title: Weibel Instabilities in a Completely Degenerate Electron Fermi Gas

abstract:
  We study the Weibel instability in a degenerate Fermi plasma. We disclose new
type of quantum Weibel instabilities. In particular, a novel oscillatory Weibel
instability is found and its growth rate is obtained. We reveal a transverse
zero-sound in a quantum degenerate electron gas, which has no counterpart in
the classical consideration.


abstract:
  Let $U_q(A_N)$ be the Drinfeld-Jimbo quantum group of type $A_N$. In this
paper, by using Groebner-Shirshov bases, we give a simple (but not short) proof
of the Rosso-Yamane Theorem on PBW basis of $U_q(A_N)$.


title:
A laser frequency comb that enables radial velocity measurements with a
  precision of 1 cm s$^{-1}$

abstract:
  Searches for extrasolar planets using the periodic Doppler shift of stellar
spectral lines have recently achieved a precision of 60 cm/s (ref 1), which is
sufficient to find a 5-Earth-mass planet in a Mercury-like orbit around a
Sun-like star. To find a 1-Earth-mass planet in an Earthlike orbit, a precision
of 5 cm/s is necessary. The combination of a laser frequency comb with a
Fabry-Perot filtering cavity has been suggested as a promising approach to
achieve such Doppler shift resolution via improved spectrograph wavelength
calibration, with recent encouraging results. Here we report the fabrication of
such a filtered laser comb with up to 40- GHz (1-A) line spacing, generated
from a 1- GHz repetition-rate source, without compromising long-term stability,
reproducibility or spectral resolution. This wide-line-spacing comb, or
`astro-comb', is well matched to the resolving power of high-resolution
astrophysical spectrographs. The astro-comb should allow a precision as high as
1 cm/s in astronomical radial velocity measurements.


title:
Gravitational-radiation losses from the pulsar-white-dwarf binary PSR
  J1141-6545

abstract:
  Pulsars in close binary orbit around another neutron star or a massive white
dwarf make ideal laboratories for testing the predictions of gravitational
radiation and self-gravitational effects. We report new timing measurements of
the pulsar-white-dwarf binary PSR J1141-6545, providing strong evidence that
such asymmetric systems have gravitational wave losses that are consistent with
general relativity. The orbit is found to be decaying at a rate of
$1.04\pm0.06$ times the general relativistic prediction and the Shapiro delay
is consistent with the orbital inclination angle derived from scintillation
measurements. The system provides a unique test-bed for tensor-scalar theories
of gravity; our current measurements place stringent constraints in the theory
space, with a limit of $\alpha_0^2 < 2.1 \times 10^{-5}$ for weakly non-linear
coupling and an asymptotic limit of $\alpha_0^2 < 3.4 \times 10^{-6}$ for
strongly non-linear coupling, where $\alpha_0$ is the linear coupling strength
of matter to an underlying scalar field. This asymptotic limit is nearly three
times smaller than the Cassini bound ($\alpha_0^2 \approx 10^{-5}$).


title: Derandomizing the Isolation Lemma and Lower Bounds for Circuit Size

abstract:
  The isolation lemma of Mulmuley et al \cite{MVV87} is an important tool in
the design of randomized algorithms and has played an important role in several
nontrivial complexity upper bounds. On the other hand, polynomial identity
testing is a well-studied algorithmic problem with efficient randomized
algorithms and the problem of obtaining efficient \emph{deterministic} identity
tests has received a lot of attention recently. The goal of this note is to
compare the isolation lemma with polynomial identity testing: 1. We show that
derandomizing reasonably restricted versions of the isolation lemma implies
circuit size lower bounds. We derive the circuit lower bounds by examining the
connection between the isolation lemma and polynomial identity testing. We give
a randomized polynomial-time identity test for noncommutative circuits of
polynomial degree based on the isolation lemma. Using this result, we show that
derandomizing the isolation lemma implies noncommutative circuit size lower
bounds. The restricted versions of the isolation lemma we consider are natural
and would suffice for the standard applications of the isolation lemma. 2. From
the result of Klivans-Spielman \cite{KS01} we observe that there is a
randomized polynomial-time identity test for commutative circuits of polynomial
degree, also based on a more general isolation lemma for linear forms.
Consequently, derandomization of (a suitable version of) this isolation lemma
also implies circuit size lower bounds in the commutative setting.


title:
Novel insights into charge and spin pairing instabilities in
  nanoclusters

abstract:
  Electron pairing and ferromagnetism in various cluster geometries are studied
with emphasis on tetrahedron and square pyramid under variation of interaction
strength, electron doping and temperature. These exact calculations of charge
and spin collective excitations and pseudogaps yield intriguing insights into
level crossing degeneracies, phase separation and condensation. Criteria for
spin-charge separation and reconciliation driven by interaction strength, next
nearest coupling and temperature are found. Phase diagrams resemble a number of
inhomogeneous, coherent and incoherent nanoscale phases seen recently in high
T$_c$ cuprates, manganites and CMR nanomaterials.


title: Groebner-Shirshov bases for free inverse semigroups

abstract:
  A new construction of a free inverse semigroup was obtained by Poliakova and
Schein in 2005. Based on their result, we find a Groebner-Shirshov basis of a
free inverse semigroup relative to the deg-lex order of words. In particular,
we give the (unique and shortest) Groebner-Shirshov normal forms in the classes
of equivalent words of a free inverse semigroup together with the
Groebner-Shirshov algorithm to transform any word to its normal form.


title: Three-dimensional terminal toric flips

abstract:
  We describe three-dimensional terminal toric flips. We obtain the complete
local description of three-dimensional terminal toric flips.


title:
A log-type moment result for perpetuities and its application to
  martingales in supercritical branching random walks

abstract:
  Infinite sums of i.i.d. random variables discounted by a multiplicative
random walk are called perpetuities and have been studied by many authors. The
present paper provides a log-type moment result for such random variables under
minimal conditions which is then utilized for the study of related moments of
a.s. limits of certain martingales associated with the supercritical branching
random walk. The connection, first observed by the second author in [Iksanov,
A.M. (2004). Elementary fixed points of the BRW smoothing transforms with
infinite number of summands. Stoch. Proc. Appl. 114, 27-50.], arises upon
consideration of a size-biased version of the branching random walk originally
introduced by Lyons in [Lyons, R.(1997). A simple path to Biggins' martingale
convergence for branching random walk. In Athreya, K.B., Jagers, P. (eds.).
Classical and Modern Branching Processes, IMA Volumes in Mathematics and its
Applications, vol. 84, Springer, Berlin, 217-221.]. We also provide a necessary
and sufficient condition for uniform integrability of these martingales in the
most general situation which particularly means that the classical
(LlogL)-condition is not always needed.


title: Scalable quantum computing with atomic ensembles

abstract:
  Atomic ensembles, comprising clouds of atoms addressed by laser fields,
provide an attractive system for both the storage of quantum information, and
the coherent conversion of quantum information between atomic and optical
degrees of freedom. In a landmark paper, Duan et al. (DLCZ) [1] showed that
atomic ensembles could be used as nodes of a quantum repeater network capable
of sharing pairwise quantum entanglement between systems separated by
arbitrarily large distances. In recent years, a number of promising experiments
have demonstrated key aspects of this proposal [2-7]. Here, we describe a
scheme for full scale quantum computing with atomic ensembles. Our scheme uses
similar methods to those already demonstrated experimentally, and yet has
information processing capabilities far beyond those of a quantum repeater.


title: Ward Identities in the Derivation of Hawking Radiation from Anomalies

abstract:
  Robinson and Wilczek suggested a new method of deriving Hawking radiation by
the consideration of anomalies. The basic idea of their approach is that the
flux of Hawking radiation is determined by anomaly cancellation conditions in
the Schwarzschild black hole (BH) background. Iso et al. extended the method to
a charged Reissner-Nordstroem BH and a rotating Kerr BH, and they showed that
the flux of Hawking radiation can also be determined by anomaly cancellation
conditions and regularity conditions of currents at the horizon. Their
formulation gives the correct Hawking flux for all the cases at infinity and
thus provides a new attractive method of understanding Hawking radiation. We
present some arguments clarifying for this derivation. We show that the Ward
identities and boundary conditions for covariant currents without referring to
the Wess-Zumino terms and the effective action are sufficient to derive Hawking
radiation. Our method, which does not use step functions, thus simplifies some
of the technical aspects of the original formulation.


title:
Asymptotic stability of certain sets of associated prime ideals of local
  cohomology modules

abstract:
  Let $(R,\m)$ be a Noetherian local ring $I, J$ two ideals of $R$ and $M$ a
finitely generated $R-$module. It is first shown that for $k\geq -1$ the
integer $r_k = \depth_k(I,J^nM/J^{n+1}M)$, it is the length of a maximal
$(J^nM/J^{n+1}M)-$sequence in dimension $>k$ in $I$ defined by M. Brodmann and
L. T. Nhan \cite{BN}, becomes for large $n$ independent of $n$. Then we prove
in this paper that the sets $\bigcup_{j\le r_k}\Ass_R(H^j_I(J^nM/J^{n+1}M))$
with $k=-1$ or $k=0$, and $\bigcup_{j\le
r_1}\Ass_R(H^j_I(J^nM/J^{n+1}M))\cup\{\m\}$ are stable for large $n$. We also
obtain similar results for modules $M/J^nM$.


title: Gamma-ray Bursts, Classified Physically

abstract:
  From Galactic binary sources, to extragalactic magnetized neutron stars, to
long-duration GRBs without associated supernovae, the types of sources we now
believe capable of producing bursts of gamma-rays continues to grow apace. With
this emergent diversity comes the recognition that the traditional (and newly
formulated) high-energy observables used for identifying sub-classes does not
provide an adequate one-to-one mapping to progenitors. The popular
classification of some > 100 sec duration GRBs as ``short bursts'' is not only
an unpalatable retronym and syntactically oxymoronic but highlights the
difficultly of using what was once a purely phenomenological classification to
encode our understanding of the physics that gives rise to the events. Here we
propose a physically based classification scheme designed to coexist with the
phenomenological system already in place and argue for its utility and
necessity.


title: Continuum theory of memory effect in crack patterns of drying pastes

abstract:
  A possible clarification of memory effect observed in crack patterns of
drying pastes [A. Nakahara and Y. Matsuo, J. Phys. Soc. Japan 74, 1362 (2005)]
is presented in terms of a macroscopic elastoplastic model of isotropic pastes.
We study flows driven by steady gravitational force instead of external
oscillation. The model predicts creation of residual tension in favor of cracks
perpendicular to the flow direction, thus causing the same type of memory
effect as that reported by Nakahara and Matsuo for oscillated CaCO_3 pastes.


title: Paired Orbitals for Different Spins equations

abstract:
  Eigenvalue-type equations for Lowdin-Amos-Hall spin-paired (corresponding)
orbitals are developed to provide an alternative to the standard spin-polarized
Hartree-Fock or Kohn-Sham equations. Obtained equations are non-canonical
unrestricted Hartree-Fock-type equations in which non-canonical orbitals are
fixed to be biorthogonal spin-paired orbitals. To derive paired orbitals for
different spins (PODS) equations there has been applied Adams-Gilbert
localizing operator approach. PODS equations are especially useful for
treatment of the broken-symmetry solutions for antiferromagnetic materials.


title: Inversion doublets of 3N+N cluster structure in excited states of $^4$He

abstract:
  Excited states of $^4$He are studied in four-body calculations with
explicitly correlated Gaussian bases. All the levels below $E_{\rm x}$=26 MeV
are reproduced reasonably well using realistic potentials. An analysis is made
to show how the $0^+_2$ state becomes a resonance but those having almost the
same structure as this state in different spin-isospin channels are not
observed as resonances. The role of tensor force is stressed with a particular
attention to the level spacing between the two $0^-$ states. The calculation of
spectroscopic amplitudes, nucleon decay widths, and spin-dipole transition
strengths demonstrates that the $0^+_2$ state and the three lowest-lying
negative-parity states with $0^-$ and $2^-$ have $^3$H+$p$ and $^3$He+$n$
cluster configurations, leading to the interpretation that these
negative-parity states are the inversion doublet partners of the $0^+_2$ state.


title: Nucleosynthesis in Magnetically Driven Jets from Collapsars

abstract:
  We have made detailed calculations of the composition of magnetically driven
jets ejected from collapsars, or rapidly rotating massive stars, based on
long-term magnetohydrodynamic simulations of their core collapse with various
distributions of magnetic field and angular momentum before collapse. We follow
the evolution of the abundances of about 4000 nuclides from the collapse phase
to the ejection phase and through the jet generation phase using a large
nuclear reaction network. We find that the r-process successfully operates only
in energetic jets (> 1e51 ergs), such that U and Th are synthesized abundantly,
even when the collapsar has a relatively weak magnetic field (1e10 G) and a
moderately rotating core before the collapse. The abundance patterns inside the
jets are similar to those of the r-elements in the solar system. About
0.01-0.06 Msun neutron-rich, heavy nuclei are ejected from a collapsar with
energetic jets. The higher energy jets have larger amounts of Ni56, varying
from 0.00037 to 0.06Msun. Less energetic jets, which eject small amounts of
Ni56, could induce a gamma-ray burst (GRB) a supernova, such as GRB 060505 or
GRB 060614. Considerable amounts of r-elements are likely to be ejected from
GRBs with hypernovae, if both the GRB and hypernova are induced by jets that
are driven near the black hole.


title: Testing data types implementations from algebraic specifications

abstract:
  Algebraic specifications of data types provide a natural basis for testing
data types implementations. In this framework, the conformance relation is
based on the satisfaction of axioms. This makes it possible to formally state
the fundamental concepts of testing: exhaustive test set, testability
hypotheses, oracle. Various criteria for selecting finite test sets have been
proposed. They depend on the form of the axioms, and on the possibilities of
observation of the implementation under test. This last point is related to the
well-known oracle problem. As the main interest of algebraic specifications is
data type abstraction, testing a concrete implementation raises the issue of
the gap between the abstract description and the concrete representation. The
observational semantics of algebraic specifications bring solutions on the
basis of the so-called observable contexts. After a description of testing
methods based on algebraic specifications, the chapter gives a brief
presentation of some tools and case studies, and presents some applications to
other formal methods involving datatypes.


title: Fast rotating condensates in an asymmetric harmonic trap

abstract:
  We investigate the effect of the anisotropy of a harmonic trap on the
behaviour of a fast rotating Bose-Einstein condensate. Fast rotation is reached
when the rotational velocity is close to the smallest trapping frequency,
thereby deconfining the condensate in the corresponding direction. A striking
new feature is the non-existence of visible vortices for the ground state. The
condensate can be described with the lowest Landau level set of states, but
using distorted complex coordinates. We find that the coarse grained atomic
density behaves like an inverted parabola with large radius in the deconfined
direction, and like a fixed Gaussian in the other direction. It has no visible
vortices, but invisible vortices which are needed to recover the mixed
Thomas-Fermi Gaussian profile. There is a regime of small anisotropy and
intermediate rotational velocity where the behaviour is similar to the
isotropic case: a hexagonal Abrikosov lattice of vortices, with an inverted
parabola profile.


title: Groebner-Shirshov Basis for the Chinese Monoid

abstract:
  In this paper, a Groebner-Shirshov basis for the Chinese monoid is obtained
and an algorithm for the normal form of the Chinese monoid is given.


title:
Cosmologies from nonlinear multidimensional gravity with acceleration
  and slowly varying G

abstract:
  We consider multidimensional gravity with a Lagrangian containing the Ricci
tensor squared and the Kretschmann invariant. In a Kaluza-Klein approach with a
single compact extra space of arbitrary dimension, with the aid of a
slow-change approximation (as compared with the Planck scale), we build a class
of spatially flat cosmological models in which both the observed scale factor
$a(\tau)$ and the extra-dimensional one, $b(\tau)$, grow exponentially at large
times, but $b(\tau)$ grows slowly enough to admit variations of the effective
gravitational constant $G$ within observational limits. Such models predict a
drastic change in the physical laws of our Universe in the remote future due to
further growth of the extra dimensions.


title:
Soft-hadronic observables for relativistic heavy-ion collisions at RHIC
  and LHC

abstract:
  The relativistic hydrodynamics together with the single-freeze-out
statistical hadronization model is used to describe the midrapidity hadron
production in ultra-relativistic heavy-ion collisions at RHIC and LHC. At the
highest RHIC energy our approach gives a quite satisfactory global description
of soft hadronic observables including the HBT radii. With the increased
initial energy, from RHIC to LHC, we expect the saturation of the pion elliptic
flow and the moderate increase of the correlation radii.


title:
Interaction of Close-in Planets with the Magnetosphere of their Host
  Stars I: Diffusion, Ohmic Dissipation of Time Dependent Field, Planetary
  Inflation, and Mass Loss

abstract:
  The unanticipated discovery of the first close-in planet around 51 Peg has
rekindled the notion that shortly after their formation outside the snow line,
some planets may have migrated to the proximity of their host stars because of
their tidal interaction with their nascent disks. If these planets indeed
migrated to their present-day location, their survival would require a halting
mechanism in the proximity of their host stars. Most T Tauri stars have strong
magnetic fields which can clear out a cavity in the innermost regions of their
circumstellar disks and impose magnetic induction on the nearby young planets.
Here we consider the possibility that a magnetic coupling between young stars
and planets could quench the planet's orbital evolution. After a brief
discussion of the complexity of the full problem, we focus our discussion on
evaluating the permeation and ohmic dissipation of the time dependent component
of the stellar magnetic field in the planet's interior. Adopting a model first
introduced by C. G. Campbell for interacting binary stars, we determine the
modulation of the planetary response to the tilted magnetic field of a
non-synchronously spinning star. We first compute the conductivity in the young
planets, which indicates that the stellar field can penetrate well into the
planet's envelope in a synodic period. For various orbital configurations, we
show that the energy dissipation rate inside the planet is sufficient to induce
short-period planets to inflate. This process results in mass loss via Roche
lobe overflow and in the halting of the planet's orbital migration.


title:
Analysis of nucleus-nucleus collisions at high energies and Random
  Matrix Theory

abstract:
  We propose a novel statistical approach to the analysis of experimental data
obtained in nucleus-nucleus collisions at high energies which borrows from
methods developed within the context of Random Matrix Theory. It is applied to
the detection of correlations in momentum distributions of emitted particles.
We find good agreement between the results obtained in this way and a standard
analysis based on the method of effective mass spectra and two-pair correlation
function often used in high energy physics. The method introduced here is free
from unwanted background contributions.


title:
From Network Structure to Dynamics and Back Again: Relating dynamical
  stability and connection topology in biological complex systems

abstract:
  The recent discovery of universal principles underlying many complex networks
occurring across a wide range of length scales in the biological world has
spurred physicists in trying to understand such features using techniques from
statistical physics and non-linear dynamics. In this paper, we look at a few
examples of biological networks to see how similar questions can come up in
very different contexts. We review some of our recent work that looks at how
network structure (e.g., its connection topology) can dictate the nature of its
dynamics, and conversely, how dynamical considerations constrain the network
structure. We also see how networks occurring in nature can evolve to modular
configurations as a result of simultaneously trying to satisfy multiple
structural and dynamical constraints. The resulting optimal networks possess
hubs and have heterogeneous degree distribution similar to those seen in
biological systems.


title: Normality in group rings

abstract:
  Let $KG$ be the group ring of a group $G$ over a commutative ring $K$ with
unity. The rings $KG$ are described for which $xx^\sigma=x^\sigma x$ for all
$x=\sum_{g\in G}\alpha_gg\in KG$, where \quad $x\mapsto x^\sigma=~\sum_{g\in
G}\alpha_gf(g)\sigma(g)$\quad is an involution of $KG$; here $f: G\to U(K)$ is
a homomorphism and $\sigma$ is an anti-automorphism of order two of $G$.


title: Precision tests with a new class of dedicated ether-drift experiments

abstract:
  In principle, by accepting the idea of a non-zero vacuum energy, the physical
vacuum of present particle physics might represent a preferred reference frame.
By treating this quantum vacuum as a relativistic medium, the non-zero
energy-momentum flow expected in a moving frame should effectively behave as a
small thermal gradient and could, in principle, induce a measurable anisotropy
of the speed of light in a loosely bound system as a gas. We explore the
phenomenological implications of this scenario by considering a new class of
dedicated ether-drift experiments where arbitrary gaseous media fill the
resonating optical cavities. Our predictions cover most experimental set up and
should motivate precise experimental tests of these fundamental issues.


title:
Large MIMO Detection: A Low-Complexity Detector at High Spectral
  Efficiencies

abstract:
  We consider large MIMO systems, where by `{\em large}' we mean number of
transmit and receive antennas of the order of tens to hundreds. Such large MIMO
systems will be of immense interest because of the very high spectral
efficiencies possible in such systems. We present a low-complexity detector
which achieves uncoded near-exponential diversity performance for hundreds of
antennas (i.e., achieves near SISO AWGN performance in a large MIMO fading
environment) with an average per-bit complexity of just $O(N_tN_r)$, where
$N_t$ and $N_r$ denote the number of transmit and receive antennas,
respectively. With an outer turbo code, the proposed detector achieves good
coded bit error performance as well. For example, in a 600 transmit and 600
receive antennas V-BLAST system with a high spectral efficiency of 200 bps/Hz
(using BPSK and rate-1/3 turbo code), our simulation results show that the
proposed detector performs close to within about 4.6 dB from theoretical
capacity. We also adopt the proposed detector for the low-complexity decoding
of high-rate non-orthogonal space-time block codes (STBC) from division
algebras (DA). For example, we have decoded the $16\times 16$ full-rate
non-orthogonal STBC from DA using the proposed detector and show that it
performs close to within about 5.5 dB of the capacity using 4-QAM and rate-3/4
turbo code at a spectral efficiency of 24 bps/Hz. The practical feasibility of
the proposed high-performance low-complexity detector could potentially trigger
wide interest in the implementation of large MIMO systems. In large MC-CDMA
systems with hundreds of users, the proposed detector is shown to achieve near
single-user performance at an average per-bit complexity linear in number of
users, which is quite appealing for its use in practical CDMA systems.


title:
Investigation of Space-Time Structure of the Discharge with an
  Electrolytic Anode and Face-Type, Air Half-Space Directed Cathode (Gatchina's
  Discharge)

abstract:
  Despite of its limited capabilities for ball-lightning modeling, the
chemically active dust plasma of electric discharges is a very interesting
physical object. Gatchina's discharge, which gives a possibility to study the
dust-gas fireball, represents a complex non-stationary process, combining the
creation and the destruction of relatively long-living high-enthalpy
microscopic states with non-ideal dust plasma and with a gas-dynamic form,
resulting in appearance of a spherical luminous object. In the present work we
studied spatial structure of the discharge and its dynamics with the help of
electric and optical measurements.


title: Geometric effects of noise on Cooper pair pumping

abstract:
  Several works investigated the connection between Cooper pair pumping and the
geometric and topological properties of the pumping cycle in the parameters
space. Recently the predicted connection between Berry's phase and pumped
charge was observed experimentally. In the present work we analyze the effects
of noise on Cooper pair pumping. We show that dissipation induces a new
geometric contribution in the transferred charge and we propose an experiment
where the theory can be probed.


title: A Polytropic Model of Quark Stars

abstract:
  A polytropic quark star model is suggested in order to establish a general
framework in which theoretical quark star models could be tested by
observations. The key difference between polytropic quark stars and the
polytropic model studied previously for normal (i.e., non-quarkian) stars is
related to two issues: (i) a constant term representing the contribution of
vacuum energy may be added in the energy density and the pressure for a quark
star, but not for a normal star; (ii) the quark star models with non-vanishing
density at the stellar surface are not avoidable due to the strong interaction
between quarks. The first one implies that the vacuum inside a quark star is
different from that outside, while the second one is relevant to the effect of
color confinement. The polytropic equations of state are stiffer than that
derived in conventional realistic models (e.g., the bag model) for quark
matter, and pulsar-like stars calculated with a polytropic equation of state
could then have high maximum masses (> 2 M_sun). Quark stars can also be very
low massive, and be still gravitationally stable even if the polytropic index,
n, is greater than 3. All these would result in different mass-radius
relations, which could be tested by observations. In addition, substantial
strain energy would develop in a solid quark star during its accretion/spindown
phase, and could be high enough to take a star-quake. The energy released
during star-quakes could be as high as ~ 10^{47} ergs if the tangential
pressure is ~ 10^{-6} higher than the radial one.


title: Electronic Structure in Gapped Graphene with Coulomb Potential

abstract:
  In this paper, we numerically study the bound electron states induced by long
range Coulomb impurity in gapped graphene and the quasi-bound states in
supercritical region based on the lattice model. We present a detailed
comparison between our numerical simulations and the prediction of the
continuum model which is described by the Dirac equation in (2+1)-dimensional
Quantum Electrodynamics (QED). We also use the Fano's formalism to investigate
the quasi-bound state development and design an accessible experiments to test
the decay of the supercritical vacuum in the gapped graphene.


title:
Energy equilibriation processes of electrons, magnons and phonons on the
  femtosecond timescale

abstract:
  By means of time-resolved Kerr spectroscopy experiments we relate the energy
dissipation processes on the femtosecond (electron-spin relaxation time
$\tau_{el-sp}$) and nanosecond timescale (Gilbert relaxation $\tau_{\alpha}$)
and compare the results to the first microscopic model, which was proposed by
Koopmans. For both energy dissipation processes, Elliot-Yafet scattering is
proposed as the dominant contributor. We controllably manipulate the energy
dissipation processes by transition metal doping (Pd) and rare earth doping
(Dy) of a Permalloy film and find that while a change of $\tau_{\alpha}$ of
more than a factor two is observed, \tau_{el-sp}$ remains constant, contrary to
the predictions of the model. We explain the discrepancies by relaxation
channels not considered in the original microscopic model and identify thereby
the applicability of the model and possible necessary extensions to the model.


title: Cauchy's Arm Lemma on a Growing Sphere

abstract:
  We propose a variant of Cauchy's Lemma, proving that when a convex chain on
one sphere is redrawn (with the same lengths and angles) on a larger sphere,
the distance between its endpoints increases. The main focus of this work is a
comparison of three alternate proofs, to show the links between Toponogov's
Comparison Theorem, Legendre's Theorem and Cauchy's Arm Lemma.


title: Objective priors for the bivariate normal model

abstract:
  Study of the bivariate normal distribution raises the full range of issues
involving objective Bayesian inference, including the different types of
objective priors (e.g., Jeffreys, invariant, reference, matching), the
different modes of inference (e.g., Bayesian, frequentist, fiducial) and the
criteria involved in deciding on optimal objective priors (e.g., ease of
computation, frequentist performance, marginalization paradoxes). Summary
recommendations as to optimal objective priors are made for a variety of
inferences involving the bivariate normal distribution. In the course of the
investigation, a variety of surprising results were found, including the
availability of objective priors that yield exact frequentist inferences for
many functions of the bivariate normal parameters, including the correlation
coefficient.


title: On the 2D Cahn-Hilliard equation with inertial term

abstract:
  P. Galenko et al. proposed a modified Cahn-Hilliard equation to model rapid
spinodal decomposition in non-equilibrium phase separation processes. This
equation contains an inertial term which causes the loss of any regularizing
effect on the solutions. Here we consider an initial and boundary value problem
for this equation in a two-dimensional bounded domain. We prove a number of
results related to well-posedness and large time behavior of solutions. In
particular, we analyze the existence of bounded absorbing sets in two different
phase spaces and, correspondingly, we establish the existence of the global
attractor. We also demonstrate the existence of an exponential attractor.


title: A geometric Newton method for Oja's vector field

abstract:
  Newton's method for solving the matrix equation $F(X)\equiv AX-XX^TAX=0$ runs
up against the fact that its zeros are not isolated. This is due to a symmetry
of $F$ by the action of the orthogonal group. We show how
differential-geometric techniques can be exploited to remove this symmetry and
obtain a ``geometric'' Newton algorithm that finds the zeros of $F$. The
geometric Newton method does not suffer from the degeneracy issue that stands
in the way of the original Newton method.


title:
First-Principles Study of Correlation Effects in VO2: Peierls vs.
  Mott-Hubbard

abstract:
  We present a study of VO2 in the rutile and monoclinic (M1) phases by means
of all-electron full-potential LMTO GW calculation. Full frequency dependence
and the off-diagonal matrix elements of the self-energy are taken into account.
As a result of dynamical correlation, a satellite structure is found above the
$t_{2g}$ quasiparticle peak but not below, in both the rutile and monoclinic
phases. For the monoclinic structure, the insulating state is not obtained
within the usual 1-shot GW calculation. We perform a simplified
"self-consistent" GW scheme by adding a uniform shift to the conduction band
levels and recalculating the quasiparticle wavefunctions accordingly. An
insulating solution with a gap of approximately 0.6 eV is obtained, in
agreement with experiments.


title: Quadratic distances on probabilities: A unified foundation

abstract:
  This work builds a unified framework for the study of quadratic form distance
measures as they are used in assessing the goodness of fit of models. Many
important procedures have this structure, but the theory for these methods is
dispersed and incomplete. Central to the statistical analysis of these
distances is the spectral decomposition of the kernel that generates the
distance. We show how this determines the limiting distribution of natural
goodness-of-fit tests. Additionally, we develop a new notion, the spectral
degrees of freedom of the test, based on this decomposition. The degrees of
freedom are easy to compute and estimate, and can be used as a guide in the
construction of useful procedures in this class.


title: Methods for linear optical quantum Fredkin gate

abstract:
  We consider the realization of quantum Fredkin gate with only linear optics
and single photons. First we construct a heralded Fredkin gate using four
heralded controlled-not (CNOT) gates. Then we simplify this method to a
post-selected one utilizing only two CNOT gates. We also give a possible
realization of this method which is feasible with current experimental
technology. Another post-selected scheme requires time entanglement of the
input photons but needs no ancillary photons.


title: Static quark-antiquark pairs at finite temperature

abstract:
  In a framework that makes close contact with modern effective field theories
for non-relativistic bound states at zero temperature, we study the real-time
evolution of a static quark-antiquark pair in a medium of gluons and light
quarks at finite temperature. For temperatures ranging from values larger to
smaller than the inverse distance of the quark and antiquark, 1/r, and at short
distances, we derive the potential between the two static sources, and
calculate their energy and thermal decay width. Two mechanisms contribute to
the thermal decay width: the imaginary part of the gluon self energy induced by
the Landau damping phenomenon, and the quark-antiquark color singlet to color
octet thermal break up. Parametrically, the first mechanism dominates for
temperatures such that the Debye mass is larger than the binding energy, while
the latter, which we quantify here for the first time, dominates for
temperatures such that the Debye mass is smaller than the binding energy. If
the Debye mass is of the same order as 1/r, our results are in agreement with a
recent calculation of the static Wilson loop at finite temperature. For
temperatures smaller than 1/r, we find new contributions to the potential, both
real and imaginary, which may be relevant to understand the onset of heavy
quarkonium dissociation in a thermal medium.


title: On Debye temperature anomaly observed in Ge-Se-Ag glasses

abstract:
  Anomalous Values of Debye temperature have been obtained from Lamb Mossbauer
factor measurements of Ge-Se-Ag glasses. We show that this anomaly may arise
due to the presence of anharmonic potential at the high spin ferrous site. In
this paper, we use q Lamb Mossbauer factor and anharmonic Lamb Mossbauer factor
to study this anharmoncity.


title:
Combinatorial Hopf algebras, noncommutative Hall-Littlewood functions,
  and permutation tableaux

abstract:
  We introduce a new family of noncommutative analogues of the Hall-Littlewood
symmetric functions. Our construction relies upon Tevlin's bases and simple
q-deformations of the classical combinatorial Hopf algebras. We connect our new
Hall-Littlewood functions to permutation tableaux, and also give an exact
formula for the q-enumeration of permutation tableaux of a fixed shape. This
gives an explicit formula for: the steady state probability of each state in
the partially asymmetric exclusion process (PASEP); the polynomial enumerating
permutations with a fixed set of weak excedances according to crossings; the
polynomial enumerating permutations with a fixed set of descent bottoms
according to occurrences of the generalized pattern 2-31.


title: Woven Graph Codes: Asymptotic Performances and Examples

abstract:
  Constructions of woven graph codes based on constituent block and
convolutional codes are studied. It is shown that within the random ensemble of
such codes based on $s$-partite, $s$-uniform hypergraphs, where $s$ depends
only on the code rate, there exist codes satisfying the Varshamov-Gilbert (VG)
and the Costello lower bound on the minimum distance and the free distance,
respectively. A connection between regular bipartite graphs and tailbiting
codes is shown. Some examples of woven graph codes are presented. Among them an
example of a rate $R_{\rm wg}=1/3$ woven graph code with $d_{\rm free}=32$
based on Heawood's bipartite graph and containing $n=7$ constituent rate
$R^{c}=2/3$ convolutional codes with overall constraint lengths $\nu^{c}=5$ is
given. An encoding procedure for woven graph codes with complexity proportional
to the number of constituent codes and their overall constraint length
$\nu^{c}$ is presented.


title: Large Deviations Principle for Stochastic Scalar Conservation Laws

abstract:
  We investigate large deviations for a family of conservative stochastic PDEs
(conservation laws) in the asymptotic of jointly vanishing noise and viscosity.
We obtain a first large deviations principle in a space of Young measures. The
associated rate functional vanishes on a wide set, the so-called set of
measure-valued solutions to the limiting conservation law. We therefore
investigate a second order large deviations principle, thus providing a
quantitative characterization of non-entropic solutions to the conservation
law.


title:
Intrinsic Electric Dipole Moments of Paramagnetic Atoms: Rubidium and
  Cesium

abstract:
  The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the
intrinsic EDM contribution from that of its constituent electrons and a
scalar--pseudo-scalar (S-PS) electron-nucleus interactions. The electron EDM
and the S-PS EDM contribution to atomic EDM scales as Z^3. Thus, the heavy
paramagnetic atomic systems will exhibit large enhancement factors. However,
the nature of the coupling is so small that it becomes an interest of high
precision atomic experiments. In this work, we have computed the EDM
enhancement factors of the ground states of Rb and Cs due to both the electron
EDM and the S-PS EDM using the relativistic coupled-cluster (RCC) theory. The
importance of obtaining the precise enhancement factors and the experimental
results in deducing a reliable limit on the electron EDM is emphasized.


title: Magnetoresistance of antidot lattices with grain boundaries

abstract:
  The magnetotransport properties of antidot lattices containing artificially
designed grain boundaries have been measured. We find that the grain boundaries
broaden the commensurability resonances and displace them anisotropically.
These phenomena are unexpectedly weak but differ characteristically from
isotropic, Gaussian disorder in the antidot positions. The observations are
interpreted in terms of semiclassical trajectories which tend to localize along
the grain boundaries within certain magnetic field intervals. Furthermore, our
results indicate how the transport through superlattices generated by
self-organizing templates may get influenced by grain boundaries.


title:
On the parabolic-elliptic limit of the doubly parabolic Keller--Segel
  system modelling chemotaxis

abstract:
  We establish new convergence results, in strong topologies, for solutions of
the parabolic-parabolic Keller--Segel system in the plane, to the corresponding
solutions of the parabolic-elliptic model, as a physical parameter goes to
zero. Our main tools are suitable space-time estimates, implying the global
existence of slowly decaying (in general, nonintegrable) solutions for these
models, under a natural smallness assumption.


title:
Quotient correlation: A sample based alternative to Pearson's
  correlation

abstract:
  The quotient correlation is defined here as an alternative to Pearson's
correlation that is more intuitive and flexible in cases where the tail
behavior of data is important. It measures nonlinear dependence where the
regular correlation coefficient is generally not applicable. One of its most
useful features is a test statistic that has high power when testing nonlinear
dependence in cases where the Fisher's $Z$-transformation test may fail to
reach a right conclusion. Unlike most asymptotic test statistics, which are
either normal or $\chi^2$, this test statistic has a limiting gamma
distribution (henceforth, the gamma test statistic). More than the common
usages of correlation, the quotient correlation can easily and intuitively be
adjusted to values at tails. This adjustment generates two new concepts--the
tail quotient correlation and the tail independence test statistics, which are
also gamma statistics. Due to the fact that there is no analogue of the
correlation coefficient in extreme value theory, and there does not exist an
efficient tail independence test statistic, these two new concepts may open up
a new field of study. In addition, an alternative to Spearman's rank
correlation, a rank based quotient correlation, is also defined. The advantages
of using these new concepts are illustrated with simulated data and a real data
analysis of internet traffic.


title: Numerical studies of planar closed random walks

abstract:
  Lattice numerical simulations for planar closed random walks and their
winding sectors are presented. The frontiers of the random walks and of their
winding sectors have a Hausdorff dimension $d_H=4/3$. However, when properly
defined by taking into account the inner 0-winding sectors, the frontiers of
the random walks have a Hausdorff dimension $d_H\approx 1.77$.


title: Searching for Hyper-Velocity Stars

abstract:
  We present our survey for subluminous hyper-velocity candidates, which has
been successfully initiated at the ESO NTT and the Calar Alto 3.5 m telescope.


title: Cosmic-ray acceleration in supernova shocks

abstract:
  Galactic cosmic rays are widely believed to be accelerated in expanding shock
waves initiated by supernova explosions. The theory of diffusive shock
acceleration of cosmic rays is now well established, but two fundamental
questions remain partly unanswered: what is the acceleration efficiency, i.e.
the fraction of the total supernova energy converted to cosmic-ray energy, and
what is the maximum kinetic energy achieved by particles accelerated in
supernova explosions? Recent observations of supernova remnants, in X-rays with
the Chandra and XMM-Newton satellites and in very-high-energy gamma rays with
several ground-based atmospheric Cerenkov telescopes, have provided new pieces
of information concerning these two questions. After a review of these
observations and their current interpretations, I show that complementary
information on the diffusive shock acceleration process can be obtained by
studying the radio emission from extragalactic supernovae. As an illustration,
a nonlinear model of diffusive shock acceleration is applied to the radio light
curves of the supernova SN 1993J, which exploded in the nearby galaxy M81. The
results of the model suggest that most of the Galactic cosmic rays may be
accelerated during the early phase of interaction between the supernova ejecta
and the wind lost from the progenitor star.


title: Neutrino magnetic moment signatures in the supernova neutrino signal

abstract:
  It is known that if neutrino is a Dirac fermion with magnetic moment, then
\nu_L -> \nu_R -> \nu_L transition of supernova neutrinos may occur. The first
stage of such transition is due to the neutrino spin flip inside the hot dense
supernova core, while the second one - due to the neutrino spin precession in
the galactic magnetic field on the way from the supernova to terrestrial
detectors. This can result in the detection of 60-200 MeV neutrinos
simultaneously with the "normal" supernova neutrino signal, which would be a
smoking gun for the Dirac neutrino magnetic moment, \mu. We argue that in case
of a nearby supernova explosion (~10 kpc away from the Earth) one may observe
such high-energy events in Super-Kamiokande if \mu \gtrsim 10^{-13} \mu_B, and
in a Mt-scale detector if \mu \gtrsim 0.5*10^{-13} \mu_B. Such an observation
by itself, however, may be not sufficient to determine the value of the
magnetic moment, because of the ignorance of the interstellar magnetic field.
We point out that if in addition a deficit of the neutronization burst
neutrinos is established, it would be possible to extract the value of the
magnetic moment from observations. We also briefly discuss a possible Majorana
magnetic moment signature due to \nu_e -> \bar{\nu}_{\mu,\tau} flip inside the
supernova core.


title: Towards Asteroseismology of PG1605+072

abstract:
  We present our attempt to characterise the frequency spectrum of the bright V
361 Hya star PG1605$+$072 from atmospheric parameter and radial velocity
variations through a spectroscopic approach. Therefore we used time resolved
spectroscopy ($\approx$9000 spectra) to detect line profile variations from
which variations of the effective temperature and gravity, together with their
phases, are extracted by means of a quantitative spectral analysis. The
theoretical modelling of adequate pulsation modes with the \textit{BRUCE} and
\textit{KYLE} codes allows to derive constraints on the mode's degree and order
from the observed frequencies.


title: A $\chi^2$ veto for continuous gravitational wave searches

abstract:
  $\chi^2$ vetoes are commonly used in searching for gravitational waves, in
particular for broad-band signals, but they can also be applied to narrow-band
continuous wave signals, such as those expected from rapidly rotating neutron
stars. In this paper we present a $\chi^2$ veto adapted to the Hough transform
searches for continuous gravitational wave signals; we characterize the
$\chi^2$-significance plane for different frequency bands; and discuss the
expected performance of this veto in LIGO analysis.


title: Fundamental groups and Diophantine geometry

abstract:
  We give a brief exposition on the uses of non-commutative fundamental groups
for the study of Diophantine problems via a non-abelian Albanese map.


title: Multiplicity for critical and overcritical equations

abstract:
  On a Riemannian compact manifold, we give existence and multiplicity results
for solutions of elliptic PDE by introducing isometry invariances. When the
groups we used have finite orbits, we get multiplicity results for equations
with the classical critical Sobolev exponent, for instance the Yamabe equation.
When there is no finite orbits, the multiplicity is obtained for equations with
overcritical exponents.


title:
Stray-light restoration of full-disk CaII K solar observations: a case
  study

abstract:
  AIMS: We investigate whether restoration techniques, such as those developed
for application to current observations, can be used to remove stray-light
degradation effects on archive CaII K full-disk observations. We analyze to
what extent these techniques can recover homogeneous time series of data.
METHODS:We develop a restoration algorithm based on a method presented by
Walton & Preminger (1999). We apply this algorithm to data for both present-day
and archive CaII K full-disk observations, which were acquired using the PSPT
mounted at the Rome Observatory, or obtained by digitization of Mt Wilson
photographic-archive spectroheliograms. RESULTS:We show that the restoring
algorithm improves both spatial resolution and photometric contrast of the
analyzed solar observations. We find that the improvement in spatial resolution
is similar for analyzed recent and archive data. On the other hand, the
improvement of photometric contrast is quite poor for the archive data, with
respect to the one obtained for the present-day images. We show that the
quality of restored archive data depends on the photographic calibration
applied to the original observations. In particular, photometry can be
recovered with a restoring algorithm if the photographic-calibration preserves
the intensity information stored in the original data, principally outside the
solar-disk observations.


title:
Fulde-Ferrell-Larkin-Ovchinnikov State in the absence of a Magnetic
  Field

abstract:
  We propose that in a system with pocket Fermi surfaces, a pairing state with
a finite total momentum q_tot like the Fulde-Ferrell-Larkin-Ovchinnikov state
can be stabilized even without a magnetic field. When a pair is composed of
electrons on a pocket Fermi surface whose center is not located at Gamma point,
the pair inevitably has finite q_tot. To investigate this possibility, we
consider a two-orbital model on a square lattice that can realize pocket Fermi
surfaces and we apply fluctuation exchange approximation. Then, by changing the
electron number n per site, we indeed find that such superconducting states
with finite q_tot are stabilized when the system has pocket Fermi surfaces.


title:
Controllability of networks of one-dimensional second order p.d.e. - An
  algebraic approach

abstract:
  We discuss controllability of systems that are initially given by boundary
coupled p.d.e. of second order. Those systems may be described by modules over
a certain subring R of the ring of Mikusinski operators with compact support.
We show that the ring R is a Bezout domain. This property is utilized in order
to derive algebraic and trajectory related controllability results.


title: The Warped Disc of NGC 4258

abstract:
  We consider the properties of the warped accretion disc in NGC 4258 which is
delineated by maser emission. We use our analytical models to consider whether
the disc could be warped by Lense-Thirring precession. We show that such models
fit the shape of the disc well and we determine the goodness of fit for various
combinations of the warp radius and the disc and black hole configurations.
Though the fits are compelling evidence, we note that such a model has
implications for the formation and longevity of the disc which might be
problematic for the current understanding of Seyfert Galaxies.


title: Bound-state Effects on Top Quark Production at Hadron Colliders

abstract:
  We study bound-state effects on the t\bar{t} production cross section in the
threshold region at hadron colliders. The bound-state effects are important
particularly at the LHC where the gluon fusion is the dominant subprocess. Due
to the formation of t\bar{t} resonances in the J=0 color-singlet channel of gg
\to t\bar{t} and the large width of the top quark, the t\bar{t} invariant-mass
distribution peaks at a few GeV below the t\bar{t} threshold, and it is
significantly enhanced over the naive NLO prediction until several GeV above
the threshold. We present predictions of the t\bar{t} invariant-mass
distribution which incorporate both the bound-state effects and initial-state
radiations up to NLO. The bound-state effects would lead to a substantial
deformation of top-quark kinematical distributions in the threshold region.


title:
Noncommutative Gorenstein Projective Schemes and Gorenstein-Injective
  Sheaves

abstract:
  We prove that if a positively-graded ring $R$ is Gorenstein and the
associated torsion functor has finite cohomological dimension, then the
corresponding noncommutative projective scheme ${\rm Tails}(R)$ is a Gorenstein
category in the sense of \cite{EEG}. Moreover, under this condition, a (right)
recollement relating Gorenstein-injective sheaves in ${\rm Tails}(R)$ and
(graded) Gorenstein-injective $R$-modules is given.


title:
Experimental determination of a nonclassical Glauber-Sudarshan P
  function

abstract:
  A quantum state is nonclassical if its Glauber-Sudarshan P function fails to
be interpreted as a probability density. This quantity is often highly
singular, so that its reconstruction is a demanding task. Here we present the
experimental determination of a well-behaved P function showing negativities
for a single-photon-added thermal state. This is a direct visualization of the
original definition of nonclassicality. The method can be useful under
conditions for which many other signatures of nonclassicality would not
persist.


title:
Evolution of low-frequency features in the CMB spectrum due to
  stimulated Compton scattering and Doppler-broadening

abstract:
  We discuss a new solution of the Kompaneets-equation for physical situations
in which low frequency photons, forming relatively narrow spectral details, are
Compton scattered in an isotropic, infinite medium with an intense ambient
blackbody field that is very close to full thermodynamic equilibrium with the
free electrons. In this situation the background-induced stimulated Compton
scattering slows down the motion of photons toward higher frequencies by a
factor of 3 in comparison with the solution that only takes into account
Doppler-broadening and boosting. This new solution is important for detailed
computations of cosmic microwave background spectral distortions arising due to
uncompensated atomic transitions of hydrogen and helium in the early Universe.
In addition we derive another analytic solution that only includes the
background-induced stimulated Compton scattering and is valid for power-law
ambient radiation fields. This solution might have interesting applications for
radio lines arising inside of bright extra-galactic radio source, where
according to our estimates line shifts because of background-induced stimulated
scattering could be amplified and even exceed the line broadening due to the
Doppler-effect.


title:
The focusing energy-critical nonlinear Schr\"odinger equation in
  dimensions five and higher

abstract:
  We consider the focusing energy-critical nonlinear Schr\"odinger equation
$iu_t+\Delta u = - |u|^{\frac4{d-2}}u$ in dimensions $d\geq 5$. We prove that
if a maximal-lifespan solution $u:I\times\R^d\to \C$ obeys $\sup_{t\in
I}\|\nabla u(t)\|_2<\|\nabla W\|_2$, then it is global and scatters both
forward and backward in time. Here $W$ denotes the ground state, which is a
stationary solution of the equation. In particular, if a solution has both
energy and kinetic energy less than those of the ground state $W$ at some point
in time, then the solution is global and scatters. We also show that any
solution that blows up with bounded kinetic energy must concentrate at least
the kinetic energy of the ground state. Similar results were obtained by Kenig
and Merle in \cite{Evian, kenig-merle} for spherically symmetric initial data
and dimensions $d=3,4,5$.


title: Chiral fermions in a spacetime with multiple warping

abstract:
  In a six dimensional brane world model with multiple $S_1/Z_2$ warping, two
of the 4-branes at the boundaries have coordinate dependent brane tensions in
order to implement the orbifolded boundary conditions consistently. Such brane
tension is shown to be equivalent to a scalar field distribution on the brane
[1]. We show that in such a scenario a masslesss left chiral fermion on the
4-brane localizes naturally on the standard model 3-brane located at one edge
of the compact manifold while the massless right chiral fermion wave function
as well as the wave functions for the massive fermion modes peak away from this
brane. This offers a mechanism of obtaining massless chiral fermion with only
one of its chiral component present in our brane.


title:
Impact-driven effects in thin-film growth: steering and transient
  mobility at the Ag(110) surface

abstract:
  Low-energy atomic impacts on the Ag(110) surface are investigated by
molecular dynamics simulations based on reliable many-body semiempirical
potentials. Trajectory deflections (steering) caused by the atom-surface
interaction are observed, together with impact-following, transient-mobility
effects. Such processes are quantitatively analysed and their dependence on the
initial kinetic energy and on the impinging direction is discussed. A clear
influence of the surface anisotropy on both steering and transient mobility
effects is revealed by our simulations for the simple isolated-atom case and in
the submonolayer-growth regime. For the latter case, we illustrate how steering
and transient mobility affect the film morphology at the nanoscale.


title: Differentiation of Kaltofen's division-free determinant algorithm

abstract:
  Kaltofen has proposed a new approach in [Kaltofen 1992] for computing matrix
determinants. The algorithm is based on a baby steps/giant steps construction
of Krylov subspaces, and computes the determinant as the constant term of a
characteristic polynomial. For matrices over an abstract field and by the
results of Baur and Strassen 1983, the determinant algorithm, actually a
straight-line program, leads to an algorithm with the same complexity for
computing the adjoint of a matrix [Kaltofen 1992]. However, the latter is
obtained by the reverse mode of automatic differentiation and somehow is not
``explicit''. We study this adjoint algorithm, show how it can be implemented
(without resorting to an automatic transformation), and demonstrate its use on
polynomial matrices.


title:
Observation of Geometric Phases for Three-Level Systems using NMR
  Interferometry

abstract:
  Geometric phase (GP) independent of energy and time rely only on the geometry
of state space. It has been argued to have potential fault tolerance and plays
an important role in quantum information and quantum computation. We present
the first experiment for producing and measuring an Abelian geometric phase
shift in a three-level system by using NMR interferometry. In contrast to
existing experiments, based on the geometry of $S^2$, our experiment concerns
the geometric phase with the geometry of $SU(3)/U(2)$. Two interacting qubits
have been used to provide such a three-dimensional Hilbert space.


title: Submanifolds with ample normal bundles and a conjecture of Hartshorne

abstract:
  The Hartshorne conjecture predicts that two submanifolds X and Y in a
projective manifold Z with ample normal bundles meets as soon as dim X + dim Y
is at least dim Z. We mostly assume slightly stronger that one of the normal
bundles is positive in the sense of Griffiths. We observe that the conjecture
holds generically, relate it to question on cones of cycles and verify it in
various cases.


title: A Sobolev-like inequality for the Dirac operator

abstract:
  In this article, we prove a Sobolev-like inequality for the Dirac operator on
closed compact Riemannian spin manifolds with a nearly optimal Sobolev
constant. As an application, we give a criterion for the existence of solutions
to a nonlinear equation with critical Sobolev exponent involving the Dirac
operator. We finally specify a case where this equation can be solved.


title:
Metal-insulator transition in the two-dimensional fully polarized
  homogeneous electron gas from Hartree-Fock solutions

abstract:
  We determine the ground state of the two-dimensional, fully polarized
electron gas within the Hartree-Fock approximation without imposing any
particular symmetries on the solutions. At low electronic densities, the Wigner
crystal solution is stable, but for higher densities ($r_s$ less than $\sim 3$)
we obtain a ground state of different symmetry: the charge density forms a
triangular lattice with about 11% more sites than electrons. We argue that this
conducting state with broken translational symmetry remains the ground state of
the high density region in the thermodynamic limit giving rise to a metal to
insulator transition.


title: Testing for Homogeneity with Kernel Fisher Discriminant Analysis

abstract:
  We propose to investigate test statistics for testing homogeneity in
reproducing kernel Hilbert spaces. Asymptotic null distributions under null
hypothesis are derived, and consistency against fixed and local alternatives is
assessed. Finally, experimental evidence of the performance of the proposed
approach on both artificial data and a speaker verification task is provided.


title: Pruning a L\'evy continuum random tree

abstract:
  Given a general critical or sub-critical branching mechanism, we define a
pruning procedure of the associated L\'evy continuum random tree. This pruning
procedure is defined by adding some marks on the tree, using L\'evy snake
techniques. We then prove that the resulting sub-tree after pruning is still a
L\'evy continuum random tree. This last result is proved using the exploration
process that codes the CRT, a special Markov property and martingale problems
for exploration processes. We finally give the joint law under the excursion
measure of the lengths of the excursions of the initial exploration process and
the pruned one.


title: Narayana numbers and Schur-Szego composition

abstract:
  In the present paper we find a new interpretation of Narayana polynomials
N_n(x) which are the generating polynomials for the Narayana numbers N_{n,k}
counting Dyck paths of length n and with exactly k peaks. Strangely enough
Narayana polynomials also occur as limits as n->oo of the sequences of
eigenpolynomials of the Schur-Szego composition map sending (n-1)-tuples of
polynomials of the form (x+1)^{n-1}(x+a) to their Schur-Szego product, see
below. As a corollary we obtain that every N_n(x) has all roots real and
non-positive. Additionally, we present an explicit formula for the density and
the distribution function of the asymptotic root-counting measure of the
polynomial sequence {N_n(x)}.


title: Complete integration of the aligned Newman Tamburino Maxwell solutions

abstract:
  We investigate the cylindrical class of Newman Tamburino equations in the
presence of an aligned Maxwell field. After obtaining a complete integration of
the field equations we look at the possible vacuum limits and we examine the
symmetries of the general solution.


title: A New Estimator for the Number of Species in a Population

abstract:
  We consider the classic problem of estimating T, the total number of species
in a population, from repeated counts in a simple random sample. We look first
at the Chao-Lee estimator: we initially show that such estimator can be
obtained by reconciling two estimators of the unobserved probability, and then
develop a sequence of improvements culminating in a Dirichlet prior Bayesian
reinterpretation of the estimation problem. By means of this, we obtain
simultaneous estimates of T, of the normalized interspecies variance $\gamma^2$
and of the parameter $\lambda$ of the prior. Several simulations show that our
estimation method is more flexible than several known methods we used as
comparison; the only limitation, apparently shared by all other methods, seems
to be that it cannot deal with the rare cases in which $\gamma^2 >1$

categories: stat.AP math.PR math.ST q-bio.QM stat.TH


title: VLBI Surveys of Active Galactic Nuclei

abstract:
  A review is given on the current status and selected results from large VLBI
surveys of compact extragalactic radio sources made between 13 cm and 3 mm
wavelengths and covering the entire sky. More than 4200 objects are observed
and imaged with dynamic ranges from a hundred to several thousand at
(sub)parsec scales. Implications to the VSOP-2 project are discussed.


title: The compound Poisson distribution and return times in dynamical systems

abstract:
  Previously it has been shown that some classes of mixing dynamical systems
have limiting return times distributions that are almost everywhere Poissonian.
Here we study the behaviour of return times at periodic points and show that
the limiting distribution is a compound Poissonian distribution. We also derive
error terms for the convergence to the limiting distribution. We also prove a
very general theorem that can be used to establish compound Poisson
distributions in many other settings.


title:
A Semi-Automatic Framework to Discover Epistemic Modalities in
  Scientific Articles

abstract:
  Documents in scientific newspapers are often marked by attitudes and opinions
of the author and/or other persons, who contribute with objective and
subjective statements and arguments as well. In this respect, the attitude is
often accomplished by a linguistic modality. As in languages like english,
french and german, the modality is expressed by special verbs like can, must,
may, etc. and the subjunctive mood, an occurrence of modalities often induces
that these verbs take over the role of modality. This is not correct as it is
proven that modality is the instrument of the whole sentence where both the
adverbs, modal particles, punctuation marks, and the intonation of a sentence
contribute. Often, a combination of all these instruments are necessary to
express a modality. In this work, we concern with the finding of modal verbs in
scientific texts as a pre-step towards the discovery of the attitude of an
author. Whereas the input will be an arbitrary text, the output consists of
zones representing modalities.


title:
Exact solution of a model DNA-inversion genetic switch with
  orientational control

abstract:
  DNA inversion is an important mechanism by which bacteria and bacteriophage
switch reversibly between phenotypic states. In such switches, the orientation
of a short DNA element is flipped by a site-specific recombinase enzyme. We
propose a simple model for a DNA inversion switch in which recombinase
production is dependent on the switch state (orientational control). Our model
is inspired by the fim switch in Escherichia coli. We present an exact
analytical solution of the chemical master equation for the model switch, as
well as stochastic simulations. Orientational control causes the switch to
deviate from Poissonian behaviour: the distribution of times in the on state
shows a peak and successive flip times are correlated.


title:
Vortex core states in superfluid Fermi-Fermi mixtures with unequal
  masses

abstract:
  We analyze the vortex core states of two-species (mass imbalanced) superfluid
fermion mixtures as a function of two-body binding energy in two dimensions. In
particular we solve the Bogoliubov-de Gennes equations for a population
balanced mixture of $^{6}$Li and $^{40}$K atoms at zero temperature. We find
that the vortex core is mostly occupied by the light-mass ($^{6}$Li) fermions
and that the core density of the heavy-mass ($^{40}$K) fermions is highly
depleted. This is in contrast with the one-species (mass balanced) mixtures
with balanced populations where an equal amount of density depletion is found
at the vortex core for both pseudospin components.


title:
Triple Michelson Interferometer for a Third-Generation Gravitational
  Wave Detector

abstract:
  The upcoming European design study `Einstein gravitational-wave Telescope'
represents the first step towards a substantial, international effort for the
design of a third-generation interferometric gravitational wave detector. It is
generally believed that third-generation instruments might not be installed
into existing infrastructures but will provoke a new search for optimal
detector sites. Consequently, the detector design could be subject to fewer
constraints than the on-going design of the second generation instruments. In
particular, it will be prudent to investigate alternatives to the traditional
L-shaped Michelson interferometer. In this article, we review an old proposal
to use three Michelson interferometers in a triangular configuration. We use
this example of a triple Michelson interferometer to clarify the terminology
and will put this idea into the context of more recent research on
interferometer technologies. Furthermore the benefits of a triangular detector
will be used to motivate this design as a good starting point for a more
detailed research effort towards a third-generation gravitational wave
detector.


title:
Density of electron states in a rectangular lattice under uniaxial
  stress

abstract:
  The closed analytical expression for the electron density of states function
in a rectangular lattice is derived in an elementary way in terms of complete
elliptic integrals of the first kind. The lattice can be treated as a deformed
square lattice under uniform uniaxial stress (or strain). In contrast to
hydrostatic case the uniaxial pressure, say along axis y, modifies a length of
the y-bonds while the x-bonds remain intact. It also alters the corresponding
tight-binding transfer integral gamma_2 between two y-nearest-neighbours
leaving unchanged the gamma_1 for x-nn interactions. Due to stress-induced
lowering symmetry of this simple model one can get an insight into the
decoupling of its density of states on dependence of the lattice deformation or
transfer integrals anisotropy.


title: Estimation of Ambiguity Functions With Limited Spread

abstract:
  This paper proposes a new estimation procedure for the ambiguity function of
a non-stationary time series. The stochastic properties of the empirical
ambiguity function calculated from a single sample in time are derived.
Different thresholding procedures are introduced for the estimation of the
ambiguity function. Such estimation methods are suitable if the ambiguity
function is only non-negligible in a limited region of the ambiguity plane. The
thresholds of the procedures are formally derived for each point in the plane,
and methods for the estimation of nuisance parameters that the thresholds
depend on are proposed. The estimation method is tested on several signals, and
reductions in mean square error when estimating the ambiguity function by
factors of over a hundred are obtained. An estimator of the spread of the
ambiguity function is proposed.


title:
Multivariate Feller conditions in term structure models: Why do(n't) we
  care?

abstract:
  In this paper, the relevance of the Feller conditions in discrete time
macro-finance term structure models is investigated. The Feller conditions are
usually imposed on a continuous time multivariate square root process to ensure
that the roots have nonnegative arguments. For a discrete time approximate
model, the Feller conditions do not give this guarantee. Moreover, in a
macro-finance context the restrictions imposed might be economically
unappealing. At the same time, it has also been observed that even without the
Feller conditions imposed, for a practically relevant term structure model,
negative arguments rarely occur. Using models estimated on German data, we
compare the yields implied by (approximate) analytic exponentially affine
expressions to those obtained through Monte Carlo simulations of very high
numbers of sample paths. It turns out that the differences are rarely
statistically significant, whether the Feller conditions are imposed or not.
Moreover, economically the differences are negligible, as they are always below
one basis point.

categories: q-fin.ST math.PR math.ST q-fin.CP stat.TH


title: On the Spectral Properties of Matrices Associated with Trend Filters

abstract:
  This paper is concerned with the spectral properties of matrices associated
with linear filters for the estimation of the underlying trend of a time
series. The interest lies in the fact that the eigenvectors can be interpreted
as the latent components of any time series that the filter smooths through the
corresponding eigenvalues. A difficulty arises because matrices associated with
trend filters are finite approximations of Toeplitz operators and therefore
very little is known about their eigenstructure, which also depends on the
boundary conditions or, equivalently, on the filters for trend estimation at
the end of the sample. Assuming reflecting boundary conditions, we derive a
time series decomposition in terms of periodic latent components and
corresponding smoothing eigenvalues. This decomposition depends on the local
polynomial regression estimator chosen for the interior. Otherwise, the
eigenvalue distribution is derived with an approximation measured by the size
of the perturbation that different boundary conditions apport to the
eigenvalues of matrices belonging to algebras with known spectral properties,
such as the Circulant or the Cosine. The analytical form of the eigenvectors is
then derived with an approximation that involves the extremes only. A further
topic investigated in the paper concerns a strategy for a filter design in the
time domain. Based on cut-off eigenvalues, new estimators are derived, that are
less variable and almost equally biased as the original estimator, based on all
the eigenvalues. Empirical examples illustrate the effectiveness of the method.


title: On the Stretch Factor of Convex Delaunay Graphs

abstract:
  Let C be a compact and convex set in the plane that contains the origin in
its interior, and let S be a finite set of points in the plane. The Delaunay
graph DG_C(S) of S is defined to be the dual of the Voronoi diagram of S with
respect to the convex distance function defined by C. We prove that DG_C(S) is
a t-spanner for S, for some constant t that depends only on the shape of the
set C. Thus, for any two points p and q in S, the graph DG_C(S) contains a path
between p and q whose Euclidean length is at most t times the Euclidean
distance between p and q.


title: Secondary invariants for Frechet algebras and quasihomomorphisms

abstract:
  A Frechet algebra endowed with a multiplicatively convex topology has two
types of invariants: homotopy invariants (topological K-theory and periodic
cyclic homology) and secondary invariants (multiplicative K-theory and the
non-periodic versions of cyclic homology). The aim of this paper is to
establish a Riemann-Roch-Grothendieck theorem relating direct images for
homotopy and secondary invariants of Frechet m-algebras under finitely summable
quasihomomorphisms.


title:
Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II
  Using Photon Timing

abstract:
  We present the results of the first hadron collider search for heavy,
long-lived neutralinos that decay via lightest neutralino to gamma gravitino in
gauge-mediated supersymmetry breaking models. Using an integrated luminosity of
$570\pm34 pb^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV, we select
$\gamma$+jet+missing transverse energy candidate events based on the arrival
time of a high-energy photon at the electromagnetic calorimeter as measured
with a timing system that was recently installed on the CDF II detector. We
find 2 events, consistent with the background estimate of 1.3$\pm$0.7 events.
While our search strategy does not rely on model-specific dynamics, we set
cross section limits and place the world-best 95% C.L. lower limit on the
neutralino mass of 101 GeV at lifetime = 5 ns.


title: On a question of Koll\'ar

abstract:
  We show: If a bounded domain in a Stein space covers a compact complex space,
it must be smooth. This give a negative answer to a question of Koll\'ar.
Furthermore, we deduce some related results.


title:
Effects of the cosmological expansion on the bubble nucleation rate for
  relativistic first-order phase transitions

abstract:
  I calculate the first corrections to the dynamical pre-exponential factor of
the bubble nucleation rate for a relativistic first-order phase transition in
an expanding cosmological background by estimating the effects of the Hubble
expansion rate on the critical bubbles of Langer's statistical theory of
metastability. I also comment on possible applications and problems that arise
when one considers the field theoretical extensions of these results (the
Coleman-De Luccia and Hawking-Moss instantons and decay rates).


title: Discrete schemes for Gaussian curvature and their convergence

abstract:
  In this paper, several discrete schemes for Gaussian curvature are surveyed.
The convergence property of a modified discrete scheme for the Gaussian
curvature is considered. Furthermore, a new discrete scheme for Gaussian
curvature is resented. We prove that the new scheme converges at the regular
vertex with valence not less than 5. By constructing a counterexample, we also
show that it is impossible for building a discrete scheme for Gaussian
curvature which converges over the regular vertex with valence 4. Finally,
asymptotic errors of several discrete scheme for Gaussian curvature are
compared.


title:
Bound States, Yangian Symmetry and Classical r-matrix for the AdS5 x S5
  Superstring

abstract:
  We show that the recently found S-matrices describing the scattering of
two-particle bound states of the light-cone string sigma model on AdS5 x S5 are
compatible with Yangian symmetry. In case the invariance with respect to the
centrally extended su(2|2) algebra is not sufficient to fully specify the
scattering matrix, the requirement of Yangian symmetry provides an alternative
to the Yang-Baxter equation and leads to a complete, up to an overall phase,
determination of the S-matrix. We then compare the semi-classical limit of the
bound state S-matrices with the universal classical r-matrix by Beisert and
Spill evaluated in the corresponding bound state representations and find
perfect agreement.


title: Quasihomomorphisms and the residue Chern character

abstract:
  We develop a general procedure, based on the renormalized eta-cochain, which
allows to find local representatives of the bivariant Chern character of
finitely summable quasihomomorphisms. In particular, using zeta-function
renormalization we obtain a bivariant generalization of the Connes-Moscovici
residue formula, and explain the link with chiral and multiplicative anomalies
in quantum field theory.


title:
XMM-Newton observations of the supernova remnant IC 443: II. evidence of
  stellar ejecta in the inner regions

abstract:
  We investigate the spatial distribution of the physical and chemical
properties of the hot X-ray emitting plasma of the supernova remnant IC 443, in
order to get important constraints on its ionization stage, on the progenitor
supernova explosion, on the age of the remnant, and its physical association
with a close pulsar wind nebula.
  The hard X-ray thermal emission (1.4-5.0 keV) of IC 443 displays a
centrally-peaked morphology, its brightness peaks being associated with hot
(kT>1 keV) X-ray emitting plasma. A ring-shaped structure, characterized by
high values of equivalent widths and median photon energy, encloses the PWN.
Its hard X-ray emission is spectrally characterized by a collisional ionization
equilibrium model, and strong emission lines of Mg, Si, and S, requiring
oversolar metal abundances. Dynamically, the location of the ejecta ring
suggests an SNR age of ~4,000 yr.
  The presence of overionized plasma in the inner regions of IC 443, addressed
in previous works, is much less evident in our observations.


title: Ferromagnetic Josephson junction with precessing magnetization

abstract:
  The Josephson current in a diffusive
superconductor/ferromagnet/superconductor junction with precessing
magnetization is calculated within the quasiclassical theory of
superconductivity. When the junction is phase-biased, a stationary current
(without a.c. component) can flow through it despite the non-equilibrium
condition. A large critical current is predicted due to a dynamically induced
long range triplet proximity effect. Such effect could be observed in a
conventional hybrid device close to the ferromagnetic resonance.


title:
BCS BEC crossover and phase structure of relativistic system: a
  variational approach

abstract:
  We investigate here the BCS BEC crossover in relativistic systems using a
variational construct for the ground state and the minimization of the
thermodynamic potential. This is first studied in a four fermion point
interaction model and with a BCS type ansatz for the ground state with fermion
pairs. It is shown that the antiparticle degrees of freedom play an important
role in the BCS BEC crossover physics, even when the ratio of fermi momentum to
the mass of the fermion is small. We also consider the phase structure for the
case of fermion pairing with imbalanced populations. Within the ansatz,
thermodynamically stable gapless modes for both fermions and anti fermions are
seen for strong coupling in the BEC regime. We further investigate the effect
of fluctuations of the condensate field by treating it as a dynamical field and
generalize the BCS ansatz to include quanta of the condensate field also in a
boson fermion model with quartic self interaction of the condensate field. It
is seen that the critical temperature decreases with inclusion of fluctuations.


title: Swelling and shrinking kinetics of a lamellar gel phase

abstract:
  We investigate the swelling and shrinking of L_beta lamellar gel phases
composed of surfactant and fatty alcohol after contact with aqueous
poly(ethylene-glycol) solutions. The height change $\Delta h(t)$ is
diffusion-like with a swelling coefficient, S: $\Delta h = S \sqrt{t}$. On
increasing polymer concentration we observe sequentially slower swelling,
absence of swelling, and finally shrinking of the lamellar phase. This behavior
is summarized in a non-equilibrium diagram and the composition dependence of S
quantitatively described by a generic model. We find a diffusion coefficient,
the only free parameter, consistent with previous measurements.


title:
Prescribing Gauss curvature of surfaces in 3-dimensional spacetimes,
  Application to the Minkowski problem in the Minkowski space

abstract:
  We study the existence of surfaces with constant or prescribed Gauss
curvature in certain Lorentzian spacetimes. We prove in particular that every
(non-elementary) 3-dimensional maximal globally hyperbolic spatially compact
spacetime with constant non-negative curvature is foliated by compact spacelike
surfaces with constant Gauss curvature. In the constant negative curvature
case, such a foliation exists outside the convex core. The existence of these
foliations, together with a theorem of C. Gerhardt, yield several corollaries.
For example, they allow to solve the Minkowski problem in the 3-dimensional
Minkowski space for datas that are invariant under the action of a co-compact
Fuchsian group.


title: Lifting and restricting recollement data

abstract:
  We study the problem of lifting and restricting TTF triples (equivalently,
recollement data) for a certain wide type of triangulated categories. This,
together with the parametrizations of TTF triples given in "Parametrizing
recollement data", allows us to show that many well-known recollements of right
bounded derived categories of algebras are restrictions of recollements in the
unbounded level, and leads to criteria to detect recollements of general right
bounded derived categories. In particular, we give in Theorem 1 necessary and
sufficient conditions for a 'right bounded' derived category of a differential
graded(=dg) category to be a recollement of 'right bounded' derived categories
of dg categories. In Theorem 2 we consider the particular case in which those
dg categories are just ordinary algebras.


title: Primordial Non-Gaussianities of General Multiple Field Inflation

abstract:
  We perform a general study of the primordial scalar non-Gaussianities in
multi-field inflationary models in Einstein gravity. We consider models
governed by a Lagrangian which is a general function of the scalar fields and
their first spacetime derivatives. We use $\delta N$ formalism to relate scalar
fields and curvature perturbations. We calculate the explicit cubic order
perturbation action and the three-point function of curvature perturbation
evaluated at horizon-crossing. Under reasonable assumptions, in the limit of
small slow-varying parameters and a sound speed $c_s$ close to one, we find
that the non-Gaussianity is completely determined by these slow-varying
parameters and some other parameters determined by the structure of the
inflationary models. Our work generalizes previous results, and would be useful
to study non-Gaussianity in multi-field inflationary models that will be
constructed in the future.


title: Adaptivity in convolution models with partially known noise distribution

abstract:
  We consider a semiparametric convolution model. We observe random variables
having a distribution given by the convolution of some unknown density $f$ and
some partially known noise density $g$. In this work, $g$ is assumed
exponentially smooth with stable law having unknown self-similarity index $s$.
In order to ensure identifiability of the model, we restrict our attention to
polynomially smooth, Sobolev-type densities $f$, with smoothness parameter
$\beta$. In this context, we first provide a consistent estimation procedure
for $s$. This estimator is then plugged-into three different procedures:
estimation of the unknown density $f$, of the functional $\int f^2$ and
goodness-of-fit test of the hypothesis $H_0:f=f_0$, where the alternative $H_1$
is expressed with respect to $\mathbb {L}_2$-norm (i.e. has the form
$\psi_n^{-2}\|f-f_0\|_2^2\ge \mathcal{C}$). These procedures are adaptive with
respect to both $s$ and $\beta$ and attain the rates which are known optimal
for known values of $s$ and $\beta$. As a by-product, when the noise density is
known and exponentially smooth our testing procedure is optimal adaptive for
testing Sobolev-type densities. The estimating procedure of $s$ is illustrated
on synthetic data.


title:
Static Properties of Small Josephson Tunnel Junctions in a Transverse
  Magnetic Field

abstract:
  The magnetic field distribution in the barrier of small planar Josephson
tunnel junctions is numerically simulated in the case when an external magnetic
field is applied perpendicular to the barrier plane. The simulations allow for
heuristic analytical solutions for the Josephson static phase profile from
which the dependence of the maximum Josephson current on the applied field
amplitude is derived. The most common geometrical configurations are considered
and, when possible, the theoretical findings are compared with the experimental
data.


title: Extended Hartree-Fock method based on pair density functional theory

abstract:
  A practical electronic structure method in which a two-body functional is the
fundamental variable is constructed. The basic formalism of our method is
equivalent to Hartree-Fock density matrix functional theory [M. Levy in {\it
Density Matrices and Density Functionals}, Ed. R. Erdahl and V. H. Smith Jr.,
D. Reidel, (1987)]. The implementation of the method consists of solving
Hartree-Fock equations and using the resulting orbitals to calculate two-body
corrections to account for correlation. The correction terms are constructed so
that the energy of the system in the absence of external potentials can be made
to correspond to approximate expressions for the energy of the homogeneous
electron gas. In this work the approximate expressions we use are based on the
high-density limit of the homogeneous electron gas. Self-interaction is
excluded from the two-body functional itself. It is shown that our pair density
based functional does not suffer from the divergence present in many density
functionals when homogeneous scaling is applied. Calculations based on our pair
density functional lead to quantitative results for the correlation energies of
atomic test cases.


title: Composing Quantum Protocols in a Classical Environment

abstract:
  We propose a general security definition for cryptographic quantum protocols
that implement classical non-reactive two-party tasks. The definition is
expressed in terms of simple quantum-information-theoretic conditions which
must be satisfied by the protocol to be secure. The conditions are uniquely
determined by the ideal functionality F defining the cryptographic task to be
implemented. We then show the following composition result. If quantum
protocols pi_1,...,pi_k securely implement ideal functionalities F_1,...,F_k
according to our security definition, then any purely classical two-party
protocol, which makes sequential calls to F_1,...,F_k, is equally secure as the
protocol obtained by replacing the calls to F_1,...,F_k with the respective
quantum protocols pi_1,...,pi_k. Hence, our approach yields the minimal
security requirements which are strong enough for the typical use of quantum
protocols as subroutines within larger classical schemes. Finally, we show that
recently proposed quantum protocols for oblivious transfer and secure
identification in the bounded-quantum-storage model satisfy our security
definition, and thus compose in the above sense.


title: Quantum Dynamics on the Worldvolume from Classical su(n) Cohomology

abstract:
  A key symmetry of classical $p$-branes is invariance under worldvolume
diffeomorphisms. Under the assumption that the worldvolume, at fixed values of
the time, is a compact, quantisable K\"ahler manifold, we prove that the Lie
algebra of volume-preserving diffeomorphisms of the worldvolume can be
approximated by $su(n)$, for $n\to\infty$. We also prove, under the same
assumptions regarding the worldvolume at fixed time, that classical Nambu
brackets on the worldvolume are quantised by the multibrackets corresponding to
cocycles in the cohomology of the Lie algebra $su(n)$.


title:
Scaling of the von Neumann entropy across a finite temperature phase
  transition

abstract:
  The spectrum of the reduced density matrix and the temperature dependence of
the von Neumann entropy (VNE) are analytically obtained for a system of hard
core bosons on a complete graph which exhibits a phase transition to a
Bose-Einstein condensate at $T=T_c$. It is demonstrated that the VNE undergoes
a crossover from purely logarithmic at T=0 to purely linear in block size $n$
behaviour for $T\geq T_{c}$. For intermediate temperatures, VNE is a sum of two
contributions which are identified as the classical (Gibbs) and the quantum
(due to entanglement) parts of the von Neumann entropy.


title: Hall effect on the triangular lattice

abstract:
  We investigate the high frequency Hall effect on a two-dimensional triangular
lattice with nearest-neighbor hopping and a local Hubbard interaction. The
complete temperature and doping dependencies of the high-frequency Hall
coefficient $R_H$ are evaluated analytically and numerically for small,
intermediate, and strong interactions using various approximation schemes. We
find that $R_H$ follows the semiclassical $1/qn^*$ law near T=0, but exhibits a
striking $T$-linear behavior with an interaction- and doping-dependent slope at
high temperature. We compare our results with previous theories as well as Hall
measurements performed in the cobaltates.


title:
The Black Hole Accretion Disk in NGC 4258: One of Nature's Most
  Beautiful Dynamical Systems

abstract:
  In this talk I will summarize some of the work that the CfA group has done to
study the structure of the water masers in the accretion disk of NGC 4258. A
series of 18 epochs of VLBA data taken from 1997.3 to 2000.8 were used for this
study. The vertical distribution of maser features in the systemic group was
found to have a Gaussian distribution, as expected for hydrostatic equilibrium,
with a $\sigma$-width of 5.1 $\mu$as. If the disk is in hydrostatic
equilibrium, its temperature is about 600K. The systemic features exhibit a
small, but persistent, gradient in acceleration versus impact parameter. This
characteristic may indicate the presence of a spiral density wave rotating at
sub-Keplerian speed. A more precise understanding of the dynamical properties
of the disk is expected to lead to a more refined estimate of the distance to
the galaxy.


title:
GMASS Ultradeep Spectroscopy of Galaxies at z~2. III: The emergence of
  the color bimodality at z~2

abstract:
  The aim of this work is to study the evolution of the rest frame color
distribution of galaxies with the redshift, in particular in the critical
interval 1.4<z<3. We combine ultradeep spectroscopy from the GMASS project
(Galaxy Mass Assembly ultradeep Spectroscopic Survey) with GOODS multi-band
photometry (from optical to mid-infrared) to study a sample of 1021 galaxies up
to m(4.5$\mu$m)=23. We find that the distribution of galaxies in the (U-B)
color vs stellar mass plane is bimodal up to at least redshift z=2. We define a
mass complete sample of galaxies residing on the red-sequence, selecting
objects with log(M/M_{\odot})>10.1, and we study their morphological and
spectro-photometric properties. We show that the contribution to this sample of
early-type galaxies, defined as galaxies with a spheroidal morphology and no
star formation, decreases from 60-70% at z<0.5 down to ~50% at redshift z=2. At
z>2 we still find red galaxies in the mass complete sample, even if the
bimodality is not seen any more. About 25% of these red galaxies at z>2 are
passively evolving, with the bulk of their stars formed at redshift z>`3.


title:
Inverse Indefinite Spectral Problem for Second Order Differential
  Operator with Complex Periodoc Coefficients

abstract:
  The inverse problem for the Sturm- Liouville operator with complex periodic
potential and discontinuous coefficients on the axis is studied. Main
characteristics of the fundamental solutions are investigated, the spectrum of
the operator is studied. We give formulation of the inverse problem, prove a
uniqueness theorem and provide a constructive procedure for the solution of the
inverse problem.


title: Extended Debye Model for Molecular Magnets

abstract:
  Heat capacity data on Mn12 are fitted within the extended Debye model that
takes into account a continuum of optical modes as well as three different
speeds of sound.


title: A Hilbert--Mumford criterion for polystability in Kaehler geometry

abstract:
  Consider a Hamiltonian action by biholomorphisms of a compact Lie group $K$
on a Kaehler manifold $X$, with moment map $\mu:X\to\klie^*$. We characterize
which orbits of the complexified action of $G=K^{\CC}$ in $X$ intersect
$\mu^{-1}(0)$ in terms of the maximal weights $\lim_{t\to\infty}\la\mu(e^{\imag
ts}\cdot x),s\ra$, where $s$ belongs to the Lie algebra of $K$. We do not
impose any a priori restriction on the stabilizer of $x$. Assuming some mild
growth conditions on the action of $K$ on $X$, we view the maximal weights as
defining a maps $\lambda_x$ from the boundary at infinity of the symmetric
space $K\backslash G$ to $\RR\cup\{\infty\}$. We prove that $G\cdot x$ meets
$\mu^{-1}(0)$ if: (1) $\lambda_x$ is everywhere nonnegative, (2) any boundary
point $y$ such that $\lambda_x(y)=0$ can be connected with a geodesic in
$K\backslash G$ to another boundary point $y'$ satisfying $\lambda_x(y')=0$. We
also prove that $\lambda_{g\cdot x}(y)=\lambda_x(y\cdot g)$ for any $g\in G$
and $y\in \partial_{\infty}(K\backslash G)$.


title: Underground Muon Counters as a Tool for Composition Analyses

abstract:
  The transition energy from galactic to extragalactic cosmic ray sources is
still uncertain, but it should be associated either with the region of the
spectrum known as the second knee or with the ankle. The baseline design of the
Pierre Auger Observatory was optimized for the highest energies. The surface
array is fully efficient above $3 \times 10^{18}$ eV and, even if the hybrid
mode can extend this range below $10^{18}$ eV, the second knee and a
considerable portion of the wide ankle structure are left outside its operating
range. Therefore, in order to encompass these spectral features and gain
further insight into the cosmic ray composition variation along the transition
region, enhancements to the surface and fluorescence components of the baseline
design are being implemented that will lower the full efficiency regime of the
Observatory down to $\sim 10^{17}$ eV. The surface enhancements consist of a
graded infilled area of standard Auger water Cherenkov detectors deployed in
two triangular grids of 433 m and 750 m of spacing. Each surface station inside
this area will have an associated muon counter detector. The fluorescence
enhancement, on the other hand, consists of three additional fluorescence
telescopes with higher elevation angle ($30^\circ-58^\circ$) than the ones in
operation at present. The aim of this paper is threefold. We study the effect
of the segmentation of the muon counters and find an analytical expression to
correct for the under counting due to muon pile-up. We also present a detailed
method to reconstruct the muon lateral distribution function for the 750 m
spacing array. Finally, we study the mass discrimination potential of a new
parameter, the number of muons at 600 m from the shower axis, obtained by
fitting the muon data with the above mentioned reconstruction method.


title: VLBA determinations of the distances to nearby star-forming regions

abstract:
  Using phase-referenced multi-epoch Very Long Baseline Array observations, we
have measured the trigonometric parallax of several young stars in the Taurus
and Ophiuchus star-forming regions with unprecedented accuracy. The mean
distance to the Taurus complex was found to be about 140 pc, and its depth
around 20 pc, comparable to the linear extent of Taurus on the plane of the
sky. In Ophiuchus, 4 sources were observed so far. Two of them were found to be
at about 160 pc (the distance traditionally attributed to Ophiuchus), while the
other 2 are at about 120 pc. Since the entire Ophiuchus complex is only a few
parsecs across, this difference is unlikely to reflect the depth of the region.
Instead, we argue that two physically unrelated sites of star-formation are
located along the line of sight toward Ophiuchus.