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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0708.1049 | Damien Chablat | Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN), F\'elix Majou
(IRCCyN), Jean-Pierre Merlet (INRIA Sophia-Antipolis) | An Interval Analysis Based Study for the Design and the Comparison of
3-DOF Parallel Kinematic Machines | null | International Journal of Robotics Research 23, 6 (2004) 615-624 | null | null | cs.RO | null | This paper addresses an interval analysis based study that is applied to the
design and the comparison of 3-DOF parallel kinematic machines. Two design
criteria are used, (i) a regular workspace shape and, (ii) a kinetostatic
performance index that needs to be as homogeneous as possible throughout the
workspace. The interval analysis based method takes these two criteria into
account: on the basis of prescribed kinetostatic performances, the workspace is
analysed to find out the largest regular dextrous workspace enclosed in the
Cartesian workspace. An algorithm describing this method is introduced. Two
3-DOF translational parallel mechanisms designed for machining applications are
compared using this method. The first machine features three fixed linear
joints which are mounted orthogonally and the second one features three linear
joints which are mounted in parallel. In both cases, the mobile platform moves
in the Cartesian x-y-z space with fixed orientation.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:06:48 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
],
[
"Majou",
"Félix",
"",
"IRCCyN"
],
[
"Merlet",
"Jean-Pierre",
"",
"INRIA Sophia-Antipolis"
]
] |
0708.1050 | Jonathan Arons | Jonathan Arons | Pulsars: Progress, Problems and Prospects | 55 pages, 21 figures. To appear in Springer Lecture Notes on "Neutron
Stars and Pulsars, 40 years after the discovery", ed. W.Becker, 2008 | null | null | null | astro-ph | null | I survey recent successes in the application of relativistic MHD and
force-free electrodynamics to the modeling of the pulsars' rotational energy
loss mechanism as well as to the structure and emission characteristics of
Pulsar Wind Nebulae. I suggest that unsteady reconnection in the current sheet
separating the closed from the open zones of the magnetosphere is responsible
for the torque fluctuations observed in some pulsars, as well as for departures
of the braking index from the canonical value of 3. I emphasize the
significance of the boundary layer between the closed and open zones as the
active site in the outer magnetopshere. I elaborate on the conflict between the
models currently in use to interpret the gamma ray and X-ray pulses from these
systems with the electric current flows found in the spin down models. Because
the polar cap ``gap'' is the essential component in the supply of plasma to
pulsar magnetospheres and to pulsar wind nebulae, I emphasize the importance of
high sensitivity gamma ray observations of pulsars with core components of
radio emission and high magnetospheric voltage, since these observations will
look directly into the polar plasma production region. I also discuss the shock
conversion of flow energy into the spectra of the synchrotron emitting
particles in the Nebulae. I comment on the prospects for future developments
and improvements in all these areas.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:59:17 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Arons",
"Jonathan",
""
]
] |
0708.1051 | Colin Mallows | Colin Mallows | Deconvolution by simulation | Published at http://dx.doi.org/10.1214/074921707000000021 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 1-11 | 10.1214/074921707000000021 | IMS-LNMS54-LNMS5401 | stat.CO | null | Given samples (x_1,...,x_m) and (z_1,...,z_n) which we believe are
independent realizations of random variables X and Z respectively, where we
further believe that Z=X+Y with Y independent of X, the problem is to estimate
the distribution of Y. We present a new method for doing this, involving
simulation. Experiments suggest that the method provides useful estimates.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:15:05 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Mallows",
"Colin",
""
]
] |
0708.1052 | Olindo Corradini | Olindo Corradini and Alberto Iglesias | Trace Anomaly Inflation in Brane Induced Gravity | 15 pages; minor rephrasing of a few sentences (to appear in JCAP) | JCAP0805:012,2008 | 10.1088/1475-7516/2008/05/012 | null | hep-th astro-ph gr-qc | null | In the present letter we find that Starobinsky's inflationary solution is
also valid in the Dvali-Gabadadze-Porrati (DGP) model where a 3-brane is
embedded in 5-dimensional Minkowski bulk. We show that such a solution is
typically not supported by the Self-Accelerated branch of the model, giving
therefore a natural selection of the conventional branch of solutions. In the
absence of brane induced Einstein-Hilbert term the SA branch is always selected
out. We then study the linearized modes around all such de Sitter brane
solutions finding perturbative stability for a range of parameters of the brane
QFT.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:11:07 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Aug 2007 07:47:24 GMT"
},
{
"version": "v3",
"created": "Fri, 22 Feb 2008 09:51:23 GMT"
},
{
"version": "v4",
"created": "Thu, 24 Apr 2008 13:49:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Corradini",
"Olindo",
""
],
[
"Iglesias",
"Alberto",
""
]
] |
0708.1053 | Tansel Ak | T. Ak, S. Bilir, S. Ak, Z. Eker | Spatial distribution and galactic model parameters of cataclysmic
variables | 29 pages, 9 figures and 5 tables, accepted for publication in New
Astronomy | NewAstron.13:133-143,2008 | 10.1016/j.newast.2007.08.003 | null | astro-ph | null | The spatial distribution, galactic model parameters and luminosity function
of cataclysmic variables (CVs) in the solar neighbourhood have been determined
from a carefully established sample of 459 CVs. The sample contains all of the
CVs with distances computed from the Period-Luminosity-Colours (PLCs) relation
of CVs which has been recently derived and calibrated with {\em 2MASS}
photometric data. It has been found that an exponential function fits best to
the observational z-distributions of all of the CVs in the sample, non-magnetic
CVs and dwarf novae, while the sech^{2} function is more appropriate for
nova-like stars and polars. The vertical scaleheight of CVs is 158$\pm$14 pc
for the {\em 2MASS} J-band limiting apparent magnitude of 15.8. On the other
hand, the vertical scaleheights are 128$\pm$20 and 160$\pm$5 pc for dwarf novae
and nova-like stars, respectively. The local space density of CVs is found to
be $\sim3\times10^{-5}$ pc^{-3} which is in agreement with the lower limit of
the theoretical predictions. The luminosity function of CVs shows an increasing
trend toward higher space densities at low luminosities, implying that the
number of short-period systems should be high. The discrepancies between the
theoretical and observational population studies of CVs will almost disappear
if for the z-dependence of the space density the sech^{2} density function is
used.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:23:27 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ak",
"T.",
""
],
[
"Bilir",
"S.",
""
],
[
"Ak",
"S.",
""
],
[
"Eker",
"Z.",
""
]
] |
0708.1054 | Chao A. Hsiung | I-Shou Chang, Li-Chu Chien, Chao A. Hsiung, Chi-Chung Wen, Yuh-Jenn Wu | Shape restricted regression with random Bernstein polynomials | Published at http://dx.doi.org/10.1214/074921707000000157 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 187-202 | 10.1214/074921707000000157 | IMS-LNMS54-LNMS5415 | math.ST stat.TH | null | Shape restricted regressions, including isotonic regression and concave
regression as special cases, are studied using priors on Bernstein polynomials
and Markov chain Monte Carlo methods. These priors have large supports, select
only smooth functions, can easily incorporate geometric information into the
prior, and can be generated without computational difficulty. Algorithms
generating priors and posteriors are proposed, and simulation studies are
conducted to illustrate the performance of this approach. Comparisons with the
density-regression method of Dette et al. (2006) are included.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:32:27 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Chang",
"I-Shou",
""
],
[
"Chien",
"Li-Chu",
""
],
[
"Hsiung",
"Chao A.",
""
],
[
"Wen",
"Chi-Chung",
""
],
[
"Wu",
"Yuh-Jenn",
""
]
] |
0708.1055 | Won-Kee Park | Won-Kee Park and Myung Gyoon Lee | A Catalog of New M33 Star Clusters Based on the HST/WFPC2 Images | 27 pages, 7 figures, and 5 tables. Accepted for publication in AJ | Astron.J.134:2168-2178,2007 | 10.1086/522627 | null | astro-ph | null | We present the result of a survey for star clusters in M33 using the
HST/WFPC2 archive images. We have found 104 star clusters, including 32 new
ones, in the images of 24 fields that were not included in the previous
studies. Combining these with previous data in the literature, we increase the
number of M33 star clusters found in the HST images to 242. We have derived BVI
integrated photometry of these star clusters from the CCD images taken with
CFH12k mosaic camera at CFHT. Integrated color-magnitude diagrams of the M33
star clusters are found to be similar in general to those of star clusters in
the Large Magellanic Cloud, except that M33 has a much lower fraction of blue
star clusters. We find 29 red star clusters with 0.5 <= (B-V)_0 <= 1.1 and 0.7
<=(V-I)_0 <= 1.2, which are old globular cluster candidates. We divide the
cluster sample into three groups according to their (B-V)_0 color: blue star
clusters with (B-V)_0 <= 0.3, intermediate color star clusters with 0.3 <
(B-V)_0 <0.5, and red star clusters with (B-V)_0 >= 0.5. Most of the new
clusters in M33 are located along the sequence that is consistent with the
theoretical evolutionary path for Z=0.004, Y=0.24 in the (B-V)_0--(V-I)_0
diagram, while a few of them are in the redder side in the (V-I)_0 color. The
red clusters are found relatively more in the outer region of M33 than the blue
and intermediate color clusters, and that many of the blue stars are located in
the HII regions. The luminosity function for the blue star clusters shows a
peak at Mv ~ -7.3 mag, while that for the intermediate color star cluster shows
a peak at the fainter magnitude Mv ~ -6.3 mag. The luminosity function for the
red star clusters shows also a peak at Mv ~ -6.8 mag, although the number of
the clusters is small.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:41:51 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Park",
"Won-Kee",
""
],
[
"Lee",
"Myung Gyoon",
""
]
] |
0708.1056 | Karen Michaeli | K. Michaeli and A. M. Finkel'stein | Suppression of Tunneling of Superconducting Vortices Caused by a Remote
Gate: Example of an Extended Object Tunneling | 12 pages, 3 figures | Physical Review B 76, 064506 (2007) | 10.1103/PhysRevB.76.064506 | null | cond-mat.supr-con | null | We discuss a recent experiment in which the resistance of a superconducting
film has been measured in magnetic field. A strong decrease of the
superconducting film resistance has been observed when a metallic gate is
placed above the film. We study how the magnetic coupling between vortices in a
thin superconducting film and electrons in a remote unbiased gate suppresses
the tunneling rate of the vortices. We examine two general approaches to
analyze tunneling in the presence of slow low-energy degrees of freedom: the
functional-integral and scattering formalisms. In the first one, the response
of the electrons inside the metallic gate to a change in the vortex position is
described by the "tunneling with dissipation". We consider the Eddy current
induced in the gate by the magnetic flux of the vortex as a result of
tunneling. In the second approach, the response is given in terms of scattering
of the electrons by the magnetic flux of the vortex in a way similar to the
Aharonov-Bohm scattering. A sudden change in the vortex position leads to the
Orthogonality Catastrophe that opposes the vortex tunneling. We show that the
magnetic coupling between the vortices and the electrons inside the gate can
lead to a dramatic suppression of the vortex tunneling, restoring the
superconducting property in accord with the experiment.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 07:47:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Michaeli",
"K.",
""
],
[
"Finkel'stein",
"A. M.",
""
]
] |
0708.1057 | Bob Holdom | B. Holdom | Dpes massless QCD have vacuum energy? | 8 pages, no figures, version to appear in NJP | NewJ.Phys.10:053040,2008 | 10.1088/1367-2630/10/5/053040 | null | hep-ph hep-th | null | It is widely thought that this question has a positive answer, but we argue
that the support for this belief from both experiment and theory is weak or
nonexistent. We then list some of the ramifications of a negative answer.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:43:30 GMT"
},
{
"version": "v2",
"created": "Wed, 14 May 2008 02:40:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Holdom",
"B.",
""
]
] |
0708.1058 | Zhiliang Ying | Irene Gijbels, Danyu Lin, Zhiliang Ying | Non- and semi-parametric analysis of failure time data with missing
failure indicators | Published at http://dx.doi.org/10.1214/074921707000000166 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 203-223 | 10.1214/074921707000000166 | IMS-LNMS54-LNMS5416 | math.ST stat.TH | null | A class of estimating functions is introduced for the regression parameter of
the Cox proportional hazards model to allow unknown failure statuses on some
study subjects. The consistency and asymptotic normality of the resulting
estimators are established under mild conditions. An adaptive estimator which
achieves the minimum variance-covariance bound of the class is constructed.
Numerical studies demonstrate that the asymptotic approximations are adequate
for practical use and that the efficiency gain of the adaptive estimator over
the complete-case analysis can be quite substantial. Similar methods are also
developed for the nonparametric estimation of the survival function of a
homogeneous population and for the estimation of the cumulative baseline hazard
function under the Cox model.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 08:18:20 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Gijbels",
"Irene",
""
],
[
"Lin",
"Danyu",
""
],
[
"Ying",
"Zhiliang",
""
]
] |
0708.1059 | Edwin J. Son | Wontae Kim, Edwin J. Son | Two non-commutative parameters and regular cosmological phase transition
in the semi-classical dilaton cosmology | 13 pages, 4 figures; v2. to appear in Mod. Phys. Lett. A | Mod.Phys.Lett.A23:1079-1091,2008 | 10.1142/S0217732308027047 | null | gr-qc | null | We study cosmological phase transitions from modified equations of motion by
introducing two non-commutative parameters in the Poisson brackets, which
describes the initial- and future-singularity-free phase transition in the
soluble semi-classical dilaton gravity with a non-vanishing cosmological
constant. Accelerated expansion and decelerated expansion corresponding to the
FRW phase appear alternatively, and then it ends up with the second accelerated
expansion. The final stage of the universe approaches the flat spacetime
independent of the initial state of the curvature scalar as long as the product
of the two non-commutative parameters is less than one. Finally, we show that
the initial-singularity-free condition is related to the second accelerated
expansion of the universe.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 08:34:52 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Apr 2008 05:29:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kim",
"Wontae",
""
],
[
"Son",
"Edwin J.",
""
]
] |
0708.1060 | Johan Mauritsson | J. Mauritsson, P. Johnsson, E. Gustafsson, M. Swoboda, T. Ruchon, A.
LHuillier and K. J. Schafer | Coherent Electron Scattering Captured by an Attosecond Quantum
Stroboscope | 6 pages, 4 figures | Phys. Rev. Lett. 100, 073003 (2008) | 10.1103/PhysRevLett.100.073003 | null | physics.atom-ph | null | The basic properties of atoms, molecules and solids are governed by electron
dynamics which take place on extremely short time scales. To measure and
control these dynamics therefore requires ultrafast sources of radiation
combined with efficient detection techniques. The generation of extreme
ultraviolet (XUV) attosecond (1 as = 10-18 s) pulses has, for the first time,
made direct measurements of electron dynamics possible. Nevertheless, while
various applications of attosecond pulses have been demonstrated
experimentally, no one has yet captured or controlled the full three
dimensional motion of an electron on an attosecond time scale. Here we
demonstrate an attosecond quantum stroboscope capable of guiding and imaging
electron motion on a sub-femtosecond (1 fs = 10-15 s) time scale. It is based
on a sequence of identical attosecond pulses which are synchronized with a
guiding laser field. The pulse to pulse separation in the train is tailored to
exactly match an optical cycle of the laser field and the electron momentum
distributions are detected with a velocity map imaging spectrometer (VMIS).
This technique has enabled us to guide ionized electrons back to their parent
ion and image the scattering event. We envision that coherent electron
scattering from atoms, molecules and surfaces captured by the attosecond
quantum stroboscope will complement more traditional scattering techniques
since it provides high temporal as well as spatial resolution.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 08:40:34 GMT"
}
] | 2008-02-27T00:00:00 | [
[
"Mauritsson",
"J.",
""
],
[
"Johnsson",
"P.",
""
],
[
"Gustafsson",
"E.",
""
],
[
"Swoboda",
"M.",
""
],
[
"Ruchon",
"T.",
""
],
[
"LHuillier",
"A.",
""
],
[
"Schafer",
"K. J.",
""
]
] |
0708.1061 | Micha Mandel | Micha Mandel | Nonparametric estimation of a distribution function under biased
sampling and censoring | Published at http://dx.doi.org/10.1214/074921707000000175 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 224-238 | 10.1214/074921707000000175 | IMS-LNMS54-LNMS5417 | math.ST stat.TH | null | This paper derives the nonparametric maximum likelihood estimator (NPMLE) of
a distribution function from observations which are subject to both bias and
censoring. The NPMLE is obtained by a simple EM algorithm which is an extension
of the algorithm suggested by Vardi (Biometrika, 1989) for size biased data.
Application of the algorithm to many models is discussed and a simulation study
compares the estimator's performance to that of the product-limit estimator
(PLE). An example demonstrates the utility of the NPMLE to data where the PLE
is inappropriate.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 08:52:33 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Mandel",
"Micha",
""
]
] |
0708.1062 | Oded Zilberberg | Oded Zilberberg, Bernd Braunecker, Daniel Loss | Controlled-NOT for multiparticle qubits and topological quantum
computation based on parity measurements | 8 pages, 6 figures, updated references | Phys. Rev. A 77, 012327 (2008) | 10.1103/PhysRevA.77.012327 | null | cond-mat.mes-hall quant-ph | null | We discuss a measurement-based implementation of a controlled-NOT (CNOT)
quantum gate. Such a gate has recently been discussed for free electron qubits.
Here we extend this scheme for qubits encoded in product states of two (or
more) spins-1/2 or in equivalent systems. The key to such an extension is to
find a feasible qubit-parity meter. We present a general scheme for reducing
this qubit-parity meter to a local spin-parity measurement performed on two
spins, one from each qubit. Two possible realizations of a multiparticle CNOT
gate are further discussed: electron spins in double quantum dots in the
singlet-triplet encoding, and nu=5/2 Ising non-Abelian anyons using topological
quantum computation braiding operations and nontopological charge measurements.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 08:54:02 GMT"
},
{
"version": "v2",
"created": "Fri, 25 Jan 2008 13:01:45 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Zilberberg",
"Oded",
""
],
[
"Braunecker",
"Bernd",
""
],
[
"Loss",
"Daniel",
""
]
] |
0708.1063 | Michael E. Flatt\'e | B. L. Sheu, R. C. Myers, J.-M. Tang, N. Samarth, D. D. Awschalom, P.
Schiffer, M. E. Flatt\'e | Onset of ferromagnetism in low-doped GaMnAs | 5 pages, 4 figures | Phys. Rev. Lett. 99, 227205 (2007) | 10.1103/PhysRevLett.99.227205 | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | We develop a quantitatively predictive theory for impurity-band
ferromagnetism in the low-doping regime of GaMnAs and compare with experimental
measurements of a series of samples whose compositions span the transition from
paramagnetic insulating to ferromagnetic conducting behavior. The theoretical
Curie temperatures depend sensitively on the local fluctuations in the Mn-hole
binding energy, which originates from disorder in the Mn distribution as well
as the presence of As antisite defects. The experimentally-determined hopping
energy at the Curie temperature is roughly constant over a series of samples
whose conductivities vary more than 10^4 and whose hole concentrations vary
more than 10^2. Thus in this regime the hopping energy is an excellent
predictor of the Curie temperature for a sample, in agreement with the theory.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:10:51 GMT"
}
] | 2008-07-31T00:00:00 | [
[
"Sheu",
"B. L.",
""
],
[
"Myers",
"R. C.",
""
],
[
"Tang",
"J. -M.",
""
],
[
"Samarth",
"N.",
""
],
[
"Awschalom",
"D. D.",
""
],
[
"Schiffer",
"P.",
""
],
[
"Flatté",
"M. E.",
""
]
] |
0708.1064 | Jayanta Kumar Pal | Jayanta Kumar Pal, Michael Woodroofe, Mary Meyer | Estimating a Polya frequency function_2 | Published at http://dx.doi.org/10.1214/074921707000000184 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 239-249 | 10.1214/074921707000000184 | IMS-LNMS54-LNMS5418 | math.ST stat.TH | null | We consider the non-parametric maximum likelihood estimation in the class of
Polya frequency functions of order two, viz. the densities with a concave
logarithm. This is a subclass of unimodal densities and fairly rich in general.
The NPMLE is shown to be the solution to a convex programming problem in the
Euclidean space and an algorithm is devised similar to the iterative convex
minorant algorithm by Jongbleod (1999). The estimator achieves Hellinger
consistency when the true density is a PFF_2 itself.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:14:16 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Pal",
"Jayanta Kumar",
""
],
[
"Woodroofe",
"Michael",
""
],
[
"Meyer",
"Mary",
""
]
] |
0708.1065 | Hideo Mitsuhashi | Hideo Mitsuhashi | A super Frobenius formula for the characters of Iwahori-Hecke algebras | 23 pages | null | null | null | math.RT math.QA | null | We establish a super Frobenius formula for the characters of Iwahori-Hecke
algebras. We show that the Hall-Littlewood sypersymmetric function, up to
constant, generates the values of the irreducible characters of Iwahori-Hecke
algebras at the elements corresponding to cycle permutations. Our formula in
this article includes both the ordinary quantum case and the classical super
case.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:41:38 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Mitsuhashi",
"Hideo",
""
]
] |
0708.1066 | Akihiko Fukui | A. Fukui, F. Abe, K. Ayani, M. Fujii, R. Iizuka, Y. Itow, K. Kabumoto,
K. Kamiya, T. Kawabata, S. Kawanomoto, K. Kinugasa, R. A. Koff, T. Krajci, H.
Naito, D. Nogami, S. Narusawa, N. Ohishi, K. Ohnishi, T. Sumi, F. Tsumuraya | Observation of the first gravitational microlensing event in a sparse
stellar field : the Tago event | 13 pages, 2 tables, 3 figures, accepted by ApJ | 2007ApJ...670..423F | 10.1086/522296 | null | astro-ph | null | We report the observation of the first gravitational microlensing event in a
sparse stellar field, involving the brightest (V=11.4 mag) andclosest (~ 1 kpc)
source star to date. This event was discovered by an amateurastronomer, A.
Tago, on 2006 October 31 as a transient brightening, by ~4.5 mag during a ~15
day period, of a normal A-type star (GSC 3656-1328) in the Cassiopeia
constellation. Analysis of both spectroscopic observations and the light curve
indicates that this event was caused by gravitational microlensing rather than
an intrinsically variable star. Discovery of this single event over a 30 year
period is roughly consistent with the expected microlensing rate for the whole
sky down to V = 12 mag stars. However, the probability for finding events with
such a high magnification (~ 50) is much smaller, by a factor ~1/50, which
implies that the true event rate may be higher than expected. This discovery
indicates the potential of all sky variability surveys, employing frequent
sampling by telescopes with small apertures and wide fields of view, for
finding such rare transient events, and using the observations to explore
galactic disk structure and search for exo-planets.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:23:21 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 08:33:58 GMT"
},
{
"version": "v3",
"created": "Wed, 9 Jan 2008 02:52:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fukui",
"A.",
""
],
[
"Abe",
"F.",
""
],
[
"Ayani",
"K.",
""
],
[
"Fujii",
"M.",
""
],
[
"Iizuka",
"R.",
""
],
[
"Itow",
"Y.",
""
],
[
"Kabumoto",
"K.",
""
],
[
"Kamiya",
"K.",
""
],
[
"Kawabata",
"T.",
""
],
[
"Kawanomoto",
"S.",
""
],
[
"Kinugasa",
"K.",
""
],
[
"Koff",
"R. A.",
""
],
[
"Krajci",
"T.",
""
],
[
"Naito",
"H.",
""
],
[
"Nogami",
"D.",
""
],
[
"Narusawa",
"S.",
""
],
[
"Ohishi",
"N.",
""
],
[
"Ohnishi",
"K.",
""
],
[
"Sumi",
"T.",
""
],
[
"Tsumuraya",
"F.",
""
]
] |
0708.1067 | Debashish Chowdhury | Tripti Tripathi and Debashish Chowdhury | Interacting RNA polymerase motors on DNA track: effects of traffic
congestion and intrinsic noise on RNA synthesis | 13 pages, including 6 EPS figures; accepted for publication in
Physical Review E | Physical Review E 77, 011921 (2008) | 10.1103/PhysRevE.77.011921 | null | physics.bio-ph q-bio.BM | null | RNA polymerase (RNAP) is an enzyme that synthesizes a messenger RNA (mRNA)
strand which is complementary to a single-stranded DNA template. From the
perspective of physicists, an RNAP is a molecular motor that utilizes chemical
energy input to move along the track formed by a DNA. In many circumstances,
which are described in this paper, a large number of RNAPs move simultaneously
along the same track; we refer to such collective movements of the RNAPs as
RNAP traffic. Here we develop a theoretical model for RNAP traffic by
incorporating the steric interactions between RNAPs as well as the
mechano-chemical cycle of individual RNAPs during the elongation of the mRNA.
By a combination of analytical and numerical techniques, we calculate the rates
of mRNA synthesis and the average density profile of the RNAPs on the DNA
track. We also introduce, and compute, two new measures of fluctuations in the
synthesis of RNA. Analyzing these fluctuations, we show how the level of {\it
intrinsic noise} in mRNA synthesis depends on the concentrations of the RNAPs
as well as on those of some of the reactants and the products of the enzymatic
reactions catalyzed by RNAP. We suggest appropriate experimental systems and
techniques for testing our theoretical predictions.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:31:11 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Aug 2007 09:59:27 GMT"
},
{
"version": "v3",
"created": "Thu, 10 Jan 2008 15:06:53 GMT"
}
] | 2008-02-06T00:00:00 | [
[
"Tripathi",
"Tripti",
""
],
[
"Chowdhury",
"Debashish",
""
]
] |
0708.1068 | Shao-Hsuan Chiu | Shao-Hsuan Chiu | Capability of multi-detector analyses on supernova neutrinos | This paper has been withdrawn | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper has been withdrawn by the author, due to errors in the figures.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:31:13 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Nov 2007 07:12:06 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jul 2008 01:16:01 GMT"
},
{
"version": "v4",
"created": "Tue, 16 Mar 2010 07:08:13 GMT"
}
] | 2010-03-17T00:00:00 | [
[
"Chiu",
"Shao-Hsuan",
""
]
] |
0708.1069 | John E. Kolassa | Juan Zhang, John E. Kolassa | A comparison of the accuracy of saddlepoint conditional cumulative
distribution function approximations | Published at http://dx.doi.org/10.1214/074921707000000193 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 250-259 | 10.1214/074921707000000193 | IMS-LNMS54-LNMS5419 | stat.ME | null | Consider a model parameterized by a scalar parameter of interest and a
nuisance parameter vector. Inference about the parameter of interest may be
based on the signed root of the likelihood ratio statistic R. The standard
normal approximation to the conditional distribution of R typically has error
of order O(n^{-1/2}), where n is the sample size. There are several
modifications for R, which reduce the order of error in the approximations. In
this paper, we mainly investigate Barndorff-Nielsen's modified directed
likelihood ratio statistic, Severini's empirical adjustment, and DiCiccio and
Martin's two modifications, involving the Bayesian approach and the conditional
likelihood ratio statistic. For each modification, two formats were employed to
approximate the conditional cumulative distribution function; these are
Barndorff-Nielson formats and the Lugannani and Rice formats. All
approximations were applied to inference on the ratio of means for two
independent exponential random variables. We constructed one and two-sided
hypotheses tests and used the actual sizes of the tests as the measurements of
accuracy to compare those approximations.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:31:47 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Zhang",
"Juan",
""
],
[
"Kolassa",
"John E.",
""
]
] |
0708.1070 | Richard A. Vitale | Richard A. Vitale | Multivariate medians and measure-symmetrization | Published at http://dx.doi.org/10.1214/074921707000000201 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 260-267 | 10.1214/074921707000000201 | IMS-LNMS54-LNMS5420 | math.ST stat.TH | null | We discuss two research areas dealing respectively with (1) a class of
multivariate medians and (2) a symmetrization algorithm for probability
measures.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:43:52 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Vitale",
"Richard A.",
""
]
] |
0708.1071 | Larry Shepp | Larry Shepp | Statistical thinking: From Tukey to Vardi and beyond | Published at http://dx.doi.org/10.1214/074921707000000210 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 268-273 | 10.1214/074921707000000210 | IMS-LNMS54-LNMS5421 | math.ST stat.TH | null | Data miners (minors?) and neural networkers tend to eschew modelling, misled
perhaps by misinterpretation of strongly expressed views of John Tukey. I
discuss Vardi's views of these issues as well as other aspects of Vardi's work
in emision tomography and in sampling bias.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:52:03 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Shepp",
"Larry",
""
]
] |
0708.1072 | Anjan Ananda Sen | A.A. Sen | Deviation from $\Lambda$CDM: Pressure Parametrization | 5 pages, 2 eps figure, the title has been changed, also some minor
discussions included without changing the conclusions, Accepted in Physical
Review D | Phys.Rev.D77:043508,2008 | 10.1103/PhysRevD.77.043508 | null | astro-ph gr-qc hep-ph | null | Most parametrizations for dark energy involve the equation of state $w$ of
the dark energy. In this work, we choose the pressure of the dark energy to
parametrize. As $p = constant$ essentially gives a cosmological constant, we
use the Taylor expansion around this behavior $p = -p_{0} + (1-a)p_{1} + ....$
to study the small deviations from the cosmological constant. In our model, the
departure from the cosmological constant behavior has been modeled by the
presence of extra K-essence fields while keeping the cosmological constant term
untouched. The model is similar to assisted inflation scenario in a sense that
for any higher order deviation in terms of Taylor series expansion, one needs
multiple K-essence fields. We have also tested our model with the recent
observational data coming from Supernova type Ia measurements, the baryon
oscillations peak (BAO) and the gas mass fraction of the galaxy clusters
inferred from X-ray observations and obtain constraints for our model
parameters.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:03:44 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jan 2008 04:57:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sen",
"A. A.",
""
]
] |
0708.1073 | Simone Scotti | Simone Scotti | Errors Theory using Dirichlet Forms, Linear Partial Differential
Equations and Wavelets | 17 pages, some misprints corrected | null | null | null | math.AP math.PR | null | We present an application of error theory using Dirichlet Forms in linear
partial differential equations (LPDE). We study the transmission of an
uncertainty on the terminal condition to the solution of the LPDE thanks to the
decomposition of the solution on a wavelets basis. We analyze the basic
properties and a particular class of LPDE where the wavelets bases show their
powerful, the combination of error theory and wavelets basis justifies some
hypotheses, helpful to simplify the computation.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 09:59:58 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Sep 2007 08:44:28 GMT"
}
] | 2007-09-18T00:00:00 | [
[
"Scotti",
"Simone",
""
]
] |
0708.1074 | I. A. Fomin | E.V. Surovtsev, I.A. Fomin | Model calculation of orientational effect of deformed aerogel on the
order parameter of superfluid 3He | Contribution to QFS 2007, 6 pages, 1 figure | null | 10.1007/s10909-007-9578-4 | null | cond-mat.dis-nn cond-mat.mes-hall | null | Theory of Rainer and Vuorio of small objects in superfluid ^3He is applied
for calculation of the average orientational effect of a deformed aerogel on
the order parameter of 3He. The minimum deformation which stabilizes the
ordered state is evaluated both for specular and diffusive scattering of
quasiparticles by the threads of aerogel.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:09:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Surovtsev",
"E. V.",
""
],
[
"Fomin",
"I. A.",
""
]
] |
0708.1075 | Olaf Lechtenfeld | Anton Galajinsky, Olaf Lechtenfeld, Kirill Polovnikov | N=4 superconformal Calogero models | 1+21 pages; v2: slight changes in section 4, new subsection 5.3 with
additional results (a full list of n=3 and n=4 models), acknowledgments and
one reference added, JHEP version | JHEP0711:008,2007 | 10.1088/1126-6708/2007/11/008 | null | hep-th | null | We continue the research initiated in hep-th/0607215 and apply our method of
conformal automorphisms to generate various N=4 superconformal quantum
many-body systems on the real line from a set of decoupled particles extended
by fermionic degrees of freedom. The su(1,1|2) invariant models are governed by
two scalar potentials obeying a system of nonlinear partial differential
equations which generalizes the Witten-Dijkgraaf-Verlinde-Verlinde equations.
As an application, the N=4 superconformal extension of the three-particle
(A-type) Calogero model generates a unique G_2-type Hamiltonian featuring
three-body interactions. We fully analyze the N=4 superconformal three- and
four-particle models based on the root systems of A_1 + G_2 and F_4,
respectively. Beyond Wyllard's solutions we find a list of new models, whose
translational non-invariance of the center-of-mass motion fails to decouple and
extends even to the relative particle motion.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:23:42 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 10:33:42 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Galajinsky",
"Anton",
""
],
[
"Lechtenfeld",
"Olaf",
""
],
[
"Polovnikov",
"Kirill",
""
]
] |
0708.1076 | Wojciech Florkowski | A. Bialas, M. Chojnacki, W. Florkowski | Early evolution of transversally thermalized partons | shorter version accepted by Physics Letters B | Phys.Lett.B661:325-329,2008 | 10.1016/j.physletb.2008.02.042 | null | nucl-th hep-ph nucl-ex | null | The idea that the parton system created in relativistic heavy-ion collisions
(i) emerges in a state with transverse momenta close to thermodynamic
equilibrium and (ii) its evolution at early times is dominated by the
2-dimensional (transverse) hydrodynamics of the ideal fluid is investigated. It
is argued that this mechanism may help to solve the problem of early
equilibration.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:22:30 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Apr 2008 10:01:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bialas",
"A.",
""
],
[
"Chojnacki",
"M.",
""
],
[
"Florkowski",
"W.",
""
]
] |
0708.1077 | Satoshi Nagaoka | Yoshihisa Kitazawa and Satoshi Nagaoka | Green-Schwarz superstring from type IIB matrix model | 5 pages, 3 figures, minor revisions | Phys.Rev.D77:026009,2008 | 10.1103/PhysRevD.77.026009 | KEK-TH-1168 | hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct Green-Schwarz (GS) light-cone closed superstring theory from
type IIB matrix model. A GS light-cone string action is derived from two
dimensional N=8 U(n) noncommutative Yang-Mills (NCYM) by identifying
noncommutative scale with string scale. Supersymmetry transformation for the
light-cone gauge action is also derived from supersymmetry transformation for
IIB matrix model. By identifying the physical states and interaction vertices,
string theory is perturbatively reproduced.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:44:37 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Apr 2009 07:01:05 GMT"
}
] | 2009-04-01T00:00:00 | [
[
"Kitazawa",
"Yoshihisa",
""
],
[
"Nagaoka",
"Satoshi",
""
]
] |
0708.1078 | Jianwen Zhang | Marc A. Armand, Jianwen Zhang | Nearly MDS expander codes with reduced alphabet size | null | null | null | null | cs.IT math.IT | null | Recently, Roth and Skachek proposed two methods for constructing nearly
maximum-distance separable (MDS) expander codes. We show that through the
simple modification of using mixed-alphabet codes derived from MDS codes as
constituent codes in their code designs, one can obtain nearly MDS codes of
significantly smaller alphabet size, albeit at the expense of a (very slight)
reduction in code rate.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:45:51 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Armand",
"Marc A.",
""
],
[
"Zhang",
"Jianwen",
""
]
] |
0708.1079 | George Michailidis | Earl Lawrence, George Michailidis, Vijayan N. Nair | Statistical inverse problems in active network tomography | Published at http://dx.doi.org/10.1214/074921707000000049 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 24-44 | 10.1214/074921707000000049 | IMS-LNMS54-LNMS5403 | stat.ME | null | The analysis of computer and communication networks gives rise to some
interesting inverse problems. This paper is concerned with active network
tomography where the goal is to recover information about quality-of-service
(QoS) parameters at the link level from aggregate data measured on end-to-end
network paths. The estimation and monitoring of QoS parameters, such as loss
rates and delays, are of considerable interest to network engineers and
Internet service providers. The paper provides a review of the inverse problems
and recent research on inference for loss rates and delay distributions. Some
new results on parametric inference for delay distributions are also developed.
In addition, a real application on Internet telephony is discussed.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:56:24 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Lawrence",
"Earl",
""
],
[
"Michailidis",
"George",
""
],
[
"Nair",
"Vijayan N.",
""
]
] |
0708.1080 | Lorenzo Iorio | Lorenzo Iorio | Constraints on the range lambda of Yukawa-like modifications to the
Newtonian inverse-square law of gravitation from Solar System planetary
motions | LaTex2e, 1 table, 1 figure, 12 pages. Small change after eq.(10),
pag.6. Final version to appear in JHEP (Journal of High Energy Physics) | JHEP0710:041,2007 | 10.1088/1126-6708/2007/10/041 | null | gr-qc astro-ph hep-ph physics.space-ph | null | In this paper we use the latest corrections to the Newton-Einstein secular
perihelion rates of some planets of the Solar System, phenomenologically
estimated with the EPM2004 ephemerides by the Russian astronomer E.V. Pitjeva,
to put severe constraints on the range parameter lambda characterizing the
Yukawa-like modifications of the Newtonian inverse-square law of gravitation.
It turns out that the range cannot exceed about one tenth of an Astronomical
Unit. We assumed neither equivalence principle violating effects nor spatial
variations of $\alpha$ and $\lambda$. This finding may have important
consequences on all the modified theories of gravity involving Yukawa-type
terms with range parameters much larger than the Solar System size. However,
caution is advised since we, currently have at our disposal only the periehlion
extra-rates estimated by Pitjeva: if and when other groups will estimate their
own corrections to the secular motion of perihelia, more robust and firm tests
may be conducted.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:30:09 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 17:34:44 GMT"
},
{
"version": "v3",
"created": "Sat, 18 Aug 2007 14:14:39 GMT"
},
{
"version": "v4",
"created": "Thu, 20 Sep 2007 11:23:46 GMT"
},
{
"version": "v5",
"created": "Tue, 25 Sep 2007 14:40:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Iorio",
"Lorenzo",
""
]
] |
0708.1081 | Kambiz Fathi | Kambiz Fathi, Silvia Toonen, Jes\'us Falc\'on-Barroso, John E.
Beckman, Olivier Hernandez, Olivier Daigle, Claude Carignan, Tim de Zeeuw | Quantifying Resonant Structure in NGC 6946 from Two-dimensional
Kinematics | Accepted for publication in ApJ Letters | null | 10.1086/522204 | null | astro-ph | null | We study the two-dimensional kinematics of the H-alpha-emitting gas in the
nearby barred Scd galaxy, NGC 6946, in order to determine the pattern speed of
the primary m=2 perturbation mode. The pattern speed is a crucial parameter for
constraining the internal dynamics, estimating the impact velocities of the
gravitational perturbation at the resonance radii, and to set up an
evolutionary scenario for NGC 6946. Our data allows us to derive the best
fitting kinematic position angle and the geometry of the underlying gaseous
disk, which we use to derive the pattern speed using the Tremaine-Weinberg
method. We find a main pattern speed Omega_p=22 km/s/kpc, but our data clearly
reveal the presence of an additional pattern speed Omega_p=47 km/s/kpc in a
zone within 1.25 kpc of the nucleus. Using the epicyclic approximation, we
deduce the location of the resonance radii and confirm that inside the outer
Inner Lindblad Resonance radius of the main oval, a primary bar has formed
rotating at more than twice the outer pattern speed. We further confirm that a
nuclear bar has formed inside the Inner Lindblad Resonance radius of the
primary bar, coinciding with the inner Inner Lindblad Resonance radius of the
large-scale m=2 mode oval.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 10:59:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fathi",
"Kambiz",
""
],
[
"Toonen",
"Silvia",
""
],
[
"Falcón-Barroso",
"Jesús",
""
],
[
"Beckman",
"John E.",
""
],
[
"Hernandez",
"Olivier",
""
],
[
"Daigle",
"Olivier",
""
],
[
"Carignan",
"Claude",
""
],
[
"de Zeeuw",
"Tim",
""
]
] |
0708.1082 | Victor Vakulik | V. G. Vakulik (1), R. E. Schild (2), G. V. Smirnov (1), V. N. Dudinov
(1), and V. S. Tsvetkova (3) ((1) Institute of Astronomy of Kharkov National
University, Ukraine, (2) Center for Astrophysics, Cambridge, U.S.A., (3)
Institute of Radio Astronomy of Nat.Ac.Sci. of Ukraine, Kharkov) | Q2237+0305 source structure and dimensions from light curves simulation | 7 pages, 4 figures, LaTeX | null | 10.1111/j.1365-2966.2007.12422.x | null | astro-ph | null | Assuming a two-component quasar structure model consisting of a central
compact source and an extended outer feature, we produce microlensing
simulations for a population of star-like objects in the lens galaxy. Such a
model is a simplified version of that adopted to explain the brightness
variations observed in Q0957 (Schild & Vakulik 2003). The microlensing light
curves generated for a range of source parameters were compared to the light
curves obtained in the framework of the OGLE program. With a large number of
trials we built, in the domain of the source structure parameters, probability
distributions to find "good" realizations of light curves. The values of the
source parameters which provide the maximum of the joint probability
distribution calculated for all the image components, have been accepted as
estimates for the source structure parameters. The results favour the
two-component model of the quasar brightness structure over a single compact
central source model, and in general the simulations confirm the Schild-Vakulik
model that previously described successfully the microlensing and other
properties of Q0957. Adopting 3300 km/s for the transverse velocity of the
source, the effective size of the central source was determined to be about
2x10^15 cm, and Epsilon =2 was obtained for the ratio of the integral
luminosity of the outer feature to that of the central source.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:24:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vakulik",
"V. G.",
""
],
[
"Schild",
"R. E.",
""
],
[
"Smirnov",
"G. V.",
""
],
[
"Dudinov",
"V. N.",
""
],
[
"Tsvetkova",
"V. S.",
""
]
] |
0708.1083 | Hermine Landt | Hermine Landt (1), Misty C. Bentz (2), Martin J. Ward (3), Martin
Elvis (1), Bradley M. Peterson (2), Kirk T. Korista (4), and Margarita
Karovska (1) ((1) Harvard-Smithsonian CfA, (2) The Ohio State University, (3)
University of Durham, (4) Western Michigan University) | The Near-Infrared Broad Emission Line Region of Active Galactic Nuclei
-- I. The Observations | 45 pages, 17 figures, accepted by ApJS | null | 10.1086/522373 | null | astro-ph | null | We present high quality (high signal-to-noise ratio and moderate spectral
resolution) near-infrared (near-IR) spectroscopic observations of 23 well-known
broad-emission line active galactic nuclei (AGN). Additionally, we obtained
simultaneous (within two months) optical spectroscopy of similar quality. The
near-IR broad emission line spectrum of AGN is dominated by permitted
transitions of hydrogen, helium, oxygen, and calcium, and by the rich spectrum
of singly-ionized iron. In this paper we present the spectra, line
identifications and measurements, and address briefly some of the important
issues regarding the physics of AGN broad emission line regions. In particular,
we investigate the excitation mechanism of neutral oxygen and confront for the
first time theoretical predictions of the near-IR iron emission spectrum with
observations.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:35:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Landt",
"Hermine",
""
],
[
"Bentz",
"Misty C.",
""
],
[
"Ward",
"Martin J.",
""
],
[
"Elvis",
"Martin",
""
],
[
"Peterson",
"Bradley M.",
""
],
[
"Korista",
"Kirk T.",
""
],
[
"Karovska",
"Margarita",
""
]
] |
0708.1084 | Enrico Priola | Enrico Priola and Jerzy Zabczyk | Densities for Ornstein-Uhlenbeck processes with jumps | null | null | 10.1112/blms/bdn099 | null | math.PR math.AP | null | We consider an Ornstein-Uhlenbeck process with values in R^n driven by a
L\'evy process (Z_t) taking values in R^d with d possibly smaller than n. The
L\'evy noise can have a degenerate or even vanishing Gaussian component.
Under a controllability condition and an assumption on the L\'evy measure of
(Z_t), we prove that the law of the Ornstein-Uhlenbeck process at any time t>0
has a density on R^n. Moreover, when the L\'evy process is of $\alpha$-stable
type, $\alpha \in (0,2)$, we show that such density is a $C^{\infty}$-function.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:38:18 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Apr 2008 10:26:40 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Priola",
"Enrico",
""
],
[
"Zabczyk",
"Jerzy",
""
]
] |
0708.1085 | J. M. Landwehr | A. Adhikari, L. Denby, J. M. Landwehr, J. Meloche | Using data network metrics, graphics, and topology to explore network
characteristics | Published at http://dx.doi.org/10.1214/074921707000000058 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 62-75 | 10.1214/074921707000000058 | IMS-LNMS54-LNMS5405 | stat.ME | null | Yehuda Vardi introduced the term network tomography and was the first to
propose and study how statistical inverse methods could be adapted to attack
important network problems (Vardi, 1996). More recently, in one of his final
papers, Vardi proposed notions of metrics on networks to define and measure
distances between a network's links, its paths, and also between different
networks (Vardi, 2004). In this paper, we apply Vardi's general approach for
network metrics to a real data network by using data obtained from special data
network tools and testing procedures presented here. We illustrate how the
metrics help explicate interesting features of the traffic characteristics on
the network. We also adapt the metrics in order to condition on traffic passing
through a portion of the network, such as a router or pair of routers, and show
further how this approach helps to discover and explain interesting network
characteristics.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:43:13 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Adhikari",
"A.",
""
],
[
"Denby",
"L.",
""
],
[
"Landwehr",
"J. M.",
""
],
[
"Meloche",
"J.",
""
]
] |
0708.1086 | Peter Rap\v{c}an | Peter Rapcan, John Calsamiglia, Ramon Munoz-Tapia, Emilio Bagan and
Vladimir Buzek | Recycling of quantum information: Multiple observations of quantum
systems | 4 pages | Phys. Scripta T 140, 014059 (2010) | 10.1088/0031-8949/2010/T140/014059 | null | quant-ph | null | Given a finite number of copies of an unknown qubit state that have already
been measured optimally, can one still extract any information about the
original unknown state? We give a positive answer to this question and quantify
the information obtainable by a given observer as a function of the number of
copies in the ensemble, and of the number of independent observers that, one
after the other, have independently measured the same ensemble of qubits before
him. The optimality of the protocol is proven and extensions to other states
and encodings are also studied. According to the general lore, the state after
a measurement has no information about the state before the measurement. Our
results manifestly show that this statement has to be taken with a grain of
salt, specially in situations where the quantum states encode confidential
information.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:11:59 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Rapcan",
"Peter",
""
],
[
"Calsamiglia",
"John",
""
],
[
"Munoz-Tapia",
"Ramon",
""
],
[
"Bagan",
"Emilio",
""
],
[
"Buzek",
"Vladimir",
""
]
] |
0708.1087 | Sebastian Baader | S. Baader, K. Cieliebak, T. Vogel | Legendrian ribbons in overtwisted contact structures | 6 pages, 3 figures | null | null | null | math.GT | null | We show that a null-homologous transverse knot K in the complement of an
overtwisted disk in a contact 3-manifold is the boundary of a Legendrian ribbon
if and only if it possesses a Seifert surface S such that the self-linking
number of K with respect to S satisfies $\sel(K,S)=-\chi(S)$. In particular,
every null-homologous topological knot type in an overtwisted contact manifold
can be represented by the boundary of a Legendrian ribbon. Finally, we show
that a contact structure is tight if and only if every Legendrian ribbon
minimizes genus in its relative homology class.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:25:50 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Baader",
"S.",
""
],
[
"Cieliebak",
"K.",
""
],
[
"Vogel",
"T.",
""
]
] |
0708.1088 | Luiz Agostinho Ferreira | L. A. Ferreira, Bernard Piette and Wojtek J. Zakrzewski | Wobbles and other kink-breather solutions of the Sine Gordon model | 17 pages, 7 ps figures, latex | Phys.Rev.E77:036613,2008 | 10.1103/PhysRevE.77.036613 | null | hep-th cond-mat.other nlin.SI | null | We study various solutions of the Sine Gordon model in (1+1) dimensions. We
use the Hirota method to construct some of them and then show that the wobble,
discussed in detail by K\"alberman, is one of such solutions. We concentrate
our attention on a kink and its bound states with one or two breathers. We
study their stability and some aspects of their scattering properties on
potential wells and on fixed boundary conditions.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 17:54:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ferreira",
"L. A.",
""
],
[
"Piette",
"Bernard",
""
],
[
"Zakrzewski",
"Wojtek J.",
""
]
] |
0708.1089 | Matteo G. A. Paris | Paolo Zanardi, Matteo G A Paris, Lorenzo Campos Venuti | Quantum criticality as a resource for quantum estimation | 7 pages. Revised and extended version. Gained one author and a
specific example | Phys Rev A vol 78, 042105 (2008) | 10.1103/PhysRevA.78.042105 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We address quantum critical systems as a resource in quantum estimation and
derive the ultimate quantum limits to the precision of any estimator of the
coupling parameters. In particular, if L denotes the size of a system and
\lambda is the relevant coupling parameters driving a quantum phase transition,
we show that a precision improvement of order 1/L may be achieved in the
estimation of \lambda at the critical point compared to the non-critical case.
We show that analogue results hold for temperature estimation in classical
phase transitions. Results are illustrated by means of a specific example
involving a fermion tight-binding model with pair creation (BCS model).
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:18:24 GMT"
},
{
"version": "v2",
"created": "Fri, 1 Aug 2008 15:45:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zanardi",
"Paolo",
""
],
[
"Paris",
"Matteo G A",
""
],
[
"Venuti",
"Lorenzo Campos",
""
]
] |
0708.1090 | Andrey Miroshnichenko | Michael I. Tribelsky, Sergej Flach, Andrey E. Miroshnichenko, Andrey
Gorbach, and Yuri S. Kivshar | Fano resonances at light scattering by an obstacle | 4 pages, 2 figures | null | null | null | cond-mat.other cond-mat.mes-hall cond-mat.soft physics.optics | null | It is shown that elastic resonance scattering of light by a finite-size
obstacle with weak dissipation is analogous to quantum scattering by a
potential with quasi-discrete levels and exhibits Fano resonances. Localized
plasmons (polaritons), exited in the obstacle by the incident light, are
equivalent to the quasi-discrete levels, while the radiative decay of these
excitations plays exactly the same role as tunnelling from the quasi-discrete
levels for the quantum problem. Mie scattering of light by a spherical particle
and an exactly solvable discrete model with nonlocal coupling simulating wave
scattering in systems with reduced spatial dimensionality are discussed as
examples.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:23:16 GMT"
}
] | 2007-09-20T00:00:00 | [
[
"Tribelsky",
"Michael I.",
""
],
[
"Flach",
"Sergej",
""
],
[
"Miroshnichenko",
"Andrey E.",
""
],
[
"Gorbach",
"Andrey",
""
],
[
"Kivshar",
"Yuri S.",
""
]
] |
0708.1091 | Edward S. Letzter | K. R. Goodearl, E. S. Letzter | Semiclassical Limits of Quantum Affine Spaces | 20 pages; LaTeX; Xy-pic; 4 diagrams; to appear in Proc. Edinburgh
Math. Soc | null | null | null | math.QA math.RA | null | Semiclassical limits of generic multiparameter quantized coordinate rings A =
O_q(k^n) of affine spaces are constructed and related to A, for k an
algebraically closed field of characteristic zero and q a multiplicatively
antisymmetric matrix whose entries generate a torsionfree subgroup of k*. A
semiclassical limit of A is a Poisson algebra structure on the corresponding
classical coordinate ring R = O(k^n), and results of Oh, Park, Shin and the
authors are used to construct homeomorphisms from the Poisson prime and Poisson
primitive spectra of R onto the prime and primitive spectra of A. The Poisson
primitive spectrum of R is then identified with the space of symplectic cores
in k^n in the sense of Brown and Gordon, and an example is presented (over the
complex numbers) for which the Poisson primitive spectrum of R is not
homeomorphic to the space of symplectic leaves in k^n. Finally, these results
are extended from quantum affine spaces to quantum affine toric varieties.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:39:33 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Feb 2008 03:37:17 GMT"
}
] | 2008-02-08T00:00:00 | [
[
"Goodearl",
"K. R.",
""
],
[
"Letzter",
"E. S.",
""
]
] |
0708.1092 | Serge Florens | Sabine Andergassen, Pascal Simon, Serge Florens, Denis Feinberg | Spin-orbital Kondo decoherence by environmental effects in capacitively
coupled quantum dot devices | 13 pages, 13 figures. Minor modifications in V2 | Phys. Rev. B 77, 045309 (2008) | 10.1103/PhysRevB.77.045309 | null | cond-mat.mes-hall cond-mat.str-el | null | Strong correlation effects in a capacitively coupled double quantum-dot setup
were previously shown to provide the possibility of both entangling spin-charge
degrees of freedom and realizing efficient spin-filtering operations by static
gate-voltage manipulations. Motivated by the use of such a device for quantum
computing, we study the influence of electromagnetic noise on a general
spin-orbital Kondo model, and investigate the conditions for observing
coherent, unitary transport, crucial to warrant efficient spin manipulations.
We find a rich phase diagram, where low-energy properties sensitively depend on
the impedance of the external environment and geometric parameters of the
system. Relevant energy scales related to the Kondo temperature are also
computed in a renormalization-group treatment, allowing to assess the
robustness of the device against environmental effects.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 12:47:41 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Oct 2007 14:36:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Andergassen",
"Sabine",
""
],
[
"Simon",
"Pascal",
""
],
[
"Florens",
"Serge",
""
],
[
"Feinberg",
"Denis",
""
]
] |
0708.1093 | Torsten B\"oker | Torsten Boeker | Nuclear Star Clusters across the Hubble Sequence | 6 page conference proceedings, to appear in "The impact of HST on
European Astronomy" (41st ESLAB Symposium), pdflatex file, uses svmult.cls
(included) | null | 10.1007/978-90-481-3400-7_19 | null | astro-ph | null | Over the last decade, HST imaging studies have revealed that the centers of
most galaxies are occupied by compact, barely resolved sources. Based on their
structural properties, position in the fundamental plane, and spectra, these
sources clearly have a stellar origin. They are therefore called ``nuclear star
clusters'' (NCs) or ``stellar nuclei''. NCs are found in galaxies of all Hubble
types, suggesting that their formation is intricately linked to galaxy
evolution. In this contribution, I briefly review the results from recent
studies of NCs, touch on some ideas for their formation, and mention some open
issues related to the possible connection between NCs and supermassive black
holes.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 13:06:48 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Boeker",
"Torsten",
""
]
] |
0708.1094 | Mirea Mihail | M. Mirea, L. Tassan-Got, C. Stephan, C.O. Bacri, R.C. Bobulescu | Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross
Section | 17 pages 11 figures | null | 10.1103/PhysRevC.76.064608 | null | nucl-th | null | The structures observed in the sub-threshold neutron-induced fission of
^{232}Th were investigated employing a recent developed model. Theoretical
single-particle excitations of a phenomenological two-humped barrier are
determined by solving a system of coupled differential equations for the motion
along the optimal fission path. A rather good agreement with experimental data
was obtained using a small number of independent parameters. It is predicted
that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial
cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV
is given by a large partial cross section of spin 5/2.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 13:11:04 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Mirea",
"M.",
""
],
[
"Tassan-Got",
"L.",
""
],
[
"Stephan",
"C.",
""
],
[
"Bacri",
"C. O.",
""
],
[
"Bobulescu",
"R. C.",
""
]
] |
0708.1095 | Vladimir Eltsov | V.B. Eltsov, A.I. Golov, R. de Graaf, R. H"anninen, M. Krusius, V.S.
L'vov, R.E. Solntsev | Quantum turbulence in propagating superfluid vortex front | 4 pages, 2 figures | Phys. Rev. Lett. 99, 265301 (2007) | 10.1103/PhysRevLett.99.265301 | null | cond-mat.soft | null | We present experimental, numerical and theoretical studies of a vortex front
propagating into a region of vortex-free flow of rotating superfluid 3He-B. We
show that the nature of the front changes from laminar through quasi-classical
turbulent to quantum turbulent with decreasing temperature. Our experiment
provides the first direct measurement of the dissipation rate in turbulent
vortex dynamics of 3He-B and demonstrates that the dissipation is temperature-
and mutual friction-independent in the T->0 limit, and is strongly suppressed
when the Kelvin-wave cascade on vortex lines is predicted to be involved in the
turbulent energy transfer to smaller length scales.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 13:47:32 GMT"
}
] | 2008-03-05T00:00:00 | [
[
"Eltsov",
"V. B.",
""
],
[
"Golov",
"A. I.",
""
],
[
"de Graaf",
"R.",
""
],
[
"H\"anninen",
"R.",
""
],
[
"Krusius",
"M.",
""
],
[
"L'vov",
"V. S.",
""
],
[
"Solntsev",
"R. E.",
""
]
] |
0708.1096 | Peter B. Gilkey | P. Gilkey and S. Nikcevic | Pseudo-Riemannian Jacobi-Videv Manifolds | null | null | 10.1142/S0219887807002272 | null | math.DG | null | We exhibit several families of Jacobi-Videv pseudo-Riemannian manifolds which
are not Einstein. We also exhibit Jacobi-Videv algebraic curvature tensors
where the Ricci operator defines an almost complex structure.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 13:32:06 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Gilkey",
"P.",
""
],
[
"Nikcevic",
"S.",
""
]
] |
0708.1097 | Francesco Sorrentino Ing | Francesco Sorrentino | Effects of the network structural properties on its controllability | Also available online at: http://link.aip.org/link/?CHA/17/033101 | Chaos (Vol.17, No.3) 2007 | 10.1063/1.2743098 | null | cond-mat.dis-nn | null | In a recent paper, it has been suggested that the controllability of a
diffusively coupled complex network, subject to localized feedback loops at
some of its vertices, can be assessed by means of a Master Stability Function
approach, where the network controllability is defined in terms of the spectral
properties of an appropriate Laplacian matrix. Following that approach, a
comparison study is reported here among different network topologies in terms
of their controllability. The effects of heterogeneity in the degree
distribution, as well as of degree correlation and community structure, are
discussed.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:09:16 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Sorrentino",
"Francesco",
""
]
] |
0708.1098 | Milton Torikachvili | M. S. Torikachvili, S. L. Bud'ko, S. A. Law, M. E. Tillman, E. D. Mun,
and P. C. Canfield | Hydrostatic pressure study of pure and doped La1-xRxAgSb2 (R = Ce, Nd)
charge-density-wave compounds | 22 pages, 11 figures | null | 10.1103/PhysRevB.76.235110 | null | cond-mat.str-el cond-mat.other | null | The intermetallic compound LaAgSb2 displays two charge-density-wave (CDW)
transitions, which were detected with measurements of electrical resistivity
(rho), magnetic susceptibility, and X-ray scattering; the upper transition
takes place at T1 approx. 210 K, and it is accompanied by a large anomaly in
rho(T), whereas the lower transition is marked by a much more subtle anomaly at
T2 approx. 185 K. We studied the effect of hydrostatic pressure (P) on the
formation of the upper CDW state in pure and doped La1-xRxAgSb2 (R = Ce, Nd)
compounds, by means of measurements of rho(T) for P < 23 kbar. We found that
the hydrostatic pressure, as well as the chemical pressure introduced by the
partial substitution of the smaller Ce and Nd ions for La, result in the
suppression of the CDW ground state, e.g. the reduction of the ordering
temperature T1. The values of dT1/dP are approx. 2-4 times higher for the
Ce-doped samples as compared to pure LaAgSb2, or even La0.75Nd0.25AgSb2
Nd-doped with a comparable T1 (P=0). This increased sensitivity to pressure may
be due to increasing Ce- hybridization under pressure. The magnetic ordering
temperature of the cerium-doped compounds is also reduced by pressure, and the
high pressure behavior of the Ce-doped samples is dominated by Kondo impurity
scattering.
| [
{
"version": "v1",
"created": "Tue, 7 Aug 2007 21:24:01 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Oct 2007 12:01:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Torikachvili",
"M. S.",
""
],
[
"Bud'ko",
"S. L.",
""
],
[
"Law",
"S. A.",
""
],
[
"Tillman",
"M. E.",
""
],
[
"Mun",
"E. D.",
""
],
[
"Canfield",
"P. C.",
""
]
] |
0708.1099 | Johan Mauritsson | P. Johnsson, J. Mauritsson, T. Remetter, A. LHuillier, K. J. Schafer | Attosecond Control of Ionization Dynamics | 8 pages, 4 figures | Phys. Rev. Lett. 99, 233001 (2007) | 10.1103/PhysRevLett.99.233001 | null | physics.atom-ph | null | Attosecond pulses can be used to initiate and control electron dynamics on a
sub-femtosecond time scale. The first step in this process occurs when an atom
absorbs an ultraviolet photon leading to the formation of an attosecond
electron wave packet (EWP). Until now, attosecond pulses have been used to
create free EWPs in the continuum, where they quickly disperse. In this paper
we use a train of attosecond pulses, synchronized to an infrared (IR) laser
field, to create a series of EWPs that are below the ionization threshold in
helium. We show that the ionization probability then becomes a function of the
delay between the IR and attosecond fields. Calculations that reproduce the
experimental results demonstrate that this ionization control results from
interference between transiently bound EWPs created by different pulses in the
train. In this way, we are able to observe, for the first time, wave packet
interference in a strongly driven atomic system.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:05:23 GMT"
}
] | 2007-12-11T00:00:00 | [
[
"Johnsson",
"P.",
""
],
[
"Mauritsson",
"J.",
""
],
[
"Remetter",
"T.",
""
],
[
"LHuillier",
"A.",
""
],
[
"Schafer",
"K. J.",
""
]
] |
0708.1100 | Igor Zelenko | Igor Zelenko and Chengbo Li | Differential geometry of curves in Lagrange Grassmannians with given
Young diagram | 26 pages | null | null | null | math.DG | null | Curves in Lagrange Grassmannians appear naturally in the intrinsic study of
geometric structures on manifolds. By a smooth geometric structure on a
manifold we mean any submanifold of its tangent bundle, transversal to the
fibers. One can consider the time-optimal problem naturally associate with a
geometric structure. The Pontryagin extremals of this optimal problem are
integral curves of certain Hamiltonian system in the cotangent bundle. The
dynamics of the fibers of the cotangent bundle w.r.t. this system along an
extremal is described by certain curve in a Lagrange Grassmannian, called
Jacobi curve of the extremal. Any symplectic invariant of the Jacobi curves
produces the invariant of the original geometric structure. The basic
characteristic of a curve in a Lagrange Grassmannian is its Young diagram. The
number of boxes in its kth column is equal to the rank of the kth derivative of
the curve (which is an appropriately defined linear mapping) at a generic
point. We will describe the construction of the complete system of symplectic
invariants for parameterized curves in a Lagrange Grassmannian with given Young
diagram. It allows to develop in a unified way local differential geometry of
very wide classes of geometric structures on manifolds, including both
classical geometric structures such as Riemannian and Finslerian structures and
less classical ones such as sub-Riemannian and sub-Finslerian structures,
defined on nonholonomic distributions.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 17:57:12 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Zelenko",
"Igor",
""
],
[
"Li",
"Chengbo",
""
]
] |
0708.1101 | Sanjay Ram | Sanjay K. Ram, Satyendra Kumar and P. Roca i Cabarrocas | Determination of localized conduction band-tail states distribution in
single phase undoped microcrystalline silicon | 5 pages, 4 figures | null | null | null | cond-mat.mtrl-sci | null | We report on the phototransport properties of microstructurally well
characterized plasma deposited highly crystallized microcrystalline silicon
films. The steady state photoconductivity was measured on a wide
microstructural variety of single-phase undoped microcrystalline silicon films
as a function of temperature and light intensity. The band-tail parameter (kTc)
was calculated from the photoconductivity light intensity exponent values at
different temperatures for a range of quasi-Fermi energies. The localized tail
states distribution in the vicinity of conduction band edge of microcrystalline
silicon was estimated using the values of kTc. Our study shows that
microcrystalline silicon films possessing dissimilar microstructural attributes
exhibit different phototransport behaviors, which are linked to different
features of the density of states maps of the material.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:07:33 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Ram",
"Sanjay K.",
""
],
[
"Kumar",
"Satyendra",
""
],
[
"Cabarrocas",
"P. Roca i",
""
]
] |
0708.1102 | Peter B. Gilkey | C. Dunn, P. Gilkey, and J.H. Park | Spectral geometry, homogeneous spaces, and differential forms with
finite Fourier series | null | null | 10.1088/1751-8113/41/13/135204 | null | math.AP | null | Let G be a compact Lie group acting transitively on Riemannian manifolds M
and N. Let p be a G equivariant Riemannian submersion from M to N. We show that
a smooth differential form on N has finite Fourier series if and only if the
pull back has finite Fourier series on M
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:09:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dunn",
"C.",
""
],
[
"Gilkey",
"P.",
""
],
[
"Park",
"J. H.",
""
]
] |
0708.1103 | Sanjay Ram | Sanjay K. Ram, Satyendra Kumar and P. Roca i Cabarrocas | Normal and anti Meyer-Neldel rule in conductivity of highly crystallized
undoped microcrystalline silicon films | 5 pages, 1 figure | null | 10.1016/j.jnoncrysol.2007.10.051 | null | cond-mat.mtrl-sci | null | We have studied the electrical conductivity behavior of highly crystallized
undoped hydrogenated microcrystalline silicon films having different
microstructures. The dark conductivity is seen to follow Meyer Neldel rule
(MNR) in some films and anti MNR in others, which has been explained on the
basis of variation in the film microstructure and the corresponding changes in
the effective density of states distributions. A band tail transport and
statistical shift of Fermi level are used to explain the origin of MNR as well
as anti-MNR in our samples. The observation of MNR and anti MNR in electrical
transport behavior of microcrystalline silicon is discussed in terms of the
basic underlying physics of their origin and the significance of these
relationships.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:12:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ram",
"Sanjay K.",
""
],
[
"Kumar",
"Satyendra",
""
],
[
"Cabarrocas",
"P. Roca i",
""
]
] |
0708.1104 | Sanjay Ram | Sanjay K. Ram, Satyendra Kumar and P. Roca i Cabarrocas | Fractional composition of large crystallite grains: a unique
microstructural parameter to explain conduction behavior in single phase
undoped microcrystalline silicon | 5 pages, 3 figures | null | 10.1016/j.jnoncrysol.2007.10.049 | null | cond-mat.mtrl-sci | null | We have studied the dark conductivity of a broad microstructural range of
plasma deposited single phase undoped microcrystalline silicon films in a wide
temperature range (15 - 450K) to identify the possible transport mechanisms and
the interrelationship between film microstructure and electrical transport
behavior. Different conduction behaviors seen in films with different
microstructures are explained in the context of underlying transport mechanisms
and microstructural features, for above and below room temperature
measurements. Our microstructural studies have shown that different ranges of
the percentage volume fraction of the constituent large crystallite grains
(Fcl) of the microcrystalline silicon films correspond to characteristically
different and specific microstructures, irrespective of deposition conditions
and thicknesses. Our electrical transport studies demonstrate that each type of
microcrystalline silicon material having a different range of Fcl shows
different electrical transport behaviors.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:19:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ram",
"Sanjay K.",
""
],
[
"Kumar",
"Satyendra",
""
],
[
"Cabarrocas",
"P. Roca i",
""
]
] |
0708.1105 | Hiromichi Kichimi | The Belle Collaboration: K. Abe, et al | Search for \bar{B}^0\to\Lambda_c^+\bar{\Lambda}_c^- decay at Belle | 12 page, 5 figures. Contribution paper for conferences EPS2007 and
Lepton Photon 2007, Belle-Conference-0707 | Phys.Rev.D77:051101,2008 | 10.1103/PhysRevD.77.051101 | null | hep-ex | null | We search for the doubly charmed baryonic decay
$\bar{B}^0\to\Lambda_c^+\bar{\Lambda}_c^-$, in a data sample of $520\times10^6$
$B{\bar B}$ events accumulated at the $\Upsilon(4S)$ resonance with the Belle
detector at the KEKB asymmetric e^+e^- collider. We find no significant signal
and set an upper limit of ${\cal
B}(\bar{B}^0\to\Lambda_c^+\bar{\Lambda}_c^-)<6.2\times10^{-5}$ at 90%
confidence level. The result is significantly below a naive extrapolation from
${\cal B}(B^-\to\Xi_c^0\bar{\Lambda}_c^)$ assuming a simple Cabibbo-suppression
factor of $|V_{cd}/V_{cs}|^2$. The small branching fraction could be attributed
to a suppression due to the large momentum of the baryonic decay products,
which has been observed in other charmed baryonic two-body B decays. trend
observed in other charmed baryonic two-body B decays.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:24:41 GMT"
},
{
"version": "v2",
"created": "Sat, 6 Oct 2007 03:53:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"The Belle Collaboration",
"",
""
],
[
"Abe",
"K.",
""
]
] |
0708.1106 | Shay Fuchs | Shay Fuchs | Additivity of Spin^c Quantization under Cutting | 34 pages | null | null | null | math.DG | null | A G-equivariant spin^c structure on a manifold gives rise to a virtual
representation of the group G, called the spin^c quantization of the manifold.
We present a cutting construction for S^1-equivariant spin^c manifolds, and
show that the quantization of the original manifold is isomorphic to the direct
sum of the quantizations of the cut spaces. Our proof uses Kostant-type
formulas, which express the quantization in terms of local data around the
fixed point set of the S^1-action.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:38:45 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Fuchs",
"Shay",
""
]
] |
0708.1107 | Rebecka Jornsten | Sara L\'opez-Pintado, Rebecka Jornsten | Functional analysis via extensions of the band depth | Published at http://dx.doi.org/10.1214/074921707000000085 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, 103-120 | 10.1214/074921707000000085 | IMS-LNMS54-LNMS5408 | stat.ME | null | The notion of data depth has long been in use to obtain robust location and
scale estimates in a multivariate setting. The depth of an observation is a
measure of its centrality, with respect to a data set or a distribution. The
data depths of a set of multivariate observations translates to a
center-outward ordering of the data. Thus, data depth provides a generalization
of the median to a multivariate setting (the deepest observation), and can also
be used to screen for extreme observations or outliers (the observations with
low data depth). Data depth has been used in the development of a wide range of
robust and non-parametric methods for multivariate data, such as non-parametric
tests of location and scale [Li and Liu (2004)], multivariate rank-tests [Liu
and Singh (1993)], non-parametric classification and clustering [Jornsten
(2004)], and robust regression [Rousseeuw and Hubert (1999)]. Many different
notions of data depth have been developed for multivariate data. In contrast,
data depth measures for functional data have only recently been proposed
[Fraiman and Muniz (1999), L\'{o}pez-Pintado and Romo (2006a)]. While the
definitions of both of these data depth measures are motivated by the
functional aspect of the data, the measures themselves are in fact invariant
with respect to permutations of the domain (i.e. the compact interval on which
the functions are defined). Thus, these measures are equally applicable to
multivariate data where there is no explicit ordering of the data dimensions.
In this paper we explore some extensions of functional data depths, so as to
take the ordering of the data dimensions into account.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:32:41 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"López-Pintado",
"Sara",
""
],
[
"Jornsten",
"Rebecka",
""
]
] |
0708.1108 | Raji Heyrovska | Raji Heyrovska | Linear Depenedences of Van Der Waals, Covalent and Valence Shell Radii
of Atoms of Groups 1a - 8a on their Bohr Radii | 12 pages, one photo, 1 table, 5 figures: Presented as Ohtaki Memorial
Lecture, 10th Eurasia Conference on Chemical Sciences, Manila, January, 2008 | null | null | null | physics.gen-ph physics.chem-ph | null | An earlier finding that the van der waals radii are related to their de
broglie wavelengths for some non-metallic elements has been extended here to
show that in fact, they vary linearly with the ground state bohr radii for all
the elements of groups 1a to 8 a. Similarly, the valence shell radii and the
covalent radii are shown to be linearly dependent on the bohr radii. One table
of data and 5 figures have been provided here showing that all the above radii
are sums of two lengths, one of which is a multiple of the bohr radius and the
other, a positive or negative constant for each group of elements.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:32:53 GMT"
},
{
"version": "v2",
"created": "Tue, 22 Jan 2008 16:50:15 GMT"
}
] | 2008-01-22T00:00:00 | [
[
"Heyrovska",
"Raji",
""
]
] |
0708.1109 | James Grime | James Grime | The hook fusion procedure and its generalisations | Thesis 135 pages | null | null | null | math.RT math.CO | null | The fusion procedure provides a way to construct new solutions to the
Yang-Baxter equation. In the case of the symmetric group the fusion procedure
has been used to construct diagonal matrix elements using a decomposition of
the Young diagram into its rows or columns. We present a new construction which
decomposes the diagram into hooks, the great advantage of this is that it
minimises the number of auxiliary parameters needed in the procedure. We go on
to use the hook fusion procedure to find diagonal matrix elements
computationally and calculate supporting evidence to a previous conjecture.
We are motivated by the construction of certain elements that allow us to
generate representations of the symmetric group and single out particular
irreducible components. In this way we may construct higher representations of
the symmetric group from elementary ones. We go some way to generalising the
hook fusion procedure by considering other decompositions of Young diagrams,
specifically into ribbons. Finally, we adapt our construction to the quantum
deformation of the symmetric group algebra known as the Hecke algebra.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:41:09 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Grime",
"James",
""
]
] |
0708.1110 | Piergiorgio Casella | P. Casella, D. Altamirano, A. Patruno, R. Wijnands and M. van der Klis
(University of Amsterdam) | Discovery of coherent millisecond X-ray pulsations in Aql X-1 | 5 pages, 3 figures, accepted by ApJ Letters after minor revisions.
Slightly extended discussion. One author added. Uses emulateapj.cls | null | 10.1086/528982 | null | astro-ph | null | We report the discovery of an episode of coherent millisecond X-ray pulsation
in the neutron star low-mass X-ray binary Aql X-1. The episode lasts for
slightly more than 150 seconds, during which the pulse frequency is consistent
with being constant. No X-ray burst or other evidence of thermonuclear burning
activity is seen in correspondence with the pulsation, which can thus be
identified as occurring in the persistent emission. The pulsation frequency is
550.27 Hz, very close (0.5 Hz higher) to the maximum reported frequency from
burst oscillations in this source. Hence we identify this frequency with the
neutron star spin frequency. The pulsed fraction is strongly energy dependent,
ranging from <1% (3-5 keV) to >10% (16-30 keV). We discuss possible physical
interpretations and their consequences for our understanding of the lack of
pulsation in most neutron star low-mass X-ray binaries. If interpreted as
accretion-powered pulsation, Aql X-1 might play a key role in understanding the
differences between pulsating and non-pulsating sources.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:17:58 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 13:44:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Casella",
"P.",
"",
"University of Amsterdam"
],
[
"Altamirano",
"D.",
"",
"University of Amsterdam"
],
[
"Patruno",
"A.",
"",
"University of Amsterdam"
],
[
"Wijnands",
"R.",
"",
"University of Amsterdam"
],
[
"van der Klis",
"M.",
"",
"University of Amsterdam"
]
] |
0708.1111 | Jun-Qing Xia | Jun-Qing Xia, Hong Li, Gong-Bo Zhao and Xinmin Zhang | Probing for the Cosmological Parameters with PLANCK Measurement | 15 pages, 8 figures and 3 tables, Accepted for publication in
Int.J.Mod.Phys.D | Int.J.Mod.Phys.D17:2025-2048,2009 | 10.1142/S0218271808013698 | null | astro-ph gr-qc hep-ph hep-th | null | We investigate the constraints on cosmological parameters especially for EoS
of dark energy, inflationary parameters, neutrino mass and curvature of
universe using simulated Planck data. Firstly we determine cosmological
parameters with current observations including ESSENCE, WMAP3, Boomerang-2K2,
CBI, VSA, ACBAR, SDSS LRG and 2dFGRS, and take best-fit model as the fiducial
model in simulations. In simulations we pay attention to the effects of
dynamical dark energy in determination of cosmological parameters. We add
simulated SNAP data to do all the simulations. Using present data, we find
Quintom dark energy model is mildly favored while \LambdaCDM remains a good
fit. In the framework of dynamical dark energy, the constraints on inflationary
parameters, m_{\nu} and \Omega_{K} become weak compared with the constraints in
\LambdaCDM. Intriguingly, we find that the inflationary models with a "blue"
tilt, which are excluded about 2\sigma in \LambdaCDM model, are well within
2\sigma region with the presence of the dynamics of dark energy. The upper
limits of neutrino mass are weakened by a factor of 2 (95% C.L.), say,
m_{\nu}<1.59 eV and m_{\nu}<1.53 eV for two forms of parametrization of the
equation of state of dark energy. The flat universe is a good fit to the
current data, namely, |\Omega_{K}|<0.03 (95% C.L.). With the simulated Planck
and SNAP data, dynamical dark energy and \LambdaCDM might be distinguished at
4\sigma. And uncertainties of inflationary parameters, m_{\nu} and \Omega_{K}
can be reduced obviously. We also constrain the rotation angle \Delta\alpha,
denoting possible cosmological CPT violation, with simulated Planck and CMBpol
data and find that our results are much more stringent than current constraint
and will verify cosmological CPT symmetry with a higher precision. (Abridged)
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:46:44 GMT"
},
{
"version": "v2",
"created": "Wed, 16 Jan 2008 06:40:57 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Xia",
"Jun-Qing",
""
],
[
"Li",
"Hong",
""
],
[
"Zhao",
"Gong-Bo",
""
],
[
"Zhang",
"Xinmin",
""
]
] |
0708.1112 | Alexander Sakhnovich | Alexander Sakhnovich | Weyl functions, inverse problem and special solutions for the system
auxiliary to the nonlinear optics equation | null | Inverse Problems 24 (2008) 025026 | 10.1088/0266-5611/24/2/025026 | null | math-ph math.CA math.MP | null | A Borg-Marchenko type uniqueness theorem (in terms of the Weyl function) is
obtained here for the system auxiliary to the N-wave equation. A procedure to
solve inverse problem is used for this purpose. The asymptotic condition on the
Weyl function, under which the inverse problem is uniquely solvable, is
completed by the new and simple sufficient condition on the potential, granting
the fulfillment of this asymptotic condition. The evolution of the Weyl
function is discussed and the solution of an initial-boundary value problem for
the N-wave equation follows. Explicit solutions of the system are obtained.
System with a shifted argument is treated.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:11:14 GMT"
}
] | 2008-03-18T00:00:00 | [
[
"Sakhnovich",
"Alexander",
""
]
] |
0708.1113 | Philippe Michel | Manfred Einsiedler, Elon Lindenstrauss, Philippe Michel, Akshay
Venkatesh | Distribution of periodic torus orbits and Duke's theorem for cubic
fields | Annals of Maths. (to appear) typos corrected; references updated | Ann. of Math. Volume 173 (2011), Issue 2, Pages 815-885 | 10.4007/annals.2011.173.2.5 | null | math.NT math.DS | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study periodic torus orbits on spaces of lattices. Using the action of the
group of adelic points of the underlying tori, we define a natural equivalence
relation on these orbits, and show that the equivalence classes become
uniformly distributed. This is a cubic analogue of Duke's theorem about the
distribution of closed geodesics on the modular surface: suitably interpreted,
the ideal classes of a cubic totally real field are equidistributed in the
modular 5-fold SL_3(Z)\SL_3(R)/SO_3(R). In particular, this proves (a stronger
form of) the folklore conjecture that the collection of maximal compact flats
in SL_3(Z)\SL_3(R)/SO_3(R) of volume less than V becomes equidistributed as V
goes to infinity. The proof combines subconvexity estimates, measure
classification, and local harmonic analysis.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:03:57 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Feb 2010 11:08:07 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Einsiedler",
"Manfred",
""
],
[
"Lindenstrauss",
"Elon",
""
],
[
"Michel",
"Philippe",
""
],
[
"Venkatesh",
"Akshay",
""
]
] |
0708.1114 | David Sinden | D. Sinden and G.H.M. van der Heijden | Integrability of a conducting elastic rod in a magnetic field | 19 pages, 1 figure | J. Phys. A: Math. Theor. 41, 045207 (2008) | 10.1088/1751-8113/41/4/045207 | null | math-ph math.MP | null | We consider the equilibrium equations for a conducting elastic rod placed in
a uniform magnetic field, motivated by the problem of electrodynamic space
tethers. When expressed in body coordinates the equations are found to sit in a
hierarchy of non-canonical Hamiltonian systems involving an increasing number
of vector fields. These systems, which include the classical Euler and
Kirchhoff rods, are shown to be completely integrable in the case of a
transversely isotropic rod; they are in fact generated by a Lax pair. For the
magnetic rod this gives a physical interpretation to a previously proposed
abstract nine-dimensional integrable system. We use the conserved quantities to
reduce the equations to a four-dimensional canonical Hamiltonian system,
allowing the geometry of the phase space to be investigated through Poincar\'e
sections. In the special case where the force in the rod is aligned with the
magnetic field the system turns out to be superintegrable, meaning that the
phase space breaks down completely into periodic orbits, corresponding to
straight twisted rods.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:05:52 GMT"
}
] | 2010-07-06T00:00:00 | [
[
"Sinden",
"D.",
""
],
[
"van der Heijden",
"G. H. M.",
""
]
] |
0708.1115 | Minhyong Kim | Minhyong Kim | Remark on fundamental groups and effective Diophantine methods for
hyperbolic curves | Submitted to Lang memorial volume | null | null | null | math.NT math.AG | null | We discuss how non-commutative fundamental groups could eventually contribute
to algorithms for finding rational points on hyperbolic curves.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:56:03 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Kim",
"Minhyong",
""
]
] |
0708.1116 | Florian Simatos | Florian Simatos | A variant of the Recoil Growth algorithm to generate multi-polymer
systems | Title changed | null | null | null | cs.CE cond-mat.stat-mech | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Recoil Growth algorithm, proposed in 1999 by Consta et al., is one of the
most efficient algorithm available in the literature to sample from a
multi-polymer system. Such problems are closely related to the generation of
self-avoiding paths. In this paper, we study a variant of the original Recoil
Growth algorithm, where we constrain the generation of a new polymer to take
place on a specific class of graphs. This makes it possible to make a fine
trade-off between computational cost and success rate. We moreover give a
simple proof for a lower bound on the irreducibility of this new algorithm,
which applies to the original algorithm as well.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:07:53 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Sep 2008 10:02:19 GMT"
},
{
"version": "v3",
"created": "Thu, 2 Jul 2009 12:31:15 GMT"
}
] | 2009-07-02T00:00:00 | [
[
"Simatos",
"Florian",
""
]
] |
0708.1117 | Fabrice Mortessagne | Franck Celestini (LPMC), Fabrice Mortessagne (LPMC) | The cosine law at the atomic scale: Toward realistic simulations of
Knudsen diffusion | null | null | 10.1103/PhysRevE.77.021202 | null | cond-mat.stat-mech nlin.CD | null | We propose to revisit the diffusion of atoms in the Knudsen regime in terms
of a complex dynamical reflection process. By means of molecular dynamics
simulation we emphasize the asymptotic nature of the cosine law of reflection
at the atomic scale, and carefully analyze the resulting strong correlations in
the reflection events. A dynamical interpretation of the accomodation
coefficient associated to the slip at the wall interface is also proposed.
Finally, we show that the first two moments of the stochastic process of
reflection non uniformly depend on the incident angle.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 14:59:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Celestini",
"Franck",
"",
"LPMC"
],
[
"Mortessagne",
"Fabrice",
"",
"LPMC"
]
] |
0708.1118 | Craig Roberts | Mandar S. Bhagwat, Lei Chang, Yu-Xin Liu, Craig D. Roberts and Peter
C. Tandy | Flavour symmetry breaking and meson masses | 11 pages, 2 figures | Phys.Rev.C76:045203,2007 | 10.1103/PhysRevC.76.045203 | null | nucl-th hep-ex hep-lat hep-ph nucl-ex | null | The axial-vector Ward-Takahashi identity is used to derive mass formulae for
neutral pseudoscalar mesons. Flavour symmetry breaking entails non-ideal
flavour content for these states. Adding that the \eta^\prime is not a
Goldstone mode, exact chiral-limit relations are developed from the identity.
They connect the dressed-quark propagator to the topological susceptibility. It
is confirmed that in the chiral limit the \eta^\prime mass is proportional to
the matrix element which connects this state to the vacuum via the topological
susceptibility. The implications of the mass formulae are illustrated using an
elementary dynamical model, which includes an Ansatz for that part of the
Bethe-Salpeter kernel related to the non-Abelian anomaly. In addition to the
current-quark masses, the model involves two parameters, one of which is a
mass-scale. It is employed in an analysis of pseudoscalar- and vector-meson
bound-states. While the effects of SU(N_f=2) and SU(N_f=3) flavour symmetry
breaking are emphasised, the five-flavour spectra are described. Despite its
simplicity, the model is elucidative and phenomenologically efficacious; e.g.,
it predicts \eta-\eta^\prime mixing angles of ~ (-15 degrees) and \pi^0-\eta
angles of ~ 1 degree.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:18:12 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 16:51:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bhagwat",
"Mandar S.",
""
],
[
"Chang",
"Lei",
""
],
[
"Liu",
"Yu-Xin",
""
],
[
"Roberts",
"Craig D.",
""
],
[
"Tandy",
"Peter C.",
""
]
] |
0708.1119 | Benne W. Holwerda | B. W. Holwerda, W. C. Keel and A. Bolton | Spiral Disk Opacity from Occulting Galaxy Pairs in the Sloan Digital Sky
Survey | 34 pages, 11 figures, 6 tables | Astron.J.134:2385-2397,2007 | 10.1086/522786 | null | astro-ph | null | A spiral galaxy partially ovelapping a more distant elliptical offers an
unique opportunity to measure the dust extinction in the foreground spiral.
From the Sloan Digital Sky Survey DR4 spectroscopic sample, we selected 83
occulting galaxy pairs and measured disk opacity over the redshift range z =
0.0-0.2 with the goal to determine the recent evolution of disk dust opacity.
The enrichment of the ISM changes over the lifetime of a disk and it is
reasonable to expect the dust extinction properties of spiral disks as a whole
to change over their lifetime. When they do, the change will affect our
measurements of galaxies over the observable universe.
From the SDSS pairs we conclude that spiral disks show evidence of extinction
to ~2 effective radii. However, no evidence for recent evolution of disk
opacity is evident, due to the limited redshift range and our inability to
distinguish other factors on disk opacity such as the presence of spiral arms
and Hubble type. Such effects also mask any relation between surface brightness
and optical depth that has been found in nearby galaxies. Hence, we conclude
that the SDSS spectral catalog is an excellent way to find occulting pairs and
construct a uniform local sample. However, higher resolution than the SDSS
images is needed to disentangle the effects of spiral arms and Hubble type from
evolution since z = 0.2.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 18:37:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Holwerda",
"B. W.",
""
],
[
"Keel",
"W. C.",
""
],
[
"Bolton",
"A.",
""
]
] |
0708.1120 | Miroslava Dessauges-Zavadsky | M. Dessauges-Zavadsky (1), F. Combes (2), D. Pfenniger (1) ((1) Geneva
Observatory, Geneva University, Switzerland, (2) Paris Observatory, LERMA,
France) | Molecular gas in high-velocity clouds: revisited scenario | 9 pages, 4 figures, Accepted for publication in A&A | null | 10.1051/0004-6361:20077277 | null | astro-ph | null | We report a new search for 12CO(1-0) emission in high-velocity clouds (HVCs)
performed with the IRAM 30 m telescope. This search was motivated by the recent
detection of cold dust emission in the HVCs of Complex C. Despite a spatial
resolution which is three times better and sensitivity twice as good compared
to previous studies, no CO emission is detected in the HVCs of Complex C down
to a best 5 sigma limit of 0.16 K km/s at a 22'' resolution. The CO emission
non-detection does not provide any evidence in favor of large amounts of
molecular gas in these HVCs and hence in favor of the infrared findings. We
discuss different configurations which, however, allow us to reconcile the
negative CO result with the presence of molecular gas and cold dust emission.
H2 column densities higher than our detection limit, N(H2) = 3x10^{19} cm^{-2},
are expected to be confined in very small and dense clumps with 20 times
smaller sizes than the 0.5 pc clumps resolved in our observations according to
the results obtained in cirrus clouds, and might thus still be highly diluted.
As a consequence, the inter-clump gas at the 1 pc scale has a volume density
lower than 20 cm^{-3} and already appears as too diffuse to excite the CO
molecules. The observed physical conditions in the HVCs of Complex C also play
an important role against CO emission detection. It has been shown that the
CO-to-H2 conversion factor in low metallicity media is 60 times higher than at
the solar metallicity, leading for a given H2 column density to a 60 times
weaker integrated CO intensity. And the very low dust temperature estimated in
these HVCs implies the possible presence of gas cold enough (< 20 K) to cause
CO condensation onto dust grains under interstellar medium pressure conditions
and thus CO depletion in gas-phase observations.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:04:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dessauges-Zavadsky",
"M.",
""
],
[
"Combes",
"F.",
""
],
[
"Pfenniger",
"D.",
""
]
] |
0708.1121 | Markus Diehl | M. Diehl and W. Kugler | Next-to-leading order corrections in exclusive meson production | 50 pages, 34 figures | Eur.Phys.J.C52:933-966,2007 | 10.1140/epjc/s10052-007-0423-3 | DESY 07-117 | hep-ph | null | We analyze in detail the size of next-to-leading order corrections to hard
exclusive meson production within the collinear factorization approach.
Corrections to the cross section are found to be huge at small xB and
substantial in typical fixed-target kinematics. With the models we take for
nucleon helicity-flip distributions, the transverse target polarization
asymmetry in vector meson production is strongly affected by radiative
corrections, except at large xB. Its overall size is very small for rho
production but can be large in the omega channel.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 11:59:29 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Diehl",
"M.",
""
],
[
"Kugler",
"W.",
""
]
] |
0708.1122 | Collaboration Secretariat Opal | The OPAL collaboration, et al | Bose-Einstein study of position-momentum correlations of charged pions
in hadronic Z0 decays | 25 pages, 10 figures, Submitted to Eur Phys J.C | Eur.Phys.J.C52:787-803,2007 | 10.1140/epjc/s10052-007-0443-z | CERN-PH-EP/2007-025 | hep-ex | null | A study of Bose-Einstein correlations in pairs of identically charged pions
produced in e+e- annihilations at the Z0 peak has been performed for the first
time assuming a non-static emitting source. The results are based on the high
statistics data obtained with the OPAL detector at LEP. The correlation
functions have been analyzed in intervals of the average pair transverse
momentum and of the pair rapidity, in order to study possible correlations
between the pion production points and their momenta (position-momentum
correlations). The Yano-Koonin and the Bertsch-Pratt parameterizations have
been fitted to the measured correlation functions to estimate the geometrical
parameters of the source as well as the velocity of the source elements with
respect to the overall centre-of-mass frame. The source rapidity is found to
scale approximately with the pair rapidity, and both the longitudinal and
transverse source dimensions are found to decrease for increasing average pair
transverse momenta.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:10:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"The OPAL collaboration",
"",
""
]
] |
0708.1123 | Achmad Benny Mutiara | A.B. Mutiara | Dynamical glass transition: critical temperature T_c and memory kernel
in MD-simulated Ni_{0.8}Zr_{0.2} | 9 pages, 14 figures | null | null | null | cond-mat.mtrl-sci cond-mat.stat-mech | null | We use molecular dynamics computer simulations to investigate a critical
temperature T_c for a dynamical glass transition as proposed by the
mode-coupling theory (MCT) of dense liquids in a glass forming
Ni_{0.8}Zr_{0.2}-system. The critical temperature T_c are analyzed from
different quantities and checked the consistency of the estimated values, i.e.
from (i) the non-vanishing nonergodicity parameters as asymptotic solutions of
the MCT equations in the arrested state, (ii) the ${\bf{g}}_m$-parameters
describing the approach of the melt towards the arrested state on the ergodic
side, (iii) the diffusion coefficients in the melt. The resulting T_c values
are found to agree within about 10%.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:20:03 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Mutiara",
"A. B.",
""
]
] |
0708.1124 | Giuseppe Lodato | Giuseppe Lodato (1,2) and J. E. Pringle (2,1) ((1) Department of
Physics and Astronomy, University of Leicester (2) Institute of Astronomy,
Cambridge) | Warp diffusion in accretion discs: a numerical investigation | 17 pages, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12332.x | null | astro-ph | null | In this paper we explore numerically the evolution of a warped accretion
disc. Here, we focus here on the regime where the warp evolves diffusively. By
comparing the numerical results to a simple diffusion model, we are able to
determine the diffusion coefficient of the warp, $\alpha_2$, as a function of
the relevant disc parameters. We find that while in general the disc behaviour
is well reproduced by the diffusion model and for relatively large viscosities
the warp diffusion is well described by the linear theory (in particular
confirming that the warp diffusion coefficient is inversely proportional to
viscosity), significant non-linear effects are present as the viscosity becomes
smaller, but still dominates over wave-propagation effects. In particular, we
find that the inverse dependence of the diffusion coefficient on viscosity
breaks down at low viscosities, so that $\alpha_2$ never becomes larger than a
saturation value $\alpha_{\rm max}$ of order unity. This can have major
consequences in the evolution of systems where a warped disc is present. In
particular, it affects the location of the warp radius in the Bardeen-Petterson
effect and therefore the spin up (or spin down) of supermassive black holes in
the nuclei of galaxies. Additionally, we also find that while the rate of warp
diffusion does not depend significantly on the detailed viscosity formulation,
the rate of internal precession generated by the warp is strongly affected by
it. Such effects should be considered with care when modeling the evolution of
warped discs. This emphasises the need to test the above results using
different numerical schemes, and with higher resolution, in order to
investigate the degree to which numerical simulations are able to provide
accurate modeling of the complex fluid dynamics of warped discs. (Abridged)
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:15:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lodato",
"Giuseppe",
""
],
[
"Pringle",
"J. E.",
""
]
] |
0708.1125 | Alexander Sorin | F. Delduc, O. Lechtenfeld, A.S. Sorin | N=2 supersymmetric unconstrained matrix GNLS hierarchies are consistent | 12 pages, LaTex | Lett.Math.Phys.84:109-122,2008 | 10.1007/s11005-008-0237-8 | ITP-UH-26/06, JINR-E2-2006-170 | nlin.SI hep-th math-ph math.MP | null | We develop a pseudo-differential approach to the N=2 supersymmetric
unconstrained matrix (k|n,m)-Generalized Nonlinear Schroedinger hierarchies and
prove consistency of the corresponding Lax-pair representation
(nlin.SI/0201026). Furthermore, we establish their equivalence to the
integrable hierarchies derived in the super-algebraic approach of the
homogeneously-graded loop superalgebra sl(2k+n|2k+m)\otimes
C[{lambda},{lambda}^{-1}] (nlin.SI/0206037). We introduce an unconventional
definition of N=2 supersymmetric strictly pseudo-differential operators so as
to close their algebra among themselves.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:18:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Delduc",
"F.",
""
],
[
"Lechtenfeld",
"O.",
""
],
[
"Sorin",
"A. S.",
""
]
] |
0708.1126 | Peer Fischer | Ambarish Ghosh, Nicholas K. Sheridon, Peer Fischer | Janus particles with coupled electric and magnetic moments make a
disordered magneto-electric medium | null | null | null | null | cond-mat.mtrl-sci | null | We demonstrate that by combining permanent electric and magnetic moments in
particles, it is possible to realize a new type of medium that allows for a
cross-correlation between electric and magnetic properties of matter, known as
magnetoelectric coupling. Magnetoelectric materials have so far been restricted
to systems that exhibit long-range order in their electric and magnetic
moments. Here, we show that a room-temperature, switchable magnetoelectric can
be realized that is naturally disordered. The building blocks are Tellegen
particles that orient in either an electric or a magnetic field.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:59:04 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Ghosh",
"Ambarish",
""
],
[
"Sheridon",
"Nicholas K.",
""
],
[
"Fischer",
"Peer",
""
]
] |
0708.1127 | Sylvie Leray | E. Le Gentil, T. Aumann, C.O. Bacri, J. Benlliure, S. Bianchin, M.
B\"ohmer, A. Boudard, J. Brzychczyk, E. Casarejos, M. Combet, L. Donadille,
J.E. Ducret, M. Fernandez-Ordo\~nez, R. Gernh\"auser, H. Johansson, K.
Kezzar, T. Kurtukian-Nieto, A. Lafriakh, F. Lavaud, A. Le F\`evre, S. Leray,
J. L\"uhning, J. Lukasik, U. Lynen, W.F. M\"uller, P. Pawlowski, S. Pietri,
F. Rejmund, C. Schwarz, C. Sfienti, H. Simon, W. Trautmann, C. Volant, O.
Yordanov | Coincidence measurement of residues and light particles in the reaction
56Fe+p at 1 GeV per nucleon with SPALADIN | 4 pages, 5 figures, revised version accepted in Phys. Rev. Lett | Phys.Rev.Lett.100:022701,2008 | 10.1103/PhysRevLett.100.022701 | null | nucl-ex | null | The spallation of $^{56}$Fe in collisions with hydrogen at 1 A GeV has been
studied in inverse kinematics with the large-aperture setup SPALADIN at GSI.
Coincidences of residues with low-center-of-mass kinetic energy light particles
and fragments have been measured allowing the decomposition of the total
reaction cross-section into the different possible de-excitation channels.
Detailed information on the evolution of these de-excitation channels with
excitation energy has also been obtained. The comparison of the data with
predictions of several de-excitation models coupled to the INCL4 intra-nuclear
cascade model shows that only GEMINI can reasonably account for the bulk of
collected results, indicating that in a light system with no compression and
little angular momentum, multifragmentation might not be necessary to explain
the data.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:48:15 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Nov 2007 16:24:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gentil",
"E. Le",
""
],
[
"Aumann",
"T.",
""
],
[
"Bacri",
"C. O.",
""
],
[
"Benlliure",
"J.",
""
],
[
"Bianchin",
"S.",
""
],
[
"Böhmer",
"M.",
""
],
[
"Boudard",
"A.",
""
],
[
"Brzychczyk",
"J.",
""
],
[
"Casarejos",
"E.",
""
],
[
"Combet",
"M.",
""
],
[
"Donadille",
"L.",
""
],
[
"Ducret",
"J. E.",
""
],
[
"Fernandez-Ordoñez",
"M.",
""
],
[
"Gernhäuser",
"R.",
""
],
[
"Johansson",
"H.",
""
],
[
"Kezzar",
"K.",
""
],
[
"Kurtukian-Nieto",
"T.",
""
],
[
"Lafriakh",
"A.",
""
],
[
"Lavaud",
"F.",
""
],
[
"Fèvre",
"A. Le",
""
],
[
"Leray",
"S.",
""
],
[
"Lühning",
"J.",
""
],
[
"Lukasik",
"J.",
""
],
[
"Lynen",
"U.",
""
],
[
"Müller",
"W. F.",
""
],
[
"Pawlowski",
"P.",
""
],
[
"Pietri",
"S.",
""
],
[
"Rejmund",
"F.",
""
],
[
"Schwarz",
"C.",
""
],
[
"Sfienti",
"C.",
""
],
[
"Simon",
"H.",
""
],
[
"Trautmann",
"W.",
""
],
[
"Volant",
"C.",
""
],
[
"Yordanov",
"O.",
""
]
] |
0708.1128 | Eric R. Bittner | Arkadiusz Czader, Eric R. Bittner | Calculations of the Exciton Coupling Elements Between the DNA Bases
Using the Transition Density Cube Method | null | J. Chem. Phys. 128, 035101 (2008) | 10.1063/1.2821384 | null | cond-mat.soft | null | Excited states of the of the double-stranded DNA model
(A)$_{12}\cdot$(T)_{12} were calculated in the framework of the exciton theory.
The off-diagonal elements of the exciton matrix were calculated using the
transition densities and ideal dipole approximation associated with the lowest
energy $\pi\pi^{*}$ excitations of the individual nucleobases obtained from
TDDFT calculations. The values of the coupling calculated with the transition
density cubes (TDC) and ideal-dipole approximation (IDA) methods were found
significantly different for the small inter-chromophore distances. It was shown
that the IDA overestimates the coupling significantly. The effects of the
structural fluctuations were incorporated by averaging the properties of the
excited states over a large number of conformations obtained from the MD
simulations.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:14:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Czader",
"Arkadiusz",
""
],
[
"Bittner",
"Eric R.",
""
]
] |
0708.1129 | Robert Prevedel | Robert Prevedel, Andre Stefanov, Philip Walther and Anton Zeilinger | Experimental realization of a quantum game on a one-way quantum computer | 13 pages, 4 figures | New Journal of Physics 9 (2007) 205 | 10.1088/1367-2630/9/6/205 | null | quant-ph | null | We report the first demonstration of a quantum game on an all-optical one-way
quantum computer. Following a recent theoretical proposal we implement a
quantum version of Prisoner's Dilemma, where the quantum circuit is realized by
a 4-qubit box-cluster configuration and the player's local strategies by
measurements performed on the physical qubits of the cluster. This
demonstration underlines the strength and versatility of the one-way model and
we expect that this will trigger further interest in designing quantum
protocols and algorithms to be tested in state-of-the-art cluster resources.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:27:37 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Prevedel",
"Robert",
""
],
[
"Stefanov",
"Andre",
""
],
[
"Walther",
"Philip",
""
],
[
"Zeilinger",
"Anton",
""
]
] |
0708.1130 | Regina Liu | Regina Liu, William Strawderman, Cun-Hui Zhang | Complex Datasets and Inverse Problems. Tomography, Networks and Beyond | Published at http://dx.doi.org/10.1214/074921707000000229 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org) | IMS Lecture Notes Monograph Series 2007, Vol. 54, i-viii | 10.1214/074921707000000229 | IMS-LNMS54-LNMS54PR | math.ST stat.TH | null | This book is a collection of papers dedicated to the memory of Yehuda Vardi.
Yehuda was the chair of the Department of Statistics of Rutgers University when
he passed away unexpectedly on January 13, 2005. On October 21--22, 2005, some
150 leading scholars from many different fields, including statistics,
telecommunications, biomedical engineering, bioinformatics, biostatistics and
epidemiology, gathered at Rutgers in a conference in his honor. This conference
was on ``Complex Datasets and Inverse Problems: Tomography, Networks, and
Beyond,'' and was organized by the editors. The present collection includes
research work presented at the conference, as well as contributions from
Yehuda's colleagues. The theme of the conference was networks and other
important and emerging areas of research involving incomplete data and
statistical inverse problems. Networks are abundant around us: communication,
computer, traffic, social and energy are just a few examples. As enormous
amounts of network data are collected in this information age, the field has
attracted a great amount of attention from researchers in statistics and
computer engineering as well as telecommunication providers and various
government agencies. However, few statistical tools have been developed for
analyzing network data as they are typically governed by time-varying and
mutually dependent communication protocols sitting on complicated
graph-structured network topologies. Many prototypical applications in these
and other important technologies can be viewed as statistical inverse problems
with complex, massive, high-dimensional and possibly biased/incomplete data.
This unifying theme of inverse problems is particularly appropriate for a
conference and volume dedicated to the memory of Yehuda. Indeed he made
influential contributions to these fields, especially in medical tomography,
biased data, statistical inverse problems, and network tomography.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:28:13 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Liu",
"Regina",
""
],
[
"Strawderman",
"William",
""
],
[
"Zhang",
"Cun-Hui",
""
]
] |
0708.1131 | Andrew Comech | Alexander Komech, Andrew Komech | Global attraction to solitary waves for Klein-Gordon equation with mean
field interaction | null | null | null | null | math-ph math.MP | null | We consider a U(1)-invariant nonlinear Klein-Gordon equation in dimension one
or larger, self-interacting via the mean field mechanism. We analyze the
long-time asymptotics of finite energy solutions and prove that, under certain
generic assumptions, each solution converges (as time goes to infinity) to the
two-dimensional set of all ``nonlinear eigenfunctions'' of the form
$\phi(x)e\sp{-i\omega t}$. This global attraction is caused by the nonlinear
energy transfer from lower harmonics to the continuous spectrum and subsequent
dispersive radiation.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:34:46 GMT"
},
{
"version": "v2",
"created": "Sat, 10 Nov 2007 17:59:02 GMT"
},
{
"version": "v3",
"created": "Tue, 11 Mar 2008 01:44:25 GMT"
}
] | 2008-03-11T00:00:00 | [
[
"Komech",
"Alexander",
""
],
[
"Komech",
"Andrew",
""
]
] |
0708.1132 | Luca Amendola | Luca Amendola (INAF/OAR), Claudia Quercellini (U. Tor Vergata, Italy),
Amedeo Balbi (U. Tor Vergata and INFN, Italy) | Peculiar acceleration | 9 pages | Phys.Lett.B660:81-86,2008 | 10.1016/j.physletb.2007.11.094 | null | astro-ph | null | It has been proposed recently to observe the change in cosmological redshift
of distant galaxies or quasars with the next generation of large telescope and
ultra-stable spectrographs (the so-called Sandage-Loeb test). Here we
investigate the possibility of observing the change in peculiar velocity in
nearby clusters and galaxies. This ``peculiar acceleration'' could help
reconstructing the gravitational potential without assuming virialization. We
show that the expected effect is of the same order of magnitude of the
cosmological velocity shift. Finally, we discuss how to convert the theoretical
predictions into quantities directly related to observations.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:34:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Amendola",
"Luca",
"",
"INAF/OAR"
],
[
"Quercellini",
"Claudia",
"",
"U. Tor Vergata, Italy"
],
[
"Balbi",
"Amedeo",
"",
"U. Tor Vergata and INFN, Italy"
]
] |
0708.1133 | E. H. Hwang | E. H. Hwang and S. Das Sarma | The quasiparticle spectral function in doped graphene | 5 pages, 3 figures | Phys. Rev. B 77, 081412(R) (2008) | 10.1103/PhysRevB.77.081412 | null | cond-mat.mes-hall cond-mat.dis-nn | null | We calculate the real and imaginary electron self-energy as well as the
quasiparticle spectral function in doped graphene taking into account
electron-electron interaction in the leading order dynamically screened Coulomb
coupling. Our theory provides the basis for calculating {\it all} one-electron
properties of extrinsic graphene. Comparison with existing ARPES measurements
shows broad qualitative agreement between theory and experiment. We also
calculate the renormalized graphene momentum distribution function, finding a
typical Fermi liquid discontinuity at k_F. We also provide a critical
discussion of the relevant many body approximations (e.g. RPA) for graphene.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:58:10 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 21:12:33 GMT"
}
] | 2008-05-12T00:00:00 | [
[
"Hwang",
"E. H.",
""
],
[
"Sarma",
"S. Das",
""
]
] |
0708.1134 | Nenad Vukmirovi\'c | Nenad Vukmirovi\'c, Zoran Ikoni\'c, Dragan Indjin and Paul Harrison | Quantum transport in semiconductor quantum dot superlattices:
electron-phonon resonances and polaron effects | null | Phys. Rev. B 76, 245313 (2007) | 10.1103/PhysRevB.76.245313 | null | cond-mat.mes-hall | null | Electron transport in periodic quantum dot arrays in the presence of
interactions with phonons was investigated using the formalism of
nonequilibrium Green's functions. The self-consistent Born approximation was
used to model the self-energies. Its validity was checked by comparison with
the results obtained by direct diagonalization of the Hamiltonian of
interacting electrons and longitudinal optical phonons. The nature of charge
transport at electron -- phonon resonances was investigated in detail and
contributions from scattering and coherent tunnelling to the current were
identified. It was found that at larger values of the structure period the main
peak in the current -- field characteristics exhibits a doublet structure which
was shown to be a transport signature of polaron effects. At smaller values of
the period, electron -- phonon resonances cause multiple peaks in the
characteristics. A phenomenological model for treatment of nonuniformities of a
realistic quantum dot ensemble was also introduced to estimate the influence of
nonuniformities on current -- field characteristics.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:44:14 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 02:27:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vukmirović",
"Nenad",
""
],
[
"Ikonić",
"Zoran",
""
],
[
"Indjin",
"Dragan",
""
],
[
"Harrison",
"Paul",
""
]
] |
0708.1135 | Tamar Mentzel | T. S. Mentzel, V. J. Porter, S. Geyer, K. MacLean, M. G. Bawendi, M.
A. Kastner | Charge transport in arrays of PbSe nanocrystals | 8 pages,10 figures | null | null | null | cond-mat.mes-hall | null | We report electrical transport measurements of arrays of PbSe nanocrystals
forming the channels of field effect transistors. We measure the current in
these devices as a function of source-drain voltage, gate voltage and
temperature. Annealing is necessary to observe measurable current after which a
simple model of hopping between intrinsic localized states describes the
transport properties of the nanocrystal solid. We find that the majority
carriers are holes, which are thermally released from acceptor states. At low
source-drain voltages, the activation energy for the conductivity is given by
the energy required to generate holes plus the activation over barriers
resulting from site disorder. At high source-drain voltages the activation
energy is given by the former only. The thermal activation energy of the
zero-bias conductance indicates that the Fermi energy is close to the
highest-occupied valence level, the 1Sh state, and this is confirmed by
field-effect measurements, which give a density of states of approximately
eight per nanocrystal as expected from the degeneracy of the 1Sh state.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:39:14 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Jan 2008 21:32:33 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Mentzel",
"T. S.",
""
],
[
"Porter",
"V. J.",
""
],
[
"Geyer",
"S.",
""
],
[
"MacLean",
"K.",
""
],
[
"Bawendi",
"M. G.",
""
],
[
"Kastner",
"M. A.",
""
]
] |
0708.1136 | Zeba Wunderlich | Zeba Wunderlich, Leonid A. Mirny | Spatial effects on the speed and reliability of protein-DNA search | 16 pages, 4 figures | Nucleic Acids Res. 2008 May 3 | 10.1093/nar/gkn173 | null | q-bio.BM | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Strong experimental and theoretical evidence shows that transcription factors
and other specific DNA-binding proteins find their sites using a two-mode
search: alternating between 3D diffusion through the cell and 1D sliding along
the DNA. We consider the role spatial effects in the mechanism on two different
scales. First, we reconcile recent experimental findings by showing that the 3D
diffusion of the transcription factor is often local, i.e. the transcription
factor lands quite near its dissociation site. Second, we discriminate between
two types of searches: global searches and local searches. We show that these
searches differ significantly in average search time and the variability of
search time. Using experimentally measured parameter values, we also show that
1D and 3D search is not optimally balanced, leading to much larger estimates of
search time. Together, these results lead to a number of biological
implications including suggestions of how prokaryotes and eukaryotes achieve
rapid gene regulation and the relationship between the search mechanism and
noise in gene expression.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 19:36:39 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Dec 2007 17:06:05 GMT"
},
{
"version": "v3",
"created": "Wed, 11 Jun 2008 17:23:35 GMT"
}
] | 2008-06-11T00:00:00 | [
[
"Wunderlich",
"Zeba",
""
],
[
"Mirny",
"Leonid A.",
""
]
] |
0708.1137 | Spiros Evangelou | Yue Yin, D.E. Katsanos and S.N. Evangelou | Quantum Walks on a Random Environment | 7 pages 8 figures (for high resolution figures send an email to
[email protected]) | null | 10.1103/PhysRevA.77.022302 | null | quant-ph cond-mat.dis-nn | null | Quantum walks are considered in a one-dimensional random medium characterized
by static or dynamic disorder. Quantum interference for static disorder can
lead to Anderson localization which completely hinders the quantum walk and it
is contrasted with the decoherence effect of dynamic disorder having strength
W, where a quantum to classical crossover at time $t_{c}\propto W^{-2}$
transforms the quantum walk into an ordinary random walk with diffusive
spreading. We demonstrate these localization and decoherence phenomena in
quantum carpets of the observed time evolution and examine in detail a dimer
lattice which corresponds to a single qubit subject to randomness.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:43:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yin",
"Yue",
""
],
[
"Katsanos",
"D. E.",
""
],
[
"Evangelou",
"S. N.",
""
]
] |
0708.1138 | Sharon Toolan | Lynn Redding Carlson, E. Sabbi, M. Sirianni, J. L. Hora, A. Nota, M.
Meixner, J. S. Gallagher III, M. S. Oey, A. Pasquali, L. J. Smith, M. Tosi,
R. Walterbos | Progressive star formation in the young SMC cluster NGC 602 | Accepted to ApJL; 14 pages, 5 figures | null | null | STScI Eprint #1769 | astro-ph | null | NGC 602 is a young stellar cluster located in a peripheral region of the
Small Magellanic Cloud known as the wing. Far from the main body of the galaxy
and abutting the Magellanic Bridge, the SMC's wing is characterized by low gas
and stellar content. With deep optical imaging from the Advanced Camera for
Surveys (ACS) aboard the Hubble Space Telescope (HST), we have discovered an
extensive pre-Main Sequence (PMS) population, with stellar masses in the range
0.6-3 Solar masses. These low mass PMS stars formed coevally with the central
cluster about 4 Myr ago. Spitzer Space Telescope (Spitzer) images of the same
region from the Infrared Array Camera (IRAC) also reveal a population of Young
Stellar Objects (YSOs), some of which are still embedded in nebular material
and most of which likely formed even more recently than the young stars
detected with HST/ACS imaging. We infer that star formation started in this
region about 4 Myr ago with the formation of the central cluster and gradually
propagated towards the outskirts where star formation is presently ongoing.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 18:59:12 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Carlson",
"Lynn Redding",
""
],
[
"Sabbi",
"E.",
""
],
[
"Sirianni",
"M.",
""
],
[
"Hora",
"J. L.",
""
],
[
"Nota",
"A.",
""
],
[
"Meixner",
"M.",
""
],
[
"Gallagher",
"J. S.",
"III"
],
[
"Oey",
"M. S.",
""
],
[
"Pasquali",
"A.",
""
],
[
"Smith",
"L. J.",
""
],
[
"Tosi",
"M.",
""
],
[
"Walterbos",
"R.",
""
]
] |
0708.1139 | Michael Stone | Michael Stone, Dmitry Gutman | The Quantum Hydrodynamics of the Sutherland Model | 23 pages, revtex4, typos corrected, 1 reference added | Journal of Physics A: Mathematical and Theoretical 41, 025209
(2008) | 10.1088/1751-8113/41/2/025209 | null | cond-mat.str-el cond-mat.mes-hall hep-th | null | We show that the form of the chiral condition found by Abanov et al., in the
quantum hydrodyamics of the Sutherland model arises because there are two
distinct inner products with respect to which the chiral Hamitonian hermitian,
but only one with respect to which the full, non-chiral, Hamiltonian is
hermitian.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 15:54:36 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 14:52:06 GMT"
}
] | 2009-03-29T00:00:00 | [
[
"Stone",
"Michael",
""
],
[
"Gutman",
"Dmitry",
""
]
] |
0708.1140 | Kostya Trachenko | K Trachenko and V V Brazhkin | Liquid elasticity length, universal dynamic crossovers and glass
transition | null | J. Phys.: Condens. Matter 20, 075103 (2008) | 10.1088/0953-8984/20/7/075103 | null | cond-mat.dis-nn | null | We discuss two main universal dynamic crossovers in a liquid that correspond
to relaxation times of 1 ps and 10^{-7}--10^{-6} s. We introduce the concept of
liquid elasticity length $d_{\rm el}$. At room temperature, $d_{\rm el}$ is
several \AA in water and increases to 0.01 mm in honey and 1 mm in tar. We
discuss that on temperature decrease, $d_{\rm el}=d_{\rm m}$ and $d_{\rm el}=L$
correspond to the two dynamic crossovers, where $d_{\rm m}$ is the medium-range
order and L is system size. The second crossover defines all kinetic aspects of
the glass transition whereas ``thermodynamic'' glass transition is realized in
the limit of infinite system size only. One prediction of this picture is the
increase of viscosity with the size of macroscopic system, which we verify by
measuring the viscosity of honey.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:39:54 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 19:32:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Trachenko",
"K",
""
],
[
"Brazhkin",
"V V",
""
]
] |
0708.1141 | Richard Price | Christopher Beetle, Benjamin Bromley, Napole\'on Hern\'andez and
Richard H. Price | The periodic standing-wave approximation: post-Minkowski computation | 19 pages, 3 figures, 1 table, RevTeX | Phys.Rev.D76:084016,2007 | 10.1103/PhysRevD.76.084016 | null | gr-qc | null | The periodic standing wave method studies circular orbits of compact objects
coupled to helically symmetric standing wave gravitational fields. From this
solution an approximation is extracted for the strong field, slowly
inspiralling motion of black holes and binary stars. Previous work on this
model has dealt with nonlinear scalar models, and with linearized general
relativity. Here we present the results of the method for the post-Minkowski
(PM) approximation to general relativity, the first step beyond linearized
gravity. We compute the PM approximation in two ways: first, via the standard
approach of computing linearized gravitational fields and constructing from
them quadratic driving sources for second-order fields, and second, by solving
the second-order equations as an ``exact'' nonlinear system. The results of
these computations have two distinct applications: (i) The computational
infrastructure for the ``exact'' PM solution will be directly applicable to
full general relativity. (ii) The results will allow us to begin supplying
initial data to collaborators running general relativistic evolution codes.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:07:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Beetle",
"Christopher",
""
],
[
"Bromley",
"Benjamin",
""
],
[
"Hernández",
"Napoleón",
""
],
[
"Price",
"Richard H.",
""
]
] |
0708.1142 | Ruggero Vaia | Alessandro Cuccoli, Alessio Taiti, Ruggero Vaia, Paola Verrucchi | Extracting signatures of quantum criticality in the finite-temperature
behavior of many-body systems | 10 pages, 12 figures | Phys. Rev. B 76, 064405 (2007) | 10.1103/PhysRevB.76.064405 | null | cond-mat.stat-mech | null | We face the problem of detecting and featuring footprints of quantum
criticality in the finite-temperature behavior of quantum many-body systems.
Our strategy is that of comparing the phase diagram of a system displaying a
T=0 quantum phase transition with that of its classical limit, in order to
single out the genuinely quantum effects. To this aim, we consider the
one-dimensional Ising model in a transverse field: while the quantum S=1/2
Ising chain is exactly solvable and extensively studied, results for the
classical limit (infinite S) of such model are lacking, and we supply them
here. They are obtained numerically, via the Transfer-matrix method, and their
asymptotic low-temperature behavior is also derived analytically by
self-consistent spin-wave theory. We draw the classical phase-diagram according
to the same procedure followed in the quantum analysis, and the two phase
diagrams are found unexpectedly similar: Three regimes are detected also in the
classical case, each characterized by a functional dependence of the
correlation length on temperature and field analogous to that of the quantum
model. What discriminates the classical from the quantum case are the different
values of the exponents entering such dependencies, a consequence of the
different nature of zero-temperature quantum fluctuations with respect to
thermal ones.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:23:07 GMT"
}
] | 2007-08-09T00:00:00 | [
[
"Cuccoli",
"Alessandro",
""
],
[
"Taiti",
"Alessio",
""
],
[
"Vaia",
"Ruggero",
""
],
[
"Verrucchi",
"Paola",
""
]
] |
0708.1143 | N. P. Ong | J. G. Checkelsky, Minhyea Lee, E. Morosan, R. J. Cava and N. P. Ong | The anomalous Hall Effect and magnetoresistance in the layered
ferromagnet Fe_{1/4}TaS_2: the inelastic regime | 10 pages, 11 figures | Phys. Rev. B 77, 014433 (2008) | 10.1103/PhysRevB.77.014433 | null | cond-mat.str-el cond-mat.mes-hall | null | The large magnetic anisotropy in the layered ferromagnet Fe_{1/4}TaS_2 leads
to very sharp reversals of the magnetization $\bf M$ at the coercive field. We
have exploited this feature to measure the anomalous Hall effect (AHE),
focussing on the AHE conductivity $\sigma^A_{xy}$ in the inelastic regime. At
low temperature T (5-50 K), $\sigma^A_{xy}$ is T-independent, consistent with
the Berry-phase/Karplus-Luttinger theory. Above 50 K, we extract an inelastic
AHE conductivity $\sigma^{in}_{xy}$ that scales as the square of $\Delta\rho$
(the T dependent part of the resistivity $\rho$). The term $\sigma^{in}_{xy}$
clarifies the T dependence and sign-reversal of the AHE coefficient R_s(T). We
discuss the possible ubiquity of $\sigma^{in}_{xy}$ in ferromagnets, and ideas
for interpreting its scaling with $(\Delta\rho)^2$. Measurements of the
magnetoresistance (MR) reveal a rich pattern of behavior vs. T and field
tilt-angle. We show that the 2 mechanisms, the anisotropic MR effect and
field-suppression of magnons, account for the intricate MR behavior, including
the bow-tie features caused by the sharp reversals in $\bf M$.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:21:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Checkelsky",
"J. G.",
""
],
[
"Lee",
"Minhyea",
""
],
[
"Morosan",
"E.",
""
],
[
"Cava",
"R. J.",
""
],
[
"Ong",
"N. P.",
""
]
] |
0708.1144 | Guenter Sigl | Kathrin A. Hochmuth (MPI Munich), Guenter Sigl (APC and IAP, Paris) | Effects of Axion-Photon Mixing on Gamma-Ray Spectra from Magnetized
Astrophysical Sources | 9 revtex pages, 3 eps figures included | Phys.Rev.D76:123011,2007 | 10.1103/PhysRevD.76.123011 | null | astro-ph hep-ph | null | Astrophysical gamma-ray sources come in a variety of sizes and
magnetizations. We deduce general conditions under which gamma-ray spectra from
such sources would be significantly affected by axion-photon mixing. We show
that, depending on strength and coherence of the magnetic field, axion
couplings down to ~ 1/(10**13 GeV) can give rise to significant axion-photon
conversions in the environment of accreting massive black holes. Resonances can
occur between the axion mass term and the plasma frequency term as well as
between the plasma frequency term and the vacuum Cotton-Mouton shift. Both
resonances and non-resonant transitions could induce detectable features or
even strong suppressions in finite energy intervals of gamma-ray spectra from
active galactic nuclei. Such effects can occur at keV to TeV energies for
couplings that are currently allowed by all experimental constraints.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:31:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hochmuth",
"Kathrin A.",
"",
"MPI Munich"
],
[
"Sigl",
"Guenter",
"",
"APC and IAP, Paris"
]
] |
0708.1145 | Ian Heywood | Ian Heywood, Katherine M. Blundell, Steve Rawlings | The prevalence of FRI radio quasars | 11 pages, 6 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Society | null | 10.1111/j.1365-2966.2007.12278.x | null | astro-ph | null | We present deep, multi-VLA-configuration radio images for a set of 18
quasars, having redshifts between 0.36 and 2.5, from the 7C quasar survey.
Approximately one quarter of these quasars have FRI-type twin-jet structures
and the remainder are a broad range of wide angle tail, fat double, classical
double, core-jet and hybrid sources. These images demonstrate that FRI quasars
are prevalent in the universe, rather than non-existent as had been suggested
in the literature prior to the serendipitous discovery of the first FRI quasar
a few years ago, the optically powerful "radio quiet" quasar E1821+643. Some of
the FRI quasars have radio luminosities exceeding the traditional FRI / FRII
break luminosity, however we find no evidence for FRII quasars with
luminosities significantly below the break. We consider whether the existence
of such high luminosity FRI structures is due to the increasingly inhomogeneous
environments in the higher redshift universe.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:34:11 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Heywood",
"Ian",
""
],
[
"Blundell",
"Katherine M.",
""
],
[
"Rawlings",
"Steve",
""
]
] |
0708.1146 | Yingdong Lu | Grace Lin, Yingdong Lu, David Yao | Stochastic Knapsack Problem Revisited: Switch-Over Policies and Dynamic
Pricing | null | null | null | null | q-fin.PR math.OC math.PR | null | The stochastic knapsack has been used as a model in wide ranging applications
from dynamic resource allocation to admission control in telecommunication. In
recent years, a variation of the model has become a basic tool in studying
problems that arise in revenue management and dynamic/flexible pricing; and it
is in this context that our study is undertaken. Based on a dynamic programming
formulation and associated properties of the value function, we study in this
paper a class of control that we call switch-over policies -- start from
accepting only orders of the highest price, and switch to including lower
prices as time goes by, with the switch-over times optimally decided via convex
programming. We establish the asymptotic optimality of the switch-over policy,
and develop pricing models based on this policy to optimize the price
reductions over the decision horizon.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:38:04 GMT"
}
] | 2008-12-02T00:00:00 | [
[
"Lin",
"Grace",
""
],
[
"Lu",
"Yingdong",
""
],
[
"Yao",
"David",
""
]
] |
0708.1147 | Kaifu Luo | Kaifu Luo, Tapio Ala-Nissila, See-chen Ying, and Aniket Bhattacharya | Influence of polymer-pore interactions on translocation | 4 pages, 5 figures, Submitted to Phys. Rev. Lett | Phys. Rev. Lett. 99, 148102 (2007) | 10.1103/PhysRevLett.99.148102 | null | cond-mat.soft cond-mat.stat-mech | null | We investigate the influence of polymer-pore interactions on the
translocation dynamics using Langevin dynamics simulations. An attractive
interaction can greatly improve translocation probability. At the same time, it
also increases translocation time slowly for weak attraction while exponential
dependence is observed for strong attraction. For fixed driving force and chain
length the histogram of translocation time has a transition from Gaussian
distribution to long-tailed distribution with increasing attraction. Under a
weak driving force and a strong attractive force, both the translocation time
and the residence time in the pore show a non-monotonic behavior as a function
of the chain length. Our simulations results are in good agreement with recent
experimental data.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:39:06 GMT"
}
] | 2007-10-01T00:00:00 | [
[
"Luo",
"Kaifu",
""
],
[
"Ala-Nissila",
"Tapio",
""
],
[
"Ying",
"See-chen",
""
],
[
"Bhattacharya",
"Aniket",
""
]
] |
0708.1148 | Ualbai Umirbaev | Leonid Makar-Limanov, Umut Turusbekova, and Ualbai Umirbaev | Automorphisms and derivations of free Poisson algebras in two variables | 11 pages | J. Algebra 322 (2009), no. 9, 3318-3330 | null | null | math.RA math.SG | null | Let P be a free Poisson algebra in two variables over a field of
characteristic zero. We prove that the automorphisms of P are tame and that the
locally nilpotent derivations of P are triangulable.
| [
{
"version": "v1",
"created": "Wed, 8 Aug 2007 16:41:23 GMT"
}
] | 2020-01-03T00:00:00 | [
[
"Makar-Limanov",
"Leonid",
""
],
[
"Turusbekova",
"Umut",
""
],
[
"Umirbaev",
"Ualbai",
""
]
] |
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