title:
Negative differential resistance in molecular junctions: application to
  graphene ribbon junctions

abstract:
  Using self-consistent calculations based on Non-Equilibrium Green's Function
(NEGF) formalism, the origin of negative differential resistance (NDR) in
molecular junctions and quantum wires is investigated. Coupling of the molecule
to electrodes becomes asymmetric at high bias due to asymmetry between its
highest occupied molecular orbital (HOMO) and lowest unoccupied molecular
orbital (LUMO) levels. This causes appearance of an asymmetric potential
profile due to a depletion of charge and reduction of screening near the source
electrode. With increasing bias, this sharp potential drop leads to an enhanced
localization of the HOMO and LUMO states in different parts of the system. The
reduction in overlap, caused by localization, results in a significant
reduction in the transmission coefficient and current with increasing bias. An
atomic chain connected to two Graphene ribbons was investigated to illustrate
these effects. For a chain substituting a molecule, an even-odd effect is also
observed in the NDR characteristics.


title: Optimal Investment Strategy to Minimize Occupation Time

abstract:
  We find the optimal investment strategy to minimize the expected time that an
individual's wealth stays below zero, the so-called {\it occupation time}. The
individual consumes at a constant rate and invests in a Black-Scholes financial
market consisting of one riskless and one risky asset, with the risky asset's
price process following a geometric Brownian motion. We also consider an
extension of this problem by penalizing the occupation time for the degree to
which wealth is negative.


title: Generic ordinarity for semi-stable fibration

abstract:
  In this paper, we proved that, for a semi-stable fibration of a proper smooth
surface to a proper smooth curve over a field of positive characteristic, if
the generic fiber is ordinary, then the semi-positivity theorem holds. As an
application, we constrcuted a counterexample to Parshin's conjecture on the
Miyaoka-Yau inequality.


title: Clustering of supernova Ia host galaxies

abstract:
  For the first time the cross-correlation between type Ia supernova host
galaxies and surrounding field galaxies is measured using the Supernova Legacy
Survey sample. Over the z=0.2 to 0.9 redshift range we find that supernova
hosts are correlated an average of 60% more strongly than similarly selected
field galaxies over the 3-100 arcsec range and about a factor of 3 more
strongly below 10 arcsec. The correlation errors are empirically established
with a jackknife analysis of the four SNLS fields. The hosts are more
correlated than the field at a significance of 99% in the fitted amplitude and
slope, with the point-by-point difference of the two correlation functions
having a reduced $\chi^2$ for 8 degrees of freedom of 4.3, which has a
probability of random occurrence of less than 3x10^{-5}. The correlation angle
is 1.5+/-0.5 arcsec, which deprojects to a fixed co-moving correlation length
of approximately 6.5+/- 2/h mpc. Weighting the field galaxies with the mass and
star formation rate supernova frequencies of the simple A+B model produces good
agreement with the observed clustering. We conclude that these supernova
clustering differences are primarily the expected outcome of the dependence of
supernova rates on galaxy masses and stellar populations with their clustering
environment.


title:
Alignment of the Pixel and SCT Modules for the 2004 ATLAS Combined Test
  Beam

abstract:
  A small set of final prototypes of the ATLAS Inner Detector silicon tracker
(Pixel and SCT) were used to take data during the 2004 Combined Test Beam. Data
were collected from runs with beams of different flavour (electrons, pions,
muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent
methods were used to align the silicon modules. The corrections obtained were
validated using the known momenta of the beam particles and were shown to yield
consistent results among the different alignment approaches. From the residual
distributions, it is concluded that the precision attained in the alignment of
the silicon modules is of the order of 5 micrometers in their most precise
coordinate.


title:
Coupling of morphology to surface transport in ion-beam irradiated
  surfaces. I. Oblique incidence

abstract:
  We propose and study a continuum model for the dynamics of amorphizable
surfaces undergoing ion-beam sputtering (IBS) at intermediate energies and
oblique incidence. After considering the current limitations of more standard
descriptions in which a single evolution equation is posed for the surface
height, we overcome (some of) them by explicitly formulating the dynamics of
the species that transport along the surface, and by coupling it to that of the
surface height proper. In this we follow recent proposals inspired by
``hydrodynamic'' descriptions of pattern formation in aeolian sand dunes and
ion-sputtered systems. From this enlarged model, and by exploiting the
time-scale separation among various dynamical processes in the system, we
derive a single height equation in which coefficients can be related to
experimental parameters. This equation generalizes those obtained by previous
continuum models and is able to account for many experimental features of
pattern formation by IBS at oblique incidence, such as the evolution of the
irradiation-induced amorphous layer, transverse ripple motion with non-uniform
velocity, ripple coarsening, onset of kinetic roughening and other.
Additionally, the dynamics of the full two-field model is compared with that of
the effective interface equation.

categories: cond-mat.mtrl-sci cond-mat.stat-mech math-ph math.MP nlin.PS


title: Unirational Surfaces on the Noether Line

abstract:
  We show that among simply connected surfaces of general type unirationality
is a common feature, even when fixing the positive characteristic or numerical
invariants. To do so, we construct unirational Horikawa surfaces in abundance.


title: Low pole order frames on vertical jets of the universal hypersurface

abstract:
  Of the two techniques introduced by Bloch, Green-Griffiths and developed by
Siu, Demailly to establish Kobayashi hyperbolicity of generic high degree
complex algebraic hypersurfaces X in P^(n+1), the second one, initiated by
Clemens, Ein, Voisin and developed by Siu, Paun, Rousseau consists in
constructing meromorphic frames on the space of the so-called vertical k-jets
J_vert^k (X_univ) of the universal hypersurface X_univ parametrizing all X in
P^(n+1) of degree d. In 2004, Siu announced that there exists a constant c_n
such that the twisting of the tangent bundle to J_vert^n (X_univ) by O (c_n) is
globally generated (frame property). The present article provides c_n = (n^2 +
5n) / 2, recovering c_2 = 7 (Paun), c_3 = 12 (Rousseau). Applications to
effective degree estimates for algebraic degeneracy or hyperbolicity are
expected, especially in dimension n = 4, granted that the Demailly-Semple
algebra of jet polynomials invariant under reparametrization and under a
certain unipotent action is, for n = k = 4, generated by 16 fundamental
bi-invariants enjoying 41 groebnerized syzygies.


title: Phase diagram of the asymmetric Hubbard model

abstract:
  The ground-state phase diagram of the asymmetric Hubbard model is studied in
one and two dimensions by a well-controlled numerical method. The method allows
to calculate directly the probabilities of particular phases in the approximate
ground-state and thus to specify the stability domains corresponding to phases
with the highest probabilities. Depending on the electron filling $n$ and the
magnitude of the asymmetry $t_f/t_d$ between the hopping integrals of $f$ and
$d$ electrons two different scenarios in formation of ground states are
observed. At low electron fillings ($n\leq 1/3$) the ground states are always
phase segregated in the limit of strong asymmetry ($t_d\gg t_f$). With
decreasing asymmetry the system undergoes a transition to the phase separated
state and then to the homogeneous state. For electron fillings $n>1/3 $ and
weak Coulomb interactions the ground state is homogeneous for all values of
asymmetry, while for intermediate and strong interactions the system exhibits
the same sequence of phase transitions as for $n$ small. Moreover, it is shown
that the segregated phase is significantly stabilized with increasing electron
filling, while the separated phases disappear gradually from the ground-state
phase diagrams.


title: Running minimal flavor violation

abstract:
  We consider the flavor structure of the minimal supersymmetric standard model
(MSSM) in the framework of `minimal flavor violation' (MFV). We show that, if
one imposes the MFV structure at some scale, to a good accuracy the MFV
decomposition works at all other scales. That is, quantum effects can be
described by running coefficients of the MFV decomposition. We find that the
coefficients get driven to non-trivial fixed points.


title:
Observation of magnetic field lines in the vicinity of a superconductor
  with the naked eye

abstract:
  Meissner effect and pinning effect are clearly observed with the naked eye. A
GdBaCuO high-temperature superconductor (HTS) disk fabricated by Nippon Steel
Corporation, a 100mm cubic NdFeB sintered magnet, and iron wires coated by
colored are used. When the HTS is put in the magnetic field of the magnet, it
can be observed by the wires that the magnetic field lines are excluded from
the superconductor (Meissner effect) as well as are pinned in the
superconductor (pinning effect).


title: Neutrino Counter Nuclear Weapon

abstract:
  Radiations produced by neutrino-antineutrino annihilation at the Z0 pole can
be used to heat up the primary stage of a thermonuclear warhead and can in
principle detonate the device remotely. Neutrino-antineutrino annihilation can
also be used as a tactical assault weapon to target hideouts that are
unreachable by conventional means.


title:
The effect of internal pressure on the tetragonal to monoclinic
  structural phase transition in ReOFeAs: the case of NdOFeAs

abstract:
  We report the temperature dependent x-ray powder diffraction of the
quaternary compound NdOFeAs (also called NdFeAsO) in the range between 300 K
and 95 K. We have detected the structural phase transition from the tetragonal
phase, with P4/nmm space group, to the orthorhombic or monoclinic phase, with
Cmma or P112/a1 (or P2/c) space group, over a broad temperature range from 150
K to 120 K, centered at T0 ~137 K. Therefore the temperature of this structural
phase transition is strongly reduced, by about ~30K, by increasing the internal
chemical pressure going from LaOFeAs to NdOFeAs. In contrast the
superconducting critical temperature increases from 27 K to 51 K going from
LaOFeAs to NdOFeAs doped samples. This result shows that the normal striped
orthorhombic Cmma phase competes with the superconducting tetragonal phase.
Therefore by controlling the internal chemical pressure in new materials it
should be possible to push toward zero the critical temperature T0 of the
structural phase transition, giving the striped phase, in order to get
superconductors with higher Tc.


title: New Relations for Gauge-Theory Amplitudes

abstract:
  We present an identity satisfied by the kinematic factors of diagrams
describing the tree amplitudes of massless gauge theories. This identity is a
kinematic analog of the Jacobi identity for color factors. Using this we find
new relations between color-ordered partial amplitudes. We discuss applications
to multi-loop calculations via the unitarity method. In particular, we
illustrate the relations between different contributions to a two-loop
four-point QCD amplitude. We also use this identity to reorganize gravity tree
amplitudes diagram by diagram, offering new insight into the structure of the
KLT relations between gauge and gravity tree amplitudes. This can be used to
obtain novel relations similar to the KLT ones. We expect this to be helpful in
higher-loop studies of the ultraviolet properties of gravity theories.


title: New Schwinger-Dyson equations for non-Abelian gauge theories

abstract:
  We show that the application of the pinch technique to the conventional
Schwinger-Dyson equations for the gluon propagator, gluon-quark vertex, and
three-gluon vertex, gives rise to new equations endowed with special
properties. The new series coincides with the one obtained in the Feynman gauge
of the background field method, thus capturing the extensive gauge
cancellations implemented by the pinch technique at the level of individual
Green's functions. Its building blocks are the fully dressed pinch technique
Green's functions obeying Abelian all-order Ward identities instead of the
Slavnov-Taylor identites satisfied by their conventional counterparts. As a
result, and contrary to the standard case, the new series can be truncated
gauge invariantly at any order in the dressed loop expansion. The construction
is streamlined by resorting to the Batalin-Vilkovisky formalism which allows
for a concise treatment of all the quantities appearing in the intermediate
steps. The theoretical and phenomenological implications of this novel
non-perturbative framework are discussed in detail.


title:
Small violations of unitarity, the phase in Bs mixing and visible t->cZ
  decays at the LHC

abstract:
  We show that it is possible to accommodate the observed size of the phase in
$B^0_s$--$\bar B^0_s$, mixing in the framework of a model with violation of
$3\times 3$ unitarity. This violation is associated to the presence of a new
$Q=2/3$ isosinglet quark $T$, which mixes both with $t$ and $c$ and has a mass
not exceeding 500 GeV. The crucial point is the fact that this framework allows
for $\chi\equiv\arg(-V_{ts}V_{cb}V_{tb}^*V_{cs}^*)$ of order $\lambda$, to be
contrasted with the situation in the Standard Model, where $\chi$ is
constrained to be of order $\lambda^2$. We point out that this scenario implies
rare top decays $t\to cZ$ at a rate observable at the LHC and $|V_{tb}|$
significantly different from unity. In this framework, one may also account for
the observed size of $D^0$--$\bar D^0$ mixing without having to invoke long
distance contributions. It is also shown that in the present scenario, the
observed size of $D^0$--$\bar D^0$ mixing constrains
$\chi^\prime\equiv\arg(-V_{cd}V_{us}V_{cs}^*V_{ud}^*)$ to be of order
$\lambda^4$, which is significantly smaller than what is allowed in generic
models with violations of $3\times 3$ unitarity.


title: Cloud and Star Formation in Disk Galaxy Models with Feedback

abstract:
  We include feedback in global hydrodynamic simulations in order to study the
star formation properties, and gas structure and dynamics, in models of
galactic disks. We extend previous models by implementing feedback in
gravitationally bound clouds: momentum is injected at a rate proportional to
the star formation rate. This mechanical energy disperses cloud gas back into
the surrounding ISM, truncating star formation in a given cloud, and raising
the overall level of ambient turbulence. Propagating star formation can however
occur as expanding shells collide, enhancing the density and triggering new
cloud and star formation. By controlling the momentum injection per massive
star and the specific star formation rate in dense gas, we find that the
negative effects of high turbulence outweigh the positive ones, and in net
feedback reduces the fraction of dense gas and thus the overall star formation
rate. The properties of the large clouds that form are not, however, very
sensitive to feedback, with cutoff masses of a few million solar masses,
similar to observations. We find a relationship between the star formation rate
surface density and the gas surface density with a power law index ~2 for our
models with the largest dynamic range, consistent with theoretical expectations
for our model of disk flaring. We point out that the value of the
"Kennicutt-Schmidt" index depends on the thickness of the disk. With our simple
feedback prescription (a single combined star formation event per cloud), we
find that global spiral patterns are not sustained; less correlated feedback
and smaller scale turbulence appear to be necessary for spiral patterns to
persist.


title: Semi-stable fibration of generic p-rank 0

abstract:
  In this paper, we proved that, for a semi-stable fibration of a proper smooth
surface to a proper smooth curve over a filed of positive characteristic, if
the p-rank of the generic fiber is 0, then the base change of the fibration by
a sufficiently many iterative Frobenius morphism of the base curve violates the
semi-positivity theorem. As an application, we suggest a statement on a
distribution of p-ranks of reductions for a certain non-closed point in the
moduli space over a number field.


title:
Magnetic reversal under external field and current-driven domain wall
  motion in (Ga,Mn)As: influence of extrinsic pinning

abstract:
  We investigate the anisotropy of magnetic reversal and current-driven domain
wall motion in annealed Ga_0.95Mn_0.05As thin films and Hall bar devices with
perpendicular magnetic anisotropy. Hall bars with current direction along the
[110] and [1-10] crystallographic axes are studied. The [110] device shows
larger coercive field than the [1-10] device. Strong anisotropy is observed
during magnetic reversal between [110] and [1-10] directions. A power law
dependence is found for both devices between the critical current (JC) and the
magnetization (M), with J_C is proportional to M^2.6. The domain wall motion is
strongly influenced by the presence of local pinning centres.


title:
The Relation between Approximation in Distribution and Shadowing in
  Molecular Dynamics

abstract:
  Molecular dynamics refers to the computer simulation of a material at the
atomic level. An open problem in numerical analysis is to explain the apparent
reliability of molecular dynamics simulations. The difficulty is that
individual trajectories computed in molecular dynamics are accurate for only
short time intervals, whereas apparently reliable information can be extracted
from very long-time simulations. It has been conjectured that long molecular
dynamics trajectories have low-dimensional statistical features that accurately
approximate those of the original system. Another conjecture is that numerical
trajectories satisfy the shadowing property: that they are close over long time
intervals to exact trajectories but with different initial conditions. We prove
that these two views are actually equivalent to each other, after we suitably
modify the concept of shadowing. A key ingredient of our result is a general
theorem that allows us to take random elements of a metric space that are close
in distribution and embed them in the same probability space so that they are
close in a strong sense. This result is similar to the Strassen-Dudley Theorem
except that a mapping is provided between the two random elements. Our results
on shadowing are motivated by molecular dynamics but apply to the approximation
of any dynamical system when initial conditions are selected according to a
probability measure.


title:
Embedding groups of class two and prime exponent in capable and
  non-capable groups

abstract:
  We show that if $G$ is any $p$-group of class at most two and exponent $p$,
then there exist groups $G_1$ and $G_2$ of class two and exponent $p$ that
contain $G$, neither of which can be expressed as a central product, and with
$G_1$ capable and $G_2$ not capable. We provide upper bounds for ${\rm
rank}(G_i^{\rm ab})$ in terms of ${\rm rank}(G^{\rm ab})$ in each case.


title:
Faisceaux sans torsion et faisceaux quasi localement libres sur les
  courbes multiples primitives

abstract:
  This paper is devoted to the study of some coherent sheaves on non reduced
curves that can be locally embedded in smooth surfaces. If Y is such a curve
then there is a filtration by subschemes C_i such that C_1 is the reduced curve
associated to Y, and that for every P in C, if z is an equation of C_1 in the
local ring of Y at P, then (z^i) is the ideal of C_i. A coherent sheaf on Y is
called torsion free if it does not have any non zero subsheaf with finite
support. We prove that torsion free sheaves are reflexive. We study then the
quasi locally free sheaves, i.e. sheaves which are locally isomorphic to direct
sums of the structure sheaves of the C_i. We define an invariant for these
sheaves, the complete type, and prove the irreducibility of the set of sheaves
of given complete type. We study the generic quasi locally free sheaves, with
applications to the moduli spaces of stable sheaves on Y.


title: A Wave Function approach to dissipative processes

abstract:
  Due to growing interest in quantum measurement, control and feedback, we
reproduce a manuscript from 1992, presenting a simple physical and mathematical
derivation of stochastic differential equations for wave functions of probed
quantum systems. V. P. Belavkins seminal quantum filtering theory with similar
equations, developed in the 1980es, was not known to the authors at the time of
writing of the present manuscript.


title: Kac-Moody Extensions of 3-Algebras and M2-branes

abstract:
  We study the 3-algebraic structure involved in the recently shown M2-branes
worldvolume gauge theories. We first extend an arbitrary finite dimensional
3-algebra into an infinite dimensional 3-algebra by adding a mode number to
each generator. A unique central charge in the algebra of gauge transformations
appears naturally in this extension. We present an infinite dimensional
extended 3-algebra with a general metric and also a different extension with a
Lorentzian metric. We then study ordinary finite dimensional 3-algebras with
different signatures of the metric, focusing on the cases with a negative
eigenvalue and the cases with a zero eigenvalue. In the latter cases we present
a new algebra, whose corresponding theory is a decoupled abelian gauge theory
together with a free theory with global gauge symmetry, and there is no
negative kinetic term from this algebra.


title: Canonical quantization of Plebanski gravity in diagonal variables

abstract:
  In this paper we have carried out a transformation from Ashtekar's theory of
GR into a reduced theory where the physical degrees of freedom are explicit. We
have performed the canonical analysis, computed the classical dynamics and have
performed a quantization on this reduced space, constructing a Hilbert space of
states for vanishing cosmological constant. Finally, we have clarified the
canonical structure of the dual theory in relation to the original Ashtekar
theory.


title: From model dynamics to oscillating dark energy parameterisation

abstract:
  We develop here a relatively simple description of dark energy based on the
dynamics of non-minimally coupled to gravity phantom scalar field which, in
limit, corresponds to cosmological constant. The dark energy equation of state,
obtained directly from the dynamics of the model, turns out to be an
oscillatory function of the scale factor. This parameterisation is compared to
other possible dark energy parameterisations, among them, the most popular one,
linear in the scale factor. We use the Bayesian framework for model selection
and make a comparison in the light of SN Ia, CMB shift parameter, BAO A
parameter, observational H(z) and growth rate function data. We find that there
is evidence to favour a parameterisation with oscillations over {\it a priori}
assumed linear one.


title:
Azimuthal angle dependence of di-jet production in unpolarized hadron
  scattering

abstract:
  We study the azimuthal angular dependence of back-to-back di-jet production
in unpolarized hadron scattering $H_A+H_B \to J_1 + J_2 +X$, arising from the
product of two Boer-Mulders functions, which describe the transverse spin
distribution of quarks inside an unpolarized hadron. We find that when the
di-jet is of two identical quarks ($J_q+J_q$) or a quark-antiquark pair
($J_q+J_{\bar{q}}$), there is a $\cos \delta \phi$ angular dependence of the
di-jet, with $\delta \phi=\phi_1-\phi_2$, and $\phi_1$ and $\phi_2$ are the
azimuthal angles of the two individual jets. In the case of $J_q+J_q$
production, we find that there is a color factor enhancement in the gluonic
cross-section, compared with the result from the standard generalized parton
model. We estimate the $\cos \delta \phi$ asymmetry of di-jet production at
RHIC, showing that the color factor enhancement in the angular dependent of
$J_q+J_q$ production will reverse the sign of the asymmetry.


title: Every hierarchy of beliefs is a type

abstract:
  When modeling game situations of incomplete information one usually considers
the players' hierarchies of beliefs, a source of all sorts of complications.
Hars\'anyi (1967-68)'s idea henceforth referred to as the "Hars\'anyi program"
is that hierarchies of beliefs can be replaced by "types". The types constitute
the "type space". In the purely measurable framework Heifetz and Samet (1998)
formalize the concept of type spaces and prove the existence and the uniqueness
of a universal type space. Meier (2001) shows that the purely measurable
universal type space is complete, i.e., it is a consistent object. With the aim
of adding the finishing touch to these results, we will prove in this paper
that in the purely measurable framework every hierarchy of beliefs can be
represented by a unique element of the complete universal type space.


title: First Order Phase Transition in Quantum Paraelectrics

abstract:
  We discuss the nature of pressure induced phase transitions in standard
Quantum Paraelectrics near quantum critical point. From a microscopic theory we
first show that near the critical point the transition temperature $T_c(p)$
varies as $ (1-p/p_c)^\xi$ with $\xi={1/2}$. Within the Landau scheme, it is
shown that for $\xi \leq 1$, a condition satisfied by most quantum
paraelectrics the transition is inevitably first order in nature. The present
analysis is valid for non-polar impurity induced transitions in these materials
and is supported by some recent experiment.


title: Short wavelength regenerative amplifier free electron lasers

abstract:
  In this paper we discuss extending the operating wavelength range of tunable
Regenerative Amplifier FELs to shorter wavelengths than current design
proposals, notably into the XUV regions of the spectrum and beyond where the
reflectivity of broadband optics is very low. Simulation studies are presented
which demonstrate the development of good temporal coherence in generic systems
with a broadband radiation feedback of less than one part in ten thousand.


title:
Confirmation of the Electron Cyclotron Maser Instability as the Dominant
  Source of Radio Emission from Very Low Mass Stars and Brown Dwarfs

abstract:
  We report on radio observations of the M8.5 dwarf LSR J1835+3259 and the L3.5
dwarf 2MASS J00361617+1821104, which provide the strongest evidence to date
that the electron cyclotron maser instability is the dominant mechanism
producing radio emission in the magnetospheres of ultracool dwarfs. As has
previously been reported for the M9 dwarf TVLM 513-46546, periodic pulses of
100% circularly polarized, coherent radio emission are detected from both
dwarfs with periods of 2.84 +/- 0.01 and 3.08 +/- 0.05 hours respectively for
LSR J1835+3259 and 2MASS J00361617+1821104. Importantly, periodic unpolarized
radio emission is also detected from 2MASS J00361617+1821104, and brightness
temperature limitations rule out gyrosynchrotron radiation as a source of this
radio emission. The unpolarized emission from this and other ultracool dwarfs
is also attributed to electron cyclotron maser emission, which has become
depolarized on traversing the ultracool dwarf magnetosphere, possibly due to
propagations effects such as scattering. Based on available v sin i data in the
literature and rotation periods derived from the periodic radio data for the
three confirmed sources of electron cyclotron maser emission, TVLM 513-46546,
LSR J1835+3259 and 2MASS J00361617+1821104, we determine that the rotation axes
of all three dwarfs are close to perpendicular to our line of sight. This
suggests a possible geometrical selection effect due to the inherent
directivity of electron cyclotron maser emission, that may account for the
previously reported relationship between radio activity and v sin i observed
for ultracool dwarfs. We also determine the radius of the dwarf LSR J1835+3259
to be > 0.117 +/- 0.012 R_Sol. (abridged)


title:
The ultraluminous X-ray source NGC 1313 X-2 - Its optical counterpart
  and environment

abstract:
  NGC 1313 X-2 is one of the brightest ultraluminous X-ray sources in the sky,
at both X-ray and optical wavelengths; therefore, quite a few studies of
available ESO VLT and HST data have appeared in the literature. Here, we
present our analysis of VLT/FORS1 and HST/ACS photometric data, confirming the
identification of the B ~ 23 mag blue optical counterpart. We show that the
system is part of a poor cluster with an age of 20 Myr, leading to an upper
mass limit of some 12 M_sun for the mass donor. We attribute the different
results with respect to earlier studies to the use of isochrones in the F435W
and F555W HST/ACS photometric system that appear to be incompatible with the
corresponding Johnson B and V isochrones. The counterpart exhibits significant
photometric variability of about 0.2 mag amplitude, both between the two HST
observations and during the one month of monitoring with the VLT. This includes
variability within one night and suggests that the light is dominated by the
accretion disk in the system and not by the mass donor.


title:
Detections of Lyman Continuum from Star-forming Galaxies at z~3 Through
  Subaru/Suprime-Cam Narrow-band Imaging

abstract:
  Knowing the amount of ionizing photons from young star-forming galaxies is of
particular importance to understanding the reionization process. Here we report
initial results of Subaru/Suprime-Cam deep imaging observation of the SSA22
proto-cluster region at z=3.09, using a special narrow-band filter to optimally
trace Lyman continuum (LyC) from galaxies at z~3. The unique wide field-of-view
of Suprime-Cam enabled us to search for ionizing photons from 198 galaxies (73
Lyman break galaxies (LBGs) and 125 Ly-alpha emitters (LAEs)) with
spectroscopically measured redshifts z~3.1. We detected LyC from 7 LBGs, as
well as from 10 LAE candidates. Some of the detected galaxies show significant
spatial offsets of LyC from non-ionizing UV emission. For some LBGs the
observed non-ionizing UV to LyC flux density ratios are smaller than values
expected from population synthesis models with a standard Salpeter initial mass
function (IMF) with moderate dust attenuation (which is suggested from the
observed UV slopes), even if we assume very transparent IGM along the
sightlines of these objects. This implies an intrinsically bluer spectral
energy distribution, e.g, that produced by a top-heavy IMF, for these LBGs. The
observed flux desity ratios of non-ionizing UV to LyC of 7 detected LBGs range
from 2.4 to 23.8 and the median is 6.6. The observed flux density ratios of the
detected LAEs are even smaller than LBGs, if they are truly at z~3.1. We find
that the median value of the flux density ratio for the deteced LBGs suggest
that their escape fractions is likely to be higher than 4%, if the LyC escape
is isotropic. The results imply that some of the LBGs in the proto-cluster at
z~3 have the escape fraction significantly higher than that of galaxies (in a
general field) at z~1 studied previously.


title: Dynamics of Biased Domain Walls and the Devaluation Mechanism

abstract:
  We study the evolution of biased domain walls in the early universe. We
explicitly discuss the roles played by the surface tension and volume pressure
in the evolution of the walls, and quantify their effects by looking at the
collapse of spherical wall solutions. We then apply our results to a particular
mechanism, known as the devaluation scenario, in which the dynamics of biased
domain walls was suggested as a possible solution to the cosmological constant
problem. Our results indicate that devaluation will in general lead to values
of the cosmological constant that differ by several orders of magnitude from
the observationally inferred value, $\rho^{1/4}_{vac}\sim10^{-3} \rm eV$. We
also argue that the reasons behind this are not specific to a particular
realization, and are expected to persist in any scenario of this kind, except
if a low energy cut-off on the spectra of vacuum energy densities, of the order
of the critical density at the present time, is postulated. This implies that
any such scenario will require a fine-tuning similar to the usual one.


title: Are sterile neutrinos consistent with clusters, the CMB and MOND?

abstract:
  If a single sterile neutrino exists such that $m_{\nu_s}\sim11eV$, it can
serendipitously solve all outstanding issues of the Modified Newtonian
Dynamics. With it one can explain the dark matter of galaxy clusters without
influencing individual galaxies, match the angular power spectrum of the cosmic
microwave background and potentially fit the matter power spectrum. This model
is flat with $\Omega_{\nu_s}\sim0.23$ and the usual baryonic and dark energy
components, thus the Universe has the same expansion history as the $\lcdm$
model and only differs at the galactic scale where the Modified Dynamics
outperforms $\lcdm$ significantly.


title:
Intragroup diffuse light in compact groups of galaxies II. HCG 15, 35
  and 51

abstract:
  This continuing study of intragroup light in compact groups of galaxies aims
to establish new constraints to models of formation and evolution of galaxy
groups, specially of compact groups, which are a key part in the evolution of
larger structures, such as clusters. In this paper we present three additional
groups (HCG 15, 35 and 51) using deep wide field $B$ and $R$ band images
observed with the LAICA camera at the 3.5m telescope at the Calar Alto
observatory (CAHA). This instrument provides us with very stable flatfielding,
a mandatory condition for reliably measuring intragroup diffuse light. The
images were analyzed with the OV\_WAV package, a wavelet technique that allows
us to uncover the intragroup component in an unprecedented way. We have
detected that 19, 15 and 26% of the total light of HCG 15, 35 and 51,
respectively, is in the diffuse component, with colours that are compatible
with old stellar populations and with mean surface brightness that can be as
low as $28.4 {\rm B mag arcsec^{-2}}$. Dynamical masses, crossing times and
mass to light ratios were recalculated using the new group parameters. Also
tidal features were analyzed using the wavelet technique.


title: Dark matter annihilation effects on the first stars

abstract:
  We study the effects of WIMP dark matter (DM) on the collapse and evolution
of the first stars in the Universe. Using a stellar evolution code, we follow
the pre-Main Sequence (MS) phase of a grid of metal-free stars with masses in
the range 5-600 solar mass forming in the centre of a 1e6 solar mass halo at
redhisft z=20. DM particles of the parent halo are accreted in the
proto-stellar interior by adiabatic contraction and scattering/capture
processes, reaching central densities of order 1e12 GeV/cm3 at radii of the
order of 10 AU. Energy release from annihilation reactions can effectively
counteract the gravitational collapse, in agreement with results from other
groups. We find this stalling phase (known as "dark" star) is transients and
lasts from 2.1e3 yr (M=600 solar mass) to 1.8e4 yr (M=9 solar mass). Later in
the evolution, DM scattering/capture rate becomes high enough that energy
deposition from annihilations significantly alters the pre-MS evolution of the
star in a way that depends on DM (i) velocity dispersion, (ii) density, (iii)
elastic scattering cross section with baryons. For our fiducial set of
parameters (10 km/s, 1e11 GeV/cm3, 1e-38 cm2) we find that the evolution of
stars of mass lower than 40 solar masses "freezes" on the HR diagram before
reaching the ZAMS. Stars with bigger masses manage to ignite nuclear reactions;
however, DM "burning" prolonges their lifetimes by a factor 2 (5) for a 600
(40) solar mass star.


title: Extrinsic and intrinsic nucleosome positioning signals

abstract:
  In eukaryotic genomes, nucleosomes function to compact DNA and to regulate
access to it both by simple physical occlusion and by providing the substrate
for numerous covalent epigenetic tags. While nucleosome positions in vitro are
determined by sequence alone, in vivo competition with other DNA-binding
factors and action of chromatin remodeling enzymes play a role that needs to be
quantified. We developed a biophysical model for the sequence dependence of DNA
bending energies, and validated it against a collection of in vitro free
energies of nucleosome formation and a nucleosome crystal structure; we also
successfully designed both strong and poor histone binding sequences ab initio.
For in vivo data from S.cerevisiae, the strongest positioning signal came from
the competition with other factors. Based on sequence alone, our model predicts
that functional transcription factor binding sites have a tendency to be
covered by nucleosomes, but are uncovered in vivo because functional sites
cluster within a single nucleosome footprint, making transcription factors bind
cooperatively. Similarly a weak enhancement of nucleosome binding in the TATA
region for naked DNA becomes a strong depletion when the TATA-binding protein
is included, in quantitative agreement with experiment. Predictions at specific
loci were also greatly enhanced by including competing factors. Our physically
grounded model distinguishes multiple ways in which genomic sequence can
influence nucleosome positions and thus provides an alternative explanation for
several important experimental findings.


title:
Simultaneous Determination of the Cosmic Ray Ionization Rate and
  Fractional Ionization in DR21(OH)

abstract:
  We present a new method for the simultaneous calculation of the cosmic ray
ionization rate, zeta(H2), and the ionization fraction, chi(e), in dense
molecular clouds. A simple network of chemical reactions dominant in the
creation and destruction of HCNH+ and HCO+ is used in conjunction with observed
pairs of rotational transitions of several molecular species in order to
determine the electron abundance and the H3+ abundance. The cosmic ray
ionization rate is then calculated by taking advantage of the fact that, in
dark clouds, it governs the rate of creation of H3+. We apply this technique to
the case of the star-forming region DR21(OH), where we successfully detected
the (J=3-2) and (J=4-3) rotational transitions of HCNH+. We also determine the
C and O isotopic ratios in this source to be 12C/13C=63+-4 and 16O/18O=318+-64,
which are in good agreement with previous measurements in other clouds. The
significance of our method lies in the ability to determine N(H3+) and chi(e)
directly from observations, and estimate zeta(H2) accordingly. Our results,
zeta(H2)=3.1x10^(-18) 1/s and chi(e)=3.2x10^(-8), are consistent with recent
determinations in other objects.


title:
The Star Formation Rate - Dense Gas Relation in the Nuclei of Nearby
  Galaxies

abstract:
  We investigate the relationship between the star formation rate (SFR) and
dense molecular gas mass in the nuclei of galaxies. To do this, we utilize the
observed 850 micron luminosity as a proxy for the infrared luminosity and SFR,
and correlate this with the observed CO (J=3-2) luminosity. We find tentative
evidence that the LIR-CO (J=3-2) index is similar to the Kennicutt-Schmidt (KS)
index (N ~ 1.5) in the central ~1.7 kpc of galaxies, and flattens to a roughly
linear index when including emission from the entire galaxy. This result may
imply that the volumetric Schmidt relation is the underlying driver behind the
observed SFR-dense gas correlations, and provides tentative confirmation for
recent numerical models. While the data exclude the possibility of a constant
LIR-CO (J=3-2) index for both galaxy nuclei and global measurements at the ~80%
confidence level, the considerable error bars cannot preclude alternative
interpretations.


title: Network Growth with Feedback

abstract:
  Existing models of network growth typically have one or two parameters or
strategies which are fixed for all times. We introduce a general framework
where feedback on the current state of a network is used to dynamically alter
the values of such parameters. A specific model is analyzed where limited
resources are shared amongst arriving nodes, all vying to connect close to the
root. We show that tunable feedback leads to growth of larger, more efficient
networks. Exact results show that linear scaling of resources with system size
yields crossover to a trivial condensed state, which can be considerably
delayed with sublinear scaling.


title: Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2

abstract:
  The ternary iron arsenide BaFe2As2 with the tetragonal ThCr2Si2-type
structure exhibits a spin density wave (SDW) anomaly at 140 K, very similar to
LaFeAsO, the parent compound of the iron arsenide superconductors. BaFe2As2 is
a poor Pauli-paramagnetic metal and undergoes a structural and magnetic phase
transition at 140 K, accompanied by strong anomalies in the specific heat,
electrical resistance and magnetic susceptibility. In the course of this
transition, the space group symmetry changes from tetragonal (I4/mmm) to
orthorhombic (Fmmm). 57Fe Moessbauer spectroscopy experiments show a single
signal at room temperature and full hyperfine field splitting below the phase
transition temperature (5.2 T at 77 K). Our results suggest that BaFe2As2 can
serve as a new parent compound for oxygen-free iron arsenide superconductors.


title: Scattering in flatland: Efficient representations via wave atoms

abstract:
  This paper presents a numerical compression strategy for the boundary
integral equation of acoustic scattering in two dimensions. These equations
have oscillatory kernels that we represent in a basis of wave atoms, and
compress by thresholding the small coefficients to zero. This phenomenon was
perhaps first observed in 1993 by Bradie, Coifman, and Grossman, in the context
of local Fourier bases \cite{BCG}. Their results have since then been extended
in various ways. The purpose of this paper is to bridge a theoretical gap and
prove that a well-chosen fixed expansion, the nonstandard wave atom form,
provides a compression of the acoustic single and double layer potentials with
wave number $k$ as $O(k)$-by-$O(k)$ matrices with $O(k^{1+1/\infty})$
nonnegligible entries, with a constant that depends on the relative $\ell_2$
accuracy $\eps$ in an acceptable way. The argument assumes smooth, separated,
and not necessarily convex scatterers in two dimensions. The essential features
of wave atoms that enable to write this result as a theorem is a sharp
time-frequency localization that wavelet packets do not obey, and a parabolic
scaling wavelength $\sim$ (essential diameter)${}^2$. Numerical experiments
support the estimate and show that this wave atom representation may be of
interest for applications where the same scattering problem needs to be solved
for many boundary conditions, for example, the computation of radar cross
sections.


title: Robust Joint Source-Channel Coding for Delay-Limited Applications

abstract:
  In this paper, we consider the problem of robust joint source-channel coding
over an additive white Gaussian noise channel. We propose a new scheme which
achieves the optimal slope of the signal-to-distortion (SDR) curve (unlike the
previously known coding schemes). Also, we propose a family of robust codes
which together maintain a bounded gap with the optimum SDR curve (in terms of
dB). To show the importance of this result, we drive some theoretical bounds on
the asymptotic performance of delay-limited hybrid digital-analog (HDA) coding
schemes. We show that, unlike the delay-unlimited case, for any family of
delay-limited HDA codes, the asymptotic performance loss is unbounded (in terms
of dB).


title: Hamiltonian Systems Inspired by the Schr\"odinger Equation

abstract:
  Described is n-level quantum system realized in the n-dimensional ''Hilbert''
space H with the scalar product G taken as a dynamical variable. The most
general Lagrangian for the wave function and G is considered. Equations of
motion and conservation laws are obtained. Special cases for the free evolution
of the wave function with fixed G and the pure dynamics of G are calculated.
The usual, first- and second-order modified Schr\"odinger equations are
obtained.


title:
Universal slow fall-off to the unique AdS infinity in
  Einstein-Gauss-Bonnet gravity

abstract:
  In this paper, the following two propositions are proven under the dominant
energy condition for the matter field in the higher-dimensional spherically
symmetric spacetime in Einstein-Gauss-Bonnet gravity in the presence of a
cosmological constant $\Lambda$. First, for $\Lambda\le 0$ and $\alpha \ge 0$
without a fine-tuning to give a unique anti-de Sitter vacuum, where $\alpha$ is
the Gauss-Bonnet coupling constant, vanishing generalized Misner-Sharp mass is
equivalent to the maximally symmetric spacetime. Under the fine-tuning, it is
equivalent to the vacuum class I spacetime. Second, under the fine-tuning with
$\alpha>0$, the asymptotically anti-de Sitter spacetime in the
higher-dimensional Henneaux-Teitelboim sense is only a special class of the
vacuum class I spacetime. The latter means the universal slow fall-off to the
unique anti-de Sitter infinity in the presence of physically reasonable matter.


title: Quantum Pareto Optimal Control

abstract:
  We describe algorithms, and experimental strategies, for the Pareto optimal
control problem of simultaneously driving an arbitrary number of quantum
observable expectation values to their respective extrema. Conventional quantum
optimal control strategies are less effective at sampling points on the Pareto
frontier of multiobservable control landscapes than they are at locating
optimal solutions to single observable control problems. The present algorithms
facilitate multiobservable optimization by following direct paths to the Pareto
front, and are capable of continuously tracing the front once it is found to
explore families of viable solutions. The numerical and experimental
methodologies introduced are also applicable to other problems that require the
simultaneous control of large numbers of observables, such as quantum optimal
mixed state preparation.


title:
Continuation of root functionals of a system of polynomial equations and
  the reduction of polynomials modulo its ideal

abstract:
  The notion of a root functional of polynomials is a generalization of the
notion of a root for a multiple root. A root functional is a linear functional
that is defined on a polynomial ring and annuls the ideal of a system of
polynomials. A bounded root functional is a functional that annuls d-th
component of the ideal in some filtration in this ideal. It was constructed the
operation of continuation of root functionals and the operation of reduction of
polynomials modulo the ideal on the basis of the extension operation for
bounded root functionals when the number of polynomials is equal to the number
of variables and the ideal of polynomials is 0-dimensional. The extension
operation has connection with the multivariate Bezoutian construction.


title: 1D-FFLO state in the absence of time-reversal symmetry breaking

abstract:
  A novel route to a one-dimensional Fulde-Ferrell-Larkin-Ovchinnikov (1D-FFLO)
state in the absence of broken time-reversal symmetry is proposed in this
paper. At present such a state may be encouraged in a clean AlAs quantum wire.
Using the AlAs quantum wire as an example it is shown using bosonization and
the renormalization group approach that the 1D-FFLO state can arise due to a
combination of Coulomb interactions and the unique bandstructure arrangement of
the AlAs quantum wire. The present theoretical proposal is very general and is
applicable to other systems with similar fermionic interaction terms.


title: Event Synchronization by Lightweight Message Passing

abstract:
  Concurrent ML's events and event combinators facilitate modular concurrent
programming with first-class synchronization abstractions. A standard
implementation of these abstractions relies on fairly complex manipulations of
first-class continuations in the underlying language. In this paper, we present
a lightweight implementation of these abstractions in Concurrent Haskell, a
language that already provides first-order message passing. At the heart of our
implementation is a new distributed synchronization protocol. In contrast with
several previous translations of event abstractions in concurrent languages, we
remain faithful to the standard semantics for events and event combinators; for
example, we retain the symmetry of $\mathtt{choose}$ for expressing selective
communication.


title: Multiple parton scattering in nuclei: gauge invariance

abstract:
  Within the framework of a generalized collinear factorization for multiple
parton scattering in nuclear medium, twist-4 contributions to DIS off a large
nucleus can be factorized as a convolution of hard parts and two-parton
correlation functions. The hard parts for the quark scattering in the
light-cone gauge correspond to interaction with a transverse (physical) gluon
in the target, while they are given by the second derivative of the cross
section with a longitudinal gluon in the covariant gauge. We provide a general
proof of the equivalence of the hard parts in the light-cone and covariant
gauge. We further demonstrate the equivalence in calculations of twist-4
contributions to semi-inclusive cross section of DIS in both lowest order and
next leading order. Calculations of the nuclear transverse momentum broadening
of the struck quark in the light-cone and covariant gauge are also discussed.


title: Non-minimal scalar fields in 2D de Sitter and dilaton black holes

abstract:
  We study non-minimal quantum fields in the gravitational field of
2-dimensional dilaton black holes and the de Sitter spacetime. We found that
the Green functions for non-minimal massless fields in a particular class of
dilaton black holes and in the de Sitter spacetime are almost identical. Using
this symmetry exact solutions are derived for quasinormal modes and bound
states in these background geometries. The problem of stability of dilaton
black holes is discussed.


title: Formation of optical vortices using coherent laser beam arrays

abstract:
  We present a novel proposal to generate an optical vortex beam by using the
coherent-superposition of multi-beams in a radial symmetrical configuration. In
terms of the generalized Huygens-Fresnel diffraction integral, we have derived
the general propagation expression for the coherent radial laser arrays. Based
on the derived formulae, we have analyzed the effects of the beamlet number,
the separation distance of the beamlets and the topological charge on the
intensity and phase distributions of the resulted beams. Our simulation results
show that optical vortices could be efficiently formed and generated due to the
interference and superposition effect of all the beamlets, during the
propagation process of the coherent radial laser arrays with the initial
well-organized phase distributions through the free space. In the focusing
system, the resulted beam near the focusing plane has the strong rotation
effect with the phase helicity.


title: A Search for New Physics with the BEACON Mission

abstract:
  The primary objective of the Beyond Einstein Advanced Coherent Optical
Network (BEACON) mission is a search for new physics beyond general relativity
by measuring the curvature of relativistic space-time around Earth. This
curvature is characterized by the Eddington parameter \gamma -- the most
fundamental relativistic gravity parameter and a direct measure for the
presence of new physical interactions. BEACON will achieve an accuracy of 1 x
10^{-9} in measuring the parameter \gamma, thereby going a factor of 30,000
beyond the present best result involving the Cassini spacecraft. Secondary
mission objectives include: (i) a direct measurement of the "frame-dragging"
and geodetic precessions in the Earth's rotational gravitomagnetic field, to
0.05% and 0.03% accuracy correspondingly, (ii) first measurement of gravity's
non-linear effects on light and corresponding 2nd order spatial metric's
effects to 0.01% accuracy. BEACON will lead to robust advances in tests of
fundamental physics -- this mission could discover a violation or extension of
general relativity and/or reveal the presence of an additional long range
interaction in physics. BEACON will provide crucial information to separate
modern scalar-tensor theories of gravity from general relativity, probe
possible ways for gravity quantization, and test modern theories of
cosmological evolution.


title: Magnetization and Spin Excitations of Non-Abelian Quantum Hall States

abstract:
  Significant insights into non-Abelian quantum Hall states were obtained from
studying special multi-particle interaction Hamiltonians, whose unique ground
states are the Moore-Read and Read-Rezayi states for the case of spinless
electrons. We generalize this approach to include the electronic spin-1/2
degree of freedom. We demonstrate that in the absence of Zeeman splitting the
ground states of such Hamiltonians have large degeneracies and very rich spin
structures. The spin structure of the ground states and low-energy excitations
can be understood based on an emergent SU(3) symmetry for the case
corresponding to the Moore-Read state. These states with different spin quantum
numbers represent non-Abelian quantum Hall states with different
magnetizations, whose quasi-hole properties are likely to be similar to those
of their spin polarized counterparts.


title: Positivity for toric vector bundles

abstract:
  We show that an equivariant vector bundle on a complete toric variety is nef
or ample if and only if its restriction to every invariant curve is nef or
ample, respectively. Furthermore, we show that nef toric vector bundles have a
nonvanishing global section at every point, and deduce that the underlying
vector bundle is trivial if and only if its restriction to every invariant
curve is trivial. We apply our methods and results to study, in particular, the
vector bundles M_L that arise as the kernel of the evaluation map on sections
of L, when L is an ample line bundle. We give examples of twists of such
bundles that are ample but not globally generated.


title:
Diagrammatic calculation of energy spectrum of quantum impurity in
  degenerate Bose-Einstein condensate

abstract:
  In this paper we considered a quantum particle moving through delute
Bose-Einstein condensate at zero temperature. In our formulation the impurity
particle interacts with the gas of uncoupled Bogoliubov's excitations. We
constructed the perturbation theory for the Green's function of the impurity
particle with respect to the impurity-condensate interaction employing the
coherent-state path integral approach. The perturbative expansion for the
Green's function is resumed into the expansion for its poles with the help of
the diagrammatic technique developed in this work. The dispersion relation for
the impurity clothed by condensate excitations is obtained and effective mass
is evaluated beyond the Golden rule approximation.


title:
Continuous Global Symmetries and Hyperweak Interactions in String
  Compactifications

abstract:
  We revisit general arguments for the absence of exact continuous global
symmetries in string compactifications and extend them to D-brane models. We
elucidate the various ways approximate continuous global symmetries arise in
the 4-dimensional effective action. In addition to two familiar methods -
axionic Peccei-Quinn symmetries and remnant global abelian symmetries from
Green-Schwarz gauge symmetry breaking - we identify new ways to generate
approximate continuous global symmetries. Two methods stand out, both of which
occur for local brane constructions within the LARGE volume scenario of moduli
stabilisation. The first is the generic existence of continuous non-abelian
global symmetries associated with local Calabi-Yau isometries. These symmetries
are exact in the non-compact limit and are spontaneously broken by the LARGE
volume, with breaking effects having phenomenologically interesting sizes \sim
0.01 for plausible choices for underlying parameters. Such approximate flavour
symmetries are phenomenologically attractive and may allow the fermion mass
hierarchies to be connected to the electroweak hierarchy via the large volume.
The second is the possible existence of new hyper-weak gauge interactions under
which Standard Model matter is charged, with \alpha_{HW} \sim 10^{-9}. Such
groups arise from branes wrapping bulk cycles and intersecting the local
(resolved) singularity on which the Standard Model is supported. We discuss
experimental bounds for these new gauge bosons and their interactions with the
Standard Model particles.


title: The perfect magnetic conductor (PMC) Casimir piston in d+1 dimensions

abstract:
  Perfect magnetic conductor (PMC) boundary conditions are dual to the more
familiar perfect electric conductor (PEC) conditions and can be viewed as the
electromagnetic analog of the boundary conditions in the bag model for hadrons
in QCD. Recent advances and requirements in communication technologies have
attracted great interest in PMC's and Casimir experiments involving structures
that approximate PMC's may be carried out in the not too distant future. In
this paper, we make a study of the zero-temperature PMC Casimir piston in $d+1$
dimensions. The PMC Casimir energy is explicitly evaluated by summing over
$p+1$-dimensional Dirichlet energies where p ranges from 2 to $d$ inclusively.
We derive two exact $d$-dimensional expressions for the Casimir force on the
piston and find that the force is negative (attractive) in all dimensions. Both
expressions are applied to the case of 2+1 and 3+1 dimensions. A spin-off from
our work is a contribution to the PEC literature: we obtain a useful
alternative expression for the PEC Casimir piston in 3+1 dimensions and also
evaluate the Casimir force per unit area on an infinite strip, a geometry of
experimental interest.

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


title:
System size and beam energy dependence of azimuthal anisotropy from
  PHENIX

abstract:
  We present azimuthal anisotropy measurements in Au+Au and Cu+Cu collisions at
$\sqrt{s_{NN}}$ = 62.4 and 200 GeV. Comparison between reaction plane and
cumulant $v_2$ measurements in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
show that non-flow contributions, originating mainly from jets, influence the
extracted $v_2$ for $p_T$ $\gtrsim$ 3.5 GeV/c. Number of constituent quark
(NCQ) scaling of $v_2$, when studied as a function of transverse kinetic energy
$KE_T$, is seen to hold for Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 and 200
GeV and for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV for $KE_{T}$
$\lesssim$ 1 GeV/c. Differential hexadecupole flow $v_4$ seems to exhibit
scaling with integral $v_2$ for centrality $\le$ 40% as has been observed for
differential $v_2$.


title: The evolutionary status of W Ursae Majoris-type systems

abstract:
  Well-determined physical parameters of 130 W UMa systems have been collected
from the literature. Based on these data, the evolutionary status and dynamical
evolution of W UMa systems are investigated. It is found that there is no
evolutionary difference between W- and A-type systems in $M-J$ diagram which is
consistent with the results derived from the analysis of observed spectral
type, $M-R$ and $M-L$ diagrams of W UMa systems. $M-R$ and $M-L$ diagrams of W-
and A-type systems indicate that a large amount of energy should be transferred
from the more massive to the less massive component so that they are not in
thermal equilibrium and undergo thermal relaxation oscillation (TRO).
Meanwhile, the distribution of angular momentum, together with the distribution
of mass ratio, suggests that the mass ratio of the observed W UMa systems is
decreased with the decrease of their total mass. This could be the result of
the dynamical evolution of W UMa systems which suffer angular momentum loss
(AML) and mass loss due to magnetic stellar wind (MSW). Consequently, the tidal
instability forces these systems towards the lower q values and finally to fast
rotating single stars.


title: The dynamical stability of W Ursae Majoris-type systems

abstract:
  Theoretical study indicates that a contact binary system would merge into a
rapidly rotating single star due to tidal instability when the spin angular
momentum of the system is more than a third of its orbital angular momentum.
Assuming that W UMa contact binary systems rigorously comply with the Roche
geometry and the dynamical stability limit is at a contact degree of about 70%,
we obtain that W UMa systems might suffer Darwin's instability when their mass
ratios are in a region of about 0.076--0.078 and merge into the fast-rotating
stars. This suggests that the W UMa systems with mass ratio $q\leq0.076$ can
not be observed. Meanwhile, we find that the observed W UMa systems with a mass
ratio of about 0.077, corresponding to a contact degree of about 86% would
suffer tidal instability and merge into the single fast-rotating stars. This
suggests that the dynamical stability limit for the observed W UMa systems is
higher than the theoretical value, implying that the observed systems have
probably suffered the loss of angular momentum due to gravitational wave
radiation (GR) or magnetic stellar wind (MSW).


title: Colossal electroresistance effect around room temperature in LuFe2O4

abstract:
  A colossal electroresistance effect is observed around room temperature in a
transition metal oxide LuFe2O4. The measurements of resistance under various
applied voltages as well as the highly nonlinear current-voltage
characteristics reveal that a small electric field is able to drive the
material from the insulating state to a metallic state. The threshold field at
which the insulating-metallic transition occurs, decreases exponentially with
increasing temperature. We interpret this transition as a consequence of the
breakdown of the charge-ordered state triggered by applied electric field,
which is supported by the dramatic dielectric response in a small electric
field. This colossal electroresistance effect as well as the high dielectric
tunability around room temperature in low applied fields makes LuFe2O4 a very
promising material for many applications.


title:
Boundary criticality at the Anderson transition between a metal and a
  quantum spin Hall insulator in two dimensions

abstract:
  Static disorder in a noninteracting gas of electrons confined to two
dimensions can drive a continuous quantum (Anderson) transition between a
metallic and an insulating state when time-reversal symmetry is preserved but
spin-rotation symmetry is broken. The critical exponent $\nu$ that
characterizes the diverging localization length and the bulk multifractal
scaling exponents that characterize the amplitudes of the critical wave
functions at the metal-insulator transition do not depend on the topological
nature of the insulating state, i.e., whether it is topologically trivial
(ordinary insulator) or nontrivial (a $Z_2$ insulator supporting a quantum spin
Hall effect). This is not true of the boundary multifractal scaling exponents
which we show (numerically) to depend on whether the insulating state is
topologically trivial or not.


title: The equation of state for scalar-tensor gravity

abstract:
  We show that the field equation of Brans-Dicke gravity and scalar-tensor
gravity can be derived as the equation of state of Rindler spacetime, where the
local thermodynamic equilibrium is maintained. Our derivation implies that the
effective energy can not feel the heat flow across the Rindler horizon.


title: Transport Control in Low-Dimensional Spin-1/2 Heisenberg Systems

abstract:
  We analyze transport of local magnetization and develop schemes to control
transport behavior in finite spin-1/2 Heisenberg chains and spin-1/2 Heisenberg
two-leg ladders at zero temperature. By adjusting parameters in the
Hamiltonians, these quantum systems may show both integrable and chaotic
limits. We provide examples of chaotic systems leading to diffusive and to
ballistic transport. In addition, methods of coherent quantum control to induce
a transition from diffusive to ballistic transport are proposed.


title:
Reinterpreting MOND: coupling of Einsteinian gravity and spin of cosmic
  neutrinos?

abstract:
  Several rare coincidences of scales in standard particle physics are needed
to explain (i) why neutrinos have mass, (ii) why the negative pressure of the
cosmological dark energy (DE) coincides with the positive pressure of random
motion of dark matter (DM) in bright galaxies, (iii) why Dark Matter in
galaxies seems to have a finite phase-space density, and to follow the
Tully-Fisher-Milgrom relation of galaxy rotation curves. The old idea of
self-interacting DM is given a new spin: we propose that the neutrino
spin-gravity coupling could lead to a cosmic neutrino dark fluid with a an
internal energy density varying as function of the local acceleration of the
neutrino fluid with respect the CMB background. We link the
Tully-Fisher-Milgrom relation of spiral galaxies (or MOND) with the
relativistic pressure of the neutrino dark fluid without modifying Einsteinian
gravity.


title:
On Constructing the Asymptotic Solutions for Phase Transitions in a
  Slender Cylinder Composed of a Compressible Hyperelastic Material with
  Clamped End Conditions

abstract:
  In this paper, we study phase transitions in a slender circular cylinder
composed of a compressible hyperelastic material with a non-convex strain
energy function. We aim to construct the asymptotic solutions based on an
axisymmetrical three-dimensional setting and use the results to describe the
key features (in particular, instability phenomena) observed in the experiments
by others. The difficult problem of the solution bifurcations of the governing
nonlinear partial differential equations (PDE's) is solved through a novel
approach. By using a methodology involving coupled series-asymptotic
expansions, we derive the normal form equation of the original complicated
system of nonlinear PDE's. By writing the normal form equation into a
first-order dynamical system and with a phase-plane analysis, we manage to
deduce the global bifurcation properties and to solve the boundary-value
problem analytically. The asymptotic solutions (including post-bifurcation
solutions) in terms of integrals are obtained. The engineering stress-strain
curve plotted from the asymptotic solutions can capture the key features of the
curve measured in a few experiments (e.g., the stress drop, the stress plateau,
and the small stress valley). It appears that the asymptotic solutions obtained
shed certain light on the instability phenomena associated with phase
transitions in a cylinder, in particular the role played by the radius-length
ratio. Also, an important feature of this work is that we consider the clamped
end conditions, which are more practical but rarely used in literature for
phase transition problems.


title:
Molecular Gas Distribution in Barred and Non-Barred Galaxies along the
  Hubble Sequence

abstract:
  We present results from a survey of 12CO(J=1-0) spectra obtained for the
central regions of 68 nearby galaxies at an angular resolution of 16 arcseconds
using the Nobeyama Radio Observatory 45m telescope, aimed at characterizing the
properties of star forming molecular gas. Combined with similar resolution
observations in the literature, the compiled sample set of 166 galaxies span a
wide range of galactic properties. NGC 4380, which was previously undetected in
CO, was detected.
  This initial paper of a series will focus on the data and the gaseous
properties of the samples, and particularly on the degree of central
concentration of molecular gas in a range of morphological types, from early
(S0/Sa) to late (Sd/Sm) galaxies with and without bars. The degree of molecular
central concentration in the central kiloparsec, compared to the central
several kiloparsecs of galaxies, is found to vary smoothly with Hubble type, so
that early type galaxies show larger central concentration. The comparison of
barred and non-barred galaxies within early and late type galaxies suggest that
difference in Hubble type, representing the effect of bulges, is the more
important factor in concentrating gas into the central regions than bars.


title: An NP-hardness Result on the Monoid Frobenius Problem

abstract:
  The following problem is NP-hard: given a regular expression $E$, decide if
$E^*$ is not co-finite.


title: Isospin analysis of D0 decay to three pions

abstract:
  The final state of the decay D0 --> pi+ pi- pi0 is analyzed in terms of
isospin eigenstates. It is shown that the final state is dominated by the
isospin-0 component. This suggests that isospin considerations may provide
insight into this and perhaps other $\Dz$-meson decay. We also discuss the
isospin nature of the nonresonant contribution in the decay, which can be
further understood by studying the decay D0 --> pi0 pi0 pi0.


title:
Photoproduction of Lambda(1405) and Sigma^{0}(1385) on the proton at
  E_\gamma = 1.5-2.4 GeV

abstract:
  Differential cross sections for $\gamma p \to K^+\Lambda(1405)$ and $\gamma p
\to K^+\Sigma^0(1385)$ reactions have been measured in the photon energy range
from 1.5 to 2.4 GeV and the angular range of $0.8<\cos(\Theta)<1.0$ for the
$K^+$ scattering angle in the center-of-mass system. This data is the first
measurement of the $\Lambda(1405)$ photoproduction cross section. The
lineshapes of \LamS measured in $\Sigma^+\pi^-$ and $\Sigma^-\pi^+$ decay modes
were different with each other, indicating a strong interference of the isospin
0 and 1 terms of the $\Sigma\pi$ scattering amplitudes. The ratios of \LamS
production to \SigS production were measured in two photon energy ranges: near
the production threshold ($1.5<E_\gamma<2.0$ GeV) and far from it ($2.0
<E_\gamma<2.4$ GeV). The observed ratio decreased in the higher photon energy
region, which may suggest different production mechanisms and internal
structures for these hyperon resonances.


title:
Transverse momentum broadening of heavy quark and gluon energy loss in
  Sakai-Sugimoto model

abstract:
  In this paper, we calculate the transverse momentum diffusion coefficient
kappa_T of heavy quark and gluon penetration length in the deconfinement phase
of Sakai-Sugimoto model, which is known as a holographic dual of large N_c QCD.
We find that for the heavy quark moving through the thermal plasma with a
constant velocity v<1, the transverse momentum diffusion coefficient kappa_T is
proportional to lamda*gamma^{{1/3}}*T^4/T_d, and the gluon penetration length
delta x is proportional to E^{{2/5}}. These results are different from those
calculated in N=4 super-Yang-Mills theory, where kappa_T is proportional to
lambda*gamma^{{1/2}}*T^3 and delta x is proportional to E^{{1/3}},
respectively. In the high energy limit, the difference between the two pairs of
results should be evident, so we expect that the future LHC experiments can
tell us which model is more closely related to the realistic strongly coupled
QCD at finite temperature.


title: Source Coding for a Simple Network with Receiver Side Information

abstract:
  We consider the problem of source coding with receiver side information for
the simple network proposed by R. Gray and A. Wyner in 1974. In this network, a
transmitter must reliably transport the output of two correlated information
sources to two receivers using three noiseless channels: a public channel which
connects the transmitter to both receivers, and two private channels which
connect the transmitter directly to each receiver. We extend Gray and Wyner's
original problem by permitting side information to be present at each receiver.
We derive inner and outer bounds for the achievable rate region and, for three
special cases, we show that the outer bound is tight.


title: The rule for a subdiffusive particle in an extremely diverse environment

abstract:
  The dynamics of a subdiffusive continuous time random walker in an
inhomogeneous environment is analyzed. In each microscopic jump, a random time
is drawn from a waiting time probability density function (WT-PDF) that decays
as a power law: phi(t;k)~k/(1+kt)^(1+beta), 0<beta<1. The parameter k, which is
the diffusion coefficient for the jump, is a random quantity also; in each
jump, it is drawn from a PDF, p(k)~1/k^gamma (0<gamma<1). We show that this
system exhibits a transition in the scaling law of its effective WT-PDF,
psi(t), which is obtained when averaging phi(t;k) with p(k). psi(t) decays as a
power law, psi(t)~1/t^(1+mu), and mu is given by two different formula. When
1-gamma> beta;, mu=beta, but when 1-gamma<beta, mu=1-gamma. The transition in
the scaling of psi(t) reflects the competition between two different mechanisms
for subdiffusion: subdiffusion due to the heavily tailed phi(t;k) for
microscopic jumps, and subdiffusion due to the collective effect of an
environment made of many slow local regions. These two different mechanisms for
subdiffusion are not additive, and compete each other. The reported transition
is dimension independent, and disappears when the power beta is also
distributed, in the range, 0<bate<1. Simulations exemplified the transition,
and implications are discussed.


title:
A microwave transmission-line network guiding electromagnetic fields
  through a dense array of metallic objects

abstract:
  We present measurements of a transmission-line network, designed for cloaking
applications in the microwave region. The network is used for channelling
microwave energy through an electrically dense array of metal objects, which is
basically impenetrable to the impinging electromagnetic radiation. With the
designed transmission-line network the waves emitted by a source placed in an
air-filled waveguide, are coupled into the network and guided through the array
of metallic objects. Our goal is to illustrate the simple manufacturing,
assembly, and the general feasibility of these types of cloaking devices.


title:
Realization of a certain class of semi-groups as value semi-groups of
  valuations

abstract:
  Given a well-ordered semi-group $\Gamma$ with a minimal system of generators
of ordinal type at most $\omega n$ and of rational rank $r$, which satisfies a
positivity and increasing condition, we construct a zero-dimensional valuation
centered on the ring of polynomials with $r$ variables such that the semi-group
of the values of the polynomial ring is equal to $\Gamma$. The construction
uses a generalization of Favre and Jonsson's version of MacLane's sequence of
key-polynomials.


title: Truth as value and duty: lessons of mathematics

abstract:
  I discuss some connotations of mathematical notion of "truth" in the context
of humanistic discourse


title: Refraction of Gluon jet in QGP

abstract:
  We introduce photon-like refraction for gluon jet in quark gluon plasma
created in high energy nucleus-nucleus collisions. A quark jet goes straightly
while a gluon jet is assumed to bend in the non-homogeneous medium. Combining
refraction and energy loss, we calculate the away-side dihadron $\Delta\phi$
distribution in central $Au+Au$ collisions at RHIC energy. The dihadrons from
quark-quark pair center around $\Delta\phi=\pi$, while the dihadrons from
quark-gluon and gluon-gluon pair are deflected from $\Delta\phi=\pi$. The
resulting distribution shows three peaks at intermediate $p_T$ since both
quark-quark and quark-gluon are important. However we only observe one center
peak at high $p_T$, where the quark-quark contribution dominates. These
observation qualitatively agrees with the experiment data.


title: Menger's Paths with Minimum Mergings

abstract:
  For an acyclic directed graph with multiple sources and multiple sinks, we
prove that one can choose the Merger's paths between the sources and the sinks
such that the number of mergings between these paths is upper bounded by a
constant depending only on the min-cuts between the sources and the sinks,
regardless of the size and topology of the graph. We also give bounds on the
minimum number of mergings between these paths, and discuss how it depends on
the min-cuts.


title: Sparse power-efficient topologies for wireless ad hoc sensor networks

abstract:
  We study the problem of power-efficient routing for multihop wireless ad hoc
sensor networks. The guiding insight of our work is that unlike an ad hoc
wireless network, a wireless ad hoc sensor network does not require full
connectivity among the nodes. As long as the sensing region is well covered by
connected nodes, the network can perform its task. We consider two kinds of
geometric random graphs as base interconnection structures: unit disk graphs
$\UDG(2,\lambda)$ and $k$-nearest-neighbor graphs $\NN(2,k)$ built on points
generated by a Poisson point process of density $\lambda$ in $\RR^2$. We
provide subgraph constructions for these two models $\US(2,\lambda)$ and
$\NS(2,k)$ and show that there are values $\lambda_s$ and $k_s$ above which
these constructions have the following good properties: (i) they are sparse;
(ii) they are power-efficient in the sense that the graph distance is no more
than a constant times the Euclidean distance between any pair of points; (iii)
they cover the space well; (iv) the subgraphs can be set up easily using local
information at each node. We also describe a simple local algorithm for routing
packets on these subgraphs. Our constructions also give new upper bounds for
the critical values of the parameters $\lambda$ and $k$ for the models
$\UDG(2,\lambda)$ and $\NN(2,k)$.


title: Symmetry justification of Lorenz' maximum simplification

abstract:
  In 1960 Edward Lorenz (1917-2008) published a pioneering work on the `maximum
simplification' of the barotropic vorticity equation. He derived a coupled
three-mode system and interpreted it as the minimum core of large-scale fluid
mechanics on a `finite but unbounded' domain. The model was obtained in a
heuristic way, without giving a rigorous justification for the chosen selection
of modes. In this paper, it is shown that one can legitimate Lorenz' choice by
using symmetry transformations of the spectral form of the vorticity equation.
The Lorenz three-mode model arises as the final step in a hierarchy of models
constructed via the component reduction by means of symmetries. In this sense,
the Lorenz model is indeed the `maximum simplification' of the vorticity
equation.

categories: physics.flu-dyn math-ph math.MP physics.ao-ph


title: Reduced fidelity susceptibility and its finite-size scaling behaviors

abstract:
  We derive a general formula of the reduced fidelity susceptibility when the
reduced density matrix is $2\times2$ block-diagonal. By using this result and
the continuous unitary transformations, we study finite-size scaling of the
reduced fidelity susceptibility in the Lipkin-Meshkov-Glick Model. It is found
that it can be used to characterize quantum phase transitions, implying that we
can extract information of quantum phase transitions only from the fidelity of
a subsystem, which is of practical meaning in experiments.


title:
Axial-vector transitions and strong decays of the baryon antidecuplet in
  the self-consistent SU(3) chiral quark-soliton model

abstract:
  We investigate the axial-vector transition constants of the baryon
antidecuplet to the octet and decuplet within the framework of the
self-consistent SU(3) chiral quark-soliton model. Taking into account
rotational 1/N_c and linear m_s corrections and using the symmetry-conserving
quantization, we calculate the axial-vector transition constants. It is found
that the leading-order contributions are generally almost canceled by the
rotational 1/N_c corrections. Thus, the m_s corrections turn out to be
essential contributions to the axial-vector constants. The decay width of the
Theta^+ to NK transition is determined to be Gamma(Theta -> NK)=0.71, MeV,
based on the result of the axial-vector transition constant g_A^* (Theta ->
NK)=0.05. In addition, other strong decays of the baryon antidecuplet are
investigated.


title:
Stabilization of unstable steady states by variable delay feedback
  control

abstract:
  We report on a dramatic improvement of the performance of the classical
time-delayed autosynchronization method (TDAS) to control unstable steady
states, by applying a time-varying delay in the TDAS control scheme in a form
of a deterministic or stochastic delay-modulation in a fixed interval around a
nominal value $T_0$. The successfulness of this variable delay feedback control
(VDFC) is illustrated by a numerical control simulation of the Lorenz and
R\"{o}ssler systems using three different types of time-delay modulations: a
sawtooth wave, a sine wave, and a uniform random distribution. We perform a
comparative analysis between the VDFC method and the standard TDAS method for a
sawtooth-wave modulation by analytically determining the domains of control for
the generic case of an unstable fixed point of focus type.


title: Eigenfunctions of Dirac operators at the threshold energies

abstract:
  We show that the eigenspaces of the Dirac operator $H=\alpha\cdot (D - A(x))
+ m \beta $ at the threshold energies $\pm m$ are coincide with the direct sum
of the zero space and the kernel of the Weyl-Dirac operator $\sigma\cdot (D -
A(x))$. Based on this result, we describe the asymptotic limits of the
eigenfunctions of the Dirac operator corresponding to these threshold energies.
Also, we discuss the set of vector potentials for which the kernels of $H\mp m$
are non-trivial, i.e. ${Ker}(H\mp m) \not = \{0 \}$.


title:
Quark-Antiquark Energy Density Function applied to Di-Gauge Boson
  Production at the LHC

abstract:
  In view of the start up of the 14 TeV pp Large Hadron Collider the quark
anti-quark reactions leading to the final states W^+W^-, W^+-Z^0 and Z^0Z^0 are
studied, in the frame workn of the Standard Model (SM), using helicity
amplitudes. The differential and total cross sections are first evaluated in
the parton-parton center of mass system. They are then transformed to their
expected behavior in pp collisions through the parton-parton Energy Density
Functions which are here derived from the known Parton Density Functions of the
proton. In particular the single and joint longitudinal polarizations of the
final state di-bosons are calculated. The effect on these reactions from the
presence of s-channel heavy vector bosons, like the W' and Z', are evaluated to
explore the possibility to utilize the gauge boson pair production as a probe
for these 'Beyond the SM' phenomena.


title: Second post-Newtonian approximation of Einstein-aether theory

abstract:
  In this paper, second post-Newtonian approximation of Einstein-aether theory
is obtained by Chandrasekhar's approach. Five parameterized post-Newtonian
parameters in first post-Newtonian approximation are presented after a time
transformation and they are identical with previous works, in which $\gamma=1$,
$\beta=1$ and two preferred-frame parameters remain. Meanwhile, in second
post-Newtonian approximation, a parameter, which represents third order
nonlinearity for gravity, is zero the same as in general relativity. For an
application for future deep space laser ranging missions, we reduce the metric
coefficients for light propagation in a case of $N$ point masses as a
simplified model of the solar system. The resulting light deflection angle in
second post-Newtonian approximation poses another constraint on the
Einstein-aether theory.


title:
Self-sustained magnetoelectric oscillations in magnetic resonant
  tunneling structures

abstract:
  The dynamic interplay of transport, electrostatic, and magnetic effects in
the resonant tunneling through ferromagnetic quantum wells is theoretically
investigated. It is shown that the carrier-mediated magnetic order in the
ferromagnetic region not only induces, but also takes part in intrinsic,
robust, and sustainable high-frequency current oscillations over a large window
of nominally steady bias voltages. This phenomenon could spawn a new class of
quantum electronic devices based on ferromagnetic semiconductors.


title: On the Discovery of the GZK Cut-off

abstract:
  The recent claim of the '5 sigma' observation of the Greisen and Zatzepin and
Kuzmin cut-off by the HiRes group based on their nine years data is a
significant step toward the eventual solution of the one of the most intriguing
questions which has been present in physics for more than forty years. However
the word 'significance' is used in the mentioned paper in the sense which is
not quite obvious. In the present paper we persuade that this claim is a little
premature.


title: On Multidimensional Pythagorean Numbers

abstract:
  To represent positive integers by regular patterns on a plane or in
three-dimensional space may be traced back to the Pythagoreans. The aim of the
present article is to explore the possibility of extending the representation
framework for integers to spaces with more than three dimensions. Thus, taking
up a definition of polygonal numbers given by Diophantus and by Nicomachus, and
generalizing the Pythagorean concept of gnomon, one is led through quite
elementary means to a single, unified definition of multidimensional number
formations henceforth called hypersolids.


title:
Nuclear enhancement and suppression of diffractive structure functions
  at high energies

abstract:
  We compute diffractive structure functions for both protons and nuclei in the
framework of Color Glass Condensate models with impact parameter dependence.
These models have previously been shown to provide good agreement with
inclusive F_2 measurements and exclusive vector meson measurements at HERA. For
nuclei, they provide good (parameter free) agreement with the inclusive F_2
data. We demonstrate good agreement of our computations with HERA measurements
on inclusive diffraction. We extend our analysis to nuclei and predict the
pattern of enhancement and suppression of the diffractive structures functions
that can be measured at an Electron Ion Collider. We discuss how the impact
parameter dependence crucially affects our analysis, in particular for large
invariant masses at fixed Q^2.


title: Extensional Uniformity for Boolean Circuits

abstract:
  Imposing an extensional uniformity condition on a non-uniform circuit
complexity class C means simply intersecting C with a uniform class L. By
contrast, the usual intensional uniformity conditions require that a
resource-bounded machine be able to exhibit the circuits in the circuit family
defining C. We say that (C,L) has the "Uniformity Duality Property" if the
extensionally uniform class C \cap L can be captured intensionally by means of
adding so-called "L-numerical predicates" to the first-order descriptive
complexity apparatus describing the connection language of the circuit family
defining C.
  This paper exhibits positive instances and negative instances of the
Uniformity Duality Property.


title:
Nuclear deformation and neutrinoless double-$\beta $ decay of
  $^{94,96}$Zr, $^{98,100}$Mo, $^{104}$Ru, $^{110}$Pd, $^{128,130}$Te and
  $^{150}$Nd nuclei in mass mechanism

abstract:
  The $(\beta ^{-}\beta ^{-})_{0\nu}$ decay of $^{94,96}$Zr, $^{98,100}$Mo,
$^{104}$Ru, $^{110}$Pd, $^{128,130}$Te and $^{150}$Nd isotopes for the
$0^{+}\to 0^{+}$ transition is studied in the Projected Hartree-Fock-Bogoliubov
framework. In our earlier work, the reliability of HFB intrinsic wave functions
participating in the $\beta ^{-}\beta ^{-}$ decay of the above mentioned nuclei
has been established by obtaining an overall agreement between the
theoretically calculated spectroscopic properties, namely yrast spectra,
reduced $B(E2$:$0^{+}\to 2^{+})$ transition probabilities, quadrupole moments
$Q(2^{+})$, gyromagnetic factors $g(2^{+})$ as well as half-lives
$T_{1/2}^{2\nu}$ for the $0^{+}\to 0^{+}$ transition and the available
experimental data. In the present work, we study the $(\beta ^{-}\beta
^{-})_{0\nu}$ decay for the $0^{+}\to 0^{+}$ transition in the mass mechanism
and extract limits on effective mass of light as well as heavy neutrinos from
the observed half-lives $T_{1/2}^{0\nu}(0^{+}\to 0^{+})$ using nuclear
transition matrix elements calculated with the same set of wave functions.
Further, the effect of deformation on the nuclear transition matrix elements
required to study the $(\beta ^{-}\beta ^{-})_{0\nu}$ decay in the mass
mechanism is investigated. It is noticed that the deformation effect on nuclear
transition matrix elements is of approximately same magnitude in $(\beta
^{-}\beta ^{-})_{2\nu}$ and $(\beta ^{-}\beta ^{-})_{0\nu}$ decay.


title: Semileptonic decays of $B_{s1}$, $B_{s2}^*$, $B_{s0}$ and $B_{s1}'$

abstract:
  Stimulated by recent observations of the excited bottom-strange mesons
$B_{s1}$ and $B_{s2}^*$, we calculate the semileptonic decays $B_{s0},
B_{s1}^{\prime}, B_{s1}, B_{s2}^*\to [D_s(1968), D_{s}^*(2112), D_{sJ}(2317),
D_{sJ}(2460)]\ell\bar{\nu}$, which is relevant for the exploration of the
potential of searching these semileptonic decays in experiment.


title:
Particle acceleration close to the supermassive black hole horizon: the
  case of M87

abstract:
  The radio galaxy M87 has recently been found to be a rapidly variable TeV
emitting source. We analyze the implications of the observed TeV
characteristics and show that it proves challenging to account for them within
conventional acceleration and emission models. We discuss a new pulsar-type
scenario for the origin of variable, very high energy (VHE) emission close to
the central supermassive black hole and show that magneto-centrifugally
accelerated electrons could efficiently Compton upscatter sub-mm ADAF disk
photons to the TeV regime, leading to VHE characteristics close to the observed
ones. This suggests, conversely, that VHE observations of highly under-luminous
AGNs could provide an important diagnostic tool for probing the conditions
prevalent in the inner accretion disk of these sources.


title: Twisted diagrams and homotopy sheaves

abstract:
  Twisted diagrams are "diagrams" with components in different categories.
Structure maps are defined using auxiliary data which consists of functors
relating the various categories to each other. Prime examples of the
construction are spectra (in the sense of homotopy theory) and quasi-coherent
sheaves on schemes. We develop the basic theory of twisted diagrams, and
establish various model structures (which are well-known in special cases). We
also introduce a notion of homotopy sheaves, a collection of local data which
is compatible up to weak equivalence, and study basic properties of such
objects. These objects occur in nature; for example, the notion of an
Omega-spectrum fits into this framework. The main purpose of the paper is to
provide a convenient reference for model structures on twisted diagrams, and
for the language of sheaves and homotopy sheaves as defined here.


title: Crossed product of groups. Applications

abstract:
  We survey the extensions of a group by a group using crossed products instead
of exact sequences of groups. The approach has various advantages, one of them
being that the crossed product is an universal object. Several new applications
are given, a general Schreier type theorem is proved and a few open problems
are left.


title:
Exact spectrum of the Lipkin-Meshkov-Glick model in the thermodynamic
  limit and finite-size corrections

abstract:
  The spectrum of the Lipkin-Meshkov-Glick model is exactly derived in the
thermodynamic limit by means of a spin coherent states formalism. In the first
step, a classical analysis allows one to distinguish between four distinct
regions in the parameter space according to the nature of the singularities
arising in the classical energy surface; these correspond to spectral critical
points. The eigenfunctions are then analyzed more precisely in terms of the
associated roots of the Majorana polynomial, leading to exact expressions for
the density of states in the thermodynamic limit. Finite-size effects are also
analyzed, leading in particular to logarithmic corrections near the
singularities occuring in the spectrum. Finally, we also compute expectation
values of the spin operators in a semi-classical analysis in order to
illustrate some subtle effects occuring in one region of the parameter space.


title: Landau levels and Riemann zeros

abstract:
  The number $N(E)$ of complex zeros of the Riemann zeta function with positive
imaginary part less than $E$ is the sum of a `smooth' function $\bar N(E)$ and
a `fluctuation'. Berry and Keating have shown that the asymptotic expansion of
$\bar N(E)$ counts states of positive energy less than $E$ in a `regularized'
semi-classical model with classical Hamiltonian $H=xp$. For a different
regularization, Connes has shown that it counts states `missing' from a
continuum. Here we show how the `absorption spectrum' model of Connes emerges
as the lowest Landau level limit of a specific quantum mechanical model for a
charged particle on a planar surface in an electric potential and uniform
magnetic field. We suggest a role for the higher Landau levels in the
fluctuation part of $N(E)$.

categories: math-ph cond-mat.mes-hall hep-th math.MP math.NT quant-ph


title:
Quasi one-dimensional magnetism driven by unusual orbital ordering in
  CuSb2O6

abstract:
  Essentially all undoped cuprates exhibit a quasi-planar, fourfold Cu-O
coordination responsible for the magnetically active antibonding
3d-(x^2-y^2)-like state. Here, we present an electronic structure study for
CuSb2O6 that reveals, in contrast, a half-filled 3d-(3z^2-r^2) orbital. This
hitherto unobserved ground state originates from a competition of in- and
out-of-plaquette orbitals where the strong Coulomb repulsion drives the
surprising and unique orbital ordering. This, in turn, gives rise to an
unexpected quasi one-dimensional magnetic behavior. Our results provide a
consistent explanation of recent thermodynamical and neutron diffraction
measurements.


title: Dynamics of thematic information flows

abstract:
  The studies of the dynamics of topical dataflow of new information in the
framework of a logistic model were suggested. The condition of topic balance,
when the number of publications on all topics is proportional to the
information space and time, was presented. General time dependence of the
publication intensity in the Internet, devoted to particular topics, was
observed; unlike an exponent model, it has a saturation area. Some limitations
of a logistic model were identified opening the way for further research.


title: Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

abstract:
  We discuss aspects of antihydrogen studies, that relate to particle physics
ideas and techniques, within the context of the ALPHA experiment at CERN's
Antiproton Decelerator facility. We review the fundamental physics motivations
for antihydrogen studies, and their potential physics reach. We argue that
initial spectroscopy measurements, once antihydrogen is trapped, could provide
competitive tests of CPT, possibly probing physics at the Planck Scale. We
discuss some of the particle detection techniques used in ALPHA. Preliminary
results from commissioning studies of a partial system of the ALPHA Si vertex
detector are presented, the results of which highlight the power of
annihilation vertex detection capability in antihydrogen studies.


title:
On the equi-normalizable deformations of singularities of complex plane
  curves

abstract:
  We study a specific class of deformations of curve singularities: the case
when the singular point splits to several ones, such that the total $\delta$
invariant is preserved. These are also known as equi-normalizable or
equi-generic deformations. We restrict primarily to the deformations of
singularities with smooth branches.
  A natural invariant of the singular type is introduced: the dual graph. It
imposes severe restrictions on the possible collisions/deformations. And allows
to prove some bounds on the variation of classical invariants in
equi-normalizable families.
  We consider in details deformations of ordinary multiple points, the
deformations of a singularity into the collections of ordinary multiple points
and deformations of the type $x^p+y^{pk}$ into the collections of $A_k$'s.


title:
Generalized Stirling permutations, families of increasing trees and urn
  models

abstract:
  Bona [2007+] studied the distribution of ascents, plateaux and descents in
the class of Stirling permutations, introduced by Gessel and Stanley [1978].
Recently, Janson [2008+] showed the connection between Stirling permutations
and plane recursive trees and proved a joint normal law for the parameters
considered by Bona. Here we will consider generalized Stirling permutations
extending the earlier results of Bona and Janson, and relate them with certain
families of generalized plane recursive trees, and also $(k+1)$-ary increasing
trees. We also give two different bijections between certain families of
increasing trees, which both give as a special case a bijection between ternary
increasing trees and plane recursive trees. In order to describe the
(asymptotic) behaviour of the parameters of interests, we study three
(generalized) Polya urn models using various methods.


title:
Peculiarities of the Correlation between Local and Global News
  Popularity of Electronic Mass Media

abstract:
  One of the approaches to the solution of the navigation problem in current
information flows is ranking the documents according to their popularity level.
The definition of local and global news popularity which is based on the number
of similar-in-content documents, published within local and global time
interval, was suggested. Mutual behavior of the documents of local and global
popularity levels was studied. The algorithm of detecting the documents which
received great popularity before new topics appeared was suggested.