title: Gaussian Sensor Networks with Adversarial Nodes

abstract:
  This paper studies a particular sensor network model which involves one
single Gaussian source observed by many sensors, subject to additive
independent Gaussian observation noise. Sensors communicate with the receiver
over an additive Gaussian multiple access channel. The aim of the receiver is
to reconstruct the underlying source with minimum mean squared error. The
scenario of interest here is one where some of the sensors act as adversary
(jammer): they strive to maximize distortion. We show that the ability of
transmitter sensors to secretly agree on a random event, that is
"coordination", plays a key role in the analysis. Depending on the coordination
capability of sensors and the receiver, we consider two problem settings. The
first setting involves transmitters with coordination capabilities in the sense
that all transmitters can use identical realization of randomized encoding for
each transmission. In this case, the optimal strategy for the adversary sensors
also requires coordination, where they all generate the same realization of
independent and identically distributed Gaussian noise. In the second setting,
the transmitter sensors are restricted to use fixed, deterministic encoders and
this setting, which corresponds to a Stackelberg game, does not admit a
saddle-point solution. We show that the the optimal strategy for all sensors is
uncoded communications where encoding functions of adversaries and transmitters
are in opposite directions. For both settings, digital compression and
communication is strictly suboptimal.


title: Inferring the Origin Locations of Tweets with Quantitative Confidence

abstract:
  Social Internet content plays an increasingly critical role in many domains,
including public health, disaster management, and politics. However, its
utility is limited by missing geographic information; for example, fewer than
1.6% of Twitter messages (tweets) contain a geotag. We propose a scalable,
content-based approach to estimate the location of tweets using a novel yet
simple variant of gaussian mixture models. Further, because real-world
applications depend on quantified uncertainty for such estimates, we propose
novel metrics of accuracy, precision, and calibration, and we evaluate our
approach accordingly. Experiments on 13 million global, comprehensively
multi-lingual tweets show that our approach yields reliable, well-calibrated
results competitive with previous computationally intensive methods. We also
show that a relatively small number of training data are required for good
estimates (roughly 30,000 tweets) and models are quite time-invariant
(effective on tweets many weeks newer than the training set). Finally, we show
that toponyms and languages with small geographic footprint provide the most
useful location signals.


title:
Truncated Infinitesimal Shifts, Spectral Operators and Quantized
  Universality of the Riemann Zeta Function

abstract:
  We survey some of the universality properties of the Riemann zeta function
$\zeta(s)$ and then explain how to obtain a natural quantization of Voronin's
universality theorem (and of its various extensions). Our work builds on the
theory of complex fractal dimensions for fractal strings developed by the
second author and M. van Frankenhuijsen in \cite{La-vF4}. It also makes an
essential use of the functional analytic framework developed by the authors in
\cite{HerLa1} for rigorously studying the spectral operator $\mathfrak{a}$
(mapping the geometry onto the spectrum of generalized fractal strings), and
the associated infinitesimal shift $\partial$ of the real line:
$\mathfrak{a}=\zeta(\partial)$. In the quantization (or operator-valued)
version of the universality theorem for the Riemann zeta function $\zeta(s)$
proposed here, the role played by the complex variable $s$ in the classical
universality theorem is now played by the family of `truncated infinitesimal
shifts' introduced in \cite{HerLa1} to study the invertibility of the spectral
operator in connection with a spectral reformulation of the Riemann hypothesis
as an inverse spectral problem for fractal strings. This latter work provided
an operator-theoretic version of the spectral reformulation obtained by the
second author and H. Maier in \cite{LaMa2}. In the long term, our work (along
with \cite{La5, La6}), is aimed in part at providing a natural quantization of
various aspects of analytic number theory and arithmetic geometry.


title:
An Upper Bound on the Capacity of Vector Dirty Paper with Unknown Spin
  and Stretch

abstract:
  Dirty paper codes are a powerful tool for combating known interference.
However, there is a significant difference between knowing the transmitted
interference sequence and knowing the received interference sequence,
especially when the channel modifying the interference is uncertain. We present
an upper bound on the capacity of a compound vector dirty paper channel where
although an additive Gaussian sequence is known to the transmitter, the channel
matrix between the interferer and receiver is uncertain but known to lie within
a bounded set. Our bound is tighter than previous bounds in the low-SIR regime
for the scalar version of the compound dirty paper channel and employs a
construction that focuses on the relationship between the dimension of the
message-bearing signal and the dimension of the additive state sequence.
Additionally, a bound on the high-SNR behavior of the system is established.


title:
The Higher-Order Heat-Type Equations via signed L\'{e}vy stable and
  generalized Airy functions

abstract:
  We study the higher-order heat-type equation with first time and M-th spatial
partial derivatives, M = 2, 3, ... . We demonstrate that its exact solutions
for M even can be constructed with the help of signed Levy stable functions.
For M odd the same role is played by a special generalization of Airy Ai
function that we introduce and study. This permits one to generate the exact
and explicit heat kernels pertaining to these equations. We examine
analytically and graphically the spacial and temporary evolution of particular
solutions for simple initial conditions.


title:
Vapor-liquid-solid growth of serrated GaN nanowires: Shape selection
  driven by kinetic frustration

abstract:
  Compound semiconducting nanowires are promising building blocks for several
nanoelectronic devices yet the inability to reliably control their growth
morphology is a major challenge. Here, we report the Au-catalyzed
vapor-liquid-solid (VLS) growth of GaN nanowires with controlled growth
direction, surface polarity and surface roughness. We develop a theoretical
model that relates the growth form to the kinetic frustration induced by
variations in the V(N)/III(Ga) ratio across the growing nanowire front. The
model predictions are validated by the trends in the as-grown morphologies
induced by systematic variations in the catalyst particle size and processing
conditions. The principles of shape selection highlighted by our study pave the
way for morphological control of technologically relevant compound
semiconductor nanowires.


title: On the automorphism groups of some AG-codes based on $C_{a, b}$ curves

abstract:
  We study $C_{a, b}$ curves and their applications to coding theory. Recently,
Joyner and Ksir have suggested a decoding algorithm based on the automorphisms
of the code. We show how $C_{a, b}$ curves can be used to construct MDS codes
and focus on some $C_{a, b}$ curves with extra automorphisms, namely
$y^3=x^4+1, y^3=x^4-x, y^3-y=x^4$. The automorphism groups of such codes are
determined in most characteristics.


title: Higher angular momentum pairing from transverse gauge interactions

abstract:
  In this paper, we study superconductivity of nonrelativistic fermions at
finite-density coupled to a transverse $U(1)$ gauge field, with the effective
interaction including the Landau-damping. This model, first studied by
Holstein, Norton, and Pincus [Phys. Rev B, {\bf 8}, 2649 (1973)] has been known
as an example of a non-Fermi liquid, {\i.e.} a metallic state in which the
decay rate of a quasiparticle is large compared to the characteristic
quasiparticle energy; other examples of the non-Fermi liquid includes the 2d
electron gas in a magnetic field at $\nu=1/2$ and the normal state of optimally
doped cuprate superconductors. Our study thus addresses the question of whether
or not non-Fermi liquids, like Fermi liquids, are unstable towards the
formation of superconductivity.The results are (i) the non-Fermi liquid is
stable against superconductivity below a critical gauge coupling, (ii) above
this critical coupling, the ground state is an unconventional superconductor
with angular momentum $\ell \ge 2$. Our results are obtained from a solution of
the Dyson-Nambu equation. Note that in this problem there is a quantum critical
point between a non-Fermi liquid state and the superconducting state, as the
critical coupling is nonzero. This is in contrast to a weakly coupled metal,
which exhibits superconductivity for infinitesimally weak interaction
regardless of its sign.


title:
Analysis Of Interest Points Of Curvelet Coefficients Contributions Of
  Microscopic Images And Improvement Of Edges

abstract:
  This paper focuses on improved edge model based on Curvelet coefficients
analysis. Curvelet transform is a powerful tool for multiresolution
representation of object with anisotropic edge. Curvelet coefficients
contributions have been analyzed using Scale Invariant Feature Transform
(SIFT), commonly used to study local structure in images. The permutation of
Curvelet coefficients from original image and edges image obtained from
gradient operator is used to improve original edges. Experimental results show
that this method brings out details on edges when the decomposition scale
increases.


title: Degree even coverings of elliptic curves by genus 2 curves

abstract:
  In this survey we study the genus 2 curves with $(n, n)$-split Jacobian for
even $n$.


title: Quantum codes from superelliptic curves

abstract:
  Let $\X$ be an algebraic curve of genus $g \geq 2$ defined over a field
$\F_q$ of characteristic $p > 0$. From $\X$, under certain conditions, we can
construct an algebraic geometry code $C$. If the code $C$ is self-orthogonal
under the symplectic product then we can construct a quantum code $Q$, called a
QAG-code. In this paper we study the construction of such codes from curves
with automorphisms and the relation between the automorphism group of the curve
$\X$ and the codes $C$ and $Q$.


title: Density determinations in heavy ion collisions

abstract:
  The experimental determination of freeze-out temperatures and densities from
the yields of light elements emitted in heavy ion collisions is discussed.
Results from different experimental approaches are compared with those of model
calculations carried out with and without the inclusion of medium effects.
Medium effects become of relevance for baryon densities above $\approx 5 \times
10^{-4}$ fm$^{-3}$. A quantum statistical (QS) model incorporating medium
effects is in good agreement with the experimentally derived results at higher
densities. A densitometer based on calculated chemical equilibrium constants is
proposed.


title: The Shared Causal Pasts and Futures of Cosmological Events

abstract:
  We derive criteria for whether two cosmological events can have a shared
causal past or a shared causal future, assuming a
Friedmann-Lemaitre-Robertson-Walker universe with best-fit \Lambda CDM
cosmological parameters from the Planck satellite. We further derive criteria
for whether either cosmic event could have been in past causal contact with our
own worldline since the time of the hot "big bang", which we take to be the end
of early-universe inflation. We find that pairs of objects such as quasars on
opposite sides of the sky with redshifts z >= 3.65 have no shared causal past
with each other or with our past worldline. More complicated constraints apply
if the objects are at different redshifts from each other or appear at some
relative angle less than 180 degrees, as seen from Earth. We present examples
of observed quasar pairs that satisfy all, some, or none of the criteria for
past causal independence. Given dark energy and the recent accelerated
expansion, our observable universe has a finite conformal lifetime, and hence a
cosmic event horizon at current redshift z = 1.87. We thus constrain whether
pairs of cosmic events can signal each other's worldlines before the end of
time. Lastly, we generalize the criteria for shared past and future causal
domains for FLRW universes with nonzero spatial curvature.

categories: astro-ph.CO astro-ph.GA astro-ph.HE gr-qc


title: An exponential lower bound for Cunningham's rule

abstract:
  In this paper we give an exponential lower bound for Cunningham's least
recently considered (round-robin) rule as applied to parity games, Markhov
decision processes and linear programs. This improves a recent subexponential
bound of Friedmann for this rule on these problems. The round-robin rule fixes
a cyclical order of the variables and chooses the next pivot variable starting
from the previously chosen variable and proceeding in the given circular order.
It is perhaps the simplest example from the class of history-based pivot rules.
Our results are based on a new lower bound construction for parity games. Due
to the nature of the construction we are also able to obtain an exponential
lower bound for the round-robin rule applied to acyclic unique sink
orientations of hypercubes (AUSOs). Furthermore these AUSOs are realizable as
polytopes. We believe these are the first such results for history based rules
for AUSOs, realizable or not. The paper is self-contained and requires no
previous knowledge of parity games.


title:
On the Delay-Storage Trade-off in Content Download from Coded
  Distributed Storage Systems

abstract:
  In this paper we study how coding in distributed storage reduces expected
download time, in addition to providing reliability against disk failures. The
expected download time is reduced because when a content file is encoded to add
redundancy and distributed across multiple disks, reading only a subset of the
disks is sufficient to reconstruct the content. For the same total storage
used, coding exploits the diversity in storage better than simple replication,
and hence gives faster download. We use a novel fork-join queuing framework to
model multiple users requesting the content simultaneously, and derive bounds
on the expected download time. Our system model and results are a novel
generalization of the fork-join system that is studied in queueing theory
literature. Our results demonstrate the fundamental trade-off between the
expected download time and the amount of storage space. This trade-off can be
used for design of the amount of redundancy required to meet the delay
constraints on content delivery.


title:
Practical long-distance quantum communication using concatenated
  entanglement swapping

abstract:
  We construct a theory for long-distance quantum communication based on
sharing entanglement through a linear chain of $N$ elementary swapping segments
of length~$L=Nl$ where $l$ is the length of each elementary swap setup.
Entanglement swapping is achieved by linear optics, photon counting and
post-selection, and we include effects due to multi-photon sources,
transmission loss and detector inefficiencies and dark counts. Specifically we
calculate the resultant four-mode state shared by the two parties at the two
ends of the chain, and we derive the two-photon coincidence rate expected for
this state and thereby the visibility of this long-range entangled state. The
expression is a nested sum with each sum extending from zero to infinite
photons, and we solve the case $N=2$ exactly for the ideal case (zero dark
counts, unit-efficiency detectors and no transmission loss) and numerically for
$N=2$ in the non-ideal case with truncation at $n_\text{max}=3$ photons in each
mode. For the general case, we show that the computational complexity for the
numerical solution is $n_\text{max}^{12N}$.


title: On the performance of Usain Bolt in the 100 metre sprint

abstract:
  Many university texts on Mechanics deal with the problem of the effect of the
air drag force, using as example the slowing down of a parachute. Hardly no one
discuss what happens when the drag force is proportional to both $u$ and $u^2$.
In this paper we deal with a real problem to illustrate the effect of both
terms in the speed of a runner: a theoretical model of the performance of the
100 m world record sprint of Usain Bolt during the 2009 World Championships at
Berlin is developed, assuming a drag force proportional to $u$ and to $u^2$.
The resulting equation of motion is solved and fitted to the experimental data
obtained from the International Amateur of Athletics Federations that recorded
Bolt's position with a LAVEG (laser velocity guard) device. It is worth to note
that our model works only for short sprints.


title:
Comments on the thermoelectric power of the f-electron metallic
  compounds

abstract:
  The anomalous temperature variation of the thermoelectric power in the
f-electron metallic compounds, namely the sign reversal or the maxima, is
sometimes interpreted as resulting from the conduction electrons scattering in
Born approximation on the acoustic phonons and on the localized spins in the
s-f exchange interaction. The experimenters rely on the results of some
theoretical works where such thermoelectric power behavior was obtained within
these simple models. In the present paper we prove that neither the
electron-phonon scattering nor the magnetic s-f scattering in the Born
approximation (nor both of them) do lead to the effects mentioned above.


title: Out-of-Equilibrium Chiral Magnetic Effect at Strong Coupling

abstract:
  We study the charge transports originating from triangle anomaly in
out-of-equilibrium conditions in the framework of AdS/CFT correspondence at
strong coupling, to gain useful insights on possible charge separation effects
that may happen in the very early stages of heavy-ion collisions. We first
construct a gravity background of a homogeneous mass shell with a finite
(axial) charge density gravitationally collapsing to a charged blackhole, which
serves as a dual model for out-of-equilibrium charged plasma undergoing
thermalization. We find that a finite charge density in the plasma slows down
the thermalization. We then study the out-of-equilibrium properties of Chiral
Magnetic Effect and Chiral Magnetic Wave in this background. As the medium
thermalizes, the magnitude of chiral magnetic conductivity and the response
time delay grow. We find a dynamical peak in the spectral function of retarded
current correlator, which we identify as an out-of-equilibrium chiral magnetic
wave. The group velocity of the out-of-equilibrium chiral magnetic wave is
shown to receive a dominant contribution from a non-equilibrium effect, making
the wave moving much faster than in the equilibrium, which may enhance the
charge transports via triangle anomaly in the early stage of heavy-ion
collisions.


title:
The $\gamma$-$\alpha$ iso-structural Transition in Cerium, a Critical
  Element

abstract:
  Below the critical temperature $T_c\simeq 600 K$, an iso-structural
transition, named $\gamma$-$\alpha$ transition,can be induced in Cerium by
applying pressure. This transition is first-order, and is accompanied by a
sizable volume collapse. A conclusive theoretical explanation of this
intriguing phenomenon has still not been achieved, and the physical pictures
proposed so far are still under debate. In this work, we illustrate
zero-temperature first-principle calculations which clearly demonstrate that
the $\gamma$-$\alpha$ transition is induced by the interplay between the
electron-electron Coulomb interaction and the spin-orbit coupling. We address
the still unresolved problem on the existence of a second low-$T$ critical
point, i.e., whether the energetic effects alone are sufficient or not to
induce the $\gamma$-$\alpha$ transition at zero temperature.


title: Nash Williams Conjecture and the Dominating Cycle Conjecture

abstract:
  The disproved Nash Williams conjecture states that every 4-regular
4-connected graph has a hamiltonian cycle. We show that a modification of this
conjecture is equivalent to the Dominating Cycle Conjecture.


title: MHD Disc Winds and Linewidth Distributions

abstract:
  We study AGN emission line profiles combining an improved version of the
accretion disc-wind model of Murray & Chiang with the magneto-hydrodynamic
model of Emmering et al. We show how the shape, broadening and shift of the C
IV line depend not only on the viewing angle to the object but also on the wind
launching angle, especially for small launching angles. We have compared the
dispersions in our model C IV linewidth distributions to observational upper
limit on that dispersion, considering both smooth and clumpy torus models. As
the torus half-opening angle (measured from the polar axis) increases above
about 18? degrees, increasingly larger wind launching angles are required to
match the observational constraints. Above a half-opening angle of about 47?
degrees, no wind launch angle (within the maximum allowed by the MHD solutions)
can match the observations. Considering a model that replaces the torus by a
warped disc yields the same constraints obtained with the two other models.


title: An aspherical 5-manifold with perfect fundamental group

abstract:
  We construct aspherical closed orientable 5-manifolds with perfect
fundamental group. This completes part of our study (with D.H.Kochloukova and
I.Lima) of $PD_n$-groups with pro-$p$ completion a pro-$p$ Poincar\'e duality
group of dimension $\leq{n-2}$. We also consider the question of whether there
are any examples with "dimension drop" 1.


title:
Application of vibration-transit theory to distinct dynamic response for
  a monatomic liquid

abstract:
  We examine the distinct part of the density autocorrelation function Fd(q,t),
also called the intermediate scattering function, from the point of view of the
vibration-transit (V-T) theory of monatomic liquid dynamics. A similar study
has been reported for the self part, and we study the self and distinct parts
separately because their damping processes are not simply related. We begin
with the perfect vibrational system, which provides precise definitions of the
liquid correlations, and provides the vibrational approximation Fdvib(q,t) at
all q and t. Two independent liquid correlations are defined, motional and
structural, and these are decorrelated sequentially, with a crossover time
tc(q). This is done by two independent decorrelation processes: the first,
vibrational dephasing, is naturally present in Fdvib(q,t) and operates to damp
the motional correlation; the second, transit-induced decorrelation, is invoked
to enhance the damping of motional correlation, and then to damp the structural
correlation. A microscopic model is made for the "transit drift", the averaged
transit motion that damps motional correlation on 0 < t < tc(q). Following the
previously developed self-decorrelation theory, a microscopic model is also
made for the "transit random walk," which damps the structural correlation on t
> tc(q). The complete model incorporates a property common to both self and
distinct decorrelation: simple exponential decay following a delay period,
where the delay is tc(q, the time required for the random walk to emerge from
the drift. Our final result is an accurate expression for Fd(q,t) for all q
through the first peak in Sd(q). The theory is calibrated and tested using
molecular dynamics (MD) calculations for liquid Na at 395K; however, the theory
itself does not depend on MD, and we consider other means for calibrating it.


title: Quantum Energy Teleportation without Limit of Distance

abstract:
  Quantum energy teleportation (QET) is, from an operational viewpoint of
distant protocol users, the transportation of energy via local operations and
classical communication. QET has various links to fundamental research fields,
including black hole physics, the quantum theory of Maxwell's demon, and
condensed-matter entanglement. There are promising signs that QET will be
experimentally verified using the chiral boson fields of quantum Hall edge
currents. In this Letter, we prove that, using the vacuum state of a quantum
field, the upper bound of the amount of energy teleported by QET is inversely
proportional to the transfer distance. This distance bound can be overcome by
using squeezed states with local-vacuum regions.


title:
Graphene-Dielectric Composite Metamaterials: Evolution from Elliptic to
  Hyperbolic Wavevector Dispersion and The Transverse Epsilon-Near-Zero
  Condition

abstract:
  We investigated a multilayer graphene-dielectric composite material,
comprising graphene sheets separated by subwavelength-thick dielectric spacer,
and found it to exhibit hyperbolic isofrequency wavevector dispersion at far-
and mid-infrared frequencies allowing propagation of waves that would be
otherwise evanescent in a dielectric. Electrostatic biasing was considered for
tunable and controllable transition from hyperbolic to elliptic dispersion. We
explored the validity and limitation of the effective medium approximation
(EMA) for modeling wave propagation and cutoff of the propagating spatial
spectrum due to the Brillouin zone edge. We found that EMA is capable of
predicting the transition of the isofrequency dispersion diagram under certain
conditions. The graphene-based composite material allows propagation of
backward waves under the hyperbolic dispersion regime and of forward waves
under the elliptic regime. Transition from hyperbolic to elliptic dispersion
regimes is governed by the transverse epsilon-near-zero (TENZ) condition, which
implies a flatter and wider propagating spectrum with higher attenuation, when
compared to the hyperbolic regime. We also investigate the tunable transparency
of the multilayer at that condition in contrast to other materials exhibiting
ENZ phenomena.


title:
Quantum Limits of Interferometer Topologies for Gravitational Radiation
  Detection

abstract:
  In order to expand the astrophysical reach of gravitational wave detectors,
several interferometer topologies have been proposed to evade the thermodynamic
and quantum mechanical limits in future detectors. In this work, we make a
systematic comparison among them by considering their sensitivities and
complexities. We numerically optimize their sensitivities by introducing a cost
function that tries to maximize the broadband improvement over the sensitivity
of current detectors. We find that frequency-dependent squeezed-light injection
with a hundred-meter scale filter cavity yields a good broadband sensitivity,
with low complexity, and good robustness against optical loss. This study gives
us a guideline for the near-term experimental research programs in enhancing
the performance of future gravitational-wave detectors.


title:
Critical behavior of the fidelity susceptibility for the d=2
  transverse-field Ising model

abstract:
  The overlap (inner product) between the ground-state eigenvectors with
proximate interaction parameters, the so-called fidelity, plays a significant
role in the quantum-information theory. In this paper, the critical behavior of
the fidelity susceptibility is investigated for the two-dimensional
tranverse-field (quantum) Ising model by means of the numerical diagonalization
method. In order to treat a variety of system sizes N=12,14,...,32, we adopt
the screw-boundary condition. Finite-size artifacts (scaling corrections) of
the fidelity susceptibility appear to be suppressed, as compared to those of
the Binder parameter. As a result, we estimate the fidelity-susceptibility
critical exponent as \alpha_F =0.715(20).


title:
Spectral Efficiency and Energy Efficiency of OFDM Systems: Impact of
  Power Amplifiers and Countermeasures

abstract:
  In wireless communication systems, the nonlinear effect and inefficiency of
power amplifier (PA) have posed practical challenges for system designs to
achieve high spectral efficiency (SE) and energy efficiency (EE). In this
paper, we analyze the impact of PA on the SE-EE tradeoff of orthogonal
frequency division multiplex (OFDM) systems. An ideal PA that is always linear
and incurs no additional power consumption can be shown to yield a decreasing
convex function in the SE-EE tradeoff. In contrast, we show that a practical PA
has an SE-EE tradeoff that has a turning point and decreases sharply after its
maximum EE point. In other words, the Pareto-optimal tradeoff boundary of the
SE-EE curve is very narrow. A wide range of SE-EE tradeoff, however, is desired
for future wireless communications that have dynamic demand depending on the
traffic loads, channel conditions, and system applications, e.g.,
high-SE-with-low-EE for rate-limited systems and high-EE-with-low-SE for
energy-limited systems. For the SE-EE tradeoff improvement, we propose a PA
switching (PAS) technique. In a PAS transmitter, one or more PAs are switched
on intermittently to maximize the EE and deliver an overall required SE. As a
consequence, a high EE over a wide range SE can be achieved, which is verified
by numerical evaluations: with 15% SE reduction for low SE demand, the PAS
between a low power PA and a high power PA can improve EE by 323%, while a
single high power PA transmitter improves EE by only 68%.


title: A combinatorial version of the colorful Caratheodory theorem

abstract:
  We give the following extension of Barany's colorful Caratheodory theorem:
Let M be an oriented matroid and N a matroid with rank function r, both defined
on the same ground set V and satisfying rank(M) < rank(N). If every subset A of
V with r(V - A) < rank (M) contains a positive circuit of M, then some
independent set of N contains a positive circuit of M.


title: The combinatorics of scattering in layered media

abstract:
  Reflection and transmission of waves in piecewise constant layered media are
important in various imaging modalities and have been studied extensively.
Despite this, no exact time domain formulas for the Green's functions have been
established. Indeed, there is an underlying combinatorial obstacle: the
analysis of scattering sequences. In the present paper we exploit a
representation of scattering sequences in terms of trees to solve completely
the inherent combinatorial problem, and thereby derive new, explicit formulas
for the reflection and transmission Green's functions.


title:
Spectroscopy of a Cooper-Pair Box Coupled to a Two-Level System Via
  Charge and Critical Current

abstract:
  We report on the quadrupling of the transition spectrum of an Al/AlOx/Al
Cooper-pair box (CPB) charge qubit in the 4.0-7.3 GHz frequency range. The
qubit was coupled to a quasi-lumped element Al superconducting resonator and
measured at a temperature of 25 mK. We obtained good matches between the
observed spectrum and the spectra calculated from a model Hamiltonian
containing two distinct low excitation energy two-level systems (TLS) coupled
to the CPB. In our model, each TLS has a charge that tunnels between two sites
in a local potential and induces a change in the CPB critical current. By
fitting the model to the spectrum, we have extracted microscopic parameters of
the fluctuators including the well asymmetry, tunneling rate, and a
surprisingly large fractional change (30-40%) in the critical current (12 nA).
This large change is consistent with a Josephson junction with a non-uniform
tunnel barrier containing a few dominant conduction channels and a TLS that
modulates one of them.


title:
Parity violation in nuclear magnetic resonance frequencies of chiral
  tetrahedral tungsten complexes NWXYZ (X, Y, Z = H, F, Cl, Br or I)

abstract:
  Density functional theory within the two-component quasi-relativistic
zeroth-order regular approximation (ZORA) is used to predict parity violation
shifts in 183W nuclear magnetic resonance shielding tensors of chiral,
tetrahedrally bonded tungsten complexes of the form NWXYZ (X, Y, Z = H, F, Cl,
Br or I). The calculations reveal that sub-mHz accuracy is required to detect
such tiny effects in this class of compounds, and that parity violation effects
are very sensitive to the choice of ligands.


title: Powerful terahertz emission from Bi2Sr2CaCu2O8+delta mesa arrays

abstract:
  Stacks of intrinsic Josephson junctions (IJJs) in high-temperature
superconductors enable the fabrication of compact sources of coherent terahertz
radiation. Here we demonstrate that multiple stacks patterned on the same
Bi2Sr2CaCu2O8+delta crystal can - under optimized conditions - be synchronized
to emit high-power THz-radiation. For three synchronized stacks we achieved 610
microwatts of continuous-wave coherent radiation power at 0.51 THz. We suggest
that synchronization is promoted by THz-waves in the base crystal. We note
though that synchronization cannot be achieved in all samples. However, even in
these cases powers on the 100-microwatt scale can be generated.


title:
Asymptotic Expressions for Charge Matrix Elements of the Fluxonium
  Circuit

abstract:
  In charge-coupled circuit QED systems, transition amplitudes and dispersive
shifts are governed by the matrix elements of the charge operator. For the
fluxonium circuit, these matrix elements are not limited to nearest-neighbor
energy levels and are conveniently tunable by magnetic flux. Previously, their
values were largely obtained numerically. Here, we present analytical
expressions for the fluxonium charge matrix elements. We show that new
selection rules emerge in the asymptotic limit of large Josephson energy and
small inductive energy. We illustrate the usefulness of our expressions for the
qualitative understanding of charge matrix elements in the parameter regime
probed by previous experiments.

categories: cond-mat.mes-hall cond-mat.supr-con physics.atom-ph quant-ph


title:
Dynamic effects in double graphene-layer structures with inter-layer
  resonant-tunneling negative conductivity

abstract:
  We study the dynamic effects in the double graphene-layer (GL) structures
with the resonant-tunneling (RT) and the negative differential inter-GL
conductivity. Using the developed model, which accounts for the excitation of
self-consistent oscillations of the electron and hole densities and the ac
electric field between GLs (plasma oscillations),
  we calculate the admittance of the double-GL RT structures as a function of
the signal frequency and applied voltages, and the spectrum and
increment/decrement of plasma oscillations. Our results show that the
electron-hole plasma in the double-GL RT structures with realistic parameters
is stable with respect to the self-excitation of plasma oscillations and
aperiodic perturbations. The stability of the electron-hole plasma at the bias
voltages corresponding to the inter-GL RT and strong nonlinearity of the RT
current-voltage characteristics enable using the double-GL RT structures for
detection of teraherz (THz) radiation. The excitation of plasma oscillations by
the incoming THz radiation can result in a sharp resonant dependence of
detector responsivity on radiation frequency and the bias voltage. Due to a
strong nonlinearity of the current-voltage characteristics of the double-GL
structures at RT and the resonant excitation of plasma oscillations, the
maximum responsivity, $R_V^{max}$, can markedly exceed the values $(10^4 -
10^5)$~V/W at room temperature.


title:
A solution for an inverse problem in liquid AFM: calculation of
  three-dimensional solvation structure on a sample surface

abstract:
  Recent frequency-modulated atomic force microscopy (FM-AFM) can measure
three-dimensional force distribution between a probe and a sample surface in
liquid. The force distribution is, in the present circumstances, assumed to be
solvation structure on the sample surface, because the force distribution and
solvation structure have somewhat similar shape. However, the force
distribution is exactly not the solvation structure. If we would like to obtain
the solvation structure by using the liquid AFM, a method for transforming the
force distribution into the solvation structure is necessary. Therefore, in
this letter, we present the transforming method in a brief style. We call this
method as a solution for an inverse problem, because the solvation structure is
obtained at first and the force distribution is obtained next in general
calculation processes. The method is formulated (mainly) by statistical
mechanics of liquid.

categories: physics.data-an physics.bio-ph physics.chem-ph physics.comp-ph


title:
Accurate densities of states for disordered systems from free
  probability: Live Free or Diagonalize

abstract:
  We investigate how free probability allows us to approximate the density of
states in tight binding models of disordered electronic systems. Extending our
previous studies of the Anderson model in neighbor interactions [J. Chen et
al., Phys. Rev. Lett. 109, 036403 (2012)], we find that free probability
continues to provide accurate approximations for systems with constant
interactions on two- and three-dimensional lattices or with
next-nearest-neighbor interactions, with the results being visually
indistinguishable from the numerically exact solution. For systems with
disordered interactions, we observe a small but visible degradation of the
approximation. To explain this behavior of the free approximation, we develop
and apply an asymptotic error analysis scheme to show that the approximation is
accurate to the eighth moment in the density of states for systems with
constant interactions, but is only accurate to sixth order for systems with
disordered interactions. The error analysis also allows us to calculate
asymptotic corrections to the density of states, allowing for systematically
improvable approximations as well as insight into the sources of error without
requiring a direct comparison to an exact solution.


title: Two-Hop Interference Channels: Impact of Linear Time-Varying Schemes

abstract:
  We consider the two-hop interference channel (IC) with constant real channel
coefficients, which consists of two source-destination pairs, separated by two
relays. We analyze the achievable degrees of freedom (DoF) of such network when
relays are restricted to perform scalar amplify-forward (AF) operations, with
possibly time-varying coefficients. We show that, somewhat surprisingly, by
providing the flexibility of choosing time-varying AF coefficients at the
relays, it is possible to achieve 4/3 sum-DoF. We also develop a novel outer
bound that matches our achievability, hence characterizing the sum-DoF of
two-hop interference channels with time-varying AF relaying strategies.


title: Internal-cycle variation of solar differential rotation

abstract:
  The latitudinal distributions of the yearly mean rotation rates measured
respectively by Suzuki in 1998 and 2012 and Pulkkinen $\&$ Tuominen in 1998 are
utilized to investigate internal-cycle variation of solar differential
rotation. The rotation rate at the solar Equator seems to decrease since cycle
10 onwards. The coefficient $B$ of solar differential rotation, which
represents the latitudinal gradient of rotation, is found smaller in the
several years after the minimum of a solar cycle than in the several years
after the maximum time of the cycle, and it peaks several years after the
maximum time of the solar cycle. The internal-cycle variation of the solar
rotation rates looks similar in profile to that of the coefficient $B$. A new
explanation is proposed to address such a solar-cycle related variation of the
solar rotation rates. Weak magnetic fields may more effectively reflect
differentiation at low latitudes with high rotation rates than at high
latitudes with low rotation rates, and strong magnetic fields may more
effectively repress differentiation at relatively low latitudes than at high
latitudes. The internal-cycle variation is inferred to the result of both the
latitudinal migration of the surface torsional pattern and the repression of
strong magnetic activity to differentiation.


title: Sparse Norm Filtering

abstract:
  Optimization-based filtering smoothes an image by minimizing a fidelity
function and simultaneously preserves edges by exploiting a sparse norm penalty
over gradients. It has obtained promising performance in practical problems,
such as detail manipulation, HDR compression and deblurring, and thus has
received increasing attentions in fields of graphics, computer vision and image
processing. This paper derives a new type of image filter called sparse norm
filter (SNF) from optimization-based filtering. SNF has a very simple form,
introduces a general class of filtering techniques, and explains several
classic filters as special implementations of SNF, e.g. the averaging filter
and the median filter. It has advantages of being halo free, easy to implement,
and low time and memory costs (comparable to those of the bilateral filter).
Thus, it is more generic than a smoothing operator and can better adapt to
different tasks. We validate the proposed SNF by a wide variety of applications
including edge-preserving smoothing, outlier tolerant filtering, detail
manipulation, HDR compression, non-blind deconvolution, image segmentation, and
colorization.


title: Multiplicity one for $L$-functions and applications

abstract:
  We give conditions for when two Euler products are the same given that they
satisfy a functional equation and their coefficients satisfy a partial
Ramanujan bound and do not differ by too much. Additionally, we prove a number
of multiplicity one type results for the number-theoretic objects attached to
$L$-functions. These results follow from our main result about $L$-functions.


title:
Invariants of (-1)-Skew Polynomial Rings under Permutation
  Representations

abstract:
  The symmetric group S_n acts on the skew polynomial ring A=k_{-1}[x_1,...,
x_n] as permutations. For subgroups G of S_n we consider properties of the ring
of invariants A^G. We show that A^G is always Artin-Schelter Gorenstein, and we
investigate when A^G is a "complete intersection", in a sense we define. We
obtain bounds on the degrees of the algebra generators. The properties of A^G
are compared with those in the classical case, k[x_1, ..., x_n]^G.


title:
Higher order corrections to adiabatic invariants of generalized
  slow-fast Hamiltonian systems

abstract:
  We present a coordinate-free approach for constructing approximate first
integrals of generalized slow-fast Hamiltonian systems, based on the global
averaging method on parameter-dependent phase spaces with $\mathbb{S}^1
-$symmetry. Explicit global formulas for approximate second-order first
integrals are derived. As examples, we analyze the case quadratic in the fast
variables (in particular, the elastic pendulum), and the charged particle in a
slowly-varying magnetic field.


title: Coherent State Quantum Key Distribution with Entanglement Witnessing

abstract:
  An entanglement witness approach to quantum coherent state key distribution
and a system for its practical implementation are described. In this approach,
eavesdropping can be detected by a change in sign of either of two witness
functions, an entanglement witness S or an eavesdropping witness W. The effects
of loss and eavesdropping on system operation are evaluated as a function of
distance. Although the eavesdropping witness W does not directly witness
entanglement for the system, its behavior remains related to that of the true
entanglement witness S. Furthermore, W is easier to implement experimentally
than S. W crosses the axis at a finite distance, in a manner reminiscent of
entanglement sudden death. The distance at which this occurs changes measurably
when an eavesdropper is present. The distance dependance of the two witnesses
due to amplitude reduction and due to increased variance resulting from both
ordinary propagation losses and possible eavesdropping activity is provided.
Finally, the information content and secure key rate of a continuous variable
protocol using this witness approach are given.


title:
An efficient parallel immersed boundary algorithm using a
  pseudo-compressible fluid solver

abstract:
  We propose an efficient algorithm for the immersed boundary method on
distributed-memory architectures, with the computational complexity of a
completely explicit method and excellent parallel scaling. The algorithm
utilizes the pseudo-compressibility method recently proposed by Guermond and
Minev [Comptes Rendus Mathematique, 348:581-585, 2010] that uses a directional
splitting strategy to discretize the incompressible Navier-Stokes equations,
thereby reducing the linear systems to a series of one-dimensional tridiagonal
systems. We perform numerical simulations of several fluid-structure
interaction problems in two and three dimensions and study the accuracy and
convergence rates of the proposed algorithm. For these problems, we compare the
proposed algorithm against other second-order projection-based fluid solvers.
Lastly, the strong and weak scaling properties of the proposed algorithm are
investigated.


title:
Invariant Gaussian processes and independent sets on regular graphs of
  large girth

abstract:
  We prove that every 3-regular, n-vertex simple graph with sufficiently large
girth contains an independent set of size at least 0.4361n. (The best known
bound is 0.4352n.) In fact, computer simulation suggests that the bound our
method provides is about 0.438n.
  Our method uses invariant Gaussian processes on the d-regular tree that
satisfy the eigenvector equation at each vertex for a certain eigenvalue
\lambda. We show that such processes can be approximated by i.i.d. factors
provided that $|\lambda| \leq 2\sqrt{d-1}$. We then use these approximations
for $\lambda = -2\sqrt{d-1}$ to produce factor of i.i.d. independent sets on
regular trees.


title:
A Conceptual E-Governance Framework for Improving Child Immunization
  Process in India

abstract:
  India is country having high population and great variations in the
educational level, economic conditions, population densities, cultures and
awareness levels. Due to these variations the immunization process is not so
much successful as per expectations of the state and central governments. In
some zones the significant amount of vaccines are wasted whereas some are
running out of vaccines. One of the reasons for such an imbalance is improper
quantity estimation of vaccines in a particular zone. Further a huge amount of
liquidity will be wasted in the form of vaccines. If we inculcate ICT
(Information and Communication Technology) in the process of immunization then
the problem can be rectified to some extent and hence we are proposing a
conceptual model using ICT to improve the process of vaccination.


title:
Comparative Study of Electronic structure of New Superconductors
  (Sr,Ca)Pd2As2 and related compound BaPd2As2

abstract:
  This paper presents the comparative study of LDA calculated electronic
structure of new isostructural to iron based systems superconductors
(Sr,Ca)Pd2As2 with Tc about 1K and similar but structurally different system
BaPd2As2. Despite chemical formula looks similar to iron superconductors and
even main structural motif is the same - layers of Fe square lattices,
electronic structure of (Sr,Ca)Pd2As2 and BaPd2As2 differs from Fe(As,Se)-HTSC
completely. All these systems have essentially three dimensional Fermi surfaces
in contrast to Fe(As,Se) materials. The Fermi level is crossed by low intensive
tails of Pd-4d and As-4p states. However (Sr,Ca)Pd2As2 and BaPd2As2 materials
have rather well developed peaks of Pd-4d(x2-y2) band. Thus by doping of about
2 holes per unit cell one can increase density of states at the Fermi level by
a factor about 2.5. Since experimentally these compounds were found to be
simple BCS superconductors the hole doping may considerably increase Tc. LDA
calculated total densities of states at the Fermi level for stoichiometric
systems perfectly agree with experimental estimates signifying rather small
role of electronic correlations.


title:
Linking reduced breaking crest speeds to unsteady nonlinear water wave
  group behavior

abstract:
  Observations show that maximally-steep breaking water wave crest speeds are
much slower than expected. We report a wave-crest slowdown mechanism generic to
unsteady propagating deep water wave groups. Our fully nonlinear computations
show that just prior to reaching its maximum height, each wave crest slows down
significantly and either breaks at this reduced speed, or accelerates forward
unbroken. This finding is validated in our extensive laboratory and field
observations. This behavior appears to be generic to unsteady dispersive wave
groups in other natural systems.


title: Binary Tree based Chinese Word Segmentation

abstract:
  Chinese word segmentation is a fundamental task for Chinese language
processing. The granularity mismatch problem is the main cause of the errors.
This paper showed that the binary tree representation can store outputs with
different granularity. A binary tree based framework is also designed to
overcome the granularity mismatch problem. There are two steps in this
framework, namely tree building and tree pruning. The tree pruning step is
specially designed to focus on the granularity problem. Previous work for
Chinese word segmentation such as the sequence tagging can be easily employed
in this framework. This framework can also provide quantitative error analysis
methods. The experiments showed that after using a more sophisticated tree
pruning function for a state-of-the-art conditional random field based
baseline, the error reduction can be up to 20%.


title:
The derivative discontinuity in the strong-interaction limit of density
  functional theory

abstract:
  We generalize the exact strong-interaction limit of the exchange-correlation
energy of Kohn-Sham density functional theory to open systems with fluctuating
particle numbers. When used in the self-consistent Kohn-Sham procedure on
strongly-interacting systems, this functional yields exact features crucial for
important applications such as electronic transport. In particular, the
step-like structure of the highest-occupied Kohn-Sham eigenvalue is very well
captured, with accurate quantitative agreement with exact many-body chemical
potentials. Whilst it can be shown that a sharp derivative discontinuity is
only present in the infinitely strong-correlated limit, at finite correlation
regimes we observe a slightly-smoothened discontinuity, with qualitative and
quantitative features that improve with increasing correlation. From the
fundamental point of view, our results obtain the derivative discontinuity
without making the assumptions used in its standard derivation, offering
independent support for its existence.


title:
Elongation of energy exchange between femtosecond laser pulses via
  plasma formation in air

abstract:
  We experimentally demonstrate energy exchange between a delay-tuned
femtosecond beam and two delay-fixed ones as they spatiotemporally overlapped
and experienced filamentation in air. The energy exchange process in the
relative time delay is dramatically elongated up to 40 ps in the presence of
plasma grating, indicating that filamentary beams coupling may be an effective
method for filament control.


title: Chiral extrapolations for nucleon electric charge radii

abstract:
  Lattice simulations for the electromagnetic form factors of the nucleon yield
insights into the internal structure of hadrons. The logarithmic divergence of
the charge radius in the chiral limit poses an interesting challenge in
achieving reliable predictions from finite-volume lattice simulations. Recent
results near the physical pion mass are examined in order to confront the issue
of how the chiral regime is approached. The electric charge radius of the
nucleon presents a forum for achieving consistent finite-volume corrections.
Newly-developed techniques within the framework of chiral effective field
theory are used to achieve a robust extrapolation of the electric charge radius
to the physical pion mass, and to infinite volume. The chiral extrapolations
exhibit considerable finite-volume dependence; lattice box sizes of L > 7 fm
are required in order to achieve a direct lattice simulation result within 2%
of the infinite-volume value at the physical point. Predictions of the
volume-dependence are provided to guide the interpretation of future lattice
results.


title: String Models, Stability and Regge Trajectories for Hadron States

abstract:
  Various string models of mesons and baryons include a string carrying 2 or 3
massive points (quarks or antiquarks). Rotational states (planar uniform
rotations) of these systems generate quasilinear Regge trajectories and may be
used for describing excited hadron states on these trajectories. For different
string models of baryon we are to solve the problem of choice between them and
the stability problem for their rotational states. An unexpected result is that
for the Y string baryon model these rotations are unstable with respect to
small disturbances on the classical level. This instability has specific
feature, disturbances grow linearly, whereas for the linear string baryon model
they grow exponentially and may increase predictions for baryon's width
$\Gamma$. The classical instability of rotational states and nonstandard Regge
slope are the arguments in favor of the stable simplest model of string with
massive ends both for baryons and mesons. Rotational states of this model with
two types of spin-orbit correction are used to describe Regge trajectories for
light, strange, charmed, bottom mesons and for $N$, $\Delta$, $\Sigma$,
$\Lambda$ and $\Lambda_c$ baryons.


title: Ubiquitous nucleosome unwrapping in the yeast genome

abstract:
  Nucleosome core particle is a dynamic structure -- DNA may transiently peel
off the histone octamer surface due to thermal fluctuations or the action of
chromatin remodeling enzymes. Partial DNA unwrapping enables easier access of
DNA-binding factors to their target sites and thus may provide a dominant
pathway for effecting rapid and robust access to DNA packaged into chromatin.
Indeed, a recent high-resolution map of distances between neighboring
nucleosome dyads in \emph{S.cerevisiae} shows that at least 38.7\% of all
nucleosomes are partially unwrapped. The extent of unwrapping follows a
stereotypical pattern in the vicinity of genes, reminiscent of the canonical
pattern of nucleosome occupancy in which nucleosomes are depleted over
promoters and well-positioned over coding regions. To explain these
observations, we developed a biophysical model which employs a 10-11 base pair
periodic nucleosome energy profile. The profile, based on the pattern of
histone-DNA contacts in nucleosome crystal structures and the idea of linker
length discretization, accounts for both nucleosome unwrapping and higher-order
chromatin structure. Our model reproduces the observed genome-wide distribution
of inter-dyad distances, and accounts for patterns of nucleosome occupancy and
unwrapping around coding regions. At the same time, our approach explains
\emph{in vitro} measurements of accessibility of nucleosome-covered binding
sites, and of nucleosome-induced cooperativity between DNA-binding factors. We
are able to rule out several alternative scenarios of nucleosome unwrapping as
inconsistent with the genomic data.


title: New mass limit of white dwarfs

abstract:
  Is the Chandrasekhar mass limit for white dwarfs (WDs) set in stone? Not
anymore -- recent observations of over-luminous, peculiar type Ia supernovae
can be explained if significantly super-Chandrasekhar WDs exist as their
progenitors, thus barring them to be used as cosmic distance indicators.
However, there is no estimate of a mass limit for these super-Chandrasekhar WD
candidates yet. Can they be arbitrarily large? In fact, the answer is no! We
arrive at this revelation by exploiting the flux freezing theorem in observed,
accreting, magnetized WDs, which brings in Landau quantization of the
underlying electron degenerate gas. This essay presents the calculations which
pave the way for the ultimate (significantly super-Chandrasekhar) mass limit of
WDs, heralding a paradigm shift 80 years after Chandrasekhar's discovery.


title: A First-Order BSPDE for Swing Option Pricing

abstract:
  We study an optimal control problem related to swing option pricing in a
general non-Markovian setting in continuous time. As a main result we show that
the value process solves a first-order non-linear backward stochastic partial
differential equation. Based on this result we can characterize the set of
optimal controls and derive a dual minimization problem.


title: Predicting the variance of a measurement with 1/f noise

abstract:
  Measurement devices always add noise to the signal of interest and it is
necessary to evaluate the variance of the results. This article focuses on
stationary random processes whose Power Spectrum Density is a power law of
frequency. For flicker noise, behaving as $1/f$ and which is present in many
different phenomena, the usual way to compute the variance leads to infinite
values. This article proposes an alternative definition of the variance which
takes into account the fact that measurement devises need to be calibrated.
This new variance, which depends on the calibration duration, the measurement
duration and the duration between the calibration and the measurement, allows
avoiding infinite values when computing the variance of a measurement.


title:
Polaronic transport induced by competing interfacial magnetic order in a
  La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ heterostructure

abstract:
  Using ultrafast optical spectroscopy, we show that polaronic behavior
associated with interfacial antiferromagnetic order is likely the origin of
tunable magnetotransport upon switching the ferroelectric polarity in a
La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ (LCMO/BFO) heterostructure. This is
revealed through the difference in dynamic spectral weight transfer between
LCMO and LCMO/BFO at low temperatures, which indicates that transport in
LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases
in relatively high magnetic fields due to the increased spin alignment, while
no discernible change is found in the LCMO film at low temperatures. These
results thus shed new light on the intrinsic mechanisms governing
magnetoelectric coupling in this heterostructure, potentially offering a new
route to enhancing multiferroic functionality.


title:
Observations of very high energy gamma-ray emission from AGNs with the
  ground-based EAS arrays

abstract:
  The ground-based EAS array is usually operated with a high duty cycle (> 90%)
and a large field of view (~2 sr), which can continuously monitor the sky. It
is essential and irreplaceable to understand the gamma-ray emission mechanism
and intrinsic physics progress of the variable source AGN. The EAS arrays, AS-r
experiment (since 1990) and ARGO-YBJ experiment (since 2007), have continuously
monitored the northern sky at energies above 3 TeV and 0.3 TeV, respectively.
They have made substantial contributions for long-term monitoring of Mrk 421
and Mrk 501. In this paper, we will review the results obtained by the EAS
arrays. The next generation of EAS array, LHAASO project, will boost the
sensitivity of current EAS array at least up to 30 times with a much wider
energy range from 40 GeV to 1 PeV. Beside increasing the number of VHE
gamma-ray sources, it will guide us look sight into the properties of jet, and
throw light on the determining of the EBL, intergalactic magnetic fields, and
the validity of the Lorentz Invariance.


title: Exact Abelian and Non-Abelian Geometric Phases

abstract:
  The existence of Hopf fibrations S^{2N+1}/S^1 = CP^N and S^{4K+3}/S^3 = HP^K
allows us to treat the Hilbert space of generic finite-dimensional quantum
systems as the total bundle space with respectively $U(1)$ and $SU(2)$ fibers
and complex and quaternionic projective spaces as base manifolds. This
alternative method of studying quantum states and their evolution reveals the
intimate connection between generic quantum mechanical systems and geometrical
objects. The exact Abelian and non-Abelian geometric phases, and more generally
the geometrical factors for open paths, and their precise correspondence with
geometric Kahler and hyper-Kahler connections will be discussed. Explicit
physical examples are used to verify and exemplify the formalism.


title: The defocusing energy-supercritical NLS in four space dimensions

abstract:
  We consider a class of defocusing energy-supercritical nonlinear
Schr\"odinger equations in four space dimensions. Following a
concentration-compactness approach, we show that for $1<s_c<3/2$, any solution
that remains bounded in the critical Sobolev space $\dot{H}_x^{s_c}(\R^4)$ must
be global and scatter. Key ingredients in the proof include a long-time
Strichartz estimate and a frequency-localized interaction Morawetz inequality.


title:
Defect energetics and electronic structures of As-doped p-type ZnO
  crystals: A first-principles study

abstract:
  First-principles calculations based on density functional theory have been
carried out to understand the mechanism of fabricating As-doped p-type ZnO
semiconductors. It has been confirmed that AsZn-2VZn complex is the most
plausible acceptor among several candidates for p-type doping by computing the
formation and ionization energies. The electronic band structures and
atomic-projected density of states of AsZn-2VZn defect complex-contained ZnO
bulks have been computed. The acceptor level in AsZn-2VZn band structure has
found to be 0.12 eV, which is in good agreement with the experimental
ionization energy (0.12 ~ 0.18 eV). The hybridization among O 2p, Zn 3d and As
4s states has been observed around the valence band maximum.


title:
Precursor phenomena of nucleations of quantized vortices in the presence
  of a uniformly moving obstacle in Bose-Einstein condensates

abstract:
  We investigate excitations and fluctuations of Bose-Einstein condensates in a
two-dimensional torus with a uniformly moving Gaussian potential by solving the
Gross-Pitaevskii equation and the Bogoliubov equation. The energy gap $\Delta$
between the current-flowing metastable state (that reduces to the ground state
for sufficiently slowly-moving potential) and the first excited state vanishes
when the moving velocity $v$ of the potential approaches a critical velocity
v_c(>0). We find a scaling law $\Delta \propto (1-|v|/v_c)^{1/4}$, which
implies that a characteristic time scale diverges toward the critical velocity.
Near the critical velocity, we show that low-energy local density fluctuations
are enhanced. These behaviors can be regarded as precursor phenomena of the
vortex nucleation.


title: Probing the BFKL Pomeron with Future ATLAS Forward Detectors

abstract:
  The Jet-Gap-Jet (JGJ) process as a way to test the
Balitsky-Fadin-Kuraev-Lipatov Pomeron is introduced. The comparison with the
Tevatron data as well as the predictions for the LHC are presented. In the
second part, the possibility to measure the Double Pomeron Exchange (DPE)
Jet-Gap-Jet process in the ATLAS experiment with additional AFP detectors is
described. The ratio of the DPE jet-gap-jet cross section to the DPE jet cross
section is presented.


title:
Supernovae in the Central Parsec: A Mechanism for Producing Spatially
  Anisotropic Hypervelocity Stars

abstract:
  Several tens of hyper-velocity stars (HVSs) have been discovered escaping our
Galaxy. These stars share a common origin in the Galactic centre and are
distributed anisotropically in Galactic longitude and latitude. We examine the
possibility that HVSs may be created as the result of supernovae occurring
within binary systems in a disc of stars around Sgr A* over the last 100 Myr.
Monte Carlo simulations show that the rate of binary disruption is ~10^-4
yr^-1, comparable to that of tidal disruption models. The supernova-induced HVS
production rate (\Gamma_HVS) is significantly increased if the binaries are
hardened via migration through a gaseous disc. Moderate hardening gives
\Gamma_HVS ~ 2*10^-7 yr^-1 and an estimated population of ~20 HVSs in the last
100 Myr. Supernova-induced HVS production requires the internal and external
orbital velocity vectors of the secondary binary component to be aligned when
the binary is disrupted. This leaves an imprint of the disc geometry on the
spatial distribution of the HVSs, producing a distinct anisotropy.


title:
CW frequency doubling of 1029 nm radiation Using single pass bulk and
  waveguide PPLN crystals

abstract:
  Following various works on second harmonic process using periodically poled
Lithium Niobate crystals (PPLN), we report on the performances comparison
between commercial bulk and waveguide crystals at 1029 nm. We use a continuous
wave (CW) amplified Yb doped single fibre laser delivering up to 500mW in
single mode regime. In case of bulk crystal we generate 4 mW using 400 mW IR
power. The use of waveguide crystal leads to an increase of the harmonic power
up to 33mW with input IR power limited to 200mW. Nevertheless, this impressive
efficiency was affected by the long term degradation of the non-linear
waveguide crystal.


title:
Complete infrared spectral energy distributions of mm detected quasars
  at z>5

abstract:
  We present Herschel far-infrared (FIR) photometry of eleven quasars at
redshift z>5 that have previously been detected at 1.2mm. We perform full
spectral energy distribution (SED) fits over the wavelength range lambda_rest
~0.1-400mu for those objects with good Herschel detections. These fits reveal
the need for an additional far-infrared (FIR) component besides the emission
from a dusty AGN-powered torus. This additional FIR component has temperatures
of T_FIR ~ 40-60K with luminosities of L_(8-1000mu) ~ 10^13 L_sun (accounting
for 25-60% of the bolometric FIR luminosity). If the FIR dust emission is due
to star formation it would suggest star formation rates in excess of 1000 solar
masses per year. We show that at long wavelengths (lambda_rest > 50mu) the
contribution of the AGN-powered torus emission is negligible. This explains how
previous FIR studies of high-redshift quasars that relied on single component
fits to (ground-based) observations at lambda_obs > 350mu reached T_FIR and
L_FIR values similar to our complete SED fits. Stacking the Herschel data of
four individually undetected sources reveals a significant average signal in
the PACS bands but not in SPIRE. The average SED of sources with individual
Herschel detections shows a striking surplus in near- and mid-infrared emission
when compared to common AGN templates. The comparison between two average SEDs
(sources with and without individual Herschel detections) matched in the
UV/optical indicates that for these objects the strength of the MIR emission
may correlate with the strength of the FIR emission.


title:
Reducing Revenue to Welfare Maximization: Approximation Algorithms and
  other Generalizations

abstract:
  It was recently shown in [http://arxiv.org/abs/1207.5518] that revenue
optimization can be computationally efficiently reduced to welfare optimization
in all multi-dimensional Bayesian auction problems with arbitrary (possibly
combinatorial) feasibility constraints and independent additive bidders with
arbitrary (possibly combinatorial) demand constraints. This reduction provides
a poly-time solution to the optimal mechanism design problem in all auction
settings where welfare optimization can be solved efficiently, but it is
fragile to approximation and cannot provide solutions to settings where welfare
maximization can only be tractably approximated. In this paper, we extend the
reduction to accommodate approximation algorithms, providing an approximation
preserving reduction from (truthful) revenue maximization to (not necessarily
truthful) welfare maximization. The mechanisms output by our reduction choose
allocations via black-box calls to welfare approximation on randomly selected
inputs, thereby generalizing also our earlier structural results on optimal
multi-dimensional mechanisms to approximately optimal mechanisms. Unlike
[http://arxiv.org/abs/1207.5518], our results here are obtained through novel
uses of the Ellipsoid algorithm and other optimization techniques over {\em
non-convex regions}.


title: C^\infty-logarithmic transformations and generalized complex structures

abstract:
  Applying logarithmic transformations along 2-tori, we construct a generalized
complex structure J_n with n type changing luci for every $n\geq 0$ on genus
1-Lefschetz fibrations with a cusp neighborhood, which include elliptic
surfaces with non-zero euler characteristic. Applying a technique of broken
Lefschetz fibrations, we further obtain twisted generalized complex structures
with arbitrary large numbers of connected components of type changing loci on
the manifold which is obtained from a symplectic manifold by logarithmic
transformations of multiplicity 0 on a symplectic 2-torus with trivial normal
bundle. The connected sums $(2m+1)S^2\times S^2$ for $m\geq 0$, $(2n-1)\C P^2#
(10n-1)\ol{\C P^2}$ and $S^1\times S^3$ admit twisted generalized complex
structures J_n with n type changing luci for arbitrary large n.


title: Understanding Incentives: Mechanism Design becomes Algorithm Design

abstract:
  We provide a computationally efficient black-box reduction from mechanism
design to algorithm design in very general settings. Specifically, we give an
approximation-preserving reduction from truthfully maximizing \emph{any}
objective under \emph{arbitrary} feasibility constraints with \emph{arbitrary}
bidder types to (not necessarily truthfully) maximizing the same objective plus
virtual welfare (under the same feasibility constraints). Our reduction is
based on a fundamentally new approach: we describe a mechanism's behavior
indirectly only in terms of the expected value it awards bidders for certain
behavior, and never directly access the allocation rule at all.
  Applying our new approach to revenue, we exhibit settings where our reduction
holds \emph{both ways}. That is, we also provide an approximation-sensitive
reduction from (non-truthfully) maximizing virtual welfare to (truthfully)
maximizing revenue, and therefore the two problems are computationally
equivalent. With this equivalence in hand, we show that both problems are
NP-hard to approximate within any polynomial factor, even for a single monotone
submodular bidder.
  We further demonstrate the applicability of our reduction by providing a
truthful mechanism maximizing fractional max-min fairness. This is the first
instance of a truthful mechanism that optimizes a non-linear objective.


title: Quiver Grassmannians and Auslander varieties for wild algebras

abstract:
  Let k be an algebraically closed field and A a finite-dimensional k-algebra.
Given an A-module M, the set G_e(M) of all submodules of M with dimension
vector e is called a quiver Grassmannian. If D,Y are A-modules, then we
consider Hom(D,Y) as a B-module, where B is the opposite of the endomorphism
ring of D, and the Auslander varieties for A are the quiver Grassmannians of
the form G_e Hom(D,Y). Quiver Grassmannians, thus also Auslander varieties are
projective varieties and it is known that every projective variety occurs in
this way. There is a tendency to relate this fact to the wildness of quiver
representations and the aim of this note is to clarify these thoughts: We show
that for an algebra A which is (controlled) wild, any projective variety can be
realized as an Auslander variety, but not necessarily as a quiver Grassmannian.


title: The Fragility of Quantum Information?

abstract:
  We address the question whether there is a fundamental reason why quantum
information is more fragile than classical information. We show that some
answers can be found by considering the existence of quantum memories and their
dimensional dependence.


title: Excessive [l,m]-factorizations

abstract:
  Given two positive integers l and m, with l \le m, an [l,m]-covering of a
graph G is a set M of matchings of G whose union is the edge set of G and such
that l \le |L| \le m for every matching L of M. An [l,m]-covering M of G is an
excessive [l,m]-factorization of G if the cardinality of M is as small as
possible. The number of matchings in an excessive [l,m]-factorization of G (or
\infty, if G does not admit an excessive [l,m]-factorization) is a graph
parameter called the excessive [l,m]-index of G and denoted by \chi'[l,m](G).
In this paper we study such parameter. Our main result is a general formula for
the excessive [l,m]-index of a graph G in terms of other graph parameters.
Furthermore, we give a polynomial time algorithm which computes \chi'[l,m](G)
and outputs an excessive [l,m]-factorization of G, whenever the latter exists.


title:
Diffusion of solar magnetic elements up to supergranular spatial and
  temporal scales

abstract:
  The study of spatial and temporal scales on which small magnetic structures
(magnetic elements) are organized in the quiet Sun may be approached by
determining how they are transported on the solar photosphere by convective
motions. The process involved is diffusion. Taking advantage of Hinode high
spatial resolution magnetograms of a quiet Sun region at the disk center, we
tracked 20145 magnetic elements. The large field of view (~50 Mm) and the long
duration of the observations (over 25 hours without interruption at a cadence
of 90 seconds) allowed us to investigate the turbulent flows at unprecedented
large spatial and temporal scales. In the field of view, in fact, an entire
supergranule is clearly recognizable. The magnetic elements displacement
spectrum shows a double-regime behavior: superdiffusive (gamma=1.34 +/- 0.02)
up to granular spatial scales (~1500 km), and slightly superdiffusive
(gamma=1.20 +/- 0.05) up to supergranular scales.


title:
The electron-ion streaming instabilities driven by drift velocities of
  the order of electron thermal velocity in a nonmagnetized plasma

abstract:
  We examine the electron-ion streaming instabilities driven by drift
velocities of the order of the electron thermal velocity in a nonmagnetized
plasma by one-dimensional electrostatic particle-in-cell code which adopts an
ion-to-electron mass ratio of 1600. An initial state is set up where the ion
bulk speed is zero while the electrons drift relative to ions, and where
electrons are much hotter. We examine in detail four runs where drift velocity
is systematically varied from lower than to larger than the electron thermal
velocity. In all runs the Langmuir waves with Doppler-shifted frequencies
dominate early on when streaming instabilities are too weak to discern. And
then intense ion-acoustic waves or Buneman instabilities appear, which tend to
be accompanied by localized electron and ion beams. Ion-acoustic modes and
Buneman modes co-exist in the system when the initial drift velocity is just
over the electron thermal speed. Beam modes are excited when the localized
beams with large enough velocities appear. In the developed stage of
instabilities, the direction in which density depressions propagate is always
opposite to that of the localized ion beams. When the initial drift velocity is
close to the electron thermal speed, categorizing the relevant instabilities is
not easy, and one needs to examine in detail the wave dispersion diagrams at
various stages of the evolution of the system.


title:
Exact Recovery Conditions for Sparse Representations with Partial
  Support Information

abstract:
  We address the exact recovery of a k-sparse vector in the noiseless setting
when some partial information on the support is available. This partial
information takes the form of either a subset of the true support or an
approximate subset including wrong atoms as well. We derive a new sufficient
and worst-case necessary (in some sense) condition for the success of some
procedures based on lp-relaxation, Orthogonal Matching Pursuit (OMP) and
Orthogonal Least Squares (OLS). Our result is based on the coherence "mu" of
the dictionary and relaxes the well-known condition mu<1/(2k-1) ensuring the
recovery of any k-sparse vector in the non-informed setup. It reads
mu<1/(2k-g+b-1) when the informed support is composed of g good atoms and b
wrong atoms. We emphasize that our condition is complementary to some
restricted-isometry based conditions by showing that none of them implies the
other.
  Because this mutual coherence condition is common to all procedures, we carry
out a finer analysis based on the Null Space Property (NSP) and the Exact
Recovery Condition (ERC). Connections are established regarding the
characterization of lp-relaxation procedures and OMP in the informed setup.
First, we emphasize that the truncated NSP enjoys an ordering property when p
is decreased. Second, the partial ERC for OMP (ERC-OMP) implies in turn the
truncated NSP for the informed l1 problem, and the truncated NSP for p<1.


title: Cat state, sub-Planck structure and weak measurement

abstract:
  Heisenberg-limited and weak measurements are the two intriguing notions, used
in recent times for enhancing the sensitivity of measurements in quantum
metrology. Using a quantum cat state, endowed with sub-Planck structure, we
connect these two novel concepts. It is demonstrated that these two phenomena
manifest in complementary regimes, depending upon the degree of overlap between
the mesoscopic states constituting the cat state under consideration. In
particular, we find that when sub-Planck structure manifests, the imaginary
weak value is obscured and vice-versa.


title: Matrix G-Strands

abstract:
  We discuss three examples in which one may extend integrable
Euler--Poincar\'e ODEs to integrable Euler--Poincar\'e PDEs in the matrix
G-Strand context. After describing matrix G-Strand examples for $SO(3)$ and
$SO(4)$ we turn our attention to $SE(3)$ where the matrix G-Strand equations
recover the exact rod theory in the convective representation. We then find a
zero curvature representation (ZCR) of these equations and establish the
conditions under which they are completely integrable. Thus, the G-Strand
equations turn out to be a rich source of integrable systems. The treatment is
meant to be expository and most concepts are explained in examples in the
language of vectors in $\mathbb{R}^3$.


title: Bott-Chern cohomology and q-complete domains

abstract:
  In studying the Bott-Chern and Aeppli cohomologies for q-complete manifolds,
we introduce the class of cohomologically Bott-Chern q-complete manifolds.


title: On the support of a body by a surface with random roughness

abstract:
  Suppose an interval is put on a horizontal line with random roughness. With
probability one it is supported at two points, one from the left, and another
from the right from its center. We compute probability distribution of support
points provided the roughness is fine grained. We also solve an analogous
problem where a circle is put on a rough plane. Some applications in static are
given.


title: A market impact game under transient price impact

abstract:
  We consider a Nash equilibrium between two high-frequency traders in a simple
market impact model with transient price impact and additional quadratic
transaction costs. Extending a result by Sch\"oneborn (2008), we prove
existence and uniqueness of the Nash equilibrium and show that for small
transaction costs the high-frequency traders engage in a "hot-potato game", in
which the same asset position is sold back and forth. We then identify a
critical value for the size of the transaction costs above which all
oscillations disappear and strategies become buy-only or sell-only. Numerical
simulations show that for both traders the expected costs can be lower with
transaction costs than without. Moreover, the costs can increase with the
trading frequency when there are no transaction costs, but decrease with the
trading frequency when transaction costs are sufficiently high. We argue that
these effects occur due to the need of protection against predatory trading in
the regime of low transaction costs.


title: Exponential random graph models for networks with community structure

abstract:
  Although the community structure organization is one of the most important
characteristics of real-world networks, the traditional network models fail to
reproduce the feature. Therefore, the models are useless as benchmark graphs
for testing community detection algorithms. They are also inadequate to predict
various properties of real networks. With this paper we intend to fill the gap.
We develop an exponential random graph approach to networks with community
structure. To this end we mainly built upon the idea of blockmodels. We
consider both, the classical blockmodel and its degree-corrected counterpart,
and study many of their properties analytically. We show that in the
degree-corrected blockmodel, node degrees display an interesting scaling
property, which is reminiscent of what is observed in real-world fractal
networks. The scaling feature comes as a surprise, especially that in this
study, contrary to what is suggested in the literature, the scaling property is
not attributed to any specific network construction procedure. It is an
intrinsic feature of the degree-corrected blockmodel. A short description of
Monte Carlo simulations of the models is also given in the hope of being useful
to others working in the field.


title:
Nonlinear propagation of polarized light pulses in a medium of atoms
  with degenerate energy levels: adiabatic approach

abstract:
  We develop a general method allowing one to construct the consistent theory
of light pulse propagation through an atomic medium in arbitrary nonlinear
regime with respect to the field strength, taking into account the light
polarization, temporal (frequency) and spatial dispersions. The method is based
on the reduced Maxwell equation, atomic density matrix formalism and adiabatic
approximation. In order to demonstrate the efficiency of our method we
investigate in detail the case of propagation of the polarization pulse under
conditions of coherent population trapping in a medium of two-level atoms with
degenerate energy levels. Equations describing the evolution of various field
parameters are derived. It is shown that pulses of ellipticity and spatial
orientation of polarization ellipse propagate with slowing. Analytical
expressions for the slowing factor are obtained. A previously unknown effects
of the stimulated phase modulation and the generation of a phase pilot pulse by
the variation of spatial orientation of the polarization ellipse are predicted.
In addition, we show that the spatial dispersion can be interpreted as "wind
effects".


title: A calculation of $L$-series in terms of Jacobi sums

abstract:
  Let us consider a cyclic extension of a function field defined over a finite
field. For a character (non-trivial) of this extension, we calculate, as a
linear combinations of products of Jacobi sums, the coefficients of the
polynomial given by its Dirichtlet $L$-series.
  In the last section we show applications of this calculation.


title:
Probable detection of HI at $z\simeq 1.3$ from DEEP2 galaxies using the
  GMRT

abstract:
  We have observed the DEEP2 galaxies using the Giant Meterwave Radio Telescope
in the frequency band of 610 MHz. There are $\simeq 400$ galaxies in the
redshift range $1.24 < z < 1.36$ and within the field of view
  $\simeq 44'$, of the GMRT dishes. We have coadded the HI 21 cm-line emissions
at the locations of these DEEP2 galaxies. We apply stacking on three different
data cubes: primary beam uncorrected, primary beam corrected (uniform weighing
) and primary beam corrected (optimal weighing).
  We obtain a peak signal strength in the range $8\hbox{--}25 \, \rm
\mu$Jy/beam for a velocity width in the range $270\hbox{--} 810 \, \rm km \,
sec^{-1}$. The error on the signal, computed by bootstrapping, lies in the
range $2.5\hbox{--}6 \, \rm \mu$Jy/beam, implying a 2.5--4.7-$\sigma$
  detection of the signal at $z \simeq 1.3$. We compare our results with N-body
simulations of the
  signal at $z\simeq 1$ and find reasonable agreement. We also discuss the
impact of residual continuum and systematics.


title:
A Peep on the Interplays between Online Video Websites and Online Social
  Networks

abstract:
  Many online video websites provide the shortcut links to facilitate the video
sharing to other websites especially to the online social networks (OSNs). Such
video sharing behavior greatly changes the interplays between the two types of
websites. For example, users in OSNs may watch and re-share videos shared by
their friends from online video websites, and this can also boost the
popularity of videos in online video websites and attract more people to watch
and share them. Characterizing these interplays can provide great insights for
understanding the relationships among online video websites, OSNs, ISPs and so
on. In this paper we conduct empirical experiments to study the interplays
between video sharing websites and OSNs using three totally different data
sources: online video websites, OSNs, and campus network traffic. We find that,
a) there are many factors that can affect the external sharing probability of
videos in online video websites. b) The popularity of a video itself in online
video websites can greatly impact on its popularity in OSNs. Videos in Renren,
Qzone (the top two most popular Chinese OSNs) usually attract more viewers than
in Sina and Tencent Weibo (the top two most popular Chinese microblogs), which
indicates the different natures of the two kinds of OSNs. c) The analysis based
on real traffic data illustrates that 10\% of video flows are related to OSNs,
and they account for 25\% of traffic generated by all videos.


title: Bifurcation and symmetry breaking for the H\'enon equation

abstract:
  In this paper we consider the H\'enon problem in a ball. We prove the
existence of (at least) one branch of nonradial solutions that bifurcate from
the radial ones and that this branch is unbounded.


title:
Implications of 98 GeV and 125 GeV Higgs scenario in non-decoupling SUSY
  with updated ATLAS, CMS and PLANCK data

abstract:
  We discuss both MSSM and NMSSM scenarios in which the lightest Higgs boson
with $m_h=98$~GeV is consistent with the small excess ($\sim 2.3 \sigma$)
observed at the LEP in $e^+ e^-\rightarrow Zh$, with $h \rightarrow b {\bar b}$
process and the heavier Higgs boson of mass close to 125~GeV as the observed
candidate of the SM Higgs like particle at the LHC. We show the allowed regions
in the non-decoupling Higgs zone of MSSM parameter space which are consistent
with several low energy constraints coming from heavy flavour physics, latest
experimental data on Higgs signals and lower limit on superparticle masses from
7~TeV and 8~TeV LHC run. We also implement the constraints from the relic
density of the cold dark matter as obtained from the recent PLANCK data.
Additionally, we discuss the possibility of observing the light Higgs boson of
mass 98~GeV at the 14~TeV LHC run via $pp \rightarrow V h$, with $h \rightarrow
b \bar b$ using the technique of jet substructure. Our analysis shows that at
14~TeV LHC run with 300 ${\rm fb}^{-1}$ luminosity the signal efficiency of
such a light Higgs boson is at most 2.5$\sigma$. Finally, we make a comment on
the prospect of proposed $e^+ e^-$ ILC to discover/exclude this light Higgs
boson.


title:
Bcl-2 family controls mitochondrial outer membrane permeabilization by
  performing non-trivial pattern recognition

abstract:
  Interactions between individual members of the B-cell lymphoma 2 (Bcl-2)
family of proteins form a regulatory network governing mitochondrial outer
membrane permeabilization (MOMP). Bcl-2 family initiated MOMP causes release of
the inter-membrane pro-apoptotic proteins to cytosol and creates a cytosolic
environment suitable for the executionary phase of apoptosis. Using
mathematical modeling and computational simulation, we have analyzed the
response of this regulatory network caused by the up-/downregulation of each
individual member of the Bcl-2 family. As a result, a non-linear
stimulus-response emerged, the characteristics of which are associated with
bistability and switch-like behavior. Using the principal component analysis
(PCA) we have shown that the Bcl-2 family classifies the random combinations of
inputs into two distinct classes, and responds to these by one of the two
qualitatively distinct outputs. As we showed, the emergence of this behavior
requires specific organization of the interactions between particular Bcl-2
proteins.


title:
Bayesian Test for Colocalisation Between Pairs of Genetic Association
  Studies Using Summary Statistics

abstract:
  Genetic association studies, in particular the genome-wide association study
design, have provided a wealth of novel insights into the aetiology of a wide
range of human diseases and traits. The next challenge consists of
understanding the molecular basis of these associations. The integration of
multiple association datasets, including gene expression datasets, can
contribute to this goal. We have developed a novel statistical methodology to
assess whether two association signals are consistent with a shared causal
variant. An application is the integration of disease scans with expression
quantitative trait locus (eQTL) studies, but any pair of GWAS datasets can be
integrated in this framework. We demonstrate the value of the approach by
reanalysing a gene expression dataset in 966 liver samples with a published
meta-analysis of lipid traits including >100, 000 individuals of European
ancestry. Combining all lipid biomarkers, our reanalysis supported 29 out of 38
reported colocalisation results with eQTLs and identified 14 new colocalisation
results, highlighting the value of a formal statistical test. In two cases of
reported eQTL-lipid pairs (IFT172, TBKBP1) for which our analysis suggests that
the eQTL pattern is not consistent with the lipid association, we identify
alternative colocalisation results with GCKR and KPNB1, indicating that these
genes are more likely to be causal in these genomic intervals. A key feature of
the method is the ability to derive the output statistics from single SNP
summary statistics, hence making it possible to perform systematic
meta-analysis type comparisons across multiple GWAS datasets
(http://coloc.cs.ucl.ac.uk/coloc/). Our methodology provides information about
candidate causal genes in associated intervals and has direct implications for
the understanding of complex diseases and the design of drugs to target disease
pathways.


title:
Novel integrable higher-dimensional nonlinear Schroedinger equation:
  properties, solutions, applications

abstract:
  An integrable extension of the well known nonlinear Schroedinger (NLS)
equation to a higher space-dimension, recently proposed by us, is investigated,
exploring its various important aspects. Focusing on the idea of construction
its connection with other known models like the Zakharov equation and the
Strachan construction is shown. The underlying integrable structures like the
Lax pair, the infinite conserved charges and the higher soliton solutions are
presented in the explicit form. The related 2D rogue wave model and other
applications are focused on.


title:
Spin and energy relaxation in germanium studied by spin-polarized
  direct-gap photoluminescence

abstract:
  Spin orientation of photoexcited carriers and their energy relaxation is
investigated in bulk Ge by studying spin-polarized recombination across the
direct band gap. The control over parameters such as doping and lattice
temperature is shown to yield high polarization degree, namely larger than 40%,
as well as a fine-tuning of the angular momentum of the emitted light with a
complete reversal between right- and left-handed circular polarization. By
combining the measurement of the optical polarization state of band-edge
luminescence and Monte Carlo simulations of carrier dynamics, we show that
these very rich and complex phenomena are the result of the electron
thermalization and cooling in the multi-valley conduction band of Ge. The
circular polarization of the direct-gap radiative recombination is indeed
affected by energy relaxation of hot electrons via the X valleys and the
Coulomb interaction with extrinsic carriers. Finally, thermal activation of
unpolarized L valley electrons accounts for the luminescence depolarization in
the high temperature regime.


title:
A topological obstruction for small-distortion embeddability into spaces
  of continuous functions on countable compact metric spaces

abstract:
  We give the first lower bound on the $\scr C(K)$-distortion of the class of
separable Banach spaces, for $K$ a countable compact in the family $\{
[0,\omega],[0,\omega\cdot2],\cdots, [0,\omega^2], \cdots, [0,\omega^k\cdot
n],\cdots,[0,\omega^\omega]\}$.


title: On local equivalence of star-products on Poisson manifolds

abstract:
  We present a proof that every star-product defined on a Poisson manifold and
written in a given quantum canonical coordinate system is uniquely equivalent
with a Moyal product associated with this coordinate system. The equivalence is
assumed to satisfy some additional conditions which guarantee its uniqueness.
Moreover, the systematic construction of such equivalence is presented and a
formula for this equivalence in a case of a particular class of star-products
is given, to the fourth order in $\hbar$.


title:
Efficient random coordinate descent algorithms for large-scale
  structured nonconvex optimization

abstract:
  In this paper we analyze several new methods for solving nonconvex
optimization problems with the objective function formed as a sum of two terms:
one is nonconvex and smooth, and another is convex but simple and its structure
is known. Further, we consider both cases: unconstrained and linearly
constrained nonconvex problems. For optimization problems of the above
structure, we propose random coordinate descent algorithms and analyze their
convergence properties. For the general case, when the objective function is
nonconvex and composite we prove asymptotic convergence for the sequences
generated by our algorithms to stationary points and sublinear rate of
convergence in expectation for some optimality measure. Additionally, if the
objective function satisfies an error bound condition we derive a local linear
rate of convergence for the expected values of the objective function. We also
present extensive numerical experiments for evaluating the performance of our
algorithms in comparison with state-of-the-art methods.


title: A remark on the radial minimizer of the Ginzburg-Landau functional

abstract:
  Denote by $E_\epsilon$ the Ginzburg-Landau functional in the plane and let
$\tilde u_\varepsilon$ be the radial solution to the Euler equation associated
to the problem $\min \left\{E_\varepsilon(u,B_1): \>\left. u\right\vert
_{\partial B_{1}}=(\cos \vartheta,\sin \vartheta)\right\}$. Let $\Omega\subset
\R^2$ be a smooth, bounded domain with the same area as $B_1$. Denoted by
$$\mathcal{K}=\left\{v=(v_1,v_2) \in H^1(\Omega;\R^2):\> \int_\Omega
v_1\,dx=\int_\Omega v_2\,dx=0,\> \int_\Omega |v|^2\,dx\ge \int_{B_1} |\tilde
u_\varepsilon|^2\,dx\right\},$$
  we prove $$ \min_{v \in \mathcal{K}} E_\varepsilon (v,\Omega)\le
E_\varepsilon (\tilde u_\varepsilon,B_1). $$


title: Computability vs. Nondeterministic and P vs. NP

abstract:
  This paper demonstrates the relativity of Computability and Nondeterministic;
the nondeterministic is just Turing's undecidable Decision rather than the
Nondeterministic Polynomial time.
  Based on analysis about TM, UM, DTM, NTM, Turing Reducible, beta-reduction,
P-reducible, isomorph, tautology, semi-decidable, checking relation, the oracle
and NP-completeness, etc., it reinterprets The Church-Turing Thesis that is
equivalent of the Polynomial time and actual time; it redefines the NTM based
on its undecidable set of its internal state. It comes to the conclusions: The
P-reducible is misdirected from the Turing Reducible with its oracle; The
NP-completeness is a reversal to The Church-Turing Thesis; The Cook-Levin
theorem is an equipollent of two uncertains. This paper brings forth new
concepts: NP (nondeterministic problem) and NP-algorithm (defined as the
optimal algorithm to get the best fit approximation value of NP). P versus NP
is the relativity of Computability and Nondeterministic, P/=NP. The
NP-algorithm is effective approximate way to NP by TM.


title:
Traveling Wave Solutions for Delayed Reaction-Diffusion Systems and
  Applications to Lotka-Volterra Competition-Diffusion Models with Distributed
  Delays

abstract:
  This paper is concerned with the traveling wave solutions of delayed
reaction-diffusion systems. By using Schauder's fixed point theorem, the
existence of traveling wave solutions is reduced to the existence of
generalized upper and lower solutions. Using the technique of contracting
rectangles, the asymptotic behavior of traveling wave solutions for delayed
diffusive systems is obtained. To illustrate our main results, the existence,
nonexistence and asymptotic behavior of positive traveling wave solutions of
diffusive Lotka-Volterra competition systems with distributed delays are
established. The existence of nonmonotone traveling wave solutions of diffusive
Lotka-Volterra competition systems is also discussed. In particular, it is
proved that if there exists instantaneous self-limitation effect, then the
large delays appearing in the intra-specific competitive terms may not affect
the existence and asymptotic behavior of traveling wave solutions.


title: Traveling Wave Solutions for Integro-Difference Systems

abstract:
  This paper is concerned with the traveling wave solutions for
integro-difference systems of higher order. By using Schauder fixed point
theorem, the existence of traveling wave solutions is reduced to the existence
of generalized upper and lower solutions. Then the asymptotic behavior of
traveling wave solutions is studied by the idea of contracting rectangles. To
illustrate our results, the traveling wave solutions of three systems are
considered, which completes some known results.