title:
Foundations of a quantum gravity at large scales of length and its
  consequences for the dynamics of cosmological expansion

abstract:
  We attempt to find new symmetries in the space-time structure, leading to a
modified gravitation at large length scales, which provides the foundations of
a quantum gravity at very low energies. This search begins by considering a
unified model for electrodynamics and gravitation, so that the influence of the
gravitational field on the electrodynamics at very large distances leads to a
reformulation of our understanding about space-time through the elimination of
the classical idea of rest at quantum level. This leads us to a modification of
the relativistic theory by introducing the idea of a universal minimum speed
related to Planck minimum length. Such a speed, unattainable by the particles,
represents a privileged inertial reference frame associated with a universal
background field. The structure of space-time becomes extended due to such a
vacuum energy density, which leads to a cosmological anti-gravity, playing the
role of the cosmological constant. The tiny values of the vacuum energy density
and the cosmological constant are successfully obtained, being in agreement
with current observational results. We estimate the very high value of vacuum
energy density at Planck length scale. After we find the critical radius of the
universe, beyond which the accelerated expansion takes place. We show that such
a critical radius is $R_{uc}=r_g/2$, where $r_g=2GM/c^2$, being $r_g$ the
Shwarzschild radius of a sphere with a mass $M$ representing the total
attractive mass contained in our universe. And finally we obtain the radius
$R_{u0}=3r_g/4(>R_{uc})$ where we find the maximum rate of accelerated
expansion. For $R_u>R_{u0}$, the rate of acceleration decreases to zero at the
infinite, avoiding Big Rip.


title: Trouble with Physics?

abstract:
  This is a review of Lee Smolin's "The Trouble with Physics". The main gist of
the review is that the physics of the past three decades has been rich with new
discoveries in a large number of domains. The Standard Model, while providing a
successful framework for the electroweak and strong interactions still needs to
be developed further to fully account fot the mass of strong interaction data
collected over the decades. A multitude of new phenomena have been discovered
however, or predicted theoretically, in the physics of very low temperatures
(e.g. fractional Hall effect, Bose-Einstein condensation) and quantum
macroscopic effects (liquid crystals, high temperature superconductivity), some
of which remain to be fully explained. Therefore if there is any "Trouble with
Physics", as implied by the author of this book, it mainly concerns speculative
work on Superstring theory, which may or may not turn out to agree with the
results of observation. The subject as a whole does not appear to be in
trouble.

categories: physics.hist-ph hep-th physics.gen-ph physics.pop-ph


title:
Phase transition of computational power in the resource states for
  one-way quantum computation

abstract:
  We study how heralded qubit losses during the preparation of a
two-dimensional cluster state, a universal resource state for one-way quantum
computation, affect its computational power. Above the percolation threshold we
present a polynomial-time algorithm that concentrates a universal cluster
state, using resources that scale optimally in the size of the original
lattice. On the other hand, below the percolation threshold, we show that
single qubit measurements on the faulty lattice can be efficiently simulated
classically. We observe a phase transition at the threshold when the amount of
entanglement in the faulty lattice directly relevant to the computational power
changes exponentially.


title: Spin-Dependent Tunneling of Single Electrons into an Empty Quantum Dot

abstract:
  Using real-time charge sensing and gate pulsing techniques we measure the
ratio of the rates for tunneling into the excited and ground spin states of a
single-electron AlGaAs/GaAs quantum dot in a parallel magnetic field. We find
that the ratio decreases with increasing magnetic field until tunneling into
the excited spin state is completely suppressed. However, we find that by
adjusting the voltages on the surface gates to change the orbital configuration
of the dot we can restore tunneling into the excited spin state and that the
ratio reaches a maximum when the dot is symmetric.


title: Electronic transport in locally gated graphene nanoconstrictions

abstract:
  We have developed the combination of an etching and deposition technique that
enables the fabrication of locally gated graphene nanostructures of arbitrary
design. Employing this method, we have fabricated graphene nanoconstrictions
with local tunable transmission and characterized their electronic properties.
An order of magnitude enhanced gate efficiency is achieved adopting the local
gate geometry with thin dielectric gate oxide. A complete turn off of the
device is demonstrated as a function of the local gate voltage. Such strong
suppression of device conductance was found to be due to both quantum
confinement and Coulomb blockade effects in the constricted graphene
nanostructures.


title: Many-pole model of inelastic losses in x-ray absorption spectra

abstract:
  Inelastic losses are crucial to a quantitative analysis of x-ray absorption
spectra. However, current treatments are semi-phenomenological in nature. Here
a first-principles, many-pole generalization of the plasmon-pole model is
developed for improved calculations of inelastic losses. The method is based on
the GW approximation for the self-energy and real space multiple scattering
calculations of the dielectric function for a given system. The model retains
the efficiency of the plasmon-pole model and is applicable both to periodic and
aperiodic materials over a wide energy range. The same many-pole model is
applied to extended GW calculations of the quasiparticle spectral function.
This yields estimates of multi-electron excitation effects, e.g., the many-body
amplitude factor $S_0^2$ due to intrinsic losses. Illustrative calculations are
compared with other GW calculations of the self-energy, the inelastic mean free
path, and experimental x-ray absorption spectra.


title:
Isolated Eigenvalues of the Ferromagnetic Spin-J XXZ Chain with Kink
  Boundary Conditions

abstract:
  We investigate the low-lying excited states of the spin J ferromagnetic XXZ
chain with Ising anisotropy Delta and kink boundary conditions. Since the third
component of the total magnetization, M, is conserved, it is meaningful to
study the spectrum for each fixed value of M. We prove that for J>= 3/2 the
lowest excited eigenvalues are separated by a gap from the rest of the
spectrum, uniformly in the length of the chain. In the thermodynamic limit,
this means that there are a positive number of excitations above the ground
state and below the essential spectrum.

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


title:
Residual Velocities in Steady Free Boundary Value Problems of Vector
  Laplacian Type

abstract:
  This paper describes a technique to determine the linear well-posedness of a
general class of vector elliptic problems that include a steady interface, to
be determined as part of the problem, that separates two subdomains. The
interface satisfies mixed Dirichlet and Neumann conditions. We consider ``2+2''
models, meaning two independent variables respectively on each subdomain. The
governing equations are taken to be vector Laplacian, to be able to make
analytic progress. The interface conditions can be classified into four large
categories, and we concentrate on the one with most physical interest. The
well-posedness criteria in this case are particularly clear. In many physical
cases, the movement of the interface in time-dependent situations can be
reduced to a normal motion proportional to the residual in one of the steady
state interface conditions (the elliptic interior problems and the other
interface conditions are satisfied at each time). If only the steady state is
of interest, one can consider using other residuals for the normal velocity.
Our analysis can be extended to give insight into choosing residual velocities
that have superior numerical properties. Hence, in the second part, we discuss
an iterative method to solve free boundary problems. The advantages of the
correctly chosen, non-physical residual velocities are demonstrated in a
numerical example, based on a simplified model of two-phase flow with phase
change in porous media.


title: CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates

abstract:
  We describe a uniform all-sky survey of bright blazars, selected primarily by
their flat radio spectra, that is designed to provide a large catalog of likely
gamma-ray AGN. The defined sample has 1625 targets with radio and X-ray
properties similar to those of the EGRET blazars, spread uniformly across the
|b| > 10 deg sky. We also report progress toward optical characterization of
the sample; of objects with known R < 23, 85% have been classified and 81% have
measured redshifts. One goal of this program is to focus attention on the most
interesting (e.g., high redshift, high luminosity, ...) sources for intensive
multiwavelength study during the observations by the Large Area Telescope (LAT)
on GLAST.


title: LAQGSM03.03 Upgrade and its Validation

abstract:
  This paper presents part of an internal LANL Progress Report on LAQGSM03.03,
an upgrade of the Los Alamos version of the Quark-Gluon String Model event
generator for MCNPX/6 and MARS15 transport codes and on its validation and
testing against a large variety of recent measurements. We present here an
analysis with LAQGSM03.03 of the recent PHENIX mid-rapidity spectra of pi+,
pi-, K+, K-, p, and p-bar produced in ultra-relativistic p + p interactions at
sqrt(s) = 200 GeV; GSI cross sections for the fragmentation of Pb208 at 1
GeV/nucleon on Be9; fragmentation cross sections of Si28 on H, C, Al, Cu, Sn,
and Pb at energies from 290 to 1200 MeV/nucleon measred recently at HIMAC and
BNL; recent HIMAC data on B, Be, Li, and He production cross sections from
fragmentation of C12 on H, C, Al, Cu, Sn, and Pb at 290 and 400 MeV/nucleon;
BNL data on fragmentation cross sections of Fe56 on H, C, Al, Cu, and Pb
targets at 1.05 GeV/nucleon; recent pi+ and pi- spectra from 6.4, 12.3, and
17.5 GeV/c p + Be9 from the E910 BNL measurements; and fragmentation cross
sections of Ca40, Ca48, Ni58, and Ni64 on Be9 and Ta181 at 140 MeV/nucleon, and
of Kr86 at 64 MeV/nucleon on the same targets measured recently at NSCL-MSU and
RARF-RIKEN, respectively.


title: The Fundamental Plane of Bulges at Intermediate Redshift

abstract:
  We report on a new study aimed at understanding the diversity and
evolutionary properties of distant galactic bulges in the context of
well-established trends for pure spheroidal galaxies. Bulges have been isolated
for a sample of 137 spiral galaxies in the GOODS fields within the redshift
range 0.1 < z < 1.2. Using proven photometric techniques we determine for each
galaxy the characteristic parameters (size, surface brightness, profile shape)
in the 4 GOODS-ACS imaging bands of both the disk and bulge components. Using
the DEIMOS spectrograph on Keck, precision stellar velocity dispersions were
secured for a sizeable fraction of the bulges. This has enabled us to compare
the Fundamental Plane of our distant bulges with that of field spheroidal
galaxies in a similar redshift range. Bulges in spiral galaxies with a
bulge-to-total luminosity ratio (B/T) > 0.2 show very similar patterns of
evolution to those seen for low luminosity spheroidals. To first order, their
recent mass assembly histories are equivalent.


title: Symmetrized cut-join equation of Marino-Vafa formula

abstract:
  In this note, we symmetrized the cut-join equation from the proof of
Marino-Vafa formula by applying a transcendental changing of variable. One can
derive more recursion formulas of Hodge integrals out of this polynomial
equations. We also give some applications.


title: Undecidability in function fields of positive characteristic

abstract:
  We prove that the first-order theory of any function field K of
characteristic p>2 is undecidable in the language of rings without parameters.
When K is a function field in one variable whose constant field is algebraic
over a finite field, we can also prove undecidability in characteristic 2. The
proof uses a result by Moret-Bailly about ranks of elliptic curves over
function fields.


title:
Addendum to the paper "Two-Dimensional Infinite Prandtl Number
  Convection: Structure of Bifurcated Solutions, J. Nonlinear Sci., 17(3),
  199-220, 2007"

abstract:
  The main objective of this addendum to the mentioned article by Park is to
provide some remarks on bifurcation theories for nonlinear partial differential
equations (PDE) and their applications to fluid dynamics problems. We only wish
to comment and list some related literatures, without any intention to provide
a complete survey.


title: How do black holes move, as quantum objects or as classical objects?

abstract:
  Results of a recent study of the transition between quantum and classical
behavior are applied to black holes. The study led to a criterion separating
quantum from classical behavior on the basis of mass or size, dependent on
local effects of cosmic expansion. Application of this criterion to black holes
indicates that the motion of smaller black holes will be characteristically
quantum mechanical, while the motion of larger black holes must be classical,
with a threshold distinguishing these behaviors at a Schwartzschild radius of
roughly the size of a nucleon.


title: Non-semisimple Macdonald polynomials

abstract:
  The paper is mainly devoted to the irreducibility of the polynomial
representation of the double affine Hecke algebra for an arbitrary reduced root
systems and generic "central charge" q. The technique of intertwiners in the
non-semisimple variant is the main tool. We introduce Macdonald's
non-semisimple polynomials and use them to analyze the reducibility of the
polynomial representation in terms of the affine exponents, counterparts of the
classical Coxeter exponents. The focus is on the principal aspects of the
technique of intertwiners, including related problems in the theory of reduced
decompositions on affine Weyl groups.


title:
Experimental evidence of a natural parity state in $^{26}$Mg and its
  impact to the production of neutrons for the s process

abstract:
  We have studied natural parity states in $^{26}$Mg via the
$^{22}$Ne($^{6}$Li,d)$^{26}$Mg reaction. Our method significantly improves the
energy resolution of previous experiments and, as a result, we report the
observation of a natural parity state in $^{26}$Mg. Possible spin-parity
assignments are suggested on the basis of published $\gamma$-ray decay
experiments. The stellar rate of the $^{22}$Ne($\alpha$,$\gamma$)$^{26}$Mg
reaction is reduced and may give rise to an increase in the production of
s-process neutrons via the $^{22}$Ne($\alpha$,n)$^{25}$Mg reaction.


title:
Experiments with small helicopter automated landings at unusual
  attitudes

abstract:
  This paper describes a set of experiments involving small helicopters landing
automated landing at unusual attitudes. By leveraging the increased agility of
small air vehicles, we show that it is possible to automatically land a small
helicopter on surfaces pitched at angles up to 60 degrees. Such maneuvers
require considerable agility from the vehicle and its avionics system, and they
pose significant technical and safety challenges. Our work builds upon previous
activities in human-inspired, high-agility flight for small rotorcraft.
However, it was not possible to leverage manual flight test data to extract
landing maneuvers due to stringent attitude and position control requirements.
Availability of low-cost, local navigation systems requiring no on-board
instrumentation has proven particularly important for these experiments to be
successful.


title:
Electromagnetic form factors of the pion and kaon from the instanton
  vacuum

abstract:
  We investigate the pion and kaon (pi^+, K^+, K^0) electromagnetic form
factors in the space-like region: Q^2 ~< 1 GeV, based on the gauged low-energy
effective chiral action from the instanton vacuum in the large N_c limit.
Explicit flavor SU(3) symmetry breaking is taken into account. The nonlocal
contributions turn out to be crucial to reproduce the experimental data. While
the pion electromagnetic form factor is in good agreement with the data, the
kaon one seems underestimated. We also calculate the electromagnetic charge
radii for the pion and kaon: <r^2>_{pi^+}=0.455 fm^2, <r^2>_{K^+}=0.486 fm^2
and <r^2>_{K^0}=-0.055 fm^2 without any adjustable free parameter except for
the average instanton size and inter-instanton distance, and they are
compatible with the experimental data. The low-energy constant L_9 in the large
N_c limit is estimated to be 8.42*10^{-3} from the pion charge radius.


title: On exit times of Levy-driven Ornstein--Uhlenbeck processes

abstract:
  We prove two martingale identities which involve exit times of Levy-driven
Ornstein--Uhlenbeck processes. Using these identities we find an explicit
formula for the Laplace transform of the exit time under the assumption that
positive jumps of the Levy process are exponentially distributed.


title: Bounds on the mixing enhancement for a stirred binary fluid

abstract:
  The Cahn-Hilliard equation describes phase separation in binary liquids. Here
we study this equation with spatially-varying sources and stirring, or
advection. We specialize to symmetric mixtures and time-independent sources and
discuss stirring strategies that homogenize the binary fluid. By measuring
fluctuations of the composition away from its mean value, we quantify the
amount of homogenization achievable. We find upper and lower bounds on our
measure of homogenization using only the Cahn-Hilliard equation and the
incompressibility of the advecting flow. We compare these theoretical bounds
with numerical simulations for two model flows: the constant flow, and the
random-phase sine flow. Using the sine flow as an example, we show how our
bounds on composition fluctuations provide a measure of the effectiveness of a
given stirring protocol in homogenizing a phase-separating binary fluid.


title: Heat Transfer in Underground Rail Tunnels

abstract:
  The transfer of heat between the air and surrounding soil in underground
tunnels ins investigated, as part of the analysis of environmental conditions
in underground rail systems. Using standard turbulent modelling assumptions,
flow profiles are obtained in both open tunnels and in the annulus between a
tunnel wall and a moving train, from which the heat transfer coefficient
between the air and tunnel wall is computed. The radial conduction of heat
through the surrounding soil resulting from changes in the temperature of air
in the tunnel are determined. An impulse change and an oscillating tunnel air
temperature are considered separately. The correlations between fluctuations in
heat transfer coefficient and air temperature are found to increase the mean
soil temperature. Finally, a model for the coupled evolution of the air and
surrounding soil temperature along a tunnel of finite length is given.


title:
General Non-extremal Rotating Charged Godel Black Holes in Minimal
  Five-Dimensional Gauged Supergravity

abstract:
  We present the general exact solutions for non-extremal rotating charged
black holes in the Godel universe of five-dimensional minimal supergravity
theory. They are uniquely characterized by four non-trivial parameters, namely
the mass $m$, the charge $q$, the Kerr equal rotation parameter $a$, and the
Godel parameter $j$. We calculate the conserved energy, angular momenta and
charge for the solutions and show that they completely satisfy the first law of
black hole thermodynamics. We also study the symmetry and separability of the
Hamilton-Jacobi and the massive Klein-Gordon equations in these
Einstein-Maxwell-Chern-Simons-Godel black hole backgrounds.

categories: hep-th astro-ph gr-qc hep-ph math-ph math.MP quant-ph


title:
Mutation-selection balance with recombination: convergence to
  equilibrium for polynomial selection costs

abstract:
  We study a continuous-time dynamical system that models the evolving
distribution of genotypes in an infinite population where genomes may have
infinitely many or even a continuum of loci, mutations accumulate along
lineages without back-mutation, added mutations reduce fitness, and
recombination occurs on a faster time scale than mutation and selection. Some
features of the model, such as existence and uniqueness of solutions and
convergence to the dynamical system of an approximating sequence of discrete
time models, were presented in earlier work by Evans, Steinsaltz, and Wachter
for quite general selective costs. Here we study a special case where the
selective cost of a genotype with a given accumulation of ancestral mutations
from a wild type ancestor is a sum of costs attributable to each individual
mutation plus successive interaction contributions from each $k$-tuple of
mutations for $k$ up to some finite ``degree''. Using ideas from complex
chemical reaction networks and a novel Lyapunov function, we establish that the
phenomenon of mutation-selection balance occurs for such selection costs under
mild conditions. That is, we show that the dynamical system has a unique
equilibrium and that it converges to this equilibrium from all initial
conditions.


title: Asymptotics for the Wiener sausage among Poissonian obstacles

abstract:
  We consider the Wiener sausage among Poissonian obstacles. The obstacle is
called hard if Brownian motion entering the obstacle is immediately killed, and
is called soft if it is killed at certain rate. It is known that Brownian
motion conditioned to survive among obstacles is confined in a ball near its
starting point. We show the weak law of large numbers, large deviation
principle in special cases and the moment asymptotics for the volume of the
corresponding Wiener sausage. One of the consequence of our results is that the
trajectory of Brownian motion almost fills the confinement ball.


title:
Transversely Polarized Drell-Yan Process and Soft Gluon Resummation in
  QCD

abstract:
  We calculate the transverse-momentum $Q_T$ spectrum of the dilepton in the
transversely polarized Drell-Yan process on the basis of the factorization
theorem in QCD. We take into account universal logarithmically enhanced
corrections in edge region of phase space by resumming multiple soft-gluon
emissions to all orders in the small $Q_T$ region.


title:
Spectrum and polarization of coherent and incoherent radiation and the
  LPM effect in oriented single crystal

abstract:
  The spectrum and the circular polarization of radiation from longitudinally
polarized high-energy electrons in oriented single crystal are considered using
the method which permits inseparable consideration of both the coherent and the
incoherent mechanisms of photon emission. The spectral and polarization
properties of radiation are obtained and analyzed. It is found that in some
part of spectral distribution the influence of multiple scattering (the
Landau-Pomeranchuk-Migdal (LPM) effect) attains the order of 7 percent. The
same is true for the influence of multiple scattering on the polarization part
of the radiation intensity. The degree of circular polarization of total
intensity of radiation is found. It is shown that the influence of multiple
scattering on the photon polarization is similar to the influence of the LPM
effect on the total intensity of radiation: it appears only for relatively low
energies of radiating electron and has the order of 1 percent, while at higher
energies the crystal field action excludes the LPM effect.


title: Greybody Factor and Hawking Radiation of Charged Dilatonic Black Holes

abstract:
  The greybody factor and the Hawking temperature for a class of asymptotically
flat charged dilatonic black holes are computed by using the low-energy
dynamics of scalar fields in the black hole background. In the semi-classical
approximation, the Hawking temperature has a good agreement with the one
computed from the surface gravity, which is independent of the magnetic (or
electric) charges of dilatonic black holes.


title: Dynamical tunneling in molecules: Quantum routes to energy flow

abstract:
  Dynamical tunneling, introduced in the molecular context, is more than two
decades old and refers to phenomena that are classically forbidden but allowed
by quantum mechanics. On the other hand the phenomenon of intramolecular
vibrational energy redistribution (IVR) has occupied a central place in the
field of chemical physics for a much longer period of time. Although the two
phenomena seem to be unrelated several studies indicate that dynamical
tunneling, in terms of its mechanism and timescales, can have important
implications for IVR. Examples include the observation of local mode doublets,
clustering of rotational energy levels, and extremely narrow vibrational
features in high resolution molecular spectra. Both the phenomena are strongly
influenced by the nature of the underlying classical phase space. This work
reviews the current state of understanding of dynamical tunneling from the
phase space perspective and the consequences for intramolecular vibrational
energy flow in polyatomic molecules.


title:
Physical Meaning of Hermiticity and Shortcomings of the Composite
  (Hermitian + non-Hermitian) Quantum Theory of Gunther and Samsonov

abstract:
  In arXiv:0709.0483 Gunther and Samsonov outline a ``generalization'' of
quantum mechanics that involves simultaneous consideration of Hermitian and
non-Hermitian operators and promises to be ``capable to produce effects beyond
those of standard Hermitian quantum mechanics.'' We give a simple physical
interpretation of Hermiticity and discuss in detail the shortcomings of the
above-mentioned composite quantum theory. In particular, we show that the
corresponding ``generalization of measurement theory'' suffers from a dynamical
inconsistency and that it is by no means adequate to replace the standard
measurement theory.


title: On the Four Vertex Theorem on planes with radial density $e^{\phi(r)}$

abstract:
  It is showed that on a plane with a radial density the Four Vertex Theorem
holds for the class of all simple closed curves if and only if the density is
constant. But for the class of simple closed curves that are invariant under a
rotation about the origin, the Four Vertex Theorem holds for every radial
density.


title: Difference sets and Polynomials of prime variables

abstract:
  Let \psi(x) be a polynomial with rational coefficients. Suppose that \psi has
the positive leading coefficient and zero constant term. Let A be a set of
positive integers with the positive upper density. Then there exist x,y\in A
and a prime p such that x-y=\psi(p-1). Furthermore, if P be a set of primes
with the positive relative upper density, then there exist x,y\in P and a prime
p such that x-y=\psi(p-1).


title: Two Ferromagnetic Phases in Spin-Fermion Systems

abstract:
  We consider spin-fermion systems which get their magnetic properties from a
system of localized magnetic moments being coupled to conducting electrons. The
dynamical degrees of freedom are spin-$s$ operators of localized spins and
spin-1/2 fermi operators of itinerant electrons. We develop modified spin-wave
theory and obtain that system has two ferromagnetic phases. At the
characteristic temperature T* the magnetization of itinerant electrons becomes
zero, and high temperature ferromagnetic phase (T*<T<T_C) is a phase where only
localized electrons give contribution to the magnetization of the system. An
anomalous increasing of magnetization below T* is obtained in a good agrement
with experimental measurements of the ferromagnetic phase of UGe2.


title: Thermal Waves in Irradiated Protoplanetary Disks

abstract:
  Protoplanetary disks are mainly heated by radiation from the central star.
Since the incident stellar flux at any radius is sensitive to the disk
structure near that location, an unstable feedback may be present. Previous
investigations show that the disk would be stable to finite-amplitude
temperature perturbations if the vertical height of optical surface is
everywhere directly proportional to the gas scale height and if the intercepted
fraction of stellar radiation is determined from the local grazing angle. We
show that these assumptions may not be generally applicable. Instead, we
calculate the quasi-static thermal evolution of irradiated disks by directly
integrating the global optical depths to determine the optical surface and the
total emitting area-filling factor of surface dust. We show that, in disks with
modest mass accretion rates, thermal waves are spontaneously and continually
excited in the outer disk, propagate inward through the planet-forming domains,
and dissipated at small radii where viscous dissipation is dominant. This state
is quasi-periodic over several thermal timescales and its pattern does not
depend on the details of the opacity law. The viscous dissipation resulting
from higher mass accretion stabilizes this instability such that an
approximately steady state is realized throughout the disk. In passive
protostellar disks, especially transitional disks, these waves induce
significant episodic changes in SEDs, on the time scales of years to decades,
because the midplane temperatures can vary by a factor of two between the
exposed and shadowed regions. The transitory peaks and troughs in the potential
vorticity distribution may also lead to baroclinic instability and excite
turbulence in theplanet-forming regions.


title:
ZEN2: A narrow J-band search for z~9 Lya emitting galaxies directed
  towards three lensing clusters

abstract:
  We present the results of a continuing survey to detect Lya emitting galaxies
at redshifts z~9: the ZEN ("z equals nine'') survey. We have obtained deep
VLT/ISAAC observations in the narrow J-band filter NB119 directed towards three
massive lensing clusters: Abell clusters 1689, 1835, and 114. The foreground
clusters provide a magnified view of the distant universe and permit a
sensitive test for the presence of very high-redshift galaxies. We search for
z~9 Lya emitting galaxies displaying a significant narrow-band excess relative
to accompanying J-band observations that remain undetected in HST/ACS optical
images of each field. No sources consistent with this criterion are detected
above the unlensed 90% point-source flux limit of the narrow-band image,
F_NB=3.7e-18 ergs/s/cm2. To date, the total coverage of the ZEN survey has
sampled a volume at z~9 of approximately 1700 co-moving Mpc3 to a Lya emission
luminosity of 1e43 erg/s. We conclude by considering the prospects for
detecting z~9 Lya emitting galaxies in light of both observed galaxy properties
at z<7 and simulated populations at z>7.


title: Relative Singularity Categories and Gorenstein-Projective Modules

abstract:
  We introduce the notion of relative singularity category with respect to any
self-orthogonal subcategory $\omega$ of an abelian category. We introduce the
Frobenius category of $\omega$-Cohen-Macaulay objects, and under some
reasonable conditions, we show that the stable category of
$\omega$-Cohen-Macaulay objects is triangle-equivalent to the relative
singularity category. As applications, we relate the stable category of
(unnecessarily finitely-generated) Gorenstein-projective modules with
singularity categories of rings. We prove that for a Gorenstein ring, the
stable category of Gorenstein-projective modules is compactly generated and its
compact objects coincide with finitely-generated Gorenstein-projective modules
up to direct summands.


title:
Magnetic Phase Transitions in One-dimensional Strongly Attractive
  Three-Component Ultracold Fermions

abstract:
  We investigate the nature of trions, pairing and quantum phase transitions in
one-dimensional strongly attractive three-component ultracold fermions in
external fields. Exact results for the groundstate energy, critical fields,
magnetization and phase diagrams are obtained analytically from the Bethe
ansatz solutions. Driven by Zeeman splitting, the system shows exotic phases of
trions, bound pairs, a normal Fermi liquid and four mixtures of these states.
Particularly, a smooth phase transition from a trionic phase into a pairing
phase occurs as the highest hyperfine level separates from the two lower energy
levels. In contrast, there is a smooth phase transition from the trionic phase
into a normal Fermi liquid as the lowest level separates from the two higher
levels.


title: "Slow Light" and "Slow Current"

abstract:
  It is shown that the effect of hole-burning under conditions of coherent
population oscillations as well as the light pulse delay in a saturable
absorber (a modification of the "slow light" effect) can be interpreted, in a
comprehensive way, in terms of {\it intensity spectrum} of the light and {\it
intensity-related susceptibility} of the non-linear medium. The physical
content of these effects is illustrated by a simple electric circuit with a
non-linear resistor which realizes a full analog of the saturable absorber. In
this case the effect of hole-burning in the absorption spectrum of the medium
is converted in to the effect of hole-burning in the frequency dependence of
resistance of the non-linear resistor and the effect of "slow light" -- in to
the effect of "slow current".


title: Covariant Calculus for Effective String Theories

abstract:
  A covariant calculus for the construction of effective string theories is
developed. Effective string theory, describing quantum string-like excitations
in arbitrary dimension, has in the past been constructed using the principles
of conformal field theory, but not in a systematic way. Using the freedom of
choice of field definition, a particular field definition is made in a
systematic way to allow an explicit construction of effective string theories
with manifest exact conformal symmetry. The impossibility of a manifestly
invariant description of the Polchinski-Strominger Lagrangian is demonstrated
and its meaning is explained.


title:
Magnetohydrodynamics of Neutrino-Cooled Accretion Tori around a Rotating
  Black Hole in General Relativity

abstract:
  We present our first numerical results of axisymmetric magnetohydrodynamic
simulations for neutrino-cooled accretion tori around rotating black holes in
general relativity. We consider tori of mass $\sim 0.1$--0.4$M_{\odot}$ around
a black hole of mass $M=4M_{\odot}$ and spin $a=0$--$0.9M$; such systems are
candidates for the central engines of gamma-ray bursts (GRBs) formed after the
collapse of massive rotating stellar cores and the merger of a black hole and a
neutron star. In this paper, we consider the short-term evolution of a torus
for a duration of $\approx 60$ ms, focusing on short-hard GRBs. Simulations
were performed with a plausible microphysical equation of state that takes into
account neutronization, the nuclear statistical equilibrium of a gas of free
nucleons and $\alpha$-particles, black body radiation, and a relativistic Fermi
gas (neutrinos, electrons, and positrons). Neutrino-emission processes, such as
$e^{\pm}$ capture onto free nucleons, $e^{\pm}$ pair annihilation, plasmon
decay, and nucleon-nucleon bremsstrahlung are taken into account as cooling
processes. Magnetic braking and the magnetorotational instability in the
accretion tori play a role in angular momentum redistribution, which causes
turbulent motion, resultant shock heating, and mass accretion onto the black
hole. The mass accretion rate is found to be $\dot M_* \sim 1$--$10
M_{\odot}$/s, and the shock heating increases the temperature to $\sim 10^{11}$
K. This results in a maximum neutrino emission rate of $L_{\nu}=$ several
$\times 10^{53}$ ergs/s and a conversion efficiency $L_{\nu}/\dot M_* c^2$ on
the order of a few percent for tori with mass $M_{\rm t} \approx
0.1$--0.4$M_{\odot}$ and for moderately high black hole spins.


title:
K-theory of quiver varieties, q-Fock space and nonsymmetric Macdonald
  polynomials

abstract:
  We have two constructions of the level-$(0,1)$ irreducible representation of
the quantum toroidal algebra of type $A$. One is due to Nakajima and
Varagnolo-Vasserot. They constructed the representation on the direct sum of
the equivariant K-groups of the quiver varieties of type $\hat{A}$. The other
is due to Saito-Takemura-Uglov and Varagnolo-Vasserot. They constructed the
representation on the q-deformed Fock space introduced by Kashiwara-Miwa-Stern.
  In this paper we give an explicit isomorphism between these two
constructions. For this purpose we construct simultaneous eigenvectors on the
q-Fock space using nonsymmetric Macdonald polynomials. Then the isomorphism is
given by corresponding these vectors to the torus fixed points on the quiver
varieties.


title:
Cohomology of $\mathfrak {osp}(1|2)$ acting on linear differential
  operators on the supercircle $S^{1|1}

abstract:
  We compute the first cohomology spaces
$H^1(\mathfrak{osp}(1|2);\mathfrak{D}_{\lambda,\mu})$ ($\lambda,
\mu\in\mathbb{R}$) of the Lie superalgebra $\mathfrak{osp}(1|2)$ with
coefficients in the superspace $\mathfrak{D}_{\lambda,\mu}$ of linear
differential operators acting on weighted densities on the supercircle
$S^{1|1}$. The structure of these spaces was conjectured in \cite{gmo}. In
fact, we prove here that the situation is a little bit more complicated. (To
appear in LMP.)


title: Feynman integrals and difference equations

abstract:
  We report on the calculation of multi-loop Feynman integrals for single-scale
problems by means of difference equations in Mellin space. The solution to
these difference equations in terms of harmonic sums can be constructed
algorithmically over difference fields, the so-called Pi-Sigma-fields. We test
the implementaion of the Mathematica package Sigma on examples from recent
higher order perturbative calculations in Quantum Chromodynamics.


title:
Combining directional light output and ultralow loss in deformed
  microdisks

abstract:
  A drawback of high-quality modes in optical microdisks is their isotropic
light emission characteristics. Here we report a novel, robust, and general
mechanism that results in highly directional light emission from those modes.
This surprising finding is explained by a combination of wave phenomena (wave
localization along unstable periodic ray trajectories) and chaotic ray dynamics
in open systems (escape along unstable manifolds). The emission properties
originating in the chaotic ray dynamics permit directional light output even
from microlasers operating in the common multi-mode regime. We demonstrate our
novel mechanism for the limacon billiard family and find directional emission
with narrow angular divergence for a significant range of geometries and
material parameters.


title: Variational local structure estimation for image super-resolution

abstract:
  Super-resolution is an important but difficult problem in image/video
processing. If a video sequence or some training set other than the given
low-resolution image is available, this kind of extra information can greatly
aid in the reconstruction of the high-resolution image. The problem is
substantially more difficult with only a single low-resolution image on hand.
The image reconstruction methods designed primarily for denoising is
insufficient for super-resolution problem in the sense that it tends to
oversmooth images with essentially no noise. We propose a new adaptive linear
interpolation method based on variational method and inspired by local linear
embedding (LLE). The experimental result shows that our method avoids the
problem of oversmoothing and preserves image structures well.


title: Isospin Matter in AdS/QCD

abstract:
  We study strange and isospin asymmetric matter in a bottom-up AdS/QCD model.
We first consider isospin matter, which has served as a good testing ground for
nonperturbative QCD. We calculate the isospin chemical potential dependence of
hadronic observables such as the masses and the decay constants of the
pseudo-scalar, vector, and axial-vector mesons. We discuss a possibility of the
charged pion condensation in the matter within the bottom-up AdS/QCD model.
Then, we study the properties of the hadronic observables in strange matter. We
calculate the deconfinement temperature in strange and isospin asymmetric
matter. One of the interesting results of our study is that the critical
temperature at a fixed baryon number density increases when the strangeness
chemical potential is introduced. This suggests that if matter undergoes a
first-order transition to strange matter, the critical temperature shows a
sudden jump at the transition point.


title: Deformation potential dominated phonons in ZnS quantum dots

abstract:
  Strong deformation potential (DP) dominated Raman spectra are reported for
quantum confined cubic ZnS nanoclusters under off-resonance conditions allowed
only in quantum dots. A flurry of zone boundary phonons is demonstrated in the
scattering process. Transverse optic (TO) mode in the multi-phonon process
shows only even order overtones suggesting the dominance of a two-phonon
process (having large DP value in ZnS) and its integral multiples. Two-phonon
TO modes corresponding to A1 and B2 symmetries are also demonstrated under
off-resonance conditions which are allowed only in quantum dots.


title: A parametrized version of the Borsuk Ulam theorem

abstract:
  The main result of this note is a parametrized version of the Borsuk-Ulam
theorem. We show that for a continuous family of Borsuk-Ulam situations,
parameterized by points of a compact manifold W, its solution set also depends
continuously on the parameter space W. Continuity here means that the solution
set supports a homology class which maps onto the fundamental class of W. When
W is a subset of Euclidean space, we also show how to construct such a
continuous family starting from a family depending in the same way continuously
on the points of the boundary of W. This solves a problem related to a
conjecture which is relevant for the construction of equilibrium strategies in
repeated two-player games with incomplete information. A new method (of
independent interest) used in this context is a canonical symmetric squaring
construction in Cech homology with coefficients in Z/2Z.


title: A Review of Target Mass Corrections

abstract:
  With recent advances in the precision of inclusive lepton--nuclear scattering
experiments, it has become apparent that comparable improvements are needed in
the accuracy of the theoretical analysis tools. In particular, when extracting
parton distribution functions in the large-x region, it is crucial to correct
the data for effects associated with the nonzero mass of the target. We present
here a comprehensive review of these target mass corrections (TMC) to structure
functions data, summarizing the relevant formulas for TMCs in electromagnetic
and weak processes. We include a full analysis of both hadronic and partonic
masses, and trace how these effects appear in the operator product expansion
and the factorized parton model formalism, as well as their limitations when
applied to data in the x->1 limit. We evaluate the numerical effects of TMCs on
various structure functions, and compare fits to data with and without these
corrections.


title:
Regularity of C^{1} smooth surfaces with prescribed p-mean curvature in
  the Heisenberg group

abstract:
  We consider a $C^{1}$ smooth surface with prescribed $p$(or $H$)-mean
curvature in the 3-dimensional Heisenberg group. Assuming only the prescribed
$p$-mean curvature $H\in C^{0},$ we show that any characteristic curve is
$C^{2}$ smooth and its (line) curvature equals $-H$ in the nonsingular
domain$.$ By introducing characteristic coordinates and invoking the jump
formulas along characteristic curves, we can prove that the Legendrian (or
horizontal) normal gains one more derivative. Therefore the seed curves are
$C^{2}$ smooth. We also obtain the uniqueness of characteristic and seed curves
passing through a common point under some mild conditions, respectively. These
results can be applied to more general situations.


title: Compact broadband planar orthomode transducer

abstract:
  We present the design and test results of a compact C-band orthomode
transducer which comprises four rectangular probes orthogonally arranged in a
circular waveguide, designed to work in the WG13 band. Measurements of the
system in the frequency range 4.64 GHz to 7.05 GHz agree very well with
simulation results and show a cross-polarisation level below -58 dB, a return
loss of about -20 dB, and an insertion loss difference of less than 0.18 dB
between the orthogonal polarisation modes across the full waveguide band.


title: A local homology theory for linearly compact modules

abstract:
  We introduce a local homology theory for linearly compact modules which is in
some sense dual to the local cohomology theory of A. Grothendieck. Some basic
properties such as the noetherianness, the vanishing and non-vanishing of local
homology modules of linearly compact modules are proved. A duality theory
between local homology and local cohomology modules of linearly compact modules
is developed by using Matlis duality and Macdonald duality. As consequences of
the duality theorem we obtain some generalizations of well-known results in the
theory of local cohomology for semi-discrete linearly compact modules.


title: Magnetic properties of the Haldane-gap material NENB

abstract:
  Results of magnetization and high-field ESR studies of the new spin-1
Haldane-chain material [Ni(C2H8N2)2NO2](BF4) (NENB) are reported. A definite
signature of the Haldane state in NENB was obtained. From the analysis of the
frequency-field dependence of magnetic excitations in NENB, the
spin-Hamiltonian parameters were calculated, yielding Delta = 17.4 K,
g_parallel = 2.14, D = 7.5 K, and |E| = 0.7 K for the Haldane gap, g factor and
the crystal-field anisotropy constants, respectively. The presence of
fractional S = 1/2 chain-end states, revealed by ESR and magnetization
measurements, is found to be responsible for spin-glass freezing effects. In
addition, extra states in the excitation spectrum of NENB have been observed in
the vicinity of the Haldane gap, which origin is discussed.


title: Graphical Quantum Error-Correcting Codes

abstract:
  We introduce a purely graph-theoretical object, namely the coding clique, to
construct quantum errorcorrecting codes. Almost all quantum codes constructed
so far are stabilizer (additive) codes and the construction of nonadditive
codes, which are potentially more efficient, is not as well understood as that
of stabilizer codes. Our graphical approach provides a unified and classical
way to construct both stabilizer and nonadditive codes. In particular we have
explicitly constructed the optimal ((10,24,3)) code and a family of 1-error
detecting nonadditive codes with the highest encoding rate so far. In the case
of stabilizer codes a thorough search becomes tangible and we have classified
all the extremal stabilizer codes up to 8 qubits.


title:
On scattering of Giant Pulses from the Crab Pulsar: a Scattering
  Function

abstract:
  Simultaneous dual-frequency observations of giant pulses from the Crab pulsar
were performed at the frequencies of 61 and 111 MHz. It is shown that
scattering of giant pulses from the Crab pulsar occurs at thick, and not at
thin screen.


title: Supersonic dislocations observed in a plasma crystal

abstract:
  Experimental results on the dislocation dynamics in a two-dimensional plasma
crystal are presented. Edge dislocations were created in pairs in lattice
locations where the internal shear stress exceeded a threshold and then moved
apart in the glide plane at a speed higher than the sound speed of shear waves,
$C_T$. The experimental system, a plasma crystal, allowed observation of this
process at an atomistic (kinetic) level. The early stage of this process is
identified as a stacking fault. At a later stage, supersonically moving
dislocations generated shear-wave Mach cones.


title: Wakefield Acceleration by Radiation Pressure in Relativistic Shock Waves

abstract:
  A particle acceleration mechanism by radiation pressure of precursor waves in
a relativistic shock is studied. For a relativistic, perpendicular shock with
the upstream bulk Lorentz factor of $\gamma_1 \gg 1$, large amplitude
electromagnetic (light) waves are known to be excited in the shock front due to
the synchrotron maser instability, and those waves can propagate towards
upstream as precursor waves. We find that non-thermal, high energy electrons
and ions can be quickly produced by an action of electrostatic wakefields
generated by the ponderomotive force of the precursor waves. The particles can
be quickly accelerated up to $\epsilon_{\rm max}/\gamma_1 m_e c^2 \sim
\gamma_1$ in the upstream coherent wakefield region, and they can be further
accelerated during the nonlinear stage of the wakefield evolution. The maximum
attainable energy is estimated by $\epsilon_{\rm max}/\gamma_1 m_e c^2 \sim
L_{\rm sys}/(c/\omega_{pe})$, where $L_{\rm sys}$ and $c/\omega_{pe}$ are the
size of an astrophysical object and the electron inertial length, respectively.


title:
A numerical simulation of the evolution and fate of a FRI jet. The case
  of 3C 31

abstract:
  The evolution of FRI jets has been long studied in the framework of the
FRI-FRII dichotomy. In this paper, we test the present theoretical and
observational models via a relativistic numerical simulation of the jets in the
radio galaxy 3C 31. We use the parameters derived from the modelling presented
by \cite{lb02a,lb02b} as input parameters for the simulation of the evolution
of the source, thus assuming that they have not varied over the lifetime of the
source. We simulate about 10 % of the total lifetime of the jets in 3C 31.
Realistic density and pressure gradients for the atmosphere are used. The
simulation includes an equation of state for a two-component relativistic gas
that allows a separate treatment of leptonic and baryonic matter. We compare
our results with the modelling of the observational data of the source. Our
results show that the bow shock evolves self-similarly at a quasi-constant
speed, with slight deceleration by the end of the simulation, in agreement with
recent X-ray observations that show the presence of bow shocks in FRI sources.
The jet expands until it becomes underpressured with respect to the ambient
medium, and then recollimates. Subsequent oscillations around pressure
equilibrium and generation of standing shocks lead to the mass loading and
disruption of the jet flow. We derive an estimate for the minimum age of the
source of $t>1. 10^8 \rm{yrs}$, which may imply continuous activity of 3C 31
since the triggering of its activity. The simulation shows that weak CSS
sources may be the young counterparts of FRIs. We conclude that the observed
properties of the jets in 3C 31 are basically recovered by the standing shock
scenario.


title: Storage and Retrieval of a Squeezed Vacuum

abstract:
  Storage and retrieval of a squeezed vacuum was successfully demonstrated
using electromagnetically induced transparency. 930ns of the squeezed vacuum
pulse was incident on the laser cooled 87Rb atoms with an intense control light
in a coherent state. When the squeezed vacuum pulse was slowed and spatially
compressed in the cold atoms, the control light was switched off. After 3us of
storage, the control light was switched on again and the squeezed vacuum was
retrieved, as was confirmed using the time-domain homodyne method.


title: Inflaton Decay in Supergravity and Gravitino Problem

abstract:
  We have recently shown that, if the inflaton has a nonzero vacuum expectation
value, it generically couples to any matter fields that appear in the
superpotential at the tree level, and to any gauge sectors through anomalies in
the supergravity. Through these processes, the inflaton decays into the
supersymmetry breaking sector, producing many gravitinos. The inflaton also
directly decays into a pair of the gravitinos. Taking account of these
processes, we derive constraints on both inflation models and supersymmetry
breaking scenarios for avoiding overproduction of the gravitinos.


title: Dismantling sparse random graphs

abstract:
  We consider the number of vertices that must be removed from a graph G in
order that the remaining subgraph has no component with more than k vertices.
Our principal observation is that, if G is a sparse random graph or a random
regular graph on n vertices with n tending to infinity, then the number in
question is essentially the same for all values of k such that k tends to
infinity but k=o(n).


title: Leonhard Euler and a q-analogue of the logarithm

abstract:
  We study a q-logarithm which was introduced by Euler and give some of its
properties. This q-logarithm did not get much attention in the recent
literature. We derive basic properties, some of which were already given by
Euler in a 1751-paper and 1734-letter to Daniel Bernoulli. The corresponding
q-analogue of the dilogarithm is introduced. The relation to the values at 1
and 2 of a q-analogue of the zeta function is given. We briefly describe some
other q-logarithms that have appeared in the recent literature.


title:
Remarkable virtual SUSY effects in $W^{\pm}$ production at high energy
  hadron colliders

abstract:
  We present a complete 1-loop study of the electroweak corrections to the
process $ug\to dW^+$ in MSSM and SM.
  The occurrence of a number of remarkable properties in the behavior of the
helicity amplitudes at high energies is stressed, and the crucial role of the
virtual SUSY contributions in establishing them, is emphasized. The approach to
asymptopia of these amplitudes is discussed, comparing the effects of the
logarithmic and constant contributions to the mass suppressed ones, which are
relevant at lower energies. Applying crossing to $ug\to d W^+$, we obtain all
subprocesses needed for the 1-loop electroweak corrections to
$W^\pm$-production at LHC. The SUSY model dependence of such a production is
then studied, and illustrations are given for the transverse $W^{\pm}$ momentum
distribution, as well as the angular distribution in the subprocess center of
mass.


title: Morphology of flows and buoyant bubbles in the Virgo cluster

abstract:
  There is growing evidence that the active galactic nuclei (AGN) associated
with the central elliptical galaxy in clusters of galaxies are playing an
important role in the evolution of the intracluster medium (ICM) and clusters
themselves. We use high resolution three-dimensional simulations to study the
interaction of the cavities created by AGN outflows (bubbles) with the ambient
ICM. The gravitational potential of the cluster is modelled using the observed
temperature and density profiles of the Virgo cluster. We demonstrate the
importance of the hydrodynamical Kutta-Zhukovsky forces associated with the
vortex ring structure of the bubbles, and discuss possible effects of diffusive
processes on their evolution.


title: Ferroelectricity in artificial bicolor oxide superlattices

abstract:
  We report on the growth and properties of high quality bicolor oxide
superlattices, composed of two perovskites out of BaTiO3, CaTiO3, and SrTiO3.
The artificially grown superlattices are structurally unique and have a
macroscopically homogeneous phase, which is not feasible to recreate in bulk
form. By artificial structuring, it is found that the polarization of such
superlattices can be highly increased as compared to pseudo-binary ceramics
with the same overall composition. Such strong enhancement in superlattice is
attributed to newly-developed ionic motions of A-site cations at the
hetero-interfaces due to the interfacial coupling of electrostatic and elastic
interactions, which cannot be found in single phase materials.


title:
On the influence of time and space correlations on the next earthquake
  magnitude

abstract:
  A crucial point in the debate on feasibility of earthquake prediction is the
dependence of an earthquake magnitude from past seismicity. Indeed, whilst
clustering in time and space is widely accepted, much more questionable is the
existence of magnitude correlations. The standard approach generally assumes
that magnitudes are independent and therefore in principle unpredictable. Here
we show the existence of clustering in magnitude: earthquakes occur with higher
probability close in time, space and magnitude to previous events. More
precisely, the next earthquake tends to have a magnitude similar but smaller
than the previous one. A dynamical scaling relation between magnitude, time and
space distances reproduces the complex pattern of magnitude, spatial and
temporal correlations observed in experimental seismic catalogs.


title:
Effective dislocation lines in continuously dislocated crystals. I.
  Material anholonomity

abstract:
  A continuous geometric description of Bravais monocrystals with many
dislocations and secondary point defects created by the distribution of these
dislocations is proposed. Namely, it is distinguished, basing oneself on Kondo
and Kroners Gedanken Experiments for dislocated bodies, an anholonomic triad of
linearly independent vector fields. The triad defines local crystallographic
directions of the defective crystal as well as a continuous counterpart of the
Burgers vector for single dislocations. Next, the influence of secondary point
defects on the distribution of many dislocations is modeled by treating these
local crystallographic directions as well as Burgers circuits as those located
in such a Riemannian material space that becomes an Euclidean 3-manifold when
dislocations are absent. Some consequences of this approach are discussed.


title: Overlap-free words and spectra of matrices

abstract:
  Overlap-free words are words over the binary alphabet $A=\{a, b\}$ that do
not contain factors of the form $xvxvx$, where $x \in A$ and $v \in A^*$. We
analyze the asymptotic growth of the number $u_n$ of overlap-free words of
length $n$ as $ n \to \infty$. We obtain explicit formulas for the minimal and
maximal rates of growth of $u_n$ in terms of spectral characteristics (the
lower spectral radius and the joint spectral radius) of certain sets of
matrices of dimension $20 \times 20$. Using these descriptions we provide new
estimates of the rates of growth that are within 0.4% and $0.03 %$ of their
exact values. The best previously known bounds were within 11% and 3%
respectively. We then prove that the value of $u_n$ actually has the same rate
of growth for ``almost all'' natural numbers $n$. This ``average'' growth is
distinct from the maximal and minimal rates and can also be expressed in terms
of a spectral quantity (the Lyapunov exponent). We use this expression to
estimate it. In order to obtain our estimates, we introduce new algorithms to
compute spectral characteristics of sets of matrices. These algorithms can be
used in other contexts and are of independent interest.


title:
Numerical Simulations of Equatorially-Asymmetric Magnetized Supernovae:
  Formation of Magnetars and Their Kicks

abstract:
  A series of numerical simulations on magnetorotational core-collapse
supernovae are carried out. Dipole-like configurations which are offset
northward are assumed for the initially strong magnetic fields together with
rapid differential rotations. Aims of our study are to investigate effects of
the offset magnetic field on magnetar kicks and on supernova dynamics. Note
that we study a regime where the proto-neutron star formed after collapse has a
large magnetic field strength approaching that of a ``magnetar'', a highly
magnetized slowly rotating neutron star. As a result, equatorially-asymmetric
explosions occur with a formation of the bipolar jets. Resultant magnetar's
kick velocities are $\sim 300-1000$ km s$^{-1}$. We find that the acceleration
is mainly due to the magnetic pressure while the somewhat weaker magnetic
tension works toward the opposite direction, which is due to stronger magnetic
field in the northern hemisphere. Noted that observations of magnetar's proper
motions are very scarce, our results supply a prediction for future
observations. Namely, magnetars possibly have large kick velocities, several
hundred km s$^{-1}$, as ordinary neutron stars do, and in an extreme case they
could have those up to 1000 km s$^{-1}$.


title: Dynamics of buoyant bubbles in clusters of galaxies

abstract:
  We present a phenomenological model of the dynamics of buoyant bubbles in the
atmosphere of a cluster of galaxies. The derived equations describe velocity,
size, mass, temperature and density of the buoyant bubbles as functions of time
based on several simple approximations. The constructed model is then used to
interpret results of a numerical experiment of heating of the cluster core with
buoyant bubbles in a hydrodynamical approximation (i.e. in the absence of
magnetic fields, viscosity, and thermal diffusion). Based on the model
parameters we discuss possible limitations of the numerical treatment of the
problem, and highlight the main physical processes that govern the dynamics of
bubbles in the intracluster medium.


title: Stellar molecular jets traced by maser emission

abstract:
  Highly collimated jets found in AGB and post-AGB stars are expected to play
an important role for shaping planetary nebulae. Recent VLBI observations of
H2O maser sources have revealed that some of the spatio-kinematical structures
of H2O maser sources exhibit stellar jets with extremely spatially and
kinematically high collimation. Such stellar H2O maser jets, so-called "water
fountain" sources, have been identified in about 10 sources to date. Here we
review recent VLBI observations and relevant observational results of the water
fountain sources. They have revealed a typical dynamical age and the detailed
kinematical structures of the water fountains, possibility of the existence of
"equatorial flows", and the evolutionary status of the host stars. The location
and kinematics of one of the water fountain sources in the Galaxy is also
revealed and shown here.


title:
Effective dislocation lines in continuously dislocated crystals. II.
  Congruences of effective dislocations

abstract:
  The notion of a congruence of effective dislocation lines endowed with the
nonvanishing local Burgers vector is introduced. Particularly, the class of
congruences of principal Volterra-type effective dislocation lines associated
with the dislocation densities (tensorial as well as scalar) is distinguished
in order to investigate the geometry of continuized defective crystals in terms
of these densities. It is shown that effective dislocation lines can be endowed
with the dislocation line tension and with a finite self-energy.


title: Symplectically aspherical manifolds

abstract:
  This is a survey article on symplectically aspherical manifolds. The paper
contains a discussion on constructions of symplectically aspherical manifolds,
their topological properties and the role of this class in symplectic topology.
Research perspectives are discussed.


title: Molecular motors: design, mechanism and control

abstract:
  Biological functions in each animal cell depend on coordinated operations of
a wide variety of molecular motors. Some of the these motors transport cargo to
their respective destinations whereas some others are mobile workshops which
synthesize macromolecules while moving on their tracks. Some other motors are
designed to function as packers and movers. All these motors require input
energy for performing their mechanical works and operate under conditions far
from thermodynamic equilibrium. The typical size of these motors and the forces
they generate are of the order of nano-meters and pico-Newtons, respectively.
They are subjected to random bombardments by the molecules of the surrounding
aqueous medium and, therefore, follow noisy trajectories. Because of their
small inertia, their movements in the viscous intracellular space exhibits
features that are characteristics of hydrodynamics at low Reynold's number. In
this article we discuss how theoretical modeling and computer simulations of
these machines by physicists are providing insight into their mechanisms which
engineers can exploit to design and control artificial nano-motors.

categories: physics.bio-ph cond-mat.stat-mech physics.pop-ph q-bio.SC


title:
Campbell equilibrium equation and pseudo-likelihood estimation for
  non-hereditary Gibbs point processes

abstract:
  In this paper, we study Gibbs point processes involving a hardcore
interaction which is not necessarily hereditary. We first extend the famous
Campbell equilibrium equation, initially proposed by Nguyen and Zessin [Math.
Nachr. 88 (1979) 105--115], to the non-hereditary setting and consequently
introduce the new concept of removable points. A modified version of the
pseudo-likelihood estimator is then proposed, which involves these removable
points. We consider the following two-step estimation procedure: first estimate
the hardcore parameter, then estimate the smooth interaction parameter by
pseudo-likelihood, where the hardcore parameter estimator is plugged in. We
prove the consistency of this procedure in both the hereditary and
non-hereditary settings.


title:
Effective dislocation lines in continuously dislocated crystals. III.
  Kinematics

abstract:
  A class of congruences of principal Volterra-type effective dislocation lines
associated with a dislocation density tensor is distinguished in order to
investigate the kinematics of continuized defective crystals in terms of their
dislocation densities (tensorial as well as scalar). Moreover, it shown, basing
oneself on a formula defining the mean curvature of glide surfaces for
principal edge effective dislocation lines, that the considered kinematics of
continuized defective crystals is consistent with some relations appearing in
the physical theory of plasticity (e.g. with the Orowan-type kinematic
relations and with the treatment of shear stresses as driving stresses of
moving dislocations).


title: Electron energy spectrum and the Berry phase in graphite bilayer

abstract:
  We emphasize that there exist four Dirac-type points in the electron-energy
spectrum of a graphite bilayer near the point K of its Brillouin zone. One of
the Dirac points is at the point K, and three Dirac points lie nearby. Each of
these three points generates the Berry phase $\pi$, while the Dirac point at K
gives the phase $-\pi$. It is these four points that determine the Berry phase
in the bilayer. If an electron orbit surrounds all these points, the Berry
phase is equal to $2\pi$.


title:
Reproducing the assembly of massive galaxies within the hierarchical
  cosmogony

abstract:
  In order to gain insight into the physical mechanisms leading to the
formation of stars and their assembly in galaxies, we compare the predictions
of the MOdel for the Rise of GAlaxies aNd Active nuclei (MORGANA) to the
properties of K- and 850 micron-selected galaxies (such as number counts,
redshift distributions and luminosity functions) by combining MORGANA with the
spectrophotometric model GRASIL. We find that it is possible to reproduce the
K- and 850 micron-band datasets at the same time and with a standard Salpeter
IMF, and ascribe this success to our improved modeling of cooling in DM halos.
We then predict that massively star-forming discs are common at z~2 and
dominate the star-formation rate, but most of them merge with other galaxies
within ~100 Myr. Our preferred model produces an overabundance of bright
galaxies at z<1; this overabundance might be connected to the build-up of the
diffuse stellar component in galaxy clusters, as suggested by Monaco et al.
(2006), but a naive implementation of the mechanism suggested in that paper
does not produce a sufficient slow-down of the evolution of these objects.
Moreover, our model over-predicts the number of 10^{10}-10^{11} M_sun galaxies
at z~1; this is a common behavior of theoretical models as shown by Fontana et
al. (2006). These findings show that, while the overall build-up of the stellar
mass is correctly reproduced by galaxy formation models, the ``downsizing''
trend of galaxies is not fully reproduced yet. This hints to some missing
feedback mechanism in order to reproduce at the same time the formation of both
the massive and the small galaxies.


title:
New twist field couplings from the partition function for multiply
  wrapped D-branes

abstract:
  We consider toroidal compactifications of bosonic string theory with
particular regard to the phases (cocycles) necessary for a consistent
definition of the vertex operators, the boundary states and the T-duality
rules. We use these ingredients to compute the planar multi-loop partition
function describing the interaction among magnetized or intersecting D-branes,
also in presence of open string moduli. It turns out that unitarity in the open
string channel crucially depends on the presence of the cocycles. We then focus
on the 2-loop case and study the degeneration limit where this partition
function is directly related to the tree-level 3-point correlators between
twist fields. These correlators represent the main ingredient in the
computation of Yukawa couplings and other terms in the effective action for
D-brane phenomenological models. By factorizing the 2-loop partition function
we are able to compute the 3-point couplings for abelian twist fields on
generic non-factorized tori, thus generalizing previous expressions valid for
the 2-torus.


title: Initial Helioseismic Observations by Hinode/SOT

abstract:
  Results from initial helioseismic observations by Solar Optical Telescope
onboard Hinode are reported. It has been demonstrated that intensity
oscillation data from Broadband Filter Imager can be used for various
helioseismic analyses. The k-omega power spectra, as well as corresponding
time-distance cross-correlation function that promises high-resolution
time-distance analysis below 6-Mm travelling distance, were obtained for G-band
and CaII-H data. Subsurface supergranular patterns have been observed from our
first time-distance analysis. The results show that the solar oscillation
spectrum is extended to much higher frequencies and wavenumbers, and the
time-distance diagram is extended to much shorter travel distances and times
than they were observed before, thus revealing great potential for
high-resolution helioseismic observations from Hinode.


title: Pion-Nucleon Distribution Amplitudes

abstract:
  This is a short presentation of the results for the pion-nucleon distribution
amplitudes which are expressed in terms of the nucleon distribution amplitudes
with the help of current algebra. Everything is considered to be at threshold.


title: SiPM Development for Astroparticle Physics Applications

abstract:
  The SiPM is a novel solid state photodetector which can be operated in the
single photon counting mode. It has excellent features, such as high quantum
efficiency, good charge resolution, fast response, very compact size, high gain
of 106, very low power consumption, immunity to the magnetic field and low bias
voltage (30-70V). Drawbacks of this device currently are a large dark current,
crosstalk between micropixels and relatively low sensitivity to UV and blue
light. In the last few years, we have developed large size SiPMs (9 mm^2 and 25
mm^2) for applications in the imaging atmospheric Cherenkov telescopes, MAGIC
and CTA, and in the space-borne fluorescence telescope EUSO. The current status
of the SiPM development by MPI and MEPhI will be presented.


title: Dynamical response functions in the quantum Ising chain with a boundary

abstract:
  We determine dynamical response functions $<{\cal O}^\dagger(t,x_1){\cal
O}(0,x_2)>$ in the scaling limit of the quantum Ising chain on the half line in
the presence of a boundary magnetic field. Using a spectral representation in
terms of infinite volume form factors and a boundary state, we derive an
expansion for the correlator that is found to be rapidly convergent as long as
$|\frac{x_1+x_2}{\xi}|\agt 0.2$ where $\xi$ is the correlation length. At
sufficiently late times we observe oscillatory behaviour of the correlations
arbitrarily far away from the boundary. We investigate the effects of the
boundary bound state that is present for a range of boundary magnetic fields.


title: Shaping the waveform of entangled photons

abstract:
  We demonstrate experimentally the tunable control of the joint spectrum, i.e.
waveform and degree of frequency correlations, of paired photons generated in
spontaneous parametric downconversion. This control is mediated by the spatial
shape of the pump beam in a type-I noncollinear configuration. We discuss the
applicability of this technique to other sources of frequency entangled
photons, such as electromagnetically induced Raman transitions.


title: Discovery of a galactic wind in the central region of M100

abstract:
  We report the discovery of a galactic wind in the central region of the
galaxy M100. This result is based on a careful 2D spectroscopic study performed
on observations made with the fibre system INTEGRAL on the WHT. The primary
evidence of the wind is the presence of blueshifted interstellar NaD absorption
lines. The velocity field of the absorbers show a clear rotation pattern but
globally blueshifted ($\sim$ -115 km/s) with respect to the systemic velocity
of the galaxy.
  The emission lines also present a blueward component arising from the ionized
gas phase of the galactic wind. The velocity field of the ionized gas wind
component shows no evidences of rotation but exhibits a pattern that can be
interpreted in terms of the projection of an outflowing cone or shell. The wind
component has [NII]/H$\alpha$ ratios of about 1.8, typical of shock ionization.
The ionized component of the wind can be identified with an expanding shell of
shocked gas, and the neutral component with disk gas entrained in the wind at
the interface of the expanding shell with the galactic ISM. The galactic wind
seems to be driven uniquely by the nuclear starburst. Our analysis indicates
that a non negligible fraction of the wind material might escape to the IGM. In
this case, if the wind detected in M100 were representative of similar
phenomena in other galaxies with low to moderate activity, the current
estimates of metal and dust content of the IGM might be drastically
underestimated.


title: A Bohr's Semiclassical Model of the Black Hole Thermodynamics

abstract:
  We propose a simple procedure for evaluating the main thermodynamical
attributes of a Schwarzschild's black hole: Bekenstein-Hawking entropy,
Hawking's temperature and Bekenstein's quantization of the surface area. We
make use of the condition that the circumference of a great circle on the black
hole horizon contains finite number of the corresponding reduced Compton's
wavelength. It is essentially analogous to Bohr's quantization postulate in
Bohr's atomic model interpreted by de Broglie's relation. We present black hole
radiation in the form conceptually analogous to Bohr's postulate on the photon
emission by discrete quantum jump of the electron within the Old quantum
theory. It enables us, in accordance with Heisenberg's uncertainty relation and
Bohr's correspondence principle, to make a rough estimate of the time interval
for black hole evaporation, which turns out very close to time interval
predicted by the standard Hawking's theory. Our calculations confirm
Bekenstein's semiclassical result for the energy quantization, in variance with
Frasca's (2005) calculations. Finally we speculate about the possible
source-energy distribution within the black hole horizon.


title: Enabling electronic prognostics using thermal data

abstract:
  Prognostics is a process of assessing the extent of deviation or degradation
of a product from its expected normal operating condition, and then, based on
continuous monitoring, predicting the future reliability of the product. By
being able to determine when a product will fail, procedures can be developed
to provide advanced warning of failures, optimize maintenance, reduce life
cycle costs, and improve the design, qualification and logistical support of
fielded and future systems. In the case of electronics, the reliability is
often influenced by thermal loads, in the form of steady-state temperatures,
power cycles, temperature gradients, ramp rates, and dwell times. If one can
continuously monitor the thermal loads, in-situ, this data can be used in
conjunction with precursor reasoning algorithms and stress-and-damage models to
enable prognostics. This paper discusses approaches to enable electronic
prognostics and provides a case study of prognostics using thermal data.


abstract:
  Thermal measurement and modeling of multi-die packages became a hot topic
recently in different fields like RAM chip packaging or LEDs / LED assemblies,
resulting in vertical (stacked) and lateral arrangement. In our present study
we show results for a mixed arrangement: an opto-coupler device has been
investigated with 4 chips in lateral as well as vertical arrangement. In this
paper we give an overview of measurement and modeling techniques and results
for stacked and MCM structures, describe our present measurement results
together with our structure function based methodology of validating the
detailed model of the package being studied. Also, we show how to derive
junction-to-pin thermal resistances with a technique using structure functions.


title: Electrical, thermal and optical characterization of power LED assemblies

abstract:
  Besides their electrical properties the optical parameters of LEDs also
depend on junction temperature. For this reason thermal characterization and
thermal management play important role in case of power LEDs, necessitating
both physical measurements and simulation tools. The focus of this paper is a
combined electrical, thermal and optical characterization of power LED
assemblies. In terms of simulation a method for board-level electro-thermal
simulation is presented, for measurements a combined thermal and radiometric
characterization system of power LEDs and LED assemblies is discussed.
Comparison of measurement and simulation results is presented in a case study.


title: Dynamics of hadron strong production and decay

abstract:
  We generalize results of lattice QCD to determine the spin-dependent
symmetries and factorization properties of meson production in OZI allowed
processes. This explains some conjectures previously made in the literature
about axial meson decays and gives predictions for exclusive decays of vector
charmonia, including ways of establishing the structure of Y(4260) and Y(4325)
from their S-wave decays. Factorization gives a selection rule which forbids
$e^+e^- \to D^* D_2$ near threshold with the tensor meson in helicity 2. The
relations among amplitudes for double charmonia production $\e^+e^-\to
\psi\chi_{0,1,2}$ are expected to differ from the analagous relations among
light flavour production such as $\e^+e^-\to \omega f_{0,1,2}$.


title: Thermal Transient Characterization of Packaged Thin Film Microcoolers

abstract:
  A network identification by deconvolution (NID) method is applied to the
thermal transient response of packaged and unpackaged microcoolers. A thin film
resistor on top of the device is used as the heat source and the temperature
sensor. The package and the bonding thermal resistances can be easily
identified by comparing structure functions. High-speed coplanar probes are
used to achieve a short time resolution of roughly 100ns in the transient
temperature response. This is used to separate the thermal properties of the
thin film from the substrate. The obtained thermal resistances of the buffer
layer and Silicon substrate are consistent with the theoretical calculations.
In order to estimate the superlattice thermal resistance and separate it from
the thin SiNx layer deposited underneath the thin film resistive sensor, an
order of magnitude faster thermal transient response is needed.


title: Dynamic Thermal Analysis of a Power Amplifier

abstract:
  This paper presents dynamic thermal analyses of a power amplifier. All the
investigations are based on the transient junction temperature measurements
performed during the circuit cooling process. The presented results include the
cooling curves, the structure functions, the thermal time constant distribution
and the Nyquist plot of the thermal impedance. The experiments carried out
demonstrated the influence of the contact resistance and the position of the
entire cooling assembly on the obtained results.


title:
Thermal Properties of High Power Laser Bars Investigated by Spatially
  Resolved Thermoreflectance Spectroscopy

abstract:
  In this work we present results of the analysis of thermal properties of
high-power laser bars obtained by spatially resolved thermoreflectance (TR)
spectroscopy. Thermoreflectance is a modulation technique relying on periodic
facet temperature modulation induced by pulsed current supply of the laser. The
periodic temperature change of the laser induces variation of the refractive
index and consequently modulates probe beam reflectivity. The technique has a
spatial resolution of about ~1 $\mu$m and can be used for temperature mapping
over 300 $\mu$m x 300 $\mu$m area. Information obtained in these experiments
provide an insight into thermal processes occurring at devices' facets and
consequently lead to increased reliability and substantially longer lifetimes
of such structures.


title: Quantum phase slips in a confined geometry

abstract:
  We consider tunneling of vortices across a superconducting film that is both
narrow and short (and connected to bulk superconducting leads at the ends). We
find that in the superconducting state the resistance, at low values of the
temperature (T) and current, does not follow the power-law dependence on T
characteristic of longer samples but is exponential in 1/T. The coefficient of
1/T in the exponent depends on the length or, equivalently, the total
normal-state resistance of the sample. These conclusions persist in the
one-dimensional limit, which is similar to the problem of quantum phase slips
in an ultra-narrow short wire.


title:
Contactless Thermal Characterization Method of PCB-s Using Different IR
  Sensor Arrays

abstract:
  In this paper the methodology and the results of a quasi real-time thermal
characterization tool and method for the temperature mapping of circuits and
boards based on sensing the infrared radiation will be introduced. With the
proposed method the IR radiation-distribution of boards from the close
proximity of the sensor card is monitored in quasi real-time. The proposed
method is enabling in situ IR measurement among operating cards of a system
e.g. in a rack, enabling the immediate detection of potential hot spots in the
system. . The elevated temperature encountered in different packaged electronic
devices, like digital processors, high power amplifier, high power switches,
etc., demands the application of careful temperature-aware design methodologies
and the electro-thermal simulations of PCBs. The results of different
electro-thermal simulations and modeling in most of the cases give good
approximating results and consider the coupled effects of the real surroundings
of these cards and other dissipation elements in an operating system. However
the simulation time may take hours, and different systems, different
surroundings should be simulated again and again. In our expectation, by using
contactless temperature measurement procedure the heat distribution and the
places of high dissipation elements on an operating PCB board (PCI or AGP cards
in a rack-house of a PC) can be measured and localized in a dense rack system,
where only a thin measuring board can be inserted between the cards during
operation.


title: TherMos3, a tool for 3D electrothermal simulation of Smart Power Mosfets

abstract:
  In this paper we report on a novel simulation tool designed for the 3D
coupled electro-thermal simulation of Smart Power Mosfets, that is a tool
capable of taking into account not only the electrical (and thermal) behaviour
of the power device but also the different driving strategies as they are
imposed by a control logic circuit which usually resides on the same chip. The
simulator is fully developed under Matlab and solves, self consistently, the 3D
heat equation with proper boundary conditions and heat sources. An adaptive
meshing algorithm based on temperature gradients and an optimized time stepping
strategy have also been developed to reduce computational load and speed up
simulation time without loosing accuracy. To validate this approach, simulator
results are finally compared to experimental data obtained on a commercial
Smart Power device used in automotive applications.


title: Performance of the Pierre Auger Observatory Surface Detector

abstract:
  The Surface Detector of the Pierre Auger Observatory will consist of 1600
water Cherenkov tanks sampling ground particles of air showers produced by
energetic cosmic rays. The arrival times are obtained from GPS and power is
provided by solar panels. The construction of the array is nearly completed and
a large number of detectors has been operational for more than three years. In
this paper the performance of different components of the detectors are
discussed. The accuracy of the signal measurement and the trigger stability are
presented. The performance of the solar power system and other hardware, as
well as the water purity and its long-term stability are discussed.


title: Monte Carlo Simulations for NLO Chargino Production at the ILC

abstract:
  We present an extension of the Monte Carlo Event Generator Whizard which
includes chargino production at the ILC at NLO. We include photons using both a
fixed order and a resummation approach. In the latter, leading higher order
corrections are automatically included. We present results for cross sections
and event generation for both methods.


title: Cold Atoms and Molecules in Self-Assembled Dipolar Lattices

abstract:
  We study the realization of lattice models, where cold atoms and molecules
move as extra particles in a dipolar crystal of trapped polar molecules. The
crystal is a self-assembled floating mesoscopic lattice structure with quantum
dynamics given by phonons. We show that within an experimentally accessible
parameter regime extended Hubbard models with tunable long-range
phonon-mediated interactions describe the effective dynamics of dressed
particles.


title: Tropical analysis of plurisubharmonic singularities

abstract:
  Some results on singularities of plurisubharmonic functions are put into the
context of tropical mathematics.


title:
On detecting CP violation in a single neutrino oscillation channel at
  very long baselines

abstract:
  We propose a way of detecting CP violation in a single neutrino oscillation
channel at very long baselines (on the order of several thousands of
kilometers), given precise knowledge of the smallest mass-squared difference.
It is shown that CP violation can be characterized by a shift in $L/E$ of the
peak oscillation in the $\nu_e$--$\nu_\mu$ appearance channel, both in vacuum
and in matter. In fact, matter effects enhance the shift at a fixed energy. We
consider the case in which sub-GeV neutrinos are measured with varying baseline
and also the case of a fixed baseline. For the varied baseline, accurate
knowledge of the absolute neutrino flux would not be necessary; however,
neutrinos must be distinguishable from antineutrinos. For the fixed baseline,
it is shown that CP violation can be distinguished if the mixing angle
$\theta_{13}$ were known.


title: One-loop energy-momentum tensor in QED with electric-like background

abstract:
  We have obtained nonperturbative one-loop expressions for the mean
energy-momentum tensor and current density of Dirac's field on a constant
electric-like background. One of the goals of this calculation is to give a
consistent description of back-reaction in such a theory. Two cases of initial
states are considered: the vacuum state and the thermal equilibrium state.
First, we perform calculations for the vacuum initial state. In the obtained
expressions, we separate the contributions due to particle creation and vacuum
polarization. The latter contributions are related to the Heisenberg-Euler
Lagrangian. Then, we study the case of the thermal initial state. Here, we
separate the contributions due to particle creation, vacuum polarization, and
the contributions due to the work of the external field on the particles at the
initial state. All these contributions are studied in detail, in different
regimes of weak and strong fields and low and high temperatures. The obtained
results allow us to establish restrictions on the electric field and its
duration under which QED with a strong constant electric field is consistent.
Under such restrictions, one can neglect the back-reaction of particles created
by the electric field. Some of the obtained results generalize the calculations
of Heisenberg-Euler for energy density to the case of arbitrary strong electric
fields.


title:
Nonlinear mean field Fokker-Planck equations. Application to the
  chemotaxis of biological populations

abstract:
  We study a general class of nonlinear mean field Fokker-Planck equations in
relation with an effective generalized thermodynamical formalism. We show that
these equations describe several physical systems such as: chemotaxis of
bacterial populations, Bose-Einstein condensation in the canonical ensemble,
porous media, generalized Cahn-Hilliard equations, Kuramoto model, BMF model,
Burgers equation, Smoluchowski-Poisson system for self-gravitating Brownian
particles, Debye-Huckel theory of electrolytes, two-dimensional turbulence...
In particular, we show that nonlinear mean field Fokker-Planck equations can
provide generalized Keller-Segel models describing the chemotaxis of biological
populations. As an example, we introduce a new model of chemotaxis
incorporating both effects of anomalous diffusion and exclusion principle
(volume filling). Therefore, the notion of generalized thermodynamics can have
applications for concrete physical systems. We also consider nonlinear mean
field Fokker-Planck equations in phase space and show the passage from the
generalized Kramers equation to the generalized Smoluchowski equation in a
strong friction limit. Our formalism is simple and illustrated by several
explicit examples corresponding to Boltzmann, Tsallis and Fermi-Dirac entropies
among others.


title: Advanced Compact Thermal Modeling by using VHDL-AMS

abstract:
  This paper presents an improved methodology to generate Compact Thermal
Models "CTMs" by using (VHDL-AMS) modeling language. This methodology makes it
possible to have Boundary Conditions Independent "BCI" CTMs for multi chip
components and systems while taking into account the nonlinear thermal
conductivity of semiconductors and other materials.


title:
The Hot-Spot Phenomenon and its Countermeasures in Bipolar Power
  Transistors by Analytical Electro-Thermal Simulation

abstract:
  This communication deals with a theoretical study of the hot spot onset (HSO)
in cellular bipolar power transistors. This well-known phenomenon consists of a
current crowding within few cells occurring for high power conditions, which
significantly decreases the forward safe operating area (FSOA) of the device.
The study was performed on a virtual sample by means of a fast, fully
analytical electro-thermal simulator operating in the steady state regime and
under the condition of imposed input base current. The purpose was to study the
dependence of the phenomenon on several thermal and geometrical factors and to
test suitable countermeasures able to impinge this phenomenon at higher biases
or to completely eliminate it. The power threshold of HSO and its localization
within the silicon die were observed as a function of the electrical bias
conditions as for instance the collector voltage, the equivalent thermal
resistance of the assembling structure underlying the silicon die, the value of
the ballasting resistances purposely added in the emitter metal
interconnections and the thickness of the copper heat spreader placed on the
die top just to the aim of making more uniform the temperature of the silicon
surface.


title: Ground-state structure of the hydrogen double vacancy on Pd(111)

abstract:
  We determine the ground-state structure of a double vacancy in a hydrogen
monolayer on the Pd(111) surface. We represent the double vacancy as a triple
vacancy containing one additional hydrogen atom. The potential-energy surface
for a hydrogen atom moving in the triple vacancy is obtained by
density-functional theory, and the wave function of the fully quantum hydrogen
atom is obtained by solving the Schr\"odinger equation. We find that an H atom
in a divacancy defect experiences significant quantum effects, and that the
ground-state wave function is centered at the hcp site rather than the fcc site
normally occupied by H atoms on Pd(111). Our results agree well with scanning
tunneling microscopy images.


title:
Dynamical Instability of Laminar Axisymmetric Flow of Perfect Fluid with
  Stratification

abstract:
  The instability of non-homoentropic axisymmetric flow of perfect fluid with
respect to non-axisymmetric infinitesimal perturbations was investigated by
numerical integration of hydrodynamical differential equations in
two-dimensional approximation. The non-trivial influence of entropy gradient on
unstable sound and surface gravity waves was revealed. In particular, both
decrease and growth of entropy against the direction of effective gravitational
acceleration $g_{eff}$ give rise to growing surface gravity modes which are
stable with the same parameters in the case of homoentropic flow. At the same
time increment of sound modes either grows monotonically while the rate of
entropy decrease against $g_{eff}$ gets higher or vanishes at some values of
positive and negative entropy gradient in the basic flow. The calculations have
showed also that growing internal gravity modes appear only in the flow
unstable to axisymmetric perturbations. At last, the analysis of boundary
problem with free boundaries uncovered that's incorrect to set the entropy
distribution according to polytropic law with polytropic index different from
adiabatic value, since in this case perturbations don't satisfy the free
boundary conditions.


title: Thermal Benchmark and Power Benchmark Software

abstract:
  Power consumption and heat dissipation become key elements in the field of
high-end integrated circuits, especially those used in mobile and high-speed
applications, due to their increase of transistor count and clock frequencies.
Dynamic thermal management strategies have been proposed and implemented in
order to mitigate heat dissipation. However, there is a lack of a tool that can
be used to evaluate DTM strategies and thermal response of real life systems.
Therefore, in this paper we introduce and define the concepts of thermal
benchmark software and power benchmark software as a software application for
run-time system level thermal and power characterization


title:
Quantitative 3w-Scanning Thermal Microscopy: Modelling the AC/DC
  coupling and the sample heat conduction

abstract:
  A way to increase the Scanning Thermal Microscope (SThM) sensitivity in the
harmonic 3w mode is to heat the probe with an AC current sufficiently high to
generate a coupling between the AC and the DC signals. We detail in this paper
how to properly take into account this coupling with a Wollaston-probe SThM. We
also show how to link correctly the thermal conductivity to the thermal
conductance measured by the SThM.


title: Design issues of a variable thermal resistance

abstract:
  Some years ago we have proposed a thermal mount with electronically variable
thermal resistance [1]. In this earlier work the feasibility of such a
structure has been demonstrated. Now we intend to realize this mount in a
maturated form, suitable to the everyday use in the practice of package thermal
qualification and modeling. The design of such a device raises a number of new
questions and problems. The present paper is dealing with these problems and
the possible solutions.


abstract:
  Spacelike Willmore surfaces in 4-dimensional Lorentzian space forms, a topic
in Lorentzian conformal geometry which parallels the theory of Willmore
surfaces in $S^4$, are studied in this paper. We define two kinds of transforms
for such a surface, which produce the so-called left/right polar surfaces and
the adjoint surfaces. These new surfaces are again conformal Willmore surfaces.
For them holds interesting duality theorem. As an application spacelike
Willmore 2-spheres are classified. Finally we construct a family of homogeneous
spacelike Willmore tori.


title: Matching of correlators in AdS_3/CFT_2

abstract:
  Recently exact agreement has been found between three-point correlators of
chiral operators computed in string theory on AdS_3 x S^3 x T^4 with NS-NS flux
and those computed in the symmetric orbifold CFT. However, it has also been
shown that these correlators disagree with those computed in supergravity,
under any identification of single particle operators which respects the
symmetries. In this note we resolve this disagreement: the key point is that
mixings with multi-particle operators are not suppressed even at large N in
extremal correlators. Allowing for such mixings, orbifold/string theory
operators and supergravity operators can be matched such that both non-extremal
and extremal three point functions agree, giving further evidence for the
non-renormalization of the chiral ring.