title: Flow of Navier-Stokes Fluids in Cylindrical Elastic Tubes

abstract:
  Analytical expressions correlating the volumetric flow rate to the inlet and
outlet pressures are derived for the time-independent flow of Newtonian fluids
in cylindrically-shaped elastic tubes using a one-dimensional Navier-Stokes
flow model with two pressure-area constitutive relations. These expressions for
elastic tubes are the equivalent of Poiseuille and Poiseuille-type expressions
for rigid tubes which were previously derived for the flow of Newtonian and
non-Newtonian fluids under various flow conditions. Formulae and procedures for
identifying the pressure field and tube geometric profile are also presented.
The results are validated by a finite element method implementation. Sensible
trends in the analytical and numerical results are observed and documented.

categories: physics.flu-dyn math-ph math.MP physics.bio-ph


title: Stieltjes Electrostatic Model Interpretation for Bound State Problems

abstract:
  In this paper, Stieltjes electrostatic model and quantum Hamilton Jacobi
formalism is analogous to each other is shown. This analogy allows, the bound
state problem to mimics as $n$ unit moving imaginary charges $i\hbar$, which
are placed in between the two fixed imaginary charges arising due to the
classical turning points of the potential. The interaction potential between
$n$ unit moving imaginary charges $i\hbar$ is given by logarithm of the wave
function. For an exactly solvable potential, this system attains stable
equilibrium position at the zeros of the orthogonal polynomials depending upon
the interval of the classical turning points.


title: Pointwise multipliers on martingale Campanato spaces

abstract:
  We introduce generalized Campanato spaces $\mathcal{L}_{p,\phi}$ on a
probability space $(\Omega,\mathcal{F},P)$, where $p\in[1,\infty)$ and
$\phi:(0,1]\to(0,\infty)$. If $p=1$ and $\phi\equiv1$, then
$\mathcal{L}_{p,\phi}=\mathrm{BMO}$. We give a characterization of the set of
all pointwise multipliers on $\mathcal{L}_{p,\phi}$.


title: Probe of extra dimensions in gamma q->gamma q at the LHC

abstract:
  We have examined TeV scale effects of extra spatial dimensions through the
processes gamma q-> gamma q where q=u,d,c,s,b, anti-u, anti-d, anti-c, anti-s,
anti-b. These processes have been treated in a photon-proton collision via the
main reaction pp-> p gamma p-> p gamma qX at the LHC. We have employed
equivalent photon approximation for incoming photon beams and performed
statistical analysis for various forward detector acceptances.


title: Microlensing in globular clusters: the first confirmed lens

abstract:
  Microlensing observations toward globular clusters could be very useful to
probe their low mass star and brown dwarf content. Using the large set of
microlensing events detected so far toward the Galactic centre we investigated
whether for some of the observed events the lenses are located in the Galactic
globular clusters. Indeed, we found that in four cases some events might be due
to lenses located in the globular clusters themselves. Moreover, we discuss a
microlensing event found in M22. Using the adaptive optics system NACO at ESO
VLT it was possible to identify the lens, which turned out to be a low mass
star of about 0.18 solar masses in the globular cluster M22 itself.


title:
On the Choquet-Bruhat-York-Friedrich formulation of the Einstein-Euler
  equations

abstract:
  Short-time existence for the Einstein-Euler and the vacuum Einstein equations
is proven using a Friedrich inspired formulation due to Choquet-Bruhat and
York, where the system is cast into a symmetric hyperbolic form and the Riemann
tensor is treated as one of the fundamental unknowns of the problem. The
reduced system of Choquet-Bruhat and York, along with the preservation of the
gauge, is shown to imply the full Einstein equations.


title: Solar-cycle precursors and predictions

abstract:
  The sunspot number data during the past 400 years indicates that both the
profile and the amplitude of the solar cycle have large variations. Some
precursors of the solar cycle were identified aiming to predict the solar
cycle. The polar field and the geomagnetic index are two precursors which are
received the most attention. The geomagnetic variations during the solar minima
are potentially caused by the solar polar field by the connection of the solar
open flux. The robust prediction skill of the polar field indicates that the
memory of the dynamo process is less than 11 yrs within the framework of the
Babcock-Leighton flux transport dynamo. One possible reason to get the short
magnetic memory is the high magnetic diffusivity in the convective zone. Our
recent studies show that the radial downward pumping is another possible
reason. Based upon the mechanism, we well simulate the cycle irregularities
during RGO time period. This opens the possibility to set up a standard dynamo
based model to predict the solar cycle. In the end, the no correlation between
the polar field and the preceding cycle strength due to the nonlinearities and
random mechanisms involved in the sunspot emergences are stressed.


title:
Perturbative calculation of the clover term for Wilson fermions in any
  representation of the gauge group SU(N)

abstract:
  We calculate the Sheikholeslami-Wohlert coefficient of the O(a) improvement
term for Wilson fermions in any representation of the gauge group SU(N)
perturbatively at the one-loop level. The result applies to QCD with adjoint
quarks and to N=1 supersymmetric Yang-Mills theory on the lattice.


title:
Nuclear suppression of light hadrons and single electrons at RHIC and
  LHC

abstract:
  We examine whether it is possible to simultaneously describe the experimental
data from RHIC and LHC on nuclear suppression of light hadrons and non-photonic
single electrons in the pQCD picture of parton energy loss. We perform
calculations accounting for both radiative and collisional energy loss. We show
that once the coupling constant is fixed from comparison with data on the
nuclear modification factor for light hadrons it gives a satisfactory agreement
with data on the electron R_{AA} and azimuthal anisotropy v_2. Our results show
that the collisional mechanism is only of marginal significance in nuclear
suppression of single electrons except for the bottom contribution at momenta <
6-8 GeV.


title:
Genericity versus expressivity - an exercise in semantic interoperable
  research information systems for Web Science

abstract:
  The web does not only enable new forms of science, it also creates new
possibilities to study science and new digital scholarship. This paper brings
together multiple perspectives: from individual researchers seeking the best
options to display their activities and market their skills on the academic job
market; to academic institutions, national funding agencies, and countries
needing to monitor the science system and account for public money spending. We
also address the research interests aimed at better understanding the
self-organising and complex nature of the science system through researcher
tracing, the identification of the emergence of new fields, and knowledge
discovery using large-data mining and non-linear dynamics. In particular this
paper draws attention to the need for standardisation and data interoperability
in the area of research information as an indispensable pre-condition for any
science modelling. We discuss which levels of complexity are needed to provide
a globally, interoperable, and expressive data infrastructure for research
information. With possible dynamic science model applications in mind, we
introduce the need for a "middle-range" level of complexity for data
representation and propose a conceptual model for research data based on a core
international ontology with national and local extensions.


title:
Finite-size effect on evolution of Griffiths phase in manganite
  nanoparticles

abstract:
  The finite-size effect on the evolution of Griffiths phase (GP) is studied
using nanoparticles of half-doped manganite Pr$_{0.5}$Sr$_{0.5}$MnO$_{3}$ with
different average particle sizes but having similar structural parameters. All
the samples exhibit pronounced GP behavior. With reducing particle size, the
Griffiths temperature remains almost unchanged but the characteristic critical
temperature $T_c^R$ decreases and the GP properties are strengthened. It is
noteworthy that the shift of $T_c^R$ follows finite-size scaling with the
particle size revealing an exotic interplay between the GP properties and the
sample dimension. This reinforces an earlier proposal of length-scale related
evolution of GP.


title: Proactive Data Download and User Demand Shaping for Data Networks

abstract:
  In this work, we propose and study optimal proactive resource allocation and
demand shaping for data networks. Motivated by the recent findings on the
predictability of human behavior patterns in data networks, and the emergence
of highly capable handheld devices, our design aims to smooth out the network
traffic over time and minimize the data delivery costs.
  Our framework utilizes proactive data services as well as smart content
recommendation schemes for shaping the demand. Proactive data services take
place during the off-peak hours based on a statistical prediction of a demand
profile for each user, whereas smart content recommendation assigns modified
valuations to data items so as to render the users' demand less uncertain.
Hence, our recommendation scheme aims to boost the performance of proactive
services within the allowed flexibility of user requirements. We conduct
theoretical performance analysis that quantifies the leveraged cost reduction
through the proposed framework. We show that the cost reduction scales at the
same rate as the cost function scales with the number of users. Further, we
prove that \emph{demand shaping} through smart recommendation strictly reduces
the incurred cost even below that of proactive downloads without
recommendation.


title: Long Circuits and Large Euler Subgraphs

abstract:
  An undirected graph is Eulerian if it is connected and all its vertices are
of even degree. Similarly, a directed graph is Eulerian, if for each vertex its
in-degree is equal to its out-degree. It is well known that Eulerian graphs can
be recognized in polynomial time while the problems of finding a maximum
Eulerian subgraph or a maximum induced Eulerian subgraph are NP-hard. In this
paper, we study the parameterized complexity of the following Euler subgraph
problems:
  - Large Euler Subgraph: For a given graph G and integer parameter k, does G
contain an induced Eulerian subgraph with at least k vertices?
  - Long Circuit: For a given graph G and integer parameter k, does G contain
an Eulerian subgraph with at least k edges?
  Our main algorithmic result is that Large Euler Subgraph is fixed parameter
tractable (FPT) on undirected graphs. We find this a bit surprising because the
problem of finding an induced Eulerian subgraph with exactly k vertices is
known to be W[1]-hard. The complexity of the problem changes drastically on
directed graphs. On directed graphs we obtained the following complexity
dichotomy: Large Euler Subgraph is NP-hard for every fixed k>3 and is solvable
in polynomial time for k<=3. For Long Circuit, we prove that the problem is FPT
on directed and undirected graphs.


title:
Maximum Score Estimation of Preference Parameters for a Binary Choice
  Model under Uncertainty

abstract:
  This paper develops maximum score estimation of preference parameters in the
binary choice model under uncertainty in which the decision rule is affected by
conditional expectations. The preference parameters are estimated in two
stages: we estimate conditional expectations nonparametrically in the first
stage and then the preference parameters in the second stage based on Manski
(1975, 1985)'s maximum score estimator using the choice data and first stage
estimates. The paper establishes consistency and derives rate of convergence of
the two-stage maximum score estimator. Moreover, the paper also provides
sufficient conditions under which the two-stage estimator is asymptotically
equivalent in distribution to the corresponding single-stage estimator that
assumes the first stage input is known. These results are of independent
interest for maximum score estimation with nonparametrically generated
regressors. The paper also presents some Monte Carlo simulation results for
finite-sample behavior of the two-stage estimator.


title:
Improved QCD sum rule study of $Z_{c}(3900)$ as a $\bar{D}D^{*}$
  molecular state

abstract:
  In the framework of QCD sum rules, we present an improved study of our
previous work [Phys. Rev. D {\bf80}, 056004 (2009)] particularly on the
$\bar{D}D^{*}$ molecular state to investigate that the possibility of the newly
observed $Z_{c}(3900)$ as a $S$-wave $\bar{D}D^{*}$ molecular state. To ensure
the quality of QCD sum rule analysis, contributions of up to dimension nine are
calculated to test the convergence of operator product expansion (OPE). We find
that the two-quark condensate $<\bar{q}q>$ is very large and makes the standard
OPE convergence (i.e. the perturbative at least larger than each condensate
contribution) happen at very large values of Borel parameters. By releasing the
rigid OPE convergence criterion, one could find that the OPE convergence is
still under control. We arrive at the numerical result $3.86\pm0.27 {GeV}$ for
$\bar{D}D^{*}$, which agrees with the mass of $Z_{c}(3900)$ and could support
the explanation of $Z_{c}(3900)$ in terms of a $S$-wave $\bar{D}D^{*}$
molecular state.


title: On Sidon sets which are asymptotic bases of order 4

abstract:
  In this paper we prove the existence of Sidon sets which are asymptotic bases
of order 4 by using probabilistic methods.


title:
Dynamic Magnetoelectric Effect in Ferromagnet-Superconductor Tunnel
  Junctions

abstract:
  We study the magnetization dynamics in a ferromagnet-insulator-superconductor
tunnel junction and the associated buildup of the electrical polarization. We
show that for an open circuit, the induced voltage varies strongly and
nonmonotonically with the precessional frequency, and can be enhanced
significantly by the superconducting correlations. For frequencies much smaller
or much larger than the superconducting gap, the voltage drops to zero, while
when these two energy scales are comparable, the voltage is peaked at a value
determined by the driving frequency. We comment on the potential utilization of
the effect for the low-temperature spatially-resolved spectroscopy of magnetic
dynamics.


title:
Direct and inverse pumping in flows with homogeneous and non-homogeneous
  swirl

abstract:
  The conditions in which meridional recirculations appear in swirling flows
above a fixed wall are analysed. In the classical Bodew\"adt problem, where the
swirl tends towards an aysmptotic value away from the wall, the well-known
"tea-cup effect" drives a flow away from the plate at the centre of the vortex.
Simple dimensional arguments applied to a single vortex show that if the
intensity of the swirl decreases away from the wall, the sense of the
recirculation can be inverted, and that the associated flow rate scales with
the swirl gradient. Only if the flow is quasi-2D, does the classical tea-cup
effect take place. This basic theory is confirmed by numerical simulations of a
square array of steady, electrically driven vortices. Experiments in the
turbulent regimes of the same configuration reveal that these mechanisms are
active in the average flow and in its fluctuating part. The mechanisms singled
out in this letter provide an explanation for previously observed phenomena in
electrolyte flows. They also put forward a possible mechanism for the
generation of helicity in flows close to two-dimensionality, which plays a key
role in the transition between 2D and 3D turbulence.


title: The R-matrix of quantum doubles of Nichols algebras of diagonal type

abstract:
  Let $H$ be the quantum double of a Nichols algebra of diagonal type. We
compute the $R$-matrix of 3-uples of modules for general finite-dimensional
highest weight modules over $H$.
  We calculate also a multiplicative formula for the universal $R$-matrix when
$H$ is finite dimensional.


title:
Mapping EINS -- An exercise in mapping the Network of Excellence in
  Internet Science

abstract:
  This paper demonstrates the application of bibliometric mapping techniques in
the area of funded research networks. We discuss how science maps can be used
to facilitate communication inside newly formed communities, but also to
account for their activities to funding agencies. We present the mapping of
EINS as case -- an FP7 funded Network of Excellence. Finally, we discuss how
these techniques can be used to serve as knowledge maps for interdisciplinary
working experts.


title:
A chip-scale, telecommunications-band frequency conversion interface for
  quantum emitters

abstract:
  We describe a chip-scale, telecommunications-band frequency conversion
interface designed for low-noise operation at wavelengths desirable for common
single photon emitters. Four-wave mixing Bragg scattering in silicon nitride
waveguides is used to demonstrate frequency upconversion and downconversion
between the 980 nm and 1550 nm wavelength regions, with signal-to-background
levels >10 and conversion efficiency of approximately -60 dB at low continuous
wave input pump powers (<50 mW). Finite element simulations and the split-step
Fourier method indicate that increased input powers of approximately 10 W
(produced by amplified nanosecond pulses, for example) will result in a
conversion efficiency >25 % in existing geometries. Finally, we present
waveguide designs that can be used to connect shorter wavelength (637 nm to 852
nm) quantum emitters with 1550 nm.


title: Policy Aware Geospatial Data

abstract:
  Digital Rights Management (DRM) prevents end-users from using content in a
manner inconsistent with its creator's wishes. The license describing these
use-conditions typically accompanies the content as its metadata. A resulting
problem is that the license and the content can get separated and lose track of
each other. The best metadata have two distinct qualities--they are created
automatically without user intervention, and they are embedded within the data
that they describe. If licenses are also created and transported this way, data
will always have licenses, and the licenses will be readily examinable. When
two or more datasets are combined, a new dataset, and with it a new license,
are created. This new license is a function of the licenses of the component
datasets and any additional conditions that the person combining the datasets
might want to impose. Following the notion of a data-purpose algebra, we model
this phenomenon by interpreting the transfer and conjunction of data as
inducing an algebraic operation on the corresponding licenses. When a dataset
passes from one source to the next its license is transformed in a
deterministic way, and similarly when datasets are combined the associated
licenses are combined in a non-trivial algebraic manner. Modern,
computer-savvy, licensing regimes such as Creative Commons allow writing the
license in a special kind of language called Creative Commons Rights Expression
Language (ccREL). ccREL allows creating and embedding the license using RDFa
utilizing XHTML. This is preferred over DRM which includes the rights in a
binary file completely opaque to nearly all users. The colocation of metadata
with human-visible XHTML makes the license more transparent. In this paper we
describe a methodology for creating and embedding licenses in geographic data
utilizing ccREL, and programmatically examining embedded licenses in component
data...


title:
Rapid quantitative pharmacodynamic imaging by a novel method: theory,
  simulation testing and proof of principle

abstract:
  Pharmacological challenge imaging has mapped, but rarely quantified, the
sensitivity of a biological system to a given drug. We describe a novel method
called rapid quantitative pharmacodynamic imaging. This method combines
pharmacokinetic-pharmacodynamic modeling, repeated small doses of a challenge
drug over a short time scale, and functional imaging to rapidly provide
quantitative estimates of drug sensitivity including EC50 (the concentration of
drug that produces half the maximum possible effect). We first test the method
with simulated data, assuming a typical sigmoidal dose-response curve and
assuming imperfect imaging that includes artifactual baseline signal drift and
random error. With these few assumptions, rapid quantitative pharmacodynamic
imaging reliably estimates EC50 from the simulated data, except when noise
overwhelms the drug effect or when the effect occurs only at high doses. In
preliminary fMRI studies of primate brain using a dopamine agonist, the
observed noise level is modest compared with observed drug effects, and a
quantitative EC50 can be obtained from some regional time-signal curves. Taken
together, these results suggest that research and clinical applications for
rapid quantitative pharmacodynamic imaging are realistic.


title: Blocks of affine quantum Schur algebras

abstract:
  The affine quantum Schur algebra is a certain important infinite dimensional
algebra whose representation theory is closely related to that of quantum
affine $\frak{gl}_n$. Finite dimensional irreducible modules for the affine
quantum Schur algebra ${\mathcal S}_{\vartriangle}(n,r)_{v}$ were classified in
\cite{DDF}, where $v\in{\mathbb C}^*$ is not a root of unity. We will classify
blocks of the affine quantum Schur algebra ${\mathcal
S}_{\vartriangle}(n,r)_{v}$ in this paper.


title: Prior-free and prior-dependent regret bounds for Thompson Sampling

abstract:
  We consider the stochastic multi-armed bandit problem with a prior
distribution on the reward distributions. We are interested in studying
prior-free and prior-dependent regret bounds, very much in the same spirit as
the usual distribution-free and distribution-dependent bounds for the
non-Bayesian stochastic bandit. Building on the techniques of Audibert and
Bubeck [2009] and Russo and Roy [2013] we first show that Thompson Sampling
attains an optimal prior-free bound in the sense that for any prior
distribution its Bayesian regret is bounded from above by $14 \sqrt{n K}$. This
result is unimprovable in the sense that there exists a prior distribution such
that any algorithm has a Bayesian regret bounded from below by $\frac{1}{20}
\sqrt{n K}$. We also study the case of priors for the setting of Bubeck et al.
[2013] (where the optimal mean is known as well as a lower bound on the
smallest gap) and we show that in this case the regret of Thompson Sampling is
in fact uniformly bounded over time, thus showing that Thompson Sampling can
greatly take advantage of the nice properties of these priors.


title:
Uncertainty Quantification of Discrete Association Problems in Image
  Sequence-based Tracking

abstract:
  Applications, ranging from tracking molecular motion within cells to
analyzing complex animal foraging behavior, require algorithms for associating
a collection of spot-like particles in one image with particles contained in
another image. These associations are often made via network flow algorithms.
However, it is often the case that many candidate association solutions (the
output of network flow algorithms) have nearly optimal scores; in this case,
the optimal assignment solution is of dubious quality. Algorithms for reliably
computing the uncertainty of candidate association solutions are
under-developed in situations where many particles are tracked over multiple
frames of data. This is due in part to the fact that exact uncertainty
quantification (UQ) in large association problems is computationally
intractable because the exact computation exhibits exponential dependence on
the number of particles tracked. We introduce a technique that can accurately
and efficiently quantify association ambiguity (i.e., UQ for discrete
association problems) without requiring the evaluation of the cost of each
feasible association solution. Our method can readily be wrapped around
existing tracking algorithms and can efficiently handle a variety of 2D
association problems. The applications presented are focused on tracking
molecules in live cells. Our method is validated via both simulations and
experiments. The experimental applications aim to accurately form tracks and
quantify diffusion of quantum dot labeled proteins from \emph{in vivo}
measurements; here association problems involving cost matrices possessing
hundreds to thousands of rows/columns are encountered. For such large-scale
problems, we discuss how our approach can efficiently and accurately quantify
inherent uncertainty in candidate data associations.


title:
On the existence of tight relative 2-designs on binary Hamming
  association schemes

abstract:
  It is known that there is a close analogy between "Euclidean t-designs vs.
spherical t-designs" and "Relative t-designs in binary Hamming association
schemes vs. combinatorial t-designs". In this paper, we want to prove how much
we can develop a similar theory in the latter situation, imitating the theory
in the former one. We first prove that the weight function is constant on each
shell for tight relative t-designs on p shells on a wide class of Q-polynomial
association schemes, including Hamming association schemes. In the theory of
Euclidean t-designs on 2 concentric spheres (shells), it is known that the
structure of coherent configurations is naturally attached. However, it seems
difficult to prove this claim in a general context. In the case of tight
2-designs in combinatorial 2-designs, there are great many tight 2-designs,
i.e., symmetric 2-designs, while there are very few tight 2e-designs for e no
less than 2. So, as a starting point, we concentrate our study to the existence
problem of tight relative 2-designs, in particular on 2 shells, in binary
Hamming association schemes H(n,2). We prove that every tight relative
2-designs on 2 shells in H(n,2) has the structure of coherent configuration. We
determined all the possible parameters of coherent configurations attached to
such tight relative 2-designs for n at most 30. Moreover for each of them we
determined whether there exists such a tight relative 2-design or not, either
by constructing them from symmetric 2-designs or Hadamard matrices, or
theoretically showing the non-existence. In particular, we show that for n
congruent to 6 (mod 8), there exist such tight relative 2-designs whose weight
functions are not constant. These are the first examples of those with
non-constant weight.


title:
Superconducting flux-flow type ultra-low-noise magnetic sensors - An
  alternative to dc-SQUIDs

abstract:
  A superconducting magnetometers based on the magnetic field dependence of the
Eck step voltage in long Josephson tunnel junctions (LJTJs) is demonstrated.
The field to be measured is applied perpendicular to a continuous
superconducting pickup loop. Wherever the loop has a narrow constriction, the
density of the flux-restoring circulating currents will become relatively high
and will locally create a magnetic field large enough to bring a biased LJTJ in
the flux-flow state, i.e., at a finite voltage proportional to the field
strength. This method allows the realization of a novel family of robust and
general-purpose superconducting devices which, despite their simplicity,
function as ultra-low-noise, wide-band and high-dynamics magnetometers. The
performances of low-T$_c$ sensor prototypes, among which a highly linear
voltage responsivity and a magnetic spectral density $S_B^{1/2}<
3\,fT/Hz^{1/2}$, promise to be competitive with those of the best
superconducting quantum interference devices.


title:
Change of the *congruence canonical form of 2-by-2 matrices under
  perturbations

abstract:
  We study how small perturbations of a 2-by-2 complex matrix can change its
canonical form for *congruence. We construct the Hasse diagram for the closure
ordering on the set of *congruence classes of 2-by-2 matrices.


title: A L\'evy-Khinchin formula for free groups

abstract:
  We find a L\'evy-Khinchin formula for radial functions on free groups. As a
corollary we obtain a linear bound on the growth of radial, conditionally
negative definite functions on free groups of two or more generators.


title:
Some Rigorous Results Relating Nonequilibrium, Equilibrium,
  Calorimetrically Measured and Residual Entropies during Cooling

abstract:
  We use rigorous nonequilibrium thermodynamic arguments to establish that (i)
the nonequilibrium entropy S(T_{0}) of any system is bounded below by the
experimentally (calorimetrically) determined entropy S_{expt}(T_{0}), (ii)
S_{expt}(T_{0}) is bounded below by the equilibrium or stationary state (such
as the supercooled liquid) entropy S_{SCL}(T_{0}) and consequently (iii)
S(T_{0}) cannot drop below S_{SCL}(T_{0}). It then follows that the residual
entropy S_{R} is bounded below by the extrapolated S_{expt}(0)>S_{SCL}(0) at
absolute zero. These results are very general and applicable to all
nonequilibrium systems regardless of how far they are from their stationary
states.


title: Prime differential nilalgebra exists

abstract:
  We construct a monomorphism from the differential algebra $k\{x\} / [x^m]$ to
a Grassmann algebra endowed with a structure of differential algebra. Using
this monomorphism we prove primality of $k\{x\} / [x^m]$ and its algebra of
differential polynomials, solve one of Ritt's problems and give a new proof of
integrality of the ideal $[x^m]$.


title: Comparison of shell model results for even-even Se isotopes

abstract:
  Comprehensive set of shell model calculations for $^{78-84}$Se isotopes have
been performed with recently derived interactions, namely JUN45 and jj44b for
${f_{5/2}pg_{9/2}}$ space. To study the importance of the proton excitations
across Z=28 shell in this region mentioned by Cheal {\it et al.} [Phys. Rev.
Lett. {\bf104}, 252502 (2010)], calculation for ${fpg_{9/2}}$ valence space
using an ${fpg}$ effective interaction with $^{48}$Ca as core and imposing a
truncation has also been performed. Comparison of the calculations with
experimental data show that the predicted results of jj44b interaction are in
good agreement with experimental data.


title: Cohomology of n-ary-Nambu-Lie superalgebras and super_1 3-algebra

abstract:
  The purpose of this paper is define the representation and the cohomology of
n-ary-Nambu-Lie superalgebras. Morever we study extensions and provide the
computation of the derivations and second cohomology group of super w_1
3-algebra


title:
Derivative-Free Estimation of the Score Vector and Observed Information
  Matrix with Application to State-Space Models

abstract:
  Ionides, King et al. (see e.g. Inference for nonlinear dynamical systems,
PNAS 103) have recently introduced an original approach to perform maximum
likelihood parameter estimation in state-space models which only requires being
able to simulate the latent Markov model according to its prior distribution.
Their methodology relies on an approximation of the score vector for general
statistical models based upon an artificial posterior distribution and bypasses
the calculation of any derivative. We show here that this score estimator can
be derived from a simple application of Stein's lemma and how an additional
application of this lemma provides an original derivative-free estimator of the
observed information matrix. We establish that these estimators exhibit
robustness properties compared to finite difference estimators while their bias
and variance scale as well as finite difference type estimators, including
simultaneous perturbations (see e.g. Spall, IEEE Trans. on Automatic Control
37), with respect to the dimension of the parameter. For state-space models
where sequential Monte Carlo computation is required, these estimators can be
further improved. In this specific context, we derive original derivative-free
estimators of the score vector and observed information matrix which are
computed using sequential Monte Carlo approximations of smoothed additive
functionals associated with a modified version of the original state-space
model.


title:
Rescattering effects in proton interaction with light neutron rich
  nuclei

abstract:
  Within the framework of the Glauber diffraction theory, the differential
cross sections of the elastic p6He, p8Li, and p9Li scattering were calculated
at intermediate energies from 70 to 1000 MeV/nucleon. The use of realistic
three-body wave functions alpha-n-n (6He), alpha-t-n (8Li) and alpha-t-2n
(9Li), obtained in the framework of modern clear models, and the expansion of
the Glauber operator into a series of multiple scatterings in a form that is
well adapted to the three-body nuclei configuration, allows the calculation of
the matrix elements, by taking into account the rescattering from all structure
components of the designated nuclei.


title: On the character variety of the four-holed sphere

abstract:
  We study the (relative) SL(2,C) character varieties of the four-holed sphere
and the action of the mapping class group on it. We describe a domain of
discontinuity for this action, and, in the case of real characters, show that
this domain of discontinuity may be non-empty on the components where the
relative euler class is non-maximal.


title: New aspects of symmetry of elementary cellular automata

abstract:
  We present a new classification of elementary cellular automata. It is based
on the structure of the network of states, connected with the transitions
between them; the latter are determined by the automaton rule. Recently an
algorithm has been proposed to compress the network of states (M. J. Krawczyk,
Physica A 390 (2011) 2181). In this algorithm, states are grouped into classes,
according to the local symmetry of the network. In the new classification, an
automaton is described by the number of classes #(N) as dependent on the system
size N. In most cases, the results reflect the known classification into 88
groups. However, the function #(N) also appears to be the same for some rules
which have not been grouped together yet. In this way, the automaton 23 is
equivalent to 232, 77 to 178, 105 to 150, the pair (43, 113) to the pair (142,
212) and the group (12, 68, 207, 221) to the group (34, 48, 187, 243).
Furthermore, automata 51, 204, the pair (15, 85) and the pair (170,240) are all
mutually equivalent. Results are also presented on the structure of networks of
states.


title: Singular 2 webs and Polar Curves

abstract:
  A 2-web in the plane is given by two everywhere transverse 1-foliations. In
this paper we introduce the study of singular 2-webs, given by any two
foliations, which may be tangent in some points. We show that such two
foliations are tangent along a curve, which will be called the polar curve of
the 2-web, and we study the relationship between the contact order of leaves of
both foliations and the singularities of the polar curve.


title: Graph isomorphism and adiabatic quantum computing

abstract:
  In the Graph Isomorphism problem two N-vertex graphs G and G' are given and
the task is to determine whether there exists a permutation of the vertices of
G that preserves adjacency and transforms G into G'. If yes, then G and G' are
said to be isomorphic; otherwise they are non-isomorphic. The GI problem is an
important problem in computer science and is thought to be of comparable
difficulty to integer factorization. In this paper we present a quantum
algorithm that solves arbitrary instances of GI and can also determine all
automorphisms of a given graph. We show how the GI problem can be converted to
a combinatorial optimization problem that can be solved using adiabatic quantum
evolution. We numerically simulate the algorithm's quantum dynamics and show
that it correctly: (i) distinguishes non-isomorphic graphs; (ii) recognizes
isomorphic graphs; and (iii) finds all automorphisms of a given graph G. We
then discuss the GI quantum algorithm's experimental implementation, and close
by showing how it can be leveraged to give a quantum algorithm that solves
arbitrary instances of the NP-Complete Sub-Graph Isomorphism problem.


title: On the probability of being synchronizable

abstract:
  We prove that a random automaton with $n$ states and any fixed non-singleton
alphabet is synchronizing with high probability. Moreover, we also prove that
the convergence rate is exactly $1-\Theta(\frac{1}{n})$ as conjectured by
Cameron \cite{CamConj} for the most interesting binary alphabet case. Finally,
we describe a deterministic algorithm which decides whether a given random
automaton is synchronizing in linear expected time.


title:
Points fattening on P^1 x P^1 and symbolic powers of bi-homogeneous
  ideals

abstract:
  We study symbolic powers of bi-homogeneous ideals of points in the Cartesian
product of two projective lines and extend to this setting results on the
effect of points fattening obtained by Bocci, Chiantini and Dumnicki, Szemberg,
Tutaj-Gasi\'nska. We prove a Chudnovsky-type theorem for bi-homogeneous ideals
and apply it to classification of configurations of points with minimal or no
fattening effect. We hope that the ideas developed in this project will find
further algebraic and geometric applications e.g. to study similar problems on
arbitrary surfaces.


title:
The derivation of Swarming models: Mean-Field Limit and Wasserstein
  distances

abstract:
  These notes are devoted to a summary on the mean-field limit of large
ensembles of interacting particles with applications in swarming models. We
first make a summary of the kinetic models derived as continuum versions of
second order models for swarming. We focus on the question of passing from the
discrete to the continuum model in the Dobrushin framework. We show how to use
related techniques from fluid mechanics equations applied to first order models
for swarming, also called the aggregation equation. We give qualitative bounds
on the approximation of initial data by particles to obtain the mean-field
limit for radial singular (at the origin) potentials up to the Newtonian
singularity. We also show the propagation of chaos for more restricted set of
singular potentials.


title: Improved bounds for reduction to depth 4 and depth 3

abstract:
  Koiran showed that if a $n$-variate polynomial of degree $d$ (with
$d=n^{O(1)}$) is computed by a circuit of size $s$, then it is also computed by
a homogeneous circuit of depth four and of size
$2^{O(\sqrt{d}\log(d)\log(s))}$. Using this result, Gupta, Kamath, Kayal and
Saptharishi gave a $\exp(O(\sqrt{d\log(d)\log(n)\log(s)}))$ upper bound for the
size of the smallest depth three circuit computing a $n$-variate polynomial of
degree $d=n^{O(1)}$ given by a circuit of size $s$.
  We improve here Koiran's bound. Indeed, we show that if we reduce an
arithmetic circuit to depth four, then the size becomes
$\exp(O(\sqrt{d\log(ds)\log(n)}))$. Mimicking Gupta, Kamath, Kayal and
Saptharishi's proof, it also implies the same upper bound for depth three
circuits.
  This new bound is not far from optimal in the sense that Gupta, Kamath, Kayal
and Saptharishi also showed a $2^{\Omega(\sqrt{d})}$ lower bound for the size
of homogeneous depth four circuits such that gates at the bottom have fan-in at
most $\sqrt{d}$. Finally, we show that this last lower bound also holds if the
fan-in is at least $\sqrt{d}$.


title: Topological Strings, D-Model, and Knot Contact Homology

abstract:
  We study the connection between topological strings and contact homology
recently proposed in the context of knot invariants. In particular, we
establish the proposed relation between the Gromov-Witten disk amplitudes of a
Lagrangian associated to a knot and augmentations of its contact homology
algebra. This also implies the equality between the Q-deformed A-polynomial and
the augmentation polynomial of knot contact homology (in the irreducible case).
We also generalize this relation to the case of links and to higher rank
representations for knots. The generalization involves a study of the quantum
moduli space of special Lagrangian branes with higher Betti numbers probing the
Calabi-Yau. This leads to an extension of SYZ, and a new notion of mirror
symmetry, involving higher dimensional mirrors. The mirror theory is a
topological string, related to D-modules, which we call the "D-model." In the
present setting, the mirror manifold is the augmentation variety of the link.
Connecting further to contact geometry, we study intersection properties of
branches of the augmentation variety guided by the relation to D-modules. This
study leads us to propose concrete geometric constructions of Lagrangian
fillings for links. We also relate the augmentation variety with the large N
limit of the colored HOMFLY, which we conjecture to be related to a
Q-deformation of the extension of A-polynomials associated with the link
complement.


title: Pairings from a tensor product point of view

abstract:
  Pairings are particular bilinear maps, and as any bilinear maps they factor
through the tensor product as group homomorphisms. Besides, nothing seems to
prevent us to construct pairings on other abelian groups than elliptic curves
or more general abelian varieties. The point of view adopted in this
contribution is based on these two observations. Thus we present an elliptic
curve free study of pairings which is essentially based on tensor products of
abelian groups (or modules). Tensor products of abelian groups are even
explicitly computed under finiteness conditions. We reveal that the existence
of pairings depends on the non-degeneracy of some universal bilinear map,
called the canonical bilinear map. In particular it is shown that the
construction of a pairing on $A\times A$ is always possible whatever a finite
abelian group $A$ is. We also propose some new constructions of pairings, one
of them being based on the notion of group duality which is related to the
concept of non-degeneracy.


title:
On a consistent macroscopic description for a spin quantum plasma with
  interparticle interactions

abstract:
  Quantum mechanical averaging of the particle concentration operator is an
effective starting point for derivation of the many-particle quantum
hydrodynamic equations. In many-particle quantum systems, we have to separate
the ordered motion of the local center of mass (velocity field), the thermal,
and the quantum motion. The quantum mechanical average process, invoked here,
is completely determined, and is different from the usual averaging processes
that introduces undefined probabilities for quantum states. It is shown that
the Madelung decomposition for the $N$-particle spinor wave function allows the
correct introduction of the velocity field, and gives explicit expressions for
the quantum contributions to both the momentum, and the spin flux. The
formalism also contains plasma effects produced by the Coulomb and spin-spin
interparticle interactions. It is shown that both interactions appear in plasma
dynamics as effective electric and magnetic fields. As result we find a fully
coherent description for spin quantum plasma in the self-consistent field
approximation for interparticle interactions. A simple consequence - the change
brought about by interparticle correlations on the propagation of electrostatic
waves in a spin quantum plasma - is discussed.


title: n-particle quantum statistics on graphs

abstract:
  We develop a full characterization of abelian quantum statistics on graphs.
We explain how the number of anyon phases is related to connectivity. For
2-connected graphs the independence of quantum statistics with respect to the
number of particles is proven. For non-planar 3-connected graphs we identify
bosons and fermions as the only possible statistics, whereas for planar
3-connected graphs we show that one anyon phase exists. Our approach also
yields an alternative proof of the structure theorem for the first homology
group of n-particle graph configuration spaces. Finally, we determine the
topological gauge potentials for 2-connected graphs.


title:
High-frequency homogenization of zero frequency stop band photonic and
  phononic crystals

abstract:
  We present an accurate methodology for representing the physics of waves, for
periodic structures, through effective properties for a replacement bulk
medium: This is valid even for media with zero frequency stop-bands and where
high frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low
frequency (or quasi-static) behaviour has been neatly encapsulated in effective
anisotropic media. However such classical homogenization theories break down in
the high-frequency or stop band regime.
  Higher frequency phenomena are of significant importance in photonics
(transverse magnetic waves propagating in infinite conducting parallel fibers),
phononics (anti-plane shear waves propagating in isotropic elastic materials
with inclusions), and platonics (flexural waves propagating in thin-elastic
plates with holes). Fortunately, the recently proposed high-frequency
homogenization (HFH) theory is only constrained by the knowledge of standing
waves in order to asymptotically reconstruct dispersion curves and associated
Floquet-Bloch eigenfields: It is capable of accurately representing
zero-frequency stop band structures. The homogenized equations are partial
differential equations with a dispersive anisotropic homogenized tensor that
characterizes the effective medium.
  We apply HFH to metamaterials, exploiting the subtle features of Bloch
dispersion curves such as Dirac-like cones, as well as zero and negative group
velocity near stop bands in order to achieve exciting physical phenomena such
as cloaking, lensing and endoscope effects. These are simulated numerically
using finite elements and compared to predictions from HFH. An extension of HFH
to periodic supercells enabling complete reconstruction of dispersion curves
through an unfolding technique is also introduced.


title:
Measurement of masses in the t t-bar system by kinematic endpoints in pp
  collisions at sqrt(s) = 7 TeV

abstract:
  A simultaneous measurement of the top-quark, W-boson, and neutrino masses is
reported for t t-bar events selected in the dilepton final state from a data
sample corresponding to an integrated luminosity of 5.0 inverse femtobarns
collected by the CMS experiment in pp collisions at sqrt(s) = 7 TeV. The
analysis is based on endpoint determinations in kinematic distributions. When
the neutrino and W-boson masses are constrained to their world-average values,
a top-quark mass value of M[t] = 173.9 +/- 0.9 (stat.) +1.7/-2.1 (syst.) GeV is
obtained. When such constraints are not used, the three particle masses are
obtained in a simultaneous fit. In this unconstrained mode the study serves as
a test of mass determination methods that may be used in beyond standard model
physics scenarios where several masses in a decay chain may be unknown and
undetected particles lead to underconstrained kinematics.


title: Optimal Transport with Proximal Splitting

abstract:
  This article reviews the use of first order convex optimization schemes to
solve the discretized dynamic optimal transport problem, initially proposed by
Benamou and Brenier. We develop a staggered grid discretization that is well
adapted to the computation of the $L^2$ optimal transport geodesic between
distributions defined on a uniform spatial grid. We show how proximal splitting
schemes can be used to solve the resulting large scale convex optimization
problem. A specific instantiation of this method on a centered grid corresponds
to the initial algorithm developed by Benamou and Brenier. We also show how
more general cost functions can be taken into account and how to extend the
method to perform optimal transport on a Riemannian manifold.


title: A Remark on the Reeb Flow for Spheres

abstract:
  We prove the non--triviality of the Reeb flow for the (2n+1)--dimensional
standard contact spheres inside the fundamental group of their contactomorphism
group, n greater than 3. The argument uses the existence of homotopically
non--trivial 2--spheres in the space of contact structures of a 3--Sasakian
manifold.


title:
van der Waals Interaction Energy Between Two Atoms Moving With Uniform
  Acceleration

abstract:
  We consider the interatomic van der Waals interaction energy between two
neutral ground-state atoms moving in the vacuum space with the same uniform
acceleration. We assume the acceleration orthogonal to their separation, so
that their mutual distance remains constant. Using a model for the van der
Waals dispersion interaction based on the interaction between the instantaneous
atomic dipole moments, which are induced and correlated by the zero-point field
fluctuations, we evaluate the interaction energy between the two accelerating
atoms in terms of quantities expressed in the laboratory reference frame. We
find that the dependence of the van der Waals interaction between the atoms
from the distance is different with respect to the case of atoms at rest, and
the relation of our results with the Unruh effect is discussed. We show that in
the near zone a new term proportional to $R^{-5}$ adds to the usual $R^{-6}$
behavior, and in the far zone a term proportional to $R^{-6}$ adds to the usual
$R^{-7}$ behavior, making the interaction of a longer range. We also find that
the interaction energy is time-dependent, and the physical meaning of this
result is discussed. In particular, we find acceleration-dependent corrections
to the $R^{-7}$ (far zone) and $R^{-6}$ (near zone) proportional to
$a^2t^2/c^2$; this suggests that significant changes to the van der Waals
interaction between the atoms could be obtained if sufficiently long times are
taken, without necessity of the extremely high accelerations required by other
known manifestations of the Unruh effect.


title: Composition and decomposition of indestructible Blaschke products

abstract:
  We prove that the composition of two indestructible Blaschke products is
again an indestructible Blaschke product. We also show that if an
indestructible Blaschke product is the composition of two bounded analytic
functions, then both functions are indestructible Blaschke products.


title:
Resolving galaxies in time and space: I: Applying STARLIGHT to CALIFA
  data cubes

abstract:
  Fossil record methods based on spectral synthesis techniques have matured
over the past decade, and their application to integrated galaxy spectra
fostered substantial advances on the understanding of galaxies and their
evolution. Yet, because of the lack of spatial resolution, these studies are
limited to a global view, providing no information about the internal physics
of galaxies. Motivated by the CALIFA survey, which is gathering Integral Field
Spectroscopy over the full optical extent of 600 galaxies, we have developed an
end-to-end pipeline which: (i) partitions the observed data cube into Voronoi
zones in order to, when necessary and taking due account of correlated errors,
increase the S/N, (ii) extracts spectra, including propagated errors and
bad-pixel flags, (iii) feeds the spectra into the STARLIGHT spectral synthesis
code, (iv) packs the results for all galaxy zones into a single file, (v)
performs a series of post-processing operations, including zone-to-pixel image
reconstruction and unpacking the spectral and stellar population properties
into multi-dimensional time, metallicity, and spatial coordinates. This paper
provides an illustrated description of this whole pipeline and its products.
Using data for the nearby spiral NGC 2916 as a show case, we go through each of
the steps involved, presenting ways of visualizing and analyzing this manifold.
These include 2D maps of properties such as the v-field, stellar extinction,
mean ages and metallicities, mass surface densities, star formation rates on
different time scales and normalized in different ways, 1D averages in the
temporal and spatial dimensions, projections of the stellar light and mass
growth (x,y,t) cubes onto radius-age diagrams, etc. The results illustrate the
richness of the combination of IFS data with spectral synthesis, providing a
glimpse of what is to come from CALIFA and future surveys. (Abridged)


title: Hypercontractivity in group von Neumann algebras

abstract:
  In this paper, we provide a combinatorial/numerical method to establish new
hypercontractivity estimates in group von Neumann algebras. We will illustrate
our method with free groups, triangular groups and finite cyclic groups, for
which we shall obtain optimal time hypercontractive $L_2 \to L_q$ inequalities
with respect to the Markov process given by the word length and with $q$ an
even integer. Interpolation and differentiation also yield general $L_p \to
L_q$ hypercontrativity for $1 < p \le q < \infty$ via logarithmic Sobolev
inequalities. Our method admits further applications to other discrete groups
without small loops as far as the numerical part ---which varies from one group
to another--- is implemented and tested in a computer. We also develop another
combinatorial method which does not rely on computational estimates and
provides (non-optimal) $L_p \to L_q$ hypercontractive inequalities for a larger
class of groups/lengths, including any finitely generated group equipped with a
conditionally negative word length, like infinite Coxeter groups. Our second
method also yields hypercontractivity bounds for groups admitting a finite
dimensional proper cocycle. Hypercontractivity fails for conditionally negative
lengths in groups satisfying Kazhdan property (T).


title:
Gaussian Half-Duplex Relay Networks: improved constant gap and
  connections with the assignment problem

abstract:
  This paper considers a general Gaussian relay network where a source
transmits a message to a destination with the help of N half-duplex relays. It
proves that the information theoretic cut-set upper bound to the capacity can
be achieved to within 2:021(N +2) bits with noisy network coding, thereby
reducing the previously known gap. Further improved gap results are presented
for more structured networks like diamond networks. It is then shown that the
generalized Degrees-of-Freedom of a general Gaussian half-duplex relay network
is the solution of a linear program, where the coefficients of the linear
inequality constraints are proved to be the solution of several linear
programs, known in graph theory as the assignment problem, for which efficient
numerical algorithms exist. The optimal schedule, that is, the optimal value of
the 2^N possible transmit-receive configurations/states for the relays, is
investigated and known results for diamond networks are extended to general
relay networks. It is shown, for the case of 2 relays, that only 3 out of the 4
possible states have strictly positive probability. Extensive experimental
results show that, for a general N-relay network with N<9, the optimal schedule
has at most N +1 states with strictly positive probability. As an extension of
a conjecture presented for diamond networks, it is conjectured that this result
holds for any HD relay network and any number of relays. Finally, a 2-relay
network is studied to determine the channel conditions under which selecting
the best relay is not optimal, and to highlight the nature of the rate gain due
to multiple relays.


title:
The effect of second generation populations on the integrated colors of
  metal-rich globular clusters in early-type galaxies

abstract:
  The mean color of globular clusters (GCs) in early-type galaxies is in
general bluer than the integrated color of halo field stars in host galaxies.
Metal-rich GCs often appear more associated with field stars than metal-poor
GCs, yet show bluer colors than their host galaxy light. Motivated by the
discovery of multiple stellar populations in Milky Way GCs, we present a new
scenario in which the presence of second-generation (SG) stars in GCs is
responsible for the color discrepancy between metal-rich GCs and field stars.
The model assumes that the SG populations have enhanced helium abundance as
evidenced by observations, and it gives a good explanation of the bluer optical
colors of metal-rich GCs than field stars as well as strong Balmer lines and
blue UV colors of metal-rich GCs. Ours may be complementary to the recent
scenario suggesting the difference in stellar mass functions (MFs) as an origin
for the GC-to-star color offset. A quantitative comparison is given between the
SG and MF models.


title: Generation of Primordial Magnetic Fields on Linear Over-density Scales

abstract:
  Magnetic fields appear to be present in all galaxies and galaxy clusters.
Recent measurements indicate that a weak magnetic field may be present even in
the smooth low density intergalactic medium. One explanation for these
observations is that a seed magnetic field was generated by some unknown
mechanism early in the life of the Universe, and was later amplified by various
dynamos in nonlinear objects like galaxies and clusters. We show that a
primordial magnetic field is expected to be generated in the early Universe on
purely linear scales through vorticity induced by scale-dependent temperature
fluctuations or equivalently, a spatially varying speed of sound of the gas.
Residual free electrons left over after recombination tap into this vorticity
to generate magnetic field via the Biermann battery process. Although the
battery operates even in the absence of any relative velocity between dark
matter and gas at the time of recombination, the presence of such a relative
velocity modifies the predicted spatial power spectrum of the magnetic field.
At redshifts of order a few tens, we estimate a root mean square field strength
of order 1e-25 -1e-24 G on comoving scales~10 kpc. This field, which is
generated purely from linear perturbations, is expected to be amplified
significantly after reionization, and to be further boosted by dynamo processes
during nonlinear structure formation.


title: Continuum armed bandit problem of few variables in high dimensions

abstract:
  We consider the stochastic and adversarial settings of continuum armed
bandits where the arms are indexed by [0,1]^d. The reward functions r:[0,1]^d
-> R are assumed to intrinsically depend on at most k coordinate variables
implying r(x_1,..,x_d) = g(x_{i_1},..,x_{i_k}) for distinct and unknown
i_1,..,i_k from {1,..,d} and some locally Holder continuous g:[0,1]^k -> R with
exponent 0 < alpha <= 1. Firstly, assuming (i_1,..,i_k) to be fixed across
time, we propose a simple modification of the CAB1 algorithm where we construct
the discrete set of sampling points to obtain a bound of
O(n^((alpha+k)/(2*alpha+k)) (log n)^((alpha)/(2*alpha+k)) C(k,d)) on the
regret, with C(k,d) depending at most polynomially in k and sub-logarithmically
in d. The construction is based on creating partitions of {1,..,d} into k
disjoint subsets and is probabilistic, hence our result holds with high
probability. Secondly we extend our results to also handle the more general
case where (i_1,...,i_k) can change over time and derive regret bounds for the
same.


title:
Uniaxial pressure effect on structural and magnetic phase transitions in
  NaFeAs and its comparison with as-grown and annealed BaFe$_2$As$_2$

abstract:
  We use neutron scattering to study the effect of uniaxial pressure on the
tetragonal-to-orthorhombic structural ($T_s$) and
paramagnetic-to-antiferromagnetic ($T_N$) phase transitions in NaFeAs and
compare the outcome with similar measurements on as-grown and annealed
BaFe$_2$As$_2$. In previous work on as-grown BaFe$_2$As$_2$, uniaxial pressure
necessary to detwin the sample was found to induce a significant increase in
zero pressure $T_N$ and $T_s$. However, we find that similar uniaxial pressure
used to detwin NaFeAs and annealed BaFe$_2$As$_2$ has a very small effect on
their $T_N$ and $T_s$.Since transport measurements on these samples still
reveal resistivity anisotropy above $T_N$ and $T_s$, we conclude that such
anisotropy cannot be due to uniaxial strain induced $T_N$ and $T_s$ shifts, but
must arise from intrinsic electronic anisotropy in these materials.


title: Tests of Lorentz invariance: a 2013 update

abstract:
  We present an updated review of Lorentz invariance tests in Effective field
theories (EFT) in the matter as well as in the gravity sector. After a general
discussion of the role of Lorentz invariance and a derivation of its
transformations along the so called von Ignatovski theorem, we present the
dynamical frameworks developed within local EFT and the available constraints
on the parameters governing the Lorentz breaking effects. In the end, we
discuss two specific examples, the OPERA "affaire" and the case of
Ho\v{r}ava-Lifshitz gravity. The first case will serve as an example, and a
caveat, of the practical application of the general techniques developed for
constraining Lorentz invariance violation (LIV) to a direct observation
potentially showing these effects. The second case will show how the
application of the same techniques to a specific quantum gravity scenario has
far fetching implications not foreseeable in a purely phenomenological EFT
approach.


title:
Local Null Controllability of a Chemotaxis System of Parabolic-Elliptic
  Type

abstract:
  In this paper, we are concerned with the controllability of a chemotaxis
system of parabolic-elliptic type. By linearizing the nonlinear system into two
separated linear equations to bypass the obstacle caused by the nonlinear drift
term, we establish the local null controllability of the original nonlinear
system. The approach is different from the usual way of treating the coupled
parabolic systems.


title: A note on stability and Cauchy time functions

abstract:
  Since the solution of the so-called folk problems of smoothability, there has
been a special interest in the properties of classical time and volume
functions of spacetimes. Here we supply some information that complements the
one provided in arXiv:1108.5120v3 and arXiv:1301.2909v1, and discuss some
results. As an illustration, we show that any Cauchy temporal function for a
globally hyperbolic spacetime remains Cauchy temporal for close metrics
---which, in particular, implies stability for global hyperbolicity.


title: Cardinality of $\ell_1$-Segments and Genocchi Numbers

abstract:
  We prove that the Genocchi numbers of first and second kind give the
cardinality of certain segments in permutation spaces, with respect to the
$\ell_1$-distance. Experimental data suggests that those segments have maximal
cardinality among all segments in the corresponding spaces.


title: Request Complexity of VNet Topology Extraction: Dictionary-Based Attacks

abstract:
  The network virtualization paradigm envisions an Internet where arbitrary
virtual networks (VNets) can be specified and embedded over a shared substrate
(e.g., the physical infrastructure). As VNets can be requested at short notice
and for a desired time period only, the paradigm enables a flexible service
deployment and an efficient resource utilization.
  This paper investigates the security implications of such an architecture. We
consider a simple model where an attacker seeks to extract secret information
about the substrate topology, by issuing repeated VNet embedding requests. We
present a general framework that exploits basic properties of the VNet
embedding relation to infer the entire topology. Our framework is based on a
graph motif dictionary applicable for various graph classes. Moreover, we
provide upper bounds on the request complexity, the number of requests needed
by the attacker to succeed.


title:
One-dimensional perturbations of unbounded selfadjoint operators with
  empty spectrum

abstract:
  We study spectral properties of one-dimensional singular perturbations of an
unbounded selfadjoint operator and give criteria for the possibility to remove
the whole spectrum by a perturbation of this type. A counterpart of our results
for the case of bounded operators provides a complete description of compact
selfadjoint operators whose rank one perturbation is a Volterra operator.


title:
The Armstrong-Frederick cyclic hardening plasticity model with Cosserat
  effects

abstract:
  We propose an extension of the cyclic hardening plasticity model formulated
by Armstrong and Frederick which includes micropolar effects. Our micropolar
extension establishes coercivity of the model which is otherwise not present.
We study then existence of solutions to the quasistatic, rate-independent
Armstrong-Frederick model with Cosserat effects which is, however, still of
non-monotone, non-associated type. In order to do this, we need to relax the
pointwise definition of the flow rule into a suitable weak energy-type
inequality. It is shown that the limit in the Yosida approximation process
satisfies this new solution concept. The limit functions have a better
regularity than previously known in the literature, where the original
Armstrong-Frederick model has been studied.


title: Nonlinear Basis Pursuit

abstract:
  In compressive sensing, the basis pursuit algorithm aims to find the sparsest
solution to an underdetermined linear equation system. In this paper, we
generalize basis pursuit to finding the sparsest solution to higher order
nonlinear systems of equations, called nonlinear basis pursuit. In contrast to
the existing nonlinear compressive sensing methods, the new algorithm that
solves the nonlinear basis pursuit problem is convex and not greedy. The novel
algorithm enables the compressive sensing approach to be used for a broader
range of applications where there are nonlinear relationships between the
measurements and the unknowns.


title: Pulsar State Switching from Markov Transitions and Stochastic Resonance

abstract:
  Markov processes are shown to be consistent with metastable states seen in
pulsar phenomena, including intensity nulling, pulse-shape mode changes,
subpulse drift rates, spindown rates, and X-ray emission, based on the
typically broad and monotonic distributions of state lifetimes. Markovianity
implies a nonlinear magnetospheric system in which state changes occur
stochastically, corresponding to transitions between local minima in an
effective potential. State durations (though not transition times) are thus
largely decoupled from the characteristic time scales of various magnetospheric
processes. Dyadic states are common but some objects show at least four states
with some transitions forbidden. Another case is the long-term intermittent
pulsar B1931+24 that has binary radio-emission and torque states with wide, but
non-monotonic duration distributions. It also shows a quasi-period of $38\pm5$
days in a 13-yr time sequence, suggesting stochastic resonance in a Markov
system with a forcing function that could be strictly periodic or
quasi-periodic. Nonlinear phenomena are associated with time-dependent activity
in the acceleration region near each magnetic polar cap. The polar-cap diode is
altered by feedback from the outer magnetosphere and by return currents from an
equatorial disk that may also cause the neutron star to episodically charge and
discharge. Orbital perturbations in the disk provide a natural periodicity for
the forcing function in the stochastic resonance interpretation of B1931+24.
Disk dynamics may introduce additional time scales in observed phenomena.
Future work can test the Markov interpretation, identify which pulsar types
have a propensity for state changes, and clarify the role of selection effects.


title: Tight Bounds on the Synthesis of 3-bit Reversible Circuits: NFT Library

abstract:
  The reversible circuit synthesis problem can be reduced to permutation group.
This allows Schreier-Sims Algorithm for the strong generating set-finding
problem to be used to find tight bounds on the synthesis of 3-bit reversible
circuits using the NFT library. The tight bounds include the maximum and
minimum length of 3-bit reversible circuits, the maximum and minimum cost of
3-bit reversible circuits. The analysis shows better results than that found in
the literature for the lower bound of the cost. The analysis also shows that
there are 1960 universal reversible sub-libraries from the main NFT library.


title: On the Seismicity of September 7, 2011 X1.8-class Flare

abstract:
  We present results of our preliminary analysis of acoustically active X-class
flare of September 7, 2011. We report two acoustic sources detected via
acoustic holography and verified by finding a ridge in time-distance diagrams.
We compare the directional information extracted from time-distance and
acoustic holography, showing a good agreement in this case. We report that the
direction where amplitude of the wave-front is the largest lies through the
strong magnetic field and sunspot, suggesting that absorption of the acoustic
wave power by magnetic field can be ruled out as a wave anisotropy mechanism in
this case.


title: Fully Automated Shape Analysis Based on Forest Automata

abstract:
  Forest automata (FA) have recently been proposed as a tool for shape analysis
of complex heap structures. FA encode sets of tree decompositions of heap
graphs in the form of tuples of tree automata. In order to allow for
representing complex heap graphs, the notion of FA allowed one to provide
user-defined FA (called boxes) that encode repetitive graph patterns of shape
graphs to be used as alphabet symbols of other, higher-level FA. In this paper,
we propose a novel technique of automatically learning the FA to be used as
boxes that avoids the need of providing them manually. Further, we propose a
significant improvement of the automata abstraction used in the analysis. The
result is an efficient, fully-automated analysis that can handle even as
complex data structures as skip lists, with the performance comparable to
state-of-the-art fully-automated tools based on separation logic, which,
however, specialise in dealing with linked lists only.


title:
UM 625 Revisited: Multiwavelength Study of A Seyfert 1 Galaxy with a
  Low-mass Black Hole

abstract:
  UM 625, previously identified as a narrow-line active galactic nucleus (AGN),
actually exhibits broad \ha\ and \hb\ lines whose width and luminosity indicate
a low black hole mass of $1.6 \times 10^6$ \msun. We present a detailed
multiwavelength study of the nuclear and host galaxy properties of UM 625.
Analysis of \chandra\ and \xmm\ observations suggests that this system contains
a heavily absorbed and intrinsically X-ray weak ($\aox=-1.72$) nucleus.
Although not strong enough to qualify as radio-loud, UM 625 does belong to a
minority of low-mass AGNs detected in the radio. The broad-band spectral energy
distribution constrains the bolometric luminosity to
$\lbol\approx(0.5-3)\times10^{43}$ \lum\ and $\lratio\approx0.02-0.15$. A
comprehensive analysis of Sloan Digital Sky Survey and {\it Hubble Space
Telescope}\ images shows that UM 625 is a nearly face-on S0 galaxy with a
prominent, relatively blue pseudobulge (\sersic\ index $n = 1.60$) that
accounts for $\sim$60% of the total light in the $R$ band. The extended disk is
featureless, but the central $\sim150-400$ pc contains a conspicuous semi-ring
of bright, blue star-forming knots, whose integrated ultraviolet luminosity
suggests a star formation rate of $\sim$0.3 \msun yr$^{-1}$. The mass of the
central black hole roughly agrees with the value predicted from its bulge
velocity dispersion but is significantly lower than that expected from its
bulge luminosity.


title: Improved Complexity Results on $k$-Coloring $P_t$-Free Graphs

abstract:
  A graph is $H$-free if it does not contain an induced subgraph isomorphic to
$H$. We denote by $P_k$ and $C_k$ the path and the cycle on $k$ vertices,
respectively. In this paper, we prove that 4-COLORING is NP-complete for
$P_7$-free graphs, and that 5-COLORING is NP-complete for $P_6$-free graphs.
These two results improve all previous results on $k$-coloring $P_t$-free
graphs, and almost complete the classification of complexity of $k$-COLORING
$P_t$-free graphs for $k\ge 4$ and $t\ge 1$, leaving as the only missing case
4-COLORING $P_6$-free graphs. We expect that 4-COLORING is polynomial time
solvable for $P_6$-free graphs; in support of this, we describe a polynomial
time algorithm for 4-COLORING $P_6$-free graphs which are also $P$-free, where
$P$ is the graph obtained from $C_4$ by adding a new vertex and making it
adjacent to exactly one vertex on the $C_4$.


title: Plane mixed discriminants and toric jacobians

abstract:
  Polynomial algebra offers a standard approach to handle several problems in
geometric modeling. A key tool is the discriminant of a univariate polynomial,
or of a well-constrained system of polynomial equations, which expresses the
existence of a multiple root. We concentrate on bivariate polynomials and
establish an original formula that relates the mixed discriminant of two
bivariate Laurent polynomials with fixed support, with the sparse resultant of
these polynomials and their toric Jacobian. This allows us to obtain a new
proof for the bidegree of the mixed discriminant as well as to establish
multipicativity formulas arising when one polynomial can be factored.


title: Exchanging OWL 2 QL Knowledge Bases

abstract:
  Knowledge base exchange is an important problem in the area of data exchange
and knowledge representation, where one is interested in exchanging information
between a source and a target knowledge base connected through a mapping. In
this paper, we study this fundamental problem for knowledge bases and mappings
expressed in OWL 2 QL, the profile of OWL 2 based on the description logic
DL-Lite_R. More specifically, we consider the problem of computing universal
solutions, identified as one of the most desirable translations to be
materialized, and the problem of computing UCQ-representations, which optimally
capture in a target TBox the information that can be extracted from a source
TBox and a mapping by means of unions of conjunctive queries. For the former we
provide a novel automata-theoretic technique, and complexity results that range
from NP to EXPTIME, while for the latter we show NLOGSPACE-completeness.


title: Automorphic correction of the hyperbolic Kac-Moody algebra $E_{10}$

abstract:
  In this paper we study automorphic correction of the hyperbolic Kac-Moody
algebra $E_{10}$, using the Borcherds product for O(10,2) attached to a weakly
holomorphic modular form of weight -4 for $SL_2(\mathbb Z)$. We also clarify
some aspects of automorphic correction for Lorentzian Kac-Moody algebras and
give heuristic reasons for the expectation that every Lorentzian Kac-Moody
algebra has an automorphic correction.


title: QCD gauge symmetries through Faddeev-Jackiw symplectic method

abstract:
  The interactions between gluons are important in theories such as quantum
chromodynamics. Therefore, to rediscover new features of well known methods in
order to investigate the SU(3) gauge group can be a new way to deal with
Yang-Mills theories. In this work we analyzed YM theories through the well
known Faddeev-Jackiw formalism for constrained systems. Besides, we showed
precisely that having U(1) Maxwell electromagnetic theory as a starting point
we can construct SU(3)-like and SU(3) X SU(2) X U(1) non-Abelian theories.


title:
Estimates for Lorentz factors of gamma-ray bursts from early optical
  afterglow observations

abstract:
  The peak time of optical afterglow may be used as a proxy to constrain the
Lorentz factor Gamma of the gamma-ray burst (GRB) ejecta. We revisit this
method by including bursts with optical observations that started when the
afterglow flux was already decaying; these bursts can provide useful lower
limits on Gamma. Combining all analyzed bursts in our sample, we find that the
previously reported correlation between Gamma and the burst luminosity L_gamma
does not hold. However, the data clearly shows a lower bound Gamma_min which
increases with L_gamma. We suggest an explanation for this feature: explosions
with large jet luminosities and Gamma < Gamma_min suffer strong adiabatic
cooling before their radiation is released at the photosphere; they produce
weak bursts, barely detectable with present instruments. To test this
explanation we examine the effect of adiabatic cooling on the GRB location in
the L_gamma - Gamma plane using a Monte Carlo simulation of the GRB population.
Our results predict detectable on-axis "orphan" afterglows. We also derive
upper limits on the density of the ambient medium that decelerates the
explosion ejecta. We find that the density in many cases is smaller than
expected for stellar winds from normal Wolf-Rayet progenitors. The burst
progenitors may be peculiar massive stars with weaker winds or there might
exist a mechanism that reduces the stellar wind a few years before the
explosion.


title:
The standard lateral gene transfer model is statistically consistent for
  pectinate four-taxon trees

abstract:
  Evolutionary events such as incomplete lineage sorting and lateral gene
transfer constitute major problems for inferring species trees from gene trees,
as they can sometimes lead to gene trees which conflict with the underlying
species tree. One particularly simple and efficient way to infer species trees
from gene trees under such conditions is to combine three-taxon analyses for
several genes using a majority vote approach. For incomplete lineage sorting
this method is known to be statistically consistent, however, in the case of
lateral gene transfer it is known that a zone of inconsistency does exist for a
specific four-taxon tree topology. In this paper we analyze all remaining
four-taxon topologies and show that no other inconsistencies exist.


title: Radiative generation of the Higgs potential

abstract:
  We consider the minimal extension of the Standard Model with a generalized
B-L gauge symmetry U(1)_X for generating the Higgs potential radiatively.
Assuming that the full scalar potential vanishes at the vacuum instability
scale, we achieve the goal in terms of two free parameters, the X gauge
coupling and the right-handed neutrino Yukawa coupling. The X gauge symmetry is
broken spontaneously by the Coleman-Weinberg mechanism while the scale symmetry
breakdown induces electroweak symmetry breaking through the radiative
generation of appropriate scalar quartic couplings. We show that there is a
reasonable parameter space that is consistent with a correct electroweak
symmetry breaking and the observed Higgs mass.


title:
Moving from the Household to the Individual: Multidimensional Poverty
  Analysis

abstract:
  Current multidimensional measures of poverty continue to follow the
traditional income poverty approach of using household rather than the
individual as the unit of analysis. Household level measures are gender blind
since they ignore intra-household differences in resource allocation which have
been shown to differ along gender lines. In this study we use new data from the
Karnataka Household Asset Survey (KHAS) to construct an individual level
multidimensional poverty measure for Karnataka, India. Our results show that an
individual level measure can identify substantial gender differences in poverty
that are masked at the household level. We also find a large potential for
misclassification of poor individuals as non-poor when poverty is not assessed
at the individual level.


title: Frequency-Domain Group-based Shrinkage Estimators for UWB Systems

abstract:
  In this work, we propose low-complexity adaptive biased estimation
algorithms, called group-based shrinkage estimators (GSEs), for parameter
estimation and interference suppression scenarios with mechanisms to
automatically adjust the shrinkage factors. The proposed estimation algorithms
divide the target parameter vector into a number of groups and adaptively
calculate one shrinkage factor for each group. GSE schemes improve the
performance of the conventional least squares (LS) estimator in terms of the
mean-squared error (MSE), while requiring a very modest increase in complexity.
An MSE analysis is presented which indicates the lower bounds of the GSE
schemes with different group sizes. We prove that our proposed schemes
outperform the biased estimation with only one shrinkage factor and the best
performance of GSE can be obtained with the maximum number of groups. Then, we
consider an application of the proposed algorithms to single-carrier
frequency-domain equalization (SC-FDE) of direct-sequence ultra-wideband
(DS-UWB) systems, in which the structured channel estimation (SCE) algorithm
and the frequency domain receiver employ the GSE. The simulation results show
that the proposed algorithms significantly outperform the conventional unbiased
estimator in the analyzed scenarios.


title:
BCS model with asymmetric pair scattering: a non-Hermitian, exactly
  solvable Hamiltonian exhibiting generalised exclusion statistics

abstract:
  We demonstrate the occurrence of free quasi-particle excitations obeying
generalised exclusion statistics in a BCS model with asymmetric pair
scattering. The results are derived from an exact solution of the Hamiltonian,
which was obtained via the algebraic Bethe ansatz utilising the representation
theory of an underlying Yangian algebra. The free quasi-particle excitations
are associated to highest-weight states of the Yangian algebra, corresponding
to a class of analytic solutions of the Bethe ansatz equations.

categories: nlin.SI cond-mat.supr-con math-ph math.MP


title:
Reconstruction of the wave speed from transmission eigenvalues for the
  spherically-symmetric variable-speed wave equation

abstract:
  The unique reconstruction of a spherically-symmetric wave speed $v$ is
considered in a bounded spherical region of radius $b$ from the set of
corresponding transmission eigenvalues for which the corresponding
eigenfunctions are also spherically symmetric. If the integral of $1/v$ on the
interval $[0,b]$ is less than $b,$ assuming that there exists at least one $v$
corresponding to the data, $v$ is uniquely reconstructed from the data
consisting of such transmission eigenvalues and their "multiplicities," where
the multiplicity is defined as the multiplicity of the transmission eigenvalue
as a zero of a key quantity. When that integral is equal to $b,$ the unique
reconstruction is presented when the data set contains one additional piece of
information. Some similar results are presented for the unique reconstruction
of the potential from the transmission eigenvalues with multiplicities for a
related Schr\"odinger equation.


title:
Squeezing of a movable mirror via the dissipative optomechanical
  coupling

abstract:
  We investigate the squeezing for a movable mirror in the dissipative
optomechanics in which the oscillating mirror modulates both the resonance
frequency and the linewidth of the cavity mode. Via feeding a much weaker
broadband squeezed vacuum light accompanying the coherent driving laser field
into the cavity, the master equation for the cavity-mirror system is derived by
following the general reservoir theory based on the density operator in which
the reservoir variables are adiabatically eliminated by using the reduced
density operator for the system in the interaction picture. When the mirror is
weakly coupled to the cavity mode, we find that under the conditions of laser
cooling to the ground state, the driven cavity field can effectively perform as
a squeezed vacuum reservoir for the movable mirror via utilizing the completely
destructive interference of quantum noise, and thus the efficient transfer of
squeezing from the light to the movable mirror occurs, which is irrespective of
the ratio between the cavity damping rate and the mechanical frequency. When
the mirror is moderately coupled to the cavity mode, the photonic excitation
can preclude the completely destructive interference of quantum noise, and as a
consequence, the mirror deviates from the ideal squeezed state.


title:
A Unified Approach to Joint and Iterative Adaptive Interference
  Cancellation and Parameter Estimation for CDMA Systems in Multipath Channels

abstract:
  This paper proposes a unified approach to joint adaptive parameter estimation
and interference cancellation (IC) for direct sequence
code-division-multiple-access (DS-CDMA) systems in multipath channels. A
unified framework is presented in which the IC problem is formulated as an
optimization problem with extra degrees of freedom of an IC parameter vector
for each stage and user. We propose a joint optimization method for estimating
the IC parameter vector, the linear receiver filter front-end, and the channel
along with minimum mean squared error (MMSE) expressions for the estimators.
Based on the proposed joint optimization approach, we derive low-complexity
stochastic gradient (SG) algorithms for estimating the desired parameters.
Simulation results for the uplink of a synchronous DS-CDMA system show that the
proposed methods significantly outperform the best known IC receivers.


title: Bargaining for Revenue Shares on Tree Trading Networks

abstract:
  We study trade networks with a tree structure, where a seller with a single
indivisible good is connected to buyers, each with some value for the good, via
a unique path of intermediaries. Agents in the tree make multiplicative revenue
share offers to their parent nodes, who choose the best offer and offer part of
it to their parent, and so on; the winning path is determined by who finally
makes the highest offer to the seller. In this paper, we investigate how these
revenue shares might be set via a natural bargaining process between agents on
the tree, specifically, egalitarian bargaining between endpoints of each edge
in the tree. We investigate the fixed point of this system of bargaining
equations and prove various desirable for this solution concept, including (i)
existence, (ii) uniqueness, (iii) efficiency, (iv) membership in the core, (v)
strict monotonicity, (vi) polynomial-time computability to any given accuracy.
Finally, we present numerical evidence that asynchronous dynamics with randomly
ordered updates always converges to the fixed point, indicating that the fixed
point shares might arise from decentralized bargaining amongst agents on the
trade network.


title:
Towards a Formal Distributional Semantics: Simulating Logical Calculi
  with Tensors

abstract:
  The development of compositional distributional models of semantics
reconciling the empirical aspects of distributional semantics with the
compositional aspects of formal semantics is a popular topic in the
contemporary literature. This paper seeks to bring this reconciliation one step
further by showing how the mathematical constructs commonly used in
compositional distributional models, such as tensors and matrices, can be used
to simulate different aspects of predicate logic.
  This paper discusses how the canonical isomorphism between tensors and
multilinear maps can be exploited to simulate a full-blown quantifier-free
predicate calculus using tensors. It provides tensor interpretations of the set
of logical connectives required to model propositional calculi. It suggests a
variant of these tensor calculi capable of modelling quantifiers, using few
non-linear operations. It finally discusses the relation between these
variants, and how this relation should constitute the subject of future work.


title:
Advantages of the probability amplitude over the probability density in
  quantum mechanics

abstract:
  We discuss reasons why a probability amplitude, which becomes a probability
density after squaring, is considered as one of the most basic ingredients of
quantum mechanics. First, the Heisenberg/Schrodinger equation, an equation of
motion in quantum mechanics, describes a time evolution of the probability
amplitude rather than of a probability density. There may be reasons why
dynamics of a physical system are described by amplitude. In order to
investigate one role of the probability amplitude in quantum mechanics,
specialized codeword-transfer experiments are designed using classical
information theory. Within this context, quantum mechanics based on probability
amplitude provides the following: i) a minimum error of the codeword transfer;
ii) this error is independent of coding parameters; and iii) nontrivial and
nonlocal correlation can be realized. These are considered essential advantages
of the probability amplitude over the probability density.


title:
Electric-Field Ionization of Gallium Acceptors in Germanium Induced by
  Single-cycle Terahertz Pulses

abstract:
  The electric field ionization of gallium acceptors in germanium was studied
by using terahertz time-domain spectroscopy after single-cycle terahertz pulse
excitation. As the peak electric field of the excitation pulse increases, the
distinct absorptions due to acceptor transitions centered at 2.0 and 2.2 THz
decrease, and simultaneously, absorption emerges in the lower frequency region.
These behaviors clearly show that the terahertz pulse ionizes neutral
acceptors. The electric field dependence of the released hole density is well
reproduced by a model assuming direct field-assisted tunneling of acceptors.


title: On the symmetries of the modified Emden-type equation

abstract:
  For an autonomous system the symmetries of the Lagrangian are embedded in the
symmetries of the differential equation. Recently, it has been found that the
modified Emden-type equations follow from non-standard Lagrangian functions
which involve neither the kinetic energy term nor the potential function. By
working with one such Lagrangian we have calculated the Lagrangian symmetries
and explicitly demonstrated that, as in the case of standard Lagrangian
functions, the variational symmetries of the non-standard Lagrangian are also
included in the Lie symmetries of the differential equation.


title:
An Efficient MAC Protocol with Selective Grouping and Cooperative
  Sensing in Cognitive Radio Networks

abstract:
  In cognitive radio networks, spectrum sensing is a crucial technique to
discover spectrum opportunities for the Secondary Users (SUs). The quality of
spectrum sensing is evaluated by both sensing accuracy and sensing efficiency.
Here, sensing accuracy is represented by the false alarm probability and the
detection probability while sensing efficiency is represented by the sensing
overhead and network throughput. In this paper, we propose a group-based
cooperative Medium Access Control (MAC) protocol called GC-MAC, which addresses
the tradeoff between sensing accuracy and efficiency. In GC-MAC, the
cooperative SUs are grouped into several teams. During a sensing period, each
team senses a different channel while SUs in the same team perform the joint
detection on the targeted channel. The sensing process will not stop unless an
available channel is discovered. To reduce the sensing overhead, an
SU-selecting algorithm is presented to selectively choose the cooperative SUs
based on the channel dynamics and usage patterns. Then, an analytical model is
built to study the sensing accuracy-efficiency tradeoff under two types of
channel conditions: time-invariant channel and time-varying channel. An
optimization problem that maximizes achievable throughput is formulated to
optimize the important design parameters. Both saturation and non-saturation
situations are investigated with respect to throughput and sensing overhead.
Simulation results indicate that the proposed protocol is able to significantly
decrease sensing overhead and increase network throughput with guaranteed
sensing accuracy.


title: Likelihood-free methods for quantum parameter estimation

abstract:
  In this Letter, we strengthen and extend the connection between simulation
and estimation to exploit simulation routines that do not exactly compute the
probability of experimental data, known as the likelihood function. Rather, we
provide an explicit algorithm for estimating parameters of physical models
given access to a simulator which is only capable of producing sample outcomes.
Since our algorithm does not require that a simulator be able to efficiently
compute exact probabilities, it is able to exponentially outperform standard
algorithms based on exact computation. In this way, our algorithm opens the
door for the application of new insights and resources to the problem of
characterizing large quantum systems, which is exponentially intractable using
standard simulation resources.


title: Class numbers of ternary quadratic forms

abstract:
  G.L. Watson \cite{watson1, watson2} introduced a set of transformations,
called Watson transformations by most recent authors, in his study of the
arithmetic of integral quadratic forms. These transformations change an
integral quadratic form to another integral quadratic form with a smaller
discriminants, but preserve many arithmetic properties at the same time. In
this paper, we study the change of class numbers of positive definite ternary
integral quadratic formula along a sequence of Watson transformations, thus
providing a new and effective way to compute the class number of positive
definite ternary integral quadratic forms. Explicit class number formulae for
many genera of positive definite ternary integral quadratic forms are derived
as illustrations of our method.


title:
Contiguous relations and summation and transformation formulas for basic
  hypergeometric series

abstract:
  By using contiguous relations for basic hypergeometric series, we give simple
proofs of Bailey's $_4\phi_3$ summation, Carlitz's $_5\phi_4$ summation, Sears'
$_3\phi_2$ to $_5\phi_4$ transformation, Sears' ${}_4\phi_3$ transformations,
Chen's bibasic summation, Gasper's split poised $_{10}\phi_9$ transformation,
Chu's bibasic symmetric transformation. Along the same line, finite forms of
Sylvester's identity, Jacobi's triple product identity, and Kang's identity are
also obtained.


title: Some examples of minimal Cantor set for IFSs with overlap

abstract:
  We give some examples of IFSs with overlap on the interval such that the
semigroup action they give rise to has a minimal set homeomorphic to the Cantor
set.


title:
On the marginally trapped surfaces in Minkowski space-time with finite
  type Gauss map

abstract:
  In this paper, we work on the marginally trapped surfaces in the
4-dimensional Minkowski, de Sitter and anti-de Sitter space-times. We obtain
the complete classification of the marginally trapped surfaces in the Minkowski
space-time with pointwise 1-type Gauss map. Further, we give construction of
marginally trapped surfaces with 1-type Gauss map and a given boundary curve.
We also state some explicit examples. We also prove that a marginally trapped
surface in the de Sitter space-time $\mathbb S^4_1(1)$ or anti-de Sitter
space-time $\mathbb H^4_1(-1)$ has pointwise 1-type Gauss map if and only if
its mean curvature vector is parallel. Moreover, we obtain that there exists no
marginally trapped surface in $\mathbb S^4_1(1)$ or $\mathbb H^4_1(-1)$ with
harmonic Gauss map.


title: On the Equality of Ordinary and Symbolic Powers of Ideals

abstract:
  We consider the following question concerning the equality of ordinary and
symbolic powers of ideals. In a regular local ring, if the ordinary and
symbolic powers of a one-dimensional prime ideal are the same up to its height,
then are they the same for all powers? We provide supporting evidence of a
positive answer for classes of prime ideals defining monomial curves or rings
of low multiplicities.


title:
Reduced dynamics of two oscillators collectively coupled to a thermal
  bath

abstract:
  We study the reduced dynamics of a pair of non-degenerate oscillators coupled
collectively to a thermal bath. The model is related to the trilinear boson
model where the idler mode is promoted to a field. Due to nonlinear coupling,
the Markovian master equation for the pair of oscillators admits non-Gaussian
equilibrium states, where the modes distribute according to the Bose-Einstein
statistics. These states are metastable before the nonlinear coupling is taken
over by linear coupling between the individual oscillators and the field. The
Gibbs state for the individual modes lies in the subspace with infinite
occupation quantum number. We present the time evolution of a few states to
illustrate the behaviors of the system.


title:
Time-dependent complete-active-space self-consistent field method for
  multielectron dynamics in intense laser fields

abstract:
  The time-dependent complete-active-space self-consistent-field (TD-CASSCF)
method for the description of multielectron dynamics in intense laser fields is
presented, and a comprehensive description of the method is given. It
introduces the concept of frozen-core (to model tightly bound electrons with no
response to the field), dynamical-core (to model electrons tightly bound but
responding to the field), and active (fully correlated to describe ionizing
electrons) orbital subspaces, allowing compact yet accurate representation of
ionization dynamics in many-electron systems. The classification into the
subspaces can be done flexibly, according to simulated physical situations and
desired accuracy, and the multiconfiguration time-dependent Hartree-Fock
(MCTDHF) approach is included as a special case. To assess its performance, we
apply the TD-CASSCF method to the ionization dynamics of one-dimensional
lithium hydride (LiH) and LiH dimer models, and confirm that the present method
closely reproduces rigorous MCTDHF results if active orbital space is chosen
large enough to include appreciably ionizing electrons. The TD-CASSCF method
will open a way to the first-principle theoretical study of intense-field
induced ultrafast phenomena in realistic atoms and molecules.


title: Oscillation in microRNA Feedback Loop

abstract:
  The dynamic behaviors of microRNA and mRNA under external stress are studied
with biological experiments and mathematics models. In this study, we developed
a mathematic model to describe the biological phenomenon and for the first time
reported that, as responses to external stress, the expression levels of
microRNA and mRNA sustained oscillation. And the period of the oscillation is
much shorter than several reported transcriptional regulation negative feedback
loop.


title: Charge-Carrier Screening in Single-Layer Graphene

abstract:
  The effect of charge-carrier screening on the transport properties of a
neutral graphene sheet is studied by directly probing its electronic structure.
We find that the Fermi velocity, Dirac point velocity, and overall distortion
of the Dirac cone are renormalized due to the screening of the
electron-electron interaction in an unusual way. We also observe an increase of
the electron mean free path due to the screening of charged impurities. These
observations help us to understand the basis for the transport properties of
graphene, as well as the fundamental physics of these interesting
electron-electron interactions at the Dirac point crossing.