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arxiv_dataset-28001108.1962 | Violation of the zeroth law of thermodynamics for a non-ergodic
interaction
cond-mat.stat-mech quant-ph
The phenomenon described by our title should surprise no one. What may be
surprising though is how easy it is to produce a quantum system with this
feature; moreover, that system is one that is often used for the purpose of
showing how systems equilibrate. The violation can be variously manifested. In
our detailed example, bringing a detuned 2-level system into contact with a
monochromatic reservoir does not cause it to relax to the reservoir
temperature; rather, the system acquires the reservoir's
level-occupation-ratio.
| arxiv topic:cond-mat.stat-mech quant-ph |
arxiv_dataset-28011108.2062 | Bundling dynamics regulates the active mechanics and transport in carbon
nanotube networks
cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.soft
High-density carbon nanotube networks (CNNs) continue to attract interest as
active elements in nanoelectronic devices, nanoelectromechanical systems (NEMS)
and multifunctional nanocomposites. The interplay between the network
nanostructure and the its properties is crucial, yet current understanding
remains limited to the passive response. Here, we employ a novel superstructure
consisting of millimeter-long vertically aligned singe walled carbon nanotubes
(SWCNTs) sandwiched between polydimethylsiloxane (PDMS) layers to quantify the
effect of two classes of mechanical stimuli, film densification and stretching,
on the electronic and thermal transport across the network. The network deforms
easily with increase in electrical and thermal conductivities suggestive of
floppy yet highly reconfigurable network. Insight from atomistically informed
coarse-grained simulations uncover an interplay between the extent of lateral
assembly of the bundles, modulated by surface zipping/unzipping, and the
elastic energy associated with the bent conformations of the nanotubes/bundles.
During densification, the network becomes highly interconnected yet we observe
a modest increase in bundling primarily due to the reduced spacing between the
SWCNTs. The stretching, on the other hand, is characterized by an initial
debundling regime as the strain accommodation occurs via unzipping of the
branched interconnects, followed by rapid re-bundling as the strain transfers
to the increasingly aligned bundles. In both cases, the increase in the
electrical and thermal conductivity is primarily due to the increase in bundle
size; the changes in network connectivity have a minor effect on the transport.
Our results have broad implications for filamentous networks of inorganic
nanoassemblies composed of interacting tubes, wires and ribbons/belts.
| arxiv topic:cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.soft |
arxiv_dataset-28021108.2162 | Partner selection in indoor-to-outdoor cooperative networks: an
experimental study
cs.NI
In this paper, we develop a partner selection protocol for enhancing the
network lifetime in cooperative wireless networks. The case-study is the
cooperative relayed transmission from fixed indoor nodes to a common outdoor
access point. A stochastic bivariate model for the spatial distribution of the
fading parameters that govern the link performance, namely the Rician K-factor
and the path-loss, is proposed and validated by means of real channel
measurements. The partner selection protocol is based on the real-time
estimation of a function of these fading parameters, i.e., the coding gain. To
reduce the complexity of the link quality assessment, a Bayesian approach is
proposed that uses the site-specific bivariate model as a-priori information
for the coding gain estimation. This link quality estimator allows network
lifetime gains almost as if all K-factor values were known. Furthermore, it
suits IEEE 802.15.4 compliant networks as it efficiently exploits the
information acquired from the receiver signal strength indicator. Extensive
numerical results highlight the trade-off between complexity, robustness to
model mismatches and network lifetime performance. We show for instance that
infrequent updates of the site-specific model through K-factor estimation over
a subset of links are sufficient to at least double the network lifetime with
respect to existing algorithms based on path loss information only.
| arxiv topic:cs.NI |
arxiv_dataset-28031108.2262 | On the Hochschild and cyclic (co)homology of rapid decay group algebras
math.KT math.GR
We show that the technical condition of solvable conjugacy bound, introduced
in \cite{JOR1}, can be removed without affecting the main results of that
paper. The result is a Burghelea-type description of the summands
$HH_*^t(\BG)_{<x>}$ and $HC_*^t(\BG)_{<x>}$ for any bounding class $\B$,
discrete group with word-length $(G,L)$ and conjugacy class $<x>\in <G>$. We
use this description to prove the conjecture $\B$-SrBC of \cite{JOR1} for a
class of groups that goes well beyond the cases considered in that paper. In
particular, we show that the conjecture $\ell^1$-SrBC (the Strong Bass
Conjecture for the topological $K$-theory of $\ell^1(G)$) is true for all
semihyperbolic groups which satisfy SrBC, a statement consistent with the
rationalized Bost conjecture for such groups.
| arxiv topic:math.KT math.GR |
arxiv_dataset-28041108.2362 | Quantum criticality near the upper critical field of Ce$_2$PdIn$_8$
cond-mat.str-el
We report low-temperature specific heat measurements in magnetic fields up to
12 T applied parallel and perpendicular to the tetragonal c-axis of the heavy
fermion superconductor Ce$_2$PdIn$_8$. In contrast to its quasi-two-dimensional
(2D) relative CeCoIn$_5$, the system displays an almost isotropic upper
critical field. While there is no indication for a FFLO phase in
Ce$_2$PdIn$_8$, the data suggest a smeared weak first-order superconducting
transition close to $H_{c2}\approx 2$ T. The normal state electronic specific
heat coefficient displays logarithmically divergent behavior, comparable to
CeCoIn$_5$ and in agreement with 2D quantum criticality of spin-density-wave
type.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-28051108.2462 | Enhanced public key security for the McEliece cryptosystem
cs.IT cs.CR math.IT
This paper studies a variant of the McEliece cryptosystem able to ensure that
the code used as the public key is no longer permutation-equivalent to the
secret code. This increases the security level of the public key, thus opening
the way for reconsidering the adoption of classical families of codes, like
Reed-Solomon codes, that have been longly excluded from the McEliece
cryptosystem for security reasons. It is well known that codes of these classes
are able to yield a reduction in the key size or, equivalently, an increased
level of security against information set decoding; so, these are the main
advantages of the proposed solution. We also describe possible vulnerabilities
and attacks related to the considered system, and show what design choices are
best suited to avoid them.
| arxiv topic:cs.IT cs.CR math.IT |
arxiv_dataset-28061108.2562 | The transversality conditions in infinite horizon problems and the
stability of adjoint variable
math.OC cs.SY
This paper investigates the necessary conditions of optimality for uni-
formly overtaking optimal control on infinite horizon with free right endpoint.
Clarke's form of the Pontryagin Maximum Principle is proved without the as-
sumption on boundedness of total variation of adjoint variable. The
transversality condition for adjoint variable is shown to become necessary if
the adjoint variable is partially Lyapunov stable. The modifications of this
condition are proposed for the case of unbounded adjoint variable. The
Cauchy-type formula for the adjoint variable proposed by S. M. Aseev and A. V.
Kryazhimskii is shown to complement relations of the Pontryagin Maximum
Principle up to the complete set of necessary conditions of optimality if the
improper integral in the formula converges conditionally and continuously
depends on the original position. The results are extended to an unbounded
objective functional (described by a non- convergent improper integral),
unbounded constraint on the control, and uniformly sporadically catching up
optimal control.
| arxiv topic:math.OC cs.SY |
arxiv_dataset-28071108.2662 | XMM-Newton observations of the dwarf nova RU Peg in quiescence: Probe of
the boundary layer
astro-ph.SR
We present an analysis of X-ray and UV data obtained with the XMM-Newton
Observatory of the long period dwarf nova RU Peg. RU Peg contains a massive
white dwarf, possibly the hottest white dwarf in a dwarf nova, it has a low
inclination, thus optimally exposing its X-ray emitting boundary layer, and has
an excellent trigonometric parallax distance. We modeled the X-ray data using
XSPEC assuming a multi-temperature plasma emission model built from the MEKAL
code. We obtained a maximum temperature of 31.7 keV, based on the EPIC MOS1, 2
and pn data, indicating that RU Peg has an X-ray spectrum harder than most
dwarf novae, except U Gem. This result is consistent with and indirectly
confirms the large mass of the white dwarf in RU Peg. The X-ray luminosity we
computed corresponds to a boundary layer luminosity for a mass accretion rate
of 2.E-11 Msun/yr (assuming Mwd=1.3Msun), in agreement with an expected
quiescent accretion rate. The modeling of the O VIII emission line at 19A as
observed by the RGS implies a projected stellar rotational velocity of 695
km/s, i.e. the line is emitted from material rotating at about 936-1245 km/s
(for i about 34-48deg) or about 1/6 of the Keplerian speed; this velocity is
much larger than the rotation speed of the white dwarf inferred from the FUSE
spectrum. Cross-correlation analysis yielded an undelayed component and a
delayed component of 116 +/- 17 sec where the X-ray variations/fluctuations
lagged the UV variations. This indicates that the UV fluctuations in the inner
disk are propagated into the X-ray emitting region in about 116 sec. The
undelayed component may be related to irradiation effects.
| arxiv topic:astro-ph.SR |
arxiv_dataset-28081108.2762 | Identity for the DFT correlation functional
cond-mat.mtrl-sci
It is shown that the electron density functional correlation functional
satisfies an equation that links the N-electron and (N-1)-electron densities of
the same adiabatically scaled Hamiltonian of the interacting electron system.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-28091108.2862 | A model of $\bar{B}^0\to D^{*+}\omega\pi^-$ decay
hep-ph
We suggest a parameterization of the matrix element for $\bar{B}^0\to
D^{*+}\omega\pi^-$ decay using kinematic variables convenient for experimental
analysis. The contributions of intermediate $\omega\pi$- and $D^{**}$-states up
to spin 3 have been taken into account. The angular distributions for each
discussed hypothesis have been obtained and analysed using Monte-Carlo
simulation.
| arxiv topic:hep-ph |
arxiv_dataset-28101108.2962 | Three-wave interactions and spatio-temporal chaos
nlin.PS physics.flu-dyn
Three-wave interactions form the basis of our understanding of many pattern
forming systems because they encapsulate the most basic nonlinear interactions.
In problems with two comparable length scales, it is possible for two waves of
the shorter wavelength to interact with one wave of the longer, as well as for
two waves of the longer wavelength to interact with one wave of the shorter.
Consideration of both types of three-wave interactions can generically explain
the presence of complex patterns and spatio-temporal chaos. Two length scales
arise naturally in the Faraday wave experiment with multi-frequency forcing,
and our results enable some previously unexplained experimental observations of
spatio-temporal chaos to be interpreted in a new light. Our predictions are
illustrated with numerical simulations of a model partial differential
equation.
| arxiv topic:nlin.PS physics.flu-dyn |
arxiv_dataset-28111108.3062 | Observation of sub-Bragg diffraction of waves in crystals
physics.optics
We investigate the diffraction conditions and associated formation of
stopgaps for waves in crystals with different Bravais lattices. We identify a
prominent stopgap in high-symmetry directions that occurs at a frequency below
the ubiquitous first-order Bragg condition. This sub-Bragg diffraction
condition is demonstrated by reflectance spectroscopy on two-dimensional
photonic crystals with a centred rectangular lattice, revealing prominent
diffraction peaks for both the sub-Bragg and first-order Bragg condition. These
results have implications for wave propagation in 2 of the 5 two-dimensional
Bravais lattices and 7 out of 14 three-dimensional Bravais lattices, such as
centred rectangular, triangular, hexagonal and body-centred cubic.
| arxiv topic:physics.optics |
arxiv_dataset-28121108.3162 | On the genesis and evolution of Integrated Quantum Optics
quant-ph
Applications of Integrated Optics to quantum sources, detectors, interfaces,
memories and linear optical quantum computing are described in this review. By
their inherent compactness, efficiencies, and interconnectability, many of the
demonstrated individual devices can clearly serve as building blocks for more
complex quantum systems, that could also profit from the incorporation of other
guided wave technologies.
| arxiv topic:quant-ph |
arxiv_dataset-28131108.3262 | Bayesian Inference in Nonparametric Dynamic State-Space Models
stat.ME
We introduce state-space models where the functionals of the observational
and the evolutionary equations are unknown, and treated as random functions
evolving with time. Thus, our model is nonparametric and generalizes the
traditional parametric state-space models. This random function approach also
frees us from the restrictive assumption that the functional forms, although
time-dependent, are of fixed forms. The traditional approach of assuming known,
parametric functional forms is questionable, particularly in state-space
models, since the validation of the assumptions require data on both the
observed time series and the latent states; however, data on the latter are not
available in state-space models.
We specify Gaussian processes as priors of the random functions and exploit
the "look-up table approach" of \ctn{Bhattacharya07} to efficiently handle the
dynamic structure of the model. We consider both univariate and multivariate
situations, using the Markov chain Monte Carlo (MCMC) approach for studying the
posterior distributions of interest. In the case of challenging multivariate
situations we demonstrate that the newly developed Transformation-based MCMC
(TMCMC) of \ctn{Dutta11} provides interesting and efficient alternatives to the
usual proposal distributions. We illustrate our methods with a challenging
multivariate simulated data set, where the true observational and the
evolutionary equations are highly non-linear, and treated as unknown. The
results we obtain are quite encouraging. Moreover, using our Gaussian process
approach we analysed a real data set, which has also been analysed by
\ctn{Shumway82} and \ctn{Carlin92} using the linearity assumption. Our analyses
show that towards the end of the time series, the linearity assumption of the
previous authors breaks down.
| arxiv topic:stat.ME |
arxiv_dataset-28141108.3362 | Cosmic Ray Protons Illuminate Dark Matter Axions
hep-ph astro-ph.HE
Cosmic ray protons propagating in a spatially-homogeneous but time-dependent
field of axions or axion-like particles (ALPs) emit photons in a way that is
reminiscent of Cherenkov radiation by charged particles in a preferred
background. We compute the emission rate and energy spectrum of the photons,
and discuss the possibility of their detection using the Square Kilometre Array
which is currently under construction. In the case of a non-detection,
constraints can be placed on the parameter space of ALPs whose mass lie between
$10^{-7}$eV and $10^{-5}$ eV under the assumption that they are the primary
constituent of dark matter.
| arxiv topic:hep-ph astro-ph.HE |
arxiv_dataset-28151108.3462 | A Multiagent Simulation for Traffic Flow Management with Evolutionary
Optimization
cs.MA nlin.AO
A traffic flow is one of the main transportation issues in nowadays
industrialized agglomerations. Configuration of traffic lights is among the key
aspects in traffic flow management. This paper proposes an evolutionary
optimization tool that utilizes multiagent simulator in order to obtain
accurate model. Even though more detailed studies are still necessary, a
preliminary research gives an expectation for promising results.
| arxiv topic:cs.MA nlin.AO |
arxiv_dataset-28161108.3562 | Possibility of Skyrmion Superconductivity in Doped Antiferromagnet
K$_2$Fe$_4$Se$_5$
cond-mat.supr-con hep-th
Intercalated Fe chalcogenide K$_2$Fe$_4$Se$_5$ family exhibits high Tc
($\sim$ 30 K) superconductivity and spin-8 high T$_{\rm N}$ ($\sim$ 560 K)
antiferromagnetism (AFM). We present a model Hamiltonian and suggest
\textit{Skyrmion superconductivity}. A doped electron creates an orbitally non
degenerate S=7\half state in a F$_4$Se$_9$ cluster and moves in a single
correlated band, exchange coupled to a robust S=8 AFM order. Skyrmion, a
topological excitation of 2 dimensional AFM order acquires an \textit{induced
charge -2e} through a quantum anomaly and becomes a Cooper pair.
Superconductivity emerges for a range of doping. Fluctuating superconductivity,
arising from preformed Cooper pairs (stable Skyrmions), around room
temperatures is predicted. We offer hope for higher Tc's in large-S Mott
insulators.
| arxiv topic:cond-mat.supr-con hep-th |
arxiv_dataset-28171108.3662 | The Outer Disks of Early-Type Galaxies. II. Surface-Brightness Profiles
of Unbarred Galaxies and Trends with Hubble Type
astro-ph.CO
We present azimuthally averaged radial profiles of R-band surface brightness
for a complete sample of 47 early-type, unbarred galaxies, as a complement to
our previous study of early-type barred galaxies. Following very careful sky
subtraction, the profiles can typically be determined down to brightness levels
well below 27 mag arcsec^{-2} and in the best cases below 28 mag arcsec^{-2}.
We classified the profiles according to the scheme used previously for the
barred sample: Type I profiles are single unbroken exponential radial declines
in brightness; Type II profiles ("truncations") have an inner shallow slope
(usually exponential) which changes at a well defined break radius to a steeper
exponential; and Type III profiles ("antitruncations") have an inner
exponential that is steeper, giving way to a shallower outer (usually
exponential) decline.
By combining these profiles with previous studies, we can make the first
clear statements about the trends of outer-disk profile types along the Hubble
sequence (including both barred and unbarred galaxies), and their global
frequencies. We find that Type I profiles are most frequent in early-type
disks, decreasing from one-third of all S0--Sa disks to barely 10% of the
latest type spirals. Conversely, Type II profiles (truncations) increase in
frequency with Hubble type, from only ~25% of S0 galaxies to ~80% of Sd--Sm
spirals. Overall, the fractions of Type I, II, and III profiles for all disk
galaxies (Hubble types S0--Sm) are: 21%, 50%, and 38%, respectively; this
includes galaxies (~8% of the total) with composite Type II+III profiles
(counted twice).
Finally, we note the presence of bars in ten galaxies previously classified
(optically) as "unbarred". This suggests that ~20% of optically unbarred
galaxies are actually barred; the bars in such cases can be weak, obscured by
dust, or so large as to be mistaken for the main disk
| arxiv topic:astro-ph.CO |
arxiv_dataset-28181108.3762 | Higgs mass and inflation
hep-ph astro-ph.CO
We show that the standard-model Higgs boson mass m_h is correlated with the
spectral index of density perturbation n_s in the inflation scenario with the
inflaton being identified with the B-L Higgs boson. The Higgs boson mass ranges
from m_h ~ 120GeV to 140GeV for n_s ~ 0.95 - 0.96. In particular, as n_s
approaches to 0.96, the Higgs mass is predicted to be in the range of 125GeV to
140GeV in the case of relatively light gauginos, and 120GeV to 135GeV in the
case where all SUSY particle masses are of the same order. This will be tested
soon by the LHC experiment and the Planck satellite. The relation is due to the
PeV-scale supersymmetry required by the inflationary dynamics. We also comment
on the cosmological implications of our scenario such as non-thermal
leptogenesis and dark matter.
| arxiv topic:hep-ph astro-ph.CO |
arxiv_dataset-28191108.3862 | Topological liquids and valence cluster states in two-dimensional SU(N)
magnets
cond-mat.str-el cond-mat.quant-gas
We study the zero temperature phase diagram of a class of two-dimensional
SU(N) antiferromagnets. These models are characterized by having the same type
of SU(N) spin placed at each site of the lattice, and share the property that,
in general, more than two spins must be combined to form a singlet. An
important motivation to study these systems is that they may be realized
naturally in Mott insulators of alkaline earth atoms placed on optical
lattices; indeed, such Mott insulators have already been obtained
experimentally, although the temperatures are still high compared to the
magnetic exchange energy. We study these antiferromagnets in a large-N limit,
finding a variety of ground states. Some of the models studied here have a
valence bond solid ground state, as was found in prior studies, yet we find
that many others have a richer variety of ground states. Focusing on the
two-dimensional square lattice, in addition to valence cluster states (which
are analogous to valence bond states), we find both Abelian and non-Abelian
chiral spin liquid ground states, which are magnetic counterparts of the
fractional quantum Hall effect. We also find a "doubled" chiral spin liquid
ground state that preserves time reversal symmetry. These results are based on
a combination of rigorous lower bounds on the large-N ground state energy, and
a systematic numerical ground state search. We conclude by discussing whether
experimentally relevant SU(N) antiferromagnets -- away from the large-N limit
-- may be chiral spin liquids.
| arxiv topic:cond-mat.str-el cond-mat.quant-gas |
arxiv_dataset-28201108.3962 | The Instabilities of Bianchi Type IX Einstein Static Universes
gr-qc astro-ph.CO hep-th
We investigate the stability of the Einstein static universe as a non-LRS
Bianchi type IX solution of the Einstein equations in the presence of both
non-tilted and tilted fluids. We find that the static universe is unstable to
homogeneous perturbations of Bianchi type IX to the future and the past.
| arxiv topic:gr-qc astro-ph.CO hep-th |
arxiv_dataset-28211108.4062 | Estimate of CP Violation for the LBNE Project and $\delta_{CP}
hep-ph
Measurements of CP violation (CPV) and the basic $\delta_{CP}$ parameter are
the goals of the LBNE Project, which is being planned. Using the expected
energy and baseline parameters for the LBNE Project, CPV and the dependence of
CPV on $\delta_{CP}$ are estimated, to help in the planning of this project.
| arxiv topic:hep-ph |
arxiv_dataset-28221108.4162 | Time-Dependent Behavior of Lyman$\alpha$ Photon Transfer in High
Redshift Optically Thick Medium
astro-ph.CO
With Monte Carlo simulation method, we investigate the time dependent
behavior of Ly$\alpha$ photon transfer in optically thick medium of the
concordance $\Lambda$CDM universe. At high redshift, the Ly$\alpha$ photon
escaping from optically thick medium has a time scale as long as the age of the
luminous object, or even comparable to the age of the universe. In this case,
time-independent, or stationary solutions of the Ly$\alpha$ photon transfer
with resonant scattering will overlook important features of the escaped
Ly$\alpha$ photons in physical and frequency spaces. More seriously, the
expansion of the universe leads to that the time-independent solutions of the
Ly$\alpha$ photon transfer may not exist. We show that time-dependent solutions
sometimes are essential for understanding the Ly$\alpha$ emission and
absorption at high redshifts. For Ly\alpha photons from sources at redshift
1+z=10 and being surrounded by neutral hydrogen IGM of the $\Lambda$CDM
universe, the escape coefficient is found to be always less, or much less than
one, regardless of the age or life time of the sources. Under such environment,
we also find that even when the Ly$\alpha$ photon luminosity of the sources is
stable, the mean surface brightness is gradually increasing in the first 10^6
years, and then decreasing with a power law of time, but never approaches a
stable, time-independent state. That is, all 1+z=10 sources in a neutral Hubble
expanding IGM with Ly$\alpha$ luminosity L have their maximum of mean surface
brightness ~ 10^{-21}(L/(10^{43}erg/s)) erg s^{-1} cm^{-2} arcsec^{-2} at the
age of about 10^6 years. The time-dependent effects on the red damping wing
profile are also addressed.
| arxiv topic:astro-ph.CO |
arxiv_dataset-28231108.4262 | An Optimal Odd Unimodular Lattice in Dimension 72
math.CO math.NT
It is shown that if there is an extremal even unimodular lattice in dimension
72, then there is an optimal odd unimodular lattice in that dimension. Hence,
the first example of an optimal odd unimodular lattice in dimension 72 is
constructed from the extremal even unimodular lattice which has been recently
found by G. Nebe.
| arxiv topic:math.CO math.NT |
arxiv_dataset-28241108.4362 | CFT Duals of Black Rings With Higher Derivative Terms
hep-th
We study possible CFT duals of supersymmetric five dimensional black rings in
the presence of supersymmetric higher derivative corrections to the N=2
supergravity action. A Virasoro algebra associated to an asymptotic symmetry
group of solutions is defined by using the Kerr/CFT approach. We find the
central charge and compute the microscopic entropy which is in precise
agreement with the macroscopic entropy. Although apparently related to a
different aspect of the near-horizon geometry and a different Virasoro algebra,
we find that the c-extremization method leads to the same central charge and
microscopic entropy computed in the Kerr/CFT approach. The relationship between
these two point of view is clarified by relating the geometry to a self-dual
orbifold of AdS3.
| arxiv topic:hep-th |
arxiv_dataset-28251108.4462 | Gauge-Higgs Unification In Spontaneously Created Fuzzy Extra Dimensions
hep-ph hep-th
We propose gauge-Higgs unification in fuzzy extra dimensions as a possible
solution to the Higgs naturalness problem. In our approach, the fuzzy extra
dimensions are created spontaneously as a vacuum solution of certain
four-dimensional gauge theory. As an example, we construct a model which has a
fuzzy torus as its vacuum. The Higgs field in our model is associated with the
Wilson loop wrapped on the fuzzy torus. We show that the quadratic divergence
in the mass of the Higgs field in the one-loop effective potential is absent.
We then argue based on symmetries that the quantum corrections to the Higgs
mass is suppressed including all loop contributions. We also consider a
realization on the worldvolume theory of D3-branes probing $C^3/(Z_N \times
Z_N)$ orbifold with discrete torsion.
| arxiv topic:hep-ph hep-th |
arxiv_dataset-28261108.4562 | Asymptotically Lifshitz Brane-World Black Holes
hep-th gr-qc
We study the gravity dual of a Lifshitz field theory in the context of a RSII
brane-world scenario, taking into account the effects of the extra dimension
through the contribution of the electric part of the Weyl tensor. We study the
thermodynamical behavior of such asymptotically Lifshitz black holes. It is
shown that the entropy imposes the critical exponent $z$ to be bounded from
above. This maximum value of $z$ corresponds to a positive infinite entropy as
long as the temperature is kept positive. The stability and phase transition
for different spatial topologies are also discussed.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-28271108.4662 | On Legendre Multiplier Sequences
math.CV
In this paper we give a complete characterization of linear, quadratic, and
geometric Legendre multiplier sequences. We also prove that all Legendre
multiplier sequences must be Hermite multiplier sequences, and describe the
relationship between the Legendre and generalized Laguerre multiplier
sequences. We conclude with a list of open questions for further research.
| arxiv topic:math.CV |
arxiv_dataset-28281108.4762 | Investigations on the properties of the arithmetic derivative
math.NT
We investigate the properties of arithmetic differentiation, an attempt to
adapt the notion of differentiation to the integers by preserving the Leibniz
rule, (ab)' = a'b + ab'. This has proved to be a very rich topic with many
different aspects and implications to other fields of mathematics and
specifically to various unproven conjectures in additive prime number theory.
Our paper consists of a self-contaited introduction to the topic, along with a
couple of new theorems, several of them related to arithmetic differentiation
of rational numbers, a topic almost unexplored until now.
| arxiv topic:math.NT |
arxiv_dataset-28291108.4862 | Correlations and Fluctuations in the Initial State of high energy Heavy
Ion Collisions
nucl-th
Initial states of high energy heavy ion collisions are studied using a dipole
model through the DIPSY event generator that dynamically includes saturation
together with the fluctuations and correlations of the BFKL cascade. The
eccentricities of first up to fourth moment are calculated at RHIC and LHC.
Predictions are made for correlations and fluctuations in rapidity of the
eccentricities, and conventional theoretical approximations are tested. A large
set of initial state Au-Au, Cu-Au and Pb-Pb collisions have been generated and
are published online.
| arxiv topic:nucl-th |
arxiv_dataset-28301108.4962 | Semi-global symplectic invariants of the spherical pendulum
math.DS math.SG nlin.SI physics.class-ph
We explicitly compute the semi-global symplectic invariants near the
focus-focus point of the spherical pendulum. A modified Birkhoff normal form
procedure is presented to compute the expansion of the Hamiltonian near the
unstable equilibrium point in Eliasson-variables. Combining this with explicit
formulas for the action we find the semi-global symplectic invariants near the
focus-focus point introduced by Vu Ngoc 2003. We also show that the Birkhoff
normal form is the inverse of a complete elliptic integral over a vanishing
cycle. To our knowledge this is the first time that semi-global symplectic
invariants near a focus-focus point have been computed explicitly. We close
with some remarks about the pendulum, for which the invariants can be related
to theta functions in a beautiful way.
| arxiv topic:math.DS math.SG nlin.SI physics.class-ph |
arxiv_dataset-28311108.5062 | A Non-Standard Semantics for Kahn Networks in Continuous Time
cs.PL math.CT
In a seminal article, Kahn has introduced the notion of process network and
given a semantics for those using Scott domains whose elements are (possibly
infinite) sequences of values. This model has since then become a standard tool
for studying distributed asynchronous computations. From the beginning, process
networks have been drawn as particular graphs, but this syntax is never
formalized. We take the opportunity to clarify it by giving a precise
definition of these graphs, that we call nets. The resulting category is shown
to be a fixpoint category, i.e. a cartesian category which is traced wrt the
monoidal structure given by the product, and interestingly this structure
characterizes the category: we show that it is the free fixpoint category
containing a given set of morphisms, thus providing a complete axiomatics that
models of process networks should satisfy. We then use these tools to build a
model of networks in which data vary over a continuous time, in order to
elaborate on the idea that process networks should also be able to encompass
computational models such as hybrid systems or electric circuits. We relate
this model to Kahn's semantics by introducing a third model of networks based
on non-standard analysis, whose elements form an internal complete partial
order for which many properties of standard domains can be reformulated. The
use of hyperreals in this model allows it to formally consider the notion of
infinitesimal, and thus to make a bridge between discrete and continuous time:
time is "discrete", but the duration between two instants is infinitesimal.
Finally, we give some examples of uses of the model by describing some networks
implementing common constructions in analysis.
| arxiv topic:cs.PL math.CT |
arxiv_dataset-28321108.5162 | New Initiatives on RR Lyrae Chemical Compositions
astro-ph.SR
The serendipitous discovery by Preston and colleagues of the
neutron-capture-enhanced RR Lyrae variable star TY Gru (a.k.a. CS 22881-071 in
the "HK" survey of very metal-poor halo stars) has resulted in a growing set of
initiatives on the chemical compositions of RR Lyrae stars and their
application to broader topics in Galactic halo structure. Here we summarize the
main aspects of our work on TY Gru, including a new discussion of our search
for possible orbital motion of this star around a putative unseen companion.
Then we describe a few of the results of a newly-completed intensive
spectroscopic investigation of 10 additional field RR Lyr stars. We finish by
outlining current projects that seek to contrast the atmospheres and chemical
compositions of RRc stars with those of the RRab stars, and that employ a much
larger RRab sample in a chemo-dynamical study of Galactic halo RR Lyr.
| arxiv topic:astro-ph.SR |
arxiv_dataset-28331108.5262 | On least favorable configurations for step-up-down tests
stat.ME
This paper investigates an open issue related to false discovery rate (FDR)
control of step-up-down (SUD) multiple testing procedures. It has been
established in earlier literature that for this type of procedure, under some
broad conditions, and in an asymptotical sense, the FDR is maximum when the
signal strength under the alternative is maximum. In other words, so-called
"Dirac uniform configurations" are asymptotically {\em least favorable} in this
setting. It is known that this property also holds in a non-asymptotical sense
(for any finite number of hypotheses), for the two extreme versions of SUD
procedures, namely step-up and step-down (with extra conditions for the
step-down case). It is therefore very natural to conjecture that this
non-asymptotical {\em least favorable configuration} property could more
generally be true for all "intermediate" forms of SUD procedures. We prove that
this is, somewhat surprisingly, not the case. The argument is based on the
exact calculations proposed earlier by Roquain and Villers (2011), that we
extend here by generalizing Steck's recursion to the case of two populations.
Secondly, we quantify the magnitude of this phenomenon by providing a
nonasymptotic upper-bound and explicit vanishing rates as a function of the
total number of hypotheses.
| arxiv topic:stat.ME |
arxiv_dataset-28341108.5362 | Model independent search for new phenomena in pp(bar) collisions at
sqrt(s) =1.96 TeV
hep-ex
We describe a model independent search for physics beyond the standard model
in lepton final states. We examine 117 final states using 1.1 fb$^{-1}$ of $p
\bar{p}$ collisions data at $\sqrt{s} = 1.96$ TeV collected with the D0
detector. We conclude that all observed discrepancies between data and model
can be attributed to uncertainties in the standard model background modeling,
and hence we do not see any evidence for physics beyond the standard model.
| arxiv topic:hep-ex |
arxiv_dataset-28351108.5462 | Stability of peak solutions of a non-linear transport equation on the
circle
math.AP math.DS
We analyze the pattern forming ability and pattern stability for a
one-dimensional non-linear transport-diffusion equation on the circle. We show
that the trivial steady state is stable when diffusion is sufficiently strong.
In the limit for vanishing diffusion, linear combinations of delta peaks can be
stationary solutions; we study their stability properties. Finally, we present
numerical examples exhibiting a variety of behaviors.
| arxiv topic:math.AP math.DS |
arxiv_dataset-28361108.5562 | Analytical description of the Coherent State Model for near vibrational
and well deformed nuclei
nucl-th
Analytical formulas for the excitation energies as well as for the electric
quadrupole reduced transition probabilities in the ground, beta and gamma bands
were derived within the coherent state model for the near vibrational and well
deformed nuclei. Numerical calculations were performed for 42 nuclei exhibiting
various symmetries and therefore with specific properties. Comparison of the
calculation results with the corresponding experimental data shows a good
agreement. The parameters involved in the proposed model satisfy evident
regularities being interpolated by smooth curves. Few of them, which fall out
of the curves, are interpreted as signatures for a critical point in a specific
phase transition. This is actually supported also by the figures showing the
excitation energy dependence on the angular momentum. The formulas provided for
energies and B(E2) values are very simple, being written in a compact form, and
therefore easy to be handled to explain the new experimental data.
| arxiv topic:nucl-th |
arxiv_dataset-28371108.5662 | Jet Modification in a Brick of QGP Matter
hep-ph
We have implemented the LPM effect into a microscopic transport model with
partonic degrees of freedom by following the algorithm of Zapp & Wiedemann. The
Landau-Pomeranchuk-Migdal (LPM) effect is a quantum interference process that
modifies the emission of radiation in the presence of a dense medium. In QCD
this results in a quadratic length dependence for radiative energy loss. This
is an important effect for the modification of jets by their passage through
the QGP.
We verify the leading parton energy loss in the model against the leading
order Baier-Dokshitzer-Mueller-Peigne-Schiff-Zakharov (BDMPS-Z) result.
We apply our model to the recent observations of the modification of di-jets
at the LHC.
| arxiv topic:hep-ph |
arxiv_dataset-28381108.5762 | Superconductivity of Bi Confined in an Opal Host
cond-mat.supr-con
Superconductivity is observed in a composite of rhombohedral crystalline
bismuth nanoparticles imbedded in an insulating porous opal host via electrical
transport and AC magnetic susceptibility. The onset of superconductivity in
this system occurs in two steps, with upper critical temperature Tc,U = 4.1 K
and lower transition temperature of Tc,L = 0.7 K, which we attribute to the
granular nature of the composite. The transition at Tc,U is observed to split
into two transitions with the application of a magnetic field, and has upper
critical field extrapolated to T = 0 K of Hc2,1(0) = 0.7 T and Hc2,2(0) = 1.0
T, corresponding to coherence lengths of xi1(0) = 21 nm and xi2(0) = 18 nm,
respectively. We suggest that because of the lack of bulk-like states in the Bi
nanoparticles due to confinement effects, superconductivity originates from
surface states arising from Rashba spin-orbit scattering at the interface. This
prospect suggests that nanostructured Bi may be an interesting system to search
for Majorana fermions.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-28391108.5862 | Homology of powers of ideals: Artin--Rees numbers of syzygies and the
Golod property
math.AC
For an ideal I in a regular local ring (R,m)$ with residue class field K =
R/m or a standard graded K-algebra R we show that for k >> 0
--> the Artin--Rees number of the syzygy modules of I^k as submodules of the
free modules from a free resolution is constant, and thereby present the
Artin-Rees number as a proper replacement of regularity in the local situation,
--> the ring R/I^k is Golod, its Poincer{\'e}-Betti series is rational and
the Betti numbers of the free resolution of K over R/I^k are polynomials in k
of a specific degree.
The first result is an extension of work of Kodiyalam and Cutkosky, Herzog &
Trung on the regularity of I^k for k >> 0 from the graded situation to the
local situation. The polynomiality consequence of the second result is an
analog of work by Kodiyalam on the behavior of Betti numbers of the minimal
free resolution of R/I^k over R.
| arxiv topic:math.AC |
arxiv_dataset-28401108.5962 | Enhanced shot noise in asymmetric interacting two level systems
cond-mat.mes-hall cond-mat.str-el
We study a model of two interacting levels that are attached to two
electronic leads, where one of the levels is attached very weakly to the leads.
We use rate equations method to calculate the average current and the noise of
electrons transmitted through the two levels. We show that the shot noise is
enhanced due to the interactions and that the Fano factor depends on the
properties of the couplings between the levels and the leads. We study both
sequential tunneling and cotunneling processes and show that there is a range
of parameters in which the cotunneling processes affect the noise
significantly, even though most of the current is carried by sequential
tunneling processes.
| arxiv topic:cond-mat.mes-hall cond-mat.str-el |
arxiv_dataset-28411108.6062 | Prediction of lethal and synthetically lethal knock-outs in regulatory
networks
q-bio.MN
The complex interactions involved in regulation of a cell's function are
captured by its interaction graph. More often than not, detailed knowledge
about enhancing or suppressive regulatory influences and cooperative effects is
lacking and merely the presence or absence of directed interactions is known.
Here we investigate to which extent such reduced information allows to forecast
the effect of a knock-out or a combination of knock-outs. Specifically we ask
in how far the lethality of eliminating nodes may be predicted by their network
centrality, such as degree and betweenness, without knowing the function of the
system. The function is taken as the ability to reproduce a fixed point under a
discrete Boolean dynamics. We investigate two types of stochastically generated
networks: fully random networks and structures grown with a mechanism of node
duplication and subsequent divergence of interactions. On all networks we find
that the out-degree is a good predictor of the lethality of a single node
knock-out. For knock-outs of node pairs, the fraction of successors shared
between the two knocked-out nodes (out-overlap) is a good predictor of
synthetic lethality. Out-degree and out-overlap are locally defined and
computationally simple centrality measures that provide a predictive power
close to the optimal predictor.
| arxiv topic:q-bio.MN |
arxiv_dataset-28421108.6162 | Optical diode based on the one-way light-speed anisotropy
physics.optics
We report that a triangular Fabry-Perot resonator filled with a parity-odd
linear anisotropic medium exhibiting the one-way light speed anisotropy acts as
a perfect diode. A Linear crystal such as the nematic liquid crystals whose
molecular structures break parity can exhibit the one-way light speed
anisotropy. The one-way light speed anisotropy also can be induced in a
non-linear medium in the presence of constant electric and magnetic field
strengths.
| arxiv topic:physics.optics |
arxiv_dataset-28431108.6262 | Statistics and scaling properties of temperature field in symmetrical
non-Oberbeck-Boussinesq turbulent convection
physics.flu-dyn nlin.CD
The influence of symmetrical non-Oberbeck-Boussinesq (SNOB) effect on
statistical and scaling properties of temperature field in turbulent convection
is investigated experimentally in $SF_{6}$ in the vicinity of its gas-liquid
critical point (CP). The main conclusion of the studies is that besides the
strong $Ra$ and $Pr$ dependence of the rms of temperature fluctuations
normalized by the temperature difference across the cell, different from the
Oberbeck-Boussinesq (OB) case of turbulent convection, all rest of statistical
and scaling properties of temperature field discussed in details are the same
as in the OB case.
| arxiv topic:physics.flu-dyn nlin.CD |
arxiv_dataset-28441109.0031 | The minimal 3-3-1 model with only two Higgs triplets
hep-ph
The simplest non-abelian gauge extension of the electroweak standard model,
the $SU(3)_c\otimes SU(3)_L\otimes U(1)_N$, known as 3-3-1 model, has a minimal
version which demands the least possible fermionic content to account for the
whole established phenomenology for the well known particles and interactions.
Nevertheless, in its original form the minimal 3-3-1 model was proposed with a
set of three scalar triplets and one sextet in order to yield the spontaneous
breaking of the gauge symmetry and generate the observed fermion masses. Such a
huge scalar sector turns the task of clearly identifying the physical scalar
spectrum a clumsy labor. It not only adds an obstacle for the development of
its phenomenology but implies a scalar potential plagued with new free coupling
constants. In this work we show that the framework of the minimal 3-3-1 model
can be built with only two scalar triplets, but still triggering the desired
pattern of spontaneous symmetry breaking and generating the correct fermion
masses. We present the exact physical spectrum and also show all the
interactions involving the scalars, obtaining a neat minimal 3-3-1 model far
more suited for phenomenological studies at the current Large Hadron Collider.
| arxiv topic:hep-ph |
arxiv_dataset-28451109.0131 | A note on the computation of geometrically defined relative velocities
gr-qc math.DG
We discuss some aspects about the computation of kinematic, spectroscopic,
Fermi and astrometric relative velocities that are geometrically defined in
general relativity. Mainly, we state that kinematic and spectroscopic relative
velocities only depend on the 4-velocities of the observer and the test
particle, unlike Fermi and astrometric relative velocities, that also depend on
the acceleration of the observer and the corresponding relative position of the
test particle, but only at the event of observation and not around it, as it
would be deduced, in principle, from the definition of these velocities.
Finally, we propose an open problem in general relativity that consists on
finding intrinsic expressions for Fermi and astrometric relative velocities
avoiding terms that involve the evolution of the relative position of the test
particle. For this purpose, the proofs given in this paper can serve as
inspiration.
| arxiv topic:gr-qc math.DG |
arxiv_dataset-28461109.0232 | Quadratic polynomials represented by norm forms
math.NT
The Hasse principle and weak approximation is established for equations of
the shape P(t)=N(x_1,x_2,x_3,x_4), where P is an irreducible quadratic
polynomial in one variable and N is a norm form associated to a quartic
extension of the rationals containing the roots of P. The proof uses analytic
methods.
| arxiv topic:math.NT |
arxiv_dataset-28471109.0332 | Pade approximants for functions with branch points - strong asymptotics
of Nuttall-Stahl polynomials
math.CA
Let f be a germ of an analytic function at infinity that can be analytically
continued along any path in the complex plane deprived of a finite set of
points, f \in\mathcal{A}(\bar{\C} \setminus A), \sharp A <\infty. J. Nuttall
has put forward the important relation between the maximal domain of f where
the function has a single-valued branch and the domain of convergence of the
diagonal Pade approximants for f. The Pade approximants, which are rational
functions and thus single-valued, approximate a holomorphic branch of f in the
domain of their convergence. At the same time most of their poles tend to the
boundary of the domain of convergence and the support of their limiting
distribution models the system of cuts that makes the function f single-valued.
Nuttall has conjectured (and proved for many important special cases) that this
system of cuts has minimal logarithmic capacity among all other systems
converting the function f to a single-valued branch. Thus the domain of
convergence corresponds to the maximal (in the sense of minimal boundary)
domain of single-valued holomorphy for the analytic function f
\in\mathcal{A}(\bar{\C} \setminus A). The complete proof of Nuttall's
conjecture (even in a more general setting where the set A has logarithmic
capacity zero) was obtained by H. Stahl. In this work, we derive strong
asymptotics for the denominators of the diagonal Pade approximants for this
problem in a rather general setting. We assume that A is a finite set of branch
points of f which have the algebraic character and which are placed in a
generic position. The last restriction means that we exclude from our
consideration some degenerated "constellations" of the branch points.
| arxiv topic:math.CA |
arxiv_dataset-28481109.0432 | Indirect Evidence for New Physics at the 10 TeV Scale
hep-ph
We show that the supersymmetric extension of the Standard Model modifies the
structure of the low lying BFKL discrete pomeron states (DPS) which give a
sizable contribution to the gluon structure function in the HERA x and Q2
region. The comparison of the gluon density, determined within DPS with N=1
SUSY, with data favours a supersymmetry scale of the order of 10 TeV. The DPS
method described here could open a new window to the physics beyond the
Standard Model.
| arxiv topic:hep-ph |
arxiv_dataset-28491109.0532 | On Brane Back-Reaction and de Sitter Solutions in Higher-Dimensional
Supergravity
hep-th gr-qc
We argue that the problem of finding lower-dimensional de Sitter solutions to
the classical field equations of higher-dimensional supergravity necessarily
requires understanding the back-reaction of whatever localized objects source
the bulk fields. However, we also find that most of the details of the
back-reacted solutions are not important for determining the lower-dimensional
curvature. We find, in particular, a classically exact expression that, for a
broad class of geometries, directly relates the curvature of the
lower-dimensional geometry to asymptotic properties of various bulk fields near
the sources. Specializing to codimension-two sources, we find that the
contribution involving the asymptotic behaviour of the warp factor (which has a
definite sign for most supergravities and so is usually used to infer a
preference for anti-de Sitter geometries) is precisely canceled by the
contribution of the sources themselves (that are left out in earlier
treatments). We identify which combination of bulk fields survives this
cancelation, and so controls the sign of the lower-dimensional geometry, for
several supergravities in 6, 10 and 11 dimensions. Our results show precisely
why explicit 4D de Sitter solutions to 6D supergravity evade general no-go
theorems. As an application we show that all classical compactifications of
Type IIB supergravity (and F-theory) to 8 dimensions are 8D-flat if they
involve only the metric and the axio-dilaton sourced by codimension-two
sources, extending earlier results to include warped solutions and more general
source properties.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-28501109.0632 | A Phenomenological Theory of the Anomalous Pseudogap Phase in Underdoped
Cuprates
cond-mat.str-el
The theoretical description of the anomalous properties of the pseudogap
phase in the underdoped region of the cuprate phase diagram lags behind the
progress in spectroscopic and other experiments. A phenomenological ansatz,
based on analogies to the approach to Mott localization at weak coupling in
lower dimensional systems, has been proposed by Yang, Rice and Zhang [Phys.
Rev. B 73 (2006),174501]. This ansatz has had success in describing a range of
experiments. The motivation underlying this ansatz is described and the
comparisons to experiment are reviewed. Implications for a more microscopic
theory are discussed together with the relation to theories that start directly
from microscopic strongly coupled Hamiltonians.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-28511109.0732 | Multilingual ontology matching based on Wiktionary data accessible via
SPARQL endpoint
cs.IR
Interoperability is a feature required by the Semantic Web. It is provided by
the ontology matching methods and algorithms. But now ontologies are presented
not only in English, but in other languages as well. It is important to use an
automatic translation for obtaining correct matching pairs in multilingual
ontology matching. The translation into many languages could be based on the
Google Translate API, the Wiktionary database, etc. From the point of view of
the balance of presence of many languages, of manually crafted translations, of
a huge size of a dictionary, the most promising resource is the Wiktionary. It
is a collaborative project working on the same principles as the Wikipedia. The
parser of the Wiktionary was developed and the machine-readable dictionary was
designed. The data of the machine-readable Wiktionary are stored in a
relational database, but with the help of D2R server the database is presented
as an RDF store. Thus, it is possible to get lexicographic information
(definitions, translations, synonyms) from web service using SPARQL requests.
In the case study, the problem entity is a task of multilingual ontology
matching based on Wiktionary data accessible via SPARQL endpoint. Ontology
matching results obtained using Wiktionary were compared with results based on
Google Translate API.
| arxiv topic:cs.IR |
arxiv_dataset-28521109.0832 | The need for speed : Maximizing random walks speed on fixed environments
math.PR
We study nearest neighbor random walks on fixed environments of $\mathbb{Z}$
composed of two point types : $(1/2,1/2)$ and $(p,1-p)$ for $p>1/2$. We show
that for every environment with density of $p$ drifts bounded by $\lambda$ we
have $\limsup_{n\rightarrow\infty}\frac{X_n}{n}\leq (2p-1)\lambda$, where $X_n$
is a random walk on the environment. In addition up to some integer effect the
environment which gives the best speed is given by equally spaced drifts.
| arxiv topic:math.PR |
arxiv_dataset-28531109.0932 | Spatial matter density mapping of the STAGES Abell A901/2 supercluster
field with 3D lensing
astro-ph.CO
We present weak lensing data from the HST/STAGES survey to study the
three-dimensional spatial distribution of matter and galaxies in the Abell
901/902 supercluster complex. Our method improves over the existing 3D lensing
mapping techniques by calibrating and removing redshift bias and accounting for
the effects of the radial elongation of 3D structures. We also include the
first detailed noise analysis of a 3D lensing map, showing that even with deep
HST quality data, only the most massive structures, for example M200>~10^15
Msun/h at z~0.8, can be resolved in 3D with any reasonable redshift accuracy
(\Delta z~0.15). We compare the lensing map to the stellar mass distribution
and find luminous counterparts for all mass peaks detected with a peak
significance >3\sigma. We see structures in and behind the z=0.165 foreground
supercluster, finding structure directly behind the A901b cluster at z~0.6 and
also behind the SW group at z~0.7. This 3D structure viewed in projection has
no significant impact on recent mass estimates of A901b or the SW group
components SWa and SWb.
| arxiv topic:astro-ph.CO |
arxiv_dataset-28541109.1032 | Tech Report A Variational HEM Algorithm for Clustering Hidden Markov
Models
cs.AI stat.ML
The hidden Markov model (HMM) is a generative model that treats sequential
data under the assumption that each observation is conditioned on the state of
a discrete hidden variable that evolves in time as a Markov chain. In this
paper, we derive a novel algorithm to cluster HMMs through their probability
distributions. We propose a hierarchical EM algorithm that i) clusters a given
collection of HMMs into groups of HMMs that are similar, in terms of the
distributions they represent, and ii) characterizes each group by a "cluster
center", i.e., a novel HMM that is representative for the group. We present
several empirical studies that illustrate the benefits of the proposed
algorithm.
| arxiv topic:cs.AI stat.ML |
arxiv_dataset-28551109.1132 | Double hadron lepto-production in the current and target fragmentation
regions
hep-ph
We study the inclusive production of two hadrons in deep inelastic processes,
l N ---> l h_1 h_2 X, with h_1 in the current fragmentation region (CFR) and
h_2 in the target fragmentation region (TFR). Assuming a factorized scheme, the
recently introduced polarized and transverse momentum dependent fracture
functions couple to the transverse momentum dependent fragmentation functions.
This allows the full exploration of the fracture functions for transversely
polarized quarks. Some particular cases are considered.
| arxiv topic:hep-ph |
arxiv_dataset-28561109.1232 | A critical look at the role of the bare parameters in the
renormalization of Phi-derivable approximations
hep-th hep-ph nucl-th
We revisit the renormalization of Phi-derivable approximations from a
slightly different point of view than the one which is usually followed in
previous works. We pay particular attention to the question of the existence of
a solution to the self-consistent equation that defines the two-point function
in the Cornwall-Jackiw-Tomboulis formalism and to the fact that some of the
ultraviolet divergences which appear if one formally expands the solution in
powers of the bare coupling do not always appear as divergences at the level of
the solution itself. We discuss these issues using a particular truncation of
the Phi functional, namely the simplest truncation which brings non-trivial
momentum and field dependence to the two-point function.
| arxiv topic:hep-th hep-ph nucl-th |
arxiv_dataset-28571109.1332 | Formation of singularity for compressible viscoelasticity
math.AP
The formation of singularity and breakdown of classical solutions to the
three-dimensional compressible viscoelasticity and inviscid elasticity are
considered. For the compressible inviscid elastic fluids, the finite-time
formation of singularity in classical solutions is proved for certain initial
data. For the compressible viscoelastic fluids, a criterion in term of the
temporal integral of the velocity gradient is obtained for the breakdown of
smooth solutions.
| arxiv topic:math.AP |
arxiv_dataset-28581109.1432 | The Nevanlinna-Pick matrix interpolation in the Carath\'eodory class
with infinite data both in the nondegenerate and degenerate cases
math.FA
In this paper we study the Nevanlinna-Pick matrix interpolation problem in
the Carath\'eodory class with infinite data (both in the nondegenerate and
degenerate cases). We develop the Sz\"okefalvi-Nagy and Kor\'anyi operator
approach to obtain an analytic description of all solutions of the problem.
Simple necessary and sufficient conditions for the determinacy of the problem
are given.
| arxiv topic:math.FA |
arxiv_dataset-28591109.1532 | Application of the confluent Heun functions for finding the quasinormal
modes of nonrotating black holes
gr-qc astro-ph.HE
Although finding numerically the quasinormal modes of a nonrotating black
hole is a well-studied question, the physics of the problem is often hidden
behind complicated numerical procedures aimed at avoiding the direct solution
of the spectral system in this case. In this article, we use the exact
analytical solutions of the Regge-Wheeler equation and the Teukolsky radial
equation, written in terms of confluent Heun functions. In both cases, we
obtain the quasinormal modes numerically from spectral condition written in
terms of the Heun functions. The frequencies are compared with ones already
published by Andersson and other authors. A new method of studying the branch
cuts in the solutions is presented -- the epsilon-method. In particular, we
prove that the mode $n=8$ is not algebraically special and find its value with
more than 6 firm figures of precision for the first time. The stability of that
mode is explored using the $\epsilon$ method, and the results show that this
new method provides a natural way of studying the behavior of the modes around
the branch cut points.
| arxiv topic:gr-qc astro-ph.HE |
arxiv_dataset-28601109.1632 | Many, many more intrinsically knotted graphs
math.GT
We list more than 200 new examples of minor minimal intrinsically knotted
graphs and describe many more that are intrinsically knotted and likely minor
minimal.
| arxiv topic:math.GT |
arxiv_dataset-28611109.1732 | Characteristic spatial scale of vesicle pair interactions in a plane
linear flow
cond-mat.soft nlin.CD physics.flu-dyn
We report the experimental studies on interaction of two vesicles trapped in
a microfluidic analog of four-roll mill, where a plane linear flow is realized.
We found that the dynamics of a single vesicle is significantly altered by the
presence of another vesicle at separation distances up to about 3.2 \div 3.7
times of effective radius of the vesicles. This is supported by direct
measurements of a single vesicle back-reaction on the velocity field. Thus, the
experiment provides the lower bound for the interaction scale of vesicles and
so the corresponding upper bound for the volume fraction \phi=0.08 \div 0.13 of
non-interacting vesicle suspensions.
| arxiv topic:cond-mat.soft nlin.CD physics.flu-dyn |
arxiv_dataset-28621109.1832 | Revisiting the implications of CPT and unitarity for baryogenesis and
leptogenesis
hep-ph
In the context of GUT baryogenesis models, a well-known theorem asserts that
CPT conservation and the unitarity of S-matrix require that the lowest order
contribution that leads to the generation of a non-zero net CP-violation via
the decay of a heavy particle must be to $\mathcal{O}({\alpha_\slashed{B}}^3)$,
where $\alpha_\slashed{B}$ is a baryon number (B) violating coupling. We
revisit this theorem (which holds for lepton number (L) violation, and hence
for leptogenesis as well) and examine its implications for models where the
particle content allows the heavy particle to also decay via modes which
conserve B (or L) in addition to modes which do not. We systematically expand
the S-matrix order by order in B\slash L-violating couplings, and show, in such
cases, that the net CP-violation is non-zero even to
$\mathcal{O}({\alpha_\slashed{B}}^2)$, without actually contradicting the
theorem. By replacing a B/L violating coupling (usually constrained to be
small) by a relatively unconstrained B/L conserving one, our result may allow
for sufficient CP violation in models where it may otherwise have been
difficult to generate the observed baryon asymmetry. As an explicit application
of this result, we construct a model in low-scale leptogenesis.
| arxiv topic:hep-ph |
arxiv_dataset-28631109.1932 | Enrichment and aggregation of topological motifs are independent
organizational principles of integrated interaction networks
q-bio.MN
Topological network motifs represent functional relationships within and
between regulatory and protein-protein interaction networks. Enriched motifs
often aggregate into self-contained units forming functional modules.
Theoretical models for network evolution by duplication-divergence mechanisms
and for network topology by hierarchical scale-free networks have suggested a
one-to-one relation between network motif enrichment and aggregation, but this
relation has never been tested quantitatively in real biological interaction
networks. Here we introduce a novel method for assessing the statistical
significance of network motif aggregation and for identifying clusters of
overlapping network motifs. Using an integrated network of transcriptional,
posttranslational and protein-protein interactions in yeast we show that
network motif aggregation reflects a local modularity property which is
independent of network motif enrichment. In particular our method identified
novel functional network themes for a set of motifs which are not enriched yet
aggregate significantly and challenges the conventional view that network motif
enrichment is the most basic organizational principle of complex networks.
| arxiv topic:q-bio.MN |
arxiv_dataset-28641109.2032 | Compact antenna for efficient and unidirectional launching and
decoupling of surface plasmons
physics.optics
Controlling the launching efficiencies and the directionality of surface
plasmon polaritons (SPPs) and their decoupling to freely propagating light is a
major goal for the development of plasmonic devices and systems. Here, we
report on the design and experimental observation of a highly efficient
unidirectional surface plasmon launcher composed of eleven subwavelength
grooves, each with a distinct depth and width. Our observations show that,
under normal illumination by a focused Gaussian beam, unidirectional SPP
launching with an efficiency of at least 52% is achieved experimentally with a
compact device of total length smaller than 8 \mu m. Reciprocally, we report
that the same device can efficiently convert SPPs into a highly directive light
beam emanating perpendicularly to the sample.
| arxiv topic:physics.optics |
arxiv_dataset-28651109.2132 | Hybrid BDI-POMDP Framework for Multiagent Teaming
cs.MA
Many current large-scale multiagent team implementations can be characterized
as following the belief-desire-intention (BDI) paradigm, with explicit
representation of team plans. Despite their promise, current BDI team
approaches lack tools for quantitative performance analysis under uncertainty.
Distributed partially observable Markov decision problems (POMDPs) are well
suited for such analysis, but the complexity of finding optimal policies in
such models is highly intractable. The key contribution of this article is a
hybrid BDI-POMDP approach, where BDI team plans are exploited to improve POMDP
tractability and POMDP analysis improves BDI team plan performance. Concretely,
we focus on role allocation, a fundamental problem in BDI teams: which agents
to allocate to the different roles in the team. The article provides three key
contributions. First, we describe a role allocation technique that takes into
account future uncertainties in the domain; prior work in multiagent role
allocation has failed to address such uncertainties. To that end, we introduce
RMTDP (Role-based Markov Team Decision Problem), a new distributed POMDP model
for analysis of role allocations. Our technique gains in tractability by
significantly curtailing RMTDP policy search; in particular, BDI team plans
provide incomplete RMTDP policies, and the RMTDP policy search fills the gaps
in such incomplete policies by searching for the best role allocation. Our
second key contribution is a novel decomposition technique to further improve
RMTDP policy search efficiency. Even though limited to searching role
allocations, there are still combinatorially many role allocations, and
evaluating each in RMTDP to identify the best is extremely difficult. Our
decomposition technique exploits the structure in the BDI team plans to
significantly prune the search space of role allocations. Our third key
contribution is a significantly faster policy evaluation algorithm suited for
our BDI-POMDP hybrid approach. Finally, we also present experimental results
from two domains: mission rehearsal simulation and RoboCupRescue disaster
rescue simulation.
| arxiv topic:cs.MA |
arxiv_dataset-28661109.2232 | A New Proposed Cost Model for List Accessing Problem using Buffering
cs.DS
There are many existing well known cost models for the list accessing
problem. The standard cost model developed by Sleator and Tarjan is most widely
used. In this paper, we have made a comprehensive study of the existing cost
models and proposed a new cost model for the list accessing problem. In our
proposed cost model, for calculating the processing cost of request sequence
using a singly linked list, we consider the access cost, matching cost and
replacement cost. The cost of processing a request sequence is the sum of
access cost, matching cost and replacement cost. We have proposed a novel
method for processing the request sequence which does not consider the
rearrangement of the list and uses the concept of buffering, matching, look
ahead and flag bit.
| arxiv topic:cs.DS |
arxiv_dataset-28671109.2332 | Modified geodetic brane cosmology
gr-qc
We explore the cosmological implications provided by the geodetic brane
gravity action corrected by an extrinsic curvature brane term, describing a
codimension-1 brane embedded in a 5D fixed Minkowski spacetime. In the geodetic
brane gravity action, we accommodate the correction term through a linear term
in the extrinsic curvature swept out by the brane. We study the resulting
geodetic-type equation of motion. Within a Friedmann-Robertson-Walker metric,
we obtain a generalized Friedmann equation describing the associated
cosmological evolution. We observe that, when the radiation-like energy
contribution from the extra dimension is vanishing, this effective model leads
to a self-(non-self)-accelerated expansion of the brane-like universe in
dependence on the nature of the concomitant \beta-parameter associated with the
correction, which resembles an analogous behaviour in the DGP brane cosmology.
Several possibilities in the description for the cosmic evolution of this model
are embodied and characterized by the involved density parameters related in
turn to the cosmological constant, the geometry characterizing the model, the
introduced \beta-parameter as well as the dark like-energy and the matter
content on the brane.
| arxiv topic:gr-qc |
arxiv_dataset-28681109.2432 | Micro helical polymeric structures produced by variable voltage direct
electrospinning
cond-mat.soft cond-mat.mtrl-sci physics.bio-ph physics.flu-dyn q-bio.TO
Direct near field electrospinning is used to produce very long helical
polystyrene microfibers in water. The pitch length of helices can be controlled
by changing the applied voltage, allowing to produce both micro springs and
microchannels. Using a novel high frequency variable voltage electrospinning
method we found the helix formation speed and compared the experimental
buckling frequency to theoretical expressions for viscous and elastic buckling.
Finally we showed that the newmethod can be used to produce new periodic micro
and nano structures.
| arxiv topic:cond-mat.soft cond-mat.mtrl-sci physics.bio-ph physics.flu-dyn q-bio.TO |
arxiv_dataset-28691109.2532 | Anomalous flux avalanche morphology in a a-MoGe superconducting film
with a square antidot lattice - experiment and simulation
cond-mat.supr-con
We have employed magneto-optical imaging to visualize the occurrence of flux
avalanches in a superconducting film of a-MoGe. The specimen was decorated with
square antidots arranged in a square lattice. We observed avalanches with the
anomalous habit of forming trees where the trunk is perpendicular to the main
axis of the square lattice, whereas the branches form angles of 45 degrees. The
overall features of the avalanches, and in particular the 45 degree direction
of the branches, were confirmed by numerical simulations.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-28701109.2632 | Enhanced control of excimer laser pulse timing using tunable additive
noise
physics.ins-det
Recently we have shown a system developed to precisely control the laser
pulse timing of excimer lasers [1]. The electronic circuit based on an embedded
microcontroller and utilized the natural jitter noise of the laser pulse
generation to improve the long term regulation of the delay of the laser
related to an external trigger pulse. Based on our results we have developed an
improved system that uses additional, programmable time delay units to tune the
noise source to further enhance performance and allows reduction of complexity
in the same time. A mixed-signal microcontroller generates a randomly dithered
delay of the pulse generation moment to enhance the resolution and also runs a
dedicated algorithm to optimize regulation. The compact, flexible hardware
supports further enhancements; the signal processing algorithm can be replaced
even by in-system reprogramming. Optimized processing and the relaxed hardware
requirements may also support low-power operation, wireless communication,
therefore the application possibilities may be extended to many other
disciplines.
| arxiv topic:physics.ins-det |
arxiv_dataset-28711109.2732 | Shape and orientation of the gas distribution in A1689
astro-ph.CO
Knowledge of intrinsic shape and orientation of galaxy clusters is crucial to
understand their formation and evolution. We propose a novel model which uses
Bayesian inference to determine the intrinsic form of the hot intracluster
medium of galaxy clusters. The method exploits X-ray spectroscopic and
photometric data plus measurements of the Sunyaev-Zel'dovich effect (SZe). The
gas distribution is modelled with an ellipsoidal parametric profile who can fit
observed X-ray surface-brightness and temperature. Comparison with the SZ
amplitude fixes the elongation along the line of sight. Finally, Bayesian
inference allows us to deproject the measured elongation and the projected
ellipticity and constrain the intrinsic shape and orientation of the cluster.
We apply the method to the rich cluster Abell 1689, which was targeted by the
Chandra and XMM satellites as well as by several SZe observatories.
Observations cover in detail a region <~ 1 Mpc. Our analysis favours a mildly
triaxial cluster with a minor to major axis ratio of 0.70+-0.15, preferentially
elongated along the line of sight, as expected for massive lensing clusters.
The triaxial structure together with the orientation bias can reconcile X-ray
with lensing analyses and supports the view of A1689 as a just slightly
over-concentrated massive cluster not so far from hydrostatic equilibrium.
| arxiv topic:astro-ph.CO |
arxiv_dataset-28721109.2832 | Jack superpolynomials with negative fractional parameter: clustering
properties and super-Virasoro ideals
math-ph hep-th math.CO math.MP
The Jack polynomials P_\lambda^{(\alpha)} at \alpha=-(k+1)/(r-1) indexed by
certain (k,r,N)-admissible partitions are known to span an ideal I^{(k,r)}_N of
the space of symmetric functions in N variables. The ideal I^{(k,r)}_N is
invariant under the action of certain differential operators which include half
the Virasoro algebra. Moreover, the Jack polynomials in I^{(k,r)}_N admit
clusters of size at most k: they vanish when k+1 of their variables are
identified, and they do not vanish when only k of them are identified. We
generalize most of these properties to superspace using orthogonal
eigenfunctions of the supersymmetric extension of the trigonometric
Calogero-Moser-Sutherland model known as Jack superpolynomials. In particular,
we show that the Jack superpolynomials P_{\Lambda}^{(\alpha)} at
\alpha=-(k+1)/(r-1) indexed by certain (k,r,N)-admissible superpartitions span
an ideal {\mathcal I}^{(k,r)}_N of the space of symmetric polynomials in N
commuting variables and N anticommuting variables. We prove that the ideal
{\mathcal I}^{(k,r)}_N is stable with respect to the action of the
negative-half of the super-Virasoro algebra. In addition, we show that the Jack
superpolynomials in {\mathcal I}^{(k,r)}_N vanish when k+1 of their commuting
variables are equal, and conjecture that they do not vanish when only k of them
are identified. This allows us to conclude that the standard Jack polynomials
with prescribed symmetry should satisfy similar clustering properties. Finally,
we conjecture that the elements of {\mathcal I}^{(k,2)}_N provide a basis for
the subspace of symmetric superpolynomials in N variables that vanish when k+1
commuting variables are set equal to each other.
| arxiv topic:math-ph hep-th math.CO math.MP |
arxiv_dataset-28731109.2932 | Incidence and Abel-Jacobi equivalence
math.AG
For an algebraic (n-1)-cycle Z on a complex projective (2n-1)-manifold X, P.
Griffiths conjectured that, if Z is algebraically equivalent to zero and if the
incidence divisor of Z on every family of (n-1)-cycles is principal, then the
Abel-Jacobi image of Z in the intermediate Jacobian J(X) of X is a point of
finite order. Using a recent generalization of the classical height pairing, we
give a proof of a stronger statement, namely that the Abel-Jacobi image of Z is
zero.
| arxiv topic:math.AG |
arxiv_dataset-28741109.3032 | Study of $\bar B\to \Lambda\bar p\,\rho(\phi)$ and $\bar B\to
\Lambda\bar \Lambda \bar K^{*}$
hep-ph hep-ex
We examine the three-body baryonic $\bar B\to {\bf B\bar B'}V$ decays with
$V$ vector mesons in the standard model. We can simultaneously explain the
recent experimental data on the decays of $B^-\to \Lambda\bar p \,\rho^0$ and
$\bar B\to \Lambda\bar \Lambda \bar K^{*}$ based on the QCD counting rules and
SU(3) flavor symmetry. We also predict that the decay branching ratios of $\bar
B^0\to \Lambda\bar p \,\rho^+$ and $B^-\to \Lambda\bar p \,\phi$ are 3.0 and
$1.5\times 10^{-6}$, respectively, which are promising to be observed by BELLE
and BABAR at the $B$ factories.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-28751109.3132 | Dirichlet to Neumann Maps for Infinite Quantum Graphs
math.AP
The Dirichlet problem and Dirichlet to Neumann map are analyzed for elliptic
equations on a large collection of infinite quantum graphs. For a dense set of
continuous functions on the graph boundary, the Dirichlet to Neumann map has
values in the Radon measures on the graph boundary.
| arxiv topic:math.AP |
arxiv_dataset-28761109.3232 | Transverse momentum dependent twist-three result for polarized Drell-Yan
processes
hep-ph
We study the polarized Drell-Yan processes from the collision of two spin-1/2
hadrons at order 1/Q based on the framework of transverse momentum dependent
factorization.We give the complete twist-three results of total sixteen
independent structure functions in terms of twist-two and twist-three
transverse momentum dependent distribution functions.
| arxiv topic:hep-ph |
arxiv_dataset-28771109.3332 | Bursting synchronization in networks with long-range coupling mediated
by a diffusing chemical substance
nlin.CD
Many networks of physical and biological interest are characterized by a
long-range coupling mediated by a chemical which diffuses through a medium in
which oscillators are embedded. We considered a one-dimensional model for this
effect for which the diffusion is fast enough so as to be implemented through a
coupling whose intensity decays exponentially with the lattice distance. In
particular, we analyzed the bursting synchronization of neurons described by
two timescales (spiking and bursting activity), and coupled through such a
long-range interaction network. One of the advantages of the model is that one
can pass from a local (Laplacian) type of coupling to a global (all-to-all) one
by varying a single parameter in the interaction term. We characterized
bursting synchronization using an order parameter which undergoes a transition
as the coupling parameters are changed through a critical value. We also
investigated the role of an external time-periodic signal on the bursting
synchronization properties of the network. We show potential applications in
the control of pathological rhythms in biological neural networks.
| arxiv topic:nlin.CD |
arxiv_dataset-28781109.3432 | Kepler-16: A Transiting Circumbinary Planet
astro-ph.EP
We report the detection of a planet whose orbit surrounds a pair of low-mass
stars. Data from the Kepler spacecraft reveal transits of the planet across
both stars, in addition to the mutual eclipses of the stars, giving precise
constraints on the absolute dimensions of all three bodies. The planet is
comparable to Saturn in mass and size, and is on a nearly circular 229-day
orbit around its two parent stars. The eclipsing stars are 20% and 69% as
massive as the sun, and have an eccentric 41-day orbit. The motions of all
three bodies are confined to within 0.5 degree of a single plane, suggesting
that the planet formed within a circumbinary disk.
| arxiv topic:astro-ph.EP |
arxiv_dataset-28791109.3532 | A Characterization of the Combined Effects of Overlap and Imbalance on
the SVM Classifier
cs.AI
In this paper we demonstrate that two common problems in Machine
Learning---imbalanced and overlapping data distributions---do not have
independent effects on the performance of SVM classifiers. This result is
notable since it shows that a model of either of these factors must account for
the presence of the other. Our study of the relationship between these problems
has lead to the discovery of a previously unreported form of "covert"
overfitting which is resilient to commonly used empirical regularization
techniques. We demonstrate the existance of this covert phenomenon through
several methods based around the parametric regularization of trained SVMs. Our
findings in this area suggest a possible approach to quantifying overlap in
real world data sets.
| arxiv topic:cs.AI |
arxiv_dataset-28801109.3632 | On chiral quantum superspaces
hep-th math.QA
We give a quantum deformation of the chiral Minkowski superspace in 4
dimensions embedded as the big cell into the chiral conformal superspace. Both
deformations are realized as quantum homogeneous superspaces: we deform the
ring of regular functions together with a coaction of the corresponding quantum
supergroup.
| arxiv topic:hep-th math.QA |
arxiv_dataset-28811109.3732 | On the Convergence of Finite Order Approximations of Stationary Time
Series
math.ST math.SP stat.TH
The approximation of a stationary time-series by finite order autoregressive
(AR) and moving averages (MA) is a problem that occurs in many applications. In
this paper we study asymptotic behavior of the spectral density of finite order
approximations of wide sense stationary time series. It is shown that when the
on the spectral density is non-vanishing in $[-\pi,\pi]$ and the covariance is
summable, the spectral density of the approximating autoregressive sequence
converges at the origin. Under additional mild conditions on the coefficients
of the Wold decomposition it is also shown that the spectral densities of both
moving average and autoregressive approximations converge in $L_2$ as the order
of approximation increases.
| arxiv topic:math.ST math.SP stat.TH |
arxiv_dataset-28821109.3832 | Analysis and Approximation of the Canonical Polyadic Tensor
Decomposition
math.NA
We study the least-squares (LS) functional of the canonical polyadic (CP)
tensor decomposition. Our approach is based on the elimination of one factor
matrix which results in a reduced functional. The reduced functional is
reformulated into a projection framework and into a Rayleigh quotient. An
analysis of this functional leads to several conclusions: new sufficient
conditions for the existence of minimizers of the LS functional, the existence
of a critical point in the rank-one case, a heuristic explanation of "swamping"
and computable bounds on the minimal value of the LS functional. The latter
result leads to a simple algorithm -- the Centroid Projection algorithm -- to
compute suboptimal solutions of tensor decompositions. These suboptimal
solutions are applied to iterative CP algorithms as initial guesses, yielding a
method called centroid projection for canonical polyadic (CPCP) decomposition
which provides a significant speedup in our numerical experiments compared to
the standard methods.
| arxiv topic:math.NA |
arxiv_dataset-28831109.3932 | On transversally harmonic maps of foliated Riemannian manifolds
math.DG
We study the transversally harmonic maps between foliated Riemannian
manifolds. In particular, we prove that under some curvature conditions, any
transversally harmonic map is transversally totally geodesic.
| arxiv topic:math.DG |
arxiv_dataset-28841109.4032 | Error estimates for finite difference approximations of American put
option price
q-fin.CP cs.SY math.NA math.OC math.PR q-fin.PR
Finite difference approximations to multi-asset American put option price are
considered. The assets are modelled as a multi-dimensional diffusion process
with variable drift and volatility. Approximation error of order one quarter
with respect to the time discretisation parameter and one half with respect to
the space discretisation parameter is proved by reformulating the corresponding
optimal stopping problem as a solution of a degenerate Hamilton-Jacobi-Bellman
equation. Furthermore, the error arising from restricting the discrete problem
to a finite grid by reducing the original problem to a bounded domain is
estimated.
| arxiv topic:q-fin.CP cs.SY math.NA math.OC math.PR q-fin.PR |
arxiv_dataset-28851109.4132 | On two-qubit states ordering with quantum discords
quant-ph cond-mat.stat-mech math-ph math.MP
The counterintuitive effect of non-unique ordering of two-qubit states with
quantum entanglement measures was discovered over ten years ago. More
precisely, it was shown by Monte Carlo simulations that there exist states for
which the entanglement of formation and the negativity do not impose the same
ordering of states, i.e. $E_{F}(\rho_{AB}) \leq (\geq)
E_{F}(\rho_{AB}^{\prime})$ is not equivalent to $N(\rho_{AB}) \leq (\geq)
N(\rho_{AB}^{\prime})$. Recently, it was discovered that quantum discord and
the geometric quantum discord do not necessarily imply the same ordering of
two-qubit $X$-states, which means that the lack of the unique ordering of
states with quantum entanglement measures goes beyond entanglement. Inspired by
this observation, we study the problem of the states ordering with quantum
discords, considering two-qubit Bell-diagonal states for analytical simplicity.
In particular, we identify some classes of states for which the states ordering
with quantum discords is preserved as long as the states belong to the same
class and give a few illustrative examples.
| arxiv topic:quant-ph cond-mat.stat-mech math-ph math.MP |
arxiv_dataset-28861109.4232 | Protein multi-scale organization through graph partitioning and
robustness analysis: Application to the myosin-myosin light chain interaction
q-bio.BM
Despite the recognized importance of the multi-scale spatio-temporal
organization of proteins, most computational tools can only access a limited
spectrum of time and spatial scales, thereby ignoring the effects on protein
behavior of the intricate coupling between the different scales. Starting from
a physico-chemical atomistic network of interactions that encodes the structure
of the protein, we introduce a methodology based on multi-scale graph
partitioning that can uncover partitions and levels of organization of proteins
that span the whole range of scales, revealing biological features occurring at
different levels of organization and tracking their effect across scales.
Additionally, we introduce a measure of robustness to quantify the relevance of
the partitions through the generation of biochemically-motivated surrogate
random graph models. We apply the method to four distinct conformations of
myosin tail interacting protein, a protein from the molecular motor of the
malaria parasite, and study properties that have been experimentally addressed
such as the closing mechanism, the presence of conserved clusters, and the
identification through computational mutational analysis of key residues for
binding.
| arxiv topic:q-bio.BM |
arxiv_dataset-28871109.4332 | Simulating radiative shocks in nozzle shock tubes
astro-ph.SR physics.plasm-ph
We use the recently developed Center for Radiative Shock Hydrodynamics
(CRASH) code to numerically simulate laser-driven radiative shock experiments.
These shocks are launched by an ablated beryllium disk and are driven down
xenon-filled plastic tubes. The simulations are initialized by the
two-dimensional version of the Lagrangian Hyades code which is used to evaluate
the laser energy deposition during the first 1.1ns. The later times are
calculated with the CRASH code. This code solves for the multi-material
hydrodynamics with separate electron and ion temperatures on an Eulerian
block-adaptive-mesh and includes a multi-group flux-limited radiation diffusion
and electron thermal heat conduction. The goal of the present paper is to
demonstrate the capability to simulate radiative shocks of essentially
three-dimensional experimental configurations, such as circular and elliptical
nozzles. We show that the compound shock structure of the primary and wall
shock is captured and verify that the shock properties are consistent with
order-of-magnitude estimates. The produced synthetic radiographs can be used
for comparison with future nozzle experiments at high-energy-density laser
facilities.
| arxiv topic:astro-ph.SR physics.plasm-ph |
arxiv_dataset-28881109.4432 | Wgamma production and limits on anomalous WWgamma couplings in ppbar
collisions
hep-ex
We measure the cross section and the difference in rapidities between photons
and charged leptons for inclusive W -> lnu+gamma production in egamma and
mugamma final states. Using data corresponding to an integrated luminosity of
4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the
cross section multiplied by the branching fraction for the process ppbar ->
Wgamma+X -> lnugamma+X, measured to be 15.8 +/- 0.8 (stat.) +/- 1.2 (syst.) pb,
and the distribution of the charge-signed photon-lepton rapidity difference are
found to be in agreement with the standard model. These results provide the
most stringent limits on anomalous WWgamma couplings for data from hadron
colliders: -0.4 < Delta kappa_gamma < 0.4 and -0.08 < lambda_gamma < 0.07 at
the 95% C.L.
| arxiv topic:hep-ex |
arxiv_dataset-28891109.4532 | K\"ahler-Weyl manifolds of dimension 4
math.DG
We determine the space of algebraic pseudo-Hermitian K\"ahler-Weyl curvature
tensors and the space of para-Hermitian K\"ahler-Weyl curvature tensors in
dimension 4 and show that every algebraic possibility is geometrically
realizable. We establish the Gray identity for pseudo-Hermitian Weyl manifolds
and for para-Hermitian Weyl manifolds in arbitrary dimension.
| arxiv topic:math.DG |
arxiv_dataset-28901109.4632 | A new cosmological distance measure using AGN
astro-ph.CO
Accurate distances to celestial objects are key to establishing the age and
energy density of the Universe and the nature of dark energy. A distance
measure using active galactic nuclei (AGN) has been sought for more than forty
years, as they are extremely luminous and can be observed at very large
distances. We report here the discovery of an accurate luminosity distance
measure using AGN. We use the tight relationship between the luminosity of an
AGN and the radius of its broad line region established via reverberation
mapping to determine the luminosity distances to a sample of 38 AGN. All
reliable distance measures up to now have been limited to moderate redshift --
AGN will, for the first time, allow distances to be estimated to z~4, where
variations of dark energy and alternate gravity theories can be probed.
| arxiv topic:astro-ph.CO |
arxiv_dataset-28911109.4732 | Neutron to proton mass difference, parton distribution functions and
baryon resonances from dynamics on the Lie group u(3)
hep-th hep-ex
We present a hamiltonian structure on the Lie group u(3) to describe the
baryon spectrum. The ground state is identified with the proton. From this
single fit we calculate approximately the relative neutron to proton mass shift
to within half a percentage of the experimental value. From the same fit we
calculate the nucleon and delta resonance spectrum with correct grouping and no
missing resonances. For specific spin eigenfunctions we calculate the delta to
nucleon mass ratio to within one percent. Finally we derive parton distribution
functions that compare well with those for the proton valence quarks. The
distributions are generated by projecting the proton state to space via the
exterior derivative on u(3). We predict scarce neutral flavour singlets which
should be visible in neutron diffraction dissociation experiments or in
invariant mass spectra of protons and negative pions in B-decays and in
photoproduction on neutrons. The presence of such singlet states distinguishes
experimentally the present model from the standard model as does the prediction
of the neutron to proton mass splitting. Conceptually the Hamiltonian may
describe an effective phenomenology or more radically describe interior
dynamics implying quarks and gluons as projections from u(3) which we then call
allospace.
| arxiv topic:hep-th hep-ex |
arxiv_dataset-28921109.4832 | Bell Inequality Tests with Macroscopic Entangled States of Light
quant-ph
Quantum correlations may violate the Bell inequalities. Most of the
experimental schemes confirming this prediction have been realized in
all-optical Bell tests suffering from the detection loophole. Experiment which
closes this loophole and the locality loophole simultaneously is highly
desirable and remains challenging. A novel approach to a loophole-free Bell
tests is based on amplification of the entangled photons, i.e.\@ on macroscopic
entanglement, which optical signal should be easy to detect. However, the
macroscopic states are partially indistinguishable by the classical detectors.
An interesting idea to overcome these limitations is to replace the
postselection by an appropriate preselection immediately after the
amplification. This is in the spirit of state preprocessing revealing hidden
nonlocality. Here, we examine one of possible preselections, but the presented
tools can be used for analysis of other schemes. Filtering methods making the
macroscopic entanglement useful for Bell test and quantum protocols are the
subject of an intensive study in the field nowadays.
| arxiv topic:quant-ph |
arxiv_dataset-28931109.4932 | Quantum noise and mode nonorthogonality in nonhermitian PT-symmetric
optical resonators
physics.optics
PT-symmetric optical resonators combine absorbing regions with active,
amplifying regions. The latter are the source of radiation generated via
spontaneous and stimulated emission, which embodies quantum noise and can
result in lasing. We calculate the frequency-resolved output radiation
intensity of such systems and relate it to a suitable measure of excess noise
and mode nonorthogonality. The lineshape differs depending on whether the
emission lines are isolated (as for weakly amplifying, almost hermitian
systems) or overlapping (as for the almost degenerate resonances in the
vicinity of exceptional points associated to spontaneous PT-symmetry breaking).
The calculations are carried out in the scattering input-output formalism, and
are illustrated for a quasi one-dimensional resonator set-up. In our
derivations we also allow for the more general case of a resonator in which the
amplifying and absorbing regions are not related by symmetry.
| arxiv topic:physics.optics |
arxiv_dataset-28941109.5032 | Transition temperature and the equation of state from lattice QCD,
Wuppertal-Budapest results
hep-lat
The QCD transition is studied on lattices up to $N_t=16$. The chiral
condensate is presented as a function of the temperature, and the corresponding
transition temperature is extracted. The equation of state is determined on
lattices with $N_t=6,8,10$ and at some temperature values with $N_t=12$. The
pressure and the trace anomaly are presented as functions of the temperature in
the range 100 ...1000 MeV . Using the same configurations we determine the
continuum extrapolated phase diagram of QCD on the $\mu-T$ plane for small to
moderate chemical potentials. Two transition lines are defined with two
quantities, the chiral condensate and the strange quark number susceptibility.
| arxiv topic:hep-lat |
arxiv_dataset-28951109.5132 | Bacterial persistence: a winning strategy?
math.PR q-bio.PE
It has long been known that antibiotic treatment will not completely kill off
a bacteria population. For many species a small fraction of bacteria is not
sensitive to antibiotics. These bacteria are said to persist. Recently it has
been shown that persistence is not a permanent state and that in fact a
bacterium can switch back and forth between persistent and non persistent
states. We introduce two stochastic models for bacteria persistence. In both
models there are mass killings of non persistent bacteria at certain times. The
first model has deterministic killing times and the second one has random
killing times. Both models suggest that persistence may be a successful
strategy for a wide range of parameter values.
| arxiv topic:math.PR q-bio.PE |
arxiv_dataset-28961109.5232 | Connecting the Reentrant Insulating Phase and the Zero Field
Metal-Insulator Transition in a 2D Hole System
cond-mat.str-el cond-mat.mes-hall
We present the transport and capacitance measurements of 10nm wide GaAs
quantum wells with hole densities around the critical point of the 2D
metal-insulator transition (critical density $p_c$ down to
0.8$\times10^{10}$/cm$^2$, $r_s\sim$36). For metallic hole density $p_c < p
<p_c +0.15\times10^{10}$/cm$^2$, a reentrant insulating phase (RIP) is observed
between the $\nu$=1 quantum Hall state and the zero field metallic state and is
attributed to the formation of pinned Wigner crystal. Through studying the
evolution of the RIP versus 2D hole density by transport and capacitance
experiments, we show that the RIP is incompressible and continuously connected
to the zero field insulator, suggesting a similar origin for these two phases.
| arxiv topic:cond-mat.str-el cond-mat.mes-hall |
arxiv_dataset-28971109.5332 | The Detectability of Moons of Extra-Solar Planets
astro-ph.EP
The detectability of moons of extra-solar planets is investigated, focussing
on the time-of-arrival perturbation technique, a method for detecting moons of
pulsar planets, and the photometric transit timing technique, a method for
detecting moons of transiting planets. Realistic thresholds are derived and
analysed in the in the context of the types of moons that are likely to form
and be orbitally stable for the lifetime of the system.
For the case of the time-of-arrival perturbation technique, the analysis is
conducted in two stages. First, a preliminary investigation is conducted
assuming that planet and moon's orbit are circular and coplanar. This analysis
is then applied to the case of the pulsar planet PSR B1620-26 b, and used to
conclude that a stable moon orbiting this pulsar planet could be detected, if
its mass was >5% of its planet's mass (2.5 Jupiter masses), and if the
planet-moon distance was ~ 2% of the planet-pulsar separation (23 AU).
Time-of-arrival expressions are then derived for mutually inclined as well as
non-circular orbits.
For the case of the photometric transit timing technique, a different
approach is adopted. First, analytic expressions for the timing perturbation
due to the moon are derived for the case where the orbit of the moon is
circular and coplanar with that of the planet and where the planet's orbit is
circular and aligned to the line-of-sight, circular and inclined with respect
to the line-of-sight or eccentric and aligned to the line-of-sight. Second, the
timing noise is investigated analytically, for the case of white photometric
noise, and numerically, using SOHO lightcurves, for the case of realistic and
filtered realistic photometric noise. [...] Abstract truncated due to the
limitations of astroph. See full abstract in the thesis.
| arxiv topic:astro-ph.EP |
arxiv_dataset-28981109.5432 | A classification of primitive permutation groups with finite stabilizers
math.GR
We classify all infinite primitive permutation groups possessing a finite
point stabilizer, thus extending the seminal Aschbacher-O'Nan-Scott Theorem to
all primitive permutation groups with finite point stabilizers.
| arxiv topic:math.GR |
arxiv_dataset-28991109.5532 | Electronic Transport in Metallic Systems and Generalized Kinetic
Equations
cond-mat.stat-mech cond-mat.str-el
This paper reviews some selected approaches to the description of transport
properties, mainly electroconductivity, in crystalline and disordered metallic
systems. A detailed qualitative theoretical formulation of the electron
transport processes in metallic systems within a model approach is given.
Generalized kinetic equations which were derived by the method of the
nonequilibrium statistical operator are used. Tight-binding picture and
modified tight-binding approximation (MTBA) were used for describing the
electron subsystem and the electron-lattice interaction correspondingly. The
low- and high-temperature behavior of the resistivity was discussed in detail.
The main objects of discussion are nonmagnetic (or paramagnetic) transition
metals and their disordered alloys. The choice of topics and the emphasis on
concepts and model approach makes it a good method for a better understanding
of the electrical conductivity of the transition metals and their disordered
binary substitutional alloys, but the formalism developed can be applied (with
suitable modification), in principle, to other systems. The approach we used
and the results obtained complements the existent theories of the electrical
conductivity in metallic systems. The present study extends the standard
theoretical format and calculation procedures in the theories of electron
transport in solids.
| arxiv topic:cond-mat.stat-mech cond-mat.str-el |
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