title: Local behavior of p-harmonic Green's functions in metric spaces

abstract:
  We describe the behavior of p-harmonic Green's functions near a singularity
in metric measure spaces equipped with a doubling measure and supporting a
Poincar\'e inequality.


title:
Parameter-space correlations of the optimal statistic for continuous
  gravitational-wave detection

abstract:
  The phase parameters of matched-filtering searches for continuous
gravitational-wave signals are sky position, frequency and frequency
time-derivatives. The space of these parameters features strong global
correlations in the optimal detection statistic. For observation times smaller
than one year, the orbital motion of the Earth leads to a family of
global-correlation equations which describes the "global maximum structure" of
the detection statistic. The solution to each of these equations is a different
hypersurface in parameter space. The expected detection statistic is maximal at
the intersection of these hypersurfaces. The global maximum structure of the
detection statistic from stationary instrumental-noise artifacts is also
described by the global-correlation equations. This permits the construction of
a veto method which excludes false candidate events.


title: Heavy Fermion Quantum Criticality

abstract:
  During the last few years, investigations of Rare-Earth materials have made
clear that not only the heavy fermion phase in these systems provides
interesting physics, but the quantum criticality where such a phase dies
exhibits novel phase transition physics not fully understood. Moreover,
attempts to study the critical point numerically face the infamous fermion sign
problem, which limits their accuracy. Effective action techniques and
Callan-Symanzik equations have been very popular in high energy physics, where
they enjoy a good record of success. Yet, they have been little exploited for
fermionic systems in condensed matter physics. In this work, we apply the RG
effective action and Callan-Symanzik techiques to the heavy fermion problem. We
write for the first time the effective action describing the low energy physics
of the system. The f-fermions are replaced by a dynamical scalar field whose
nonzero expected value corresponds to the heavy fermion phase. This removes the
fermion sign problem, making the effective action amenable to numerical studies
as the effective theory is bosonic. Renormalization group studies of the
effective action can be performed to extract approximations to nonperturbative
effects at the transition. By performing one-loop renormalizations, resummed
via Callan-Symanzik methods, we describe the heavy fermion criticality and
predict the heavy fermion critical dynamical susceptibility and critical
specific heat. The specific heat coefficient exponent we obtain (0.39) is in
excellent agreement with the experimental result at low temperatures (0.4).


title: Looking the void in the eyes - the kSZ effect in LTB models

abstract:
  As an alternative explanation of the dimming of distant supernovae it has
recently been advocated that we live in a special place in the Universe near
the centre of a large void described by a Lemaitre-Tolman-Bondi (LTB) metric.
The Universe is no longer homogeneous and isotropic and the apparent late time
acceleration is actually a consequence of spatial gradients in the metric. If
we did not live close to the centre of the void, we would have observed a
Cosmic Microwave Background (CMB) dipole much larger than that allowed by
observations. Hence, until now it has been argued, for the model to be
consistent with observations, that by coincidence we happen to live very close
to the centre of the void or we are moving towards it. However, even if we are
at the centre of the void, we can observe distant galaxy clusters, which are
off-centre. In their frame of reference there should be a large CMB dipole,
which manifests itself observationally for us as a kinematic Sunyaev-Zeldovich
(kSZ) effect. kSZ observations give far stronger constraints on the LTB model
compared to other observational probes such as Type Ia Supernovae, the CMB, and
baryon acoustic oscillations. We show that current observations of only 9
clusters with large error bars already rule out LTB models with void sizes
greater than approximately 1.5 Gpc and a significant underdensity, and that
near future kSZ surveys like the Atacama Cosmology Telescope, South Pole
Telescope, APEX telescope, or the Planck satellite will be able to strongly
rule out or confirm LTB models with giga parsec sized voids. On the other hand,
if the LTB model is confirmed by observations, a kSZ survey gives a unique
possibility of directly reconstructing the expansion rate and underdensity
profile of the void.


title:
Effective mass suppression in dilute, spin-polarized two-dimensional
  electron systems

abstract:
  We report effective mass (m*) measurements, via analyzing the temperature
dependence of the Shubnikov-de Haas oscillations, for dilute, interacting,
two-dimensional electron systems (2DESs) occupying a single conduction-band
valley in AlAs quantum wells. When the 2DES is partially spin-polarized, m* is
larger than its band value, consistent with previous results on various 2DESs.
However, as we fully spin polarize the 2DES by subjecting it to strong parallel
magnetic fields, m* is unexpectedly suppressed and falls even below the band
mass.


title:
Revealing dark matter substructure with anisotropies in the diffuse
  gamma-ray background

abstract:
  The majority of gamma-ray emission from Galactic dark matter annihilation is
likely to be detected as a contribution to the diffuse gamma-ray background. I
show that dark matter substructure in the halo of the Galaxy induces
characteristic anisotropies in the diffuse background that could be used to
determine the small-scale dark matter distribution. I calculate the angular
power spectrum of the emission from dark matter substructure for several models
of the subhalo population, and show that features in the power spectrum can be
used to infer the presence of substructure. The shape of the power spectrum is
largely unaffected by the subhalo radial distribution and mass function, and
for many scenarios I find that a measurement of the angular power spectrum by
Fermi will be able to constrain the abundance of substructure. An anti-biased
subhalo radial distribution is shown to produce emission that differs
significantly in intensity and large-scale angular dependence from that of a
subhalo distribution which traces the smooth dark matter halo, potentially
impacting the detectability of the dark matter signal for a variety of targets
and methods.


title:
The geometry of unitary 2-representations of finite groups and their
  2-characters

abstract:
  Motivated by topological quantum field theory, we investigate the geometric
aspects of unitary 2-representations of finite groups on 2-Hilbert spaces, and
their 2-characters. We show how the basic ideas of geometric quantization are
`categorified' in this context: just as representations of groups correspond to
equivariant line bundles, 2-representations of groups correspond to equivariant
gerbes. We also show how the 2-character of a 2-representation can be made
functorial with respect to morphisms of 2-representations. Under the geometric
correspondence, the 2-character of a 2-representation corresponds to the
geometric character of its associated equivariant gerbe. This enables us to
show that the complexified 2-character is a unitarily fully faithful functor
from the complexified homotopy category of unitary 2-representations to the
category of unitary equivariant vector bundles over the group.


title:
Comment on "Bayesian Analysis of Pentaquark Signals from CLAS Data",
  with Response to the Reply by Ireland and Protopopsecu

abstract:
  The CLAS Collaboration has published an analysis using Bayesian model
selection. My Comment criticizing their use of arbitrary prior probability
density functions, and a Reply by D.G. Ireland and D. Protopopsecu, have now
been published as well. This paper responds to the Reply and discusses the
issues in more detail, with particular emphasis on the problems of priors in
Bayesian model selection.


title:
Scaling Relations and the Fundamental Line of the Local Group Dwarf
  Galaxies

abstract:
  We study the scaling relations between global properties of dwarf galaxies in
the Local Group. In addition to quantifying the correlations between pairs of
variables, we explore the "shape" of the distribution of galaxies in log
parameter space using standardised Principal Component Analysis (PCA), the
analysis is performed first in the 3-D structural parameter space of stellar
mass M*, internal velocity V and characteristic radius R* (or surface
brightness mu*). It is then extended to a 4-D space that includes a
stellar-population parameter such as metallicity Z or star formation rate SFR.
We find that the Local-Group dwarfs basically define a one-parameter
"Fundamental Line" (FL), primarily driven by stellar mass, M*. A more detailed
inspection reveals differences between the star-formation properties of dwarf
irregulars (dI's) and dwarf ellipticals (dE's), beyond the tendency of the
latter to be more massive. In particular, the metallicities of dI's are
typically lower by a factor of 3 at a given M* and they grow faster with
increasing M*, showing a tighter FL in the 4-D space for the dE's. The
structural scaling relations of dI's resemble those of the more massive
spirals, but the dI's have lower star formation rates for a given M* which also
grow faster with increasing M*. On the other hand, the FL of the dE's departs
from the fundamental plane of bigger ellipticals. While the one-parameter
nature of the FL and the associated slopes of the scaling relations are
consistent with the general predictions of supernova feedback (Dekel & Woo
2003), the differences between the FL's of the dE's and the dI's remain a
challenge and should serve as a guide for the secondary physical processes
responsible for these two types.


title:
Atomistic Simulation of Compression Wave Propagation in Nanoporous
  Materials

abstract:
  We have developed a method to simulate behavior of nanoporous materials in a
molecular dynamics code. The nanoporous solid is produced via a spinodal
decomposition of a material brought from a supercritical fluid into the two
phase (liquid-vapor) region and then quenching and freezing the liquid into an
interconnected nanoporous solid. We have simulated, at the atomic level,
compression in crystal/nanoporous configurations, demonstrating that this is a
powerful technique for studying the equation-of-state of cold and warm dense
matter. By performing compression simulations relevant to high energy density
physics experiments, we have been able to elucidate experimental measurement by
identifying governing microscopic mechanisms.


title: Robust Cryptography in the Noisy-Quantum-Storage Model

abstract:
  It was shown in [WST08] that cryptographic primitives can be implemented
based on the assumption that quantum storage of qubits is noisy. In this work
we analyze a protocol for the universal task of oblivious transfer that can be
implemented using quantum-key-distribution (QKD) hardware in the practical
setting where honest participants are unable to perform noise-free operations.
We derive trade-offs between the amount of storage noise, the amount of noise
in the operations performed by the honest participants and the security of
oblivious transfer which are greatly improved compared to the results in
[WST08]. As an example, we show that for the case of depolarizing noise in
storage we can obtain secure oblivious transfer as long as the quantum
bit-error rate of the channel does not exceed 11% and the noise on the channel
is strictly less than the quantum storage noise. This is optimal for the
protocol considered. Finally, we show that our analysis easily carries over to
quantum protocols for secure identification.


title:
Decomposition of the Host Galaxies of Active Galactic Nuclei Using
  Hubble Space Telescope Images

abstract:
  Investigating the link between supermassive black hole and galaxy evolution
requires careful measurements of the properties of the host galaxies. We
perform simulations to test the reliability of a two-dimensional image-fitting
technique to decompose the host galaxy and the active galactic nucleus (AGN),
especially on images obtained using cameras onboard the Hubble Space Telescope
(HST), such as the Wide-Field Planetary Camera 2, the Advanced Camera for
Surveys, and the Near-Infrared Camera and Multi-Object Spectrometer. We
quantify the relative importance of spatial, temporal, and color variations of
the point-spread function (PSF). To estimate uncertainties in AGN-to-host
decompositions, we perform extensive simulations that span a wide range in
AGN-to-host galaxy luminosity contrast, signal-to-noise ratio, and host galaxy
properties (size, luminosity, central concentration). We find that realistic
PSF mismatches that typically afflict actual observations systematically lead
to an overestimate of the flux of the host galaxy. Part of the problem is
caused by the fact that the HST PSFs are undersampled. We demonstrate that this
problem can be mitigated by broadening both the science and the PSF images to
critical sampling without loss of information. Other practical suggestions are
given for optimal analysis of HST images of AGN host galaxies.


title: Gravity Waves Signatures from Anisotropic pre-Inflation

abstract:
  We show that expanding or contracting Kasner universes are unstable due to
the amplification of gravitational waves (GW). As an application of this
general relativity effect, we consider a pre-inflationary anisotropic geometry
characterized by a Kasner-like expansion, which is driven dynamically towards
inflation by a scalar field. We investigate the evolution of linear metric
fluctuations around this background, and calculate the amplification of the
long-wavelength GW of a certain polarization during the anisotropic expansion
(this effect is absent for another GW polarization, and for scalar
fluctuations). These GW are superimposed to the usual tensor modes of quantum
origin from inflation, and are potentially observable if the total number of
inflationary e-folds exceeds the minimum required to homogenize the observable
universe only by a small margin. Their contribution to the temperature
anisotropy angular power spectrum decreases with the multipole l as l^(-p),
where p depends on the slope of the initial GW power-spectrum. Constraints on
the long-wavelength GW can be translated into limits on the total duration of
inflation and the initial GW amplitude. The instability of classical GW (and
zero-vacuum fluctuations of gravitons) during Kasner-like expansion (or
contraction) may have other interesting applications. In particular, if GW
become non-linear, they can significantly alter the geometry before the onset
of inflation.


title:
Minimization variational principles for acoustics, elastodynamics, and
  electromagnetism in lossy inhomogeneous bodies at fixed frequency

abstract:
  The classical energy minimization principles of Dirichlet and Thompson are
extended as minimization principles to acoustics, elastodynamics and
electromagnetism in lossy inhomogeneous bodies at fixed frequency. This is done
by building upon ideas of Cherkaev and Gibiansky, who derived minimization
variational principles for quasistatics. In the absence of free current the
primary electromagnetic minimization variational principles have a minimum
which is the time-averaged electrical power dissipated in the body. The
variational principles provide constraints on the boundary values of the fields
when the moduli are known. Conversely, when the boundary values of the fields
have been measured, then they provide information about the values of the
moduli within the body. This should have application to electromagnetic
tomography. We also derive saddle point variational principles which correspond
to variational principles of Gurtin, Willis, and Borcea.

categories: math-ph cond-mat.mtrl-sci math.AP math.MP physics.class-ph physics.optics


title:
The Origin of the Intrinsic Scatter in the Relation Between Black Hole
  Mass and Bulge Luminosity for Nearby Active Galaxies

abstract:
  We investigate the origin of the intrinsic scatter in the correlation between
black hole mass (MBH) and bulge luminosity [L(bulge)] in a sample of 45
massive, local (z < 0.35) type~1 active galactic nuclei (AGNs). We derive MBH
from published optical spectra assuming a spherical broad-line region, and
L(bulge) from detailed two-dimensional decomposition of archival optical Hubble
Space Telescope images. AGNs follow the MBH-L(bulge) relation of inactive
galaxies, but the zero point is shifted by an average of \Delta log MBH ~ -0.3
dex. We show that the magnitude of the zero point offset, which is responsible
for the intrinsic scatter in the MBH-L(bulge) relation, is correlated with
several AGN and host galaxy properties, all of which are ultimately related to,
or directly impact, the BH mass accretion rate. At a given bulge luminosity,
sources with higher Eddington ratios have lower MBH. The zero point offset can
be explained by a change in the normalization of the virial product used to
estimate MBH, in conjunction with modest BH growth (~ 10%--40%) during the AGN
phase. Galaxy mergers and tidal interactions appear to play an important role
in regulating AGN fueling in low-redshift AGNs.


title: The operational meaning of min- and max-entropy

abstract:
  We show that the conditional min-entropy Hmin(A|B) of a bipartite state
rho_AB is directly related to the maximum achievable overlap with a maximally
entangled state if only local actions on the B-part of rho_AB are allowed. In
the special case where A is classical, this overlap corresponds to the
probability of guessing A given B. In a similar vein, we connect the
conditional max-entropy Hmax(A|B) to the maximum fidelity of rho_AB with a
product state that is completely mixed on A. In the case where A is classical,
this corresponds to the security of A when used as a secret key in the presence
of an adversary holding B. Because min- and max-entropies are known to
characterize information-processing tasks such as randomness extraction and
state merging, our results establish a direct connection between these tasks
and basic operational problems. For example, they imply that the (logarithm of
the) probability of guessing A given B is a lower bound on the number of
uniform secret bits that can be extracted from A relative to an adversary
holding B.


title: Compressibility of solid helium

abstract:
  The compressibility of solid helium (3He and 4He) in the hcp and fcc phases
has been studied by path-integral Monte Carlo. Simulations were carried out in
both canonical (NVT) and isothermal-isobaric (NPT) ensembles at temperatures
between 10 and 300 K, showing consistent results in both ensembles. For
pressures between 4 and 10 GPa, the bulk modulus B is found to decrease by
about 10 %, when temperature increases from the low-temperature limit to the
melting temperature. The isotopic effect on the bulk modulus of helium crystals
has been quantified in a wide range of parameters. At 25 K and pressures on the
order of 1 GPa, the relative difference between 3He and 4He amounts to about 2
%. The thermal expansion has been also quantified from results obtained in both
NPT and NVT simulations.


title:
Unusual field dependence of remanent magnetization in granular CrO2:
  possible role of piezomagnetism

abstract:
  We present low field thermoremanent magnetization (TRM) measurements in
granular CrO2 and composites of ferromagnetic (FM) CrO2 and antiferromagnetic
(AFM) Cr2O3. TRM in these samples is seen to display two distinct time scales.
A quasi static part of remanence, appearing only in low field regime exhibits a
peculiar field dependence. TRM is seen to first rise and then fall with
increasing cooling fields, eventually vanishing above a critical field. Similar
features in TRM have previously been observed in some antiferromagnets that
exhibit the phenomenon of piezomagnetism. Scaling analysis of the TRM data
suggest that presumably piezomoments generated in the AFM component drive the
FM magnetization dynamics in these granular systems in low field regime.


title: Surgery obstructions from Khovanov homology

abstract:
  For a 3-manifold with torus boundary admitting an appropriate involution, we
show that Khovanov homology provides obstructions to certain exceptional Dehn
fillings. For example, given a strongly invertible knot in S^3, we give
obstructions to lens space surgeries, as well as obstructions to surgeries with
finite fundamental group. These obstructions are based on homological width in
Khovanov homology, and in the case of finite fundamental group depend on a
calculation of the homological width for a family of Montesinos links.


title: Tight frames of exponentially decaying Wannier functions

abstract:
  Let L be a Schroedinger operator with periodic magnetic and electric
potentials, a Maxwell operator in a periodic medium, or an arbitrary
self-adjoint elliptic linear partial differential operator in R^n with
coefficients periodic with respect to a lattice G. Let also S be a finite part
of its spectrum separated by gaps from the rest of the spectrum. We consider
the old question of existence of a finite set of exponentially decaying Wannier
functions such that their G-shifts span the whole spectral subspace
corresponding to S in some "nice" manner. It is known that a topological
obstruction might exist to finding exponentially decaying Wannier functions
that form an orthonormal basis of the spectral subspace. This obstruction has
the form of non-triviality of certain finite dimensional (with the dimension
equal to the number of spectral bands in S) analytic vector bundle. We show
that it is always possible to find a finite number of exponentially decaying
composite Wannier functions such that their G-shifts form a 1-tight frame in
the spectral subspace. This appears to be the best, one can do when the
topological obstruction is present. The number of the functions is the smallest
dimension of a trivial bundle containing an equivalent copy of the "obstacle
bundle". In particular, it coincides with the number of spectral bands if and
only if the bundle is trivial, in which case an orthonormal basis of
exponentially decaying composite Wannier functions is known to exist. An
estimate on this number is provided.


title:
Unconventional Landau levels in bulk graphite revealed by Raman
  spectroscopy

abstract:
  The electronic Raman scattering of bulk graphite at zero magnetic field
reveals a structureless signal characteristic of a metal. For T<~100 K and B >
2 T, several peaks at energies scaling linearly with magnetic field were
observed and ascribed to transitions from the lowest energy Landau level(s)
(LL) to excited states belonging to the same ladder. The LLs are equally
(unequally) spaced for high (low) quantum numbers, being surprisingly
consistent with the LL sequence from massive Dirac Fermions (m* = 0.033(2) m_e)
with Berry's phase 2\pi found in graphene bilayers. These results provide
spectroscopic evidence that much of the unconventional physics recently
revealed by graphene multilayers is also shared by bulk graphite.


title: Surface waves in photonic crystal slabs

abstract:
  Photonic crystals with a finite size can support surface modes when
appropriately terminated. We calculate the dispersion curves of surface modes
for different terminations using the plane wave expansion method. These
non-radiative surface modes can be excited with the help of attenuated total
reflection technique. We did experiments and simulations to trace the surface
band curve, both in good agreement with the numerical calculations.


title:
Hartree-Fock ground state of the two-dimensional electron gas with
  Rashba spin-orbit interaction

abstract:
  We search for the uniform Hartree-Fock ground state of the two-dimensional
electron gas formed in semiconductor heterostructures including the Rashba
spin-orbit interaction. We identify two competing quantum phases: a
ferromagnetic one with partial spin polarization in the perpendicular direction
and a paramagnetic one with in-plane spin. We present a phase diagram in terms
of the relative strengths of the Rashba to the Coulomb interaction and the
electron density. We compare our theoretical description with existing
experimental results obtained in GaAs-AlGaAs heterostructures.


title: Field Flows of Dark Energy

abstract:
  Scalar field dark energy evolving from a long radiation- or matter-dominated
epoch has characteristic dynamics. While slow-roll approximations are invalid,
a well defined field expansion captures the key aspects of the dark energy
evolution during much of the matter-dominated epoch. Since this behavior is
determined, it is not faithfully represented if priors for dynamical quantities
are chosen at random. We demonstrate these features for both thawing and
freezing fields, and for some modified gravity models, and unify several
special cases in the literature.


title: A multimodular algorithm for computing Bernoulli numbers

abstract:
  We describe an algorithm for computing Bernoulli numbers. Using a parallel
implementation, we have computed B(k) for k = 10^8, a new record. Our method is
to compute B(k) modulo p for many small primes p, and then reconstruct B(k) via
the Chinese Remainder Theorem. The asymptotic time complexity is O(k^2
log(k)^(2+epsilon)), matching that of existing algorithms that exploit the
relationship between B(k) and the Riemann zeta function. Our implementation is
significantly faster than several existing implementations of the zeta-function
method.


title: The short GRB070707 afterglow and its very faint host galaxy

abstract:
  We present the results from an ESO/VLT campaign aimed at studying the
afterglow properties of the short/hard gamma ray burst GRB 070707. Observations
were carried out at ten different epochs from ~0.5 to ~80 days after the event.
The optical flux decayed steeply with a power-law decay index greater than 3,
later levelling off at R~27.3 mag; this is likely the emission level of the
host galaxy, the faintest yet detected for a short GRB. Spectroscopic
observations did not reveal any line features/edges that could unambiguously
pinpoint the GRB redshift, but set a limit z < 3.6. In the range of allowed
redshifts, the host has a low luminosity, comparable to that of long-duration
GRBs. The existence of such faint host galaxies suggests caution when
associating short GRBs with bright, offset galaxies, where the true host might
just be too dim for detection. The steepness of the decay of the optical
afterglow of GRB 070707 challenges external shock models for the optical
afterglow of short/hard GRBs. We argue that this behaviour might results from
prolonged activity of the central engine or require alternative scenarios.


title:
Bagger-Lambert theory on an orbifold and its relation to
  Chern-Simons-matter theories

abstract:
  We consider how to take an orbifold reduction for the multiple M2-brane
theory recently proposed by Bagger and Lambert, and discuss its relation to
Chern-Simons theories. Starting from the infinite dimensional 3-algebra
realized as the Nambu bracket on a 3-torus, we first suggest an orbifolding
prescription for various fields. Then we introduce a second truncation, which
effectively reduces the internal space to a 2-torus. Eventually one obtains a
large-N limit of Chern-Simons gauge theories coupled to matter fields. We
consider an abelian orbifold C^4/Z_n, and illustrate how one can arrive at the
N=6 supersymmetric theories with gauge groups U(N) x U(N) and Chern-Simons
levels (k,-k), as recently constructed by Aharony, Bergman, Jafferis and
Maldacena.


title: Reinforced walks in two and three dimensions

abstract:
  In probability theory, reinforced walks are random walks on a lattice (or
more generally a graph) that preferentially revisit neighboring `locations'
(sites or bonds) that have been visited before. In this paper, we consider
walks with one-step reinforcement, where one preferentially \emph{revisits}
locations irrespective of the number of visits. Previous numerical simulations
[A. Ordemann {\it et al.}, Phys. Rev. E {\bf 64}, 046117 (2001)] suggested that
the site model on the lattice shows a phase transition at finite reinforcement
between a random-walk like and a collapsed phase, in both 2 and 3 dimensions.
The very different mathematical structure of bond and site models might also
suggest different phenomenology (critical properties, etc.). We use high
statistics simulations and heuristic arguments to suggest that site and bond
reinforcement are in the same universality class, and that the purported phase
transition in 2 dimensions actually occurs at zero coupling constant. We also
show that a quasi-static approximation predicts the large time scaling of the
end-to-end distance in the collapsed phase of both site and bond reinforcement
models, in excellent agreement with simulation results.


title:
Nonsymmetric interpolation Macdonald polynomials and g_n basic
  hypergeometric series

abstract:
  The Knop-Sahi interpolation Macdonald polynomials are inhomogeneous and
nonsymmetric generalisations of the well-known Macdonald polynomials. In this
paper we apply the interpolation Macdonald polynomials to study a new type of
basic hypergeometric series of type g_n. Our main results include a new
q-binomial theorem, new q-Gauss sum, and several transformation formulae for
g_n series.


title: Dissipationless BCS Dynamics with Large Branch Imbalance

abstract:
  In many situations a BCS-type superconductor will develop an imbalance
between the populations of the holelike and electronlike spectral branches.
This imbalance suppresses the gap. It has been noted by Gal'perin et al. [Sov.
Phys. JETP 54, 1126 (1981)] that at large imbalance, when the gap is
substantially suppressed, an instability develops. The analytic treatment of
the system beyond the instability point is complicated by the fact that the
Boltzmann approach breaks down. We study the short-time behavior following the
instability, in the collisionless regime, using methods developed by Yuzbashyan
et al. [J. Phys. A 38, 7831 (2005); Phys. Rev. B 72, 220503(R) (2005)].


title:
Second structure relation for $q$-semiclassical polynomials of the Hahn
  Tableau

abstract:
  The q-classical orthogonal polynomials of the q-Hahn Tableau are
characterized from their orthogonality condition and by a first and a second
structure relation. Unfortunately, for the q-semiclassical orthogonal
polynomials (a generalization of the classical ones) we find only in the
literature the first structure relation. In this paper, a second structure
relation is deduced. In particular, by means of a general finite-type relation
between a q-semiclassical polynomial sequence and the sequence of its
q-differences such a structure relation is obtained.


title:
Evidence for a Turnover in the IMF of Low Mass Stars and Sub-stellar
  Objects: Analysis from an Ensemble of Young Clusters

abstract:
  We present a combined analysis of the low-mass Initial Mass Function (IMF)
for seven star forming regions. We first demonstrate that the ratios of stars
to brown dwarfs are consistent with a single underlying IMF. Assuming the
underlying IMF is the same for all seven clusters and by combining the ratio of
stars to brown dwarfs from each cluster we constrain the shape of the brown
dwarf IMF and find it to be consistent with a log--normal IMF. This provides
the strongest constraint yet that the sub-stellar IMF turns over (dN/dM
M^(-alpha), alpha < 0).


title:
Thermoacoustic tomography with detectors on an open curve: an efficient
  reconstruction algorithm

abstract:
  Practical applications of thermoacoustic tomography require numerical
inversion of the spherical mean Radon transform with the centers of integration
spheres occupying an open surface. Solution of this problem is needed (both in
2-D and 3-D) because frequently the region of interest cannot be completely
surrounded by the detectors, as it happens, for example, in breast imaging. We
present an efficient numerical algorithm for solving this problem in 2-D
(similar methods are applicable in the 3-D case). Our method is based on the
numerical approximation of plane waves by certain single layer potentials
related to the acquisition geometry. After the densities of these potentials
have been precomputed, each subsequent image reconstruction has the complexity
of the regular filtration backprojection algorithm for the classical Radon
transform. The peformance of the method is demonstrated in several numerical
examples: one can see that the algorithm produces very accurate reconstructions
if the data are accurate and sufficiently well sampled, on the other hand, it
is sufficiently stable with respect to noise in the data.


title: Evaporative Cooling of a Photon Fluid to Quantum Degeneracy

abstract:
  We demonstrate that the process of evaporative cooling, as associated with
the cooling of atomic gases, can also be employed to condense a system of
photons giving rise to coherent properties of the light. The system we study
consists of photons in a high-quality Fabry-Perot cavity with photon
interactions mediated by a nonlinear atomic medium. We predict a macroscopic
occupation of the lowest energy mode and evaluate the conditions for realizing
a narrow spectral width indicative of a long coherence time for the field.


title: Time-Dependent Quantum Weak Values: Decay Law for Post-Selected States

abstract:
  Weak measurements offer new insights into the behavior of quantum systems.
Combined with post-selection, quantum mechanics predicts a range of new
experimentally testable phenomena. In this paper I consider weak measurements
performed on time-dependent pre- and post-selected ensembles, with emphasis on
the decay of excited states. The results show that the standard exponential
decay law is a limiting case of a more general law that depends on both the
time of post-selection and the choice of final state. The generalized law is
illustrated for two interesting choices of post-selection.


title: Dirac particles' tunnelling from black rings

abstract:
  Recent research shows that Hawking radiation can be treated as a quantum
tunnelling process, and Hawking temperature of Dirac particles across the
horizon of a black hole can be correctly recovered via fermions tunnelling
method. In this paper, motivated by fermions tunnelling method, we attempt to
apply the analysis to derive Hawking radiation of Dirac particles via
tunnelling from black ring solutions of 5-dimensional Einstein-Maxwell-dilaton
gravity theory. Finally, it is interesting to find as in black hole cases,
fermions tunnelling can also result in correct Hawking temperatures for the
rotating neutral, dipole and charged black rings.


title:
Adaptive multiresolution schemes with local time stepping for
  two-dimensional degenerate reaction-diffusion systems

abstract:
  We present a fully adaptive multiresolution scheme for spatially
two-dimensional, possibly degenerate reaction-diffusion systems, focusing on
combustion models and models of pattern formation and chemotaxis in
mathematical biology. Solutions of these equations in these applications
exhibit steep gradients, and in the degenerate case, sharp fronts and
discontinuities. The multiresolution scheme is based on finite volume
discretizations with explicit time stepping. The multiresolution representation
of the solution is stored in a graded tree. By a thresholding procedure, namely
the elimination of leaves that are smaller than a threshold value, substantial
data compression and CPU time reduction is attained. The threshold value is
chosen optimally, in the sense that the total error of the adaptive scheme is
of the same slope as that of the reference finite volume scheme. Since chemical
reactions involve a large range of temporal scales, but are spatially well
localized (especially in the combustion model), a locally varying adaptive time
stepping strategy is applied. It turns out that local time stepping accelerates
the adaptive multiresolution method by a factor of two, while the error remains
controlled.


title: Electronic Structures of SiC Nanoribbons

abstract:
  Electronic structures of SiC nanoribbons have been studied by spin-polarized
density functional calculations. The armchair nanoribbons are nonmagnetic
semiconductor, while the zigzag nanoribbons are magnetic metal. The spin
polarization in zigzag SiC nanoribbons is originated from the unpaired
electrons localized on the ribbon edges. Interestingly, the zigzag nanoribbons
narrower than $\sim$4 nm present half-metallic behavior. Without the aid of
external field or chemical modification, the metal-free half-metallicity
predicted for narrow SiC zigzag nanoribbons opens a facile way for nanomaterial
spintronics applications.


title:
Evaluation of specific heat for superfluid helium between 0 - 2.1 K
  based on nonlinear theory

abstract:
  The specific heat of liquid helium was calculated theoretically in the Landau
theory. The results deviate from experimental data in the temperature region of
1.3 - 2.1 K. Many theorists subsequently improved the results of the Landau
theory by applying temperature dependence of the elementary excitation energy.
As well known, many-body system has a total energy of Galilean covariant form.
Therefore, the total energy of liquid helium has a nonlinear form for the
number distribution function. The function form can be determined using the
excitation energy at zero temperature and the latent heat per helium atom at
zero temperature. The nonlinear form produces new temperature dependence for
the excitation energy from Bose condensate. We evaluate the specific heat using
iteration method. The calculation results of the second iteration show good
agreement with the experimental data in the temperature region of 0 - 2.1 K,
where we have only used the elementary excitation energy at 1.1 K.


title:
Complete State Reconstruction of a Two-Mode Gaussian State via Local
  Operations and Classical Communication

abstract:
  We propose a strictly local quantum tomography protocol for a bipartite
system. We show that the joint density matrix of an arbitrary two-mode Gaussian
state, entangled or not, is obtained via local operations and classical
communication only. In contrast to previous proposals, simultaneous homodyne
measurements (HM) on both modes are replaced by local homodyne detections and a
set of local projective measurements.


title:
Beyond the Quantum Adiabatic Approximation: Adiabatic Perturbation
  Theory

abstract:
  We introduce a perturbative approach to solving the time dependent
Schroedinger equation, named adiabatic perturbation theory (APT), whose zeroth
order term is the quantum adiabatic approximation. The small parameter in the
power series expansion of the time-dependent wave function is the inverse of
the time it takes to drive the system's Hamiltonian from the initial to its
final form. We review other standard perturbative and non-perturbative ways of
going beyond the adiabatic approximation, extending and finding exact relations
among them, and also compare the efficiency of those methods against the APT.
Most importantly, we determine APT corrections to the Berry phase by use of the
Aharonov-Anandan geometric phase. We then solve several time dependent problems
allowing us to illustrate that the APT is the only perturbative method that
gives the right corrections to the adiabatic approximation. Finally, we propose
an experiment to measure the APT corrections to the Berry phase and show, for a
particular spin-1/2 problem, that to first order in APT the geometric phase
should be two and a half times the (adiabatic) Berry phase.


title: Locality and nonlocality in quantum pure-state identification problems

abstract:
  Suppose we want to identify an input state with one of two unknown reference
states, where the input state is guaranteed to be equal to one of the reference
states. We assume that no classical knowledge of the reference states is given,
but a certain number of copies of them are available instead. Two reference
states are independently and randomly chosen from the state space in a unitary
invariant way. This is called the quantum state identification problem, and the
task is to optimize the mean identification success probability. In this paper,
we consider the case where each reference state is pure and bipartite, and
generally entangled. The question is whether the maximum mean identification
success probability can be attained by means of a local operations and
classical communication (LOCC) measurement scheme. Two types of identification
problems are considered when a single copy of each reference state is
available. We show that a LOCC scheme attains the globally achievable
identification probability in the minimum-error identification problem. In the
unambiguous identification problem, however, the maximal success probability by
means of LOCC is shown to be less than the globally achievable identification
probability.


title: Neutron Electric Dipole Moment at Fixed Topology

abstract:
  We describe the finite volume effects of CP-odd quantities, such as the
neutron electric dipole moment and the anapole moment in the $\theta$-vacuum,
under different topological sectors. We evaluate the three-point Green's
functions for the electromagnetic current in a fixed non-trivial topological
sector in order to extract these CP-odd observables. We discuss the role of
zero modes in the CP-odd Green's function and show that, in the quenched
approximation, there is a power divergence in the quark mass for CP-odd
quantities at finite volume.


title: Properties of hyperkahler manifolds and their twistor spaces

abstract:
  We describe the relation between supersymmetric sigma-models on hyperkahler
manifolds, projective superspace, and twistor space. We review the essential
aspects and present a coherent picture with a number of new results.


title: Shaping Robust System through Evolution

abstract:
  Biological functions are generated as a result of developmental dynamics that
form phenotypes governed by genotypes. The dynamical system for development is
shaped through genetic evolution following natural selection based on the
fitness of the phenotype. Here we study how this dynamical system is robust to
noise during development and to genetic change by mutation. We adopt a
simplified transcription regulation network model to govern gene expression,
which gives a fitness function. Through simulations of the network that
undergoes mutation and selection, we show that a certain level of noise in gene
expression is required for the network to acquire both types of robustness. The
results reveal how the noise that cells encounter during development shapes any
network's robustness, not only to noise but also to mutations. We also
establish a relationship between developmental and mutational robustness
through phenotypic variances caused by genetic variation and epigenetic noise.
A universal relationship between the two variances is derived, akin to the
fluctuation-dissipation relationship known in physics.

categories: q-bio.PE cond-mat.stat-mech nlin.AO physics.bio-ph


title:
Quantum and classical vibrational relaxation dynamics of
  N-methylacetamide on ab initio potential energy surfaces

abstract:
  Employing extensive quantum-chemical calculations at the DFT/B3LYP and MP2
level, a quartic force field of isolated N-methylacetamide is constructed.
Taking into account 24 vibrational degrees of freedom, the model is employed to
perform numerically exact vibrational configuration interaction calculations of
the vibrational energy relaxation of the amide I mode. It is found that the
energy transfer pathways may sensitively depend on details of the theoretical
description. Moreover, the exact reference calculations were used to study the
applicability and accuracy of (i) the quasiclassical trajectory method, (ii)
time-dependent second-order perturbation theory, and (iii) the instantaneous
normal mode description of frequency fluctuations. Based on the results,
several strategies to describe vibrational energy relaxation in biomolecular
systems are discussed.


title:
Dynamic treatment of vibrational energy relaxation in a heterogeneous
  and fluctuating environment

abstract:
  A computational approach to describe the energy relaxation of a
high-frequency vibrational mode in a fluctuating heterogeneous environment is
outlined. Extending previous work [H. Fujisaki, Y. Zhang, and J.E. Straub, J.
Chem. Phys. {\bf 124}, 144910 (2006)], second-order time-dependent perturbation
theory is employed which includes the fluctuations of the parameters in the
Hamiltonian within the vibrational adiabatic approximation. This means that the
time-dependent vibrational frequencies along an MD trajectory are obtained via
a partial geometry optimization of the solute with fixed solvent and a
subsequent normal mode calculation. Adopting the amide I mode of
N-methylacetamide in heavy water as a test problem, it is shown that the
inclusion of dynamic fluctuations may significantly change the vibrational
energy relaxation. In particular, it is found that relaxation occurs in two
phases, because for short times ($\lesssim$ 200 fs) the spectral density
appears continuous due to the frequency-time uncertainty relation, while at
longer times the discrete nature of the bath becomes apparent. Considering the
excellent agreement between theory and experiment, it is speculated if this
behavior can explain the experimentally obtained biphasic relaxation the amide
I mode of N-methylacetamide.


title: Operator fidelity susceptibility, decoherence and quantum criticality

abstract:
  The extension of the notion of quantum fidelity from the state-space level to
the operator one can be used to study environment-induced decoherence.
state-dependent operator fidelity sucepti- bility (OFS), the leading order term
for slightly different operator parameters, is shown to have a nontrivial
behavior when the environment is at critical points. Two different
contributions to OFS are identified which have distinct physical origins and
temporal dependence. Exact results for the finite-temperature decoherence
caused by a bath described by the Ising model in transverse field are obtained.


title: Quasinormal modes for topologically massive black hole

abstract:
  We calculate quasinormal modes of a massive scalar perturbation on the
topologically massive black hole (CS-BTZ black hole). The chiral point of $\mu
\ell=1$ corresponds to a newly extremal black hole. We show that there is no
quasinormal modes at this point. Accordingly, we prove the unitarity of the
CS-BTZ black hole at the chiral point.


title: Communication over Finite-Field Matrix Channels

abstract:
  This paper is motivated by the problem of error control in network coding
when errors are introduced in a random fashion (rather than chosen by an
adversary). An additive-multiplicative matrix channel is considered as a model
for random network coding. The model assumes that n packets of length m are
transmitted over the network, and up to t erroneous packets are randomly chosen
and injected into the network. Upper and lower bounds on capacity are obtained
for any channel parameters, and asymptotic expressions are provided in the
limit of large field or matrix size. A simple coding scheme is presented that
achieves capacity in both limiting cases. The scheme has decoding complexity
O(n^2 m) and a probability of error that decreases exponentially both in the
packet length and in the field size in bits. Extensions of these results for
coherent network coding are also presented.


title: Dust-driven Dynamos in Accretion Disks

abstract:
  Magnetically driven astrophysical jets are related to accretion and involve
toroidal magnetic field pressure inflating poloidal magnetic field flux
surfaces. Examination of particle motion in combined gravitational and magnetic
fields shows that these astrophysical jet toroidal and poloidal magnetic fields
can be powered by the gravitational energy liberated by accreting dust grains
that have become positively charged by emitting photo-electrons. Because a dust
grain experiences magnetic forces after becoming charged, but not before,
charging can cause irreversible trapping of the grain so dust accretion is a
consequence of charging. Furthermore, charging causes canonical angular
momentum to replace mechanical angular momentum as the relevant constant of the
motion. The resulting effective potential has three distinct classes of
accreting particles distinguished by canonical angular momentum, namely (i)
"cyclotron-orbit", (ii) "Speiser-orbit", and (iii) "zero canonical angular
momentum" particles. Electrons and ions are of class (i) but depending on mass
and initial orbit inclination, dust grains can be of any class. Light-weight
dust grains develop class (i) orbits such that the grains are confined to
nested poloidal flux surfaces, whereas grains with a critical weight such that
they experience comparable gravitational and magnetic forces can develop class
(ii) or class (iii) orbits, respectively producing poloidal and toroidal field
dynamos.


title:
Investigating thermal evolution of the self-gravitating one dimensional
  molecular cloud by smoothed particle hydrodynamics

abstract:
  The heating of the ion-neutral (or ambipolar) diffusion may affect the
thermal phases of the molecular clouds. We present an investigation on the
effect of this heating mechanism in the thermal instability of the molecular
clouds. A weakly ionized one dimensional slab geometry, which is allowed for
self-gravity and ambipolar diffusion, is chosen to study its thermal phases. We
use the thermodynamic evolution of the slab to obtain the regions where slab
cloud becomes thermally unstable. We investigate this evolution using the model
of ambipolar diffusion with two-fluid smoothed particle hydrodynamics, as
outlined by Hosking & Whitworth. Firstly, some parts of the technique are
improved to test the pioneer works on behavior of the ambipolar diffusion in an
isothermal self-gravitating slab. Afterwards, the improved two-fluid technique
is used for thermal evolution of the slab. The results show that the thermal
instability may persist inhomogeneities with a large density contrast at the
intermediate parts of the cloud. We suggest that this feature may be
responsible for the planet formation in the intermediate regions of a
collapsing molecular cloud and/or may also be relevant to the formation of star
forming dense cores in the clumps.


title:
Molecular Dynamics of a kB DNA Element: Base Flipping via Cross-strand
  Intercalative Stacking in a Microsecond-scale Simulation

abstract:
  The sequence-dependent structural variability and conformational dynamics of
DNA play pivotal roles in many biological milieus, such as in the site-specific
binding of transcription factors to target regulatory elements. To better
understand DNA structure, function, and dynamics in general, and protein-DNA
recognition in the 'kB' family of genetic regulatory elements in particular, we
performed molecular dynamics simulations of a 20-base pair DNA encompassing a
cognate kB site recognized by the proto-oncogenic 'c-Rel' subfamily of NF-kB
transcription factors. Simulations of the kB DNA in explicit water were
extended to microsecond duration, providing a broad, atomically-detailed
glimpse into the structural and dynamical behavior of double helical DNA over
many timescales. Of particular note, novel (and structurally plausible)
conformations of DNA developed only at the long times sampled in this
simulation -- including a peculiar state arising at ~ 0.7 us and characterized
by cross-strand intercalative stacking of nucleotides within a
longitudinally-sheared base pair, followed (at ~ 1 us) by spontaneous base
flipping of a neighboring thymine within the A-rich duplex. Results and
predictions from the us-scale simulation include implications for a dynamical
NF-kB recognition motif, and are amenable to testing and further exploration
via specific experimental approaches that are suggested herein.


title:
Some sufficient conditions of a given series with rational terms
  converging to an irrational number or a transcdental number

abstract:
  In this paper, we propose various sufficient conditions to determine if a
given real number is an irrational number or a transcendental number and also
apply these conditions to some interesting examples, particularly,one of them
comes from complex analytic dynamics


title:
Direct observation of optically induced transient structures in graphite
  using ultrafast electron crystallography

abstract:
  We use ultrafast electron crystallography to study structural changes induced
in graphite by a femtosecond laser pulse. At moderate fluences of ~< 21mJ/cm^2,
lattice vibrations are observed to thermalize on a time scale of ~8ps. At
higher fluences approaching the damage threshold, lattice vibration amplitudes
saturate. Following a marked initial contraction, graphite is driven
nonthermally into a transient state with sp^3-like character, forming
interlayer bonds. Using ab initio density functional calculations, we trace the
governing mechanism back to electronic structure changes following the
photo-excitation.


title:
Stability of temporal solitons in uniform and "managed" quadratic
  nonlinear media with opposite group-velocity dispersions at fundamental and
  second harmonics

abstract:
  The problem of the stability of solitons in second-harmonic-generating media
with normal group-velocity dispersion (GVD) in the second-harmonic (SH) field,
which is generic to available chi^(2) materials, is revisited. Using an
iterative numerical scheme to construct stationary soliton solutions, and
direct simulations to test their stability, we identify a full
soliton-stability range in the space of the system's parameters, including the
coefficient of the group-velocity-mismatch (GVM). The soliton stability is
limited by an abrupt onset of growth of tails in the SH component, the relevant
stability region being defined as that in which the energy loss to the tail
generation is negligible under experimentally relevant conditions. We
demonstrate that the stability domain can be readily expanded with the help of
two "management" techniques (spatially periodic compensation of destabilizing
effects) - the dispersion management (DM) and GVM management. In comparison
with their counterparts in optical fibers, DM solitons in the chi^(2) medium
feature very weak intrinsic oscillations.


title:
A constrained stochastic state selection method applied to quantum spin
  systems

abstract:
  We describe a further development of the stochastic state selection method,
which is a kind of Monte Carlo method we have proposed in order to numerically
study large quantum spin systems. In the stochastic state selection method we
make a sampling which is simultaneous for many states. This feature enables us
to modify the method so that a number of given constraints are satisfied in
each sampling. In this paper we discuss this modified stochastic state
selection method that will be called the constrained stochastic state selection
method in distinction from the previously proposed one (the conventional
stochastic state selection method) in this paper. We argue that in virtue of
the constrained sampling some quantities obtained in each sampling become more
reliable, i.e. their statistical fluctuations are less than those from the
conventional stochastic state selection method. In numerical calculations of
the spin-1/2 quantum Heisenberg antiferromagnet on a 36-site triangular lattice
we explicitly show that data errors in our estimation of the ground state
energy are reduced. Then we successfully evaluate several low-lying energy
eigenvalues of the model on a 48-site lattice. Our results support that this
system can be described by the theory based on the spontaneous symmetry
breaking in the semiclassical Neel ordered antiferromagnet.


title:
Angular dependence of resistivity in the superconducting state of
  NdFeAsO$_{0.82}$F$_{0.18}$ single crystals

abstract:
  We report the results of angle dependent resistivity of
NdFeAsO$_{0.82}$F$_{0.18}$ single crystals in the superconducting state. By
doing the scaling of resistivity within the frame of the anisotropic
Ginzburg-Landau theory, it is found that the angle dependent resistivity
measured under different magnetic fields at a certain temperature can be
collapsed onto one curve. As a scaling parameter, the anisotropy $\Gamma$ can
be determined for different temperatures. It is found that $\Gamma(T)$
increases slowly with decreasing temperature, varying from $\Gamma \simeq$ 5.48
at T=50 K to $\Gamma \simeq$ 6.24 at T=44 K. This temperature dependence can be
understood within the picture of multi-band superconductivity.


title: Accurate calculations of Sr properties for a high-accuracy optical clock

abstract:
  We have carried out calculations towards the goal of reducing the inaccuracy
of the Sr optical atomic clock to 1$\times10^{-17}$ and below. We calculated
a.c. polarizabilities of the $5s^2 ^1S_0$ and $5s5p ^3P_0^o$ clock states that
are important for reducing the uncertainty of blackbody radiation-induced
frequency shifts for the $^1S_0 - ^3P_0^o$ clock transition. We determined four
low-lying even-parity states whose total contribution to the static
polarizability of the $^3P_0^o$ clock state is at the level of 90%. We show
that if the contribution of these states is experimentally known with 0.1%
accuracy, the same accuracy can be achieved for the total polarizability of the
$^3P_0^o$ state. The corresponding uncertainty for the blackbody shift at a
fixed room temperature will be below 1$\times10^{-17}$. The calculations are
confirmed by a number of experimental measurements on various Sr properties.


title:
Electromagnetic energy-momentum equation without tensors: a geometric
  algebra approach

abstract:
  In this paper, we define energy-momentum density as a product of the complex
vector electromagnetic field and its complex conjugate. We derive an equation
for the spacetime derivative of the energy-momentum density. We show that the
scalar and vector parts of this equation are the differential conservation laws
for energy and momentum, and the imaginary vector part is a relation for the
curl of the Poynting vector. We can show that the spacetime derivative of this
energy-momentum equation is a wave equation. Our formalism is
Dirac-Pauli-Hestenes algebra in the framework of Clifford (Geometric) algebra
Cl_{4,0}.


title: Interaction with a field: a simple integrable model with backreaction

abstract:
  The classical model of an oscillator linearly coupled to a string captures,
for a low price in technique, many general features of more realistic models
for describing a particle interacting with a field or an atom in a
electromagnetic cavity. The scattering matrix and the asymptotic in and out
waves on the string can be computed exactly and the phenomenon of resonant
scattering can be introduced in the simplest way. The dissipation induced by
the coupling of the oscillator to the string can be studied completely. In the
case of a d'Alembert string, the backreaction leads to an
Abraham-Lorentz-Dirac-like equation. In the case of a Klein-Gordon string, one
can see explicitely how radiation governs the (meta)stability of the
(quasi)bounded mode.


title:
Indirect control of quantum system via accessor: pure coherent control
  without system excitation

abstract:
  A pure indirect control of quantum systems via quantum accessor is
investigated. In this control scheme, we do not apply any external classical
excitation fields on the controlled system and we control a quantum system via
a quantum accessor and classical control fields control the accessor only.
Complete controllability is investigated for arbitrary finite dimensional
quantum systems and exemplified by 2 and 3 dimensional systems. The scheme
exhibits some advantages; it uses less qubits in accessor and does not depend
on the energy-level structure of the controlled system.


title:
Magnetic-field asymmetry of electron wave packet transmission in bent
  channels capacitively coupled to a metal gate

abstract:
  We study the electron wave packet moving through a bent channel. We
demonstrate that the packet transmission probability becomes an uneven function
of the magnetic field when the electron packet is capacitively coupled to a
metal plate. The coupling occurs through a non-linear potential which
translates a different kinetics of the transport for opposite magnetic field
orientations into a different potential felt by the scattered electron.


title:
A neutron diffraction study of macroscopically entangled proton states
  in the high temperature phase of the KHCO3 crystal at 340 K

abstract:
  We utilize single-crystal neutron diffraction to study the $C2/m$ structure
of potassium hydrogen carbonate (KHCO$_3$) and macroscopic quantum entanglement
above the phase transition at $T_c = 318$ K. Whereas split atom sites could be
due to disorder, the diffraction pattern at 340 K evidences macroscopic proton
states identical to those previously observed below $T_c$ by F. Fillaux et al.,
(2006 \textit{J. Phys.: Condens. Matter} \textbf{18} 3229). We propose a
theoretical framework for decoherence-free proton states and the calculated
differential cross-section accords with observations. The structural transition
occurs from one ordered $P2_1/a$ structure ($T < T_c$) to another ordered
$C2/m$ structure. There is no breakdown of the quantum regime. It is suggested
that the crystal is a macroscopic quantum object which can be represented by a
state vector. Raman spectroscopy and quasi-elastic neutron scattering suggest
that the $|C2/m>$ state vector is a superposition of the state vectors for two
$P2_1/a$-like structures symmetric with respect to $(a,c)$ planes.


title:
Minimal Lagrangian surfaces in the tangent bundle of a Riemannian
  surface

abstract:
  Given an oriented Riemannian surface $(\Sigma, g)$, its tangent bundle
$T\Sigma$ enjoys a natural pseudo-K\"{a}hler structure, that is the combination
of a complex structure $\J$, a pseudo-metric $\G$ with neutral signature and a
symplectic structure $\Om$. We give a local classification of those surfaces of
$T\Sigma$ which are both Lagrangian with respect to $\Om$ and minimal with
respect to $\G$. We first show that if $g$ is non-flat, the only such surfaces
are affine normal bundles over geodesics. In the flat case there is, in
contrast, a large set of Lagrangian minimal surfaces, which is described
explicitly. As an application, we show that motions of surfaces in $\R^3$ or
$\R^3_1$ induce Hamiltonian motions of their normal congruences, which are
Lagrangian surfaces in $T\S^2$ or $T \H^2$ respectively. We relate the area of
the congruence to a second-order functional $\mathcal{F}=\int \sqrt{H^2-K} dA$
on the original surface.


title:
Nonlocal protons and deuterons opposed to disorder: a single-crystal
  neutron diffraction study of KH0.76D0.24CO3 and a theoretical framewok

abstract:
  We show with neutron diffraction that a single-crystal of potassium hydrogen
deuterium carbonate at room temperature, namely KH$_{0.76}$D$_{0.24}$CO$_3$, is
isomorphous with the KHCO$_3$ and KDCO$_3$ derivatives. Protons and deuterons
are not disordered particles located at definite sites and Bragg peaks are best
fitted with separate H and D sublattices. We propose a theoretical framework
for nonlocal observables and macroscopic states compatible with the crystal
field.


title:
Wounded quark-diquark model predictions for heavy ion collisions at the
  LHC

abstract:
  The ratios of particle densities in lead-lead and proton-lead collisions to
particle density in proton-proton collision in the central rapidity region at
the LHC energy are predicted on the basis of wounded quark-diquark model.


title: Casimir scaling in G(2) lattice gauge theory

abstract:
  We computed potentials between static color sources from the six lowest
representations of G(2) lattice gauge theory, in numerical simulations with the
Wilson action on asymmetric lattices with nonperturbatively estimated values of
the bare anisotropy. We present evidence for (approximate) Casimir scaling of
the obtained intermediate string tensions. The agreement with the
Casimir-scaling prediction improves by increasing the coupling beta in the
weak-coupling region above the crossover observed in G(2) gauge theory. The
result naturally fits into confinement models with magnetic disorder and vacuum
domain structure, but may represent a challenge for other approaches.


title:
Thermodynamics of a one-dimensional frustrated spin-1/2 Heisenberg
  ferromagnet

abstract:
  We calculate the thermodynamic quantities (correlation functions <S_0S_n>,
correlation length xi, spin susceptibility chi, and specific heat C_V) of the
frustrated one-dimensional spin-half J2-J2 Heisenberg ferromagnet, i.e. for J2<
0.25|J1|, using a rotation-invariant Green's-function formalism and full
diagonalization of finite lattices. We find that the critical indices are not
changed by J2, i.e., chi = y_0 T^{-2} and xi = x_0 T^{-1} at T \to 0. However,
the coefficients y_0 and x_0 linearly decrease with increasing J2 according to
the relations y_0=(1-4J_2/|J_1|)/24 and x_0 =(1-4J_2/|J_1|)/4, i.e., both
coefficients vanish at J2=0.25|J1| indicating the zero-temperature phase
transition that is accompanied by a change of the low-temperature behavior of
chi (xi) from chi \propto T^{-2} (xi \propto T^{-1}) at J2 < 0.25|J1| to chi
\propto T^{-3/2} (xi \propto T^{-1/2}) at J2 = 0.25|J1|. In addition, we detect
the existence of an additional low-temperature maximum in the specific heat
when approaching the critical point at J2=0.25|J1|.


title: Causal hydrodynamics and the membrane paradigm

abstract:
  We obtain the relaxation time for the shear viscous stress for various
geometries using the "membrane paradigm" formula proposed recently. We consider
the generic Schwarzschild-AdS black holes (SAdS), the generic Dp-brane, the
Klebanov-Tseytlin (KT) geometry, and the N=2* theory. The formula is the "shear
mode" result and is not fully trustable, but it may be helpful to learn some
generic behaviors about the relaxation time. For example, a simple formula
summarizes all known results for SAdS, and a single expression summarizes the
results for the Dp-brane and the KT geometry.


title: When teaching: Out with magnitudes, in with monochromatic luminosities!

abstract:
  The goal of this document is to illustrate that teaching the concepts of
magnitudes is a needless complication in introductory astronomy courses, and
that use of monochromatic luminosities, rather than arbitrarily defined
magnitudes, leads to a large gain in transparency. This illustration is done
through three examples: the Hertzsprung-Russell diagram, the cosmic distance
ladder, and interstellar reddening. I provide conversion equations from the
magnitude-based to the luminosity-based system; a brief discussion; and a
reference to sample lecture notes.
  I suggest that we, astronomers in the 21st century, abolish magnitudes and
instead use (apparent) monochromatic luminosities in non-specialist teaching.
Given the large gain in transparency I further propose that we seriously
consider using (apparent) monochromatic luminosities also in research papers,
bringing optical astronomy in line with astronomy at other wavelengths.
Comments are welcome.


title: String theory implications on causal hydrodynamics

abstract:
  We summarize the main lessons for causal hydrodynamics/second order
hydrodynamics/Israel-Stewart theory from string theory.


title: Polymers with self-attraction and stiffness: a generic phase structure

abstract:
  Recently it has been shown that a two-dimensional model of self-attracting
polymers based on attracting segments displays two phase transitions, a
theta-like collapse between swollen polymers and a globular state and another
between the globular state and a polymer crystal. On the other hand, the
canonical model based on attracting monomers on lattice sites displays only
one: the standard tricritical theta collapse transition. Here we show that by
considering both models with the addition of stiffness the two models display
the same generic phase diagram. In fact we claim that any two-dimensional model
of a self-attracting single polymer in solution based upon a fully
volume-excluded backbone with isotropic short range attraction should show this
same phase structure. We point to the model of hydrogen bonded polymers to
demonstrate this observation. In three dimensions we note that more than one
crystalline phase may occur.


title:
Surface roughness influence on parametric amplification of
  nanoresonators in presence of thermomechanical and environmental noise

abstract:
  We investigate the surface roughness influence on the gain from parametric
amplification in nanoresonators in presence of thermomechanical and momentum
exchange noise. The roughness is characterized by the rms amplitude w, the
correlation length X, and the roughness exponent 0<H<1. It is found that the
gain strongly increases with increasing roughening (decreasing H and/or
increasing ratio w/ X) due to increment of capacitive coupling, which plays
dominant role when the intrinsic quality factor Qin is comparable or lower than
the quality factor Qgas due to gas collisions. However, for Qin>>Qgas, the
influence of surface roughness on the gain strongly diminishes.


title: The LHC as a Nucleus-Nucleus Collider

abstract:
  This paper begins with a summary of the status of the Large Hadron Collider
at CERN, including the lead-ion injector chain and the plans for the first
phases of commissioning and operation with colliding proton beams. In a later
phase, the LHC will collide lead nuclei at centre-of-mass energies of 5.5 TeV
per colliding nucleon pair. This leap to 28 times beyond what is presently
accessible will open up a new regime, not only in the experimental study of
nuclear matter, but also in the beam physics of hadron colliders.
Ultraperipheral and hadronic interactions of highly-charged beam nuclei will
cause beam losses that dominate the luminosity decay and may quench
superconducting magnets, setting upper limits on luminosity and stored beam
current. Lower limits are set by beam instrumentation. On the other hand,
coherent radiation by the nuclear charges should provide natural cooling to
overcome intra-beam scattering. As with protons, a flexible, staged approach to
full performance will test the limits and make optimal use of scheduled beam
time.


title: The entire-sky catalog of isolated galaxies selected from 2MASS

abstract:
  We present a first entire-sky catalog of isolated galaxies obtained via
systematic automated and visual inspections of extended sources from the Two
Micron All-Sky Survey (2MASS). Based on the Karachentseva's (1973) isolation
criteria, we have extracted a sample of 2100 2MIG galaxies consisting a 4%
fraction among galaxies brighter than K = 12m. Being the objects with probably
no major perturbations in some last billion years, the 2MIG galaxies may be
considered as a reference sample to study environment effects in galaxy
structure and evolution. The 2MIG catalog may also be useful to explore the
existence of dark galaxy population within a volume of z=0.02.


title: A practical guide to unravel time-like transition form factors

abstract:
  A method to determine masses, widths and coupling constants of vector mesons,
like phi(1020), omega(782) and rho0(770) recurrences is defined. Starting from
data on decay rates and cross sections for the processes: phi -> M_I gamma, phi
-> M_I e+e- and e+e- -> M_I phi, where M_I is a pseudoscalar or scalar meson
with isospin I=0,1, the time-like transition form factors, which describe the
vertex phi-gamma-M_I, are parametrized using a vector meson-propagators
description in the low energy region <3-4 GeV, the quark-counting rule
prescription for the high energy behavior, and the analyticity imposed by means
of the dispersion relations.


title:
Transport Properties of an Interacting Quantum Dot with a Non-Uniform
  Magnetization

abstract:
  We study the influence of the non-homogeneity of a magnetization field on the
behaviour of interacting electrons in a quantum dot. In particular we
investigate the magnetotransport properties when the dot is weakly coupled to
two ferromagnetic leads. We take into account the interactions in the quantum
dot non-perturbatively. For a magnetization which varies slowly on the scale of
the Fermi wave length, the non-homogeneity effect is described by a gauge
potential that can be treated perturbatively.


title:
Electron-hole Asymmetry and Quantum Critical Point in Hole-doped
  BaFe$_2$As$_2$

abstract:
  We show, from first-principles calculations, that the hole-doped side of
FeAs-based compounds is different from its electron-doped counterparts. The
electron side is characterized as Fermi surface nesting, and SDW-to-NM quantum
critical point (QCP) is realized by doping. For the hole-doped side, on the
other hand, orbital-selective partial orbital ordering develops together with
checkboard antiferromagnetic (AF) ordering without lattice distortion. A unique
SDW-to-AF QCP is achieved, and $J_2$=$J_1/2$ criteria (in the approximate
$J_1&J_2$ model) is satisfied. The observed superconductivity is located in the
vicinity of QCP for both sides.


title: Lattice QCD 2007

abstract:
  I review the current status of Lattice QCD calculations and the progress that
we have made in consolidating the 'lattice QCD revolution' of four years ago.
Significant results from formalisms other than the improved staggered
formalism, which has been leading the revolution, are now appearing. Comparison
between formalisms gives additional confidence in the results. More precision
tests against experiment have been made and predictions that are needed by the
experimental programme have been improved. There has been particular progress
this year in charm and strange physics.


title:
Notes on De Jong's period=index theorem for central simple algebras over
  fields of transcendence degree two

abstract:
  These are notes on de Jong's proof of the period=index theorem over fields of
transcendence degree two. They are actually about the simplified proof sketched
by de Jong in the last section of his paper. These notes were meant as support
for my lectures at the summer school "Central Simple Algebras over Function
Fields" at the Universitat Konstanz between August, 26 and September, 1 2007
(other lectures on this subject were given by Philippe Gille, Andrew Kresch,
Max Lieblich, Tamas Szamuely and Jan Van Geel).
  No originality is intended (except perhaps a little in the proof of the Artin
splitting theorem). Various sources on which the material is based are
indicated in the notes.
  The reader should be warned that these notes have not been updated to reflect
developments in the subject which occurred after the end of the summerschool.


title: Large regular QCD coupling at Low Energy?

abstract:
  The issue is the expediency of the QCD notions use in the low energy region
down to the confinement scale, and, in particular, the efficacy of the QCD
invariant coupling \bar{\alpha}_s(Q^2) with a minimal analytic modification in
this domain. To this goal, we overview a quite recent progress in application
of the ghost-free Analytic Perturbative Theory approach (with no adjustable
parameters) for QCD in the region below 1 GeV. Among them the Bethe--Salpeter
analysis of the meson spectra and spin-dependent (polarization) Bjorken sum
rule. The impression is that there is a chance for the theoretically consistent
and numerically correlated description of hadronic events from Z_0 till a few
hundred MeV scale by combination of analytic pQCD and some explicit
non-perturbative contribution in the spirit of duality. This is an invitation
to the practitioner community for a more courageous use of ghost-free QCD
coupling models for data analysis in the low energy region.


title: Spontaneous spin accumulation in singlet-triplet Josephson junctions

abstract:
  We study the Andreev bound states in a Josephson junction between a singlet
and a triplet superconductors. Because of the mismatch in the spin symmetries
of pairing, the energies of the spin up and down quasiparticles are generally
different. This results in imbalance of spin populations and net spin
accumulation at the junction in equilibrium. This effect can be detected using
probes of local magnetic field, such as the scanning SQUID, Hall, and Kerr
probes. It may help to identify potential triplet pairing in $\rm(TMTSF)_2X$,
$\rm Sr_2RuO_4$, and oxypnictides.


title: Markovian Approximation for the Nos\'e--Hoover method and H-theorem

abstract:
  A Langevin equation with state-dependent random force is considered. When the
Helmholtz free energy is a nonincreasing function of time (the H-theorem), a
generalized Einstein relation is obtained. A stochastic process of the
Nos\'e--Hoover method is discussed on the basis of the Markovian approximation.
It is found that the generalized Einstein relation holds for the Fokker--Planck
equation associated with the stochastic Nos\'e--Hoover equation. The present
result indicates that the Nos\'e--Hoover dynamics coarse-grained with time
satisfies the H-theorem and therefore works as a heat bath.


title: The Regular C*-algebra of an Integral Domain

abstract:
  To each integral domain R with finite quotients we associate a purely
infinite simple C*-algebra in a very natural way. Its stabilization can be
identified with the crossed product of the algebra of continuous functions on
the "finite adele space" corresponding to R by the action of the ax+b-group
over the quotient field Q(R). We study the relationship to generalized
Bost-Connes systems and deduce for them a description as universal C*-algebras
with the help of our construction.


title: A New Era of Leptogenesis

abstract:
  This thesis is devoted to some forefront issues in the field of leptogenesis.
After reviewing the simplest picture where flavor effects are neglected and
only the lightest right-handed neutrino contributes to the generation of
asymmetry, we discuss in detail the importance of flavor effects, the possible
relevance of quantum effects, as well as the role played by the heavier
right-handed neutrinos.


title:
Conditional preparation of single photons using parametric
  downconversion: A recipe for purity

abstract:
  In an experiment reported recently [Phys. Rev. Lett. 100, 133601 (2008)], we
demonstrated that, through group velocity matched parametric downconversion,
heralded single photons can be generated in pure quantum states without
spectral filtering. The technique relies on factorable photon pair production,
initially developed theoretically in the strict collinear regime; focusing -
required in any experimental implementation - can ruin this factorability. Here
we present the numerical model used to design our single photon sources and
minimize spectral correlations in the light of such experimental
considerations. Furthermore, we show that the results of our model are in good
agreement with measurements made on the photon pairs and give a detailed
description of the exact requirements for constructing this type of source.


title:
Cold performance tests of blocked-impurity-band Si:As detectors
  developed for DARWIN

abstract:
  We report first results of laboratory tests of Si:As blocked-impurity-band
(BIB) mid-infrared (4 to 28 um) detectors developed by IMEC. These prototypes
feature 88 pixels hybridized on an integrated cryogenic readout electronics
(CRE). They were developed as part of a technology demonstration program for
the future DARWIN mission. In order to be able to separate detector and readout
effects, a custom build TIA circuitry was used to characterize additional
single pixel detectors. We used a newly designed test setup at the MPIA to
determine the relative spectral response, the quantum efficiency, and the dark
current. All these properties were measured as a function of operating
temperature and detector bias. In addition the effects of ionizing radiation on
the detector were studied. For determining the relative spectral response we
used a dual-grating monochromator and a bolometer with known response that was
operated in parallel to the Si:As detectors. The quantum efficiency was
measured by using a custom-build high-precision vacuum black body together with
cold (T ~ 4 K) filters of known (measured) transmission.


title:
A uniqueness result for Kirchhoff equations with non-Lipschitz nonlinear
  term

abstract:
  We consider the second order Cauchy problem $$u''+\m{u}Au=0, u(0)=u_{0},
u'(0)=u_{1},$$ where $m:[0,+\infty)\to[0,+\infty)$ is a continuous function,
and $A$ is a self-adjoint nonnegative operator with dense domain on a Hilbert
space.
  It is well known that this problem admits local-in-time solutions provided
that $u_{0}$ and $u_{1}$ are regular enough, depending on the continuity
modulus of $m$. It is also well known that the solution is unique when $m$ is
locally Lipschitz continuous.
  In this paper we prove that if either $<Au_{0},u_{1}>\neq 0$, or
$|A^{1/2}u_{1}|^{2}\neq\m{u_{0}}|Au_{0}|^{2}$, then the local solution is
unique even if $m$ is not Lipschitz continuous.


title: Quantum Query Complexity of Multilinear Identity Testing

abstract:
  Motivated by the quantum algorithm in \cite{MN05} for testing commutativity
of black-box groups, we study the following problem: Given a black-box finite
ring $R=\angle{r_1,...,r_k}$ where $\{r_1,r_2,...,r_k\}$ is an additive
generating set for $R$ and a multilinear polynomial $f(x_1,...,x_m)$ over $R$
also accessed as a black-box function $f:R^m\to R$ (where we allow the
indeterminates $x_1,...,x_m$ to be commuting or noncommuting), we study the
problem of testing if $f$ is an \emph{identity} for the ring $R$. More
precisely, the problem is to test if $f(a_1,a_2,...,a_m)=0$ for all $a_i\in R$.
  We give a quantum algorithm with query complexity $O(m(1+\alpha)^{m/2}
k^{\frac{m}{m+1}})$ assuming $k\geq (1+1/\alpha)^{m+1}$. Towards a lower bound,
we also discuss a reduction from a version of $m$-collision to this problem.
  We also observe a randomized test with query complexity $4^mmk$ and constant
success probability and a deterministic test with $k^m$ query complexity.


title:
Almost Sure Stabilization for Adaptive Controls of Regime-switching LQ
  Systems with A Hidden Markov Chain

abstract:
  This work is devoted to the almost sure stabilization of adaptive control
systems that involve an unknown Markov chain. The control system displays
continuous dynamics represented by differential equations and discrete events
given by a hidden Markov chain. Different from previous work on stabilization
of adaptive controlled systems with a hidden Markov chain, where average
criteria were considered, this work focuses on the almost sure stabilization or
sample path stabilization of the underlying processes. Under simple conditions,
it is shown that as long as the feedback controls have linear growth in the
continuous component, the resulting process is regular. Moreover, by
appropriate choice of the Lyapunov functions, it is shown that the adaptive
system is stabilizable almost surely. As a by-product, it is also established
that the controlled process is positive recurrent.


title:
Describing Sr2RuO4 superconductivity in a generalized Ginzburg--Landau
  theory

abstract:
  We propose a simple explanation of unconventional thermodynamical and
magnetic properties observed for Sr2RuO4. Actually, our two-phase model of
superconductivity, based on a straight generalization of the Ginzburg-Landau
theory, does predict two jumps in the heat capacity as well as a double curve
for the dependence of the critical temperature on an external magnetic field.
Such theoretical previsions well agree with the currently available
experimental data for Sr2RuO4


title: Towards a kinetic theory for fermions with quantum coherence

abstract:
  A new density matrix and corresponding quantum kinetic equations are
introduced for fermions undergoing coherent evolution either in time (coherent
particle production) or in space (quantum reflection). A central element in our
derivation is finding new spectral solutions for the 2-point Green's functions
written in the Wigner representation, that are carrying the information of the
quantum coherence. Physically observable density matrix is then defined from
the bare singular 2-point function by convoluting it with the extrenous
information about the state of the system. The formalism is shown to reproduce
familiar results from the Dirac equation approach, like Klein problem and
nonlocal reflection from a mass wall. The notion of the particle number in the
presence of quantum coherence is shown to be particularily transparent in the
current picture. We extend the formalism to the case of mixing fields and show
how the usual flavour mixing and oscillation of neutrinos emerges again from a
singular shell structure. Finally, we show how the formalism can be extended to
include decohering interactions.


title:
A Generalized Mixed Zero-sum Stochastic Differential Game and Double
  Barrier Reflected BSDEs with Quadratic Growth Coefficient

abstract:
  This article is dedicated to the study of mixed zero-sum two-player
stochastic differential games in the situation when the player's cost
functionals are modeled by doubly controlled reflected backward stochastic
equations with two barriers whose coefficients have quadratic growth in Z. This
is a generalization of the risk-sensitive payoffs. We show that the lower and
the upper value function associated with this stochastic differential game with
reflection are deterministic and they are also the unique viscosity solutions
for two Isaacs equations with obstacles.


title:
Vector-axialvector mixing from a chiral effective field theory at finite
  temperature

abstract:
  We study the vector-axialvector mixing in a hot medium and its evolution
toward the chiral phase transition using different symmetry restoration
scenarios based on the generalized hidden local symmetry framework. We show
that the presence of the $a_1$ meson reduces the vector spectral function
around $\rho$ meson mass and enhances it around $a_1$ meson mass. The coupling
strength of $a_1$ to $\rho$ and $\pi$ vanishes at the critical temperature due
to the degenerate $\rho$-$a_1$ masses. This feature holds rigorously in the
chiral limit and still stays intact to good approximation for the physical pion
mass.


title: Review on epsilon'/epsilon

abstract:
  Experiments at CERN and Fermilab have been competing each other to improve
the measurement of a CP violation parameter, epsilon'/epsilon. Fermilab
KTeV-E832 recently announced their final result, Re(epsilon'/epsilon) = [19.2
+- 2.1] x 10^{-4}. The new world average shows the existence of direct CP
violation in the decay process itself with 12 standard deviations.


title: On the spectrum of a bent chain graph

abstract:
  We study Schr\"odinger operators on an infinite quantum graph of a chain form
which consists of identical rings connected at the touching points by
$\delta$-couplings with a parameter $\alpha\in\R$. If the graph is "straight",
i.e. periodic with respect to ring shifts, its Hamiltonian has a band spectrum
with all the gaps open whenever $\alpha\ne 0$. We consider a "bending"
deformation of the chain consisting of changing one position at a single ring
and show that it gives rise to eigenvalues in the open spectral gaps. We
analyze dependence of these eigenvalues on the coupling $\alpha$ and the
"bending angle" as well as resonances of the system coming from the bending. We
also discuss the behaviour of the eigenvalues and resonances at the edges of
the spectral bands.


title: Delayed Recombination and Cosmic Parameters

abstract:
  Current cosmological constraints from Cosmic Microwave Background (CMB)
anisotropies are typically derived assuming a standard recombination scheme,
however additional resonance and ionizing radiation sources can delay
recombination, altering the cosmic ionization history and the cosmological
inferences drawn from CMB data. We show that for recent observations of CMB
anisotropy, from the Wilkinson Microwave Anisotropy Probe satellite mission
5-year survey (WMAP5) and from the ACBAR experiment, additional resonance
radiation is nearly degenerate with variations in the spectral index, n_s, and
has a marked effect on uncertainties in constraints on the Hubble constant, age
of the universe, curvature and the upper bound on the neutrino mass. When a
modified recombination scheme is considered, the redshift of recombination is
constrained to z_*=1078\pm11, with uncertainties in the measurement weaker by
one order of magnitude than those obtained under the assumption of standard
recombination while constraints on the shift parameter are shifted by 1-sigma
to R=1.734\pm0.028. Although delayed recombination limits the precision of
parameter estimation from the WMAP satellite, we demonstrate that this should
not be the case for future, smaller angular scales measurements, such as those
by the Planck satellite mission.


title: A New Approach to the 3D Faddeev Equation for Three-Body Scattering

abstract:
  A novel approach to solve the Faddeev equation for three-body scattering at
arbitrary energies is proposed. This approach disentangles the complicated
singularity structure of the free three-nucleon propagator leading to the
moving and logarithmic singularities in standard treatments. The Faddeev
equation is formulated in momentum space and directly solved in terms of
momentum vectors without employing a partial wave decomposition. In its
simplest form the Faddeev equation for identical bosons, which we are using, is
an integral equation in five variables, magnitudes of relative momenta and
angles. The singularities of the free propagator and the deuteron propagator
are now both simple poles in two different momentum variables, and thus can
both be integrated with standard techniques.


title: New two-parametric family of exactly solvable Dirac Hamiltonians

abstract:
  We construct a two-parametric family of exactly solvable Dirac Hamiltonians
by the Darboux transformation method. We obtain intertwining relations between
different members of the Hamiltonian family. We investigate the spectral
properties of the obtained Hamiltonians and the explicit forms of their
eigenfunctions.


title: Twinning superlattices in indium phosphide nanowires

abstract:
  Here, we show that we control the crystal structure of indium phosphide (InP)
nanowires by impurity dopants. We have found that zinc decreases the activation
barrier for 2D nucleation growth of zinc-blende InP and therefore promotes the
InP nanowires to crystallise in the zinc blende, instead of the commonly found
wurtzite crystal structure. More importantly, we demonstrate that we can, by
controlling the crystal structure, induce twinning superlattices with
long-range order in InP nanowires. We can tune the spacing of the superlattices
by the wire diameter and the zinc concentration and present a model based on
the cross-sectional shape of the zinc-blende InP nanowires to quantitatively
explain the formation of the periodic twinning.


title:
Near-Infrared Imaging Polarimetry of M42: Aperture Polarimetry of
  Point-like Sources

abstract:
  We have conducted aperture polarimetry of ~500 stars of the Orion Nebula
Cluster (ONC) in M42 based on our wide-field (~8'\times 8') $JHKs$ band
polarimetry.
  Most of the near-infrared (NIR) polarizations are dichroic, with position
angles of polarization agreeing, both globally and locally, with previous
far-infrared (FIR) and submillimeter observations, having taken into account
the 90$^\circ $ difference in angles between dichroic absorption and emission.
This is consistent with the idea that both NIR dichroic polarizations and
FIR/submillimeter thermal polarizations trace the magnetic fields in the OMC-1
region. The magnetic fields inferred from these observations show a pinch at
scales less than 0.5 pc with a centroid near IRc2. The hourglass-shaped
magnetic field pattern is explained by the models in which the magnetic field
lines are dragged along with the contracting gas and then wound up by rotation
in a disk. The highly polarized region to the northwest of IRc2 and the
low-polarized region near the bright bar are also common among NIR and
FIR/submillimeter data, although a few regions of discrepancy exist.
  We have also discerned ~50 possible highly polarized sources whose
polarizations are more likely to be intrinsic rather than dichroic. Their
polarization efficiencies ($P(H)/A(H)$) are too large to be explained by the
interstellar polarization. These include 10 young brown dwarfs that suggest a
higher polarization efficiency, which may present geometrical evidence for
(unresolved) circumstellar structures around young brown dwarfs.


title: Motion of dust in mean-motion resonances with planets

abstract:
  Effect of stellar electromagnetic radiation on motion of spherical dust
particle in mean-motion orbital resonances with a planet is investigated.
Planar circular restricted three-body problem with the Poynting-Robertson (P-R)
effect yields monotonous secular evolution of eccentricity when the particle is
trapped in the resonance. Elliptically restricted three-body problem with the
P-R effect enables nonmonotonous secular evolution of eccentricity and the
evolution of eccentricity is qualitatively consistent with the published
results for the complicated case of interaction of electromagnetic radiation
with nonspherical dust grain. Thus, it is sufficient to allow either nonzero
eccentricity of the planet or nonsphericity of the grain and the orbital
evolutions in the resonances are qualitatively equal for the two cases. This
holds both for exterior and interior mean-motion orbital resonances. Evolutions
of longitude of pericenter in the planar circular and elliptical restricted
three-body problems are shown. Our numerical integrations suggest that any
analytic expression for secular time derivative of the particle's longitude of
pericenter does not exist, if a dependence on semi-major axis, eccentricity and
longitude of pericenter is considered (the P-R effect and mean-motion resonance
with the planet in circular orbit is taken into account).
  Change of optical properties of the spherical grain with the heliocentric
distance is also considered. The change of the optical properties: i) does not
have any significant influence on secular evolution of eccentricity, ii) causes
that the shift of pericenter is mainly in the same direction/orientation as the
particle motion around the Sun. The statements hold both for circular and
noncircular planetary orbits.


title: Barabasi Queueing Model and Invasion Percolation on a tree

abstract:
  In this paper we study the properties of the Barab\'asi model of queueing
under the hypothesis that the number of tasks is steadily growing in time. We
map this model exactly onto an Invasion Percolation dynamics on a Cayley tree.
This allows to recover the correct waiting time distribution $P_W(\tau)\sim
\tau^{-3/2}$ at the stationary state (as observed in different realistic data)
and also to characterize it as a sequence of causally and geometrically
connected bursts of activity. We also find that the approach to stationarity is
very slow.


title: Search for Light CP-odd Higgs in Radiative Decays of Upsilon(1S)

abstract:
  We search for a non-SM-like CP-odd Higgs boson (a0_1) with m(a0_1)< 2m(b) in
radiative decays of the Upsilon(1S), using 21.5M Upsilon(1S) mesons directly
produced in e+e- annihilation. We investigate a0_1 --> tau+tau- and a0_1 -->
mu+mu- decay channels. No significant signal is found. We obtain upper limits
on the product of B(Upsilon(1S)-->gamma a0_1) and B(a0_1-->tau+tau-) or
B(a0_1-->mu+mu-). Our tau+tau- results are almost two orders of magnitude more
stringent than previous upper limits. Our data provide no evidence for a Higgs
state with a mass of 214 MeV decaying to mu+mu-. Existence of such a state was
previously proposed as an explanation for 3 Sigma+ --> p mu+mu- events, having
mu+mu- masses just above the kinematic threshold, observed by the HyperCP
experiment. Our results constrain NMSSM models.


title:
The seismogenic area in the lithosphere considered as an "Open Physical
  System". Its implications on some seismological aspects. Part - III. Seismic
  Potential

abstract:
  The seismic potential of any regional seismogenic area is analyzed in terms
of the "open physical system" inflow - outflow energy balance model
(Thanassoulas, 2008, Part - I). Following the magnitude determination method
presented by Thanassoulas, (2008, Part - II) any region of any arbitrary area
extent is assumed as being a potential seismogenic region. Consequently, the
capability for the generation of a maximum magnitude future EQ at each virtual
seismogenic region is investigated all over Greece at certain times. The later
results are used to compile maps of the seismic potential / maximum expected EQ
magnitude for Greece at 5 year's intervals ranging from 1970 to 2000. The
comparison of these seismic potential maps / maximum expected EQ magnitude to
the corresponding seismicity (M>6R) for each corresponding 5 years period
reveals their tight interrelation. Therefore, the calculated seismic potential
/ maximum expected EQ magnitude, due to its drastic change in time in any
seismogenic region, is a dynamic in time parameter which indicates the seismic
energy charge status of each seismogenic area.


title: The Weil--Petersson geometry of the moduli space of Riemann surfaces

abstract:
  In [4], Z. Huang showed that in the thick part of the moduli space
$\mathcal{M}_g$ of compact Riemann surfaces of genus $g$, the sectional
curvature of the Weil--Petersson metric is bounded below by a constant
depending on injectivity radius, but independent of the genus $g$. In this
article, we prove this result by a different method. We also show that the same
result holds for Ricci curvature. For the universal Teichm\"uller space
equipped with Hilbert structure induced by Weil--Petersson metric, we prove
that its sectional curvature is bounded below by a universal constant.