title: On the moduli space of semilocal strings and lumps

abstract:
  We study BPS non-abelian semilocal vortices in U(Nc) gauge theory with Nf
flavors, Nf > Nc, in the Higgs phase. The moduli space for arbitrary winding
number is described using the moduli matrix formalism. We find a relation
between the moduli spaces of the semilocal vortices in a Seiberg-like dual
pairs of theories, U(Nc) and U(Nf-Nc). They are two alternative regularizations
of a "parent" non-Hausdorff space, which tend to the same moduli space of
sigma-model lumps in the infinite gauge coupling limits. We examine the
normalizability of the zero-modes and find the somewhat surprising phenomenon
that the number of normalizable zero-modes, dynamical fields in the effective
action, depends on the point of the moduli space we are considering. We find,
in the lump limit, an effective action on the vortex worldsheet, which we
compare to that found by Shifman and Yung.


title: Pseudo-Hermiticity of an Exactly Solvable Two-Dimensional Model

abstract:
  We study a two-dimensional exactly solvable non-Hermitian $PT-$non-symmetric
quantum model with real spectrum, which is not amenable to separation of
variables, by supersymmetrical methods. Here we focus attention on the property
of pseudo-Hermiticity, biorthogonal expansion and pseudo-metric operator. To
our knowledge this is the first time that pseudo-Hermiticity is realized
explicitly for a nontrivial two-dimensional case. It is shown that the
Hamiltonian of the model is not diagonalizable.


title:
Parent Stars of Extrasolar Planets. VIII. Chemical Abundances for 18
  Elements in 31 Stars

abstract:
  We present the results of detailed spectroscopic abundance analyses for 18
elements in 31 nearby stars with planets. The resulting abundances are combined
with other similar studies of nearby stars with planets and compared to a
sample of nearby stars without detected planets. We find some evidence for
abundance differences between these two samples for Al, Si and Ti. Some of our
results are in conflict with a recent study of stars with planets in the SPOCS
database. We encourage continued study of the abundance patterns of stars with
planets to resolve these discrepancies.


title: Observation of the Density Minimum in Deeply Supercooled Confined Water

abstract:
  Small angle neutron scattering (SANS) is used to measure the density of heavy
water contained in 1-D cylindrical pores of mesoporous silica material
MCM-41-S-15, with pores of diameter of 15+-1 A. In these pores the homogenous
nucleation process of bulk water at 235 K does not occur and the liquid can be
supercooled down to at least 160 K. The analysis of SANS data allows us to
determine the absolute value of the density of D2O as a function of
temperature. We observe a density minimum at 210+-5 K with a value of
1.041+-0.003 g/cm3. We show that the results are consistent with the
predictions of molecular dynamics simulations of supercooled bulk water. This
is the first experimental report of the existence of the density minimum in
supercooled water.


title: Marginal deformations in string field theory

abstract:
  We describe a method for obtaining analytic solutions corresponding to exact
marginal deformations in open bosonic string field theory. For the photon
marginal deformation we have an explicit analytic solution to all orders. Our
construction is based on a pure gauge solution where the gauge field is not in
the Hilbert space. We show that the solution itself is nevertheless perfectly
regular. We study its gauge transformations and calculate some coefficients
explicitly. Finally, we discuss how our method can be implemented for other
marginal deformations.


title: Whitehead's Trilogy and the Curvature of Spacetime

abstract:
  My object in the present paper is to: (1) introduce physicists to the life
and work of Whitehead; (2) outline the content of his book "The Principle of
Relativity"; (3) present Whitehead's basic criticism of the General Theory of
Relativity which, to my mind, has never been rebutted or properly appreciated,
even by GTR specialists; (4) propose a significant relevant research problem;
and (5) summarize some of the rather radical implications of the acceptance of
Whitehead's observations, including that spacetime is not curved.


title: Non-Abelian Chern-Simons Vortices

abstract:
  We consider the bosonic sector of a N=2 supersymmetric Chern-Simons-Higgs
theory in 2+1 dimensions. The gauge group is U(1)xU(N) and has N_f flavors of
fundamental matter fields. The model supports non-Abelian (axially symmetric)
vortices when N_f\geq N, which have internal (orientational) moduli. When N_f >
N, the solutions acquire additional collective coordinates parameterizing their
transverse size. We solve the BPS equations numerically and obtain local (N_f =
N) and semi-local (N_f > N) string solutions.


title: Dissipation in graphene and nanotube resonators

abstract:
  Different damping mechanisms in graphene nanoresonators are studied: charges
in the substrate, ohmic losses in the substrate and the graphene sheet,
breaking and healing of surface bonds (Velcro effect), two level systems,
attachment losses, and thermoelastic losses. We find that, for realistic
structures and contrary to semiconductor resonators, dissipation is dominated
by ohmic losses in the graphene layer and metallic gate. An extension of this
study to carbon nanotube-based resonators is presented.


title: The Luminosity Distribution of Globular Clusters in Dwarf Galaxies

abstract:
  The majority of the globular clusters associated with the Sagittarius dwarf
galaxy are faint. In this respect it differs significantly from the globular
cluster systems surrounding typical giant galaxies. The observation that most
of globular clusters in the outer halo of the Galaxy are also sub-luminous may
be understood by assuming that these clusters once also belonged to faint
cluster-rich dwarf systems that were subsequently captured and destroyed by the
Milky Way System.


title: Front propagation into unstable metal nanowires

abstract:
  Long, cylindrical metal nanowires have recently been observed to form and be
stable for seconds at a time at room temperature. Their stability and
structural dynamics is well described by a continuum model, the nanoscale
free-electron model, which predicts cylinders in certain intervals of radius to
be linearly unstable. In this paper, I study how a small, localized
perturbation of such an unstable wire grows exponentially and propagates along
the wire with a well-defined front. The front is found to be pulled, and forms
a coherent pattern behind it. It is well described by a linear marginal
stability analysis of front propagation into an unstable state. In some cases,
nonlinearities of the wire dynamics are found to trigger an invasive mode that
pushes the front. Experimental procedures that could lead to the observation of
this phenomenon are suggested.


title:
The Density Profile of Local Ellipticals as Violently Relaxed,
  Collisionless, Dissipationless Systems

abstract:
  In a series of recent papers, a new formalism has been developed that
explains the inner structure of dark matter halos as collisionless,
dissipationless systems assembled through mergers and accretion at the typical
cosmological rate. Nearby ellipticals are also collisionless, dissipationless
systems assembling their mass through mergers, but contrarily to the former
structures they do not continuously accrete external matter because they are
shielded by their host halos. Here we explore the idea that the infall of their
own matter ejected within the halo on the occasion of a violent merger can play
a role similar to external accretion in halos. The predicted stellar mass
density profile fits the observed one, and the empirical total mass density
profile is also recovered.


title:
Conifold singularities, resumming instantons and non-perturbative mirror
  symmetry

abstract:
  We determine the instanton corrected hypermultiplet moduli space in type IIB
compactifications near a Calabi-Yau conifold point where the size of a
two-cycle shrinks to zero. We show that D1-instantons resolve the conifold
singularity caused by worldsheet instantons. Furthermore, by resumming the
instanton series, we reproduce exactly the results obtained by Ooguri and Vafa
on the type IIA side, where membrane instantons correct the hypermultiplet
moduli space. Our calculations therefore establish that mirror symmetry holds
non-perturbatively in the string coupling.


title: Strings on AdS_2 and the High-Energy Limit of Noncritical M-Theory

abstract:
  Noncritical M-theory in 2+1 dimensions has been defined as a double-scaling
limit of a nonrelativistic Fermi liquid on a flat two-dimensional plane. Here
we study this noncritical M-theory in the limit of high energies, analogous to
the \alpha'\to\infty limit of string theory. In the related case of
two-dimensional Type 0A strings, it has been argued that the conformal
\alpha'\to\infty limit leads to AdS_2 with a propagating fermion whose mass is
set by the value of the RR flux. Here we provide evidence that in the
high-energy limit, the natural ground state of noncritical M-theory similarly
describes the AdS_2\times S^1 spacetime, with a massless propagating fermion.
We argue that the spacetime effective theory in this background is captured by
a topological higher-spin extension of conformal Chern-Simons gravity in 2+1
dimensions, consistently coupled to a massless Dirac field. Intriguingly, the
two-dimensional plane populated by the original nonrelativistic fermions is
essentially the twistor space associated with the symmetry group of the
AdS_2\times S^1 spacetime; thus, at least in the high-energy limit, noncritical
M-theory can be nonperturbatively described as a "Fermi liquid on twistor
space."


title: Pomeranchuk instability: symmetry breaking and experimental signatures

abstract:
  We discuss the emergence of symmetry-breaking {\it via} the Pomeranchuk
instability from interactions that respect the underlying point-group symmetry.
We use a variational mean-field theory to consider a 2D continuum and a square
lattice. We describe two experimental signatures: a symmetry-breaking pattern
of Friedel oscillations around an impurity; and a structural transition.


title: Spontaneous Symmetry Breaking as a Basis of Particle Mass

abstract:
  Electroweak theory joins electromagnetism with the weak force in a single
quantum field theory, ascribing the two fundamental interactions--so different
in their manifestations--to a common symmetry principle. How the electroweak
gauge symmetry is hidden is one of the most urgent and challenging questions
facing particle physics. The provisional answer incorporated in the "standard
model" of particle physics was formulated in the 1960s by Higgs, by Brout &
Englert, and by Guralnik, Hagen & Kibble: The agent of electroweak symmetry
breaking is an elementary scalar field whose self-interactions select a vacuum
state in which the full electroweak symmetry is hidden, leaving a residual
phase symmetry of electromagnetism. By analogy with the Meissner effect of the
superconducting phase transition, the Higgs mechanism, as it is commonly known,
confers masses on the weak force carriers W and Z. It also opens the door to
masses for the quarks and leptons, and shapes the world around us. It is a good
story--though an incomplete story--and we do not know how much of the story is
true. Experiments that explore the Fermi scale (the energy regime around 1 TeV)
during the next decade will put the electroweak theory to decisive test, and
may uncover new elements needed to construct a more satisfying completion of
the electroweak theory. The aim of this article is to set the stage by
reporting what we know and what we need to know, and to set some "Big
Questions" that will guide our explorations.


title:
Bubbling AdS and droplet descriptions of BPS geometries in IIB
  supergravity

abstract:
  This paper focuses on supergravity duals of BPS states in N=4 super
Yang-Mills. In order to describe these duals, we begin with a sequence of
breathing mode reductions of IIB supergravity: first on S^3, then S^3 x S^1,
and finally on S^3 x S^1 x CP^1. We then follow with a complete supersymmetry
analysis, yielding 1/8, 1/4 and 1/2 BPS configurations, respectively (where in
the last step we take the Hopf fibration of S^3). The 1/8 BPS geometries, which
have an S^3 isometry and are time-fibered over a six-dimensional base, are
determined by solving a non-linear equation for the Kahler metric on the base.
Similarly, the 1/4 BPS configurations have an S^3 x S^1 isometry and a
four-dimensional base, whose Kahler metric obeys another non-linear,
Monge-Ampere type equation.
  Despite the non-linearity of the problem, we develop a universal bubbling AdS
description of these geometries by focusing on the boundary conditions which
ensure their regularity. In the 1/8 BPS case, we find that the S^3 cycle
shrinks to zero size on a five-dimensional locus inside the six-dimensional
base. Enforcing regularity of the full solution requires that the interior of a
smooth, generally disconnected five-dimensional surface be removed from the
base. The AdS_5 x S^5 ground state corresponds to excising the interior of an
S^5, while the 1/8 BPS excitations correspond to deformations (including
topology change) of the S^5 and/or the excision of additional droplets from the
base. In the case of 1/4 BPS configurations, by enforcing regularity
conditions, we identify three-dimensional surfaces inside the four-dimensional
base which separate the regions where the S^3 shrinks to zero size from those
where the S^1 shrinks.


title:
Zero-energy states and fragmentation of spin in the easy-plane
  antiferromagnet on a honeycomb lattice

abstract:
  The core of the vortex in the Neel order parameter for an easy-plane
antiferromagnet on honeycomb lattice is demonstrated to bind two zero-energy
states. Remarkably, a single electron occupying this mid-gap band has its spin
fragmented between the two sublattices: Whereas it yields a vanishing total
magnetization it shows a finite Neel order, orthogonal to the one of the
assumed background. The requisite easy-plane anisotropy may be introduced by a
magnetic field parallel to the graphene layer, for example. The results are
relevant for spin-1/2 fermions on graphene's or optical honeycomb lattice, in
the strongly interacting regime.


title:
Swift observations of GRB 060614: an anomalous burst with a well behaved
  afterglow

abstract:
  GRB 060614 is a remarkable GRB observed by Swift with puzzling properties,
which challenge current progenitor models. The lack of any bright SN down to
very strict limits and the vanishing spectral lags are typical of short GRBs,
strikingly at odds with the long (102s) duration of this event. Here we present
spectral and temporal analysis of the Swift observations. We show that the
burst presents standard optical, UV and X-ray afterglows. An achromatic break
is observed simultaneously in optical and X-rays, at a time consistent with the
break in the R-band light curve measured by the VLT. The achromatic behaviour
and the consistent post-break decay slopes make GRB 060614 one of the best
examples of a jet break for a Swift burst. The optical, UV and X-rays afterglow
light curves have also an earlier break at ~30 ks. In the optical, there is
strong spectral evolution around this break, suggesting the passage of a break
frequency through the optical/UV band. The very blue spectrum at early times
and the trend in the light curves (rising at low frequencies, and decaying at
higher energies) suggest this may be the injection frequency. The early X-ray
light curve is well interpreted as the X-ray counterpart of the burst extended
emission. Spectral analysis of BAT/XRT data in the 80s overlap time show that
the Ep of the burst has decreased to as low as 8keV at the beginning of the XRT
observation. The Ep continues to decrease through the XRT energy band and exits
it at about 500s after the trigger. The average Ep of the burst is likely < 24
keV but larger than 8 keV. The initial peak observed by BAT is however
distinctly harder than the rest with Ep ~300 keV as measured by Konus Wind.
Considering the time-averaged spectral properties, GRB 060614 is consistent
with the Eiso-Ep_rest, Egamma-Ep_rest, and Liso-Ep correlations.


title:
Squashed entanglement for multipartite states and entanglement measures
  based on the mixed convex roof

abstract:
  New measures of multipartite entanglement are constructed based on two
definitions of multipartite information and different methods of optimizing
over extensions of the states. One is a generalization of the squashed
entanglement where one takes the mutual information of parties conditioned on
the state's extension and takes the infimum over such extensions. Additivity of
the multipartite squashed entanglement is proved for both versions of the
multipartite information which turn out to be related. The second one is based
on taking classical extensions. This scheme is generalized, which enables to
construct measures of entanglement based on the {\it mixed convex roof} of a
quantity, which in contrast to the standard convex roof method involves
optimization over all decompositions of a density matrix rather than just the
decompositions into pure states. As one of the possible applications of these
results we prove that any multipartite monotone is an upper bound on the amount
of multipartite distillable key. The findings are finally related to analogous
results in classical key agreement.


title: More supersymmetric Wilson loops

abstract:
  We present a large new family of Wilson loop operators in N=4 supersymmetric
Yang-Mills theory. For an arbitrary curve on the three dimensional sphere one
can add certain scalar couplings to the Wilson loop so it preserves at least
two supercharges. Some previously known loops, notably the 1/2 BPS circle,
belong to this class, but we point out many more special cases which were not
known before and could provide further tests of the AdS/CFT correspondence.


title:
The Habitat Segregation between Lyman Break Galaxies and Lyman alpha
  Emitters around a QSO at z~5

abstract:
  We carried out a target survey for Lyman break galaxies (LBGs) and Lyman
alpha emitters (LAEs) around QSO SDSS J0211-0009 at z=4.87. The deep and wide
broadband and narrowband imaging simultaneously revealed the perspective
structure of these two high-z populations. The LBGs without Ly-alpha emission
form a filamentary structure including the QSO, while the LAEs are distributed
around the QSO but avoid it within a distance of ~4.5Mpc. On the other hand, we
serendipitously discovered a protocluster with a significant concentration of
LBGs and LAEs where no strongly UV ionizing source such as a QSO or radio
galaxy is known to exist. In this cluster field, two populations are spatially
cross-correlated with each other. The relative spatial distribution of LAEs to
LBGs is in stark contrast between the QSO and the cluster fields. We also found
a weak trend showing that the number counts based on Ly-alpha and UV continuum
fluxes of LAEs in the QSO field are slightly lower than in the cluster field,
whereas the number counts of LBGs are almost consistent with each other. The
LAEs avoid the nearby region around the QSO where the local UV background
radiation could be ~100 times stronger than the average for the epoch. The
clustering segregation between LBGs and LAEs seen in the QSO field could be due
to either enhanced early galaxy formation in an overdense environment having
caused all the LAEs to evolve into LBGs, or local photoionization due to the
strong UV radiation from the QSO effectively causing a deficit in low-mass
galaxies like LAEs.


title: Studying Reionization with Ly-alpha Emitters

abstract:
  We show that observations of high-redshift Ly-alpha emitters (LAEs) have the
potential to provide definitive evidence for reionization in the near future.
Using 200 Mpc radiative transfer simulations, we calculate the effect that
patchy reionization has on the line profile, on the luminosity function, and,
most interestingly, on the clustering of emitters for several realistic models
of reionization. Reionization increases the measured clustering of emitters,
and we show that this enhancement would be essentially impossible to attribute
to anything other than reionization. Our results motivate looking for the
signature of reionization in existing LAE data. We find that for stellar
reionization scenarios the angular correlation function of the 58 LAEs in the
Subaru Deep Field z = 6.6 photometric sample is more consistent with a fully
ionized universe (mean volume ionized fraction x_i = 1) than a universe with
x_i < 0.5 at >2-sigma confidence level. Measurements in the next year on Subaru
will increase their z = 6.6 LAE sample by a factor of five and tighten these
limits. If the clustering signature of reionization is detected in a LAE
survey, a comparison with a Lyman-break or a H-alpha survey in the same field
would confirm the reionization hypothesis. We discuss the optimal LAE survey
specifications for detecting reionization, with reference to upcoming programs.


title:
Hydrodynamical simulations of the jet in the symbiotic star MWC 560 III.
  Application to X-ray jets in symbiotic stars

abstract:
  In papers I and II in this series, we presented hydrodynamical simulations of
jet models with parameters representative of the symbiotic system MWC 560.
These were simulations of a pulsed, initially underdense jet in a high density
ambient medium. Since the pulsed emission of the jet creates internal shocks
and since the jet velocity is very high, the jet bow shock and the internal
shocks are heated to high temperatures and should therefore emit X-ray
radiation. In this paper, we investigate in detail the X-ray properties of the
jets in our models. We have focused our study on the total X-ray luminosity and
its temporal variability, the resulting spectra and the spatial distribution of
the emission. Temperature and density maps from our hydrodynamical simulations
with radiative cooling presented in the second paper are used together with
emissivities calculated with the atomic database ATOMDB. The jets in our models
show extended and variable X-ray emission which can be characterized as a sum
of hot and warm components with temperatures that are consistent with
observations of CH Cyg and R Aqr. The X-ray spectra of our model jets show
emission line features which correspond to observed features in the spectra of
CH Cyg. The innermost parts of our pulsed jets show iron line emission in the
6.4 - 6.7 keV range which may explain such emission from the central source in
R Aqr. We conclude that MWC 560 should be detectable with Chandra or
XMM-Newton, and such X-ray observations will provide crucial for understanding
jets in symbiotic stars.


title: Why should anyone care about computing with anyons?

abstract:
  In this article we present a pedagogical introduction of the main ideas and
recent advances in the area of topological quantum computation. We give an
overview of the concept of anyons and their exotic statistics, present various
models that exhibit topological behavior, and we establish their relation to
quantum computation. Possible directions for the physical realization of
topological systems and the detection of anyonic behavior are elaborated.


title: Hydrodynamic Limit for a Particle System with degenerate rates

abstract:
  We study the hydrodynamic limit for some conservative particle systems with
degenerate rates, namely with nearest neighbor exchange rates which vanish for
certain configurations. These models belong to the class of {\sl kinetically
constrained lattice gases} (KCLG) which have been introduced and intensively
studied in physics literature as simple models for the liquid/glass transition.
Due to the degeneracy of rates for KCLG there exists {\sl blocked
configurations} which do not evolve under the dynamics and in general the
hyperplanes of configurations with a fixed number of particles can be
decomposed into different irreducible sets. As a consequence, both the Entropy
and Relative Entropy method cannot be straightforwardly applied to prove the
hydrodynamic limit. In particular, some care should be put when proving the One
and Two block Lemmas which guarantee local convergence to equilibrium. We show
that, for initial profiles smooth enough and bounded away from zero and one,
the macroscopic density profile for our KCLG evolves under the diffusive time
scaling according to the porous medium equation. Then we prove the same result
for more general profiles for a slightly perturbed dynamics obtained by adding
jumps of the Symmetric Simple Exclusion. The role of the latter is to remove
the degeneracy of rates and at the same time they are properly slowed down in
order not to change the macroscopic behavior. The equilibrium fluctuations and
the magnitude of the spectral gap for this perturbed model are also obtained.


title:
Post-Newtonian gravitational radiation and equations of motion via
  direct integration of the relaxed Einstein equations. V. Evidence for the
  strong equivalence principle to second post-Newtonian order

abstract:
  Using post-Newtonian equations of motion for fluid bodies valid to the second
post-Newtonian order, we derive the equations of motion for binary systems with
finite-sized, non-spinning but arbitrarily shaped bodies. In particular we
study the contributions of the internal structure of the bodies (such as
self-gravity) that would diverge if the size of the bodies were to shrink to
zero. Using a set of virial relations accurate to the first post-Newtonian
order that reflect the stationarity of each body, and redefining the masses to
include 1PN and 2PN self-gravity terms, we demonstrate the complete
cancellation of a class of potentially divergent, structure-dependent terms
that scale as s^{-1} and s^{-5/2}, where s is the characteristic size of the
bodies. This is further evidence of the Strong Equivalence Principle, and
supports the use of post-Newtonian approximations to derive equations of motion
for strong-field bodies such as neutron stars and black holes. This extends
earlier work done by Kopeikin.


title:
Proving Regularity of the Minimal Probability of Ruin via a Game of
  Stopping and Control

abstract:
  We reveal an interesting convex duality relationship between two problems:
(a) minimizing the probability of lifetime ruin when the rate of consumption is
stochastic and when the individual can invest in a Black-Scholes financial
market; (b) a controller-and-stopper problem, in which the controller controls
the drift and volatility of a process in order to maximize a running reward
based on that process, and the stopper chooses the time to stop the running
reward and rewards the controller a final amount at that time. Our primary goal
is to show that the minimal probability of ruin, whose stochastic
representation does not have a classical form as does the utility maximization
problem (i.e., the objective's dependence on the initial values of the state
variables is implicit), is the unique classical solution of its
Hamilton-Jacobi-Bellman (HJB) equation, which is a non-linear boundary-value
problem. We establish our goal by exploiting the convex duality relationship
between (a) and (b).


title:
Fermi-liquid and Fermi surface geometry effects in propagation of low
  frequency electromagnetic waves through thin metal films

abstract:
  In the present work we theoretically analyze the contribution from a
transverse Fermi-liquid collective mode to the transmission of electromagnetic
waves through a thin film of a clean metal in the presence of a strong external
magnetic field. We show that at the appropriate Fermi surface geometry the
transverse Fermi-liquid wave may appear in conduction electrons liquid at
frequencies $\omega$ significantly smaller than the cyclotron frequency of
charge carriers $\Omega$ provided that the mean collision frequency $\tau^{-1}$
is smaller than $\omega.$ Also, we show that in realistic metals size
oscillations in the transmission coefficient associated with the Firmi-liquid
mode may be observable in experiments. Under certain conditions these
oscillations may predominate over the remaining size effects in the
transmission coefficient.


title:
Towards experimental entanglement connection with atomic ensembles in
  the single excitation regime

abstract:
  We present a protocol for performing entanglement connection between pairs of
atomic ensembles in the single excitation regime. Two pairs are prepared in an
asynchronous fashion and then connected via a Bell measurement. The resulting
state of the two remaining ensembles is mapped to photonic modes and a reduced
density matrix is then reconstructed. Our observations confirm for the first
time the creation of coherence between atomic systems that never interacted, a
first step towards entanglement connection, a critical requirement for quantum
networking and long distance quantum communications.


title: Chaos and Complexity of quantum motion

abstract:
  The problem of characterizing complexity of quantum dynamics - in particular
of locally interacting chains of quantum particles - will be reviewed and
discussed from several different perspectives: (i) stability of motion against
external perturbations and decoherence, (ii) efficiency of quantum simulation
in terms of classical computation and entanglement production in operator
spaces, (iii) quantum transport, relaxation to equilibrium and quantum mixing,
and (iv) computation of quantum dynamical entropies. Discussions of all these
criteria will be confronted with the established criteria of integrability or
quantum chaos, and sometimes quite surprising conclusions are found. Some
conjectures and interesting open problems in ergodic theory of the quantum many
problem are suggested.


title: Hyperbolicity of Semigroup Algebras

abstract:
  Let $A$ be a finite dimensional $Q-$algebra and $\Gamma subset A$ a
$Z-$order. We classify those $A$ with the property that $Z^2$ does not embed in
$\mathcal{U}(\Gamma)$. We call this last property the hyperbolic property. We
apply this in the case that $A = KS$ a semigroup algebra with $K = Q$ or $K =
Q(\sqrt{-d})$. In particular, when $KS$ is semi-simple and has no nilpotent
elements, we prove that $S$ is an inverse semigroup which is the disjoint union
of Higman groups and at most one cyclic group $C_n$ with $n \in \{5,8,12\}$.


title:
Dust Formation and He II 4686 emission in the Dense Shell of the
  Peculiar Type Ib Supernova 2006jc

abstract:
  We present evidence for the formation of dust grains in an unusual Type Ib SN
based on late-time spectra of SN 2006jc. The progenitor suffered an LBV-like
outburst just 2 yr earlier, and we propose that the dust formation is a
consequence of the SN blast wave overtaking that LBV-like shell. The key
evidence for dust formation is (a) the appearance of a red/near-IR continuum
source fit by 1600 K graphite grains, and (b) fading of the redshifted sides of
He I emission lines, yielding progressively more asymmetric blueshifted lines
as dust obscures receding material. This provides the strongest case yet for
dust formation in any SN Ib/c. Both developments occurred between 51 and 75 d
after peak, while other SNe observed to form dust did so after a few hundred
days. Geometric considerations indicate that dust formed in the dense swept-up
shell between the forward and reverse shocks, and not in the freely expanding
SN ejecta. Rapid cooling leading to dust formation may have been aided by
extremely high shell densities, as indicated by He I line ratios. The brief
epoch of dust formation is accompanied by He II 4686 emission and enhanced
X-ray emission. These clues suggest that the unusual dust formation in this
object was not due to properties of the SN itself, but instead -- like most
peculiarities of SN 2006jc -- was a consequence of the dense environment
created by an LBV-like eruption 2 yr before the SN.


title: Grothendieck rings of basic classical Lie superalgebras

abstract:
  The Grothendieck rings of finite dimensional representations of the basic
classical Lie superalgebras are explicitly described in terms of the
corresponding generalised root systems. We show that they can be interpreted as
the subrings in the weight group rings invariant under the action of certain
groupoids called Weyl groupoids.


title: Boundaries and the Casimir effect in non-commutative space-time

abstract:
  We calculate modifications to the scalar Casimir force between two parallel
plates due to space-time non-commutativity. We devise a heuristic approach to
overcome the difficulties of describing boundaries in non-commutative theories
and predict that boundary corrections are of the same order as non-commutative
volume corrections. Further, both corrections have the form of more
conventional finite surface effects.


title:
Negative differential conductivity in Heisenberg XXZ chain far from
  equilibrium

abstract:
  Negative differential conductivity is reported for the far from equilibrium
quantum spin transport in the insulating regime (J_x < J_z) of finite
Heisenberg XXZ spin 1/2 chains. The phenomenon is reproduced analytically for
small chains of N=4 spins and further analyzed numerically, for up to N=16,
using an efficient pure-state simulation with stochastic spin baths.


title: A survey of debris trails from short-period comets

abstract:
  We observed 34 comets using the 24 micron camera on the Spitzer Space
Telescope. Each image contains the nucleus and covers at least 10^6 km of each
comet's orbit. Debris trails due to mm-sized or larger particles were found
along the orbits of 27 comets; 4 comets had small-particle dust tails and a
viewing geometry that made debris trails impossible to distinguish; and only 3
had no debris trail despite favorable observing conditions. There are now 30
Jupiter-family comets with known debris trails, of which 22 are reported in
this paper for the first time. The detection rate is >80%, indicating that
debris trails are a generic feature of short-period comets. By comparison to
orbital calculations for particles of a range of sizes ejected over 2 yr prior
to observation, we find that particles comprising 4 debris trails are typically
mm-sized while the remainder of the debris trails require particles larger than
this. The lower-limit masses of the debris trails are typically 10^11 g, and
the median mass loss rate is 2 kg/s. The mass-loss rate in trail particles is
comparable to that inferred from OH production rates and larger than that
inferred from visible-light scattering in comae.


title: Representations of Lie algebras arising from polytopes

abstract:
  We present an extremely elementary construction of the simple Lie algebras
over the complex numbers in all of their minuscule representations, using the
vertices of various polytopes. The construction itself requires no complicated
combinatorics and essentially no Lie theory other than the definition of a Lie
algebra; in fact, the Lie algebras themselves appear as by-products of the
construction.


title:
Precise Timing of the X-ray Pulsar 1E 1207.4-5209: A Steady Neutron Star
  Weakly Magnetized at Birth

abstract:
  We analyze all X-ray timing data on 1E 1207.4-5209 in supernova remnant PKS
1209-51/52 gathered in 2000-2005, and find a highly stable rotation with
P=424.130451(4) ms and period derivative of (9.6 +/- 9.4)E-17 s/s. This refutes
previous claims of large timing irregularities in these data. In the dipole
spin-down formalism, the 2-sigma upper limit on period derivative implies an
energy loss rate < 1.5E32 ergs/s, surface magnetic field strength B_p < 3.5E11
G, and characteristic age tau > 24 Myr. This tau exceeds the remnant age by 3
orders of magnitude, requiring that the pulsar was born spinning at its present
period. The X-ray luminosity of 1E 1207.4-5209, L(bol) ~= 2E33 ergs/s at 2 kpc,
exceeds its spin-down energy loss, implying that L(bol) derives from residual
cooling, and perhaps partly from accretion of supernova debris. The upper limit
on B_p is small enough to favor the electron cyclotron model for at least one
of the prominent absorption lines in its soft X-ray spectrum. This is the
second demonstrable case of a pulsar born spinning slowly and with a weak
B-field, after PSR J1852+0040 in Kesteven 79.


title: The Friedel oscillations in the presence of transport currents

abstract:
  We investigate the Friedel oscillations in a nanowire coupled to two
macroscopic electrodes of different potentials. We show that the wave-length of
the density oscillations monotonically increases with the bias voltage, whereas
the amplitude and the spatial decay exponent of the oscillations remain intact.
Using the nonequilibrium Keldysh Green functions, we derive an explicit formula
that describes voltage dependence of the wave-length of the Friedel
oscillations.


title:
Effect of a Zeeman field on the superconductor-ferromagnet transition in
  metallic grains

abstract:
  We investigate the competition between pairing correlations and
ferromagnetism in small metallic grains in the presence of a Zeeman field. Our
analysis is based on the universal Hamiltonian, valid in the limit of large
Thouless conductance. We show that the coexistence regime of superconducting
and ferromagnetic correlations can be made experimentally accessible by tuning
an external Zeeman field. We compare the exact solution of the model with a
mean-field theory and find that the latter cannot describe pairing correlations
in the intermediate regime. We also study the occurrence of spin jumps across
the phase boundary separating the superconducting and coexistence regimes.


title:
On the Hardness of Approximating Stopping and Trapping Sets in LDPC
  Codes

abstract:
  We prove that approximating the size of stopping and trapping sets in Tanner
graphs of linear block codes, and more restrictively, the class of low-density
parity-check (LDPC) codes, is NP-hard. The ramifications of our findings are
that methods used for estimating the height of the error-floor of moderate- and
long-length LDPC codes based on stopping and trapping set enumeration cannot
provide accurate worst-case performance predictions.


title: The Wiretap Channel with Feedback: Encryption over the Channel

abstract:
  In this work, the critical role of noisy feedback in enhancing the secrecy
capacity of the wiretap channel is established. Unlike previous works, where a
noiseless public discussion channel is used for feedback, the feed-forward and
feedback signals share the same noisy channel in the present model. Quite
interestingly, this noisy feedback model is shown to be more advantageous in
the current setting. More specifically, the discrete memoryless modulo-additive
channel with a full-duplex destination node is considered first, and it is
shown that the judicious use of feedback increases the perfect secrecy capacity
to the capacity of the source-destination channel in the absence of the
wiretapper. In the achievability scheme, the feedback signal corresponds to a
private key, known only to the destination. In the half-duplex scheme, a novel
feedback technique that always achieves a positive perfect secrecy rate (even
when the source-wiretapper channel is less noisy than the source-destination
channel) is proposed. These results hinge on the modulo-additive property of
the channel, which is exploited by the destination to perform encryption over
the channel without revealing its key to the source. Finally, this scheme is
extended to the continuous real valued modulo-$\Lambda$ channel where it is
shown that the perfect secrecy capacity with feedback is also equal to the
capacity in the absence of the wiretapper.


title:
Phylogenetic mixtures on a single tree can mimic a tree of another
  topology

abstract:
  Phylogenetic mixtures model the inhomogeneous molecular evolution commonly
observed in data. The performance of phylogenetic reconstruction methods where
the underlying data is generated by a mixture model has stimulated considerable
recent debate. Much of the controversy stems from simulations of mixture model
data on a given tree topology for which reconstruction algorithms output a tree
of a different topology; these findings were held up to show the shortcomings
of particular tree reconstruction methods. In so doing, the underlying
assumption was that mixture model data on one topology can be distinguished
from data evolved on an unmixed tree of another topology given enough data and
the ``correct'' method. Here we show that this assumption can be false. For
biologists our results imply that, for example, the combined data from two
genes whose phylogenetic trees differ only in terms of branch lengths can
perfectly fit a tree of a different topology.


title:
Scaling Behaviors of Graphene Nanoribbon FETs: A Three Dimensional
  Quantum Simulation Study

abstract:
  The scaling behaviors of graphene nanoribbon (GNR) Schottky barrier
field-effect transistors (SBFETs) are studied by solving the non-equilibrium
Green's function (NEGF) transport equation in an atomistic basis set
self-consistently with a three-dimensional Poisson equation. The armchair edge
GNR channel shares similarities with a zigzag CNT, but it has a different
geometry and quantum confinement boundary condition in the transverse
direction. The results indicate that the I-V characteristics are ambipolar and
strongly depend on the GNR width because the bandgap of the GNR is
approximately inversely proportional to its width, which agrees with recent
experiments. A multiple gate geometry improves immunity to short channel
effects, but it offers smaller improvement than it does for Si MOSFETs in terms
of the on-current and transconductance. Reducing the oxide thickness is more
useful for improving transistor performance than using a high-k gate insulator.
Significant increase of the minimal leakage current is observed when the
channel length is scaled below 10nm because the small effective mass
facilitates strong source-drain tunneling. The GNRFET, therefore, does not
promise extending the ultimate scaling limit of Si MOSFETs. The intrinsic
switching speed of a GNR SBFET, however, is several times faster than that of
Si MOSFETs, which could lead to promising high speed electronics applications,
where the large leakage of GNR SBFETs is of less concern.


title:
Irreducible representations and Artin L-functions of quasi-cyclotomic
  fields

abstract:
  We determine all irreducible representations of primary quasi-cyclotomic
fields in this paper. The methods can be applied to determine the irreducible
representations of any quasi-cyclotomic field. We also compute the Artin
L-functions for a class of quasi-cyclotomic fields.


title: Nonlinearity-assisted quantum tunneling in a matter-wave interferometer

abstract:
  We investigate the {\em nonlinearity-assisted quantum tunneling} and
formation of nonlinear collective excitations in a matter-wave interferometer,
which is realised by the adiabatic transformation of a double-well potential
into a single-well harmonic trap. In contrast to the linear quantum tunneling
induced by the crossing (or avoided crossing) of neighbouring energy levels,
the quantum tunneling between different nonlinear eigenstates is assisted by
the nonlinear mean-field interaction. When the barrier between the wells
decreases, the mean-field interaction aids quantum tunneling between the ground
and excited nonlinear eigenstates. The resulting {\em non-adiabatic evolution}
depends on the input states. The tunneling process leads to the generation of
dark solitons, and the number of the generated dark solitons is highly
sensitive to the matter-wave nonlinearity. The results of the numerical
simulations of the matter-wave dynamics are successfully interpreted with a
coupled-mode theory for multiple nonlinear eigenstates.


title: Graphs with chromatic roots in the interval (1,2)

abstract:
  We present an infinite family of 3-connected non-bipartite graphs with
chromatic roots in the interval (1,2) thus resolving a conjecture of Jackson's
in the negative. In addition, we briefly consider other graph classes that are
conjectured to have no chromatic roots in (1,2).


title:
Finite-size correction and bulk hole-excitations for special case of an
  open XXZ chain with nondiagonal boundary terms at roots of unity

abstract:
  Using our solution for the open spin-1/2 XXZ quantum spin chain with N spins
and two arbitrary boundary parameters at roots of unity, the central charge and
the conformal dimensions for bulk hole excitations are derived from the 1/N
correction to the energy (Casimir energy).


title: Dynamical traps and chaotic advection in a meandering jet flow

abstract:
  We continue our study of chaotic mixing and transport of passive particles in
a simple model of a meandering jet flow [Prants, et al, Chaos {\bf 16}, 033117
(2006)]. In the present paper we study and explain phenomenologically a
connection between dynamical, topological, and statistical properties of
chaotic mixing and transport in the model flow in terms of dynamical traps,
singular zones in the phase space where particles may spend arbitrary long but
finite time [Zaslavsky, Phys. D {\bf 168--169}, 292 (2002)]. The transport of
passive particles is described in terms of lengths and durations of zonal
flights which are events between two successive changes of sign of zonal
velocity. Some peculiarities of the respective probability density functions
for short flights are proven to be caused by the so-called rotational-islands
traps connected with the boundaries of resonant islands (including those of the
vortex cores) filled with the particles moving in the same frame. Whereas, the
statistics of long flights can be explained by the influence of the so-called
ballistic-islands traps filled with the particles moving from a frame to frame.


title:
Infrared Optical Properties of Ferropericlase (Mg1-xFexO): Experiment
  and Theory

abstract:
  The temperature dependence of the reflectance spectra of magnesium oxide
(MgO) and ferropericlase (Mg1-xFexO, for x=0.06 and x=0.27) have been measured
over a wide frequency range (~50 to 32000 cm-1) at 295 and 6 K. The complex
dielectric function has been determined from a Kramers-Kronig analysis of the
reflectance. The spectra of the doped materials resembles pure MgO in the
infrared region, but with much broader resonances. We use a shell model to
calculate the dielectric function of ferropericlase, including both anharmonic
phonon-phonon interactions and disorder scattering. These data are relevant to
understanding the heat conductivity of ferropericlase in the earth's lower
mantle.


title: Essential spectra of difference operators on $\sZ^n$-periodic graphs

abstract:
  Let $(\cX, \rho)$ be a discrete metric space. We suppose that the group
$\sZ^n$ acts freely on $X$ and that the number of orbits of $X$ with respect to
this action is finite. Then we call $X$ a $\sZ^n$-periodic discrete metric
space. We examine the Fredholm property and essential spectra of band-dominated
operators on $l^p(X)$ where $X$ is a $\sZ^n$-periodic discrete metric space.
Our approach is based on the theory of band-dominated operators on $\sZ^n$ and
their limit operators.
  In case $X$ is the set of vertices of a combinatorial graph, the graph
structure defines a Schr\"{o}dinger operator on $l^p(X)$ in a natural way. We
illustrate our approach by determining the essential spectra of Schr\"{o}dinger
operators with slowly oscillating potential both on zig-zag and on hexagonal
graphs, the latter being related to nano-structures.


title:
Temporal and diffraction effects in entanglement creation in an optical
  cavity

abstract:
  A practical scheme for entanglement creation between distant atoms located
inside a single-mode optical cavity is discussed. We show that the degree of
entanglement and the time it takes for the entanglement to reach its optimum
value is a sensitive function the initial conditions and the position of the
atoms inside the cavity mode. It is found that the entangled properties of the
two atoms can readily be extracted from dynamics of a simple two-level system.
Effectively, we engineer two coupled qubits whose the dynamics are analogous to
that of a driven single two-level system. It is found that spatial variations
of the coupling constants actually help to create transient entanglement which
may appear on the time scale much longer than that predicted for the case of
equal coupling constants. When the atoms are initially prepared in an entangled
state, they may remain entangled for all times. We also find that the
entanglement exhibits an interesting phenomenon of diffraction when the the
atoms are located between the nodes and antinodes of the cavity mode. The
diffraction pattern of the entanglement varies with time and we explain this
effect in terms of the quantum property of complementarity, which is manifested
as a tradeoff between the knowledge of energy of the exchanged photon versus
the evolution time of the system.


title: The Infrared Cloud Monitor for the MAGNUM Robotic Telescope at Haleakala

abstract:
  We present the most successful infrared cloud monitor for a robotic
telescope. This system was originally developed for the MAGNUM 2-m telescope,
which has been achieving unmanned and automated monitoring observation of
active galactic nuclei at Haleakala on the Hawaiian island of Maui since 2001.
Using a thermal imager and two aspherical mirrors, it at once sees almost the
whole sky at a wavelength of $\lambda\sim 10\mu{\rm m}$. Its outdoor part is
weather-proof and is totally maintenance-free. The images obtained every one or
two minutes are analysed immediately into several ranks of weather condition,
from which our automated observing system not only decides to open or close the
dome, but also selects what types of observations should be done. The whole-sky
data accumulated over four years show that 50$-$60 % of all nights are
photometric, and about 75 % are observable with respect to cloud condition at
Haleakala. Many copies of this system are now used all over the world such as
Mauna Kea in Hawaii, Atacama in Chile, and Okayama and Kiso in Japan.


title: A search for OH 6 GHz maser emission towards southern supernova remnants

abstract:
  OH masers at 1720 MHz have proven to be excellent indicators of interactions
between supernova remnants and molecular clouds. Recent calculations suggest
that the 6049 MHz OH maser line is excited for higher column densities than for
the 1720 MHz line. It is therefore a potentially valuable indicator of
remnant-cloud interaction.
  We present preliminary results of a survey using the Parkes Methanol
Multibeam receiver for 6049 MHz and 6035/6030 MHz OH masers towards 36
supernova remnants and 4 fields in the Large and Small Magellanic Clouds. While
no 6049 MHz masers have been found, three new sites of 6035 and 6030 MHz OH
maser emission have been discovered in star-forming regions.


title:
The Connection between Star-Forming Galaxies, AGN Host Galaxies and
  Early-Type Galaxies in the SDSS

abstract:
  We present a study of the connection between star-forming galaxies, AGN host
galaxies, and normal early-type galaxies in the Sloan Digital Sky Survey
(SDSS). Using the SDSS DR5 and DR4plus data, we select our early-type galaxy
sample in the color versus color-gradient space, and we classify the spectral
types of the selected early-type galaxies into normal, star-forming, Seyfert,
and LINER classes, using several spectral line flux ratios. We investigate the
slope in the fundamental space for each class of early-type galaxies and find
that there are obvious differences in the slopes of the fundamental planes
(FPs) among the different classes of early-type galaxies, in the sense that the
slopes for Seyferts and star-forming galaxies are flatter than those for normal
galaxies and LINERs. This may be the first identification of the systematic
variation of the FP slope among the subclasses of early-type galaxies. The
difference in the FP slope might be caused by the difference in the degree of
nonhomology among different classes or by the difference of gas contents in
their merging progenitors. One possible scenario is that the AGN host galaxies
and star-forming galaxies are formed by gas-rich merging and that they may
evolve into normal early-type galaxies after finishing their star formation or
AGN activities.


title:
Cosmological Symmetry Breaking, Pseudo-scale invariance, Dark Energy and
  the Standard Model

abstract:
  The energy density of the universe today may be dominated by the vacuum
energy of a slowly rolling scalar field. Making a quantum expansion around such
a time dependent solution is found to break fundamental symmetries of quantum
field theory. We call this mechanism cosmological symmetry breaking and argue
that it is different from the standard phenomenon of spontaneous symmetry
breaking. We illustrate this with a toy scalar field theory, whose action
displays a U(1) symmetry. We identify a symmetry, called pseudo-scale
invariance, which sets the cosmological constant exactly equal to zero, both in
classical and quantum theory. This symmetry is also broken cosmologically and
leads to a nonzero vacuum or dark energy. The slow roll condition along with
the observed value of dark energy leads to a value of the background scalar
field of the order of Planck mass. We also consider a U(1) gauge symmetry
model. Cosmological symmetry breaking, in this case, leads to a non zero mass
for the vector field. We also show that a cosmologically broken pseudo-scale
invariance can generate a wide range of masses.


title: Inverse Scattering for Gratings and Wave Guides

abstract:
  We consider the problem of unique identification of dielectric coefficients
for gratings and sound speeds for wave guides from scattering data. We prove
that the "propagating modes" given for all frequencies uniquely determine these
coefficients. The gratings may contain conductors as well as dielectrics and
the boundaries of the conductors are also determined by the propagating modes.


title: Gersten's conjecture

abstract:
  The purpose of this article is to prove that Gersten's conjecture for a
commutative regular local ring is true. As its applications, we will prove the
vanishing conjecture for certain Chow groups, generator conjecture for certain
$K$-groups and Bloch's formula for absolute case.


title: Physics Beyond the Standard Model and Dark Matter

abstract:
  In this lecture note, I discuss why many of us are expecting rich physics at
the TeV scale, drawing analogies from the history of physics in the last
century. Then I review some of the possible candidates of new physics at this
energy scale. I also discuss why we believe much of the matter in the universe
is not atoms (baryons) or compact astronomical objects, and hence requires
physics beyond the standard model. Finally I discuss some of the candidates for
the non-baryonic dark matter.


title: Fermion loop simulation of the lattice Gross-Neveu model

abstract:
  We present a numerical simulation of the Gross-Neveu model on the lattice
using a new representation in terms of fermion loops. In the loop
representation all signs due to Pauli statistics are eliminated completely and
the partition function is a sum over closed loops with only positive weights.
We demonstrate that the new formulation allows to simulate volumes which are
two orders of magnitude larger than those accessible with standard methods.


title:
Inference on Eigenvalues of Wishart Distribution Using Asymptotics with
  respect to the Dispersion of Population Eigenvalues

abstract:
  In this paper we derive some new and practical results on testing and
interval estimation problems for the population eigenvalues of a Wishart matrix
based on the asymptotic theory for block-wise infinite dispersion of the
population eigenvalues. This new type of asymptotic theory has been developed
by the present authors in Takemura and Sheena (2005) and Sheena and Takemura
(2007a,b) and in these papers it was applied to point estimation problem of
population covariance matrix in a decision theoretic framework. In this paper
we apply it to some testing and interval estimation problems. We show that the
approximation based on this type of asymptotics is generally much better than
the traditional large-sample asymptotics for the problems.


title:
On the Prospects for Detection and Identification of Low-Frequency
  Oscillation Modes in Rotating B Type Stars

abstract:
  We study how rotation affects observable amplitudes of high-order g- and
mixed r/g-modes and examine prospects for their detection and identification.
Our formalism, which is described in some detail, relies on a nonadiabatic
generalization of the traditional approximation. Numerical results are
presented for a number of unstable modes in a model of SPB star, at rotation
rates up to 250 km/s. It is shown that rotation has a large effect on mode
visibility in light and in mean radial velocity variations. In most cases, fast
rotation impairs mode detectability of g-modes in light variation, as Townsend
(2003b) has already noted, but it helps detection in radial velocity variation.
The mixed modes, which exist only at sufficiently fast rotation, are also more
easily seen in radial velocity. The amplitude ratios and phase differences are
strongly dependent on the aspect, the rotational velocity and on the mode. The
latter dependence is essential for mode identification.


title:
Full-time dynamics of modulational instability in spinor Bose-Einstein
  condensates

abstract:
  We describe the full-time dynamics of modulational instability in F=1 spinor
Bose-Einstein condensates for the case of the integrable three-component model
associated with the matrix nonlinear Schroedinger equation. We obtain an exact
homoclinic solution of this model by employing the dressing method which we
generalize to the case of the higher-rank projectors. This homoclinic solution
describes the development of modulational instability beyond the linear regime,
and we show that the modulational instability demonstrates the reversal
property when the growth of the modulation amplitude is changed by its
exponential decay.


title: On the width of collective excitations in chiral soliton models

abstract:
  In chiral soliton models for baryons the computation of hadronic decay widths
of baryon resonances is a long standing problem. For the three flavor Skyrme
model I present a solution to this problem that satisfies large--$N_C$
consistency conditions. As an application I focus on the hadronic decay of the
$\Theta$ and $\Theta^*$ pentaquarks.


title: Kekul\'e Cells for Molecular Computation

abstract:
  The configurations of single and double bonds in polycyclic hydrocarbons are
abstracted as Kekul\'e states of graphs. Sending a so-called soliton over an
open channel between ports (external nodes) of the graph changes the Kekul\'e
state and therewith the set of open channels in the graph. This switching
behaviour is proposed as a basis for molecular computation. The proposal is
highly speculative but may have tremendous impact.
  Kekul\'e states with the same boundary behaviour (port assignment) can be
regarded as equivalent. This gives rise to the abstraction of Kekul\'e cells.
The basic theory of Kekul\'e states and Kekul\'e cells is developed here, up to
the classification of Kekul\'e cells with $\leq 4$ ports. To put the theory in
context, we generalize Kekul\'e states to semi-Kekul\'e states, which form the
solutions of a linear system of equations over the field of the bits 0 and 1.
We briefly study so-called omniconjugated graphs, in which every port
assignment of the right signature has a Kekul\'e state. Omniconjugated graphs
may be useful as connectors between computational elements. We finally
investigate some examples with potentially useful switching behaviour.


title: The Einstein relation generalized to non-equilibrium

abstract:
  The Einstein relation connecting the diffusion constant and the mobility is
violated beyond the linear response regime. For a colloidal particle driven
along a periodic potential imposed by laser traps, we test the recent
theoretical generalization of the Einstein relation to the non-equilibrium
regime which involves an integral over measurable velocity correlation
functions.


title:
Boundary Effects in Local Inflation and Spectrum of Density
  Perturbations

abstract:
  We observe that when a local patch in a radiation filled Robertson-Walker
universe inflates by some reason, outside perturbations can enter into the
inflating region. Generally, the physical wavelengths of these perturbations
become larger than the Hubble radius as they cross into the inflating space and
their amplitudes freeze out immediately. It turns out that the corresponding
power spectrum is not scale invariant. Although these perturbations cannot
reach out to a distance inner observer shielded by a de Sitter horizon, they
still indicate a curious boundary effect in local inflationary scenarios.


title:
The 3D soft X-ray cluster-AGN cross-correlation function in the ROSAT
  NEP survey

abstract:
  X-ray surveys facilitate investigations of the environment of AGNs. Deep
Chandra observations revealed that the AGNs source surface density rises near
clusters of galaxies. The natural extension of these works is the measurement
of spatial clustering of AGNs around clusters and the investigation of relative
biasing between active galactic nuclei and galaxies near clusters.The major
aims of this work are to obtain a measurement of the correlation length of AGNs
around clusters and a measure of the averaged clustering properties of a
complete sample of AGNs in dense environments. We present the first measurement
of the soft X-ray cluster-AGN cross-correlation function in redshift space
using the data of the ROSAT-NEP survey. The survey covers 9x9 deg^2 around the
North Ecliptic Pole where 442 X-ray sources were detected and almost completely
spectroscopically identified. We detected a >3sigma significant clustering
signal on scales s<50 h70^-1 Mpc. We performed a classical maximum-likelihood
power-law fit to the data and obtained a correlation length s_0=8.7+1.2-0.3
h_70-1 Mpc and a slope gamma=1.7$^+0.2_-0.7 (1sigma errors). This is a strong
evidence that AGNs are good tracers of the large scale structure of the
Universe. Our data were compared to the results obtained by cross-correlating
X-ray clusters and galaxies. We observe, with a large uncertainty, that the
bias factor of AGN is similar to that of galaxies.


title: ALMA : Fourier phase analysis made possible

abstract:
  Fourier phases contain a vast amount of information about structure in direct
space, that most statistical tools never tap into. We address ALMA's ability to
detect and recover this information, using the probability distribution
function (PDF) of phase increments, and the related concepts of phase entropy
and phase structure quantity. We show that ALMA, with its high dynamical range,
is definitely needed to achieve significant detection of phase structure, and
that it will do so even in the presence of a fair amount of atmospheric phase
noise. We also show that ALMA should be able to recover the actual "amount" of
phase structure in the noise-free case, if multiple configurations are used.


title:
New fluctuation-driven phase transitions and critical phenomena in
  unconventional superconductors

abstract:
  Using the renormalization group method, new type of fluctuation-driven first
order phase transitions and critical phenomena are predicted for certain
classes of ferromagnetic superconductors and superfluids with unconventional
(spin-triplet) Cooper pairing. The problem for the quantum phase transitions at
extremely low and zero temperatures is also discussed. The results can be
applied to a wide class of ferromagnetic superconductive and superfluid
systems, in particular, to itinerant ferromagnets as UGe2 and URhGe.


title: Suppressed star formation in circumnuclear regions in Seyfert galaxies

abstract:
  Feedback from black hole activity is widely believed to play a key role in
regulating star formation and black hole growth. A long-standing issue is the
relation between the star formation and fueling the supermassive black holes in
active galactic nuclei (AGNs). We compile a sample of 57 Seyfert galaxies to
tackle this issue. We estimate the surface densities of gas and star formation
rates in circumnuclear regions (CNRs). Comparing with the well-known
Kennicutt-Schmidt (K-S) law, we find that the star formation rates in CNRs of
most Seyfert galaxies are suppressed in this sample. Feedback is suggested to
explain the suppressed star formation rates.


title:
Brownian excursion area, Wright's constants in graph enumeration, and
  other Brownian areas

abstract:
  This survey is a collection of various results and formulas by different
authors on the areas (integrals) of five related processes, viz.\spacefactor
=1000 Brownian motion, bridge, excursion, meander and double meander; for the
Brownian motion and bridge, which take both positive and negative values, we
consider both the integral of the absolute value and the integral of the
positive (or negative) part. This gives us seven related positive random
variables, for which we study, in particular, formulas for moments and Laplace
transforms; we also give (in many cases) series representations and asymptotics
for density functions and distribution functions. We further study Wright's
constants arising in the asymptotic enumeration of connected graphs; these are
known to be closely connected to the moments of the Brownian excursion area.
The main purpose is to compare the results for these seven Brownian areas by
stating the results in parallel forms; thus emphasizing both the similarities
and the differences. A recurring theme is the Airy function which appears in
slightly different ways in formulas for all seven random variables. We further
want to give explicit relations between the many different similar notations
and definitions that have been used by various authors. There are also some new
results, mainly to fill in gaps left in the literature. Some short proofs are
given, but most proofs are omitted and the reader is instead referred to the
original sources.


title: The Heaviside equation for laser heating of the fullerennes

abstract:
  In his paper the heating of the fullerenes by ultra-short laser pulses is
investigated. The thermal Heaviside equation is formulated and solved for the
Cauchy initial condition The effective thermal relaxation time is calculated..
  Key words: fullerenes, Heaviside thermal equation, effective thermal
relaxation time.


title: Fundamentalist physics: why Dark Energy is bad for Astronomy

abstract:
  Astronomers carry out observations to explore the diverse processes and
objects which populate our Universe. High-energy physicists carry out
experiments to approach the Fundamental Theory underlying space, time and
matter. Dark Energy is a unique link between them, reflecting deep aspects of
the Fundamental Theory, yet apparently accessible only through astronomical
observation. Large sections of the two communities have therefore converged in
support of astronomical projects to constrain Dark Energy. In this essay I
argue that this convergence can be damaging for astronomy. The two communities
have different methodologies and different scientific cultures. By uncritically
adopting the values of an alien system, astronomers risk undermining the
foundations of their own current success and endangering the future vitality of
their field. Dark Energy is undeniably an interesting problem to attack through
astronomical observation, but it is one of many and not necessarily the one
where significant progress is most likely to follow a major investment of
resources.


title:
Double transverse spin asymmetry in the $p^\uparrow\bar{p}^\uparrow$
  Drell-Yan process from Sivers functions

abstract:
  We show that the transverse double spin asymmetry (DSA) in the Drell-Yan
process contributed only from the Sivers functions can be picked out by the
weighting function
$\frac{Q_T}{M^2}(\cos(\phi-\phi_{S_1})\cos(\phi-\phi_{S_2})+3\sin(\phi-\phi_{S_1})\sin(\phi-\phi_{S_2}))$.
The asymmetry is proportional to the product of two Sivers functions from each
hadron $f_{1T}^{\perp(1)}\times f_{1T}^{\perp (1)}$. Using two sets of Sivers
functions extracted from the semi-inclusive deeply elastic scattering data at
HERMES, we estimate this asymmetry in the $p^\uparrow\bar{p}^\uparrow$
Drell-Yan process which is possible to be performed in HESR at GSI. The
prediction of DSA in the Drell-Yan process contributed by the function
$g_{1T}(x,\Vec k_T^2)$, which can be extracted by the weighting function
$\frac{Q_T}{M^2}(3\cos(\phi-\phi_{S_1})\cos(\phi-\phi_{S_2})+\sin(\phi-\phi_{S_1})\sin(\phi-\phi_{S_2}))$,
is also given at GSI.


title: X-ray source counts in the COSMOS field

abstract:
  We present the analysis of the source counts in the XMM-COSMOS survey using
data of the first year of XMM-Newton observations. The survey covers ~2 deg^2
within the region of sky bounded by 9^h57.5^m<R.A.<10^h03.5^m;
1^d27.5^m<DEC<2^d57.5^m with a total net integration time of 504 ks. Using a
maximum likelihood algorithm we detected a total of 1390 sources at least in
one band. Using Monte Carlo simulations to estimate the sky coverage we
produced the logN-logS relations. These relations have been then derived in the
0.5--2 keV, 2--10 keV and 5--10 keV energy bands, down to flux limits of
7.2x10^-16 erg cm^-2 s^-1, 4.0x10^-15 erg cm^-2 s^-1 and 9.7x10^-15 erg cm^-2
s^-1, respectively. These relations have been compared to previous X-ray survey
and to the most recent X-ray background model finding an excellent agreement.
The slightly different normalizations observed in the source counts of COSMOS
and previous surveys can be largely explained as a combination of low counting
statistics and cosmic variance introduced by the large scale structure.


title: Sensitivity of low degree oscillations to the change in solar abundances

abstract:
  Context. The most recent determination of the solar chemical composition,
using a time-dependent, 3D hydrodynamical model of the solar atmosphere,
exhibits a significant decrease of C, N, O abundances compared to their
previous values. Solar models that use these new abundances are not consistent
with helioseismological determinations of the sound speed profile, the surface
helium abundance and the convection zone depth. Aims. We investigate the effect
of changes of solar abundances on low degree p-mode and g-mode characteristics
which are strong constraints of the solar core. We consider particularly the
increase of neon abundance in the new solar mixture in order to reduce the
discrepancy between models using new abundances and helioseismology. Methods.
The observational determinations of solar frequencies from the GOLF instrument
are used to test solar models computed with different chemical compositions. We
consider in particular the normalized small frequency spacings in the low
degree p-mode frequency range. Results. Low-degree small frequency spacings are
very sensitive to changes in the heavy-element abundances, notably neon. We
show that by considering all the seismic constraints, including the small
frequency spacings, a rather large increase of neon abundance by about (0.5 +/-
0.05)dex can be a good solution to the discrepancy between solar models that
use new abundances and low degree helioseismology, subject to adjusting
slightly the solar age and the highest abundances. We also show that the change
in solar abundances, notably neon, considerably affects g-mode frequencies,
with relative frequency differences between the old and the new models higher
than 1.5%


title: Using Image Attributes for Human Identification Protocols

abstract:
  A secure human identification protocol aims at authenticating human users to
a remote server when even the users' inputs are not hidden from an adversary.
Recently, the authors proposed a human identification protocol in the RSA
Conference 2007, which is loosely based on the ability of humans to efficiently
process an image. The advantage being that an automated adversary is not
effective in attacking the protocol without human assistance. This paper
extends that work by trying to solve some of the open problems. First, we
analyze the complexity of defeating the proposed protocols by quantifying the
workload of a human adversary. Secondly, we propose a new construction based on
textual CAPTCHAs (Reverse Turing Tests) in order to make the generation of
automated challenges easier. We also present a brief experiment involving real
human users to find out the number of possible attributes in a given image and
give some guidelines for the selection of challenge questions based on the
results. Finally, we analyze the previously proposed protocol in detail for the
relationship between the secrets. Our results show that we can construct human
identification protocols based on image evaluation with reasonably
``quantified'' security guarantees based on our model.


title:
Extracting the ${\bar q}q$ condensate for light quarks beyond the chiral
  limit in models of QCD

abstract:
  It has recently been suggested \cite{Chang:2006bm} that a reliable and
unambiguous definition of the non-perturbative massive quark condensate could
be provided by considering a non positive-definite class of solutions to the
Schwinger Dyson Equation for the quark propagator. In this paper we show that
this definition is incomplete without considering a third class of solutions.
Indeed, studying these three classes reveals a degeneracy of possible
condensate definitions leading to a whole range of values. However, we show
that the {\it physical} condensate may in fact be extracted by simple fitting
to the Operator Product Expansion, a procedure which is stabilised by
considering the three classes of solution together. We find that for current
quark masses in the range from zero to 25 MeV or so (defined at a scale of 2
GeV in the $\bar{MS}$ scheme), the dynamically generated condensate increases
from the chiral limit in a wide range of phenomenologically successful models
of the confining QCD interaction. Lastly, the role of a fourth class of noded
solutions is briefly discussed.


title: Efficient scheme for one-way quantum computing in thermal cavities

abstract:
  We propose a practical scheme for one-way quantum computing based on
efficient generation of 2D cluster state in thermal cavities. We achieve a
controlled-phase gate that is neither sensitive to cavity decay nor to thermal
field by adding a strong classical field to the two-level atoms. We show that a
2D cluster state can be generated directly by making every two atoms collide in
an array of cavities, with numerically calculated parameters and appropriate
operation sequence that can be easily achieved in practical Cavity QED
experiments. Based on a generated cluster state in Box$^{(4)}$ configuration,
we then implement Grover's search algorithm for four database elements in a
very simple way as an example of one-way quantum computing.


title: Probing Alpha-Vacua of Black Holes in LHC

abstract:
  Motivated by the idea of alpha-vacua in Schwarzschild spacetime, we studied
the deformed spectrum of Hawking radiation. Such a deformation would leave
signatures on the small black hole evaporation in LHC because their vacuum
deviates from the Unruh state.


title: One-dimensional Rydberg Gas in a Magnetoelectric Trap

abstract:
  We study the quantum properties of Rydberg atoms in a magnetic
Ioffe-Pritchard trap which is superimposed by a homogeneous electric field.
Trapped Rydberg atoms can be created in long-lived electronic states exhibiting
a permanent electric dipole moment of several hundred Debye. The resulting
dipole-dipole interaction in conjunction with the radial confinement is
demonstrated to give rise to an effectively one-dimensional ultracold Rydberg
gas with a macroscopic interparticle distance. We derive analytical expressions
for the electric dipole moment and the critical linear density of Rydberg
atoms.


title:
Optical properties of (In,Ga)As capped InAs quantum dots grown on [11k]
  substrates

abstract:
  Using three-dimensional k.p calculation including strain and
piezoelectricity, we showed that the size of the quantum dot (QD) in the growth
direction determines the influence of the (In,Ga)As capping layer on the
optical properties of [11k] grown InAs QDs, where k=1,2,3. For flat dots,
increase of In concentration in the capping layer leads to a decrease of the
transition energy, as is the case of [001] grown QDs, whereas for large dots an
increase of the In concentration in the capping layer is followed by an
increase of the transition energy up to a critical concentration of In, after
which the optical transition energy starts to decrease.


title:
Enhanced sensitivity to time-variation of m_p/m_e in the inversion
  spectrum of ammonia

abstract:
  We calculate the sensitivity of the inversion spectrum of ammonia to possible
time-variation of the ratio of the proton mass to the electron mass,
mu=m_p/m_e. For the inversion transition (lambda= 1.25 cm^{-1}) the relative
frequency shift is significantly enhanced: delta(omega)/omega=-4.46,
delta(mu)/mu. This enhancement allows one to increase sensitivity to the
time-variation of mu using NH_3 spectra for high redshift objects. We use
published data on microwave spectra of the object B0218+357 to place the limit
delta(mu)/mu =(0.6 +/- 1.9) 10^{-6} at redshift z=0.6847; this limit is several
times better than the limits obtained by different methods and may be
significantly improved. Assuming linear time dependence we obtain
dot{mu}/mu=(-1 +/- 3) 10^{-16} yr^{-1}.

categories: astro-ph hep-ph physics.atom-ph physics.space-ph


title: Casimir effect on nontrivial topology spaces in Krein space quantization

abstract:
  Casimir effect of a topologically nontrivial two-dimensional space-time,
through Krein space quantization [1,2], has been calculated. In other words,
auxiliary negative norm states have been utilized here. Presence of negative
norm states play the role of an automatic renormalization device for the
theory. The negative norm states (which do not interact with the physical
world) could be chosen in two perspective. In the first case our method results
in zero or vanishing values for energy. In the second case, however, the result
are the same as the renormalization procedure.


title: Exciton energy transfer in nanotube bundles

abstract:
  Photoluminescence is commonly used to identify the electronic structure of
individual nanotubes. But, nanotubes naturally occur in bundles. Thus, we
investigate photoluminescence of nanotube bundles. We show that their complex
spectra are simply explained by exciton energy transfer between adjacent tubes,
whereby excitation of large gap tubes induces emission from smaller gap ones
via Forster interaction between excitons. The consequent relaxation rate is
faster than non-radiative recombination, leading to enhanced photoluminescence
of acceptor tubes. This fingerprints bundles with different compositions and
opens opportunities to optimize them for opto-electronics.


title: Factorization of the Non-Stationary Schrodinger Operator

abstract:
  We consider a factorization of the non-stationary Schrodinger operator based
on the parabolic Dirac operator introduced by Cerejeiras/ Kahler/ Sommen. Based
on the fundamental solution for the parabolic Dirac operators, we shall
construct appropriated Teodorescu and Cauchy-Bitsadze operators. Afterwards we
will describe how to solve the nonlinear Schrodinger equation using Banach
fixed point theorem.


title:
c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe
  I], and H_2 gas-phase lines

abstract:
  We present a survey of mid-infrared gas-phase lines toward a sample of 76
circumstellar disks around low mass pre-main sequence stars from the Spitzer
"Cores to Disks" legacy program. We report the first detections of [Ne II] and
[Fe I] toward classical T Tauri stars in ~20% respectively ~9% of our sources.
The observed [Ne II] line fluxes and upper limits are consistent with [Ne II]
excitation in an X-ray irradiated disk around stars with X-ray luminosities
L_X=10^{29}-10^{31} erg s^{-1}. [Fe I] is detected at ~10^-5-10^-4 L_Sun, but
no [S I] or [Fe II] is detected down to ~10^{-6} L_Sun. The [Fe I] detections
indicate the presence of gas-rich disks with masses of >~0.1 M_J. No H_2 0-0
S(0) and S(1) disk emission is detected, except for S(1) toward one source.
These data give upper limits on the warm (T~100-200K) gas mass of a few Jovian
masses, consistent with recent T Tauri disk models which include gas heating by
stellar radiation. Compact disk emission of hot (T>~500K) gas is observed
through the H_2 0-0 S(2) and/or S(3) lines toward ~8% of our sources. The line
fluxes are, however, higher by more than an order of magnitude than those
predicted by recent disk models, even when X-ray and excess UV radiation are
included. Similarly the [Ne II]/H_2 0-0 S(2) ratios for these sources are lower
than predicted, consistent with the presence of an additional hot molecular gas
component not included in current disk models. Oblique shocks of stellar winds
interacting with the disk can explain many aspects of the hot gas emission, but
are inconsistent with the non-detection of [S I] and [Fe II] lines.


title:
Probing physical properties of confined fluids within individual
  nanobubbles

abstract:
  Spatially resolved electron energy-loss spectroscopy (EELS) in a scanning
transmission electron microscope (STEM) has been used to investigate as fluidic
phase in nanoubbles embedded in a metallic Pd90Pt10 matrix. Using the 1s->2p
excitation of the He atoms, maps of the He distribution, in particular of its
density an pressure in bubbles of different diameter have been realized, thus
providing an indication of the involved bubble formation mechanism. However,
the short-range Pauli repulsion mechanism between electrons on neighboring
atoms seems insufficient to interpret minute variations of the local local
measurements performed at the interface between the metal and the He bubble.
Simulations relying on the continuum dielectric model have show that these
deviations could be interpreted as an interfzce polarization effect on the He
atomic transition, which should be accounted for when measuring the densities
within the smaller bubbles.


title:
ATLAS Discovery Potential for the Charged Higgs Boson in H+ to tau nu
  Decays

abstract:
  This paper has been withdrawn by the authors in order to comply with the
ATLAS publication policy and is now only available via the CERN cdsweb
(http://cdsweb.cern.ch/record/984015)


title: On dynamical gluon mass generation

abstract:
  The effective gluon propagator constructed with the pinch technique is
governed by a Schwinger-Dyson equation with special structure and gauge
properties, that can be deduced from the correspondence with the background
field method. Most importantly the non-perturbative gluon self-energy is
transverse order-by-order in the dressed loop expansion, and separately for
gluonic and ghost contributions, a property which allows for a meanigfull
truncation. A linearized version of the truncated Schwinger-Dyson equation is
derived, using a vertex that satisfies the required Ward identity and contains
massless poles. The resulting integral equation, subject to a properly
regularized constraint, is solved numerically, and the main features of the
solutions are briefly discussed.


title: Imaging the Ionized Disk of the High-Mass Protostar Orion-I

abstract:
  We have imaged the enigmatic radio source-I (Orion-I) in the Orion-KL nebula
with the VLA at 43 GHz with 34 mas angular resolution. The continuum emission
is highly elongated and is consistent with that expected from a nearly edge-on
disk. The high brightness and lack of strong molecular lines from Orion-I can
be used to argue against emission from dust. Collisional ionization and H-minus
free-free opacity, as in Mira variables, require a central star with >10^5
Lsun, which is greater than infrared observations allow. However, if
significant local heating associated with accretion occurs, lower total
luminosities are possible. Alternatively, photo-ionization from an early B-type
star and p+/e- bremsstrahlung can explain our observations, and Orion-I may be
an example of ionized accretion disk surrounding a forming massive star. Such
accretion disks may not be able to form planets efficiently.


title:
Semiclassical Theory of Bardeen-Cooper-Schrieffer Pairing-Gap
  Fluctuations

abstract:
  Superfluidity and superconductivity are genuine many-body manifestations of
quantum coherence. For finite-size systems the associated pairing gap
fluctuates as a function of size or shape. We provide a parameter free
theoretical description of pairing fluctuations in mesoscopic systems
characterized by order/chaos dynamics. The theory accurately describes
experimental observations of nuclear superfluidity (regular system), predicts
universal fluctuations of superconductivity in small chaotic metallic grains,
and provides a global analysis in ultracold Fermi gases.


title: Coulomb scattering of the Dirac field on de Sitter expanding universe

abstract:
  The lowest order contribution of the amplitude of the Dirac-Coulomb
scattering in de Sitter spacetime is calculated assuming that the initial and
final states of the Dirac field are described by exact solutions of the free
Dirac equation on de Sitter spacetime with a given momentum and helicity. One
studies the difficulties that arises when one passes from the amplitude to
cross section.


title: Low energy proton-proton scattering in effective field theory

abstract:
  Low energy proton-proton scattering is studied in pionless effective field
theory. Employing the dimensional regularization and MS-bar and power
divergence subtraction schemes for loop calculation, we calculate the
scattering amplitude in 1S0 channel up to next-to-next-to leading order and fix
low-energy constants that appear in the amplitude by effective range
parameters. We study regularization scheme and scale dependence in separation
of Coulomb interaction from the scattering length and effective range for the
S-wave proton-proton scattering.


title:
Discontinuous Phase Transition in an Exactly Solvable One-Dimensional
  Creation-Annihilation System

abstract:
  An exactly solvable reaction-diffusion model consisting of first-class
particles in the presence of a single second-class particle is introduced on a
one-dimensional lattice with periodic boundary condition. The number of
first-class particles can be changed due to creation and annihilation
reactions. It is shown that the system undergoes a discontinuous phase
transition in contrast to the case where the density of the second-class
particles is finite and the phase transition is continuous.


title: Axial Resonances in the Open and Hidden Charm Sectors

abstract:
  A SU(4) flavor symmetrical Lagrangian is constructed for the interaction of
the pseudo-scalar mesons with the vector mesons. SU(4) symmetry is broken to
SU(3) by suppression of terms in the Lagrangian where the interaction should be
driven by charmed mesons. Chiral symmetry can be restored by setting this new
SU(4) symmetry breaking parameters to zero. Unitarization in coupled channels
leads to the dynamical generation of resonances. Many known axial resonances
can be identified including the new controversial X(3872) and the structure
found recently by Belle around 3875 MeV in the hidden charm sector. Also new
resonances are predicted, some of them with exotic quantum numbers.


title:
Exact Mapping of the 2+1 Dirac Oscillator onto the Jaynes-Cummings
  Model: Ion-Trap Experimental Proposal

abstract:
  We study the dynamics of the 2+1 Dirac oscillator exactly and find spin
oscillations due to a {\it Zitterbewegung} of purely relativistic origin. We
find an exact mapping of this quantum-relativistic system onto a
Jaynes-Cummings model, describing the interaction of a two-level atom with a
quantized single-mode field. This equivalence allows us to map a series of
quantum optical phenomena onto the relativistic oscillator, and viceversa. We
make a realistic experimental proposal, at reach with current technology, for
studying the equivalence of both models using a single trapped ion.


title:
Correlations and sum rules in a half-space for a quantum two-dimensional
  one-component plasma

abstract:
  This paper is the continuation of a previous one [L. {\v{S}}amaj and B.
Jancovici, 2007 {\it J. Stat. Mech.} P02002]; for a nearly classical quantum
fluid in a half-space bounded by a plain plane hard wall (no image forces), we
had generalized the Wigner-Kirkwood expansion of the equilibrium statistical
quantities in powers of Planck's constant $\hbar$. As a model system for a more
detailed study, we consider the quantum two-dimensional one-component plasma: a
system of charged particles of one species, interacting through the logarithmic
Coulomb potential in two dimensions, in a uniformly charged background of
opposite sign, such that the total charge vanishes. The corresponding classical
system is exactly solvable in a variety of geometries, including the present
one of a half-plane, when $\beta e^2=2$, where $\beta$ is the inverse
temperature and $e$ is the charge of a particle: all the classical $n$-body
densities are known. For the quantum one-component plasma, two sum rules
involving the truncated two-body density (and, for one of them, the density
profile) have been derived, a long time ago, by heuristic macroscopic
arguments: one sum rule is about the asymptotic form along the wall of the
truncated two-body density, the other one is about the dipole moment of the
structure factor. In the two-dimensional case at $\beta e^2=2$, we have now
explicit expressions up to order $\hbar^2$ of these two quantum densities, thus
we can microscopically check the sum rules at this order. The checks are
positive, reinforcing the idea that the sum rules are correct.


title:
Quasi Equilibrium Grid Algorithm: geometric construction for model
  reduction

abstract:
  The Method of Invariant Grid (MIG) is an iterative procedure for model
reduction in chemical kinetics which is based on the notion of Slow Invariant
Manifold (SIM) [1-4]. Important role, in that method, is played by the initial
grid which, once refined, gives a description of the invariant manifold: the
invariant grid. A convenient way to get a first approximation of the SIM is
given by the Spectral Quasi Equilibrium Manifold (SQEM) [1-2]. In the present
paper, a flexible numerical method to construct the discrete analog of a Quasi
Equilibrium Manifold, in any dimension, is presented. That object is named
Quasi Equilibrium Grid (QEG), while the procedure Quasi Equilibrium Grid
Algorithm. Extensions of the QEM notion are also suggested. The QEG is a
numerical tool which can be used to find a grid-based approximation for the
locus of minima of a convex function under some linear constraints. The method
is validated by construction of one and two-dimensional grids for model
hydrogen oxidation reaction.


title:
On a multi-resonant origin of high frequency quasiperiodic oscillations
  in the neutron-star X-ray binary 4U 1636-53

abstract:
  The results we presented were biased because of the typing error in the code
transcription of the equation (A.12). We will replace by the corrected version
soon. The brief of the corrected results can be found at
http://www.physics.cz/research/doc/posters/1181038112_0.pdf


title:
Optical pumping of charged excitons in unintentionally doped InAs
  quantum dots

abstract:
  As an alternative to commonly used electrical methods, we have investigated
the optical pumping of charged exciton complexes addressing impurity related
transitions with photons of the appropriate energy. Under these conditions, we
demonstrate that the pumping fidelity can be very high while still maintaining
a switching behavior between the different excitonic species. This mechanism
has been investigated for single quantum dots of different size present in the
same sample and compared with the direct injection of spectator electrons from
nearby donors.


title: Reduction of boundary effects in spiral MRI experiment PROMISE

abstract:
  Magnetorotational instability (MRI) is one of the most important and most
common instabilities in astrophysics, it is widely accepted that it serves as a
source of turbulent viscosity in accretion disks -- the most energy efficient
objects in the Universe. However it is very difficult to bring this process
down on earth and model it in a laboratory experiment. Several different
approaches have been proposed, one of the most recent is PROMISE
(Potsdam-ROssendorf Magnetorotational InStability Experiment). It consists of a
flow of a liquid metal between two rotating cylinders under applied
current-free spiral magnetic field. The cylinders must be covered with plates
which introduce additional end-effects which alter the flow and make it more
difficult to clearly distinguish between MRI stable and unstable state. In this
paper we propose simple and inexpensive improvement to the PROMISE experiment
which would reduce those undesirable effects.


title: No multi-graviton theories in the presence of a Dirac field

abstract:
  The cross-couplings among several massless spin-two fields (described in the
free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field
are investigated in the framework of the deformation theory based on local BRST
cohomology. Under the hypotheses of locality, smoothness of the interactions in
the coupling constant, Poincare invariance, (background) Lorentz invariance and
the preservation of the number of derivatives on each field, we prove that
there are no consistent cross-interactions among different gravitons in the
presence of a Dirac field. The basic features of the couplings between a single
Pauli-Fierz field and a Dirac field are also emphasized.


title:
Self consistent theory of unipolar charge-carrier injection in
  metal/insulator/metal systems

abstract:
  A consistent device model to describe current-voltage characteristics of
metal/insulator/metal systems is developed. In this model the insulator and the
metal electrodes are described within the same theoretical framework by using
density of states distributions. This approach leads to differential equations
for the electric field which have to be solved in a self consistent manner by
considering the continuity of the electric displacement and the electrochemical
potential in the complete system. The model is capable of describing the
current-voltage characteristics of the metal/insulator/metal system in forward
and reverse bias for arbitrary values of the metal/ insulator injection
barriers. In the case of high injection barriers, approximations are provided
offering a tool for comparison with experiments. Numerical calculations are
performed exemplary using a simplified model of an organic semiconductor.


title: Bandstructure and optical properties of $\alpha-LiIO_{3}$ crystal

abstract:
  The bandstructure was calculated by the full-potential linearized augmented
plane wave method. The result reveals two important insights to the novel
second harmonic generation (SHG) of alpha-phase lithium iodate
($\alpha-LiIO_{3}$) crystal: the existence of finite intra-band momentum matrix
elements due to the non-inversion symmetry of the crystal illuminating the
potential of the intra-band transition, and the strong covalent bonding between
the $I$-atoms and the ligand $O$-atoms resulting the condition of the
double-resonance. An inter-band transition scenario in SHG as $\alpha-LiIO_{3}$
in nano-structure is proposed. The optical properties were calculated within
the theoretical framework of the time-dependent perturbation of the
independent-particle model. The dielectric tensors and the refractive index
were evaluated. Comparisons between the predictions and the results were made:
the x-ray near edge absorption spectra; the refractive index at the static
limit, and at finite frequencies. Possible factors attributing the calculation
errors is discussed.


title: Collective states in social systems with interacting learning agents

abstract:
  We consider a social system of interacting heterogeneous agents with learning
abilities, a model close to Random Field Ising Models, where the random field
corresponds to the idiosyncratic willingness to pay. Given a fixed price,
agents decide repeatedly whether to buy or not a unit of a good, so as to
maximize their expected utilities. We show that the equilibrium reached by the
system depends on the nature of the information agents use to estimate their
expected utilities.


title:
Basic principles of postgrowth annealing of CdTe:Cl ingot to obtain
  semi-insulating crystals

abstract:
  The process of annealing of a CdTe:Cl ingot during its cooling after growth
was studied. The annealing was performed in two stages: a high-temperature
stage, with an approximate equality of chlorine and cadmium vacancy
concentrations established at the thermodynamic equilibrium between the crystal
and vapors of volatile components, and a low-temperature stage, with charged
defects interacting to form neutral associations. The chlorine concentrations
necessary to obtain semi-insulating crystals were determined for various ingot
cooling rates in the high temperature stage. The dependence of the chlorine
concentration [Cl+Te] in the ingot on the temperature of annealing in the
high-temperature stage was found. The carrier lifetimes and drift mobilities
were obtained in relation to the temperature and cadmium vapor pressure in the
postgrowth annealing of the ingot.


title:
On a systematic approach to defects in classical integrable field
  theories

abstract:
  We present an inverse scattering approach to defects in classical integrable
field theories. Integrability is proved systematically by constructing the
generating function of the infinite set of modified integrals of motion. The
contribution of the defect to all orders is explicitely identified in terms of
a defect matrix. The underlying geometric picture is that those defects
correspond to Backlund transformations localized at a given point. A
classification of defect matrices as well as the corresponding defect
conditions is performed. The method is applied to a collection of well-known
integrable models and previous results are recovered (and extended) directly as
special cases. Finally, a brief discussion of the classical $r$-matrix approach
in this context shows the relation to inhomogeneous lattice models and the need
to resort to lattice regularizations of integrable field theories with defects.