez (LUAN), Gianluca Li
Causi (OAR) | AMBER on the VLTI: data processing and calibration issues | 10 pages | ESO calibration workshop 2007, Allemagne (24/01/2007) | 10.1007/978-3-540-76963-7_63 | null | astro-ph | null | We present here the current performances of the AMBER / VLTI instrument for
standard use and compare these with the offered modes of the instrument. We
show that the instrument is able to reach its specified precision only for
medium and high spectral resolution modes, differential observables and bright
objects. For absolute observables, the current achievable accuracy is strongly
limited by the vibrations of the Unit Telescopes, and also by the observing
procedure which does not take into account the night-long transfer function
monitoring. For low-resolution mode, the current limitation is more in the data
reduction side, since several effects negligible at medium spectral resolution
are not taken into account in the current pipeline. Finally, for faint objects
(SNR around 1 per spectral channel), electromagnetic interferences in the VLTI
interferometric laboratory with the detector electronics prevents currently to
get unbiased measurements. Ideas are under study to correct in the data
processing side this effect, but a hardware fix should be investigated
seriously since it limits seriously the effective limiting magnitude of the
instrument.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:28:36 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Millour",
"Florentin",
"",
"MPIFR"
],
[
"Petrov",
"Romain",
"",
"LUAN"
],
[
"Malbet",
"Fabien",
"",
"LUAN"
],
[
"Tatulli",
"Eric",
"",
"OAA"
],
[
"Duvert",
"Gilles",
"",
"LUAN"
],
[
"Zins",
"Gérard",
"",
"LUAN"
],
[
"Altariba",
"Evelyne",
"",
"LUAN"
],
[
"Vannier",
"Martin",
"",
"ESO"
],
[
"Hernandez",
"Oscar",
"",
"LUAN"
],
[
"Causi",
"Gianluca Li",
"",
"OAR"
]
] |
0705.1637 | Francesco Fontani | F. Fontani, I. Pascucci, P. Caselli, F. Wyrowski, R. Cesaroni, C.M.
Walmsley | Comparative study of complex N- and O-bearing molecules in hot molecular
cores | Accepted for publication in A&A, 56 pages | null | 10.1051/0004-6361:20077485 | null | astro-ph | null | We have observed several emission lines of two Nitrogen-bearing (C2H5CN and
C2H3CN) and two Oxygen-bearing (CH3OCH3 and HCOOCH3) molecules towards a sample
of well-known hot molecular cores (HMCs) in order to check whether the chemical
differentiation seen in the Orion-HMC and W3(H_2O) between O- and N-bearing
molecules is a general property of HMCs. With the IRAM-30m telescope we have
observed 12 HMCs in 21 bands, centered at frequencies from 86250 to 258280 MHz.
The rotational temperatures obtained range from ~100 to ~150 K in these HMCs.
Single Gaussian fits performed to unblended lines show a marginal difference in
the line peak velocities of the C2H5CN and CH3OCH3 lines, indicating a possible
spatial separation between the region traced by the two molecules. On the other
hand, neither the linewidths nor the rotational temperatures and column
densities confirm such a result. By comparing the abundance ratio of the pair
C2H5CN/C2H3CN with the predictions of theoretical models, we derive that the
age of our cores ranges between 3.7 and 5.9x10^{4} yrs. The abundances of
C2H5CN and C2H3CN are strongly correlated, as expected from theory which
predicts that C2H3CN is formed through gas phase reactions involving C2H5CN. A
correlation is also found between the abundances of C2H3CN and CH3OCH3, and
C2H5CN and CH3OCH3. In all tracers the fractional abundances increase with the
H_2 column density while they are not correlated with the gas temperature.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:43:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fontani",
"F.",
""
],
[
"Pascucci",
"I.",
""
],
[
"Caselli",
"P.",
""
],
[
"Wyrowski",
"F.",
""
],
[
"Cesaroni",
"R.",
""
],
[
"Walmsley",
"C. M.",
""
]
] |
0705.1638 | Sergei Sergeenkov | S. Sergeenkov, A.J.C. Lanfredi and F.M. Araujo-Moreira | Possible manifestation of spin fluctuations in the temperature behavior
of resistivity in Sm_{1.85}Ce_{0.15}CuO_4 thin films | 6 pages (REVTEX4), 2 EPS figures; accepted for publication in JETP
Letters | JETP Letters 85, 592 (2007) | 10.1134/S0021364007110148 | null | cond-mat.supr-con | null | A pronounced step-like (kink) behavior in the temperature dependence of
resistivity $\rho (T)$ is observed in the optimally-doped
$Sm_{1.85}Ce_{0.15}CuO_4$ thin films around $T_{sf}=87K$ and attributed to
manifestation of strong spin fluctuations induced by $Sm^{3+}$ moments with the
energy $\hbar \omega_{sf}=k_BT_{sf}\simeq 7meV$. In addition to fluctuation
induced contribution $\rho_{sf}(T)$ due to thermal broadening effects (of the
width $\omega_{sf}$), the experimental data are found to be well fitted
accounting for residual (zero-temperature) $\rho_{res}$, electron-phonon $\rho
_{e-ph}(T)=AT$ and electron-electron $\rho_{e-e}(T)=BT^2$ contributions. The
best fits produced $\omega_p=2.1meV$, $\tau_0^{-1}=9.5\times 10^{-14}s^{-1}$,
$\lambda =1.2$, and $E_F=0.2eV$ for estimates of the plasmon frequency, the
impurity scattering rate, electron-phonon coupling constant, and the Fermi
energy, respectively.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:46:06 GMT"
}
] | 2007-08-30T00:00:00 | [
[
"Sergeenkov",
"S.",
""
],
[
"Lanfredi",
"A. J. C.",
""
],
[
"Araujo-Moreira",
"F. M.",
""
]
] |
0705.1639 | Osmi Vilhu | Osmi Vilhu, Pasi Hakala, Linnea Hjalmarsdotter, Diana Hannikainen, Ada
Paizis and Michael McCollough | Modeling of orbital modulation of Cygnus X-3 by particle simulations | 4 pages (pdf), proceedings of the 6th INTEGRAL Workshop 'The Obscured
Universe', July 2-8 2006, ESA SP-622 | null | null | null | astro-ph | null | The formation of the circumbinary envelope of Cygnus X-3 was studied by
particle simulations of the WR (Wolf Rayet) companion wind. Light curves
resulting from electron scattering absorption in this envelope were computed
and compared with observed IBIS/ISGRI and BATSE light curves. The matching was
relatively good. For reasonable values of binary parameters (masses,
inclination) and wind velocities, a stable envelope was formed during a few
binary orbits. Assuming approximately 10^-6 solar mass/year for the rate of the
WR-wind, the observed light curves and accretion luminosity can be re-produced
(assuming Thomson scattering opacity in the ionized He-rich envelope). The
illuminated envelope can also model the CHANDRA-spectrum using the
photoionizing XSTAR-code. Furthermore, we discuss observed radial velocity
curves of IR emission lines in the context of simulated velocity fields and
find good agreement.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 12:47:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vilhu",
"Osmi",
""
],
[
"Hakala",
"Pasi",
""
],
[
"Hjalmarsdotter",
"Linnea",
""
],
[
"Hannikainen",
"Diana",
""
],
[
"Paizis",
"Ada",
""
],
[
"McCollough",
"Michael",
""
]
] |
0705.1640 | Alexander Schmidt | Alexander Schmidt, Hartmut Wachter | Spinor calculus for q-deformed quantum spaces I | 80 pages, LaTex, no figures | null | null | null | hep-th | null | The article is dedicated to q-deformed versions of spinor calculus. As a kind
of review, the most relevant properties of the two-dimensional quantum plane
are summarized. Additionally, the relationship between the quantum plane and
higher-dimensional quantum spaces like the q-deformed Euclidean space in four
dimensions or the q-deformed Minkowski space is outlined. These considerations
are continued by introducing q-analogs of the Pauli matrices. Their main
properties are discussed in detail and numerous relations that could prove
useful in physical applications are presented. In this respect, q-deformed
versions of the important Fierz identities are written down.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:05:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Schmidt",
"Alexander",
""
],
[
"Wachter",
"Hartmut",
""
]
] |
0705.1641 | N. G. Marchuk | N. G. Marchuk, D. S. Shirokov | Unitary spaces on Clifford algebras | 39 pages | Adv. Appl. Clifford Algebr., 18:2 (2008), 237-254 | 10.1007/s00006-008-0066-y | null | math-ph math.MP | null | For the complex Clifford algebra Cl(p,q) of dimension n=p+q we define a
Hermitian scalar product. This scalar product depends on the signature (p,q) of
Clifford algebra. So, we arrive at unitary spaces on Clifford algebras. With
the aid of Hermitian idempotents we suggest a new construction of, so called,
normal matrix representations of Clifford algebra elements. These
representations take into account the structure of unitary space on Clifford
algebra.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:07:02 GMT"
}
] | 2019-10-21T00:00:00 | [
[
"Marchuk",
"N. G.",
""
],
[
"Shirokov",
"D. S.",
""
]
] |
0705.1642 | T. Melde | B. Sengl, T. Melde, W. Plessas | Covariant calculation of strange decays of baryon resonances | 6 pages, 3 tables | Phys.Rev.D76:054008,2007 | 10.1103/PhysRevD.76.054008 | null | nucl-th | null | We present results for kaon decay widths of baryon resonances from a
relativistic study with constituent quark models. The calculations are done in
the point-form of Poincare-invariant quantum mechanics with a spectator-model
decay operator. We obtain covariant predictions of the Goldstone-boson-exchange
and a variant of the one-gluon-exchange constituent quark models for all kaon
decay widths of established baryon resonances. They are generally characterized
by underestimating the available experimental data. In particular, the widths
of kaon decays with increasing strangeness in the baryon turn out to be
extremely small. We also consider the nonrelativistic limit, leading to the
familiar elementary emission model, and demonstrate the importance of
relativistic effects. It is found that the nonrelativistic approach evidently
misses sensible influences from Lorentz boosts and some essential spin-coupling
terms.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:27:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sengl",
"B.",
""
],
[
"Melde",
"T.",
""
],
[
"Plessas",
"W.",
""
]
] |
0705.1643 | Kliment I. Kugel | A. O'Hare, F.V. Kusmartsev, K.I. Kugel, and M.S. Laad | Two-dimensional Ising model with competing interactions and its
application to clusters and arrays of $\pi$-rings and adiabatic quantum
computing | 32 pages, 22 figures, RevTex | null | 10.1103/PhysRevB.76.064528 | null | cond-mat.str-el cond-mat.stat-mech | null | We study planar clusters consisting of loops including a Josephson
$\pi$-junction ($\pi$-rings). Each $\pi$-ring carries a persistent current and
behaves as a classical orbital moment. The type of particular state associated
with the orientation of orbital moments at the cluster depends on the
interaction between these orbital moments and can be easily controlled, i.e. by
a bias current or by other means. We show that these systems can be described
by the two-dimensional Ising model with competing nearest-neighbor and diagonal
interactions and investigate the phase diagram of this model. The
characteristic features of the model are analyzed based on the exact solutions
for small clusters such as a 5-site square plaquette as well as on a mean-field
type approach for the infinite square lattice of Ising spins. The results are
compared with spin patterns obtained by Monte Carlo simulations for the 100
$\times$ 100 square lattice and with experiment. We show that the $\pi$-ring
clusters may be used as a new type of superconducting memory elements. The
obtained results may be verified in experiments and are applicable to adiabatic
quantum computing where the states are switched adiabatically with the slow
change of coupling constants.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 03:13:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"O'Hare",
"A.",
""
],
[
"Kusmartsev",
"F. V.",
""
],
[
"Kugel",
"K. I.",
""
],
[
"Laad",
"M. S.",
""
]
] |
0705.1644 | Roberto Alamino | Roberto C. Alamino and David Saad (NCRG, Aston University) | Statistical Mechanics Analysis of LDPC Coding in MIMO Gaussian Channels | 25 pages, 7 figures | null | 10.1088/1751-8113/40/41/001 | null | cond-mat.stat-mech | null | Using analytical methods of statistical mechanics, we analyse the typical
behaviour of a multiple-input multiple-output (MIMO) Gaussian channel with
binary inputs under LDPC network coding and joint decoding. The saddle point
equations for the replica symmetric solution are found in particular
realizations of this channel, including a small and large number of
transmitters and receivers. In particular, we examine the cases of a single
transmitter, a single receiver and the symmetric and asymmetric interference
channels. Both dynamical and thermodynamical transitions from the ferromagnetic
solution of perfect decoding to a non-ferromagnetic solution are identified for
the cases considered, marking the practical and theoretical limits of the
system under the current coding scheme. Numerical results are provided, showing
the typical level of improvement/deterioration achieved with respect to the
single transmitter/receiver result, for the various cases.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:31:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Alamino",
"Roberto C.",
"",
"NCRG, Aston University"
],
[
"Saad",
"David",
"",
"NCRG, Aston University"
]
] |
0705.1645 | Domenico Orlando | R. Dijkgraaf, D. Orlando, S. Reffert | Dimer Models, Free Fermions and Super Quantum Mechanics | minor corrections, reference added | null | null | null | hep-th math.QA | null | This note relates topics in statistical mechanics, graph theory and
combinatorics, lattice quantum field theory, super quantum mechanics and string
theory. We give a precise relation between the dimer model on a graph embedded
on a torus and the massless free Majorana fermion living on the same lattice. A
loop expansion of the fermion determinant is performed, where the loops turn
out to be compositions of two perfect matchings. These loop states are sorted
into co-chain groups using categorification techniques similar to the ones used
for categorifying knot polynomials. The Euler characteristic of the resulting
co-chain complex recovers the Newton polynomial of the dimer model. We
re-interpret this system as supersymmetric quantum mechanics, where
configurations with vanishing net winding number form the ground states.
Finally, we make use of the quiver gauge theory - dimer model correspondence to
obtain an interpretation of the loops in terms of the physics of D-branes
probing a toric Calabi-Yau singularity.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 11:32:32 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Nov 2007 13:29:06 GMT"
}
] | 2007-11-12T00:00:00 | [
[
"Dijkgraaf",
"R.",
""
],
[
"Orlando",
"D.",
""
],
[
"Reffert",
"S.",
""
]
] |
0705.1646 | Sascha Orlik | S. Orlik, M. Rapoport | Deligne-Lusztig varieties and period domains over finite fields | 16 pages, reference added to the paper of X. He (arXiv:0707.0259) in
which the affineness conjecture for DL-varieties is proved | null | null | null | math.AG math.RT | null | We prove that the Drinfeld halfspace is essentially the only Deligne-Lusztig
variety which is at the same time a period domain over a finite field. This is
done by comparing a cohomology vanishing theorem for DL-varieties, due to
Digne, Michel, and Rouquier, with a non-vanishing theorem for PD, due to the
first author. We also discuss an affineness criterion for DL-varieties.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:34:32 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Jul 2007 08:12:54 GMT"
}
] | 2007-07-08T00:00:00 | [
[
"Orlik",
"S.",
""
],
[
"Rapoport",
"M.",
""
]
] |
0705.1647 | Andrea Carati | A. Carati, L. Galgani, A. Giorgilli, S. Paleari | FPU phenomenon for generic initial data | null | Physical Review E 76, 022104 (2007) | 10.1103/PhysRevE.76.022104 | null | cond-mat.stat-mech | null | The well known FPU phenomenon (lack of attainment of equipartition of the
mode--energies at low energies, for some exceptional initial data) suggests
that the FPU model does not have the mixing property at low energies. We give
numerical indications that this is actually the case. This we show by computing
orbits for sets of initial data of full measure, sampled out from the
microcanonical ensemble by standard Montecarlo techniques. Mixing is tested by
looking at the decay of the autocorrelations of the mode--energies, and it is
found that the high--frequency modes have autocorrelations that tend instead to
positive values. Indications are given that such a nonmixing property survives
in the thermodynamic limit. It is left as an open problem whether mixing
obtains within time--scales much longer than the presently available ones.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:36:29 GMT"
}
] | 2014-03-12T00:00:00 | [
[
"Carati",
"A.",
""
],
[
"Galgani",
"L.",
""
],
[
"Giorgilli",
"A.",
""
],
[
"Paleari",
"S.",
""
]
] |
0705.1648 | Gorbovskoy Evgeny | V. Lipunov (1,2,3), E. Gorbovskoy (1,2,3) (1-Sternberg Astronomical
Institute, 2-Dept. of Physics of Moscow State University,3-Moscow Union
``Optic'') | An Extra Long X-Ray Plateau in a Gamma-Ray Burst and the Spinar Paradigm | 10 pages 3 figures | 2007ApJ...665L..97L | 10.1086/521099 | null | astro-ph | null | The recently discovered gamma-ray burst GRB 070110 displayed an extraordinary
X-ray afterglow with Xray radiation-i.e., an X-ray plateau-observed for 20,000
s. We show that the observed properties of the plateau can be naturally
interpreted in terms of the model with a spinar-a quasi-equilibrium collapsing
object whose equilibrium is maintained by the balance of centrifugal and
gravitational forces and whose evolution is determined by its magnetic field.
If this model is true, then for 1 hr, the Swift X-ray telescopes recorded
radiation from an object with a size smaller than the Schwarzschild radius!
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:15:04 GMT"
},
{
"version": "v2",
"created": "Wed, 16 May 2007 12:54:08 GMT"
},
{
"version": "v3",
"created": "Tue, 26 Jun 2007 10:42:34 GMT"
},
{
"version": "v4",
"created": "Fri, 7 Sep 2007 17:38:30 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Lipunov",
"V.",
""
],
[
"Gorbovskoy",
"E.",
""
]
] |
0705.1649 | Karl-Erik Eriksson | K.-E. Eriksson | Quantum Measurement as a Final-State Interaction with a Macroscopic
External System | 32 pages, 6 figures | null | null | null | quant-ph | null | A small quantum scattering system (the microsystem) is studied in interaction
with a large system (the macrosystem) described by unknown stochastic
variables. The interaction between the two systems is diagonal for the
microsystem in a certain orthonormal basis, and the interaction gives an
imprint on the macrosystem. Moreover, the interaction is assumed to involve
only small transfers of energy and momentum between the two systems (as
compared to typical energies/momenta within the microsystem). The analysis is
carried out within scattering theory. Calculated in the conventional way, the
transition amplitude for the whole system factorizes. The interaction taking
place within the macrosystem is assumed to depend on the stochastic variables
in such a way that, on the average, no particular basis vector state of the
microsystem is favoured. The density matrix is studied in a formalism which
includes generation of the ingoing state and absorption of the final state.
Then the dependence of the final state on the conventional scattering amplitude
for the microsystem is highly non-linear.
In the thermodynamic limit of the macrosystem, the density matrix of the
ensemble (of microsystem plus macrosystem) develops into a final state which
involves a set of macroscopically distinguishable states, each with the
microsystem in one of the basis vector states and the macrosystem in an
entangled state.
For an element of the ensemble, i.e., for a single measurement, the result is
instead a random walk, where the microsystem ends up in one of the basis vector
states (reduction of the wave packet).
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:44:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Eriksson",
"K. -E.",
""
]
] |
0705.1650 | Miroslava Dessauges-Zavadsky | M. Dessauges-Zavadsky (1), F. Calura (2), J. X. Prochaska (3), S.
D'Odorico (4), F. Matteucci (5,2) ((1) Geneva Observatory, Switzerland, (2)
INAF, Trieste, Italy, (3) UCO/Lick Observatory, USA, (4) ESO, Germany, (5)
Dipartimento di Astronomia, Trieste, Italy) | A new comprehensive set of elemental abundances in DLAs III. Star
formation histories | 19 pages, 11 figures, Accepted for publication in A&A | null | 10.1051/0004-6361:20077050 | null | astro-ph | null | We obtained comprehensive sets of elemental abundances for eleven damped
Ly-alpha systems (DLAs) at z_DLA=1.7-2.5. In Paper I of this series, we showed
for three DLA galaxies that we can derive their star formation histories and
ages from a detailed comparison of their intrinsic abundance patterns with
chemical evolution models. We determine in this paper the star formation
properties of six additional DLA galaxies. The derived results confirm that no
single star formation history explains the diverse sets of abundance patterns
in DLAs. We demonstrate that the various star formation histories reproducing
the DLA abundance patterns are typical of local irregular, dwarf starburst and
quiescent spiral galaxies. Independent of the star formation history, the DLAs
have a common characteristic of being weak star forming galaxies; models with
high star formation efficiencies are ruled out. All the derived DLA star
formation rates per unit area are moderate or low, with values between -3.2 <
log SFR < -1.1 M_sol yr^{-1} kpc^{-2}. The DLA abundance patterns require a
large spread in ages ranging from 20 Myr up to 3 Gyr. The oldest DLA in our
sample is observed at z_DLA=1.864 with an age estimated to more than 3 Gyr; it
nicely indicates that galaxies were already forming at z_f>10. But, most of the
DLAs show ages much younger than that of the Universe at the epoch of
observation. Young galaxies thus seem to populate the high redshift Universe at
z>2, suggesting relatively low redshifts of formation (z~3) for most
high-redshift galaxies. The DLA star formation properties are compared with
those of other high-redshift galaxies identified in deep imaging surveys with
the aim of obtaining a global picture of high-redshift objects.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:41:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dessauges-Zavadsky",
"M.",
""
],
[
"Calura",
"F.",
""
],
[
"Prochaska",
"J. X.",
""
],
[
"D'Odorico",
"S.",
""
],
[
"Matteucci",
"F.",
""
]
] |
0705.1651 | Shinya Ueda | S. Ueda, T. Okutsu, S. Ishii and Y. Takano | Switching Current Measurements of EuBa2Cu3Oy Intrinsic Josephson
Junctions | 3 pages, 5 figures | null | null | null | cond-mat.supr-con | null | We investigated the switching dynamics of two kinds of EuBa2Cu3Oy (Eu123)
intrinsic Josephson junctions (IJJs) with different anisotropy parameters gamma
(= (m*c/m*ab)1/2) tuned to 37 and 22. In contrast to weakly-coupled IJJs in
Bi2212, significant deviations from the thermally activated escape model of a
single-stack Josephson junction were observed in their switching current
distributions, P(I), due to the strongly-coupled nature of the Eu123 IJJs, The
P(I) of the two IJJs are found to be independent of temperature, below 1.4 K
and 4.2 K, respectively; which indicates the observation of macroscopic quantum
tunneling at high temperatures of liquid He.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:45:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ueda",
"S.",
""
],
[
"Okutsu",
"T.",
""
],
[
"Ishii",
"S.",
""
],
[
"Takano",
"Y.",
""
]
] |
0705.1652 | Jie Wu | Jie Wu (IECN) | Chen's double sieve, Goldbach's conjecture and the twin prime problem | null | Acta Arithmetica 114, no. 3 (2004) 215--273 | null | null | math.NT | null | We give a more comrehensive treatment of Chen's double sieve and improve
related constants in Goldbach's conjecture and the twin prime problem.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 13:55:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wu",
"Jie",
"",
"IECN"
]
] |
0705.1653 | Rahul Pandharipande | D. Maulik and R. Pandharipande | Gromov-Witten theory and Noether-Lefschetz theory | 48 pages, revised with new calculations for classical families of K3
surfaces, final version dedicated to J. Harris on the occasion of his 60th
birthday | null | null | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Noether-Lefschetz divisors in the moduli of K3 surfaces are the loci
corresponding to Picard rank at least 2. We relate the degrees of the
Noether-Lefschetz divisors in 1-parameter families of K3 surfaces to the
Gromov-Witten theory of the 3-fold total space. The reduced K3 theory and the
Yau-Zaslow formula play an important role. We use results of Borcherds and
Kudla-Millson for O(2,19) lattices to determine the Noether-Lefschetz degrees
in classical families of K3 surfaces of degrees 2, 4, 6 and 8. For the quartic
K3 surfaces, the Noether-Lefschetz degrees are proven to be the Fourier
coefficients of an explicitly computed modular form of weight 21/2 and level 8.
The interplay with mirror symmetry is discussed. We close with a conjecture on
the Picard ranks of moduli spaces of K3 surfaces.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:34:45 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jan 2010 18:42:00 GMT"
},
{
"version": "v3",
"created": "Sun, 11 Nov 2012 16:12:21 GMT"
}
] | 2012-11-13T00:00:00 | [
[
"Maulik",
"D.",
""
],
[
"Pandharipande",
"R.",
""
]
] |
0705.1654 | Steffen Hardt | Steffen Hardt, Sudarshan Tiwari, Axel Klar | Momentum Transfer to Nanoobjects between Parallel Heated Plates | 11 pages, figures included | null | null | null | physics.flu-dyn | null | A small-scale, trapezoidal rigid body in the gas-filled gap between two
parallel plates at different temperatures is considered. An analytical
expression for the force onto the body in the direction parallel to the plates
valid for an infinite Knudsen number is derived. Simultaneously, Monte-Carlo
simulations are performed allowing to extend the analysis to Knudsen numbers of
the order of one. The numerical and the analytical results show excellent
agreement, indicating that a temperature gradient orthogonal to the plates can
induce a significant force in parallel direction. This force is only slightly
reduced when a Knudsen number of one is considered. In the future, the
discovered effect may be exploited for the conversion of thermal into
mechanical energy in nanomachines.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:07:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hardt",
"Steffen",
""
],
[
"Tiwari",
"Sudarshan",
""
],
[
"Klar",
"Axel",
""
]
] |
0705.1655 | Guowu Yao | Guowu Yao | Existence of extremal Beltrami coefficients with non-constant modulus | To appear in Nagoya Math. J | null | null | Yao20040708 | math.CV | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Suppose $[\mu]_{T(\Delta)}$ is a point of the universal Teichm\"uller space
$T(\Delta)$. In 1998, it was shown by Bo\v{z}in et al. that there exists $\mu$
such that $\mu$ has non-constant modulus and is uniquely extremal in
$[\mu]_{T(\Delta)}$. It is a natural problem whether there is always an
extremal Beltrmai coefficient of constant modulus in $[\mu]_{T(\Delta)}$ if
$[\mu]_{T(\Delta)}$ admits more than one extremal Beltrami coefficient. The
purpose of this paper is to show that the answer is negative. An infinitesimal
version is also obtained. Extremal sets of extremal Beltrami coefficients are
considered and an open problem is proposed.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:09:10 GMT"
},
{
"version": "v2",
"created": "Sat, 24 Jan 2009 09:59:52 GMT"
}
] | 2009-01-24T00:00:00 | [
[
"Yao",
"Guowu",
""
]
] |
0705.1656 | Manfred Bohn | Julio Mateos-Langerak, Osdilly Giromus, Wim de Leeuw, Manfred Bohn,
Pernette J. Verschure, Gregor Kreth, Dieter W. Heermann, Roel van Driel and
Sandra Goetze | Chromatin Folding in Relation to Human Genome Function | null | null | null | null | q-bio.GN | null | Three-dimensional (3D) chromatin structure is closely related to genome
function, in particular transcription. However, the folding path of the
chromatin fiber in the interphase nucleus is unknown. Here, we systematically
measured the 3D physical distance between pairwise labeled genomic positions in
gene-dense, highly transcribed domains and gene-poor less active areas on
chromosomes 1 and 11 in G1 nuclei of human primary fibroblasts, using
fluorescence in situ hybridization. Interpretation of our results and those
published by others, based on polymer physics, shows that the folding of the
chromatin fiber can be described as a polymer in a globular state (GS),
maintained by intra-polymer attractive interactions that counteract
self-avoidance forces. The GS polymer model is able to describe chromatin
folding in as well the highly expressed domains as the lowly expressed ones,
indicating that they differ in Kuhn length and chromatin compaction. Each type
of genomic domain constitutes an ensemble of relatively compact globular
folding states, resulting in a considerable cellto- cell variation between
otherwise identical cells. We present evidence for different polymer folding
regimes of the chromatin fiber on the length scale of a few mega base pairs and
on that of complete chromosome arms (several tens of Mb). Our results present a
novel view on the folding of the chromatin fiber in interphase and open the
possibility to explore the nature of the intra-chromatin fiber interactions.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:12:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mateos-Langerak",
"Julio",
""
],
[
"Giromus",
"Osdilly",
""
],
[
"de Leeuw",
"Wim",
""
],
[
"Bohn",
"Manfred",
""
],
[
"Verschure",
"Pernette J.",
""
],
[
"Kreth",
"Gregor",
""
],
[
"Heermann",
"Dieter W.",
""
],
[
"van Driel",
"Roel",
""
],
[
"Goetze",
"Sandra",
""
]
] |
0705.1657 | Clare Burrage | C. Burrage, A.C. Davis | P-term Potentials from 4-D Supergravity | 21 pages, no figures | JHEP 0706:086,2007 | 10.1088/1126-6708/2007/06/086 | null | hep-th | null | P-term inflation arises in some models of brane inflation. Within N=2
supersymmetry the scalar potential contains a vector of Fayet-Iliopoulos (FI)
terms $\xi_i$. Depending on the direction of this vector it is possible to get
D-term and F-term inflation or a mix of these models. In this paper we review
the problems of embedding the P-term model in supergravity and show how these
can be solved by considering the truncation from an N=2 theory to N=1. We show
that with a simple gauging the scalar potential can include F-term or D-term
parts but not both. The gauging can be altered so that both F-terms and D-terms
containing FI constants can be included. In all cases we display the
inflationary trajectory and, if it exists, the supersymmetric minimum.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:12:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Burrage",
"C.",
""
],
[
"Davis",
"A. C.",
""
]
] |
0705.1658 | Aldo Procacci | Roberto Fernandez, Aldo Procacci, Benedetto Scoppola | The analyticity region of the hard sphere gas. Improved bounds | 4 pages, to appear in Journal of Statistical Physics | null | 10.1007/s10955-007-9352-7 | null | math-ph math.MP | null | We find an improved estimate of the radius of analyticity of the pressure of
the hard-sphere gas in $d$ dimensions. The estimates are determined by the
volume of multidimensional regions that can be numerically computed. For $d=2$,
for instance, our estimate is about 40% larger than the classical one.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:15:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fernandez",
"Roberto",
""
],
[
"Procacci",
"Aldo",
""
],
[
"Scoppola",
"Benedetto",
""
]
] |
0705.1659 | Megan Donahue | Megan Donahue, Ming Sun, Christopher P. O'Dea, G. Mark Voit, Kenneth
W. Cavagnolo | Star Formation, Radio Sources, Cooling X-ray Gas, and Galaxy
Interactions in the Brightest Cluster Galaxy in 2A0335+096 | Accepted AJ, July 2007 publication. Vol 134, p. 14-25 | Astron.J.134:14-25,2007 | 10.1086/518230 | null | astro-ph | null | We present deep emission-line imaging taken with the SOAR Optical Imaging
Camera of the brightest cluster galaxy (BCG) in the nearby (z=0.035) X-ray
cluster 2A0335+096. We analyze long-slit optical spectroscopy, archival VLA,
Chandra X-ray, and XMM UV data. 2A0335+096 is a bright, cool-core X-ray
cluster, once known as a cooling flow. Within the highly disturbed core
revealed by Chandra X-ray observations, 2A0335+096 hosts a highly structured
optical emission-line system. The redshift of the companion is within 100 km/s
of the BCG and has certainly interacted with the BCG, and is likely bound to
it. The comparison of optical and radio images shows curved filaments in
H-alpha emission surrounding the resolved radio source. The velocity structure
of the emission-line bar between the BCG nucleus and the companion galaxy
provides strong evidence for an interaction between the two in the last ~50
Myrs. The age of the radio source is similar to the interaction time, so this
interaction may have provoked an episode of radio activity. We estimate a star
formation rate of >7 solar mass/yr based on the Halpha and archival UV data, a
rate similar to, but somewhat lower than, the revised X-ray cooling rate of
10-30 solar masses/year estimated from XMM spectra by Peterson & workers. The
Halpha nebula is limited to a region of high X-ray surface brightness and cool
X-ray temperature. The detailed structures of H-alpha and X-ray gas differ. The
peak of the X-ray emission is not the peak of H-alpha emission, nor does it lie
in the BCG. The estimated age of the radio lobes and their interaction with the
optical emission-line gas, the estimated timescale for depletion and
accumulation of cold gas, and the dynamical time in the system are all similar,
suggesting a common trigger mechanism.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:40:09 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Donahue",
"Megan",
""
],
[
"Sun",
"Ming",
""
],
[
"O'Dea",
"Christopher P.",
""
],
[
"Voit",
"G. Mark",
""
],
[
"Cavagnolo",
"Kenneth W.",
""
]
] |
0705.1660 | Christian de Ronde | Graciela Domenech, Hector Freytes and Christian de Ronde | The Contextual Character of Modal Interpretations of Quantum Mechanics | 21 pages, no figures, preprint submitted to SHPMP | null | null | null | quant-ph | null | In this article we discuss the contextual character of quantum mechanics in
the framework of modal interpretations. We investigate its historical origin
and relate contemporary modal interpretations to those proposed by M. Born and
W. Heisenberg. We present then a general characterization of what we consider
to be a modal interpretation. Following previous papers in which we have
introduced modalities in the Kochen-Specker theorem, we investigate the
consequences of these theorems in relation to the modal interpretations of
quantum mechanics.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:20:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Domenech",
"Graciela",
""
],
[
"Freytes",
"Hector",
""
],
[
"de Ronde",
"Christian",
""
]
] |
0705.1661 | Christof Wetterich | C.Wetterich | Functional renormalization for quantum phase transitions with
non-relativistic bosons | 31 pages, new references | null | 10.1103/PhysRevB.77.064504 | null | cond-mat.supr-con astro-ph cond-mat.str-el hep-th | null | Functional renormalization yields a simple unified description of bosons at
zero temperature, in arbitrary space dimension $d$ and for $M$ complex fields.
We concentrate on nonrelativistic bosons and an action with a linear time
derivative. The ordered phase can be associated with a nonzero density of
(quasi) particles $n$. The behavior of observables and correlation functions in
the ordered phase depends crucially on the momentum $k_{ph}$, which is
characteristic for a given experiment. For the dilute regime $k_{ph}\gtrsim
n^{1/d}$ the quantum phase transition is simple, with the same ``mean field''
critical exponents for all $d$ and $M$. On the other hand, the dense regime
$k_{ph}\ll n^{1/d}$ reveals a rather rich spectrum of features, depending on
$d$ and $M$. In this regime one observes for $d\leq 3$ a crossover to a
relativistic action with second time derivatives. This admits order for $d>1$,
whereas $d=1$ shows a behavior similar to the low temperature phase of the
classical two-dimensional $O(2M)$-models.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:25:16 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 10:54:53 GMT"
},
{
"version": "v3",
"created": "Fri, 29 Feb 2008 15:16:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wetterich",
"C.",
""
]
] |
0705.1662 | Bogumi{\l} Pilecki | B. Pilecki, D. M. Szczygie{\l} | 13 New Eclipsing Binaries with Additional Variability in the ASAS
Catalogue | 10 pages, 12 figures, IBVS 5768 | 2007, IBVS, 5768 | null | null | astro-ph | null | We present 13 new ASAS eclipsing binaries that exhibit additional periodic
variability due to pulsations, eclipses with another period or spots. All
contact and semi-detached binaries from the ASAS Catalogue were investigated.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:46:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pilecki",
"B.",
""
],
[
"Szczygieł",
"D. M.",
""
]
] |
0705.1663 | Alexander I. Bobenko | Vsevolod E. Adler, Alexander I. Bobenko, Yuri B. Suris | Discrete nonlinear hyperbolic equations. Classification of integrable
cases | 19 pages | Funkt. Analiz Prilozh., 2009, 43, p. 3-21; English translation:
Funct. Anal. Appl., 2009, 43, p. 3-17. | null | null | nlin.SI | null | We consider discrete nonlinear hyperbolic equations on quad-graphs, in
particular on the square lattice. The fields are associated to the vertices and
an equation Q(x_1,x_2,x_3,x_4)=0 relates four fields at one quad. Integrability
of equations is understood as 3D-consistency. The latter is a possibility to
consistently impose equations of the same type on all the faces of a
three-dimensional cube. This allows to set these equations also on
multidimensional lattices Z^N. We classify integrable equations with complex
fields x, and Q affine-linear with respect to all arguments. The method is
based on analysis of singular solutions.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:51:19 GMT"
}
] | 2009-06-12T00:00:00 | [
[
"Adler",
"Vsevolod E.",
""
],
[
"Bobenko",
"Alexander I.",
""
],
[
"Suris",
"Yuri B.",
""
]
] |
0705.1664 | Simon Catterall | Simon Catterall and Francesco Sannino | Minimal Walking on the Lattice | 18 pages, 12 figures | Phys.Rev.D76:034504,2007 | 10.1103/PhysRevD.76.034504 | null | hep-lat hep-ph | null | We provide the first evidence of a walking dynamics for two color lattice
Yang-Mills theory with two Dirac flavors in the symmetric representation of the
gauge group.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:04:50 GMT"
}
] | 2010-04-06T00:00:00 | [
[
"Catterall",
"Simon",
""
],
[
"Sannino",
"Francesco",
""
]
] |
0705.1665 | Souichi Ishikawa | S. Ishikawa | Spin-dependent three-nucleon force effects on nucleon-deuteron
scattering | 12 pages, 6 figures, submitted to Phys. Rev. C | Phys.Rev.C75:061002,2007 | 10.1103/PhysRevC.75.061002 | null | nucl-th | null | We construct a phenomenological three-nucleon force (3NF) model that gives a
good description of polarization observables in elastic nucleon-deuteron
(N-$d$) scattering at a low energy together with a realistic nucleon-nucleon
force and a 3NF arising from the exchange of two pions. Parameters of the
model, which consists of spin-independent, spin-orbit, and tensor components,
are determined to reproduce the three-nucleon binding energy and polarization
observables in N-d scattering at 3 MeV. Predictions of the model 3NF on N-d
polarization observables at higher energies are examined, and effects of each
component on the observables are investigated.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 14:59:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ishikawa",
"S.",
""
]
] |
0705.1666 | O. Stenull | Fangfu Ye, Ranjan Mukhopadhyay, Olaf Stenull, and T. C. Lubensky | Semi-soft Nematic Elastomers and Nematics in Crossed Electric and
Magnetic Fields | 4 pages, 3 figures | Phys. Rev. Lett. 98, 147801 (2007) | 10.1103/PhysRevLett.98.147801 | null | cond-mat.soft | null | Nematic elastomers with a locked-in anisotropy direction exhibit semi-soft
elastic response characterized by a plateau in the stress-strain curve in which
stress does not change with strain. We calculate the global phase diagram for a
minimal model, which is equivalent to one describing a nematic in crossed
electric and magnetic fields, and show that semi-soft behavior is associated
with a broken symmetry biaxial phase and that it persists well into the
supercritical regime. We also consider generalizations beyond the minimal model
and find similar results.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:04:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ye",
"Fangfu",
""
],
[
"Mukhopadhyay",
"Ranjan",
""
],
[
"Stenull",
"Olaf",
""
],
[
"Lubensky",
"T. C.",
""
]
] |
0705.1667 | Lorenzo Iorio | Lorenzo Iorio | Prospects for measuring the moment of inertia of pulsar PSR J0737-3039A | LaTex2e, 5 pages (Elsevier two-column style), 1 table, no figures. To
appear in New Astronomy | NewAstron.14:40-43,2009 | 10.1016/j.newast.2008.04.008 | null | gr-qc astro-ph | null | Here we consider the possibility of measuring at 10% or better the moment of
inertia I of the J0737-3039A via the gravitomagnetic spin-orbit periastron
precession. It turns out that the prospect of measuring the moment of inertia
of PSR J0737-3039A at 10% accuracy or better seems unlikely given the
limitations to the precision with which the system's basic binary and
post-Keplerian parameters can be measured via radio timing.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:07:29 GMT"
},
{
"version": "v2",
"created": "Mon, 14 May 2007 11:40:52 GMT"
},
{
"version": "v3",
"created": "Tue, 15 May 2007 17:24:45 GMT"
},
{
"version": "v4",
"created": "Sun, 20 May 2007 20:28:53 GMT"
},
{
"version": "v5",
"created": "Sun, 3 Jun 2007 12:57:13 GMT"
},
{
"version": "v6",
"created": "Fri, 6 Jul 2007 12:27:08 GMT"
},
{
"version": "v7",
"created": "Mon, 16 Jul 2007 10:21:30 GMT"
},
{
"version": "v8",
"created": "Tue, 29 Apr 2008 22:20:29 GMT"
}
] | 2013-09-03T00:00:00 | [
[
"Iorio",
"Lorenzo",
""
]
] |
0705.1668 | Luis Santos | S. Sinha and L. Santos | Dipolar gases in quasi one-dimensional geometries | 4 pages, 3 eps figures | null | 10.1103/PhysRevLett.99.140406 | null | cond-mat.other | null | We analyze the physics of cold dipolar gases in quasi one-dimensional
geometries, showing that the confinement-induced scattering resonances produced
by the transversal trapping are crucially affected by the dipole-dipole
interaction. As a consequence, the dipolar interaction may drastically change
the properties of quasi-1D dipolar condensates, even for situations in which
the dipolar interaction would be completely overwhelmed by the short-range
interactions in a 3D environment.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:13:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sinha",
"S.",
""
],
[
"Santos",
"L.",
""
]
] |
0705.1669 | Bahtiyar Ozgur Sarioglu | S. Deser, O. Sarioglu, B. Tekin | Spherically symmetric solutions of Einstein + non-polynomial gravities | 6 pages, no figures, REVTeX 4 | Gen.Rel.Grav.40:1-7,2008 | 10.1007/s10714-007-0508-1 | null | gr-qc hep-th | null | We obtain the static spherically symmetric solutions of a class of
gravitational models whose additions to the General Relativity (GR) action
forbid Ricci-flat, in particular, Schwarzschild geometries. These theories are
selected to maintain the (first) derivative order of the Einstein equations in
Schwarzschild gauge. Generically, the solutions exhibit both horizons and a
singularity at the origin, except for one model that forbids spherical symmetry
altogether. Extensions to arbitrary dimension with a cosmological constant,
Maxwell source and Gauss-Bonnet terms are also considered.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:18:51 GMT"
}
] | 2008-11-07T00:00:00 | [
[
"Deser",
"S.",
""
],
[
"Sarioglu",
"O.",
""
],
[
"Tekin",
"B.",
""
]
] |
0705.1670 | Hang Wong | Zhi-De Chen, Hang Wong | Artifact of the phonon-induced localization by variational calculations
in the spin-boson model | 9 pages, 7 figures | Phys. Rev. B 78, 064308 (2008) | 10.1103/PhysRevB.78.064308 | null | cond-mat.other | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present energy and free energy analyses on all variational schemes used in
the spin-boson model at both T=0 and $T\neq0$. It is found that all the
variational schemes have fail points, at where the variational schemes fail to
provide a lower energy (or a lower free energy at $T\neq0$) than the
displaced-oscillator ground state and therefore the variational ground state
becomes unstable, which results in a transition from a variational ground state
to a displaced oscillator ground state when the fail point is reached. Such
transitions are always misidentied as crossover from a delocalized to localized
phases in variational calculations, leading to an artifact of phonon-induced
localization. Physics origin of the fail points and explanations for different
transition behaviors with different spectral functions are found by studying
the fail points of the variational schemes in the single mode case.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:20:25 GMT"
},
{
"version": "v2",
"created": "Sat, 1 Sep 2007 04:47:05 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Jun 2008 04:32:17 GMT"
}
] | 2008-08-29T00:00:00 | [
[
"Chen",
"Zhi-De",
""
],
[
"Wong",
"Hang",
""
]
] |
0705.1671 | Valerio Biancalana | J.Belfi, G.Bevilacqua, V.Biancalana, Y.Dancheva, L.Moi | All optical sensor for automated magnetometry based on Coherent
Population Trapping | 8 pages, 10 figures, appearing in JOSA B (7?) 2007 | JOSA B 24 (7) (2007), pages 1482-1489 | 10.1364/JOSAB.24.001482 | null | physics.atom-ph physics.ins-det | null | An automated magnetometer suitable for long lasting measurement under stable
and controllable experimental conditions has been implemented. The device is
based on Coherent Population Trapping (CPT) produced by a multi-frequency
excitation. CPT resonance is observed when a frequency comb, generated by diode
laser current modulation, excites Cs atoms confined in a
$\pi/4\times(2.5)^2\times1 \textrm{cm}^3$, 2 Torr $N_2$ buffered cell. A fully
optical sensor is connected through an optical fiber to the laser head allowing
for truly remote sensing and minimization of the field perturbation. A detailed
analysis of the CPT resonance parameters as a function of the optical detuning
has been made in order to get high sensitivity measurements. The magnetic field
monitoring performances and the best sensitivity obtained in a balanced
differential configuration of the sensor are presented.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:28:53 GMT"
}
] | 2014-11-13T00:00:00 | [
[
"Belfi",
"J.",
""
],
[
"Bevilacqua",
"G.",
""
],
[
"Biancalana",
"V.",
""
],
[
"Dancheva",
"Y.",
""
],
[
"Moi",
"L.",
""
]
] |
0705.1672 | Tshilidzi Marwala | L. Mdlazi, T. Marwala, C.J. Stander, C. Scheffer and P.S. Heyns | Principal Component Analysis and Automatic Relevance Determination in
Damage Identification | 6 pages | null | null | null | cs.CE | null | This paper compares two neural network input selection schemes, the Principal
Component Analysis (PCA) and the Automatic Relevance Determination (ARD) based
on Mac-Kay's evidence framework. The PCA takes all the input data and projects
it onto a lower dimension space, thereby reduc-ing the dimension of the input
space. This input reduction method often results with parameters that have
significant influence on the dynamics of the data being diluted by those that
do not influence the dynamics of the data. The ARD selects the most relevant
input parameters and discards those that do not contribute significantly to the
dynamics of the data being modelled. The ARD sometimes results with important
input parameters being discarded thereby compromising the dynamics of the data.
The PCA and ARD methods are implemented together with a Multi-Layer-Perceptron
(MLP) network for fault identification in structures and the performance of the
two methods is as-sessed. It is observed that ARD and PCA give similar
accu-racy levels when used as input-selection schemes. There-fore, the choice
of input-selection scheme is dependent on the nature of the data being
processed.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:35:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mdlazi",
"L.",
""
],
[
"Marwala",
"T.",
""
],
[
"Stander",
"C. J.",
""
],
[
"Scheffer",
"C.",
""
],
[
"Heyns",
"P. S.",
""
]
] |
0705.1673 | Tshilidzi Marwala | L. Mdlazi, C.J. Stander, P.S. Heyns and T. Marwala | Using artificial intelligence for data reduction in mechanical
engineering | 6 pages | null | null | null | cs.CE cs.AI cs.NE | null | In this paper artificial neural networks and support vector machines are used
to reduce the amount of vibration data that is required to estimate the Time
Domain Average of a gear vibration signal. Two models for estimating the time
domain average of a gear vibration signal are proposed. The models are tested
on data from an accelerated gear life test rig. Experimental results indicate
that the required data for calculating the Time Domain Average of a gear
vibration signal can be reduced by up to 75% when the proposed models are
implemented.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:49:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mdlazi",
"L.",
""
],
[
"Stander",
"C. J.",
""
],
[
"Heyns",
"P. S.",
""
],
[
"Marwala",
"T.",
""
]
] |
0705.1674 | Tshilidzi Marwala | Lukasz A Machowski, Tshilidzi Marwala | Evolutionary Optimisation Methods for Template Based Image Registration | 6 pages | null | null | null | cs.CE cs.CV | null | This paper investigates the use of evolutionary optimisation techniques to
register a template with a scene image. An error function is created to measure
the correspondence of the template to the image. The problem presented here is
to optimise the horizontal, vertical and scaling parameters that register the
template with the scene. The Genetic Algorithm, Simulated Annealing and
Particle Swarm Optimisations are compared to a Nelder-Mead Simplex optimisation
with starting points chosen in a pre-processing stage. The paper investigates
the precision and accuracy of each method and shows that all four methods
perform favourably for image registration. SA is the most precise, GA is the
most accurate. PSO is a good mix of both and the Simplex method returns local
minima the most. A pre-processing stage should be investigated for the
evolutionary methods in order to improve performance. Discrete versions of the
optimisation methods should be investigated to further improve computational
performance.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:51:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Machowski",
"Lukasz A",
""
],
[
"Marwala",
"Tshilidzi",
""
]
] |
0705.1675 | Alexander Schmidt | Alexander Schmidt, Hartmut Wachter | Spinor calculus for q-deformed quantum spaces II | 69 pages, LaTex, no figures | null | null | null | hep-th | null | This is the second part of an article about q-deformed analogs of spinor
calculus. The considerations refer to quantum spaces of physical interest, i.e.
q-deformed Euclidean space in three or four dimensions as well as q-deformed
Minkowski space. The Clifford algebras corresponding to these quantum spaces
are treated. Especially, their commutation relations and their Hopf structures
are written down. Bases of the four-dimensional Clifford algebras are
constructed and their properties are discussed. Matrix representations of the
Clifford algebras lead to q-deformed Dirac-matrices for the four-dimensional
quantum spaces. Moreover, q-analogs of the four-dimensional spin matrices are
presented. A very complete set of trace relations and rearrangement formulae
concerning spin and Dirac-matrices is given. Dirac spinors together with their
bilinear covariants are defined. Their behavior under q-deformed Lorentz
transformation is discussed in detail.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:47:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Schmidt",
"Alexander",
""
],
[
"Wachter",
"Hartmut",
""
]
] |
0705.1676 | Steffen J. Glaser | Amr F. Fahmy, Raimund Marx, Wolfgang Bermel, Steffen J. Glaser | Thermal Equilibrium as an Initial State for Quantum Computation by NMR | including 4 figures | null | 10.1103/PhysRevA.78.022317 | null | quant-ph | null | We present a method of using a nuclear magnetic resonance computer to solve
the Deutsch-Jozsa problem in which: (1) the number of molecules in the NMR
sample is irrelevant to the number of qubits available to an NMR quantum
computer, and (2) the initial state is chosen to be the state of thermal
equilibrium, thereby avoiding the preparation of pseudopure states and the
resulting exponential loss of signal as the number of qubits increases. The
algorithm is described along with its experimental implementation using four
active qubits. As expected, measured spectra demonstrate a clear distinction
between constant and balanced functions.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:49:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fahmy",
"Amr F.",
""
],
[
"Marx",
"Raimund",
""
],
[
"Bermel",
"Wolfgang",
""
],
[
"Glaser",
"Steffen J.",
""
]
] |
0705.1677 | Eric Stempels | H.C. Stempels, A. Collier Cameron, L. Hebb, B. Smalley and S. Frandsen | WASP-1: A lithium- and metal-rich star with an oversized planet | Accepted for publication in MNRAS. 6 pages, 4 figures | Mon.Not.Roy.Astron.Soc.379:773-778,2007 | 10.1111/j.1365-2966.2007.11976.x | null | astro-ph | null | In this paper we present our results of a comprehensive spectroscopicanalysis
of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/-
45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high
abundance of lithium, log n(Li) = 2.91 +/- 0.05. These parameters suggests an
age for the system of 1-3 Gyr and a stellar mass of 1.25-1.35 M_sun. This means
that WASP-1 has properties very similar to those of HD 149026, the host star
for the highest density planet yet detected. Moreover, their planets orbit at
comparable distances and receive comparable irradiating fluxes from their host
stars. However, despite the similarity of WASP-1 with HD 149026, their planets
have strongly different densities. This suggests that gas-giant planet density
is not a simple function of host-star metallicity or of radiation environment
at ages of ~2 Gyr.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:59:43 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Stempels",
"H. C.",
""
],
[
"Cameron",
"A. Collier",
""
],
[
"Hebb",
"L.",
""
],
[
"Smalley",
"B.",
""
],
[
"Frandsen",
"S.",
""
]
] |
0705.1678 | Antonio Moro | D. Escrig, A.M. Sanchez-Benitez, A.M. Moro, M.A.G. Alvarez, M.V.
Andres, C. Angulo, M.J.G. Borge, J. Cabrera, S. Cherubini, P. Demaret, J.M.
Espino, P. Figuera, M. Freer, J.E. Garcia-Ramos, J. Gomez-Camacho, M.Gulino,
O.R. Kakuee, I. Martel, C. Metelko, F. Perez-Bernal, J. Rahighi, K. Rusek, D.
Smirnov, O. Tengblad, and V. Ziman | alpha-particle production in the scattering of 6He by 208Pb at energies
around the Coulomb barrier | 20 pages, 5 figures. Nuclear Physics A792 (2007) 2-17 | Nucl.Phys.A792:2-17,2007 | 10.1016/j.nuclphysa.2007.05.012 | null | nucl-ex nucl-th | null | New experimental data from the scattering of 6He+208Pb at energies around and
below the Coulomb barrier are presented. The yield of breakup products coming
from projectile fragmentation is dominated by a strong group of $\alpha$
particles.
The energy and angular distributions of this group have been analyzed and
compared with theoretical calculations. This analysis indicates that the
$\alpha$ particles emitted at backward angles in this reaction are mainly due
to two-neutron transfer to weakly bound states of the final nucleus.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:53:37 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Nov 2007 13:36:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Escrig",
"D.",
""
],
[
"Sanchez-Benitez",
"A. M.",
""
],
[
"Moro",
"A. M.",
""
],
[
"Alvarez",
"M. A. G.",
""
],
[
"Andres",
"M. V.",
""
],
[
"Angulo",
"C.",
""
],
[
"Borge",
"M. J. G.",
""
],
[
"Cabrera",
"J.",
""
],
[
"Cherubini",
"S.",
""
],
[
"Demaret",
"P.",
""
],
[
"Espino",
"J. M.",
""
],
[
"Figuera",
"P.",
""
],
[
"Freer",
"M.",
""
],
[
"Garcia-Ramos",
"J. E.",
""
],
[
"Gomez-Camacho",
"J.",
""
],
[
"Gulino",
"M.",
""
],
[
"Kakuee",
"O. R.",
""
],
[
"Martel",
"I.",
""
],
[
"Metelko",
"C.",
""
],
[
"Perez-Bernal",
"F.",
""
],
[
"Rahighi",
"J.",
""
],
[
"Rusek",
"K.",
""
],
[
"Smirnov",
"D.",
""
],
[
"Tengblad",
"O.",
""
],
[
"Ziman",
"V.",
""
]
] |
0705.1679 | Marta Sales-Pardo | M. Sales-Pardo, R. Guimera, A. Moreira, and L. Amaral | Extracting the hierarchical organization of complex systems | Figures in screen resolution. Version with full resolution figures
available at
http://amaral.chem-eng.northwestern.edu/Publications/Papers/sales-pardo-2007.pdf | null | 10.1073/pnas.0703740104 | null | physics.soc-ph | null | Extracting understanding from the growing ``sea'' of biological and
socio-economic data is one of the most pressing scientific challenges facing
us. Here, we introduce and validate an unsupervised method that is able to
accurately extract the hierarchical organization of complex biological, social,
and technological networks. We define an ensemble of hierarchically nested
random graphs, which we use to validate the method. We then apply our method to
real-world networks, including the air-transportation network, an electronic
circuit, an email exchange network, and metabolic networks. We find that our
method enables us to obtain an accurate multi-scale descriptions of a complex
system.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:55:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sales-Pardo",
"M.",
""
],
[
"Guimera",
"R.",
""
],
[
"Moreira",
"A.",
""
],
[
"Amaral",
"L.",
""
]
] |
0705.1680 | Tshilidzi Marwala | Michael Maio Pires, Tshilidzi Marwala | Option Pricing Using Bayesian Neural Networks | 7 pages | null | null | null | cs.CE cs.NE | null | Options have provided a field of much study because of the complexity
involved in pricing them. The Black-Scholes equations were developed to price
options but they are only valid for European styled options. There is added
complexity when trying to price American styled options and this is why the use
of neural networks has been proposed. Neural Networks are able to predict
outcomes based on past data. The inputs to the networks here are stock
volatility, strike price and time to maturity with the output of the network
being the call option price. There are two techniques for Bayesian neural
networks used. One is Automatic Relevance Determination (for Gaussian
Approximation) and one is a Hybrid Monte Carlo method, both used with
Multi-Layer Perceptrons.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 15:55:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pires",
"Michael Maio",
""
],
[
"Marwala",
"Tshilidzi",
""
]
] |
0705.1681 | Cheng-Pang Liu | C.-P. Liu, M. J. Ramsey-Musolf, W. C. Haxton, R. G. E. Timmermans, and
A. E. L. Dieperink | Atomic Electric Dipole Moments: The Schiff Theorem and Its Corrections | 31 pages, 2 figures, typeset by REVTeX | Phys.Rev.C76:035503,2007 | 10.1103/PhysRevC.76.035503 | LA-UR-07-2262, Caltech MAP-311 | nucl-th hep-ph | null | Searches for the permanent electric dipole moments (EDMs) of diamagnetic
atoms provide powerful probes of CP-violating hadronic and semileptonic
interactions. The theoretical interpretation of such experiments, however,
requires careful implementation of a well-known theorem by Schiff that implies
a vanishing net EDM for an atom built entirely from point-like, nonrelativistic
constituents that interact only electrostatically. Any experimental observation
of a nonzero atomic EDM would result from corrections to the point-like,
nonrelativistic, electrostatic assumption. We reformulate Schiff's theorem at
the operator level and delineate the electronic and nuclear operators whose
atomic matrix elements generate corrections to "Schiff screening". We obtain a
form for the operator responsible for the leading correction associated with
finite nuclear size -- the so-called "Schiff moment" operator -- and observe
that it differs from the corresponding operator used in previous Schiff moment
computations. We show that the more general Schiff moment operator reduces to
the previously employed operator only under certain approximations that are not
generally justified. We also identify other corrections to Schiff screening
that may not be included properly in previous theoretical treatments. We
discuss practical considerations for obtaining a complete computation of
corrections to Schiff screening in atomic EDM calculations.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:07:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liu",
"C. -P.",
""
],
[
"Ramsey-Musolf",
"M. J.",
""
],
[
"Haxton",
"W. C.",
""
],
[
"Timmermans",
"R. G. E.",
""
],
[
"Dieperink",
"A. E. L.",
""
]
] |
0705.1682 | Giuseppe Durisi | Giuseppe Durisi, Helmut B\"olcskei, Shlomo Shamai (Shitz) | Capacity of Underspread Noncoherent WSSUS Fading Channels under Peak
Signal Constraints | To be presented at IEEE Int. Symp. Inf. Theory 2007, Nice, France | null | 10.1109/ISIT.2007.4557219 | null | cs.IT math.IT | null | We characterize the capacity of the general class of noncoherent underspread
wide-sense stationary uncorrelated scattering (WSSUS) time-frequency-selective
Rayleigh fading channels, under peak constraints in time and frequency and in
time only. Capacity upper and lower bounds are found which are explicit in the
channel's scattering function and allow to identify the capacity-maximizing
bandwidth for a given scattering function and a given peak-to-average power
ratio.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:01:09 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Durisi",
"Giuseppe",
"",
"Shitz"
],
[
"Bölcskei",
"Helmut",
"",
"Shitz"
],
[
"Shamai",
"Shlomo",
"",
"Shitz"
]
] |
0705.1683 | Alexander Schmidt | Alexander Schmidt, Hartmut Wachter | q-Deformed Superalgebras | 38 pages, LateX, no figures, corrected typos | JHEP 0712:035,2007 | 10.1088/1126-6708/2007/12/035 | null | hep-th | null | The article deals with q-analogs of the three- and four-dimensional Euclidean
superalgebra and the Poincare superalgebra.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:03:30 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Sep 2007 12:02:37 GMT"
}
] | 2009-04-22T00:00:00 | [
[
"Schmidt",
"Alexander",
""
],
[
"Wachter",
"Hartmut",
""
]
] |
0705.1684 | Chao-Yang Lu | Chao-Yang Lu, Daniel E. Browne, Tao Yang, Jian-Wei Pan | Demonstration of Shor's quantum factoring algorithm using photonic
qubits | small changes over v2; to appear in PRL | Phys. Rev. Lett. 99, 250504 (2007) | 10.1103/PhysRevLett.99.250504 | null | quant-ph physics.optics | null | We report an experimental demonstration of a complied version of Shor's
algorithm using four photonic qubits. We choose the simplest instance of this
algorithm, that is, factorization of N=15 in the case that the period $r=2$ and
exploit a simplified linear optical network to coherently implement the quantum
circuits of the modular exponential execution and semi-classical quantum
Fourier transformation. During this computation, genuine multiparticle
entanglement is observed which well supports its quantum nature. This
experiment represents a step toward full realization of Shor's algorithm and
scalable linear optics quantum computation.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:04:54 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Aug 2007 15:47:21 GMT"
},
{
"version": "v3",
"created": "Sun, 16 Dec 2007 13:39:44 GMT"
}
] | 2008-10-16T00:00:00 | [
[
"Lu",
"Chao-Yang",
""
],
[
"Browne",
"Daniel E.",
""
],
[
"Yang",
"Tao",
""
],
[
"Pan",
"Jian-Wei",
""
]
] |
0705.1685 | Sanjeev S. Seahra | Antonio Cardoso, Takashi Hiramatsu, Kazuya Koyama, and Sanjeev S.
Seahra | Scalar perturbations in braneworld cosmology | 17 pages, 7 figures | JCAP 0707:008,2007 | 10.1088/1475-7516/2007/07/008 | null | astro-ph gr-qc hep-th | null | We study the behaviour of scalar perturbations in the radiation-dominated era
of Randall-Sundrum braneworld cosmology by numerically solving the coupled bulk
and brane master wave equations. We find that density perturbations with
wavelengths less than a critical value (set by the bulk curvature length) are
amplified during horizon re-entry. This means that the radiation era matter
power spectrum will be at least an order of magnitude larger than the
predictions of general relativity (GR) on small scales. Conversely, we
explicitly confirm from simulations that the spectrum is identical to GR on
large scales. Although this magnification is not relevant for the cosmic
microwave background or measurements of large scale structure, it will have
some bearing on the formation of primordial black holes in Randall-Sundrum
models.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:24:12 GMT"
}
] | 2009-05-18T00:00:00 | [
[
"Cardoso",
"Antonio",
""
],
[
"Hiramatsu",
"Takashi",
""
],
[
"Koyama",
"Kazuya",
""
],
[
"Seahra",
"Sanjeev S.",
""
]
] |
0705.1686 | Sergei Nayakshin | Sergei Nayakshin and Andrew King (Leicester) | Forced accretion in stochastically fed AGN and quasars | 7 pages, submitted to MNRAS | null | null | null | astro-ph | null | Steady state accretion discs larger than ~ 0.01-0.1 pc are known to be
gravitationally unstable for the accretion rates needed to explain
super-massive black hole (SMBH) activity. We propose that SMBH are fed by a
succession of mass deposition events with randomly directed angular momenta.
Because of incomplete angular momentum cancellation a warped accretion disc
forms in the inner few parsec. The orientation of the disc performs a random
walk. Deposition of new material promotes SMBH accretion at rates much faster
than viscous. Observational implications of this picture include: (i) lighter
accretion discs that can fuel AGN and quasars and yet avoid star formation at R
>> 0.1 pc; (ii) star formation inside the disc is not a function of mass
accretion rate only. It can take place at high or low accretion rates, e.g.,
when too few clouds arrive in the inner region. An example of this might be the
central parsec of our Galaxy. (iii) The discs can form Compton-thick obscuring
structures of ~ parsec size as required in AGN unification models; (iv) faster
black hole growth resulting from misalignment of the disc and the black hole
spin in the early Universe; (v) Isotropic deposition of SMBH energy and
momentum feedback in the galaxy bulge. This may help explain the high
efficiency with which it seems to be operating in the Universe. (vi) No
correlation between SMBH activity and the presence of kiloparsec scale bars or
gaseous discs in galactic bulges; (vii) Bodily collisions between gaseous
components of merging galaxies facilitate production of gas streams feeding the
centre of the combined galaxy. Mergers should thus be catalysts of SMBH growth.
(viii) Conversely, galaxies experiencing fewer mergers are more likely to form
massive nuclear star clusters than feed their SMBHs.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:51:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nayakshin",
"Sergei",
"",
"Leicester"
],
[
"King",
"Andrew",
"",
"Leicester"
]
] |
0705.1687 | Cheikh Ndiaye birahim | Cheikh Birahim Ndiaye | Existence results for mean field equations with turbulence | null | null | null | null | math.AP | null | In this paper we consider the following form of the so-called Mean field
equation arising from the statistical mechanics description of two dimensional
turbulence \begin{equation}\label{eq:study} - \D_g u = \rho_1
(\frac{e^{u}}{\int_\Sig e^{u} dV_g}-1)-\rho_2
(\frac{e^{-u}}{\int_\Sig e^{-u} dV_g} - 1) \end{equation} on a given closed
orientable Riemannian surface ($\Sigma, g$) with volume 1, where $\rho_1,
\rho_2$ are real parameters. Exploiting the variational structure of the
problem and running a min-max scheme introduced by Djadli and Malchiodi, we
prove that if $k$ is a positive integer, $\rho_1$ and
$\rho_2$ two real numbers such that $\rho_1\in (8k\pi, 8(k+1)\pi)$ and
$\rho_2<4\pi$ then $\eqref{eq:study}$ is solvable.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:18:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ndiaye",
"Cheikh Birahim",
""
]
] |
0705.1688 | Claus Kiefer | Alexander Kamenshchik, Claus Kiefer, Barbara Sandhoefer | Quantum cosmology with big-brake singularity | 24 pages, 7 figures, figures improved, references added, conceptual
clarifications included | Phys.Rev.D76:064032,2007 | 10.1103/PhysRevD.76.064032 | null | gr-qc | null | We investigate a cosmological model with a big-brake singularity in the
future: while the first time derivative of the scale factor goes to zero, its
second time derivative tends to minus infinity. Although we also discuss the
classical version of the model in some detail, our main interest lies in its
quantization. We formulate the Wheeler-DeWitt equation and derive solutions
describing wave packets. We show that all such solutions vanish in the region
of the classical singularity, a behaviour which we interpret as singularity
avoidance. We then discuss the same situation in loop quantum cosmology. While
this leads to a different factor ordering, the singularity is there avoided,
too.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:19:41 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Oct 2007 10:38:47 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kamenshchik",
"Alexander",
""
],
[
"Kiefer",
"Claus",
""
],
[
"Sandhoefer",
"Barbara",
""
]
] |
0705.1689 | Dmitry Garanin | R. Yanes, O. Chubykalo-Fesenko, H. Kachkachi, D. A. Garanin, R. Evans,
and R. W. Chantrell | Effective anisotropies and energy barriers of magnetic nanoparticles
with Neel surface anisotropy | 15 PR pages, 19 Figure captions. Get the correct file from
http://www.lehman.edu/faculty/dgaranin/EffectiveAnisotropies.pdf | Phys. Rev. B 76, 064416 -(13) (2007) | 10.1103/PhysRevB.76.064416 | null | cond-mat.stat-mech cond-mat.mtrl-sci | null | Magnetic nanoparticles with Neel surface anisotropy, different internal
structures, surface arrangements and elongation are modelled as many-spin
systems. The results suggest that the energy of many-spin nanoparticles cut
from cubic lattices can be represented by an effective one-spin potential
containing uniaxial and cubic anisotropies. It is shown that the values and
signs of the corresponding constants depend strongly on the particle's surface
arrangement, internal structure and elongation. Particles cut from a simple
cubic lattice have the opposite sign of the effective cubic term, as compared
to particles cut from the face-centered cubic lattice. Furthermore, other
remarkable phenomena are observed in nanoparticles with relatively strong
surface effects: (i) In elongated particles surface effects can change the sign
of the uniaxial anisotropy. (ii) In symmetric particles (spherical and
truncated octahedral) with cubic core anisotropy surface effects can change its
sign. We also show that the competition between the core and surface
anisotropies leads to a new energy that contributes to both the 2nd- and
4th-order effective anisotropies.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 19:48:09 GMT"
}
] | 2008-05-06T00:00:00 | [
[
"Yanes",
"R.",
""
],
[
"Chubykalo-Fesenko",
"O.",
""
],
[
"Kachkachi",
"H.",
""
],
[
"Garanin",
"D. A.",
""
],
[
"Evans",
"R.",
""
],
[
"Chantrell",
"R. W.",
""
]
] |
0705.1690 | Laura Luzzi | Laura Luzzi, Stefano Marmi, Hitoshi Nakada, Rie Natsui | Generalized Brjuno functions associated to $\alpha$-continued fractions | 19 pages, 4 figures | null | null | null | math.DS math.NT | null | For \alpha in the interval [0,1], we consider the one-parameter family of
\alpha-continued fraction maps, which include the Gauss map (\alpha=1) and the
nearest integer (\alpha=1/2) and by-excess (\alpha=0) continued fraction maps.
To each of these expansions, and to each choice of a positive function u on the
interval I_\alpha=(0,max(\alpha,1-\alpha)) we associate a generalized Brjuno
function B_(\alpha,u)(x). For \alpha=1/2 or \alpha=1, and u(x)=-\log(x), these
functions were introduced by Yoccoz in his work on the linearization of
holomorphic maps. Their regularity properties, including BMO regularity and
their extension to the complex plane, have been thoroughly investigated. We
compare the functions obtained with different values of \alpha and we prove
that the set of (\alpha,u)-Brjuno numbers does not depend on the choice of
\alpha provided that \alpha>0. We then consider the case \alpha=0,
u(x)=-\log(x) and we prove that x is a Brjuno number (for \alpha> 0) if and
only if both x and -x are Brjuno numbers for \alpha=0.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:48:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Luzzi",
"Laura",
""
],
[
"Marmi",
"Stefano",
""
],
[
"Nakada",
"Hitoshi",
""
],
[
"Natsui",
"Rie",
""
]
] |
0705.1691 | Ilya Selyuzhenkov Dr. | STAR Collaboration: B.I. Abelev, I. Selyuzhenkov, et al | Global polarization measurement in Au+Au collisions | 11 pages, 10 figures, 1 table, minor changes, accepted for
publication in Phys. Rev. C | Phys.Rev.C76:024915,2007 | 10.1103/PhysRevC.76.024915 | star-05-11-2007 | nucl-ex | null | The system created in non-central relativistic nucleus-nucleus collisions
possesses large orbital angular momentum. Due to spin-orbit coupling, particles
produced in such a system could become globally polarized along the direction
of the system angular momentum. We present the results of Lambda and
anti-Lambda hyperon global polarization measurements in Au+Au collisions at
sqrt{s_NN}=62.4 GeV and 200 GeV performed with the STAR detector at RHIC. The
observed global polarization of Lambda and anti-Lambda hyperons in the STAR
acceptance is consistent with zero within the precision of the measurements.
The obtained upper limit, |P_{Lambda,anti-Lambda}| <= 0.02, is compared to the
theoretical values discussed recently in the literature.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:46:38 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 21:36:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"STAR Collaboration",
"",
""
],
[
"Abelev",
"B. I.",
""
],
[
"Selyuzhenkov",
"I.",
""
]
] |
0705.1692 | Jan Kunes | J. Kunes, V. I. Anisimov, S. L. Skornyakov, A. V. Lukoyanov, and D.
Vollhardt | NiO: Correlated Bandstructure of a Charge-Transfer Insulator | 4 pages, 3 figure | Phys. Rev. Lett. 99, 156404 (2007) | 10.1103/PhysRevLett.99.156404 | null | cond-mat.str-el cond-mat.mtrl-sci | null | The bandstructure of the prototypical charge-transfer insulator NiO is
computed by using a combination of an {\it ab initio} bandstructure method and
the dynamical mean-field theory with a quantum Monte-Carlo impurity solver.
Employing a Hamiltonian which includes both Ni-d and O-p orbitals we find
excellent agreement with the energy bands determined from angle-resolved
photoemission spectroscopy. This solves a long-standing problem in solid state
theory. Most notably we obtain the low-energy Zhang-Rice bands with strongly
k-dependent orbital character discussed previously in the context of low-energy
model theories.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:47:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kunes",
"J.",
""
],
[
"Anisimov",
"V. I.",
""
],
[
"Skornyakov",
"S. L.",
""
],
[
"Lukoyanov",
"A. V.",
""
],
[
"Vollhardt",
"D.",
""
]
] |
0705.1693 | Y. C. Huang (Yong-Chang Huang ) | Yong-Chang Huang, Kai-Hua Yang, Xi-Guo Lee | BRST Invariant Theory Of A Generalized 1+1 Dimensional Nonlinear Sigma
Model With Topological Term | 8 pages | Int.J.Theor.Phys.45:2437-2447,2006 | 10.1007/s10773-006-9209-x | null | hep-th | null | We give a generalized Lagrangian density of 1+1 Dimensional O(3) nonlinear
sigma model with subsidiary constraints, different Lagrange multiplier fields
and topological term, find a lost intrinsic constraint condition, convert the
subsidiary constraints into inner constraints in the nonlinear sigma model,
give the example of not introducing the lost constraint, by comparing the
example with the case of introducing the lost constraint, we obtain that when
not introducing the lost constraint, one has to obtain a lot of various
non-intrinsic constraints. We further deduce the gauge generator, give general
BRST transformation of the model under the general conditions. It is discovered
that there exists a gauge parameter originating from the freedom degree of BRST
transformation in a general O(3) nonlinear sigma model, and we gain the general
commutation relations of ghost field.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:40:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Huang",
"Yong-Chang",
""
],
[
"Yang",
"Kai-Hua",
""
],
[
"Lee",
"Xi-Guo",
""
]
] |
0705.1694 | Yu Zongwen | Su Hu, and Zongwen Yu | Note on Schmidt Decomposition in Infinite Dimensional Hilbert Spaces | This paper has been withdrawn | null | null | null | quant-ph | null | This paper has been withdrawn by the author.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 16:41:18 GMT"
},
{
"version": "v2",
"created": "Fri, 18 May 2007 16:30:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hu",
"Su",
""
],
[
"Yu",
"Zongwen",
""
]
] |
0705.1695 | Claudia Simolo | M. Baldicchi, A. V. Nesterenko, G. M. Prosperi, C. Simolo | QCD coupling below 1 GeV from quarkonium spectrum | Preliminary revision. Typos corrected, comments and references added | Phys.Rev.D77:034013,2008 | 10.1103/PhysRevD.77.034013 | null | hep-ph | null | In this paper we extend the work synthetically presented in Ref.[1] and give
theoretical details and complete tables of numerical results. We exploit
calculations within a Bethe-Salpeter (BS) formalism adjusted for QCD, in order
to extract an ``experimental'' strong coupling \alpha_s^{exp}(Q^2) below 1 GeV
by comparison with the meson spectrum. The BS potential follows from a proper
ansatz on the Wilson loop to encode confinement and is the sum of a
one-gluon-exchange and a confinement terms. Besides, the common perturbative
strong coupling is replaced by the ghost-free expression \alpha_E(Q^2)
according to the prescription of Analytic Perturbation Theory (APT). The
agreement of \alpha_s^{exp}(Q^2) with the APT coupling \alpha_E(Q^2) turns out
to be reasonable from 1 GeV down to the 200 MeV scale, thus confirming
quantitatively the validity of the APT prescription. Below this scale, the
experimental points could give a hint on the vanishing of \alpha_s(Q^2) as Q
approaches zero. This infrared behaviour would be consistent with some lattice
results and a ``massive'' generalization of the APT approach. As a main result,
we claim that the combined BS-APT theoretical scheme provides us with a rather
satisfactory correlated understanding of very high and rather low energy
phenomena from few hundreds MeV to few hundreds GeV.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 17:12:59 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Aug 2007 14:42:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Baldicchi",
"M.",
""
],
[
"Nesterenko",
"A. V.",
""
],
[
"Prosperi",
"G. M.",
""
],
[
"Simolo",
"C.",
""
]
] |
0705.1696 | Charles Epstein | Charles L Epstein | Subelliptic Spin_C Dirac operators, I | To appear in the Annals of Math. 34 pages | null | null | null | math.CV math.AP | null | We consider modifications of the classical dbar-Neumann conditions that
define Fredholm problems for the Spin_C Dirac operator. In part II, we use
boundary layer methods to obtain subelliptic estimates for these boundary value
problems. Using these results, we obtain an expression for the finite part of
the holomorphic Euler characteristic of a strictly pseudoconvex manifold as the
index of a Spin_C-Dirac operator with a subelliptic boundary condition. We also
prove an analogue of the Agranovich-Dynin formula expressing the change in the
index in terms of a relative index on the boundary. If X is a complex manifold
partitioned by a strictly pseudoconvex hypersurface, then we obtain formulae
for the holomorphic Euler characteristic of X as sums of indices of
Spin_C-Dirac operators on the components. This is a subelliptic analogue of
Bojarski's formula in the elliptic case.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 17:16:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Epstein",
"Charles L",
""
]
] |
0705.1697 | Wei Liu | L. W. Chen, C. M. Ko, W. Liu, and M. Nielsen | $D_{sJ}$(2317) meson production at RHIC | 12 pages, 6 figures | Phys.Rev.C76:014906,2007 | 10.1103/PhysRevC.76.014906 | null | nucl-th | null | Production of $D_{sJ}$(2317) mesons in relativistic heavy ion collisions at
RHIC is studied. Using the quark coalescence model, we first determine the
initial number of $D_{sJ}$(2317) mesons produced during hadronization of
created quark-gluon plasma. The predicted $D_{sJ}$(2317) abundance depends
sensitively on the quark structure of the $D_{sJ}$(2317) meson. An
order-of-magnitude larger yield is obtained for a conventional two-quark than
for an exotic four-quark $D_{sJ}$(2317) meson. To include the hadronic effect
on the $D_{sJ}$(2317) meson yield, we have evaluated the absorption cross
sections of the $D_{sJ}$(2317) meson by pion, rho, anti-kaon, and vector
anti-kaon in a phenomenological hadronic model. Taking into consideration the
absorption and production of $D_{sJ}$(2317) mesons during the hadronic stage of
heavy ion collisions via a kinetic model, we find that the final yield of
$D_{sJ}$(2317) mesons remains sensitive to its initial number produced from the
quark-gluon plasma, providing thus the possibility of studying the quark
structure of the $D_{sJ}$(2317) meson and its production mechanism in
relativistic heavy ion collisions.
| [
{
"version": "v1",
"created": "Fri, 11 May 2007 17:17:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chen",
"L. W.",
""
],
[
"Ko",
"C. M.",
""
],
[
"Liu",
"W.",
""
],
[
"Nielsen",
"M.",
""
]
] |
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