title:
Termination Criteria for Solving Concurrent Safety and Reachability
  Games

abstract:
  We consider concurrent games played on graphs. At every round of a game, each
player simultaneously and independently selects a move; the moves jointly
determine the transition to a successor state. Two basic objectives are the
safety objective to stay forever in a given set of states, and its dual, the
reachability objective to reach a given set of states. We present in this paper
a strategy improvement algorithm for computing the value of a concurrent safety
game, that is, the maximal probability with which player~1 can enforce the
safety objective. The algorithm yields a sequence of player-1 strategies which
ensure probabilities of winning that converge monotonically to the value of the
safety game.
  Our result is significant because the strategy improvement algorithm
provides, for the first time, a way to approximate the value of a concurrent
safety game from below. Since a value iteration algorithm, or a strategy
improvement algorithm for reachability games, can be used to approximate the
same value from above, the combination of both algorithms yields a method for
computing a converging sequence of upper and lower bounds for the values of
concurrent reachability and safety games. Previous methods could approximate
the values of these games only from one direction, and as no rates of
convergence are known, they did not provide a practical way to solve these
games.


title: Megabits secure key rate quantum key distribution

abstract:
  Quantum cryptography (QC) can provide unconditional secure communication
between two authorized parties based on the basic principles of quantum
mechanics. However, imperfect practical conditions limit its transmission
distance and communication speed. Here we implemented the differential phase
shift (DPS) quantum key distribution (QKD) with up-conversion assisted hybrid
photon detector (HPD) and achieved 1.3 M bits per second secure key rate over a
10-km fiber, which is tolerant against the photon number splitting (PNS)
attack, general collective attacks on individual photons, and any other known
sequential unambiguous state discrimination (USD) attacks.


title: Throughput Scaling of Wireless Networks With Random Connections

abstract:
  This work studies the throughput scaling laws of ad hoc wireless networks in
the limit of a large number of nodes. A random connections model is assumed in
which the channel connections between the nodes are drawn independently from a
common distribution. Transmitting nodes are subject to an on-off strategy, and
receiving nodes employ conventional single-user decoding. The following results
are proven:
  1) For a class of connection models with finite mean and variance, the
throughput scaling is upper-bounded by $O(n^{1/3})$ for single-hop schemes, and
$O(n^{1/2})$ for two-hop (and multihop) schemes.
  2) The $\Theta (n^{1/2})$ throughput scaling is achievable for a specific
connection model by a two-hop opportunistic relaying scheme, which employs
full, but only local channel state information (CSI) at the receivers, and
partial CSI at the transmitters.
  3) By relaxing the constraints of finite mean and variance of the connection
model, linear throughput scaling $\Theta (n)$ is achievable with Pareto-type
fading models.


title:
First-order phase transitions: A study through the parallel tempering
  method

abstract:
  We study the applicability of the {\it parallel tempering method} (PT) in the
investigation of first- order phase transitions. In this method, replicas of
the same system are simulated simultaneously at different temperatures and the
configurations of two randomly chosen replicas can occasionally be
interchanged. We apply the PT for the Blume-Emery-Griffiths (BEG) model, which
displays strong first-order transitions at low temperatures. A precise estimate
of coexistence lines is obtained, revealing that the PT may be a successful
tool for the characterization of discontinuous transitions.


title: Motion of the hot spot and spin torque in accreting millisecond pulsars

abstract:
  The primary concern of this contribution is that accreting millisecond
pulsars (AMXPs) show a much larger amount of information than is commonly
believed. The three questions to be addressed are: 1. Is the apparent spin
torque observed in AMXPs real ? 2. Why do we see correlations and
anti-correlations between fractional amplitudes and timing residuals in some
AMXPs ? 3. Why the timing residuals, the lightcurve and the 1Hz QPO in SAX
J1808.4$-$3658 are related ?


title:
Exploration of Effective Potential Landscapes using Coarse Reverse
  Integration

abstract:
  We describe a reverse integration approach for the exploration of
low-dimensional effective potential landscapes. Coarse reverse integration
initialized on a ring of coarse states enables efficient "navigation" on the
landscape terrain: escape from local effective potential wells, detection of
saddle points, and identification of significant transition paths between
wells. We consider several distinct ring evolution modes: backward stepping in
time, solution arc--length, and effective potential. The performance of these
approaches is illustrated for a deterministic problem where the energy
landscape is known explicitly. Reverse ring integration is then applied to
"noisy" problems where the ring integration routine serves as an outer
"wrapper" around a forward-in-time inner simulator. Three versions of such
inner simulators are considered: a system of stochastic differential equations,
a Gillespie--type stochastic simulator, and a molecular dynamics simulator. In
these "equation-free" computational illustrations, estimation techniques are
applied to the results of short bursts of "inner" simulation to obtain the
unavailable (in closed form) quantities (local drift and diffusion coefficient
estimates) required for reverse ring integration; this naturally leads to
approximations of the effective landscape.


title:
Obtaining pressure versus concentration phase diagrams in spin systems
  from Monte Carlo simulations

abstract:
  We propose an efficient procedure for determining phase diagrams of systems
that are described by spin models. It consists of combining cluster algorithms
with the method proposed by Sauerwein and de Oliveira where the grand canonical
potential is obtained directly from the Monte Carlo simulation, without the
necessity of performing numerical integrations. The cluster algorithm presented
in this paper eliminates metastability in first order phase transitions
allowing us to locate precisely the first-order transitions lines. We also
produce a different technique for calculating the thermodynamic limit of
quantities such as the magnetization whose infinite volume limit is not
straightforward in first order phase transitions. As an application, we study
the Andelman model for Langmuir monolayers made of chiral molecules that is
equivalent to the Blume-Emery-Griffiths spin-1 model. We have obtained the
phase diagrams in the case where the intermolecular forces favor interactions
between enantiomers of the same type (homochiral interactions). In particular,
we have determined diagrams in the surface pressure versus concentration plane
which are more relevant from the experimental point of view and less usual in
numerical studies.


title: The Inconvenient Truth About Coronal Dimmings

abstract:
  We investigate the occurrence of a CME-driven coronal dimming using unique
high resolution spectral images of the corona from the Hinode spacecraft. Over
the course of the dimming event we observe the dynamic increase of non-thermal
line broadening in the 195.12Angstrom emission line of Fe XII as the corona
opens. As the corona begins to close, refill and brighten, we see a reduction
of the non-thermal broadening towards the pre-eruption level. We propose that
the dynamic evolution of non-thermal broadening is the result of the growth of
Alfven wave amplitudes in the magnetically open rarefied dimming region,
compared to the dense closed corona prior to the CME. We suggest, based on this
proposition, that, as open magnetic regions, coronal dimmings must act just as
coronal holes and be sources of the fast solar wind, but only temporarily.
Further, we propose that such a rapid transition in the thermodynamics of the
corona to a solar wind state may have an impulsive effect on the CME that
initiates the observed dimming. This last point, if correct, poses a
significant physical challenge to the sophistication of CME modeling and
capturing the essence of the source region thermodynamics necessary to
correctly ascertain CME propagation speeds, etc.


title:
Extragalactic Point Source Search in Five-year WMAP 41, 61 and 94 GHz
  Maps

abstract:
  We present the results of an extragalactic point source search using the
five-year WMAP 41, 61 and 94 GHz (Q-, V- and W-band) temperature maps. This
work is an extension of our point source search in the WMAP maps applying a
CMB-free technique. An internal linear combination (ILC) map has been formed
from the three-band maps, with the weights chosen to remove the CMB anisotropy
signal as well as to favor a selection of flat-spectrum sources. We find 381
sources at the > 5 sigma level outside the WMAP point source detection mask in
the ILC map, among which 89 are "new" (i.e., not present in the WMAP catalog).
Source fluxes have been calculated and corrected for the Eddington bias. We
have solidly identified 367 (96.3%) of our sources. The 1 sigma positional
uncertainty is estimated to be 2'. The 14 unidentified sources could be either
extended radio structure or obscured by Galactic emission. We have also applied
the same detection process on simulated maps and found 364+/-21 detections on
average. The recovered source distribution N(>S) agrees well with the
simulation input, which proves the reliability of this method.


title: To mechanics of deformation, flow, and fracture

abstract:
  It is stated in the main in essence new approach to mechanics of the stressed
state of the solid body from statistically isotropic material and the
homogeneous liquid dynamics. The approach essence is in the detected property
of the core-shell spontaneous structurization of internal energy of the solid
and liquid bodies in its natural state and under action of external forces. The
method elements of construction of physically adequate model of the stressed
state of the solid and liquid bodies, reproduced exactly its behavior on the
stages of elastic and plastic deformation, flow and fracture, are stated. It is
adduced a number of the examples of the stressed state construction of the
simple form bodies under action of its tension, compression, torsion and at its
contact interaction. For the first time it is adduced structure of the
principal - normal - stresses in cylindrical bar under action of the torsion
moment. The detected property and the developed method is one of necessary
bases for construction of physically adequate mathematical model of the
stressed state of the body and fluid in contrast to traditional approach.


title:
A Search for $B^+ \to \ell^+ \nu_{\ell}$ Recoiling Against $B^{-}\to
  D^{0} \ell^{-}\bar{\nu} X$

abstract:
  We present a search for the decay $\B^+ \to \ell^+ \nu_{\ell} (\ell = \tau,
\mu, \mathrm{or} e)$ in $(458.9 \pm 5.1) \times 10^{6}$ $\Upsilon(4S)$ decays
recorded with the Babar detector at the SLAC PEP-II $B$-Factory. A sample of
events with one reconstructed exclusive semi-leptonic B decay ($B^{-}\to D^{0}
\ell^{-}\bar{\nu} X$) is selected, and in the recoil a search for $\B^+ \to
\ell^+ \nu_{\ell}$ signal is performed. The $\tau$ is identified in the
following channels: $\tau^+ \to e^+ \nu_e \overline{\nu}_\tau$, $\tau^+ \to
\mu^+ \nu_{\mu} \overline{\nu}_{\tau}$, $\tau^+ \to \pi^+
\overline{\nu}_{\tau}$, and $\tau^+ \to \pi^+ \pi^{0} \overline{\nu}_{\tau}$.
The analysis strategy and the statistical procedure is set up for the branching
fraction extraction or upper limit determination. We determine from the dataset
a preliminary measurement of $\mathcal{B}(\B^+ \to \tau^+ \nu_{\tau}) = (1.8
\pm 0.8 \pm 0.1) \times 10^{-4}$, which excludes zero at $2.4 \sigma$, and
$f_{B} = 230 \pm 57 \mev $. Combination with the hadronically tagged
measurement yields $\mathcal{B}(\B^+ \to \tau^+ \nu_{\tau}) = (1.8 \pm 0.6)
\times 10^{-4}$. We also set preliminary limits on the branching fractions at
$\mathcal{B}(\B^+ \to e^+ \nu_{e}) < 7.7 \times 10^{-6} (\textrm{90% C.L.})$,
$\mathcal{B}(\B^+ \to \mu^+ \nu_{\mu}) < 11 \times 10^{-6} (\textrm{90%
C.L.})$, and $\mathcal{B}(\B^+ \to \tau^+ \nu_{\tau}) < 3.2 \times 10^{-4}
(\textrm{90% C.L.})$.


title: Vesicles in a Poiseuille flow

abstract:
  Vesicle dynamics in unbounded Poiseuille flow is analyzed using a
small-deformation theory. Our analytical results quantitatively describe
vesicle migration and provide new physical insights. At low ratio between the
inner and outer viscosity $\lambda$ (i.e. in the tank-treading regime), the
vesicle always migrates towards the flow centerline, unlike other soft
particles such as drops. Above a critical $\lambda$, vesicle tumbles and
cross-stream migration vanishes. A novel feature is predicted, namely the
coexistence of two types of nonequilibrium configurations at the centreline, a
bullet-like and a parachute-like shapes.


title: The Advanced X-ray Timing Array (AXTAR)

abstract:
  AXTAR is an X-ray observatory mission concept, currently under study in the
U.S., that combines very large collecting area, broadband spectral coverage,
high time resolution, highly flexible scheduling, and an ability to respond
promptly to time-critical targets of opportunity. It is optimized for
submillisecond timing of bright Galactic X-ray sources in order to study
phenomena at the natural time scales of neutron star surfaces and black hole
event horizons, thus probing the physics of ultradense matter, strongly curved
spacetimes, and intense magnetic fields. AXTAR's main instrument is a
collimated, thick Si pixel detector with 2-50 keV coverage and 8 square meters
collecting area. For timing observations of accreting neutron stars and black
holes, AXTAR provides at least an order of magnitude improvement in sensitivity
over both RXTE and Constellation-X. AXTAR also carries a sensitive sky monitor
that acts as a trigger for pointed observations of X-ray transients and also
provides continuous monitoring of the X-ray sky with 20 times the sensitivity
of the RXTE ASM. AXTAR builds on detector and electronics technology previously
developed for other applications and thus combines high technical readiness and
well understood cost.


title:
Inverse theorems in the theory of approximation of vectors in a Banach
  space with exponential type entire vectors

abstract:
  Arbitrary operator A on a Banach space X which is the generator of C_0-group
with certain growth condition at infinity is considered. The relationship
between its exponential type entire vectors and its spectral subspaces is
found. Inverse theorems on connection between the degree of smoothness of
vector $x\in X$ with respect to operator A, the rate of convergence to zero of
the best approximation of x by exponential type entire vectors for operator A,
and the k-module of continuity are established. Also, a generalization of the
Bernstein-type inequality is obtained. The results allow to obtain
Bernstein-type inequalities in weighted L_p spaces.


title: The Spin Distribution of Millisecond X-ray Pulsars

abstract:
  The spin frequency distribution of accreting millisecond X-ray pulsars cuts
off sharply above 730 Hz, well below the breakup spin rate for most neutron
star equations of state. I review several different ideas for explaining this
cutoff. There is currently considerable interest in the idea that gravitational
radiation from rapidly rotating pulsars might act to limit spin up by
accretion, possibly allowing eventual direct detection with gravitational wave
interferometers. I describe how long-term X-ray timing of fast accreting
millisecond pulsars like the 599 Hz source IGR J00291+5934 can test the
gravitational wave model for the spin frequency limit.


title: Impact of modulation on CMB B-mode polarization experiments

abstract:
  We investigate the impact of both slow and fast polarization modulation
strategies on the science return of upcoming ground-based experiments aimed at
measuring the B-mode polarization of the CMB. Using simulations of the Clover
experiment, we compare the ability of modulated and un-modulated observations
to recover the signature of gravitational waves in the polarized CMB sky in the
presence of a number of anticipated systematic effects. The general
expectations that fast modulation is helpful in mitigating low-frequency
detector noise, and that the additional redundancy in the projection of the
instrument's polarization sensitivity directions onto the sky when modulating
reduces the impact of instrumental polarization, are borne out by our
simulations. Neither low-frequency polarized atmospheric fluctuations nor
systematic errors in the polarization sensitivity directions are mitigated by
modulation. Additionally, we find no significant reduction in the effect of
pointing errors by modulation. For a Clover-like experiment, pointing jitter
should be negligible but any systematic mis-calibration of the polarization
coordinate reference system results in significant E-B mixing on all angular
scales and will require careful control. We also stress the importance of
combining data from multiple detectors in order to remove the effects of
common-mode systematics (such as 1/f atmospheric noise) on the measured
polarization signal. Finally we compare the performance of our simulated
experiment with the predicted performance from a Fisher analysis. We find good
agreement between the Fisher predictions and the simulations except for the
very largest scales where the power spectrum estimator we have used introduces
additional variance to the B-mode signal recovered from our simulations.


title:
Boundary Terms, Variational Principles and Higher Derivative Modified
  Gravity

abstract:
  We discuss the criteria that must be satisfied by a well-posed variational
principle. We clarify the role of Gibbons-Hawking-York type boundary terms in
the actions of higher derivative models of gravity, such as F(R) gravity, and
argue that the correct boundary terms are the naive ones obtained though the
correspondence with scalar-tensor theory, despite the fact that variations of
normal derivatives of the metric must be fixed on the boundary. We show in the
case of F(R) gravity that these boundary terms reproduce the correct ADM energy
in the hamiltonian formalism, and the correct entropy for black holes in the
semi-classical approximation.


title: Doubled Formalism, Complexification and Topological Sigma-Models

abstract:
  We study a generalization of the Alexandrov-Kontsevich-Schwarz-Zaboronsky
(AKSZ) formulation of the A- and B-models which involves a doubling of
coordinates, and can be understood as a complexification of the Poisson
$\sigma$-model underlying these. In the flat space limit the construction
contains models obtained by twisting an N=2 supersymmetric $\sigma$-model on
Hull's doubled geometry. The curved space generalization involves a product of
two diffeomorphic Calabi-Yau manifolds, and the $O(d,d)$ metric can be
understood as a complexification of the CY metric. In addition, we consider
solutions that can not be obtained by twisting the above $\sigma$-model. For
these it is possible to interpolate between a model evaluated on holomorphic
maps and one evaluated on constant maps by different choices of gauge fixing
fermion. Finally, we discuss some intriguing similarities between aspects of
the doubled formulation and topological M-theory, and a possible relation with
results from the theory of Lie and Courant algebroids, where a doubled
formulation plays a role in relating two- and three-dimensional topological
theories.


title:
Hierarchical mean-field approach to the $J_1$-$J_2$ Heisenberg model on
  a square lattice

abstract:
  We study the quantum phase diagram and excitation spectrum of the frustrated
$J_1$-$J_2$ spin-1/2 Heisenberg Hamiltonian. A hierarchical mean-field
approach, at the heart of which lies the idea of identifying {\it relevant}
degrees of freedom, is developed. Thus, by performing educated, manifestly
symmetry preserving mean-field approximations, we unveil fundamental properties
of the system. We then compare various coverings of the square lattice with
plaquettes, dimers and other degrees of freedom, and show that only the {\it
symmetric plaquette} covering, which reproduces the original Bravais lattice,
leads to the known phase diagram. The intermediate quantum paramagnetic phase
is shown to be a (singlet) {\it plaquette crystal}, connected with the
neighboring N\'eel phase by a continuous phase transition. We also introduce
fluctuations around the hierarchical mean-field solutions, and demonstrate that
in the paramagnetic phase the ground and first excited states are separated by
a finite gap, which closes in the N\'eel and columnar phases. Our results
suggest that the quantum phase transition between N\'eel and paramagnetic
phases can be properly described within the Ginzburg-Landau-Wilson paradigm.


title: A Lefschetz hyperplane theorem for Mori dream spaces

abstract:
  Let X be a smooth Mori dream space of dimension at least 4. We show that, if
X satisfies a suitable GIT condition which we call "small unstable locus", then
every smooth ample divisor Y of X is also a Mori dream space. Moreover, the
restriction map identifies the Neron-Severi spaces of X and Y, and under this
identification every Mori chamber of Y is a union of some Mori chambers of X,
and the nef cone of Y is the same as the nef cone of X. This Lefschetz-type
theorem enables one to construct many examples of Mori dream spaces by taking
"Mori dream hypersurfaces" of an ambient Mori dream space, provided that it
satisfies the GIT condition. To facilitate this, we then show that the GIT
condition is stable under taking products and taking the projective bundle of
the direct sum of at least three line bundles, and in the case when X is toric,
we show that the condition is equivalent to the fan of X being 2-neighborly.


title: Nuclear Halos and Drip Lines in Symmetry-Conserving Continuum HFB Theory

abstract:
  We review the properties of nuclear halos and nuclear skins in drip line
nuclei in the framework of the spherical Hartree-Fock-Bogoliubov theory with
continuum effects and projection on good particle number with the Gogny force.
We first establish the position of the un-projected HFB drip lines for the two
most employed parametrizations of the Gogny force and show that the use of
finite-range interactions leads almost always to small-sized halos, even in the
least bound nuclei, which is in agreement with most mean-field predictions. We
also discuss the size of the neutron skin at the drip line and its relation to
neutron asymmetry. The impact of particle-number projection and its conceptual
consequences near the drip line are analyzed in detail. In particular, we
discuss the role of the chemical potential in a projected theory and the
criteria required to define the drip line. We show that including particle
number projection can shift the latter, in particular near closed shells. We
notice that, as a result, the size of the halo can be increased due to larger
pairing correlations. However, combining the most realistic pairing
interaction, a proper treatment of the continuum and particle number projection
does not permit to reproduce the very large halos observed in very light
nuclei.


title:
Quantum spinning strings in AdS_4 x CP^3: testing the Bethe Ansatz
  proposal

abstract:
  Recently, an asymptotic Bethe Ansatz that is claimed to describe anomalous
dimensions of "long" operators in the planar N=6 supersymmetric
three-dimensional Chern-Simons-matter theory dual to quantum superstrings in
AdS_4 x CP^3 was proposed. It initially passed a few consistency checks but
subsequent direct comparison to one-loop string-theory computations created
some controversy. Here we suggest a resolution by pointing out that, contrary
to the initial assumption based on the algebraic curve considerations, the
central interpolating function h(\lambda) entering the BMN or magnon dispersion
relation receives a non-zero one-loop correction in the natural string-theory
computational scheme. We consider a basic example which has already played a
key role in the AdS_5 x S^5 case: a rigid circular string stretched in both
AdS_4 and along an S^1 of CP^3 and carrying two spins. Computing the leading
one-loop quantum correction to its energy allows us to fix the constant
one-loop term in h(\lambda) and also to suggest how one may establish a
correspondence with the Bethe Ansatz proposal, including the non-trivial
one-loop phase factor. We discuss some problems which remain in trying to match
a part of world-sheet contributions (sensitive to compactness of the string
direction) and their Bethe Ansatz counterparts.


title:
Differential Calculus and Integration of Generalized Functions over
  Membranes

abstract:
  In this paper we continue the development of the differential calculus
started by Aragona-Ferandez-Juriaans. Guided by the topology introduced
recently by those authors we introduce the notion of membranes and extend the
definition of integrals given in [2] to integrals defined on membranes. We use
this to prove a generalized version of teh Cauchy formula and to obtain the
Goursat Theorem for generalized holomorphic functions. We also show that the
generalized transport equation can be solved giving an explicit solution


title: Completion of the Proof of the Geometrization Conjecture

abstract:
  This article is a sequel to the book `Ricci Flow and the Poincare Conjecture'
by the same authors. Using the main results of that book we establish the
Geometrization Conjecture for all compact, orientable three-manifolds following
the approach indicated by Perelman in his preprints on the subject. This
approach is to study the collapsed part of the manifold as time goes to
infinity in a Ricci flow with surgery. The main technique for this study is the
theory of Alexandrov spaces. This theory gives local models for the collapsed
part of the manifold. These local models can be glued together to prove that
the collapsed part of the manifold is a graph manifold with incompressible
boundary. From this and previous results, geometrization follows easily.


title:
Consistently Large Cosmic Flows on Scales of 100 Mpc/h: a Challenge for
  the Standard LCDM Cosmology

abstract:
  Peculiar velocity surveys have non-uniform spatial distributions of tracers,
so that the bulk flow estimated from them does not correspond to that of a
simple volume such as a sphere. Thus bulk flow estimates are generally not
strictly comparable between surveys, even those whose effective depths are
similar. In addition, the sparseness of typical surveys can lead to aliasing of
small scale power into what is meant to be a probe of the largest scales. Here
we introduce a new method of calculating bulk flow moments where velocities are
weighted to give an optimal estimate of the bulk flow of an idealized survey,
with the variance of the difference between the estimate and the actual flow
being minimized. These "minimum variance" estimates can be designed to estimate
the bulk flow on a particular scale with minimal sensitivity to small scale
power, and are comparable between surveys. We compile all major peculiar
velocity surveys and apply this new method to them. We find that most surveys
we studied are highly consistent with each other. Taken together the data
suggest that the bulk flow within a Gaussian window of radius 50 Mpc/h is 407
km/s toward l=287 and b=8. The large-scale bulk motion is consistent with
predictions from the local density field. This indicates that there are
significant density fluctuations on very large scales. A flow of this amplitude
on such a large scale is not expected in the WMAP5-normalized LCDM cosmology,
for which the predicted one-dimensional r.m.s. velocity is ~110 km/s. The large
amplitude of the observed bulk flow favors the upper values of the WMAP5
error-ellipse, but even the point at the top of the WMAP5 95% confidence
ellipse predicts a bulk flow which is too low compared to that observed at >98%
confidence level.


title: ESA White paper: Atmospheric modeling: Setting Biomarkers in context

abstract:
  Motivation: ESAs goal to detect biomarkers in Earth-like exoplanets in the
Habitable Zone requires theoretical groundwork that needs to be done to model
the influence of different parameters on the detectable biomarkers.
  We need to model a wide parameter space (chemical composition, pressure,
evolution, interior structure and outgassing, clouds) to generate a grid of
models that inform our detection strategy as well as can help characterize the
spectra of the small rocky planets detected.


title: Very fast optical flaring from a possible new Galactic magnetar

abstract:
  Highly luminous rapid flares are characteristic of processes around compact
objects like white dwarfs, neutron stars or black holes. In the high energy
regime of X- and gamma-rays, outbursts with variability time-scales of seconds
and faster are routinely observed, e.g. in gamma-ray bursts or Soft Gamma
Repeaters. In the optical, flaring activity on such time-scales has never been
observed outside the prompt phase of GRBs. This is mostly due to the fact that
outbursts with strong, fast flaring usually are discovered in the high-energy
regime. Most optical follow-up observations of such transients employ
instruments with integration times exceeding tens of seconds, which are
therefore unable to resolve fast variability. Here we show the observation of
extremely bright and rapid optical flaring in the galactic transient SWIFT
J195509.6+261406. Flaring of this kind has never previously been reported. Our
optical light-curves are phenomenologically similar to high energy light-curves
of Soft Gamma Repeaters and Anomalous X-ray Pulsars, which are thought to be
neutron stars with extremely high magnetic fields (magnetars). This suggests
similar emission processes may be at work, but in contrast to the other known
magnetars with strong emission in the optical.


title: On the regularity of maximal operators

abstract:
  We study the regularity of the bilinear maximal operator when applied to
Sobolev functions, proving that it maps $W^{1,p}(\mathbb{R}) \times
W^{1,q}(\mathbb{R}) \to W^{1,r}(\mathbb{R})$ with $1 <p,q < \infty$ and $r\geq
1$, boundedly and continuously. The same result holds on $\mathbb{R}^n$ when
$r>1$. We also investigate the almost everywhere and weak convergence under the
action of the classical Hardy-Littlewood maximal operator, both in its global
and local versions.


title: Nonlinear properties of split-ring resonators

abstract:
  In this letter, the properties of split-ring resonators (SRRs) loaded with
high-Q capacitors and nonlinear varactors are theoretically analyzed and
experimentally measured. We demonstrate that the resonance frequency $f_m$ of
the nonlinear SRRs can be tuned by increasing the incident power. $f_m$ moves
to lower and higher frequencies for the SRR loaded with one varactor and two
back-to-back varactors, respectively. For high incident powers, we observe
bistable tunable metamaterials and hysteresis effects. Moreover, the coupling
between two nonlinear SRRs is also discussed.


title:
Self-consistent analysis of electron-phonon coupling parameters of
  graphene

abstract:
  We present a self-consistent analysis of the photoemission spectral function
A(k, w) of graphene monolayers grown epitaxially on SiC(0001). New information
derived from spectral intensity anomalies (in addition to linewidths and peak
positions) confirms that sizeable kinks in the electronic dispersion at the
Dirac energy ED and near the Fermi level EF arise from many-body interactions,
not single-particle effects such as substrate bonding or extra bands. The
relative electron-phonon scattering rate from phonons at different energy
scales evolves with doping. The electron-phonon coupling strength is extracted
and found to be much larger (~3.5-5 times) than predicted.


title: Improved Sequential Stopping Rule for Monte Carlo Simulation

abstract:
  This paper presents an improved result on the negative-binomial Monte Carlo
technique analyzed in a previous paper for the estimation of an unknown
probability p. Specifically, the confidence level associated to a relative
interval [p/\mu_2, p\mu_1], with \mu_1, \mu_2 > 1, is proved to exceed its
asymptotic value for a broader range of intervals than that given in the
referred paper, and for any value of p. This extends the applicability of the
estimator, relaxing the conditions that guarantee a given confidence level.


title: Chimera states in heterogeneous networks

abstract:
  Chimera states in networks of coupled oscillators occur when some fraction of
the oscillators synchronise with one another, while the remaining oscillators
are incoherent. Several groups have studied chimerae in networks of identical
oscillators, but here we study these states in a heterogeneous model for which
the natural frequencies of the oscillators are chosen from a distribution. We
obtain exact results by reduction to a finite set of differential equations. We
find that heterogeneity can destroy chimerae, destroy all states except
chimerae, or destabilise chimerae in Hopf bifurcations, depending on the form
of the heterogeneity.


title:
Sharp approximations to the Bernoulli periodic functions by
  trigonometric polynomials

abstract:
  We obtain optimal trigonometric polynomials of a given degree $N$ that
majorize, minorize and approximate in $L^1(\mathbb{R}/\mathbb{Z})$ the
Bernoulli periodic functions. These are the periodic analogues of two works of
F. Littmann that generalize a paper of J. Vaaler. As applications we provide
the corresponding Erd\"{o}s-Tur\'{a}n-type inequalities, approximations to
other periodic functions and bounds for certain Hermitian forms.


title: Some extremal functions in Fourier analysis, II

abstract:
  We obtain extremal majorants and minorants of exponential type for a class of
even functions on $\R$ which includes $\log |x|$ and $|x|^\alpha$, where $-1 <
\alpha < 1$. We also give periodic versions of these results in which the
majorants and minorants are trigonometric polynomials of bounded degree. As
applications we obtain optimal estimates for certain Hermitian forms, which
include discrete analogues of the one dimensional Hardy-Littlewood-Sobolev
inequalities. A further application provides an Erd\"{o}s-Tur\'{a}n-type
inequality that estimates the sup norm of algebraic polynomials on the unit
disc in terms of power sums in the roots of the polynomials.


title:
Universality in the vibrational spectra of weakly-disordered
  two-dimensional clusters

abstract:
  We numerically investigate the vibrational spectra of single-component
clusters in two-dimensions. Stable configurations of clusters at local energy
minima are obtained, and for each the hessian matrix is evaluated and
diagonalized to obtain eigenvalues as well as eigenvectors. We study the
density of states so obtained as a function of the width of the potential well
describing the two-body interaction. As the width is reduced, as in three
dimensions, we find that the density of states approaches a common form, but
the two-peak behavior survives. Further, calculations of the participation
ratio show that most states are extended, although a smaller fraction of the
degrees of freedom are involved in these modes, compared to three dimensions.
We show that the fluctuation properties of these modes converges to those of
the Gaussian orthogonal ensemble of random matrices, in common with previous
results on three dimensional amorphous clusters and molecular liquids


title:
Constraining Cosmology with High Convergence Regions in Weak Lensing
  Surveys

abstract:
  We propose to use a simple observable, the fractional area of "hot spots" in
weak gravitational lensing mass maps which are detected with high significance,
to determine background cosmological parameters. Because these high-convergence
regions are directly related to the physical nonlinear structures of the
universe, they derive cosmological information mainly from the nonlinear regime
of density fluctuations. We show that in combination with future cosmic
microwave background anisotropy measurements, this method can place constraints
on cosmological parameters that are comparable to those from the redshift
distribution of galaxy cluster abundances. The main advantage of the statistic
proposed in this paper is that projection effects, normally the main source of
uncertainty when determining the presence and the mass of a galaxy cluster,
here serve as a source of information.


title: Some extremal functions in Fourier analysis, III

abstract:
  We obtain the best approximation in $L^1(\R)$, by entire functions of
exponential type, for a class of even functions that includes
$e^{-\lambda|x|}$, where $\lambda >0$, $\log |x|$ and $|x|^{\alpha}$, where $-1
< \alpha < 1$. We also give periodic versions of these results where the
approximating functions are trigonometric polynomials of bounded degree.


title: A sharp inequality for the Strichartz norm

abstract:
  Let $u:\R \times \R^n \to \C$ be the solution of the linear Schr\"odinger
equation $iu_t + \Delta u =0$ with initial data $u(0,x) = f(x)$. In the first
part of this paper we obtain a sharp inequality for the Strichartz norm
$\|u(t,x)\|_{L^{2k}_tL^{2k}_x(\R \times\R^n)}$, where $k\in \Z$, $k \geq 2$ and
$(n,k) \neq (1,2)$, that admits only Gaussian maximizers. As corollaries we
obtain sharp forms of the classical Strichartz inequalities in low dimensions
(works of Foschi and Hundertmark - Zharnitsky) and also sharp forms of some
Sobolev-Strichartz inequalities. In the second part of the paper we express
Foschi's sharp inequalities for the Schr\"odinger and wave equations in the
broader setting of sharp restriction/extension estimates for the paraboloid and
the cone.


title: Deformations of glued G_2-manifolds

abstract:
  We study how a gluing construction, which produces compact manifolds with
holonomy G_2 from matching pairs of asymptotically cylindrical G_2-manifolds,
behaves under deformations. We show that the gluing construction defines a
smooth map from a moduli space of gluing data to the moduli space of
torsion-free G_2-structures on the glued manifold, and that this is a local
diffeomorphism. We use this to partially compactify the moduli space of
torsion-free G_2-structures, including it as the interior of a topological
manifold with boundary. The boundary points are equivalence classes of matching
pairs of torsion-free asymptotically cylindrical G_2-structures.


title:
Electron-phonon bound states and impurity band formation in quantum
  wells

abstract:
  A generalized propagation matrix method is used to study how scattering off
local Einstein phonons affects resonant electron transmission through quantum
wells. In particular, the parity and the number of the phonon mediated
satellite resonances are found to depend on the available scattering channels.
For a large number of phonon channels, the formation of low-energy impurity
bands is observed. Furthermore, an effective theory is developed which
accurately describes the phonon generated sidebands for sufficiently small
electron-phonon coupling. Finally, the current-voltage characteristics caused
by phonon assisted transmission satellites are discussed for a specific double
barrier geometry.


title: Foliations for Quasi-Fuchsian 3-Manifolds

abstract:
  In this paper, we prove that if a quasi-Fuchsian 3-manifold contains a
minimal surface whose principle curvature is less than 1, then it admits a
foliation such that each leaf is a surface of constant mean curvature. The key
method that we use here is volume preserving mean curvature flow.


title: Target Localization Accuracy Gain in MIMO Radar Based Systems

abstract:
  This paper presents an analysis of target localization accuracy, attainable
by the use of MIMO (Multiple-Input Multiple-Output) radar systems, configured
with multiple transmit and receive sensors, widely distributed over a given
area. The Cramer-Rao lower bound (CRLB) for target localization accuracy is
developed for both coherent and non-coherent processing. Coherent processing
requires a common phase reference for all transmit and receive sensors. The
CRLB is shown to be inversely proportional to the signal effective bandwidth in
the non-coherent case, but is approximately inversely proportional to the
carrier frequency in the coherent case. We further prove that optimization over
the sensors' positions lowers the CRLB by a factor equal to the product of the
number of transmitting and receiving sensors. The best linear unbiased
estimator (BLUE) is derived for the MIMO target localization problem. The
BLUE's utility is in providing a closed form localization estimate that
facilitates the analysis of the relations between sensors locations, target
location, and localization accuracy. Geometric dilution of precision (GDOP)
contours are used to map the relative performance accuracy for a given layout
of radars over a given geographic area.


title: Information transmission in oscillatory neural activity

abstract:
  Periodic neural activity not locked to the stimulus or to motor responses is
usually ignored. Here, we present new tools for modeling and quantifying the
information transmission based on periodic neural activity that occurs with
quasi-random phase relative to the stimulus. We propose a model to reproduce
characteristic features of oscillatory spike trains, such as histograms of
inter-spike intervals and phase locking of spikes to an oscillatory influence.
The proposed model is based on an inhomogeneous Gamma process governed by a
density function that is a product of the usual stimulus-dependent rate and a
quasi-periodic function. Further, we present an analysis method generalizing
the direct method (Rieke et al, 1999; Brenner et al, 2000) to assess the
information content in such data. We demonstrate these tools on recordings from
relay cells in the lateral geniculate nucleus of the cat.


title: Convex Trace Functions on Quantum Channels and the Additivity Conjecture

abstract:
  We study a natural generalization of the additivity problem in quantum
information theory: given a pair of quantum channels, then what is the set of
convex trace functions that attain their maximum on unentangled inputs, if they
are applied to the corresponding output state?
  We prove several results on the structure of the set of those convex
functions that are "additive" in this more general sense. In particular, we
show that all operator convex functions are additive for the Werner-Holevo
channel in 3x3 dimensions, which contains the well-known additivity results for
this channel as special cases.


title:
Torsion points of abelian varieties with values in infinite extensions
  over a p-adic field

abstract:
  Let $A$ be an abelian variety over a $p$-adic field $K$ and $L$ an algebraic
infinite extension over $K$. We consider the finiteness of the torsion part of
the group of rational points $A(L)$ under some assumptions. In 1975, Hideo Imai
proved that such a group is finite if $A$ has good reduction and $L$ is the
cyclotomic $\mathbb{Z}_p$-extension of $K$. In this talk, first we show a
generalization of Imai's result in the case where $A$ has ordinary good
reduction. Next we give some finiteness results when $A$ is an elliptic curve
and $L$ is the field generated by the $p$-power torsion of an elliptic curve.


title: The muon g-2 discrepancy: errors or new physics?

abstract:
  After a brief review of the muon g-2 status, we discuss hypothetical errors
in the Standard Model prediction that could explain the present discrepancy
with the experimental value. None of them looks likely. In particular, an
hypothetical increase of the hadroproduction cross section in low-energy e^+e^-
collisions could bridge the muon g-2 discrepancy, but is shown to be unlikely
in view of current experimental error estimates. If, nonetheless, this turns
out to be the explanation of the discrepancy, then the 95% CL upper bound on
the Higgs boson mass is reduced to about 130 GeV which, in conjunction with the
experimental 114.4 GeV 95% CL lower bound, leaves a narrow window for the mass
of this fundamental particle.


title: Quantum super-cavity with atomic mirrors

abstract:
  We study single-photon transport in an array of coupled microcavities where
two two-level atomic systems are embedded in two separate cavities of the
array. We find that a single-photon can be totally reflected by a single
two-level system. However, two separate two-level systems can also create,
between them, single-photon quasi-bound states. Therefore, a single two-level
system in the cavity array can act as a mirror while a different type of cavity
can be formed by using two two-level systems, acting as tunable "mirrors",
inside two separate cavities in the array. In analogy with superlattices in
solid state, we call this new "cavity inside a coupled-cavity array" a
super-cavity. This supercavity is the quantum analog of Fabry-Perot
interferometers. Moreover, we show that the physical properties of this quantum
super-cavity can be adjusted by changing the frequencies of these two-level
systems.


title:
Shape transformation transitions in a model of fixed-connectivity
  surfaces supported by skeletons

abstract:
  A compartmentalized surface model of Nambu and Goto is studied on
triangulated spherical surfaces by using the canonical Monte Carlo simulation
technique. One-dimensional bending energy is defined on the skeletons and at
the junctions, and the mechanical strength of the surface is supplied by the
one-dimensional bending energy defined on the skeletons and junctions. The
compartment size is characterized by the total number L^\prime of bonds between
the two-neighboring junctions and is assumed to have values in the range from
L^\prime=2 to L^\prime=8 in the simulations, while that of the previously
reported model is characterized by L^\prime=1, where all vertices of the
triangulated surface are the junctions. Therefore, the model in this paper is
considered to be an extension of the previous model in the sense that the
previous model is obtained from the model in this paper in the limit of
L^\prime\to1 The model in this paper is identical to the Nambu-Goto surface
model without curvature energies in the limit of L^\prime\to \infty and hence
is expected to be ill-defined at sufficiently large L^\prime. One remarkable
result obtained in this paper is that the model has a well-defined smooth phase
even at relatively large L^\prime just as the previous model of L^\prime\to1.
It is also remarkable that the fluctuations of surface in the smooth phase are
crucially dependent on L^\prime; we can see no surface fluctuation when
L^\prime\leq2, while relatively large fluctuations are seen when L^\prime\geq3.


title:
Higgs funnel region of SUSY dark matter for small $\tan\beta$ and
  renormalization group effects on pseudoscalar Higgs boson with scalar mass
  non-universality

abstract:
  A non-universal scalar mass supergravity type of model is explored where the
first two generation of scalars and the third generation of sleptons may be
very massive. Lighter or vanishing third generation of squarks as well as Higgs
scalars at the unification scale cause the radiative electroweak symmetry
breaking constraint to be less prohibitive. Thus, both FCNC/CP-violation
problems as well as the naturalness problem are within control. We identify a
large slepton mass effect in the RGE of $m_{H_D}^2$ (for the down type of
Higgs) that may turn the later negative at the electroweak scale even for a
small $\tan\beta$. A hyperbolic branch/focus point like effect is found for
$m_A^2$ that may result in very light Higgs spectra. The lightest stable
particle is dominantly a bino that pair annihilates via Higgs exchange, giving
rise to a WMAP satisfied relic density region for all $\tan\beta$. Detection
prospects of such LSPs in the upcoming dark matter experiments both of direct
and indirect types (photon flux) are interesting. The Higgs bosons and the
third generation of squarks are light in this scenario and these may be easily
probed besides charginos and neutralinos in the early runs of LHC.


title:
Theoretical Limits on Errors and Acquisition Rates in Localizing
  Switchable Fluorophores

abstract:
  A variety of recent imaging techniques are able to beat the diffraction limit
in fluorescence microcopy by activating and localizing subsets of the
fluorescent molecules in the specimen, and repeating this process until all of
the molecules have been imaged. In these techniques there is a tradeoff between
speed (activating more molecules per imaging cycle) and error rates (activating
more molecules risks producing overlapping images that hide information on
molecular positions), and so intelligent image-processing approaches are needed
to identify and reject overlapping images. We introduce here a formalism for
defining error rates, derive a general relationship between error rates, image
acquisition rates, and the performance characteristics of the image processing
algorithms, and show that there is a minimum acquisition time irrespective of
algorithm performance. We also consider algorithms that can infer molecular
positions from images of overlapping blurs, and derive the dependence of the
minimimum acquisition time on algorithm performance.


title: On a Cuntz-Krieger functor

abstract:
  We construct a covariant functor from the topological torus bundles to the
so-called Cuntz-Krieger algebras; the functor maps homeomorphic bundles into
the stably isomorphic Cuntz-Krieger algebras. It is shown, that the K-theory of
the Cuntz-Krieger algebra encodes torsion of the first homology group of the
bundle. We illustrate the result by examples.


title:
First order phase transition in the anisotropic quantum orbital compass
  model

abstract:
  We investigate the anisotropic quantum orbital compass model on an infinite
square lattice by means of the infinite projected entangled-pair state
algorithm. For varying values of the $J_x$ and $J_z$ coupling constants of the
model, we approximate the ground state and evaluate quantities such as its
expected energy and local order parameters. We also compute adiabatic time
evolutions of the ground state, and show that several ground states with
different local properties coexist at $J_x = J_z$. All our calculations are
fully consistent with a first order quantum phase transition at this point,
thus corroborating previous numerical evidence. Our results also suggest that
tensor network algorithms are particularly fitted to characterize first order
quantum phase transitions.


title: Entropic Geometry of Crowd Dynamics

abstract:
  We propose an entropic geometrical model of psycho-physical crowd dynamics
(with dissipative crowd kinematics), using Feynman action-amplitude formalism
that operates on three synergetic levels: macro, meso and micro. The intent is
to explain the dynamics of crowds simultaneously and consistently across these
three levels, in order to characterize their geometrical properties
particularly with respect to behavior regimes and the state changes between
them. Its most natural statistical descriptor is crowd entropy $S$ that
satisfies the Prigogine's extended second law of thermodynamics,
$\partial_tS\geq 0$ (for any nonisolated multi-component system). Qualitative
similarities and superpositions between individual and crowd configuration
manifolds motivate our claim that goal-directed crowd movement operates under
entropy conservation, $\partial_tS = 0$, while natural crowd dynamics operates
under (monotonically) increasing entropy function, $\partial_tS > 0$. Between
these two distinct topological phases lies a phase transition with a chaotic
inter-phase. Both inertial crowd dynamics and its dissipative kinematics
represent diffusion processes on the crowd manifold governed by the Ricci flow,
with the associated Perelman entropy-action.
  Keywords: Crowd psycho-physical dynamics, action-amplitude formalism, crowd
manifold, Ricci flow, Perelman entropy, topological phase transition


abstract:
  We introduce the notion of Hamiltonian spaces for Manin pairs over manifolds,
using the so-called generalized Dirac structures. As an example, we describe
Hamiltonian spaces of a quasi-Lie bialgebroid using this general framework. We
also discuss reduction of Hamiltonian spaces of this general type.


title: Exactness of the replica method in perturbation

abstract:
  The replica method for a quenched disordered system is considered in a
perturbative field theory. Since correction in a finite-order perturbation is
given in a polynomial of the replica number $n$, the zero-replica limit $n \to
0$ is regarded as extracting the constant term from the polynomial, which
mathematically makes sense. The meaning of the extraction is clarified
comparing with a direct calculation.


title:
Isospin-projected nuclear level densities by the shell model Monte Carlo
  method

abstract:
  We have developed an efficient isospin projection method in the shell model
Monte Carlo approach for isospin-conserving Hamiltonians. For isoscalar
observables this projection method has the advantage of being exact sample by
sample. The isospin projection method allows us to take into account the proper
isospin dependence of the nuclear interaction, thus avoiding a sign problem
that such an interaction introduces in unprojected calculations. We apply our
method in the calculation of the isospin dependence of level densities in the
complete $pf+g_{9/2}$ shell. We find that isospin-dependent corrections to the
total level density are particularly important for $N \sim Z$ nuclei.


title: Knots and Links in Physical Systems

abstract:
  Few physical systems with topologies more complicated than simple gaussian
linking have been explored in detail. Here we focus on examples with higher
topologies in non-relativistic quantum mechanics and in QCD.


title: Dynamic critical phenomena in the AdS/CFT duality

abstract:
  In critical phenomena, singular behaviors arise not only for thermodynamic
quantities but also for transport coefficients. We study this dynamic critical
phenomenon in the AdS/CFT duality. We consider black holes with a single
R-charge in various dimensions and compute the R-charge diffusion in the linear
perturbations. In this case, the black holes belong to model B according to the
classification of Hohenberg and Halperin.


title: Large Extra Dimensions and Holography

abstract:
  The holographic principle asserts that the entropy of a system cannot exceed
its boundary area in Planck units. However, conventional quantum field theory
fails to describe such systems. In this Letter, we assume the existence of
large $n$ extra dimensions and propose a relationship between UV and IR cutoffs
in this case. We find that if $n=2$, this effective field theory could be a
good description of holographic systems. If these extra dimensions are detected
in future experiments, it will help to prove the validity of the holographic
principle. We also discuss implications for the cosmological constant problem.


title: Thick de Sitter brane solutions in higher dimensions

abstract:
  We present thick de Sitter brane solutions which are supported by two
interacting {\it phantom} scalar fields in five-, six- and seven-dimensional
spacetime. It is shown that for all cases regular solutions with anti-de Sitter
asymptotic (5D problem) and a flat asymptotic far from the brane (6D and 7D
cases) exist. We also discuss the stability of our solutions.


title:
Fermi-liquid effects in the gapless state of marginally thin
  superconducting films

abstract:
  We present low temperature tunneling density-of-states measurements in Al
films in high parallel magnetic fields. The thickness range of the films, t=6-9
nm, was chosen so that the orbital and Zeeman contributions to their parallel
critical fields were comparable. In this quasi-spin paramagnetically limited
configuration, the field produces a significant suppression of the gap, and at
high fields the gapless state is reached. By comparing measured and calculated
tunneling spectra we are able to extract the value of the antisymmetric
Fermi-liquid parameter G^0 and thereby deduce the quasiparticle density
dependence of the effective parameter G^0_{eff} across the gapless state.


title: B Physics at the Tevatron

abstract:
  The Fermilab Tevatron offers unique opportunities to perform measurements of
the heavier b-hadrons that are not accessible at the Y(4S) resonance. In this
summary, we describe most important heavy flavor results from DO and CDF
collaborations and we discuss prospects for future measurements, that could
reveal New Physics before the start-up of the Large Hadron Collider (LHC).


title: Sparse image reconstruction for molecular imaging

abstract:
  The application that motivates this paper is molecular imaging at the atomic
level. When discretized at sub-atomic distances, the volume is inherently
sparse. Noiseless measurements from an imaging technology can be modeled by
convolution of the image with the system point spread function (psf). Such is
the case with magnetic resonance force microscopy (MRFM), an emerging
technology where imaging of an individual tobacco mosaic virus was recently
demonstrated with nanometer resolution. We also consider additive white
Gaussian noise (AWGN) in the measurements. Many prior works of sparse
estimators have focused on the case when H has low coherence; however, the
system matrix H in our application is the convolution matrix for the system
psf. A typical convolution matrix has high coherence. The paper therefore does
not assume a low coherence H. A discrete-continuous form of the Laplacian and
atom at zero (LAZE) p.d.f. used by Johnstone and Silverman is formulated, and
two sparse estimators derived by maximizing the joint p.d.f. of the observation
and image conditioned on the hyperparameters. A thresholding rule that
generalizes the hard and soft thresholding rule appears in the course of the
derivation. This so-called hybrid thresholding rule, when used in the iterative
thresholding framework, gives rise to the hybrid estimator, a generalization of
the lasso. Unbiased estimates of the hyperparameters for the lasso and hybrid
estimator are obtained via Stein's unbiased risk estimate (SURE). A numerical
study with a Gaussian psf and two sparse images shows that the hybrid estimator
outperforms the lasso.


title: Predicting Transcription Factor Specificity with All-Atom Models

abstract:
  The binding of a transcription factor (TF) to a DNA operator site can
initiate or repress the expression of a gene. Computational prediction of sites
recognized by a TF has traditionally relied upon knowledge of several cognate
sites, rather than an ab initio approach. Here, we examine the possibility of
using structure-based energy calculations that require no knowledge of bound
sites but rather start with the structure of a protein-DNA complex. We study
the PurR E. coli TF, and explore to which extent atomistic models of
protein-DNA complexes can be used to distinguish between cognate and
non-cognate DNA sites. Particular emphasis is placed on systematic evaluation
of this approach by comparing its performance with bioinformatic methods, by
testing it against random decoys and sites of homologous TFs. We also examine a
set of experimental mutations in both DNA and the protein. Using our explicit
estimates of energy, we show that the specificity for PurR is dominated by
direct protein-DNA interactions, and weakly influenced by bending of DNA.


title: Space of K\"ahler metrics (IV)--On the lower bound of the K-energy

abstract:
  We partially confirm an old conjecture of Donaldson that if there exists a
cscK metrics in a given K\"ahler class, then there is no degenerated geodesic
ray which is tamed by a bounded ambient geometry unless it parallels to a
holomorphic line consists of cscK metrics only. We also prove that for simple
test configuration where the central fibre has a cscK metric, the K energy
functionals in the nearby fibre must also have a uniform lower bound in its
underlying K\"ahler class.


title: Multiprocessor Global Scheduling on Frame-Based DVFS Systems

abstract:
  In this ongoing work, we are interested in multiprocessor energy efficient
systems, where task durations are not known in advance, but are know
stochastically. More precisely, we consider global scheduling algorithms for
frame-based multiprocessor stochastic DVFS (Dynamic Voltage and Frequency
Scaling) systems. Moreover, we consider processors with a discrete set of
available frequencies.


title:
Optically induced electrokinetic patterning and manipulation of
  particles

abstract:
  This fluid dynamics video showcases how optically induced electrokinetic
forces can be used to drive three-dimensional micro-vortices. The strong
microfluidic vortices are used constructively in conjunction with other
electrokinetic forces to dynamically and rapidly aggregate particle groups.
Particle manipulation is achieved on the surface of a parallel-plate
gold/indium tin oxide (ITO) electrode that is illuminated with near-infrared
(1064 nm) optical patterns and biased with a low frequency ($<$ 100 kHz)
alternating current (AC) signal. The fluid dynamics video shows how
electrokinetically driven flows in the microdomain can be used for non-invasive
particle manipulation.


title: Asymptotic Behavior of Multidimensional Scalar Relaxation Shocks

abstract:
  We establish pointwise bounds for the Green function and consequent
linearized stability for multidimensional planar relaxation shocks of general
relaxation systems whose equilibrium model is scalar, under the necessary
assumption of spectral stability. Moreover, we obtain nonlinear $L^{2}$
asymptotic behavior/sharp decay rate of perturbed weak shocks of general
simultaneously symmetrizable relaxation systems, under small $L^{1}\cap
H^{[d/2]+3}$ perturbations with first moment in the normal direction to the
front.


title:
Theoretical Study for Deformation Kinetics of Glassy Solid Helium within
  Cylindrical Microtubes

abstract:
  The deformation kinetics for glassy solid helium confined in microscopic
domain at very low temperature regime was investigated using a transition-rate
model considering the shear thinning behavior which means, once material being
subjected to high shear rates, the viscosity diminishes with increasing shear
rate. The preliminary results show that there might be nearly frictionless
fields for rate of deformation due to the almost vanishing shear stress in
microtubes at very low temperature regime subjected to some surface conditions
: The relatively larger roughness (compared to the macroscopic domain) inside
microtubes and the slip. As the pore size decreases, the surface-to-volume
ratio increases and therefore, surface roughness will greatly affect the
deformation kinetics in microtubes. By using the boundary perturbation method,
we obtained a class of temperature and activation energy dependent fields for
the deformation kinetics at low temperature regime with the presumed small wavy
roughness distributed along the walls of an cylindrical microtube. The critical
deformation kinetics of the glassy matter is dependent upon the temperature,
activation energy, activation volume, orientation dependent and is proportional
to the (referenced) shear rate, the slip length, the amplitude and the
orientation of the wavy-roughness. Finally, we also discuss the quantitative
similarity between our results with Ray and Hallock [Phys. Rev. Lett. {\bf
100}, 235301 (2008)].


title: Learning Hidden Markov Models using Non-Negative Matrix Factorization

abstract:
  The Baum-Welsh algorithm together with its derivatives and variations has
been the main technique for learning Hidden Markov Models (HMM) from
observational data. We present an HMM learning algorithm based on the
non-negative matrix factorization (NMF) of higher order Markovian statistics
that is structurally different from the Baum-Welsh and its associated
approaches. The described algorithm supports estimation of the number of
recurrent states of an HMM and iterates the non-negative matrix factorization
(NMF) algorithm to improve the learned HMM parameters. Numerical examples are
provided as well.


title:
Localization properties of a tight-binding electronic model on the
  Apollonian network

abstract:
  An investigation on the properties of electronic states of a tight-binding
Hamiltonian on the Apollonian network is presented. This structure, which is
defined based on the Apollonian packing problem, has been explored both as a
complex network, and as a substrate, on the top of which physical models can
defined. The Schrodinger equation of the model, which includes only nearest
neighbor interactions, is written in a matrix formulation. In the uniform case,
the resulting Hamiltonian is proportional to the adjacency matrix of the
Apollonian network. The characterization of the electronic eigenstates is based
on the properties of the spectrum, which is characterized by a very large
degeneracy. The $2\pi /3$ rotation symmetry of the network and large number of
equivalent sites are reflected in all eigenstates, which are classified
according to their parity. Extended and localized states are identified by
evaluating the participation rate. Results for other two non-uniform models on
the Apollonian network are also presented. In one case, interaction is
considered to be dependent of the node degree, while in the other one, random
on-site energies are considered.


title:
Exact Solutions of the Klein-Gordon Equation for the Rosen-Morse type
  Potentials via Nikiforov-Uvarov Method

abstract:
  The exact solutions of the one-dimensional Klein-Gordon equation for the
Rosen-Morse type potential with equal scalar and vector potentials are
presented. First we briefly review Nikiforov-Uvarov mathematical method. Using
this method, wave-functions and corresponding exact energy equation are
obtained for the s-wave bound state. It has been shown that the results for
Rosen-Morse type potentials reduce to standard Rosen-Morse well and Eckart
potentials in the special case. The PT-symmetry for these potentials is also
considered.


title: On base station localization for state estimation over lossy networks

abstract:
  We consider a state estimation problem where observations are made by
multiple sensors. These observations are communicated over a lossy wireless
network to a central base station that computes estimates via a Kalman filter.
The goal is to determine the optimal location of the base station under a
certain class of packet loss probability models. It is shown in the two sensor
case that the base station is optimally located at one of the sensor locations.
Empirical evidence suggests that the result holds in some generality.


title:
Matter Coupling to Strong Electromagnetic Fields in Two-Level Quantum
  Systems with Broken Inversion Symmetry

abstract:
  We demonstrate theoretically the parametric oscillator behavior of a
two-level quantum system with broken inversion symmetry exposed to a strong
electromagnetic field. A multitude of resonance frequencies and additional
harmonics in the scattered light spectrum as well as altered Rabi frequency are
predicted to be inherent to such systems. In particular, dipole radiation at
the Rabi frequency appears to be possible. Since the Rabi frequency is
controlled by the strength of coupling electromagnetic field, the effect can
serve for the frequency-tuned parametric amplification and generation of
electromagnetic waves. Manifestation of the effect is discussed for III-nitride
quantum dots with strong build-in electric field breaking the inversion
symmetry. Terahertz emission from arrays of such quantum dots is shown to be
experimentally observable.


title: On the rank of elliptic curves

abstract: The paper proves that the Birch and Swinnerton-Dyer conjecture is false.


title:
Hyperfine Suppression of $2^3{\rm S}_1 - 3^3{\rm P}_J$ Transitions in
  $^3$He

abstract:
  Two anomalously weak transitions within the $2 ^3{\rm S}_1~-~3 ^3{\rm P}_J$
manifolds in $^3$He have been identified. Their transition strengths are
measured to be 1,000 times weaker than that of the strongest transition in the
same group. This dramatic suppression of transition strengths is due to the
dominance of the hyperfine interaction over the fine structure interaction. An
alternative selection rule based on \textit{IS}-coupling (where the nuclear
spin is first coupled to the total electron spin) is proposed. This provides
qualitative understanding of the transition strengths. It is shown that the
small deviations from the \textit{IS}-coupling model are fully accounted for by
an exact diagonalization of the strongly interacting states.


title:
Perspective Drawing of Surfaces with Line Hidden Line Elimination,
  Dibujando Superficies En Perspectiva Con Eliminacion De Lineas Ocultas

abstract:
  An efficient computer algorithm is described for the perspective drawing of a
wide class of surfaces. The class includes surfaces corresponding lo
single-valued, continuous functions which are defined over rectangular domains.
The algorithm automatically computes and eliminates hidden lines. The number of
computations in the algorithm grows linearly with the number of sample points
on the surface to be drawn. An analysis of the algorithm is presented, and
extensions lo certain multi-valued functions are indicated. The algorithm is
implemented and tested on .Net 2.0 platform that left interactive use. Running
times are found lo be exceedingly efficient for visualization, where
interaction on-line and view-point control, enables effective and rapid
examination of a surfaces from many perspectives.


title:
Spin polarization control through resonant states in an Fe/GaAs Schottky
  barrier

abstract:
  Spin polarization of the tunnel conductivity has been studied for Fe/GaAs
junctions with Schottky barriers. It is shown that band matching of resonant
interface states within the Schottky barrier defines the sign of spin
polarization of electrons transported through the barrier. The results account
very well for experimental results including the tunneling of photo-excited
electrons, and suggest that the spin polarization (from -100% to 100%) is
dependent on the Schottky barrier height. They also suggest that the sign of
the spin polarization can be controlled with a bias voltage.


title: Property $(T)$ for noncommutative universal lattices

abstract:
  We establish a new spectral criterion for Kazhdan's property $(T)$ which is
applicable to a large class of discrete groups defined by generators and
relations. As the main application, we prove property $(T)$ for the groups
$EL_n(R)$, where $n\geq 3$ and $R$ is an arbitrary finitely generated
associative ring. We also strengthen some of the results on property $(T)$ for
Kac-Moody groups from a paper of Dymara and Januszkiewicz (Invent. Math 150
(2002)).


title:
Preparation of Metal Mixed Plastic Superconductors: Electrical
  Properties of Tin-Antimony Thin Films on Plastic Substrates

abstract:
  Metal mixed polymers are a cheap and effective way to produce flexible metals
and superconductors. As part of an on-going effort to learn how to tune the
properties of these systems with ion implantation, we present a study of the
electrical properties of these systems prior to metal-mixing. We show that the
electrical properties of tin-antimony thin films are remarkably robust to
variations in the substrate morphology. We demonstrate that the optical
absorbance of the films at a fixed wavelength provides a reliable and
reproducible characterization of the relative film thickness. We find that as
the film thickness is reduced, the superconducting transition in the
unimplanted thin films is broadened, but the onset of the transition remains at
~3.7 K, the transition temperature of bulk Sn. This is in marked contrast to
the behavior of metal mixed films, which suggests that the metal mixing process
has a significant effect of the physics of the superconducting state beyond
that achieved by reducing the film thickness alone.


title:
Ultrafast pump-probe study of phase separation and competing orders in
  the underdoped (Ba,K)Fe$_{2}$As$_{2}$ superconductor

abstract:
  We report measurements of quasiparticle relaxation dynamics in the
high-temperature superconductor (Ba,K)Fe$_{2}$As$_{2}$ in optimally doped,
underdoped and undoped regimes. In the underdoped sample, spin-density wave
(SDW) order forms at $\sim$85 K, followed by superconductivity at $\sim$ 28 K.
We find the emergence of a normal-state order that suppresses SDW at a
temperature $T^{\ast} \sim$ 60 K and argue that this normal-state order is a
precursor to superconductivity.


title:
Minimal Energy Cost for Thermodynamic Information Processing:
  Measurement and Information Erasure

abstract:
  The fundamental lower bounds of the thermodynamic energy cost (work) needed
for the measurement and the erasure of information are found. The lower bound
for the erasure vindicates the "Landauer's principle" for a special case, but
otherwise implies its breakdown, indicating that no unique relationship exists
between logical reversibility and physical one. Our results constitute the
second law of "information thermodynamics", in which the information content
and thermodynamic variables are treated on an equal footing.


title: Group actions on median spaces

abstract:
  We investigate the geometry of median metric spaces. The group-theoretic
applications are towards Kazhdan's property (T) and Haagerup's property.


title:
Subvacuum effects of the quantum field on the dynamics of a test
  particle

abstract:
  We study the effects of the electromagnetic subvacuum fluctuations on the
dynamics of a nonrelativistic charged particle in a wavepacket. The influence
from the quantum field is expected to give an additional effect to the velocity
uncertainty of the particle. In the case of a static wavepacket, the observed
velocity dispersion is smaller in the electromagnetic squeezed vacuum
background than in the normal vacuum background. This leads to the subvacuum
effect. The extent of reduction in velocity dispersion associated with this
subvacuum effect is further studied by introducing a switching function. It is
shown that the slow switching process may make this subvacuum effect
insignificant. We also point out that when the center of the wavepacket
undergoes non-inertial motion, reduction in the velocity dispersion becomes
less effective with its evolution, no matter how we manipulate the
nonstationary quantum noise via the choice of the squeeze parameters. The role
of the underlying fluctuation-dissipation relation is discussed.


title:
On Gaussian MIMO BC-MAC Duality With Multiple Transmit Covariance
  Constraints

abstract:
  Owing to the structure of the Gaussian multiple-input multiple-output (MIMO)
broadcast channel (BC), associated optimization problems such as capacity
region computation and beamforming optimization are typically non-convex, and
cannot be solved directly. One feasible approach to these problems is to
transform them into their dual multiple access channel (MAC) problems, which
are easier to deal with due to their convexity properties. The conventional
BC-MAC duality is established via BC-MAC signal transformation, and has been
successfully applied to solve beamforming optimization,
signal-to-interference-plus-noise ratio (SINR) balancing, and capacity region
computation. However, this conventional duality approach is applicable only to
the case, in which the base station (BS) of the BC is subject to a single sum
power constraint. An alternative approach is minimax duality, established by Yu
in the framework of Lagrange duality, which can be applied to solve the
per-antenna power constraint problem. This paper extends the conventional
BC-MAC duality to the general linear constraint case, and thereby establishes a
general BC-MAC duality. This new duality is applied to solve the capacity
computation and beamforming optimization for the MIMO and multiple-input
single-output (MISO) BC, respectively, with multiple linear constraints.
Moreover, the relationship between this new general BC-MAC duality and minimax
duality is also presented. It is shown that the general BC-MAC duality offers
more flexibility in solving BC optimization problems relative to minimax
duality. Numerical results are provided to illustrate the effectiveness of the
proposed algorithms.


title:
Modulus stabilization of generalized Randall Sundrum model with bulk
  scalar field

abstract:
  We study the stabilization of inter-brane spacing modulus of generalized
warped brane models with a nonzero brane cosmological constant. Employing
Goldberger-Wise stabilization prescription of brane world models with a bulk
scalar field, we show that the stabilized value of the modulus generally
depends on the value of the brane cosmological constant. Our result further
reveals that the stabilized modulus value corresponding to a vanishingly small
cosmological constant can only resolve the gauge hierarchy problem
simultaneously. This in turn vindicates the original Randall-Sundrum model
where the 3-brane cosmological constant was chosen to be zero.


title: Electron spin relaxation in cubic GaN quantum dots

abstract:
  The spin relaxation time $T_{1}$ in zinc blende GaN quantum dot is
investigated for different magnetic field, well width and quantum dot diameter.
The spin relaxation caused by the two most important spin relaxation mechanisms
in zinc blende semiconductor quantum dots, {i.e.} the electron-phonon
scattering in conjunction with the Dresselhaus spin-orbit coupling and the
second-order process of the hyperfine interaction combined with the
electron-phonon scattering, are systematically studied. The relative importance
of the two mechanisms are compared in detail under different conditions. It is
found that due to the small spin orbit coupling in GaN, the spin relaxation
caused by the second-order process of the hyperfine interaction combined with
the electron-phonon scattering plays much more important role than it does in
the quantum dot with narrower band gap and larger spin-orbit coupling, such as
GaAs and InAs.


title: Topological defects in two-dimensional crystals

abstract:
  By using topological current theory, we study the inner topological structure
of the topological defects in two-dimensional (2D) crystal. We find that there
are two elementary point defects topological current in two-dimensional
crystal, one for dislocations and the other for disclinations. The topological
quantization and evolution of topological defects in two-dimensional crystals
are discussed. Finally, We compare our theory with Brownian-dynamics
simulations in 2D Yukawa systems.


title: Nonspreading wave packets in a general potential V(x,t) in one dimension

abstract:
  We discuss nonspreading wave packets in one dimensional Schr\"{o}dinger
equation. We derive general rules for constructing nonspreading wave packets
from a general potential $\textmd{V}(x,t)$. The essential ingredients of a
nonspreading wave packet, the shape function $f(x)$, the motion $d(t)$, the
phase function $\phi(x,t)$ are derived. Since the form of the shape of a
nonspreading wave packet does not change in time, the shape equation should be
time independent. We show that the shape function $f(x)$ is the eigenfunction
of the time independent Schr\"{o}dinger equation with an effective potential
$V_{\textmd{eff}}$ and an energy $E_{\textmd{eff}}$. We derive nonspreading
wave packets found by Schr\"{o}dinger, Senitzky, and Berry and Balazs as
examples. We show that most stationary potentials can only support stationary
nonspreading wave packets. We show how to construct moving nonspreading wave
packets from time dependent potentials, which drive nonspreading wave packets
into an arbitrary motion.


title: From Pet to Split

abstract:
  Various forms of the polynomial ergodic theorem (PET) which attracted
substantial attention in ergodic theory study the limits of expressions having
the form $1/N\sum_{n=1}^NT^{q_1(n)}f_1... T^{q_\ell (n)}f_\ell$ where $T$ is a
weakly mixing measure preserving transformation, $f_i$'s are bounded measurable
functions and $q_i$'s are polynomials taking on integer values on the integers.
Motivated partially by these results we obtain a central limit theorem for
expressions of the form $1/\sqrt{N}\sum_{n=1}^N (X_1(q_1(n))X_2(q_2(n))...
X_\ell(q_\ell(n))-a_1a_2... a_\ell)$ (sum-product limit theorem--SPLIT) where
$X_i$'s are fast $\alpha$-mixing bounded stationary processes, $a_j=EX_j(0)$
and $q_i$'s are positive functions taking on integer values on integers with
some growth conditions which are satisfied, for instance, when $q_i$'s are
polynomials of growing degrees. This result can be applied to the case when
$X_i(n)=T^nf_i$ where $T$ is a mixing subshift of finite type, a hyperbolic
diffeomorphism or an expanding transformation taken with a Gibbs invariant
measure, as well, as to the case when $X_i(n)=f_i(\xi_n)$ where $\xi_n$ is a
Markov chain satisfying the Doeblin condition considered as a stationary
process with respect to its invariant measure.


title:
Modelling interdependencies between the electricity and information
  infrastructures

abstract:
  The aim of this paper is to provide qualitative models characterizing
interdependencies related failures of two critical infrastructures: the
electricity infrastructure and the associated information infrastructure. The
interdependencies of these two infrastructures are increasing due to a growing
connection of the power grid networks to the global information infrastructure,
as a consequence of market deregulation and opening. These interdependencies
increase the risk of failures. We focus on cascading, escalating and
common-cause failures, which correspond to the main causes of failures due to
interdependencies. We address failures in the electricity infrastructure, in
combination with accidental failures in the information infrastructure, then we
show briefly how malicious attacks in the information infrastructure can be
addressed.


title:
The ADAPT Tool: From AADL Architectural Models to Stochastic Petri Nets
  through Model Transformation

abstract:
  ADAPT is a tool that aims at easing the task of evaluating dependability
measures in the context of modern model driven engineering processes based on
AADL (Architecture Analysis and Design Language). Hence, its input is an AADL
architectural model annotated with dependability-related information. Its
output is a dependability evaluation model in the form of a Generalized
Stochastic Petri Net (GSPN). The latter can be processed by existing
dependability evaluation tools, to compute quantitative measures such as
reliability, availability, etc.. ADAPT interfaces OSATE (the Open Source AADL
Tool Environment) on the AADL side and SURF-2, on the dependability evaluation
side. In addition, ADAPT provides the GSPN in XML/XMI format, which represents
a gateway to other dependability evaluation tools, as the processing techniques
for XML files allow it to be easily converted to a tool-specific GSPN.


title:
Software dependability modeling using an industry-standard architecture
  description language

abstract:
  Performing dependability evaluation along with other analyses at
architectural level allows both making architectural tradeoffs and predicting
the effects of architectural decisions on the dependability of an application.
This paper gives guidelines for building architectural dependability models for
software systems using the AADL (Architecture Analysis and Design Language). It
presents reusable modeling patterns for fault-tolerant applications and shows
how the presented patterns can be used in the context of a subsystem of a
real-life application.


title:
Use of abstract Hardy spaces, Real interpolation and Applications to
  bilinear operators

abstract:
  This paper can be considered as the sequel of [6], where the authors have
proposed an abstract construction of Hardy spaces H^1. They shew an
interpolation result for these Hardy spaces with the Lebesgue spaces. Here we
describe a more precise result using the real interpolation theory and we
clarify the use of Hardy spaces. Then with the help of the bilinear
interpolation theory, we then give applications to study bilinear operators on
Lebesgue spaces. These ideas permit us to study singular operators with
singularities similar to those of bilinear Calderon-Zygmund operators in a far
more abstract framework as in the euclidean case.


title: A Handy Tool for History Keeping of Geant4 Tracks -- J4HistoryKeeper --

abstract:
  The Particle Flow Analysis (PFA) is currently under intense studies as the
most promising way to achieve precision jet energy measurements required at the
future linear $e^+e^-$ collider. In order to optimize detector configurations
and to tune up the PFA it is crucial to identify factors that limit the PFA
performance and clarify the fundamental limits on the jet energy resolution
that remain even with the perfect PFA and an infinitely granular calorimeter.
This necessitates a tool to connect each calorimeter hit in particle showers to
its parent charged track, if any, and eventually all the way back to its
corresponding primary particle, while identifying possible interactions and
decays along the way. In order to realize this with a realistic memory space,
we have developed a set of C++ classes that facilitates history keeping of
particle tracks within the framework of Geant4. This software tool, hereafter
called J4HistoryKeeper, comes in handy in particular when one needs to stop
this history keeping for memory space economy at multiple geometrical
boundaries beyond which a particle shower is expected to start. In this paper
this software tool is described and applied to a generic detector model to
demonstrate its functionality.


title:
Mathematical Remarks on the Feynman Path Integral for Nonrelativistic
  Quantum Electrodynamics

abstract:
  The Feynman path integral for nonrelativistic quantum electrodynamics is
studied mathematically of a standard model in physics, where the
electromagnetic potential is assumed to be periodic with respect to a large box
and quantized thorough its Fourier coefficients. In physics, the Feynman path
integral for nonrelativistic quantum electrodynamics is defined very formally.
For example, as is often seen, even independent variables are not so clear.
First, the Feynman path integral is defined rigorously under the constraints
familiar in physics. Secondly, the Feynman path integral is also defined
rigorously without the constraints, which is stated in Feynman and Hibbs' book
without any comments. So, our definition may be completely new. Thirdly, the
vacuum and the state of photons of momentums and polarization states are
expressed by means of concrete functions of variables consisting of the Fourier
coefficients of the electromagnetic potential. Our results above have many
applications as is seen in Feynman and Hibbs' book, though the applications are
not rigorous so far. It is also proved rigorously by means of the distribution
theory that the Coulomb potentials between charged particles naturally appear
in the Feynman path integral above. As is well known, this shows that photons
give the Coulomb forth.


title: The local deflection of light

abstract:
  We have derived the relationship between the radial proper distance, h, and
the polar angle, phi, for a light ray that is emitted and travels in the
neighborhood of the Earth's surface. General relativity predicts that, even
locally, the equation which relates these two physical magnitudes differs from
the one stated by the principle of equivalence. More precisely, we have proved
that, in the weak field limit, the local physical trajectory, h=h(phi), is the
one that would correspond to a massive Newtonian particle in a field two times
greater. Therefore, and contrary to the generally accepted fact, the principle
of equivalence gives only 1/2 part of the general relativity local deflection
of light.


title:
Spatially-modulated Superfluid States in Fermionic Optical Ladder
  Systems with Repulsive Interactions

abstract:
  We investigate two-component ultracold fermionic atoms with repulsive
interactions trapped in an optical lattice with a ladder structure. By applying
the Bogoliubov-de Gennes equations to an effective t-J model in the strong
correlation limit, we discuss how the spatially-modulated spin-singlet pairs
with d-wave like symmetry are formed in the systems with trapping potentials.
Furthermore, a close examination of the condensation energy as well as the
local average of potential, kinetic and exchange energies by means of the
variational Monte Carlo method elucidates that local particle correlations
enhance the stability of the superfluid state via substantial energy gain due
to singlet pairing in the high particle density region.


title:
Bisimilarity and Behaviour-Preserving Reconfigurations of Open Petri
  Nets

abstract:
  We propose a framework for the specification of behaviour-preserving
reconfigurations of systems modelled as Petri nets. The framework is based on
open nets, a mild generalisation of ordinary Place/Transition nets suited to
model open systems which might interact with the surrounding environment and
endowed with a colimit-based composition operation. We show that natural
notions of bisimilarity over open nets are congruences with respect to the
composition operation. The considered behavioural equivalences differ for the
choice of the observations, which can be single firings or parallel steps.
Additionally, we consider weak forms of such equivalences, arising in the
presence of unobservable actions. We also provide an up-to technique for
facilitating bisimilarity proofs. The theory is used to identify suitable
classes of reconfiguration rules (in the double-pushout approach to rewriting)
whose application preserves the observational semantics of the net.


title: The cellular structure of the classifying spaces of finite groups

abstract:
  In this paper we complete the description of the $B\mathbb{Z}
/p$-cellularization of the classifying spaces of all finite groups, for all
primes $p$. The techniques are based in a careful analysis of the $p$-fusion
structure of the groups involved -with special attention to their strongly
closed subgroups- and Chach\'olski's description of the $A$-cellular
approximation.


title: A Deep 150 MHz GMRT Survey in Eridanus

abstract:
  We present results of a 150 MHz survey of a field centered on Epsilon
Eridani, undertaken with the Giant Metrewave Radio Telescope (GMRT). The survey
covers an area with a diameter of 2 deg, has a spatial resolution of 30" and a
noise level of 3.1 mJy at the pointing centre. These observations provide a
deeper and higher resolution view of the 150 MHz radio sky than the 7C survey
(although the 7C survey covers a much larger area). A total of 113 sources were
detected, most are point-like, but 20 are extended. We present an analysis of
these sources, in conjunction with the NVSS (at 1.4 GHz) and VLSS (at 74 MHz).
This process allowed us to identify 5 Ultra Steep Spectrum (USS) radio sources
that are candidate high redshift radio galaxies (HzRGs). In addition, we have
derived the dN/dS distribution for these observations and compare our results
with other low frequency radio surveys.


title: Quantum Interfaces Using Nanoscale Surface Plasmons

abstract:
  The strong coupling between individual optical emitters and propagating
surface plasmons confined to a conducting nanotip make this system act as an
ideal interface for quantum networks, through which a stationary qubit and a
flying photon (surface plasmon) qubit can be interconverted via a Raman
process. This quantum interface paves the way for many essential functions of a
quantum network, including sending, receiving, transferring, swapping, and
entangling qubits at distributed quantum nodes as well as a deterministic
source and an efficient detector of a single-photon. Numerical simulation shows
that this scheme is robust against experimental imperfections and has high
fidelity. Furthermore, being smaller this interface would significantly
facilitate the scalability of quantum computers.


title:
Luscher Term for k-string Potential from Holographic One Loop
  Corrections

abstract:
  We perform a systematic analysis of k-strings in the framework of the
gauge/gravity correspondence. We discuss the Klebanov-Strassler supergravity
background which is known to be dual to a confining supersymmetric gauge theory
with chiral symmetry breaking. We obtain the k-string tension in agreement with
expectations of field theory. Our main new result is the study of one-loop
corrections on the string theoretic side. We explicitly find the frequency
spectrum for both the bosons and the fermions for quadratic fluctuations about
the classical supergravity solution. Further we use the massless modes to
compute 1/L contributions to the one loop corrections to the k-string energy.
This corresponds to the Luscher term contribution to the k-string potential on
the gauge theoretic side of the correspondence.


title:
Measurement of the e+e- --> b anti-b cross section between sqrt(S)=10.54
  and 11.20 GeV

abstract:
  We report e+e- --> b anti-b cross section measurements by the BABAR
experiment performed during an energy scan in the range of 10.54 to 11.20 GeV
at the PEP-II e+e- collider. A total relative error of about 5% is reached in
more than three hundred center-of-mass energy steps, separated by about 5 MeV.
These measurements can be used to derive precise information on the parameters
of the Y(10860) and Y(11020) resonances. In particular we show that their
widths may be smaller than previously measured.


title:
Space-time attributes of physical objects and the laws of space-time
  physics

abstract:
  Physical time intervals are attributes of single physical object whereas
physical space intervals are a relational attribute of two physical objects.
Some consequences of the breaking of the space-time exchange symmetry inherent
in the Lorentz transformation following from the above distinction are
investigated. In particular, it is shown that the relativity of simultaneity
and length contraction effects which naively follow from space-time symmetry of
the Lorentz transformation do not occur. Seven laws describing the relation
between observations of space intervals, time intervals and velocities in
different reference frames are given. Only two of these laws are respected by
conventional special relativity theory.


title:
Perturbation theory of N point-mass gravitational lens systems without
  symmetry: small mass-ratio approximation

abstract:
  This paper makes the first systematic attempt to determine using perturbation
theory the positions of images by gravitational lensing due to arbitrary number
of coplanar masses without any symmetry on a plane, as a function of lens and
source parameters. We present a method of Taylor-series expansion to solve the
lens equation under a small mass-ratio approximation. First, we investigate
perturbative structures of a single-complex-variable polynomial, which has been
commonly used. Perturbative roots are found. Some roots represent positions of
lensed images, while the others are unphysical because they do not satisfy the
lens equation. This is consistent with a fact that the degree of the
polynomial, namely the number of zeros, exceeds the maximum number of lensed
images if N=3 (or more). The theorem never tells which roots are physical (or
unphysical). In this paper, unphysical ones are identified. Secondly, to avoid
unphysical roots, we re-examine the lens equation. The advantage of our method
is that it allows a systematic iterative analysis. We determine image positions
for binary lens systems up to the third order in mass ratios and for arbitrary
N point masses up to the second order. This clarifies the dependence on
parameters. Thirdly, the number of the images that admit a small mass-ratio
limit is less than the maximum number. It is suggested that positions of extra
images could not be expressed as Maclaurin series in mass ratios.
Magnifications are finally discussed.


title: A Generalized Composition of Quadratic Forms based on Quadratic Pairs

abstract:
  For quadratic spaces which represent 1 there is a characterization of
hermitian compositions in the language of algebras-with-involutions using the
even Clifford algebra. We extend this notion to define a generalized
composition based on quadratic pairs and determine the degrees of minimal
compositions for any given quadratic pair.


title: Bubbles in $^{34}$Si and $^{22}$O?

abstract:
  Bubble nuclei are characterized by a depletion of their central density.
Their existence is examined within three different theoretical frameworks: the
shell model as well as non-relativistic and relativistic microscopic mean-field
approaches. We propose $^{34}$Si and $^{22}$O as possible candidates for proton
and neutron bubble nuclei, respectively. In the case of $^{22}$O, we observe a
significant model dependence, thereby calling into question the bubble
structure of $^{22}$O. In contrast, an overall agreement among the models is
obtained for $^{34}$Si. Indeed, all models predict a central proton density
depletion of about 40%. This result provides strong evidence in favor of a
proton bubble in $^{34}$Si.


title:
Gauging the dark matter fraction in a $L_*$ S0 galaxy at z=0.47 through
  gravitational lensing from deep HST/ACS imaging

abstract:
  We analyze a new gravitational lens, OAC-GL J1223-1239, serendipitously found
in a deep I-band image of the Hubble Space Telescope (HST) Advanced Camera for
Surveys (ACS). The lens is a L_*, edge-on S0 galaxy at z=0.4656. The
gravitational arc has a radius of 0.42 arcsec. We have determined the total
mass and the dark matter (DM) fraction within the Einstein radius as a function
of the lensed source redshift, which is presently unknown. For z ~ 1.3, which
is in the middle of the redshift range plausible for the source according to
some external constraints, we find the central velocity dispersion to be ~180
km/s. With this value, close to that obtained by means of the Faber-Jackson
relation at the lens redshift, we compute a 30% DM fraction within the Einstein
radius (given the uncertainty in the source redshift, the allowed range for the
DM fraction is 25-35 % in our lensing model). When compared with the galaxies
in the local Universe, the lensing galaxy, OAC-GL J1223-1239 seems to fall in
the transition regime between massive DM dominated galaxies and lower-mass, DM
deficient systems.