title:
On the Nature of the mHz X-Ray Quasi-periodic Oscillations from
  Ultraluminous X-Ray Source M82 X-1: Search for Timing-Spectral Correlations

abstract:
  Using all the archival XMM-Newton X-ray (3-10 keV) observations of the
ultraluminous X-ray source (ULX) M82 X-1 we searched for a correlation between
its variable mHz quasi-periodic oscillation (QPO) frequency and its hardness
ratio (5-10 keV/3-5 keV), an indicator of the energy spectral power-law index.
When stellar-mass black holes (StMBHs) exhibit Type-C low-frequency QPOs (~
0.2-15 Hz) the centroid frequency of the QPO is known to correlate with the
energy spectral index. The detection of such a correlation would strengthen the
identification of M82 X-1's mHz QPOs as Type-C and enable a more reliable mass
estimate by scaling its QPO frequencies to those of Type-C QPOs in StMBHs of
known mass. We resolved the count rates and the hardness ratios of M82 X-1 and
a nearby bright ULX (source 5/X42.3+59) through surface brightness modeling. We
detected QPOs in the frequency range of 36-210 mHz during which M82 X-1's
hardness ratio varied from 0.42-0.47. Our primary results are: (1) we do not
detect any correlation between the mHz QPO frequency and the hardness ratio (a
substitute for the energy spectral power-law index) and (2) similar to some
accreting X-ray binaries, we find that M82 X-1's mHz QPO frequency increases
with its X-ray count rate (Pearson's correlation coefficient = +0.97). The
apparent lack of a correlation between the QPO centroid frequency and the
hardness ratio poses a challenge to the earlier claims that the mHz QPOs of M82
X-1 are the analogs of the Type-C low-frequency QPOs of StMBHs. On the other
hand, it is possible that the observed relation between the hardness ratio and
the QPO frequency represents the saturated portion of the correlation seen in
Type-C QPOs of StMBHs -- in which case M82 X-1's mHz QPOs can still be
analogous to Type-C QPOs.


title:
Constraints on Hyperluminous QSO Lifetimes via Fluorescent Lya Emitters
  at Z~2.7

abstract:
  We present observations of a population of Lya emitters (LAEs) exhibiting
fluorescent emission via the reprocessing of ionizing radiation from nearby
hyperluminous QSOs. These LAEs are part of a survey at redshifts 2.5 < z < 2.9
combining narrow-band photometric selection and spectroscopic follow-up to
characterize the emission mechanisms, physical properties, and
three-dimensional locations of the emitters with respect to their nearby
hyperluminous QSOs. These data allow us to probe the radiation field, and thus
the radiative history, of the QSOs, and we determine that most of the 8 QSOs in
our sample have been active and of comparable luminosity for a time 1 Myr < t_Q
< 20 Myr. Furthermore, we find that the ionizing QSO emission must have an
opening angle theta ~ 30 deg or larger relative to the line of sight.


title:
Evidence for Quasi-periodic X-Ray Dips from an Ultraluminous X-Ray
  Source: Implications for the Binary Motion

abstract:
  We report results from long-term (approximately 1240 days) X-ray (0.3-8.0
keV) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the
Swift/X-Ray Telescope. Here we expand on earlier work by Strohmayer (2009) who
used only a part of the present data set. Our primary results are: (1) the
discovery of sharp, quasi-periodic, energy-independent dips in the X-ray
intensity that recur on average every 243 days, (2) the detection of an
energy-dependent (variability amplitude decreases with increasing energy),
quasi-sinusoidal X-ray modulation with a period of 112.6+-4 days the amplitude
of which weakens during the second half of the light curve and (3) spectral
evidence for an increase in photoelectric absorption during the last continuous
segment of the data. We interpret the X-ray modulations within the context of
binary motion in analogy to that seen in high-inclination accreting X-ray
binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an
orbital period of 243+-23 days, in contrast to the 115.5 day quasi-sinusoidal
period previously reported by Strohmayer (2009). We discuss the overall X-ray
modulation within the framework of accretion via Roche lobe overflow of the
donor star. In addition, if the X-ray modulation is caused by vertically
structured obscuring material in the accretion disk, this would imply a high
value for the inclination of the orbit. A comparison with estimates from
accreting X-ray binaries suggests an inclination > 70 degrees. We note that, in
principle, a precessing accretion disk could also produce the observed X-ray
modulations.


title:
Experimental entanglement activation from discord in a programmable
  quantum measurement

abstract:
  In quantum mechanics, observing is not a passive act. Consider a system of
two quantum particles A and B: if a measurement apparatus M is used to make an
observation on B, the overall state of the system AB will typically be altered.
When this happens no matter which local measurement is performed, the two
objects A and B are revealed to possess peculiar correlations known as quantum
discord. Here we demonstrate experimentally that the very act of local
observation gives rise to an activation protocol which converts discord into
distillable entanglement, a stronger and more useful form of quantum
correlations, between the apparatus M and the composite system AB. We adopt a
flexible two-photon setup to realize a three-qubit system (A,B,M) with
programmable degrees of initial correlations, measurement interaction, and
characterization processes. Our experiment demonstrates the fundamental
mechanism underpinning the ubiquitous act of observing the quantum world, and
establishes the potential of discord in entanglement generation.

categories: quant-ph cond-mat.stat-mech math-ph math.MP physics.optics


title:
Discovery of a 7 mHz X-Ray Quasi-periodic Oscillation from the most
  Massive Stellar-mass Black Hole IC 10 X-1

abstract:
  We report the discovery with XMM-Newton of an approximately 7 mHz X-ray
(0.3-10.0 keV) quasi-periodic oscillation (QPO) from the eclipsing,
high-inclination black hole binary IC 10 X-1. The QPO is significant at > 4.33
sigma confidence level and has a fractional amplitude (% rms) and a quality
factor, Q, of approximately 11 and 4, respectively. The overall X-ray (0.3-10.0
keV) power spectrum in the frequency range 0.0001 - 0.1 Hz can be described by
a power-law with an index of -2, and a QPO at 7 mHz. At frequencies > 0.02 Hz
there is no evidence for significant variability. The fractional amplitude
(rms) of the QPO is roughly energy-independent in the energy range of 0.3-1.5
keV. Above 1.5 keV the low signal to noise ratio of the data does not allow us
to detect the QPO. By directly comparing these properties with the wide range
of QPOs currently known from accreting black hole and neutron stars, we suggest
that the 7 mHz QPO of IC 10 X-1 may be linked to one of the following three
categories of QPOs: (1) the "heartbeat" mHz QPOs of the black hole sources GRS
1915+105 and IGR J17091-3624, or (2) the 0.6-2.4 Hz "dipper QPOs" of
high-inclination neutron star systems, or (3) the mHz QPOs of Cygnus X-3.


title:
Can the 62 day X-ray period of the Ultraluminous X-ray source M82 X-1 be
  due to a precessing accretion disk?

abstract:
  We have analyzed all archival RXTE/PCA monitoring observations of the
ultraluminous X-ray source (ULX) M82 X-1 in order to study the properties of
its 62 day X-ray period (Kaaret & Feng 2007). Based on its high coherence it
has been argued that the observed period is the orbital period of the binary.
Utilizing a much longer data set than in previous studies we find: (1) The
phase-resolved X-ray (3-15 keV) spectra -- modeled with a thermal accretion
disk and a power-law -- suggest that the accretion disk's contribution to the
total flux is strongly modulated with phase. (2) Suggestive evidence for a
sudden phase shift--of approximately 0.4 in phase (25 days)-- between the first
and the second halves of the light curve separated by roughly 1000 days. If
confirmed, the implied timescale to change the period is ~ 10 yrs, which is
exceptionally fast for an orbital phenomenon. These two independent pieces of
evidence are consistent with the periodicity being due to a precessing
accretion disk, similar to the super-orbital periods observed in systems like
Her X-1, LMC X-4, and SS433. However, the timing evidence for a change in the
period needs to be confirmed with additional observations. This should be
possible with further monitoring of M82 with instruments such as the Swift
X-ray telescope (XRT).


title: Conformal symmetry classes for pp-wave spacetimes

abstract:
  We determine conformal symmetry classes for the pp-wave spacetimes. This
refines the isometry classification scheme given by Sippel and Goenner (1986
{\it Gen. Rel. Grav.} {\bf 18} 1229). It is shown that every conformal Killing
vector for the null fluid type $N$ pp-wave spacetimes is a conformal Ricci
collineation. The maximum number of proper non-special conformal Killing
vectors in a type $N$ pp-wave spacetime is shown to be three, and we determine
the form of a particular set of type $N$ pp-wave spacetimes admitting such
conformal Killing vectors. We determine the conformal symmetries of each type
$N$ isometry class of Sippel and Goenner and present new isometry classes.


title: Studying the multi-wavelength signals from short GRBs

abstract:
  Since the first host galaxies and afterglows of short GRBs were identified,
they have remained very difficult to study: their multiwavelenth afterglows are
notoriously faint and host galaxy identification often relies upon minimalising
a chance alignment probability. Despite these observational challenges, there
is now a sufficiently large sample to constrain the properties of the wider
population and, in this review talk, I will summarise the current
multi-wavelength observations of short GRBs. Additionally, I will describe how
these observed data are able to both support and challenge the standard
theoretical models of the progenitors and central engines. Looking towards the
future, due to technological and theoretical advances, we are about to enter an
exciting era for the study of short GRBs. We will be able to search for
predicted counterparts in wide-field multi-wavelength transient searches and
have the tantalising prospect of finding the very first ``smoking gun'' signal
from the progenitor via the detection of gravitational waves.


title: Conformally reducible 1+3 spacetimes

abstract:
  Spacetimes which are conformally related to reducible 1+3 spacetimes are
considered. We classify these spacetimes according to the conformal algebra of
the underlying reducible spacetime, giving in each case canonical expressions
for the metric and conformal Killing vectors, and provide physically meaningful
examples.


title: Lecture Notes: Numerical Relativity in higher dimensional spacetimes

abstract:
  Black holes are among the most exciting phenomena predicted by General
Relativity and play a key role in fundamental physics. Many interesting
phenomena involve dynamical black hole configurations in the high curvature
regime of gravity. In these lecture notes I will summarise the main numerical
relativity techniques to explore highly dynamical phenomena, such as black hole
collisions, in generic $D$-dimensional spacetimes.


title:
The signature of the central engine in the weakest relativistic
  explosions: GRB100316D

abstract:
  We present late-time radio and X-ray observations of the nearby sub-energetic
Gamma-Ray Burst (GRB)100316D associated with supernova (SN) 2010bh. Our
broad-band analysis constrains the explosion properties of GRB100316D to be
intermediate between highly relativistic, collimated GRBs and the spherical,
ordinary hydrogen-stripped SNe. We find that ~10^49 erg is coupled to
mildly-relativistic (Gamma=1.5-2), quasi-spherical ejecta, expanding into a
medium previously shaped by the progenitor mass-loss with rate Mdot ~10^-5 Msun
yr^-1 (for wind velocity v_w = 1000 km s^-1). The kinetic energy profile of the
ejecta argues for the presence of a central engine and identifies GRB100316D as
one of the weakest central-engine driven explosions detected to date. Emission
from the central engine is responsible for an excess of soft X-ray radiation
which dominates over the standard afterglow at late times (t>10 days). We
connect this phenomenology with the birth of the most rapidly rotating
magnetars. Alternatively, accretion onto a newly formed black hole might
explain the excess of radiation. However, significant departure from the
standard fall-back scenario is required.


title: The Number Theoretic Hilbert Transform

abstract:
  This paper presents a general expression for a number-theoretic Hilbert
transform (NHT). The transformations preserve the circulant nature of the
discrete Hilbert transform (DHT) matrix together with alternating values in
each row being zero and non-zero. Specific examples for 4-point, 6-point, and
8-point NHT are provided. The NHT transformation can be used as a primitive to
create cryptographically useful scrambling transformations.


title:
Coherent Excitonic Coupling in an Asymmetric Double InGaAs Quantum Well
  Arises from Many-Body Effects

abstract:
  We study an asymmetric double InGaAs quantum well using optical
two-dimensional coherent spectroscopy. The collection of zero-quantum,
one-quantum, and two-quantum two-dimensional spectra provides a unique and
comprehensive picture of the double well coherent optical response. Coherent
and incoherent contributions to the coupling between the two quantum well
excitons are clearly separated. An excellent agreement with density matrix
calculations reveals that coherent interwell coupling originates from many-body
interactions.


title:
An analytic distribution function for a massless cored stellar system in
  a cuspy dark matter halo

abstract:
  We demonstrate the existence of distribution functions that can be used to
represent spherical massless cored stellar systems embedded in cuspy dark
matter halos with constant mildly tangential velocity anisotropy. In
particular, we derive analytically the functional form of the distribution
function for a Plummer stellar sphere in a Hernquist dark halo, for \beta_0 =
-0.5 and for different degrees of embedding. This particular example satisfies
the condition that the central logarithmic slope of the light profile \gamma_0
> 2 \beta_0. Our models have velocity dispersion profiles similar to those
observed in nearby dwarf spheroidal galaxies. Hence they can be used to
generate initial conditions for a variety of problems, including N-body
simulations that may represent dwarf galaxies in the Local Group.


title: The neutron polaron as a constraint on nuclear density functionals

abstract:
  We study the energy of an impurity (polaron) that interacts strongly in a sea
of fermions when the effective range of the impurity-fermion interaction
becomes important, thereby mapping the Fermi polaron of condensed matter
physics and ultracold atoms to strongly interacting neutrons. We present
Quantum Monte Carlo results for this neutron polaron, and compare these with
effective field theory calculations that also include contributions beyond the
effective range. We show that state-of-the-art nuclear density functionals vary
substantially and generally underestimate the neutron polaron energy. Our
results thus provide constraints for adjusting the time-odd components of
nuclear density functionals to better characterize polarized systems.


title: CLASH: A Census of Magnified Star-Forming Galaxies at z ~ 6-8

abstract:
  We utilize 16 band Hubble Space Telescope (HST) observations of 18 lensing
clusters obtained as part of the Cluster Lensing And Supernova survey with
Hubble (CLASH) Multi-Cycle Treasury program to search for $z\sim6-8$ galaxies.
We report the discovery of 204, 45, and 13 Lyman-break galaxy candidates at
$z\sim6$, $z\sim7$, and $z\sim8$, respectively, identified from purely
photometric redshift selections. This large sample, representing nearly an
order of magnitude increase in the number of magnified star-forming galaxies at
$z\sim 6-8$ presented to date, is unique in that we have observations in four
WFC3/UVIS UV, seven ACS/WFC optical, and all five WFC3/IR broadband filters,
which enable very accurate photometric redshift selections. We construct
detailed lensing models for 17 of the 18 clusters to estimate object
magnifications and to identify two new multiply lensed $z \gtrsim 6$
candidates. The median magnifications over the 17 clusters are 4, 4, and 5 for
the $z\sim6$, $z\sim7$, and $z\sim8$ samples, respectively, over an average
area of 4.5 arcmin$^2$ per cluster. We compare our observed number counts with
expectations based on convolving "blank" field UV luminosity functions through
our cluster lens models and find rough agreement down to $\sim27$ mag, where we
begin to suffer significant incompleteness. In all three redshift bins, we find
a higher number density at brighter observed magnitudes than the field
predictions, empirically demonstrating for the first time the enhanced
efficiency of lensing clusters over field surveys. Our number counts also are
in general agreement with the lensed expectations from the cluster models,
especially at $z\sim6$, where we have the best statistics.


title:
Exact asymptotically flat charged hairy black holes with a dilaton
  potential

abstract:
  We find broad classes of exact 4-dimensional asymptotically flat black hole
solutions in Einstein-Maxwell theories with a non-minimally coupled dilaton and
its non-trivial potential. We consider a few interesting limits, in particular,
a regular generalization of the dilatonic Reissner-Nordstr{\"o}m solution and,
also, smooth deformations of supersymmetric black holes. Further examples are
provided for more general dilaton potentials. We discuss the thermodynamical
properties and show that the first law is satisfied. In the non-extremal case
the entropy depends, as expected, on the asymptotic value of the dilaton. In
the extremal limit, the entropy is determined purely in terms of charges and is
independent of the asymptotic value of the dilaton. The attractor mechanism can
be used as a criterion for the existence of the regular solutions. Since there
is a `competition' between the effective potential and dilaton potential, we
also obtain regular extremal black hole solutions with just one U(1) gauge
field turned on.


title:
Free subalgebras of the skew polynomial rings k[x,y][t;\sigma] and
  k[x,x^{-1},y,y^{-1}][t;\sigma]

abstract:
  Let \sigma be an automorphism of a commutative k-algebra R. The skew
polynomial ring R[t;\sigma] is generated by R and an indeterminate t subject to
the relations ta=\sigma(a)t for all a in R. For certain R and appropriate
\sigma there are elements a and b in R such that the subalgebra of R[t;\sigma]
generated by at and bt is a free algebra. If \sigma is an automorphism of the
polynomial ring k[x,y], then the subalgebra of k[x,y][t;\sigma] generated by xt
and yt is free if and only if \sigma is not conjugate to an elementary
automorphism. If \sigma is an automorphism of k[x,x^{-1},y,y^{- 1}] of the form
\sigma(x)=x^ay^b and \sigma(y)=x^cy^d, then the subalgebra of k[x,x^{-1},y,y^{-
1}][t;\sigma] generated by xt and yt is free if the spectral radius of the 2x2
matrix {{a b} \\ {c d}} is >2; indeed, k[x,x^{-1},y,y^{- 1}][t;\sigma] contains
a free subalgebra if and only if the spectral radius of 2x2 matrix {{a b} \\ {c
d}} is >1.


title: Resurgent Transseries and the Holomorphic Anomaly

abstract:
  The gauge theoretic large N expansion yields an asymptotic series which
requires a nonperturbative completion in order to be well defined. Recently,
within the context of random matrix models, it was shown how to build resurgent
transseries solutions encoding the full nonperturbative information beyond the
't Hooft genus expansion. On the other hand, via large N duality, random matrix
models may be holographically described by B-model closed topological strings
in local Calabi-Yau geometries. This raises the question of constructing the
corresponding holographically dual resurgent transseries, tantamount to
nonperturbative topological string theory. This paper addresses this point by
showing how to construct resurgent transseries solutions to the holomorphic
anomaly equations. These solutions are built upon (generalized) multi-instanton
sectors, where the instanton actions are holomorphic. The asymptotic expansions
around the multi-instanton sectors have both holomorphic and anti-holomorphic
dependence, may allow for resonance, and their structure is completely fixed by
the holomorphic anomaly equations in terms of specific polynomials multiplied
by exponential factors and up to the holomorphic ambiguities -- which
generalizes the known perturbative structure to the full transseries. In
particular, the anti-holomorphic dependence has a somewhat universal character.
Furthermore, in the nonperturbative sectors, holomorphic ambiguities may be
fixed at conifold points. This construction shows the nonperturbative
integrability of the holomorphic anomaly equations, and sets the ground to
start addressing large-order analysis and resurgent nonperturbative completions
within closed topological string theory.


title:
An Easton-like Theorem for Zermelo-Fraenkel Set Theory Without Choice
  (Preliminary Report)

abstract:
  By Easton's theorem one can force the exponential function on regular
cardinals to take rather arbitrary cardinal values provided monotonicity and
Koenig's lemma are respected. In models without choice we employ a "surjective"
version of the exponential function. We then prove a choiceless Easton's
theorem: one can force the surjective exponential function on all infinite
cardinals to take arbitrary cardinal values, provided monotonicity and Cantor's
theorem are satisfied, irrespective of cofinalities.


title: Scattering Amplitudes

abstract:
  The purpose of this review is to bridge the gap between a standard course in
quantum field theory and recent fascinating developments in the studies of
on-shell scattering amplitudes. We build up the subject from basic quantum
field theory, starting with Feynman rules for simple processes in Yukawa theory
and QED. The material covered includes spinor helicity formalism, on-shell
recursion relations, superamplitudes and their symmetries, twistors and
momentum twistors, loops and integrands, Grassmannians, polytopes, and
amplitudes in perturbative supergravity as well as 3d Chern-Simons-matter
theories. Multiple examples and exercises are included.


title:
Measurements of Charge Transfer Efficiency in a Proton-irradiated Swept
  Charge Device

abstract:
  Charge Coupled Devices (CCDs) have been successfully used in several low
energy X-ray astronomical satellite over the past two decades. Their high
energy resolution and high spatial resolution make them an perfect tool for low
energy astronomy, such as formation of galaxy clusters and environment of black
holes. The Low Energy X-ray Telescope (LE) group is developing Swept Charge
Device (SCD) for the Hard X-ray Modulation Telescope (HXMT) satellite. SCD is a
special low energy X-ray CCD, which could be read out a thousand times faster
than traditional CCDs, simultaneously keeping excellent energy resolution. A
test method for measuring the charge transfer efficiency (CTE) of a prototype
SCD has been set up. Studies of the charge transfer inefficiency (CTI) have
been performed at a temperature range of operation, with a proton-irradiated
SCD.


title: Quadratic control of quantum processes

abstract:
  Within the framework of the Accardi-Fagnola-Quaegebeur (AFQ) representation
free calculus of \cite{b}, we consider the problem of controlling the size of a
quantum stochastic flow generated by a unitary stochastic evolution affected by
quantum noise. In the case when the evolution is driven by first order white
noise (which includes quantum Brownian motion) the control is shown to be given
in terms of the solution of an algebraic Riccati equation.
  This is done by first solving the problem of controlling (by minimizing an
associated quadratic performance criterion) a stochastic process whose
evolution is described by a stochastic differential equation of the type
considerd in \cite{b}. The solution is given as a feedback control law in terms
of the solution of a stochastic Riccati equation.


title:
A simple combinatorial interpretation of certain generalized Bell and
  Stirling numbers

abstract:
  In a series of papers, P. Blasiak et al. developed a wide-ranging
generalization of Bell numbers (and of Stirling numbers of the second kind)
that appears to be relevant to the so-called Boson normal ordering problem.
They provided a recurrence and, more recently, also offered a (fairly complex)
combinatorial interpretation of these numbers. We show that by restricting the
numbers somewhat (but still widely generalizing Bell and Stirling numbers), one
can supply a much more natural combinatorial interpretation. In fact, we offer
two different such interpretations, one in terms of graph colourings and
another one in terms of certain labelled Eulerian digraphs.


title: Optimal Hamiltonian of Fermion Flows

abstract:
  After providing a general formulation of Fermion flows within the context of
Hudson-Parthasarathy quantum stochastic calculus, we consider the problem of
determining the noise coefficients of the Hamiltonian associated with a Fermion
flow so as to minimize a naturally associated quadratic performance functional.
This extends to Fermion flows results of the authors previously obtained for
Boson flows .


title:
Speed of convergence for the realization of an effective subshift by a
  multidimensional SFT or Sofic

abstract:
  Realization of $d$-dimensional effective subshifts as projective sub-actions
of $d+d'$-dimensional sofic subshifts for $d'\geq 1$ is now well
know~\cite{Hochman-2009,Durand-Romashchenko-Shen-2010,Aubrun-Sablik-2010}. In
this paper we are interested in the speed of convergence of this realization.
That is to say given an effective subshift $\Sigma$ realized as projective
sub-action of a sofic $\T$, we study the function which on input an integer $k$
returns the smallest width of the strip which verify the local rules of $\T$
necessary to obtain exclusively the language of size $k$ of $\Sigma$ in the
central row of the strip. We study this topological conjugacy invariant for
effective subshifts in order to exhibit algorithmic properties of these
subshifts.


title: The Distribution of Dark Matter in the Milky Way's Disk

abstract:
  We present an analysis of the effects of dissipational baryonic physics on
the local dark matter (DM) distribution at the location of the Sun, with an
emphasis on the consequences for direct detection experiments. Our work is
based on a comparative analysis of two cosmological simulations of a Milky Way
halo: Eris, a full hydrodynamic simulation, and ErisDark, its DM-only
realization. We find that two distinct processes lead in Eris to a 30%
enhancement of DM in the disk plane at the location of the Sun: the accretion
and disruption of satellites resulting in a DM component with net angular
momentum and the contraction of baryons pulling DM into the disk plane without
forcing it to co-rotate. Owing to its particularly quiescent merger history for
dark halos of Milky Way mass, the co-rotating dark disk in Eris is less massive
than what has been suggested by previous work, contributing only 9% of the
local DM density. The speed distribution in Eris is broadened and shifted to
higher speeds compared to its DM-only twin simulation ErisDark. At high speeds
$f(v)$ falls more steeply in Eris than in ErisDark or the SHM, easing the
tension between recent results from the CDMS-II and XENON100 experiments. The
non-Maxwellian aspects of $f(v)$ are still present, but much less pronounced in
Eris than in DM-only runs. The weak dark disk increases the time-averaged
scattering rate by only a few percent at low recoil energies. On the high
velocity tail, however, the increase in typical speeds due to baryonic
contraction results in strongly enhanced mean scattering rates compared to
ErisDark, although they are still suppressed compared to the SHM. Similar
trends are seen regarding the amplitude of the annual modulation, while the
modulated fraction is increased compared to the SHM and decreased compared to
ErisDark.


title:
A general Multidimensional Monte Carlo Approach for Dynamic Hedging
  under stochastic volatility

abstract:
  In this work, we introduce a Monte Carlo method for the dynamic hedging of
general European-type contingent claims in a multidimensional Brownian
arbitrage-free market. Based on bounded variation martingale approximations for
Galtchouk-Kunita-Watanabe decompositions, we propose a feasible and
constructive methodology which allows us to compute pure hedging strategies
w.r.t arbitrary square-integrable claims in incomplete markets. In particular,
the methodology can be applied to quadratic hedging-type strategies for fully
path-dependent options with stochastic volatility and discontinuous payoffs. We
illustrate the method with numerical examples based on generalized
Follmer-Schweizer decompositions, locally-risk minimizing and mean-variance
hedging strategies for vanilla and path-dependent options written on local
volatility and stochastic volatility models.


title: Rotating lattice

abstract:
  We present the lattice QCD formulation in rotating frames. We start with the
continuum QCD action in rotating frames, and then discretize it on the lattice.
For the first test of the formulation, we calculate angular momentum in the
quenched Monte Carlo simulation, and confirm that the formulation works
successfully.


title:
Composition operators between two different bilateral grand Lebesgue
  spaces

abstract:
  In this paper we consider composition operator generated by nonsingular
measurable transformation between two different Grand Lebesgue Spaces (GLS); we
investigate the boundedness, compactness and essential norm of composition
operators.


title:
Measurement of form-factor independent observables in the decay $B^{0}
  \to K^{*0} \mu^+ \mu^-$

abstract:
  We present a measurement of form-factor independent angular observables in
the decay \mbox{$B^0\to K^{*}(892)^{0}\mu^+ \mu^-$}. The analysis is based on a
data sample corresponding to an integrated luminosity of 1.0fb$^{-1}$,
collected by the LHCb experiment in $pp$ collisions at a center-of-mass energy
of 7TeV. Four observables are measured in six bins of the dimuon invariant mass
squared, $q^2$, in the range $0.1<q^2<19.0$GeV$^{2}$/c$^{4}$. Agreement with
Standard Model predictions is found for 23 of the 24 measurements. A local
discrepancy, corresponding to $3.7$ Gaussian standard deviations, is observed
in one $q^2$ bin for one of the observables. Considering the 24 measurements as
independent, the probability to observe such a discrepancy, or larger, in one
is $0.5\%$.


title: Surface Plasmons and Nonlocality: a Simple Model

abstract:
  Surface plasmons on metals can concentrate light into sub-nanometric volumes
and on these near atomic length scales the electronic response at the metal
interface is smeared out over a Thomas-Fermi screening length. This nonlocality
is a barrier to a good understanding of atomic scale response to light and
complicates the practical matter of computing the fields. In this letter, we
present a local analogue model and show that spatial nonlocality can be
represented by replacing the nonlocal metal with a composite material,
comprising a thin dielectric layer on top of a local metal. This method not
only makes possible the quantitative analysis of nonlocal effects in complex
plasmonic phenomena with unprecedented simplicity and physical insight, but
also offers great practical advantages in their numerical treatment.


title: Quantum Speed Limit and optimal evolution time in a two-level system

abstract:
  Quantum mechanics establishes a fundamental bound for the minimum evolution
time between two states of a given system. Known as the quantum speed limit
(QSL), it is a useful tool in the context of quantum control, where the speed
of some control protocol is usually intended to be as large as possible. While
QSL expressions for time-independent hamiltonians have been well studied, the
time-dependent regime has remained somewhat unexplored, albeit being usually
the relevant problem to be compared with when studying systems controlled by
external fields. In this paper we explore the relation between optimal times
found in quantum control and the QSL bound, in the (relevant) time-dependent
regime, by discussing the ubiquitous two-level Landau-Zener type hamiltonian.


title: Harmonic maps between 3-dimensional hyperbolic spaces

abstract:
  We prove that a quasiconformal map of the 2-sphere admits a harmonic
quasi-isometric extension to the 3-dimensional hyperbolic space, thus
confirming the well known Schoen Conjecture in dimension 3.


title: Bounds on fifth forces at the sub-Angstrom length scale

abstract:
  Constraints on a possible fifth-force interaction between hadrons are derived
based on an analysis of results from laser precision frequency measurements of
antiprotonic helium atoms, both $\bar{p}\,^{4}$He$^{+}$ and
$\bar{p}\,^{3}$He$^{+}$ species, and from experiments on resonant formation
rates of $dd\mu^{+}$-ions in muon-catalyzed fusion processes. A comparison is
made between accurate experimental data and first-principles theoretical
descriptions of the exotic systems within a quantum electrodynamical framework.
The agreement between theory and experiment sets limits on a possible
additional hadron-hadron interaction written in the form of a Yukawa potential
$V_5(r)=\alpha_5 \exp(-r/\lambda)/r$, with $\lambda$ representing the
characteristic length scale associated with the mass of a hypothetical
force-carrying particle via $\lambda=\hbar/(m_5c)$. The laser spectroscopic
data of antiprotonic helium set a constraint of $\alpha_5/\alpha_{EM} <
10^{-8}$ for $\lambda < 1$ \AA, while the binding energy of the muonic
molecular deuterium ion delivers a constraint of $\alpha_5/\alpha_{EM} \sim
10^{-5}$ for $\lambda < 0.05$ \AA, where $\alpha_{EM}$ represents the strength
of the electromagnetic interaction or the fine structure constant.


title:
Constant Trace Anomaly as a Universal Condition for the Chemical
  Freeze-Out

abstract:
  Finding out universal conditions describing the freeze-out parameters was a
subject of various phenomenological studies. In the present work, we introduce
a new condition based on constant trace anomaly (or interaction measure)
calculated in the hadron resonance gas (HRG) model. Various extensions to the
{\it ideal} HRG which are conjectured to take into consideration different
types of interactions have been analysed. When comparing HRG thermodynamics to
that of lattice quantum chromodynamics, we conclude that the hard-core radii
are practically irrelevant, especially when HRG includes all resonances with
masses less than $2~$GeV. It is found that the constant trace anomaly (or
interaction measure) agrees well with most of previous conditions.


title: Functional Inequalities for Convolution Probability Measures

abstract:
  Let $\mu$ and $\nu$ be two probability measures on $\R^d$, where $\mu(\d x)=
\e^{-V(x)}\d x$ for some $V\in C^1(\R^d)$. Explicit sufficient conditions on
$V$ and $\nu$ are presented such that $\mu*\nu$ satisfies the log-Sobolev,
Poincar\'e and super Poincar\'e inequalities. In particular, the recent results
on the log-Sobolev inequality derived in \cite{Z} for convolutions of the
Gaussian measure and compactly supported probability measures are improved and
extended.


title:
The Effect of Student Learning Styles on the Learning Gains Achieved
  When Interactive Simulations Are Coupled with Real-Time Formative Assessment
  via Pen-Enabled Mobile Technology

abstract:
  This paper describes results from a project in an undergraduate engineering
physics course that coupled classroom use of interactive computer simulations
with the collection of real-time formative assessment using pen-enabled mobile
technology. Interactive simulations (free or textbook-based) are widely used
across the undergraduate science and engineering curriculia to help actively
engaged students increase their understanding of abstract concepts or phenomena
which are not directly or easily observable. However, there are indications in
the literature that we do not yet know the pedagogical best practices
associated with their use to maximize learning. This project couples student
use of interactive simulations with the gathering of real-time formative
assessment via pen-enabled mobile technology (in this case, Tablet PCs). The
research question addressed in this paper is: are learning gains achieved with
this coupled model greater for certain types of learners in undergraduate STEM
classrooms? To answer this, we correlate learning gains with various learning
styles, as identified using the Index of Learning Styles (ILS) developed by
Felder and Soloman. These insights will be useful for others who use
interactive computer simulations in their instruction and other adopters of
this pedagogical model; the insights may have broader implications about
modification of instruction to address various learning styles.


title: Oscillation and Mixing Among the Three Neutrino Flavors

abstract:
  With the educated, interested non-specialist as the target audience, we
overview what is known and not known about contemporary neutrino physics.
Theory tells us that neutrinos are the second-most common particle in the
Universe, behind only the quanta of radiation called photons. Almost a trillion
neutrinos per second enter each human eyeball, and yet we do not see them;
these neutrinos, in roughly equal numbers, are emanations from our Sun and
relics of the hot "big bang" era of the early Universe. Much of what we know
about neutrinos, and hope to learn in the future, is derived from a unique
feature of neutrinos -- "oscillation" among neutrino "flavor" types. An initial
neutrino flavor will in general oscillate into another flavor as the neutrino
propagates in space and time. Oscillations are a quantum mechanical phenomenon.
One of the wonders of neutrinos is that their quantum mechanics may be observed
over large distances, even astronomically large. We begin this article with
neutrino phenomenology in terms of masses and mixing angles, including the
matter-antimatter asymmetric "phase" that appears with three neutrino types.
Next we venture into neutrino oscillations. We conclude with a discussion of
model-building for the neutrino masses and mixings. Throughout this article,
attention is devoted to the 2012 result that the "small" neutrino mixing angle
is not so small, after all.


title:
Solar Flares with an Exponential Growth of the Emission Measure in the
  Impulsive Phase Derived from X-ray Observations

abstract:
  The light curves of solar flares in the impulsive phase are complex in
general, indicating that multiple physical processes are involved in. With the
GOES (Geostationary Operational Environmental Satellite) observations, we find
that there are a subset of flares, whose impulsive phases are dominated by a
period of exponential growth of the emission measure. The flares occurred from
January 1999 to December 2002 are analyzed, and the results from the
observations made with both GOES 8 and GEOS 10 satellites are compared to
estimate the instrumental uncertainties. Their mean temperatures during this
exponential growth phase have a normal distribution. Most flares within the
1\sigma\ range of this temperature distribution belong to the GOES class B or
C, with the peak fluxes at the GOES low-energy channel following a log-normal
distribution. The growth rate and duration of the exponential growth phase also
follow a lognormal distribution, in which the duration is distributed in the
range from half a minute to about half an hour. As expected, the growth time is
correlated with the decay time of the soft X-ray flux. We also find that the
growth rate of the emission measure is strongly anti-correlated with the
duration of the exponential growth phase, and the mean temperature increases
slightly with the increase of the growth rate. The implications of these
results on the study of energy release in solar flares are discussed in the
end.


title: Equilibration of quantum chaotic systems

abstract:
  Quantum ergordic theorem for a large class of quantum systems was proved by
von Neumann [Z. Phys. {\bf 57}, 30 (1929)] and again by Reimann [Phys. Rev.
Lett. {\bf 101}, 190403 (2008)] in a more practical and well-defined form.
However, it is not clear whether the theorem applies to quantum chaotic
systems. With the rigorous proof still elusive, we illustrate and verify this
theorem for quantum chaotic systems with examples. Our numerical results show
that a quantum chaotic system with an initial low-entropy state will
dynamically relax to a high-entropy state and reach equilibrium. The quantum
equilibrium state reached after dynamical relaxation bears a remarkable
resemblance to the classical micro-canonical ensemble. However, the
fluctuations around equilibrium are distinct: the quantum fluctuations are
exponential while the classical fluctuations are Gaussian.


title: Webs on surfaces, rings of invariants, and clusters

abstract:
  We construct and study cluster algebra structures in rings of invariants of
the special linear group action on collections of three-dimensional vectors,
covectors, and matrices. The construction uses Kuperberg's calculus of webs on
marked surfaces with boundary.


title:
Improved well-posedness for the quadratic derivative nonlinear wave
  equation in 2D

abstract:
  In this paper we consider the Cauchy problem for the nonlinear wave equation
(NLW) with quadratic derivative nonlinearities in two space dimensions.
Following Gr\"{u}nrock's result in 3D, we take the data in the Fourier-Lebesgue
spaces $\^{H}_s^r$, which coincide with the Sobolev spaces of the same
regularity for $r=2$, but scale like lower regularity Sobolev spaces for
$1<r<2$. We show local well-posedness (LWP) for the range of exponents
$s>1+\frac{3}{2r}$, $1<r\leq 2$. On one end this recovers the sharp result on
the Sobolev scale, $H^{\frac{7}{4}+}$, while on the other end establishes the
$\^{H}_{\frac{5}{2}}^{1+}$ result, which scales like the Sobolev
$H^{\frac{3}{2}+}$, thus, corresponding to a $\frac{1}{4}$ derivative
improvement on the Sobolev scale.


title:
Attenuation of superconductivity in manganite/cuprate heterostructures
  by epitaxially-induced CuO intergrowths

abstract:
  We examine the effect of CuO intergrowths on the superconductivity in
epitaxial La_{2/3}Ca_{1/3}MnO_3/YBa_2Cu_3O_{7-\delta} (LCMO/YBCO) thin-film
heterostructures. Scanning transmission electron microscopy on bilayer
LCMO/YBCO thin films revealed double CuO-chain intergrowths which form regions
with the 247 lattice structure in the YBCO layer. These nanoscale 247 regions
do not appear in x-ray diffraction, but can physically account for the reduced
critical temperature Tc of bilayer thin films relative to unilayer films with
the same YBCO thickness, at least down to ~25 nm. We attribute the CuO
intergrowths to the bilayer heteroepitaxial mismatch and the Tc reduction to
the generally lower Tc seen in bulk 247 samples. These epitaxially-induced CuO
intergrowths provide a microstructural mechanism for the attenuation of
superconductivity in LCMO/YBCO heterostructures.


title:
Balloons and Hoops and their Universal Finite Type Invariant, BF Theory,
  and an Ultimate Alexander Invariant

abstract:
  Balloons are two-dimensional spheres. Hoops are one dimensional loops.
Knotted Balloons and Hoops (KBH) in 4-space behave much like the first and
second homotopy groups of a topological space - hoops can be composed as in
\pi_1, balloons as in \pi_2, and hoops "act" on balloons as \pi_1 acts on
\pi_2. We observe that ordinary knots and tangles in 3-space map into KBH in
4-space and become amalgams of both balloons and hoops.
  We give an ansatz for a tree and wheel (that is, free-Lie and cyclic word)
-valued invariant \zeta of (ribbon) KBHs in terms of the said compositions and
action and we explain its relationship with finite type invariants. We
speculate that \zeta is a complete evaluation of the BF topological quantum
field theory in 4D. We show that a certain "reduction and repackaging" of \zeta
is an "ultimate Alexander invariant" that contains the Alexander polynomial
(multivariable, if you wish), has extremely good composition properties, is
evaluated in a topologically meaningful way, and is least-wasteful in a
computational sense. If you believe in categorification, that should be a
wonderful playground.


title: What is a Singularity in Geometrized Newtonian Gravitation?

abstract:
  I discuss singular spacetimes in the context of the geometrized formulation
of Newtonian gravitation. I argue first that geodesic incompleteness is a
natural criterion for when a model of geometrized Newtonian gravitation is
singular, and then I show that singularities in this sense arise naturally in
classical physics by stating and proving a classical version of the
Raychaudhuri-Komar singularity theorem.


title:
Small global solutions to the damped two-dimensional Boussinesq
  equations

abstract:
  The two-dimensional (2D) incompressible Euler equations have been thoroughly
investigated and the resolution of the global (in time) existence and
uniqueness issue is currently in a satisfactory status. In contrast, the global
regularity problem concerning the 2D inviscid Boussinesq equations remains
widely open. In an attempt to understand this problem, we examine the damped 2D
Boussinesq equations and study how damping affects the regularity of solutions.
Since the damping effect is insufficient in overcoming the difficulty due to
the "vortex stretching", we seek unique global small solutions and the efforts
have been mainly devoted to minimizing the smallness assumption. By positioning
the solutions in a suitable functional setting (more precisely the homogeneous
Besov space $\mathring{B}^1_{\infty,1}$), we are able to obtain a unique global
solution under a minimal smallness assumption.


title: A generalization of Kostant theorem to integral cohomology

abstract:
  In this paper, we find weight decomposition and rank of a weight in the
integral (co)homology of the positive system of a semi-simple Lie algebra over
$\Bbb C$ and prove that the (co)homology of the weight subcomplex over a field
of characteristic p is 0 if the rank of the weight is not divisible by p. This
generalizes Kostant theorem to the integral cohomology of the positive system.


title:
State Estimation over Sensor Networks with Correlated Wireless Fading
  Channels

abstract:
  Stochastic stability for centralized time-varying Kalman filtering over a
wireles ssensor network with correlated fading channels is studied. On their
route to the gateway, sensor packets, possibly aggregated with measurements
from several nodes, may be dropped because of fading links. To study this
situation, we introduce a network state process, which describes a finite set
of configurations of the radio environment. The network state characterizes the
channel gain distributions of the links, which are allowed to be correlated
between each other. Temporal correlations of channel gains are modeled by
allowing the network state process to form a (semi-)Markov chain. We establish
sufficient conditions that ensure the Kalman filter to be exponentially
bounded. In the one-sensor case, this new stability condition is shown to
include previous results obtained in the literature as special cases. The
results also hold when using power and bit-rate control policies, where the
transmission power and bit-rate of each node are nonlinear mapping of the
network state and channel gains.


title: Spin-5 Casimir Operator and Its Three-Point Functions with Two Scalars

abstract:
  By calculating the second-order pole in the operator product expansion (OPE)
between the spin-3 Casimir operator and the spin-4 Casimir operator known
previously, the spin-5 Casimir operator is obtained in the coset model based on
(A_{N-1}^{(1)} \oplus A_{N-1}^{(1)}, A_{N-1}^{(1)}) at level (k,1). This spin-5
Casimir operator consisted of the quintic, quartic (with one derivative) and
cubic (with two derivatives) WZW currents contracted with SU(N) invariant
tensors. The three-point functions with two scalars for all values of 't Hooft
coupling in the large N limit were obtained by analyzing the zero-mode
eigenvalue equations carefully. These three-point functions were dual to those
in AdS_3 higher spin gravity theory with matter. Furthermore, the exact
three-point functions that hold for any finite N and k are obtained. The zero
mode eigenvalue equations for the spin-5 current in CFT coincided with those of
the spin-5 field in asymptotic symmetry algebra of the higher spin theory on
the AdS_3. This paper also describes the structure constant appearing in the
spin-4 Casimir operator from the OPE between the spin-3 Casimir operator and
itself for N=4, 5 in the more general coset minimal model with two arbitrary
levels (k_1, k_2).


title:
Recovering the observed B/C ratio in a dynamic spiral-armed cosmic ray
  model

abstract:
  We develop a fully three dimensional numerical code describing the diffusion
of cosmic rays in the Milky Way. It includes the nuclear spallation chain up to
Oxygen, and allows the study of various cosmic ray properties, such as the CR
age, grammage traversed, and the ratio between secondary and primary particles.
This code enables us to explore a model in which a large fraction of the cosmic
ray acceleration takes place in the vicinity of galactic spiral arms and that
these spiral arms are dynamic. We show that the effect of having dynamic spiral
arms is to limit the age of cosmic rays at low energies. This is because at low
energies the time since the last spiral arm passage governs the Cosmic Ray (CR)
age, and not diffusion. Using the model, the observed spectral dependence of
the secondary to primary ratio is recovered without requiring any further
assumptions such as a galactic wind, re-acceleration or various assumptions on
the diffusivity. In particular, we obtain a secondary to primary ratio which
increases with energy below about 1 GeV.


title:
Fermi Contour Anisotropy of GaAs Electron-Flux Composite Fermions in
  Parallel Magnetic Fields

abstract:
  In high-quality two-dimensional electrons confined to GaAs quantum wells,
near Landau level filling factors $\nu=$ 1/2 and 1/4, we observe signatures of
the commensurability of the electron-flux composite fermion cyclotron orbits
with a unidirectional periodic density modulation. Focusing on the data near
$\nu=1/2$, we directly and quantitatively probe the shape of the composite
fermions' cyclotron orbit, and therefore their Fermi contour, as a function of
magnetic field ($B_{||}$) applied parallel to the sample plane. The composite
fermion Fermi contour becomes severely distorted with increasing $B_{||}$ and
appears to be elliptical, in sharp contrast to the electron Fermi contour which
splits as the system becomes bilayer-like at high $B_{||}$. We present a
simple, qualitative model to interpret our findings.


title:
On the transformations generated by the electromagnetic spin and orbital
  angular momentum operators

abstract:
  We present a study of the properties of the transversal "spin angular
momentum" and "orbital angular momentum" operators. We show that the "spin
angular momentum" operators are generators of spatial translations which depend
on helicity and frequency and that the "orbital angular momentum" operators
generate transformations which are a sequence of this kind of translations and
rotations. We give some examples of the use of these operators in light matter
interaction problems. Their relationship with the helicity operator allows to
involve the electromagnetic duality symmetry in the analysis. We also find that
simultaneous eigenstates of the three "spin" operators and parity define a type
of standing modes which has been recently singled out for the interaction of
light with chiral molecules. With respect to the relationship between "spin
angular momentum", polarization, and total angular momentum, we show that,
except for the case of a single plane wave, the total angular momentum of the
field is decoupled from its vectorial degrees of freedom even in the regime
where the paraxial approximation holds. Finally, we point out a relationship
between the three "spin" operators and the spatial part of the Pauli-Lubanski
four vector.


title: Optimizing scheme of probabilistic remote preparation state

abstract:
  We propose a new generalized remote state preparation protocol for using
non-maximally entangled state as a shared resource. Different from the previous
schemes, the parameters of measurement basis depend on not only the state of
preparation but also the state of quantum channel. The advantage of the present
protocols is that, by constructing a set of appropriate mutually orthogonal
measurement basis, the success probability is improved. It is worthwhile
noticing that the probability of success is determined by Alice's measurement.
If Alice's measurement is appropriate, the remote preparation can be
successfully realized with the maximal probability.


title: A "Boosted Fireball" Model for Structured Relativistic Jets

abstract:
  We present a model for relativistic jets which generates a particular angular
distribution of Lorentz factor and energy per solid angle. We consider a
fireball with specific internal energy E/M launched with bulk Lorentz factor
\gamma_B. This "boosted fireball" model is motivated by the phenomenology of
collapsar jets, but is applicable to a wide variety of relativistic flows. In
its center-of-momentum frame the fireball expands isotropically, converting its
internal energy into radially expanding flow with asymptotic Lorentz factor
\eta_0 ~ E/M. In the lab frame the flow is beamed, expanding with Lorentz
factor \Gamma = 2 \eta_0 \gamma_B in the direction of its initial bulk motion
and with characteristic opening angle \theta_0 ~ 1/\gamma_B. The flow is
jet-like with \Gamma \theta_0 ~ 2 \eta_0 such that jets with \Gamma >
1/\theta_0 are naturally produced. The choice \eta_0 ~ \gamma_B ~ 10 yields a
jet with \Gamma ~ 200 on-axis and angular structure characterized by opening
angle \theta_0 ~ 0.1 of relevance for cosmological GRBs, while \gamma_B >~ 1
may be relevant for low-luminosity GRBs. The model produces a family of
outflows, of relevance for different relativistic phenomena with structures
completely determined by \eta_0 and \gamma_B. We calculate the energy per unit
solid angle for the model and use it to compute light curves for comparison
with the widely used top-hat model. The jet break in the boosted fireball light
curve is greatly subdued when compared to the top-hat model because the edge of
the jet is smoother than for a top-hat. This may explain missing jet breaks in
afterglow light curves.


title:
Gauss-Manin connections for p-adic families of nearly overconvergent
  modular forms

abstract:
  We interpolate the Gauss-Manin connection in p-adic families of nearly
overconvergent modular forms. This gives a family of Maass-Shimura type
differential operators from the space of nearly overconvergent modular forms of
type r to the space of nearly overconvergent modular forms of type r + 1 with
p-adic weight shifted by 2. Our construction is purely geometric, using
Andreatta-Iovita-Stevens and Pilloni's geometric construction of eigencurves,
and should thus generalize to higher rank groups.


title:
Invitation to Ezhil: A Tamil Programming Language for Early
  Computer-Science Education

abstract:
  Ezhil is a Tamil programming language with support for imperative
programming, with mixed use of Tamil and English identifiers and
function-names. Ezhil programing system is targeted toward the K-12 (junior
high-school) level Tamil speaking students, as an early introduction to
thinking like a computer-scientist. We believe this 'numeracy' knowledge is
easily transferred over from a native language (Tamil) to the pervasive English
language programming systems, in Java, dot-Net, Ruby or Python. Ezhil is an
effort to improve access to computing in the 21st Century.


title:
Existence of attractors, homoclinic tangencies and singular
  hyperbolicity for flows

abstract:
  We prove that every $C^1$ generic three-dimensional flow has either
infinitely many sinks, or, infinitely many hyperbolic or singular-hyperbolic
attractors whose basins form a full Lebesgue measure set. We also prove in the
orientable case that the set of accumulation points of the sinks of a $C^1$
generic three-dimensional flow has no dominated splitting with respect to the
linear Poincar\'e flow. As a corollary we obtain that every three-dimensional
flow can be $C^1$ approximated by flows with homoclinic tangencies or by
singular-Axiom A flows.


title:
Synchrotron X-ray Spectroscopy Study on the Valence State in alpha- and
  beta-YbAlB4 at Low Temperatures and High Magnetic Fields

abstract:
  The valence state of Yb ions in beta-YbAlB4 and its polymorph alpha-YbAlB4
has been investigated by using X-ray absorption and emission spectroscopy in
SPring-8 at temperatures from 2 to 280 K. The observed Yb valence is 2.78 +-
0.01 in beta-YbAlB4 at 2 K by using the X-ray emission spectroscopy. The
valence is found to gradually increase with increasing temperature toward the
trivalent state, and the characteristic temperature of the valence fluctuation
is expected to be about 290 K. We also found a small increase in the Yb valence
(~0.002) by applying a magnetic field of 32 T at 40 K to beta-YbAlB4.


title: Clumps and Axisymmetric Features in Debris Discs

abstract:
  This paper studied the structures of debris discs, focusing on the conditions
that can form an axisymmetric-looking outer disc from systems with inner
clumps. The main conclusion was that as long as the dominated dust grains are
smaller than the blowout size, it is easy to form an axisymmetric-looking outer
debris disc, which is part of a quasi-steady state of the whole system. This
quasi-steady state is established through the balance between grain generations
and a continuous out-going grain flow. Assuming there is an event that starts
planetesimal collisions and the corresponding grain generations, this balance
can be approached in a few thousand years. This result suggested that a
quasi-steady-state picture could solve the possible mass budget problem of
Vega's outer debris disc.


title:
When do Local Operations and Classical Communication Suffice for
  Two-Qubit State Discrimination?

abstract:
  In this paper we consider the conditions under which a given ensemble of
two-qubit states can be optimally distinguished by local operations and
classical communication (LOCC). We begin by completing the \emph{perfect}
distinguishability problem of two-qubit ensembles - both for separable
operations and LOCC - by providing necessary and sufficient conditions for the
perfect discrimination of one pure and one mixed state. Then for the well-known
task of minimum error discrimination, it is shown that \textit{almost all}
two-qubit ensembles consisting of three pure states cannot be optimally
discriminated using LOCC. This is surprising considering that \textit{any} two
pure states can be distinguished optimally by LOCC. Special attention is given
to ensembles that lack entanglement, and we prove an easy sufficient condition
for when a set of three product states cannot be optimally distinguished by
LOCC, thus providing new examples of the phenomenon known as "non-locality
without entanglement". We next consider an example of $N$ parties who each
share the same state but who are ignorant of its identity. The state is drawn
from the rotationally invariant "trine ensemble", and we establish a tight
connection between the $N$-copy ensemble and Shor's "lifted" single-copy
ensemble. For any finite $N$, we prove that optimal identification of the
states cannot be achieved by LOCC; however as $N\to\infty$, LOCC can indeed
discriminate the states optimally. This is the first result of its kind.
Finally, we turn to the task of unambiguous discrimination and derive new lower
bounds on the LOCC inconclusive probability for symmetric states. When applied
to the double trine ensemble, this leads to a rather different
distinguishability character than when the minimum-error probability is
considered.


title:
Mean Field Linear-Quadratic-Gaussian (LQG) Games for Stochastic Integral
  Systems

abstract:
  In this paper we discuss a class of mean field linear-quadratic-Gaussian
(LQG) games for large population system which has never been addressed by
existing literature. The features of our works are sketched as follows. First
of all, our state is modeled by stochastic Volterra-type equation which leads
to some new study on stochastic "integral" system. This feature makes our setup
significantly different from the previous mean field games where the states
always follow some stochastic "differential" equations. Actually, our
stochastic integral system is rather general and can be viewed as natural
generalization of stochastic differential equations. In addition, it also
includes some types of stochastic delayed systems as its special cases. Second,
some new techniques are explored to tackle our mean-field LQG games due to the
special structure of integral system. For example, unlike the Riccati equation
in linear controlled differential system, some Fredholm-type equations are
introduced to characterize the consistency condition of our integral system via
the resolvent kernels. Third, based on the state aggregation technique, the
Nash certainty equivalence (NCE) equation is derived and the set of associated
decentralized controls are verified to satisfy the $\epsilon$-Nash equilibrium
property. To this end, some new estimates of stochastic Volterra equations are
developed which also have their own interests.


title:
I-V characteristics of short superconducting nanowires with different
  bias and shunt: a dynamic approach

abstract:
  We derived the I-V characteristics of short nanowire in the circuit with and
without resistive and inductive shunt. For that we used numerical calculations
in the framework of time-dependent Ginzburg-Landau equations with different
relaxation times for the amplitude and phase dynamics. We also derived
dependence of the I-V characteristics on flux in superconducting quantum
interference device (SQUID) made of such two weak links.


title: On the Estimation of Random Uncertainties of Star Formation Histories

abstract:
  The standard technique for measurement of random uncertainties of star
formation histories (SFHs) is the bootstrap Monte Carlo, in which the
color-magnitude diagram (CMD) is repeatedly resampled. The variation in SFHs
measured from the resampled CMDs is assumed to represent the random uncertainty
in the SFH measured from the original data. However, this technique
systematically and significantly underestimates the uncertainties for times in
which the measured star formation rate is low or zero, leading to overly (and
incorrectly) high confidence in that measurement. This study proposes an
alternative technique, the Markov Chain Monte Carlo (MCMC), which samples the
probability distribution of the parameters used in the original solution to
directly estimate confidence intervals. While the most commonly used MCMC
algorithms are incapable of adequately sampling a probability distribution that
can involve thousands of highly correlated dimensions, the Hybrid Monte Carlo
algorithm is shown to be extremely effective and efficient for this particular
task. Several implementation details, such as the handling of implicit priors
created by parameterization of the SFH, are discussed in detail.


title: Orbital order and Hund's rule frustration in Kondo lattices

abstract:
  We analyze a microscopic origin of the Kondo effect-assisted orbital order in
heavy-fermion materials. By studying the periodic two-orbital Anderson model
with two local electrons, we show that frustration of Hund's rule coupling due
to the Kondo effect leads to an incommensurate spiral orbital and magnetic
order, which exists only inside the Kondo screened (heavy-electron) phase. This
spiral state can be observed in neutron and resonant X-ray scattering
measurements in ${\rm U}$- and ${\rm Pr}$-based heavy-fermion compounds, and
realized in cold atomic gases, e.g. fermionic ${}^{173}{\rm Yb}$.


title:
Closing the Wedge with 300 fb^-1 and 3000 fb^-1 at the LHC: A Snowmass
  White Paper

abstract:
  The discovery of a Higgs boson at the LHC begins the era of directly
measuring the mechanism of electroweak symmetry breaking (EWSB). Searching for
extensions of the Standard Model (SM) EWSB sector at the LHC is of vital
importance. An important extension of the SM with an extended EWSB sector is
the Minimal Supersymmetric Standard Model (MSSM). In this white paper, we
extend current ATLAS and CMS bounds on direct searches for the heavy MSSM
neutral Higgs bosons to 300 fb^-1 and 3000 fb^-1 of data at the LHC. In
particular we focus on the \tau^+\tau^- channel and the pseudoscalar decay to
light Higgs boson and Z, with additional discussion on how to further close the
wedge.


title: Planar Superconducting Whispering Gallery Mode Resonators

abstract:
  We introduce a microwave circuit architecture for quantum signal processing
combining design principles borrowed from high-Q 3D resonators in the quantum
regime and from planar structures fabricated with standard lithography. The
resulting '2.5D' whispering-gallery mode resonators store 98% of their energy
in vacuum. We have measured internal quality factors above 3 million at the
single photon level and have used the device as a materials characterization
platform to place an upper bound on the surface resistance of thin film
aluminum of less than 250nOhms.


title:
Adaptive Controller Placement for Wireless Sensor-Actuator Networks with
  Erasure Channels

abstract:
  Wireless sensor-actuator networks offer flexibility for control design. One
novel element which may arise in networks with multiple nodes is that the role
of some nodes does not need to be fixed. In particular, there is no need to
pre-allocate which nodes assume controller functions and which ones merely
relay data. We present a flexible architecture for networked control using
multiple nodes connected in series over analog erasure channels without
acknowledgments. The control architecture proposed adapts to changes in network
conditions, by allowing the role played by individual nodes to depend upon
transmission outcomes. We adopt stochastic models for transmission outcomes and
characterize the distribution of controller location and the covariance of
system states. Simulation results illustrate that the proposed architecture has
the potential to give better performance than limiting control calculations to
be carried out at a fixed node.


title:
Power Control and Coding Formulation for State Estimation with Wireless
  Sensors

abstract:
  Technological advances have made wireless sensors cheap and reliable enough
to be brought into industrial use. A major challenge arises from the fact that
wireless channels introduce random packet dropouts. Power control and coding
are key enabling technologies in wireless communications to ensure efficient
communications. In the present work, we examine the role of power control and
coding for Kalman filtering over wireless correlated channels. Two estimation
architectures are considered: In the first, the sensors send their measurements
directly to a single gateway. In the second scheme, wireless relay nodes
provide additional links. The gateway decides on the coding scheme and the
transmitter power levels of the wireless nodes. The decision process is carried
out on-line and adapts to varying channel conditions in order to improve the
trade-off between state estimation accuracy and energy expenditure. In
combination with predictive power control, we investigate the use of
multiple-description coding, zero-error coding and network coding and provide
sufficient conditions for the expectation of the estimation error covariance
matrix to be bounded. Numerical results suggest that the proposed method may
lead to energy savings of around 50 %, when compared to an alternative scheme,
wherein transmission power levels and bit-rates are governed by simple logic.
In particular, zero-error coding is preferable at time instances with high
channel gains, whereas multiple-description coding is superior for time
instances with low gains. When channels between the sensors and the gateway are
in deep fades, network coding improves estimation accuracy significantly
without sacrificing energy efficiency.


title:
Online Decision Making in Crowdsourcing Markets: Theoretical Challenges
  (Position Paper)

abstract:
  Over the past decade, crowdsourcing has emerged as a cheap and efficient
method of obtaining solutions to simple tasks that are difficult for computers
to solve but possible for humans. The popularity and promise of crowdsourcing
markets has led to both empirical and theoretical research on the design of
algorithms to optimize various aspects of these markets, such as the pricing
and assignment of tasks. Much of the existing theoretical work on crowdsourcing
markets has focused on problems that fall into the broad category of online
decision making; task requesters or the crowdsourcing platform itself make
repeated decisions about prices to set, workers to filter out, problems to
assign to specific workers, or other things. Often these decisions are complex,
requiring algorithms that learn about the distribution of available tasks or
workers over time and take into account the strategic (or sometimes irrational)
behavior of workers.
  As human computation grows into its own field, the time is ripe to address
these challenges in a principled way. However, it appears very difficult to
capture all pertinent aspects of crowdsourcing markets in a single coherent
model. In this paper, we reflect on the modeling issues that inhibit
theoretical research on online decision making for crowdsourcing, and identify
some steps forward. This paper grew out of the authors' own frustration with
these issues, and we hope it will encourage the community to attempt to
understand, debate, and ultimately address them.
  The authors welcome feedback for future revisions of this paper.


title: Sequence-based Anytime Control

abstract:
  We present two related anytime algorithms for control of nonlinear systems
when the processing resources available are time-varying. The basic idea is to
calculate tentative control input sequences for as many time steps into the
future as allowed by the available processing resources at every time step.
This serves to compensate for the time steps when the processor is not
available to perform any control calculations. Using a stochastic Lyapunov
function based approach, we analyze the stability of the resulting closed loop
system for the cases when the processor availability can be modeled as an
independent and identically distributed sequence and via an underlying Markov
chain. Numerical simulations indicate that the increase in performance due to
the proposed algorithms can be significant.


title: Updated Analysis of the Mass of the H Dibaryon from Lattice QCD

abstract:
  Recent lattice QCD calculations from the HAL and NPLQCD Collaborations have
reported evidence for the existence of a bound state with strangeness -2 and
baryon number 2 at quark masses somewhat higher than the physical values. A
controlled chiral extrapolation of these lattice results to the physical point
suggested that the state, identified with the famed H dibaryon, is most likely
slightly unbound (by 13 $\pm$ 14 MeV) with respect to the $\Lambda--\Lambda$
threshold. We report the results of an updated analysis which finds the H
unbound by 26 $\pm$ 11 MeV. Apart from the insight it would give us into how
QCD is realized in Nature, the H is of great interest because of its potential
implications for the equation of state of dense matter and studies of neutron
stars. It may also explain the enhancement above the $\Lambda--\Lambda$
threshold already reported experimentally. It is clearly of great importance
that the latter be pursued in experiments at the new J-PARC facility.


title:
Fractality of profit landscapes and validation of time series models for
  stock prices

abstract:
  We apply a simple trading strategy for various time series of real and
artificial stock prices to understand the origin of fractality observed in the
resulting profit landscapes. The strategy contains only two parameters $p$ and
$q$, and the sell (buy) decision is made when the log return is larger
(smaller) than $p$ ($-q$). We discretize the unit square $(p, q) \in [0, 1]
\times [0, 1]$ into the $N \times N$ square grid and the profit $\Pi (p, q)$ is
calculated at the center of each cell. We confirm the previous finding that
local maxima in profit landscapes are scattered in a fractal-like fashion: The
number M of local maxima follows the power-law form $M \sim N^{a}$, but the
scaling exponent $a$ is found to differ for different time series. From
comparisons of real and artificial stock prices, we find that the fat-tailed
return distribution is closely related to the exponent $a \approx 1.6$ observed
for real stock markets. We suggest that the fractality of profit landscape
characterized by $a \approx 1.6$ can be a useful measure to validate time
series model for stock prices.


title:
Classical to quantum transition of near-field heat transfer between two
  nanoparticles

abstract:
  Heat transfer between two silica clusters is investigated by using the
non-equilibrium Green's function method. In the gap range between 4 {\AA} and
three times the cluster size, the thermal conductance decreases as predicted by
the surface charge-charge interaction. Above five times the cluster size, the
volume dipole-dipole interaction predominates. Finally, when the distance
becomes smaller than 4 {\AA}, a quantum interaction where the electrons of both
clusters are shared takes place. This quantum interaction leads to the dramatic
increase of the thermal coupling between neighbor clusters due to strong
interactions. This study finally provides a description of the transition
between radiation and heat conduction in gaps smaller than a few nanometers.


title:
Interface control of the magnetic chirality in TaN|CoFeB|MgO
  heterosctructures

abstract:
  Recent advances in the understanding of spin orbital effects in ultrathin
magnetic heterostructures have opened new paradigms to control magnetic moments
electrically. The Dzyaloshinskii-Moriya interaction (DMI) is said to play a key
role in forming a Neel-type domain wall that can be driven by the spin Hall
torque, a torque resulting from the spin current generated in a neighboring
non-magnetic layer via the spin Hall effect. Here we show that the sign of the
DMI, which determines the direction to which a domain wall moves with current,
can be changed by modifying the adjacent non-magnetic layer. We find that the
sense of rotation of a domain wall spiral is reversed when the Ta underlayer is
doped with nitrogen in Ta|CoFeB|MgO heterostructures. The spin Hall angle of
the Ta and nitrogen doped Ta underlayers carry the same sign, suggesting that
the sign of the DMI is defined at the interface. Depending on the sense of
rotation, spin transfer torque and spin Hall torque can either compete or
assist each other, thus influencing the efficiency of moving domain walls with
current.


title: Weakly Circle-Preserving Maps in Inversive Geometry

abstract:
  Let S^n be the standard n-sphere embedded in R^{n+1}. A mapping T: S^n \to
S^n, not assumed continuous or even measurable, nor injective, is called weakly
circle-preserving if the image of any circle under T is contained in some
circle in the range space S^n. The main result of this paper shows that any
weakly circle-preserving map satisfying a very mild condition on its range
T(S^n) must be a Mobius transformation.


title:
Elliptic flow splitting as a probe of the QCD phase structure at finite
  baryon chemical potential

abstract:
  Using a partonic transport model based on the 3-flavor Nambu-Jona-Lasinio
model and a relativistic hadronic transport model to describe, respectively,
the evolution of the initial partonic and the final hadronic phase of heavy-ion
collisions at energies carried out in the Beam-Energy Scan program of the
Relativistic Heavy Ion Collider, we have studied the effects of both the
partonic and hadronic mean-field potentials on the elliptic flow of particles
relative to that of their antiparticles. We find that to reproduce the measured
relative elliptic flow differences between nucleons and antinucleons as well as
between kaons and antikaons requires a vector coupling constant as large as 0.5
to 1.1 times the scalar coupling constant in the Nambu-Jona-Lasinio model.
Implications of our results in understanding the QCD phase structure at finite
baryon chemical potential are discussed.


title: Q criterion for disc stability modified by external tidal field

abstract:
  The standard Q criterion (with Q > 1) describes the local stability of a disc
supported by rotation and random motion. Most astrophysical discs, however, are
under the influence of an external gravitational field which can affect their
stability. A typical example is a galactic disc embedded in a dark matter halo.
Here we do a linear perturbation analysis for a disc in an external field, and
obtain a generalized dispersion relation and a modified stability criterion. An
external field has two effects on the disc dynamics: first, it contributes to
the unperturbed rotational field, and second, it adds a tidal field term in the
stability parameter. A typical disruptive tidal field results in a higher
modified Q value and hence leads to a more stable disc. We apply these results
to the Milky Way, and to a low surface brightness galaxy UGC 7321. We find that
in each case the stellar disc by itself is barely stable and it is the dark
matter halo that stabilizes the disc against local, axisymmetric gravitational
instabilities. This result has been largely missed so far because in practice
the value for Q for a galactic disc is obtained in a hybrid fashion using the
observed rotational field that is set by both the disc and the halo, and hence
is higher than for a pure disc.


title:
Thermal and Non-thermal X-Rays from the Galactic Supernova Remnant
  G348.5+0.1

abstract:
  We report on Suzaku results of the two distinct regions in the Galactic
supernova remnant G348.5+0.1: extended thermal X-rays ("soft diffuse") at the
northeast region and non-thermal X-rays (CXOU J171419.8-383023) at the
northwest region. The X-ray spectrum of the soft diffuse is fitted with neither
an ionization equilibrium nor a non-equilibrium (ionizing) plasma model,
leaving saw-teeth residuals in the 1.5-3 keV energy band. The residual
structures can be produced when free electrons are recombined to the K-shells
of highly ionized Mg and Si ions. In fact, the X-ray spectrum is nicely fitted
with a recombination-dominant plasma model. We propose a scenario that the
plasma in nearly full ionized state at high temperature quickly changed to a
recombining phase due to selective cooling of electrons to a lower temperature
of ~0.5 keV. The spectrum of CXOU J171419.8-383023 is well explained by a
simple power-law model with a photon index of 1.9, nearly equal to the typical
value of pulsar wind nebulae. Since the distance is estimated to be the same as
that of the soft diffuse, we infer that both the soft diffuse and CXOU
J171419.8-383023 are associated with the same object, SNR G348.5+0.1.


title: Diagram automorphisms and Rank-Level duality

abstract:
  We study the effect of diagram automorphisms on rank-level duality. We use it
to prove new symplectic rank-level dualities on genus zero smooth curves with
marked points and chosen coordinates. We also show that rank-level dualities
for the pair sl(r), sl(s) in genus 0 arising from representation theory can
also be obtained from the parabolic strange duality proved by R. Oudompheng.


title:
Effective String Theory Inspired Potential and Meson Masses in Higher
  Dimension

abstract:
  Nambu-Goto action in classical bosonic string model for hadrons predicts
quark-antiquark potential to be\cite{Nambu-Goto} $V(r)=-\frac{\gamma}{r}+\sigma
r +\mu_0$. In this report we present studies of masses of heavy flavour mesons
in higher dimension with our recently developed wave functions obtained
following string inspired potential. We report the dimensional dependence of
the masses of mesons. Our results suggest that as the meson mass increases with
the number of extra spatial dimension, it will attain the Planck scale ($ \sim
10^{19}GeV$) asymptotically at an astronomically large spatial dimension (we
call it Planck dimension) $D_{Planck} \sim 10^{11}$, which sets the limit of
applicability of Schrodinger equation in large dimension.


title: Compressed Modes for Variational Problems in Mathematics and Physics

abstract:
  This paper describes a general formalism for obtaining localized solutions to
a class of problems in mathematical physics, which can be recast as variational
optimization problems. This class includes the important cases of
Schr\"odinger's equation in quantum mechanics and electromagnetic equations for
light propagation in photonic crystals. These ideas can also be applied to
develop a spatially localized basis that spans the eigenspace of a differential
operator, for instance, the Laplace operator, generalizing the concept of plane
waves to an orthogonal real-space basis with multi-resolution capabilities.


title:
An Improved analysis of Isgur-Wise Function for Heavy Light Mesons in
  $D$ dimensional Potential Model

abstract:
  This letter reports some improvement of the formalism and analysis of our
very recent work \cite{SR1} on the studies of Isgur-Wise function for
heavy-light mesons following higher dimensional string inspired potential
model.


title: Evidence for a bottom baryon resonance Lambda_b* in CDF data

abstract:
  Using data from proton-antiproton collisions at Ecms=1.96 TeV recorded by the
CDF II detector at the Fermilab Tevatron, evidence for the excited resonance
state Lambda_b* is presented in its Lambda_b0 pi+ pi- decay, followed by the
Lambda_b0 -->Lambda_c+ (-->proton K- pi+) pi- decays. The analysis is based on
a data sample corresponding to an integrated luminosity of 9.6/fb collected by
an online event selection based on charged-particle tracks displaced from the
proton-antiproton interaction point. The significance of the observed signal is
3.5 Gaussian sigmas. The mass of the observed state is found to be 5919.22 +-
0.76 MeV in agreement with similar findings in proton-proton collision
experiments.


title: The Deterministic Capacity of Relay Networks with Relay Private Messages

abstract:
  We study the capacity region of a deterministic 4-node network, where 3 nodes
can only communicate via the fourth one. However, the fourth node is not merely
a relay since it can exchange private messages with all other nodes. This
situation resembles the case where a base station relays messages between users
and delivers messages between the backbone system and the users. We assume an
asymmetric scenario where the channel between any two nodes is not reciprocal.
First, an upper bound on the capacity region is obtained based on the notion of
single sided genie. Subsequently, we construct an achievable scheme that
achieves this upper bound using a superposition of broadcasting node 4 messages
and an achievable "detour" scheme for a reduced 3-user relay network.


title:
Spatial mixing and approximation algorithms for graphs with bounded
  connective constant

abstract:
  The hard core model in statistical physics is a probability distribution on
independent sets in a graph in which the weight of any independent set I is
proportional to lambda^(|I|), where lambda > 0 is the vertex activity. We show
that there is an intimate connection between the connective constant of a graph
and the phenomenon of strong spatial mixing (decay of correlations) for the
hard core model; specifically, we prove that the hard core model with vertex
activity lambda < lambda_c(Delta + 1) exhibits strong spatial mixing on any
graph of connective constant Delta, irrespective of its maximum degree, and
hence derive an FPTAS for the partition function of the hard core model on such
graphs. Here lambda_c(d) := d^d/(d-1)^(d+1) is the critical activity for the
uniqueness of the Gibbs measure of the hard core model on the infinite d-ary
tree. As an application, we show that the partition function can be efficiently
approximated with high probability on graphs drawn from the random graph model
G(n,d/n) for all lambda < e/d, even though the maximum degree of such graphs is
unbounded with high probability.
  We also improve upon Weitz's bounds for strong spatial mixing on bounded
degree graphs (Weitz, 2006) by providing a computationally simple method which
uses known estimates of the connective constant of a lattice to obtain bounds
on the vertex activities lambda for which the hard core model on the lattice
exhibits strong spatial mixing. Using this framework, we improve upon these
bounds for several lattices including the Cartesian lattice in dimensions 3 and
higher.
  Our techniques also allow us to relate the threshold for the uniqueness of
the Gibbs measure on a general tree to its branching factor (Lyons, 1989).


title:
Linear Network Coding on Multi-Mesh of Trees (MMT) using All to All
  Broadcast (AAB)

abstract:
  We introduce linear network coding on parallel architecture for multi-source
finite acyclic network. In this problem, different messages in diverse time
periods are broadcast and every nonsource node in the network decodes and
encodes the message based on further communication.We wish to minimize the
communication steps and time complexity involved in transfer of data from
node-to-node during parallel communication.We have used Multi-Mesh of Trees
(MMT) topology for implementing network coding. To envisage our result, we use
all-to-all broadcast as communication algorithm.


title:
Dynamics of a two-level system under the simultaneous influence of a
  spin bath and a boson bath

abstract:
  We study dynamics of a two-level system coupled simultaneously to a pair of
dissimilar reservoirs, namely, a spin bath and a boson bath, which are
connected via finite interbath coupling. It is found that the steady-state
energy transfer in the two-level system increases with its coupling to the spin
bath while optimal transfer occurs at intermediate coupling in the transient
process. If the two-level system is strongly coupled to the spin bath, the
population transfer is unidirectional barring minor population oscillations of
minute amplitudes. If the spin bath is viewed as an atomic ensemble, robust
generation of macroscopic superposition states exists against parameter
variations of the two-level system and the boson bath.

categories: quant-ph cond-mat.other physics.bio-ph physics.chem-ph


title:
Explicit formula of energy-conserving Fokker-Planck type collision term
  for single species point vortex systems with weak mean flow

abstract:
  This paper derives a kinetic equation for a two-dimensional single species
point vortex system. We consider a situation (different from the ones
considered previously) of weak mean flow where the time scale of the
macroscopic motion is longer than the decorrelation time so that the trajectory
of the point vortices can be approximated by a straight line on the
decorrelation time scale. This may be the case when the number $N$ of point
vortices is not too large. Using a kinetic theory based on the Klimontovich
formalism, we derive a collision term consisting of a diffusion term and a
drift term, whose structure is similar to the Fokker-Planck equation. The
collision term exhibits several important properties: (a) it includes a
nonlocal effect; (b) it conserves the mean field energy; (c) it satisfies the H
theorem; (d) its effect vanishes in each local equilibrium region with the same
temperature. When the system reaches a global equilibrium state, the collision
term completely converges to zero all over the system.


title:
Limiting spectral distribution of renormalized separable sample
  covariance matrices when $p/n\to 0$

abstract:
  We are concerned with the behavior of the eigenvalues of renormalized sample
covariance matrices of the form
C_n=\sqrt{\frac{n}{p}}\left(\frac{1}{n}A_{p}^{1/2}X_{n}B_{n}X_{n}^{*}A_{p}^{1/2}-\frac{1}{n}\tr(B_{n})A_{p}\right)
as $p,n\to \infty$ and $p/n\to 0$, where $X_{n}$ is a $p\times n$ matrix with
i.i.d. real or complex valued entries $X_{ij}$ satisfying $E(X_{ij})=0$,
$E|X_{ij}|^2=1$ and having finite fourth moment. $A_{p}^{1/2}$ is a square-root
of the nonnegative definite Hermitian matrix $A_{p}$, and $B_{n}$ is an
$n\times n$ nonnegative definite Hermitian matrix. We show that the empirical
spectral distribution (ESD) of $C_n$ converges a.s. to a nonrandom limiting
distribution under some assumptions. The probability density function of the
LSD of $C_{n}$ is derived and it is shown that it depends on the LSD of $A_{p}$
and the limiting value of $n^{-1}\tr(B_{n}^2)$. We propose a computational
algorithm for evaluating this limiting density when the LSD of $A_{p}$ is a
mixture of point masses. In addition, when the entries of $X_{n}$ are
sub-Gaussian, we derive the limiting empirical distribution of
$\{\sqrt{n/p}(\lambda_j(S_n) - n^{-1}\tr(B_n) \lambda_j(A_{p}))\}_{j=1}^p$
where $S_n := n^{-1} A_{p}^{1/2}X_{n}B_{n}X_{n}^{*}A_{p}^{1/2}$ is the sample
covariance matrix and $\lambda_j$ denotes the $j$-th largest eigenvalue, when
$F^A$ is a finite mixture of point masses. These results are utilized to
propose a test for the covariance structure of the data where the null
hypothesis is that the joint covariance matrix is of the form $A_{p} \otimes
B_n$ for $\otimes$ denoting the Kronecker product, as well as $A_{p}$ and the
first two spectral moments of $B_n$ are specified. The performance of this test
is illustrated through a simulation study.


title: WARP: A ICN architecture for social data

abstract:
  Social network companies maintain complete visibility and ownership of the
data they store. However users should be able to maintain full control over
their content. For this purpose, we propose WARP, an architecture based upon
Information-Centric Networking (ICN) designs, which expands the scope of the
ICN architecture beyond media distribution, to provide data control in social
networks. The benefit of our solution lies in the lightweight nature of the
protocol and in its layered design. With WARP, data distribution and access
policies are enforced on the user side. Data can still be replicated in an ICN
fashion but we introduce control channels, named \textit{thread updates}, which
ensures that the access to the data is always updated to the latest control
policy. WARP decentralizes the social network but still offers APIs so that
social network providers can build products and business models on top of WARP.
Social applications run directly on the user's device and store their data on
the user's \textit{butler} that takes care of encryption and distribution.
Moreover, users can still rely on third parties to have high-availability
without renouncing their privacy.


title:
Asymptotic normality in the maximum entropy models on graphs with an
  increasing number of parameters

abstract:
  Maximum entropy models, motivated by applications in neuron science, are
natural generalizations of the $\beta$-model to weighted graphs. Similar to the
$\beta$-model, each vertex in maximum entropy models is assigned a potential
parameter, and the degree sequence is the natural sufficient statistic. Hillar
and Wibisono (2013) has proved the consistency of the maximum likelihood
estimators. In this paper, we further establish the asymptotic normality for
any finite number of the maximum likelihood estimators in the maximum entropy
models with three types of edge weights, when the total number of parameters
goes to infinity. Simulation studies are provided to illustrate the asymptotic
results.


title:
Influence of morphological inhomogeneity induced carrier diffusion on
  transient photocurrent pulse shape in organic thin films

abstract:
  The influence of film morphology induced carrier diffusion on the broadening
of the time-of-flight transient photo-current pulse was investigated using
Monte Carlo simulation in organic thin films. Assuming the Gaussian Disorder
Model for the charge transport the simulation of the time-of-flight
photo-current pulse shape was carried out for homogeneous and inhomogeneous
films by varying the overall energetic disorder of the system. In the case of
homogeneous system, the value of the tail broadening parameter (W) of the
photocurrent pulse is found to decrease upon decreasing the energetic disorder.
The observed behavior is explained by using the temporal evolution of carrier
diffusion coefficient. In case of the inhomogeneous system, upon decreasing the
overall energetic disorder of the system the value of W initially attained a
maximum before it started to decrease. This is attributed to the morphology
dependent carrier diffusion in the latter case. This study elicits the
importance of the influence of the film morphology induced carrier diffusion on
the experimentally measured shape of the time-of-flight transient photo-current
pulses, which is found to be generally ignored.


title: Macroscopic modeling and simulations of room evacuation

abstract:
  We analyze numerically two macroscopic models of crowd dynamics: the
classical Hughes model and the second order model being an extension to
pedestrian motion of the Payne-Whitham vehicular traffic model. The desired
direction of motion is determined by solving an eikonal equation with density
dependent running cost, which results in minimization of the travel time and
avoidance of congested areas. We apply a mixed finite volume-finite element
method to solve the problems and present error analysis for the eikonal solver,
gradient computation and the second order model yielding a first order
convergence. We show that Hughes' model is incapable of reproducing complex
crowd dynamics such as stop-and-go waves and clogging at bottlenecks. Finally,
using the second order model, we study numerically the evacuation of
pedestrians from a room through a narrow exit.


title: Viscous coefficients of a hot pion gas

abstract:
  The steps essentially involved in the evaluation of transport coefficients in
linear response theory using Kubo formulas are to relate the defining {\em
retarded} correlation function to the corresponding {\em time-ordered} one and
to evaluate the latter in the conventional perturbation expansion. Here we
evaluate the viscosities of a pion gas carrying out both the steps in the {\em
real time} formulation. We also obtain the viscous coefficients by solving the
relativistic transport equation in the Chapman-Enskog approximation to leading
order. An in-medium $\pi\pi$ cross-section in used in which spectral
modifications are introduced in the propagator of the exchanged $\rho$.


title: Uncertainties in water chemistry in disks: An application to TW Hya

abstract:
  Context. This paper discusses the sensitivity of water lines to chemical
processes and radiative transfer for the protoplanetary disk around TW Hya. The
study focuses on the Herschel spectral range in the context of new line
detections with the PACS instrument from the Gas in Protoplanetary Systems
project (GASPS). Aims. The paper presents an overview of the chemistry in the
main water reservoirs in the disk around TW Hya. It discusses the limitations
in the interpretation of observed water line fluxes. Methods. ... (abbreviated)
Results. We report new line detections of p-H2O (3_22-2_11) at 89.99 micron and
CO J=18-17 at 144.78 micron for the disk around TW Hya. Disk modeling shows
that the far-IR fine structure lines ([OI], [CII]) and molecular submm lines
are very robust to uncertainties in the chemistry, while the water line fluxes
can change by factors of a few. The water lines are optically thick,
sub-thermally excited and can couple to the background continuum radiation
field. The low-excitation water lines are also sensitive to uncertainties in
the collision rates, e.g. with neutral hydrogen. The gas temperature plays an
important role for the [OI] fine structure line fluxes, the water line fluxes
originating from the inner disk as well as the high excitation CO, CH+ and OH
lines. Conclusions. Due to their sensitivity on chemical input data and
radiative transfer, water lines have to be used cautiously for understanding
details of the disk structure. Water lines covering a wide range of excitation
energies provide access to the various gas phase water reservoirs (inside and
outside the snow line) in protoplanetary disks and thus provide important
information on where gas-phase water is potentially located. Experimental
and/or theoretical collision rates for H2O with atomic hydrogen are needed to
diminish uncertainties from water line radiative transfer.


title:
Pairing strength on the nuclear size in relativistic continuum
  Hartree-Bogoliubov theory

abstract:
  The influence of pairing correlations on the nuclear size and in particular
on the formation of nuclear halos is studied in the framework of relativistic
continuum Hartree-Bogoliubov (RCHB) theory. It turns out that the contributions
from the weakly-bound orbits with low orbital angular momenta $l$ play an
important role. As an example, we investigate the neutron-rich Mg isotopes as a
function of the pairing strength in situations, where the neuron Fermi surface
are below, between and above two weakly-bound $2p$ levels. We find that the
size of the pairing correlations has a two-fold influence on the density
distribution of the neutrons and therefore on the total nuclear size. First it
can change the root mean square (rms) radius of the individual weakly-bound
orbits and second it can enhance the occupation probabilities of these orbits
in the nuclear system. On one side increasing pairing correlations reduce the
rms radii of the orbits with small orbital angular momenta close to the
continuum limit (pairing anti-halo effect), on the other side they also can
lead to an enhanced occupation of low-$l$ orbits above the Fermi surface
producing in this way a strong increase of the total radius of the nuclear
system. As a consequence, a nuclear halo can form even in cases, where non of
the individual low-$l$ orbits is very close to the continuum. This leads to the
fact that compared with well-bound nuclei, the impact of the pairing strength
on the nuclear size is more pronounced in weakly-bound nuclei than in
well-bound systems.