title:
New Q matrices and their functional equations for the eight vertex model
  at elliptic roots of unity

abstract:
  The Q matrix invented by Baxter in 1972 to solve the eight vertex model at
roots of unity exists for all values of N, the number of sites in the chain,
but only for a subset of roots of unity. We show in this paper that a new Q
matrix, which has recently been introduced and is non zero only for N even,
exists for all roots of unity. In addition we consider the relations between
all of the known Q matrices of the eight vertex model and conjecture functional
equations for them.


title: Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores

abstract:
  We present a survey of the ortho-H2D+(1_{1,0}-1_{1,1}) line toward a sample
of 10 starless cores and 6 protostellar cores, carried out at the Caltech
Submillimeter Observatory. The high diagnostic power of this line is revealed
for the study of the chemistry, and the evolutionary and dynamical status of
low-mass dense cores. The line is detected in 7 starless cores and in 4
protostellar cores. N(ortho-H2D+) ranges between 2 and 40x10^{12} cm^{-2} in
starless cores and between 2 and 9x10^{12} cm^{-2} in protostellar cores. The
brightest lines are detected toward the densest and most centrally concentrated
starless cores, where the CO depletion factor and the deuterium fractionation
are also largest. The large scatter observed in plots of N(ortho-H2D+) vs. the
observed deuterium fractionation and vs. the CO depletion factor is likely to
be due to variations in the ortho-to-para (o/p) ratio of H2D+ from >0.5 for
T_{kin} < 10 K gas in pre-stellar cores to ~0.03 (consistent with T_{kin} ~15 K
for protostellar cores). The two Ophiuchus cores in our sample also require a
relatively low o/p ratio (~0.3). Other parameters, including the cosmic-ray
ionization rate, the CO depletion factor (or, more in general, the depletion
factor of neutral species), the volume density, the fraction of dust grains and
PAHs also largely affect the ortho-H2D+ abundance. The most deuterated and
H2D+-rich objects (L429, L1544, L694-2 and L183) are reproduced by chemical
models of centrally concentrated (central densties ~10^{6} cm^{-3}) cores with
chemical ages between 10^4 and 10^6 yr. Upper limits of the para-H3O+ (1_1-
-2_1+) and para-D2H+ (1_{1,0}-1_{0,1}) lines are also given. (Abridged)


title: Strategy abundance in 2x2 games for arbitrary mutation rates

abstract:
  We study evolutionary game dynamics in a well-mixed populations of finite
size, N. A well-mixed population means that any two individuals are equally
likely to interact. In particular we consider the average abundances of two
strategies, A and B, under mutation and selection. The game dynamical
interaction between the two strategies is given by the 2x2 payoff matrix
[(a,b), (c,d)]. It has previously been shown that A is more abundant than B, if
(N-2)a+Nb>Nc+(N-2)d. This result has been derived for particular stochastic
processes that operate either in the limit of asymptotically small mutation
rates or in the limit of weak selection. Here we show that this result holds in
fact for a wide class of stochastic birth-death processes for arbitrary
mutation rate and for any intensity of selection.


title: The Effect of Gas Physics on the Halo Mass Function

abstract:
  Cosmological tests based on cluster counts require accurate calibration of
the space density of massive halos, but most calibrations to date have ignored
complex gas physics associated with halo baryons. We explore the sensitivity of
the halo mass function to baryon physics using two pairs of gas-dynamic
simulations that are likely to bracket the true behavior. Each pair consists of
a baseline model involving only gravity and shock heating, and a refined
physics model aimed at reproducing the observed scaling of the hot,
intracluster gas phase. One pair consists of billion-particle re-simulations of
the original 500 Mpc/h Millennium Simulation of Springel et al. (2005), run
with the SPH code Gadget-2 and using a refined physics treatment approximated
by preheating (PH) at high redshift. The other pair are high-resolution
simulations from the adaptive-mesh refinement code ART, for which the refined
treatment includes cooling, star formation, and supernova feedback (CSF). We
find that, although the mass functions of the gravity-only (GO) treatments are
consistent with the recent calibration of Tinker et al. (2008), both pairs of
simulations with refined baryon physics show significant deviations. Relative
to the GO case, the masses of ~10^{14} Msun/h halos in the PH and CSF
treatments are shifted by averages of -15 \pm 1 percent and +12 \pm 5 percent,
respectively. These mass shifts cause ~ 30% deviations in number density
relative to the Tinker function, significantly larger than the 5% statistical
uncertainty of that calibration.


title:
Smooth and weak synthesis of the anti-diagonal in Fourier algebras of
  Lie groups

abstract:
  Let $G$ be a Lie group of dimension $n$, and let $A(G)$ be the Fourier
algebra of $G$. We show that the anti-diagonal
$\check{\Delta}_G=\{(g,g^{-1})\in G\times G \mid g\in G\}$ is both a set of
local smooth synthesis and a set of local weak synthesis of degree at most
$[\frac{n}{2}]+1$ for $A(G\times G)$. We achieve this by using the concept of
the cone property in \cite{ludwig-turowska}. For compact $G$, we give an
alternative approach to demonstrate the preceding results by applying the ideas
developed in \cite{forrest-samei-spronk}. We also present similar results for
sets of the form $HK$, where both $H$ and $K$ are subgroups of $G\times G\times
G\times G$ of diagonal forms. Our results very much depend on both the
geometric and the algebraic structure of these sets.


title:
Electromagnetically Interacting Massive Spin-2 Field: Intrinsic Cutoff
  and Pathologies in External Fields

abstract:
  By employing the Stueckelberg formalism, we argue that the theory of massive
spin-2 field coupled to electromagnetism in flat space must have an intrinsic,
model independent, finite UV cutoff. We show how the very existence of a cutoff
has connection to other pathologies of the system, such as superluminal
propagation. We comment on the generalization of the results to arbitrary spin,
and to gravitational interaction.


title: Late stage, non-equilibrium dynamics in the dipolar Ising model

abstract:
  Magnetic domain structures are a fascinating area of study with interest
deriving both from technological applications and fundamental scientific
questions. The nature of the striped magnetic phases observed in ultra-thin
films is one such intriguing system. The non-equilibrium dynamics of such
systems as they evolve toward equilibrium has only recently become an area of
interest and previous work on model systems showed evidence of complex, slow
dynamics with glass-like properties as the stripes order mesoscopically. To aid
in the characterization of the observed phases and the nature of the
transitions observed in model systems we have developed an efficient method for
identifying clusters or domains in the spin system, where the clusters are
based on the stripe orientation. Thus we are able to track the growth and decay
of such clusters of stripes in a Monte Carlo simulation and observe directly
the nature of the slow dynamics. We have applied this method to consider the
growth and decay of ordered domains after a quench from a saturated magnetic
state to temperatures near and well below the critical temperature in the two
dimensional dipolar Ising model. We discuss our method of identifying stripe
domains or clusters of stripes within this model and present the results of our
investigations.


title: Bayesian detection of unmodeled bursts of gravitational waves

abstract:
  The data analysis problem of coherently searching for unmodeled
gravitational-wave bursts in the data generated by a global network of
gravitational-wave observatories has been at the center of research for almost
two decades. As data from these detectors is starting to be analyzed, a renewed
interest in this problem has been sparked. A Bayesian approach to the problem
of coherently searching for gravitational wave bursts with a network of
ground-based interferometers is here presented. We demonstrate how to
systematically incorporate prior information on the burst signal and its source
into the analysis. This information may range from the very minimal, such as
best-guess durations, bandwidths, or polarization content, to complete prior
knowledge of the signal waveforms and the distribution of sources through
spacetime. We show that this comprehensive Bayesian formulation contains
several previously proposed detection statistics as special limiting cases, and
demonstrate that it outperforms them.


title: Eleven years of radio monitoring of the Type IIn supernova SN 1995N

abstract:
  We present radio observations of the optically bright Type IIn supernova SN
1995N. We observed the SN at radio wavelengths with the Very Large Array (VLA)
for 11 years. We also observed it at low radio frequencies with the Giant
Metrewave Radio Telescope (GMRT) at various epochs within $6.5-10$ years since
explosion. Although there are indications of an early optically thick phase,
most of the data are in the optically thin regime so it is difficult to
distinguish between synchrotron self absorption (SSA) and free-free absorption
(FFA) mechanisms. However, the information from other wavelengths indicates
that the FFA is the dominant absorption process. Model fits of radio emission
with the FFA give reasonable physical parameters. Making use of X-ray and
optical observations, we derive the physical conditions of the shocked ejecta
and the shocked CSM.


title: Water modeled as an intermediate element between carbon and silicon

abstract:
  Water and silicon are chemically dissimilar substances with common physical
properties. Their liquids display a temperature of maximum density, increased
diffusivity on compression, they form tetrahedral crystals and tetrahedral
amorphous phases. The common feature to water, silicon and carbon is the
formation of tetrahedrally coordinated units. We exploit these similarities to
develop a coarse-grained model of water (mW) that is essentially an atom with
tetrahedrality intermediate between carbon and silicon. mW mimics the
hydrogen-bonded structure of water through the introduction of a nonbond
angular dependent term that encourages tetrahedral configurations. The model
departs from the prevailing paradigm in water modeling: the use of long-ranged
forces (electrostatics) to produce short-ranged (hydrogen-bonded) structure. mW
has only short-range interactions yet it reproduces the energetics, density and
structure of liquid water, its anomalies and phase transitions with comparable
or better accuracy than the most popular atomistic models of water, at less
than 1% of the computational cost. We conclude that it is not the nature of the
interactions but the connectivity of the molecules that determines the
structural and thermodynamic behavior of water. The speedup in computing time
provided by mW makes it particularly useful for the study of slow processes in
deeply supercooled water, the mechanism of ice nucleation, wetting-drying
transitions, and as a realistic water model for coarse-grained simulations of
biomolecules and complex materials.


title: Direct evidence of a sub-stellar companion around CT Cha

abstract:
  In our ongoing search for close and faint companions around T Tauri stars, we
found a very faint (Ks=14.9mag, Ks_0=14.4mag) object, just ~2.67" northwest of
the Chamaeleon star-forming region member CT Cha corresponding to a projected
separation of ~440AU at 165+/-30 pc. We show that CT Cha A and this faint
object form a common proper motion pair from data of the VLT Adaptive Optics
(AO) instrument NACO taken in February 2006 and March 2007 and that the
companion is by >=4 sigma significance not a stationary background object. Our
AO integral field spectroscopy with SINFONI in J, and H+K bands yields a
temperature of 2600+/-250K for the companion and an optical extinction of
A_V=5.2+/-0.8mag, when compared to spectra calculated from Drift-Phoenix model
atmospheres. We demonstrate the validity of the model fits by comparison to
several other well-known young sub-stellar objects. Relative flux calibration
of the bands was achieved using photometry from the NACO imaging data. We
conclude that the CT Cha companion is a very low-mass member of Chamaeleon and
very likely a physical companion to CT Cha, as the probability for a by chance
alignment is <=0.01. Due to a prominent Pa-Beta emission in the J-band,
accretion is probably still ongoing onto the CT Cha companion. From temperature
and luminosity (log(Lbol/Lsun)= -2.68+/-0.21), we derive a radius of
R=2.20+0.81-0.60 R_Jup. We find a consistent mass of M=17+/-6 MJup for the CT
Cha companion from both its luminosity and temperature when placed on
evolutionary tracks. Hence, the CT Cha companion is most likely a wide brown
dwarf companion or possibly even a planetary mass object.


title:
Search for Large extra spatial dimensions in the dielectron and diphoton
  channels in $\bm{p\bar{p}}$ collisions at $\bm{\sqrt{s}=}$1.96 TeV

abstract:
  We report on a search for large extra spatial dimensions in the dielectron
and diphoton channels using a data sample of 1.05 \invfb of \ppb collisions at
a center-of-mass energy of 1.96 TeV collected by the D0 detector at the
Fermilab Tevatron Collider. The invariant mass spectrum of the data agrees well
with the prediction of the standard model. We find 95% C.L. lower limits on the
effective Planck scale between 2.1 and 1.3 TeV for 2 to 7 extra dimensions.


title: Gravitational Radiation from Plunging Orbits - Perturbative Study -

abstract:
  Numerical relativity has recently yielded a plethora of results about kicks
from spinning mergers which has, in turn, vastly increased our knowledge about
the spin interactions of black hole systems. In this work we use black hole
perturbation theory to calculate accurately the gravitational waves emanating
from the end of the plunging stage of an extreme mass ratio merger in order to
further understand this phenomenon. This study focuses primarily on spin
induced effects with emphasis on the maximally spinning limit and the
identification of possible causes of generic behavior.
  We find that gravitational waves emitted during the plunging phase exhibit
damped oscillatory behavior, corresponding to a coherent excitation of
quasi-normal modes by the test particle. This feature is universal in the sense
that the frequencies and damping time do not depend on the orbital parameters
of the plunging particle. Furthermore, the observed frequencies are distinct
from those associated with the usual free quasi-normal ringing. Our calculation
suggests that a maximum in radiated energy and momentum occurs at spin
parameters equal to $a/M=0.86$ and $a/M=0.81$, respectively for the plunge
stage of a polar orbit. The dependence of linear momentum emission on the angle
at which a polar orbit impacts the horizon is quantified. One of the advantages
of the perturbation approach adopted here is that insight into the actual
mechanism of radiation emission and its relationship to black hole ringing is
obtained by carefully identifying the dominant terms in the expansions used.


title:
Finiteness theorems for algebraic cycles of small codimension on quadric
  fibrations over curves

abstract:
  We obtain finiteness theorems for algebraic cycles of small codimension on
quadric fibrations X over curves over perfect fields k. For example, if k is
finitely generated over Q and the fibration has odd relative dimension at least
11, then CH^{i}(X) is finitely generated for i<=4.


title: Monopoles in CP(N-1) model via the state-operator correspondence

abstract:
  One of the earliest proposed phase transitions beyond the
Landau-Ginzburg-Wilson paradigm is the quantum critical point separating an
antiferromagnet and a valence-bond-solid on a square lattice. The low energy
description of this transition is believed to be given by the 2+1 dimensional
CP(1) model -- a theory of bosonic spinons coupled to an abelian gauge field.
Monopole defects of the gauge field play a prominent role in the physics of
this phase transition. In the present paper, we use the state-operator
correspondence of conformal field theory in conjunction with the 1/N expansion
to study monopole operators at the critical fixed point of the CP(N-1) model.
This elegant method reproduces the result for monopole scaling dimension
obtained through a direct calculation by Murthy and Sachdev. The technical
simplicity of our approach makes it the method of choice when dealing with
monopole operators in a conformal field theory.


title: Mechanics of Individual, Isolated Vortices in a Cuprate Superconductor

abstract:
  Superconductors often contain quantized microscopic whirlpools of electrons,
called vortices, that can be modeled as one-dimensional elastic objects.
Vortices are a diverse playground for condensed matter because of the interplay
between thermal fluctuations, vortex-vortex interactions, and the interaction
of the vortex core with the three-dimensional disorder landscape. While vortex
matter has been studied extensively, the static and dynamic properties of an
individual vortex have not. Here we employ magnetic force microscopy (MFM) to
image and manipulate individual vortices in detwinned, single crystal
YBa2Cu3O6.991 (YBCO), directly measuring the interaction of a moving vortex
with the local disorder potential. We find an unexpected and dramatic
enhancement of the response of a vortex to pulling when we wiggle it
transversely. In addition, we find enhanced vortex pinning anisotropy that
suggests clustering of oxygen vacancies in our sample and demonstrates the
power of MFM to probe vortex structure and microscopic defects that cause
pinning.


title: A Simple Framework to Typify Social Bibliographic Communities

abstract:
  Social Communities in bibliographic databases exist since many years,
researchers share common research interests, and work and publish together. A
social community may vary in type and size, being fully connected between
participating members or even more expressed by a consortium of small and
individual members who play individual roles in it. In this work, we focus on
social communities inside the bibliographic database DBLP and characterize
communities through a simple typifying description model. Generally, we
understand a publication as a transaction between the associated authors. The
idea therefore is to concern with directed associative relationships among
them, to decompose each pattern to its fundamental structure, and to describe
the communities by expressive attributes. Finally, we argue that the
decomposition supports the management of discovered structures towards the use
of adaptive-incremental mind-maps.


title:
Photoelectron spectra in strong-field ionization by a high frequency
  field

abstract:
  We analyze atomic photoelectron momentum distributions induced by bichromatic
and monochromatic laser fields within the strong field approximation (SFA),
separable Coulomb-Volkov approximation (SCVA), and ab initio treatment. We
focus on the high frequency regime -- the smallest frequency used is larger
than the ionization potential of the atom. We observe a remarkable agreement
between the ab initio and velocity gauge SFA results while the velocity gauge
SCVA fails to agree. Reasons of such a failure are discussed.


title:
Doping-Driven Collapse of the SDW Correlation Gap in
  SmFeAsO$_{1-x}$F$_{x}$

abstract:
  We report the Hall resistivity, $\rho_{xy}$ of polycrystalline
SmFeAsO$_{1-x}$F$_{x}$ for four different fluorine concentrations from the
onset of superconductivity through the collapse of the structural phase
transition. For the two more highly-doped samples, $\rho_{xy}$ is linear in
magnetic field up to 50 T with only weak temperature dependence, reminiscent of
a simple Fermi liquid. For the lightly-doped samples with $x<0.15$, we find a
low temperature regime characterized $\rho_{xy}(H)$ being both non-linear in
magnetic field and strongly temperature dependent even though the Hall angle is
small. The onset temperature for this non-linear regime is in the vicinity of
the structural phase (SPT)/spin density wave (SDW) transitions. The temperature
dependence of the Hall resistivity is consistent with a thermal activation of
carriers across an energy gap. The evolution of the energy gap with doping is
reported.


title: Tensor-product representations for string-net condensed states

abstract:
  We show that general string-net condensed states have a natural
representation in terms of tensor product states (TPS) . These TPS's are built
from local tensors. They can describe both states with short-range entanglement
(such as the symmetry breaking states) and states with long-range entanglement
(such as string-net condensed states with topological/quantum order). The
tensor product representation provides a kind of 'mean-field' description for
topologically ordered states and could be a powerful way to study quantum phase
transitions between such states. As an attempt in this direction, we show that
the constructed TPS's are fixed-points under a certain wave-function
renormalization group transformation for quantum states.


title:
Instability of higher dimensional charged black holes in the de-Sitter
  world

abstract:
  We have shown that higher dimensional Reissner-Nordstr\"om-de Sitter black
holes are gravitationally unstable for large values of the electric charge and
cosmological constant in $D \geq 7$ space-time dimensions. We have found the
shape of the slightly perturbed black hole at the threshold point of
instability. Why only $D=4, 5$ and 6 dimensional worlds are favorable as to the
black stability remains unknown.


title: Precise alpha_s from Tau Decays

abstract:
  An updated measurement of alpha_s(m_tau) from ALEPH tau hadronic spectral
functions is presented. We report a study of the perturbative prediction(s)
showing that the fixed-order perturbation theory manifests convergence or
principle problems not presented in the contour-improved calculation. Potential
systematic effects from quark-hadron duality violations are estimated to be
within the quoted systematic errors. The fit result is alpha_s(m_tau) = 0.344
+- 0.005 +- 0.007, where the first error is experimental and the second
theoretical. After evolution, the alpha_s(M_Z) determined from tau data is one
of the most precise to date, in agreement with the corresponding NNNLO value
derived from Z decays.


title: A Two-Dimensional Lattice Ion Trap for Quantum Simulation

abstract:
  Quantum simulations of spin systems could enable the solution of problems
which otherwise require infeasible classical resources. Such a simulation may
be implemented using a well-controlled system of effective spins, such as a
two-dimensional lattice of locally interacting ions. We propose here a layered
planar rf trap design that can be used to create arbitrary two-dimensional
lattices of ions. The design also leads naturally to ease of microfabrication.
As a first experimental demonstration, we confine strontium-88 ions in a
mm-scale lattice trap and verify numerical models of the trap by measuring the
motional frequencies. We also confine 440 nm diameter charged microspheres and
observe ion-ion repulsion between ions in neighboring lattice sites. Our
design, when scaled to smaller ion-ion distances, is appropriate for quantum
simulation schemes, e.g. that of Porras and Cirac (PRL 92 207901 (2004)). We
note, however, that in practical realizations of the trap, an increase in the
secular frequency with decreasing ion spacing may make a coupling rate that is
large relative to the decoherence rate in such a trap difficult to achieve.


title: Magic frequencies for cesium primary frequency standard

abstract:
  We consider microwave hyperfine transitions in the ground state of cesium and
rubidium atoms which are presently used as the primary and the secondary
frequency standards. The atoms are confined in an optical lattice generated by
a circularly polarized laser field. We demonstrate that applying an external
magnetic field with appropriately chosen direction may cancel dynamic Stark
frequency shift making the frequency of the clock transition insensitive to the
strengths of both the laser and the magnetic fields. This can be attained for
practically any laser frequency which is sufficiently distant from a resonance.


title: Recent Progress in the Understanding of the r-Process

abstract:
  A brief overview of the r-process is given with an emphasis on the
observational implications for this process. The conditions required for the
major production of the heavy r-process elements (r-elements) with mass numbers
A >130 are discussed based on a generic astrophysical model where matter
adiabatically expands from a hot and dense initial state. Nucleosynthesis in
the neutrino-driven winds from nascent neutron stars is discussed as a specific
example. Such winds readily produce the elements from Sr to Ag with A ~ 88 to
110 through charged-particle reactions in the alpha-process but appear
incapable of making the heavy r-elements. Observations of elemental abundances
in metal-poor stars have provided many valuable insights into the r-process.
They have demonstrated that the production of the heavy r-elements must be
associated with massive stars evolving on short timescales, provided evidence
strongly favoring core-collapse supernovae over neutron star mergers as the
major source for these elements, and shown that this source cannot produce any
significant amount of the low-A elements from Na to Ge including Fe. A
self-consistent astrophysical model of the r-process remains to be developed,
and it appears well worthwhile to carry out more comprehensive studies on the
evolution and explosion of the massive stars of ~ 8 to 11 M_sun that undergo
O-Ne-Mg core collapse and produce a very insignificant amount of the low-A
elements.


title:
Abundances in Metal-Poor Stars and Chemical Evolution of the Early
  Galaxy

abstract:
  We have attributed the elements from Sr through Ag in stars of low
metallicities ([Fe/H] < -1.5) to charged-particle reactions (CPR) in
neutrino-driven winds, which are associated with neutron star formation in
low-mass and normal supernovae (SNe) from progenitors of ~ 8 to 11 M_sun and ~
12 to 25 M_sun, respectively. Using this rule and attributing all Fe production
to normal SNe, we previously developed a phenomenological two-component model,
which predicts that [Sr/Fe] > -0.32 for all metal-poor stars. This is in direct
conflict with the high-resolution data now available, which show that there is
a great shortfall of Sr relative to Fe in many stars with [Fe/H] < -3. The same
conflict also exists for the CPR elements Y and Zr. We show that the data
require a stellar source leaving behind black holes and that hypernovae (HNe)
from progenitors of ~ 25 to 50 M_sun are the most plausible candidates. If we
expand our previous model to include three components (low-mass and normal SNe
and HNe), we find that essentially all of the data are very well described by
the new model. The HN yield pattern for the low-A elements from Na through Zn
(including Fe) is inferred from the stars deficient in Sr, Y, and Zr. We
estimate that HNe contributed ~ 24% of the bulk solar Fe inventory while normal
SNe contributed only ~ 9% (not the usually assumed ~ 33%). This implies a
greatly reduced role of normal SNe in the chemical evolution of the low-A
elements.


title: On "jamitons," self-sustained nonlinear traffic waves

abstract:
  "Phantom jams," traffic blockages that arise without apparent cause, have
long frustrated transportation scientists. Herein, we draw a novel homology
between phantom jams and a related class of self-sustained transonic waves,
namely detonations. Through this analogy, we describe the jam structure;
favorable agreement with reported measurements from congested highways is
observed. Complementary numerical simulations offer insights into the jams'
development. Our results identify conditions likely to result in a dangerous
concentration of vehicles and thereby lend guidance in traffic control and
roadway design.

categories: math.AP math-ph math.MP nlin.PS physics.soc-ph


title: Origin of the X-ray Emission in the Nuclei of FR Is

abstract:
  We investigate the X-ray origin in FRIs using the multi-waveband high
resolution data of eight FR I sources, which have very low Eddington ratios. We
fit their multi-waveband spectrum using a coupled accretion-jet model. We find
that X-ray emission in the source with the highest L_X (~1.8*10^-4 L_Edd) is
from the advection-dominated accretion flow (ADAF). Four sources with moderate
L_X(~several*10^-6 L_Edd) are complicated. The X-ray emission of one FR I is
from the jet, and the other three is from the sum of the jet and ADAF. The
X-ray emission in the three least luminous sources (L_X<1.0*10^-6L_Edd) is
dominated by the jet. These results roughly support the predictions of Yuan and
Cui(2005) where they predict that when the X-ray luminosity of the system is
below a critical value, the X-radiation will not be dominated by the emission
from the ADAF any longer, but by the jet. We also find that the accretion rates
in four sources must be higher than the Bondi rates, which implies that other
fuel supply (e.g., stellar winds) inside the Bondi radius should be important.


title: Hodge realizations of 1-motives and the derived Albanese

abstract:
  We prove that the embedding of the derived category of 1-motives into the
triangulated category of effective Voevodsky motives, as well as its left
adjoint functor $LAlb$, commute with the Hodge realization.


title:
Dynamical non-ergodic scaling in continuous finite-order quantum phase
  transitions

abstract:
  We investigate the emergence of universal dynamical scaling in quantum
critical spin systems adiabatically driven out of equilibrium, with emphasis on
quench dynamics which involves non-isolated critical points (i.e., critical
regions) and cannot be a priori described through standard scaling arguments
nor time-dependent perturbative approaches. Comparing to the case of an
isolated quantum critical point, we find that non-equilibrium scaling behavior
of a large class of physical observables may still be explained in terms of
equilibrium critical exponents. However, the latter are in general
non-trivially path-dependent, and detailed knowledge about the time-dependent
excitation process becomes essential. In particular, we show how multiple level
crossings within a gapless phase may completely suppress excitation depending
on the control path. Our results typify non-ergodic scaling in continuous
finite-order quantum phase transitions.


title:
Fermi Surface Evolution Across Multiple Charge Density Wave Transitions
  in ErTe3

abstract:
  The Fermi surface (FS) of ErTe3 is investigated using angle-resolved
photoemission spectroscopy (ARPES). Low temperature measurements reveal two
incommensurate charge density wave (CDW) gaps created by perpendicular FS
nesting vectors. A large Delta_1 = 175 meV gap arising from a CDW with c* -
q_CDW1 ~ 0.70(0) c* is in good agreement with the expected value. A second,
smaller Delta_2 = 50 meV gap is due to a second CDW with a* - q_CDW2 ~ 0.68(5)
a*. The temperature dependence of the FS, the two gaps and possible interaction
between the CDWs are examined.


title:
Second cohomology groups for algebraic groups and their Frobenius
  kernels

abstract:
  Let $G$ be a simple simply connected algebraic group scheme defined over an
algebraically closed field of characteristic $p > 0$. Let $T$ be a maximal
split torus in $G$, $B \supset T$ be a Borel subgroup of $G$ and $U$ its
unipotent radical. Let $F: G \rightarrow G$ be the Frobenius morphism. For $r
\geq 1$ define the Frobenius kernel, $G_r$, to be the kernel of $F$ iterated
with itself $r$ times. Define $U_r$ (respectively $B_r$) to be the kernel of
the Frobenius map restricted to $U$ (respectively $B$). Let $X(T)$ be the
integral weight lattice and $X(T)_+$ be the dominant integral weights.
  The computations of particular importance are $\h^2(U_1,k)$, $\h^2(B_r,\la)$
for $\la \in X(T)$, $\h^2(G_r,H^0(\la))$ for $\la \in X(T)_+$, and
$\h^2(B,\la)$ for $\la \in X(T)$. The above cohomology groups for the case when
the field has characteristic 2 one computed in this paper. These computations
complete the picture started by Bendel, Nakano, and Pillen for $p \geq 3$
\cite{BNP2}.


title:
Dominance of Sign Geometry and the Homogeneity of the Fundamental
  Topological Structure

abstract:
  We propose and support the possibility that the shape of topological density
2-point function in pure-glue QCD is crucially, and possibly entirely,
determined by the space-time folding (geometry) of the double-sheet
sign-coherent structure of Ref.[1], while the distribution of topological
density within individual sheets only determines the overall magnitude of the
correlator at finite physical distances. A specific manifestation of this,
discussed here, is that the shape of the correlation function (encoding e.g.
the masses of pseudoscalar glueballs) is reproduced upon the replacement q(x)
-> sgn(q(x)), i.e. by considering the double sheet of the same space-time
geometry but with constant magnitude of topological density. Combined with
previous results on the fundamental topological structure, this suggests that a
collective degree of freedom describing topological fluctuations of QCD vacuum
can be viewed as a global space-filling homogeneous double membrane. Selected
possibilities for practical uses of this are discussed.


title: Fundamental Constraints on Multicast Capacity Regions

abstract:
  Much of the existing work on the broadcast channel focuses only on the
sending of private messages. In this work we examine the scenario where the
sender also wishes to transmit common messages to subsets of receivers. For an
L user broadcast channel there are 2L - 1 subsets of receivers and
correspondingly 2L - 1 independent messages. The set of achievable rates for
this channel is a 2L - 1 dimensional region. There are fundamental constraints
on the geometry of this region. For example, observe that if the transmitter is
able to simultaneously send L rate-one private messages, error-free to all
receivers, then by sending the same information in each message, it must be
able to send a single rate-one common message, error-free to all receivers.
This swapping of private and common messages illustrates that for any broadcast
channel, the inclusion of a point R* in the achievable rate region implies the
achievability of a set of other points that are not merely component-wise less
than R*. We formerly define this set and characterize it for L = 2 and L = 3.
Whereas for L = 2 all the points in the set arise only from operations relating
to swapping private and common messages, for L = 3 a form of network coding is
required.


title: Weighing the spatial and temporal fluctuations of the dark universe

abstract:
  A generic prediction of the standard cosmology, based on general relativity
(GR), dark matter and the cosmological constant (and more generally, smooth
dark energy), is that, the two gravitational potentials describing the spatial
and temporal scalar perturbations of the universe are equivalent. Modifications
in GR or dark energy clustering in general violate this relation. Thus this
ratio serves as a smoking gun of the dark universe. We propose a method to
extract this ratio at various cosmological scales and redshifts from a set of
measurements, in a model independent way. The ratio measured by future surveys
has strong discriminating power for a variety of dark universe scenarios.


title:
Numerical Evolution of axisymmetric vacuum spacetimes: a code based on
  the Galerkin method

abstract:
  We present the first numerical code based on the Galerkin and Collocation
methods to integrate the field equations of the Bondi problem. The Galerkin
method like all spectral methods provide high accuracy with moderate
computational effort. Several numerical tests were performed to verify the
issues of convergence, stability and accuracy with promising results. This code
opens up several possibilities of applications in more general scenarios for
studying the evolution of spacetimes with gravitational waves.


title: Hanbury Brown-Twiss effect and thermal light ghost imaging

abstract:
  We show that the essential physics of the Hanbury Brown-Twiss (HBT) and the
thermal light ghost imaging experiments is the same, i.e., due to the intensity
fluctuations of the thermal light. However, in the ghost imaging experiments, a
large number of bits information needs to be treated together, whereas in the
HBT there is only one bit information required to be obtained. In the HBT
experiment far field is used for the purpose of easy detection, while in the
ghost image experiment near (or not-far) field is used for good quality image.


title:
Dark matter, dark energy and modern cosmology: the case for a Kuhnian
  paradigm shift

abstract:
  Several works in the last few years devoted to measure fundamental probes of
contemporary cosmology have suggested the existence of a delocalized dominant
component (the "dark energy"), in addition to the several-decade-old evidence
for "dark matter" other than ordinary baryons, both assuming the description of
gravity to be correct. Either we are faced to accept the ignorance of at least
95 % of the content of the universe or consider a deep change of the conceptual
framework to understand the data. Thus, the situation seems to be completely
favorable for a Kuhnian paradigm shift in either particle physics or cosmology.
We attempt to offer here a brief discussion of these issues from this
particular perspective, arguing that the situation qualifies as a textbook
Kuhnian anomaly, and offer a tentative identification of some of the actual
elements typically associated with the paradigm shift process "in the works" in
contemporary science.

categories: gr-qc astro-ph physics.hist-ph physics.pop-ph


title: Spectrum Sharing between Wireless Networks

abstract:
  We consider the problem of two wireless networks operating on the same
(presumably unlicensed) frequency band. Pairs within a given network cooperate
to schedule transmissions, but between networks there is competition for
spectrum. To make the problem tractable, we assume transmissions are scheduled
according to a random access protocol where each network chooses an access
probability for its users. A game between the two networks is defined. We
characterize the Nash Equilibrium behavior of the system. Three regimes are
identified; one in which both networks simultaneously schedule all
transmissions; one in which the denser network schedules all transmissions and
the sparser only schedules a fraction; and one in which both networks schedule
only a fraction of their transmissions. The regime of operation depends on the
pathloss exponent $\alpha$, the latter regime being desirable, but attainable
only for $\alpha>4$. This suggests that in certain environments, rival wireless
networks may end up naturally cooperating. To substantiate our analytical
results, we simulate a system where networks iteratively optimize their access
probabilities in a greedy manner. We also discuss a distributed scheduling
protocol that employs carrier sensing, and demonstrate via simulations, that
again a near cooperative equilibrium exists for sufficiently large $\alpha$.


title: The Impact of an Oxygen Dopant in an ideal Bi-2212 Crystal

abstract:
  Recent scanning tunneling microscopy studies have shown that local nanoscale
pairing inhomogenities are correlated with interstitial oxygen dopants in
Bi-2212. Combining electrostatic and cluster calculations, in this paper the
impact of a dopant on the local Madelung and charge transfer energies, magnetic
exchange J, Zhang-Rice mobility, and interactions with the lattice is
investigated. It is found that electrostatic modifications locally increases
the charge transfer energy and slightly suppresses J. It is further shown that
coupling to c-axis phonons is strongly modified near the dopant. The combined
effects of electrostatic modifications and coupling to the lattice yield
broadened spectral features, reduced charge gap energies, and a sizable local
increase of J. This implies a strong local interplay between
antiferromagnetism, polarons, and superconducting pairing.


title: Fixed Scale Approach to Equation of State in Lattice QCD

abstract:
  A new approach to study the equation of state in finite-temperature QCD is
proposed on the lattice. Unlike the conventional method in which the temporal
lattice size $N_t$ is fixed, the temperature $T$ is varied by changing $N_t$ at
fixed lattice scale. The pressure of the hot QCD plasma is calculated by the
integration of the trace anomaly with respect to $T$ at fixed lattice scale.
This "$T$-integral method" is tested in quenched QCD on isotropic and
anisotropic lattices and is shown to give reliable results especially at
intermediate and low temperatures.


title: The relative commutant of separable C*-algebras of real rank zero

abstract:
  We answer a question of E. Kirchberg (personal communication): does the
relative commutant of a separable C*-algebra in its ultrapower depend on the
choice of the ultrafilter?


title:
Interplay of local hydrogen-bonding and long-ranged dipolar forces in
  simulations of confined water

abstract:
  Spherical truncations of Coulomb interactions in standard models for water
permit efficient molecular simulations and can give remarkably accurate results
for the structure of the uniform liquid. However truncations are known to
produce significant errors in nonuniform systems, particularly for
electrostatic properties. Local molecular field (LMF) theory corrects such
truncations by use of an effective or restructured electrostatic potential that
accounts for effects of the remaining long-ranged interactions through a
density-weighted mean field average and satisfies a modified Poisson's equation
defined with a Gaussian-smoothed charge density. We apply LMF theory to three
simple molecular systems that exhibit different aspects of the failure of a
naive application of spherical truncations -- water confined between
hydrophobic walls, water confined between atomically-corrugated hydrophilic
walls, and water confined between hydrophobic walls with an applied electric
field. Spherical truncations of 1/r fail spectacularly for the final system in
particular, and LMF theory corrects the failings for all three. Further, LMF
theory provides a more intuitive way to understand the balance between local
hydrogen bonding and longer-ranged electrostatics in molecular simulations
involving water.


title: Local molecular field theory for the treatment of electrostatics

abstract:
  We examine in detail the theoretical underpinnings of previous successful
applications of local molecular field (LMF) theory to charged systems. LMF
theory generally accounts for the averaged effects of long-ranged components of
the intermolecular interactions by using an effective or restructured external
field. The derivation starts from the exact Yvon-Born-Green hierarchy and shows
that the approximation can be very accurate when the interactions averaged over
are slowly varying at characteristic nearest-neighbor distances. Application of
LMF theory to Coulomb interactions alone allows for great simplifications of
the governing equations. LMF theory then reduces to a single equation for a
restructured electrostatic potential that satisfies Poisson's equation defined
with a smoothed charge density. Because of this charge smoothing by a Gaussian
of width sigma, this equation may be solved more simply than the detailed
simulation geometry might suggest. Proper choice of the smoothing length sigma
plays a major role in ensuring the accuracy of this approximation. We examine
the results of a basic confinement of water between corrugated wall and justify
the simple LMF equation used in a previous publication. We further generalize
these results to confinements that include fixed charges in order to
demonstrate the broader impact of charge smoothing by sigma. The slowly-varying
part of the restructured electrostatic potential will be more symmetric than
the local details of confinements.


title: Astrophysical Tests of Lorentz and CPT Violation with Photons

abstract:
  A general framework for tests of Lorentz invariance with electromagnetic
waves is presented, allowing for operators of arbitrary mass dimension.
Signatures of Lorentz violations include vacuum birefringence, vacuum
dispersion, and anisotropies. Sensitive searches for violations using sources
such as active galaxies, gamma-ray bursts, and the cosmic microwave background
are discussed. Direction-dependent dispersion constraints are obtained on
operators of dimension 6 and 8 using gamma-ray bursts and the blazar Markarian
501. Stringent constraints on operators of dimension 3 are found using 5-year
data from the Wilkinson Microwave Anisotropy Probe. No evidence appears for
isotropic Lorentz violation, while some support at one sigma is found for
anisotropic violation.


title:
Exchange interaction and correlations radically change behaviour of a
  quantum particle in a classically forbidden region

abstract:
  Exchange interaction strongly influences the long-range behaviour of
localised electron orbitals and quantum tunneling amplitudes. It violates the
oscillation theorem (creates extra nodes) and produces a power-law decay
instead of the usual exponential decrease at large distances. For inner
orbitals inside molecules decay is $r^{-2}$, for macroscopic systems $\cos{(k_f
r)} r^{-\nu}$, where $k_f$ is the Fermi momentum and $\nu=3$ for 1D, $\nu=$3.5
for 2D and $\nu=$4 for 3D crystal. Correlation corrections do not change these
conclusions. Slow decay increases the exchange interaction between localized
spins and the under-barrier tunneling amplitude. The under-barrier transmission
coefficients in solids (e.g. for point contacts) become temperature-dependent.


title:
Spin-orbit interaction and spin relaxation in a two-dimensional electron
  gas

abstract:
  Using time-resolved Faraday rotation, the drift-induced spin-orbit Field of a
two-dimensional electron gas in an InGaAs quantum well is measured. Including
measurements of the electron mobility, the Dresselhaus and Rashba coefficients
are determined as a function of temperature between 10 and 80 K. By comparing
the relative size of these terms with a measured in-plane anisotropy of the
spin dephasing rate, the D'yakonv-Perel' contribution to spin dephasing is
estimated. The measured dephasing rate is significantly larger than this, which
can only partially be explained by an inhomogeneous g-factor.


title: Discovering hidden sectors with mono-photon Z' searches

abstract:
  In many theories of physics beyond the Standard Model, from extra dimensions
to Hidden Valleys and models of dark matter, Z' bosons mediate between Standard
Model particles and hidden sector states. We study the feasibility of observing
such hidden states through an invisibly decaying Z' at the LHC. We focus on the
process pp -> \gamma Z' -> \gamma X X*, where X is any neutral, (quasi-) stable
particle, whether a Standard Model (SM) neutrino or a new state. This
complements a previous study using pp -> Z Z' -> l+ l- X X*. Only the Z' mass
and two effective charges are needed to describe this process. If the Z' decays
invisibly only to Standard Model neutrinos, then these charges are predicted by
observation of the Z' through the Drell-Yan process, allowing discrimination
between Z' decays to SM neutrinos and invisible decays to new states. We
carefully discuss all backgrounds and systematic errors that affect this
search. We find that hidden sector decays of a 1 TeV Z' can be observed at 5
sigma significance with 50 fb^{-1} at the LHC. Observation of a 1.5 TeV state
requires super-LHC statistics of 1 ab^{-1}. Control of the systematic errors,
in particular the parton distribution function uncertainty of the dominant Z
\gamma background, is crucial to maximize the LHC search


title: Modal Analysis and Coupling in Metal-Insulator-Metal Waveguides

abstract:
  This paper shows how to analyze plasmonic metal-insulator-metal waveguides
using the full modal structure of these guides. The analysis applies to all
frequencies, particularly including the near infrared and visible spectrum, and
to a wide range of sizes, including nanometallic structures. We use the
approach here specifically to analyze waveguide junctions. We show that the
full modal structure of the metal-insulator-metal (MIM) waveguides--which
consists of real and complex discrete eigenvalue spectra, as well as the
continuous spectrum--forms a complete basis set. We provide the derivation of
these modes using the techniques developed for Sturm-Liouville and generalized
eigenvalue equations. We demonstrate the need to include all parts of the
spectrum to have a complete set of basis vectors to describe scattering within
MIM waveguides with the mode-matching technique. We numerically compare the
mode-matching formulation with finite-difference frequency-domain analysis and
find very good agreement between the two for modal scattering at symmetric MIM
waveguide junctions. We touch upon the similarities between the underlying
mathematical structure of the MIM waveguide and the PT symmetric quantum
mechanical pseudo-Hermitian Hamiltonians. The rich set of modes that the MIM
waveguide supports forms a canonical example against which other more
complicated geometries can be compared. Our work here encompasses the microwave
results, but extends also to waveguides with real metals even at infrared and
optical frequencies.


title: Correlation of Expert and Search Engine Rankings

abstract:
  In previous research it has been shown that link-based web page metrics can
be used to predict experts' assessment of quality. We are interested in a
related question: do expert rankings of real-world entities correlate with
search engine rankings of corresponding web resources? For example, each year
US News & World Report publishes a list of (among others) top 50 graduate
business schools. Does their expert ranking correlate with the search engine
ranking of the URLs of those business schools? To answer this question we
conducted 9 experiments using 8 expert rankings on a range of academic,
athletic, financial and popular culture topics. We compared the expert rankings
with the rankings in Google, Live Search (formerly MSN) and Yahoo (with list
lengths of 10, 25, and 50). In 57 search engine vs. expert comparisons, only 1
strong and 4 moderate correlations were statistically significant. In 42
inter-search engine comparisons, only 2 strong and 4 moderate correlations were
statistically significant. The correlations appeared to decrease with the size
of the lists: the 3 strong correlations were for lists of 10, the 8 moderate
correlations were for lists of 25, and no correlations were found for lists of
50.


title: Cosmology With Non-Minimally Coupled K-Field

abstract:
  We consider non-minimally coupled (with gravity) scalar field with
non-canonical kinetic energy. The form of the kinetic term is of
Dirac-Born-Infeld (DBI) form.We study the early evolution of the universe when
it is sourced only by the k-field, as well as late time evolution when both the
matter and k-field are present. For the k-field, we have considered constant
potential as well as potential inspired from Boundary String Field Theory
(B-SFT). We show that it is possible to have inflationary solution in early
time as well as late time accelerating phase. The solutions also exhibit
attractor property in a sense that it does not depend on the initial conditions
for a certain values of the parameters.


title: An AKARI Search for Intracluster Dust of Globular Clusters

abstract:
  We report the observations of 12 globular clusters with the AKARI/FIS. Our
goal is to search for emission from the cold dust within clusters. We detect
diffuse emissions toward NGC 6402 and 2808, but the IRAS 100-micron maps show
the presence of strong background radiation. They are likely emitted from the
galactic cirrus, while we cannot rule out the possible association of a bump of
emission with the cluster in the case of NGC 6402. We also detect 28 point-like
sources mainly in the WIDE-S images (90 micron). At least several of them are
not associated with the clusters but background galaxies based on some external
catalogs. We present the SEDs by combining the near-and-mid infrared data
obtained with the IRC if possible. The SEDs suggest that most of the point
sources are background galaxies. We find one candidate of the intracluster dust
which has no mid-infrared counterpart unlike the other point-like sources,
although some features such as its point-like appearance should be explained
before we conclude its intracluster origin. For most of the other clusters, we
have confirmed the lack of the intracluster dust. We evaluate upper limits of
the intracluster dust mass to be between 1.0E-05 and 1.0E-03 solar mass
depending on the dust temperature. The lifetime of the intracluster dust
inferred from the upper limits is shorter than 5 Myr (T=70K) or 50 Myr (35K).
Such short lifetime indicates some mechanism(s) are at work to remove the
intracluster dust. We also discuss its impact on the chemical evolution of
globular clusters.


title:
Aharonov-Bohm effect on AdS_2 and nonlinear supersymmetry of
  reflectionless Poschl-Teller system

abstract:
  We explain the origin and the nature of a special nonlinear supersymmetry of
a reflectionless Poschl-Teller system by the Aharonov-Bohm effect for a
nonrelativistic particle on the AdS_2. A key role in the supersymmetric
structure appearing after reduction by a compact generator of the AdS_2
isometry is shown to be played by the discrete symmetries related to the space
and time reflections in the ambient Minkowski space. We also observe that a
correspondence between the two quantum non-relativistic systems is somewhat of
the AdS/CFT holography nature.


title: Planet Migration through a Self-Gravitating Planetesimal Disk

abstract:
  We simulate planet migration caused by interactions between planets and a
planetesimal disk. We use an N-body integrator optimized for near-Keplerian
motion that runs in parallel on a video graphics card, and that computes all
pair-wise gravitational interactions. We find that the fraction of
planetesimals found in mean motion resonances is reduced and planetary
migration rates are on average about 50% slower when gravitational interactions
between the planetesimals are computed than when planetesimal self-gravity is
neglected. This is likely due to gravitational stirring of the planetesimal
disk that is not present when self-gravity is neglected that reduces their
capture efficiency because of the increased particle eccentricity dispersion.
We find that migration is more stochastic when the disk is self-gravitating or
comprised of more massive bodies. Previous studies have found that if the
planetesimal disk density is below a critical level, migration is "damped" and
the migration rate decays exponentially, otherwise it is "forced" and the
planet's migration rate could accelerate exponentially. Migration rates
measured from our undamped simulations suggest that the migration rate
saturates at a level proportional to disk density and subsequently is
approximately power law in form with time.


title:
Restoration of supersymmetry on the lattice: Two-dimensional
  $\mathcal{N}=(2,2)$ supersymmetric Yang-Mills theory

abstract:
  By numerically investigating the conservation law of the supercurrent, we
confirm the restoration of supersymmetry in Sugino's lattice formulation of the
two-dimensional $\mathcal{N}=(2,2)$ supersymmetric SU(2) Yang-Mills theory with
a scalar mass term. Subtlety in the case without the scalar mass term, that
appears to ruin perturbative power counting, is also pointed out.


title: Critical Behaviour of Structure Factors at a Quantum Phase Transition

abstract:
  We review the theoretical behaviour of the total and one-particle structure
factors at a quantum phase transition for temperature T=0. The predictions are
compared with exact or numerical results for the transverse Ising model, the
alternating Heisenberg chain, and the bilayer Heisenberg model. At the critical
wavevector, the results are generally in accord with theoretical expectations.
Away from the critical wavevector, however, different models display quite
different behaviours for the one-particle residues and structure factors.


title: Polynomial kernels for 3-leaf power graph modification problems

abstract:
  A graph G=(V,E) is a 3-leaf power iff there exists a tree T whose leaves are
V and such that (u,v) is an edge iff u and v are at distance at most 3 in T.
The 3-leaf power graph edge modification problems, i.e. edition (also known as
the closest 3-leaf power), completion and edge-deletion, are FTP when
parameterized by the size of the edge set modification. However polynomial
kernel was known for none of these three problems. For each of them, we provide
cubic kernels that can be computed in linear time for each of these problems.
We thereby answer an open problem first mentioned by Dom, Guo, Huffner and
Niedermeier (2005).


title: Lepton flavour violation in the supersymmetric type-II seesaw mechanism

abstract:
  We summarize the predictions for the radiative decays l_j->l_i \gamma within
the context of the supersymmetric type II seesaw mechanism considering
universal boundary conditions for the soft SUSY breaking terms. The dependence
on the low-energy neutrino parameters is discussed and the deviations from the
analytical results for large $\tan\beta$ analyzed.


title: Geometrical Rabi transitions between decoupled quantum states

abstract:
  A periodic perturbation such as a laser field cannot induce transitions
between two decoupled states for which the transition matrix element vanishes.
We show, however, that if in addition some system parameters are varied
adiabatically, such transitions become possible via adiabatic-change-induced
excitations to other states. We demonstrate that full amplitude transfer
between the two decoupled states can be achieved, and more significantly, the
evolution of the system only depends on its path in parameter space. Our
technique then provides a valuable means of studying nontrivial geometrical
dynamics via auxiliary states with large energy splittings.


title: A particle-hole model approach for hypernuclei

abstract:
  A particle-hole model is developed to describe the excitation spectrum of
single lambda hypernuclei and the possible presence of collective effects is
explored by making a comparison with the mean-field calculations. Results for
the spectra of 12C, 16O, 40Ca, 90Zr and 208Pb single lambda hypernuclei are
shown. The comparison with the available experimental data is satisfactory. We
find that collective phenomena are much less important in hypernuclei than in
ordinary nuclei.


title: Exact solutions for the Generalized Modified Degasperis-Procesi equation

abstract:
  this paper we show some new exact solutions for the generalized modified
Degasperis$-$Procesi equation (mDP equation)


title: Supersymmetric Wilson Loops in N=6 Super Chern-Simons-matter theory

abstract:
  We study supersymmetric Wilson loop operators in ABJM theory from both sides
of the AdS_4/CFT_3 correspondence. We first construct some supersymmetric
Wilson loops. The perturbative computations are performed in the field theory
side at the first two orders. A fundamental string solution ending on a
circular loop is also studied.


title: New solutions for the modified generalized Degasperis-Procesi equation

abstract:
  In this paper we show some new exact solutions for the generalized modified
Degasperis$-$Procesi equation (mDP equation)


title: About the seventh-order Kaup-Kupershmidt equation and its solutions

abstract:
  In this letter we obtain exact soliton and periodic solutions to the
seventh-order Kaup-Kupershmidt equation. We make use of the Cole-Hopf
transformation and two particular rational hyperbolic functions ansatze.


title: Free brace algebras are free prelie algebras

abstract:
  Let g be a free brace algebra. This structure implies that g is also a prelie
algebra and a Lie algebra. It is already known that g is a free Lie algebra. We
prove here that g is also a free prelie algebra, using a description of g with
the help of planar rooted trees, a permutative product, and anipulations on the
Poincar\'e-Hilbert series of g.


title: On a computer-aided approach to the computation of Abelian integrals

abstract:
  An accurate method to compute enclosures of Abelian integrals is developed.
This allows for an accurate description of the phase portraits of planar
polynomial systems that are perturbations of Hamiltonian systems. As an
example, it is applied to the study of bifurcations of limit cycles arising
from a cubic perturbation of an elliptic Hamiltonian of degree four.


title: A new approach to the family of singularities $Re(x+iy)^m$

abstract:
  Assume that $m\ge 2$ and let $l$ be a nonnegative integer with $l\ge m-4$. We
give an alternative proof of the fact that any smooth function defined locally
around $(0,0)\in \mathbb{R}^2$ with the Taylor power series at $(0,0)$
beginning with $$Re(x+iy)^m+0+...+0$$ ($l$ zeros) is diffeomorphically
equivalent to $Re(x+iy)^m$ at $(0,0)$. For $m\ge 5$ and $C\ne 0$ we show that
the function $$Re(x+iy)^m+C(x^2+y^2)^{m-2}$$ is not diffeomorphically
equivalent to $Re(x+iy)^m$ at $(0,0)$.


title: Stirring Strongly Coupled Plasma

abstract:
  We determine the energy it takes to move a test quark along a circle of
radius L with angular frequency w through the strongly coupled plasma of N=4
supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w
the energy deposited by stirring the plasma in this way is governed either by
the drag force acting on a test quark moving through the plasma in a straight
line with speed v=Lw or by the energy radiated by a quark in circular motion in
the absence of any plasma, whichever is larger. There is a continuous crossover
from the drag-dominated regime to the radiation-dominated regime. In the
crossover regime we find evidence for significant destructive interference
between energy loss due to drag and that due to radiation as if in vacuum. The
rotating quark thus serves as a model system in which the relative strength of,
and interplay between, two different mechanisms of parton energy loss is
accessible via a controlled classical gravity calculation. We close by
speculating on the implications of our results for a quark that is moving
through the plasma in a straight line while decelerating, although in this case
the classical calculation breaks down at the same value of the deceleration at
which the radiation-dominated regime sets in.


title:
Exact solutions for the general fifth order KdV equation by the extended
  tanh method

abstract:
  In this paper we show some exact solutions for the general fifth order KdV
equation. These solutions are obtained by the extended tanh method.


title:
Dynamics of protein-protein encounter: a Langevin equation approach with
  reaction patches

abstract:
  We study the formation of protein-protein encounter complexes with a Langevin
equation approach that considers direct, steric and thermal forces. As three
model systems with distinctly different properties we consider the pairs
barnase:barstar, cytochrome c:cytochrome c peroxidase and p53:MDM2. In each
case, proteins are modeled either as spherical particles, as dipolar spheres or
as collection of several small beads with one dipole. Spherical reaction
patches are placed on the model proteins according to the known experimental
structures of the protein complexes. In the computer simulations, concentration
is varied by changing box size. Encounter is defined as overlap of the reaction
patches and the corresponding first passage times are recorded together with
the number of unsuccessful contacts before encounter. We find that encounter
frequency scales linearly with protein concentration, thus proving that our
microscopic model results in a well-defined macroscopic encounter rate. The
number of unsuccessful contacts before encounter decreases with increasing
encounter rate and ranges from 20-9000. For all three models, encounter rates
are obtained within one order of magnitude of the experimentally measured
association rates. Electrostatic steering enhances association up to 50-fold.
If diffusional encounter is dominant (p53:MDM2) or similarly important as
electrostatic steering (barnase:barstar), then encounter rate decreases with
decreasing patch radius. More detailed modeling of protein shapes decreases
encounter rates by 5-95 percent. Our study shows how generic principles of
protein-protein association are modulated by molecular features of the systems
under consideration. Moreover it allows us to assess different coarse-graining
strategies for the future modelling of the dynamics of large protein complexes.


title:
Basic properties of nonsmooth Hormander's vector fields and Poincare's
  inequality

abstract:
  We consider a family of vector fields defined in some bounded domain of R^p,
and we assume that they satisfy Hormander's rank condition of some step r, and
that their coefficients have r-1 continuous derivatives. We extend to this
nonsmooth context some results which are well-known for smooth Hormander's
vector fields, namely: some basic properties of the distance induced by the
vector fields, the doubling condition, Chow's connectivity theorem, and, under
the stronger assumption that the coefficients belong to C^{r-1,1}, Poincare's
inequality. By known results, these facts also imply a Sobolev embedding. All
these tools allow to draw some consequences about second order differential
operators modeled on these nonsmooth Hormander's vector fields.


title:
Sharp change over from compound nuclear fission to shape dependent quasi
  fission

abstract:
  Fission fragment mass distribution has been measured from the decay of
$^{246}$Bk nucleus populating via two entrance channels with slight difference
in mass asymmetries but belonging on either side of the Businaro Gallone mass
asymmetry parameter. Both the target nuclei were deformed. Near the Coulomb
barrier, at similar excitation energies the width of the fission fragment mass
distribution was found to be drastically different for the $^{14}$N +
$^{232}$Th reaction compared to the $^{11}$B + $^{235}$U reaction. The entrance
channel mass asymmetry was found to affect the fusion process sharply.


title: Time-dependent version of cryptohermitian quantum theory

abstract:
  For many quantum models an apparent non-Hermiticity of observables
corresponds to their hidden Hermiticity in another, physical Hilbert space. For
these models we show that the existence of observables which are manifestly
time-dependent may require the use of a manifestly time-dependent
representation of the physical Hilbert space of states.


title:
The Hilbert space of 3d gravity: quantum group symmetries and
  observables

abstract:
  We relate three-dimensional loop quantum gravity to the combinatorial
quantisation formalism based on the Chern-Simons formulation for
three-dimensional Lorentzian and Euclidean gravity with vanishing cosmological
constant. We compare the construction of the kinematical Hilbert space and the
implementation of the constraints. This leads to an explicit and very
interesting relation between the associated operators in the two approaches and
sheds light on their physical interpretation. We demonstrate that the quantum
group symmetries arising in the combinatorial formalism, the quantum double of
the three-dimensional Lorentz and rotation group, are also present in the loop
formalism. We derive explicit expressions for the action of these quantum
groups on the space of cylindrical functions associated with graphs. This
establishes a direct link between the two quantisation approaches and clarifies
the role of quantum group symmetries in three-dimensional gravity.


title:
Comparison of coronagraphs for high contrast imaging in the context of
  Extremely Large Telescopes

abstract:
  We compare coronagraph concepts and investigate their behavior and
suitability for planet finder projects with Extremely Large Telescopes (ELTs,
30-42 meters class telescopes). For this task, we analyze the impact of major
error sources that occur in a coronagraphic telescope (central obscuration,
secondary support, low-order segment aberrations, segment reflectivity
variations, pointing errors) for phase, amplitude and interferometric type
coronagraphs. This analysis is performed at two different levels of the
detection process: under residual phase left uncorrected by an eXtreme Adaptive
Optics system (XAO) for a large range of Strehl ratio and after a general and
simple model of speckle calibration, assuming common phase aberrations between
the XAO and the coronagraph (static phase aberrations of the instrument) and
non-common phase aberrations downstream of the coronagraph (differential
aberrations provided by the calibration unit). We derive critical parameters
that each concept will have to cope with by order of importance. We evidence
three coronagraph categories as function of the accessible angular separation
and proposed optimal one in each case. Most of the time amplitude concepts
appear more favorable and specifically, the Apodized Pupil Lyot Coronagraph
gathers the adequate characteristics to be a baseline design for ELTs.


title:
Quantum phase transition in space in a ferromagnetic spin-1
  Bose-Einstein condensate

abstract:
  A quantum phase transition between the symmetric (polar) phase and the phase
with broken symmetry can be induced in a ferromagnetic spin-1 Bose-Einstein
condensate in space (rather than in time). We consider such a phase transition
and show that the transition region in the vicinity of the critical point
exhibits scalings that reflect a compromise between the rate at which the
transition is imposed (i.e., the gradient of the control parameter) and the
scaling of the divergent healing length in the critical region. Our results
suggest a method for the direct measurement of the scaling exponent nu.


title:
Optimal Time to Sell a Stock in Black-Scholes Model: Comment on "Thou
  shall buy and hold", by A. Shiryaev, Z. Xu and X.Y. Zhou

abstract:
  We reconsider the problem of optimal time to sell a stock studied recently by
Shiryaev, Xu and Zhou using path integral methods. This method allows us to
confirm the results obtained by these authors and extend them to a parameter
region inaccessible to the method used by Shiryaev et. al. We also obtain the
full distribution of the time t_m at which the maximum of the price is reached
for arbitrary values of the drift.


title: An analogue of the Szemeredi Regularity Lemma for bounded degree graphs

abstract:
  We show that a sufficiently large graph of bounded degree can be decomposed
into quasi-homogeneous pieces. The result can be viewed as a "finitarization"
of the classical Farrell-Varadarajan Ergodic Decomposition Theorem.


title: La droite de Berkovich sur Z

abstract:
  We study here the Berkovich line over the ring of integers of a number field.
It is a natural object which contains complex and non-Archimedean analytic
spaces associated to each place. We prove that this line satisfies good
topological and algebraic properties and exhibit a few examples of Stein spaces
that lie in it. We derive applications to the study of convergent arithmetic
power series: choice of zeroes and poles, noetherianity of global rings and
inverse Galois problem. Typical examples of such power series are given by
analytic functions on the open complex unit disk whose Taylor development in 0
has integer coefficients.


title:
Polaron Coherence as Origin of the Pseudogap Phase in High Temperature
  Superconducting Cuprates

abstract:
  Within a two component approach to high Tc copper oxides including polaronic
couplings, we identify the pseudogap phase as the onset of polaron ordering.
This ordering persists in the superconducting phase. A huge isotope effect on
the pseudogap onset temperature is predicted and in agreement with experimental
data. The anomalous temperature dependence of the mean square copper oxygen ion
displacement observed above, at and below Tc stems from an s-wave
superconducting component of the order parameter, whereas a pure d-wave order
parameter alone can be excluded.


title: Complexity and white-dwarf structure

abstract:
  From the low-mass non-relativistic case to the relativistic limit, the
density profile of a white dwarf is used to evaluate the complexity measure.
Similarly to the recently reported atomic case where, by averaging shell
effects, complexity grows with the atomic number, here complexity grows as a
function of the star mass reaching a maximum finite value in the Chandrasekhar
limit.


title: A Simple Model for Solar Isorotational Contours

abstract:
  The solar convective zone, or SCZ, is nearly adiabatic and marginally
convectively unstable. But the SCZ is also in a state of differential rotation,
and its dynamical stability properties are those of a weakly magnetized gas.
This renders it far more prone to rapidly growing rotational baroclinic
instabilities than a hydrodynamical system would be. These instabilities should
be treated on the same footing as convective instabilites. If isentropic and
isorotational surfaces coincide in the SCZ, the gas is marginally (un)stable to
{\em both} convective and rotational disturbances. This is a plausible
resolution for the instabilities associated with these more general rotating
convective systems. This motivates an analysis of the thermal wind equation in
which isentropes and isorotational surfaces are identical. The characteristics
of this partial differential equation correspond to isorotation contours, and
their form may be deduced even without precise knowledge of how the entropy and
rotation are functionally related. Although the exact solution of the global
SCZ problem in principle requires this knowledge, even the simplest models
produce striking results in broad agreement with helioseismology data. This
includes horizontal (i.e. quasi-spherical) isorotational contours at the poles,
axial contours at the equator, and approximately radial contours at
midlatitudes. The theory does not apply directly to the tachocline, where a
simple thermal wind balance is not expected to be valid. The work presented
here is subject to tests of self-consistency, among them the prediction that
there should be good agreement between isentropes and isorotational contours in
sufficiently well-resolved large scale numerical MHD simulations.


title:
On an algorithm that generates an interesting maximal set P(n) of the
  naturals for any n greater than or equal to 2

abstract:
  The paper considers the problem of finding the largest possible set P(n), a
subset of the set N of the natural numbers, with the property that a number is
in P(n) if and only if it is a sum of n distinct naturals all in P(n) or none
in P(n). Here largest is in the set theoretic sense and n is greater than or
equal to 2. We call P(n) a maximal set obeying this property. For small n say 2
or 3, it is possible to develop P(n) intuitively but we strongly felt the
necessity of an algorithm for any n greater than or equal to 2. Now P(n) shall
invariably be a infinite set so we define another set Q(n) such that
Q(n)=N-P(n), prove that Q(n) is finite and, since P(n) is automatically known
if Q(n) is known, design an algorithm of worst case O(1) complexity which
generates Q(n).


title: Nonperturbative infrared fixed point in sextet QCD

abstract:
  The SU(3) gauge theory with fermions in the sextet representation is one of
several theories of interest for technicolor models. We have carried out a
Schrodinger functional (SF) calculation for the lattice theory with two flavors
of Wilson fermions. We find that the discrete beta function changes sign when
the SF renormalized coupling is in the neighborhood of g^2 = 2.0, showing a
breakdown of the perturbative picture even though the coupling is weak. The
most straightforward interpretation is an infrared-stable fixed point.


title: CP parameters of the B systems from Tevatron

abstract:
  Recent results on CP parameters of the B systems obtained by the CDF and D0
collaborations using the data samples collected at the Tevatron Collider in the
period 2002 - 2007 were presented at the QCD 2008 conference (Montpellier,
France). These results include measurements of the mixing phase, decay width
difference, and CP violation parameters in the Bs and Bu decays.


title:
Uncovering the hidden order in URu2Si2: Identification of Fermi surface
  instability and gapping

abstract:
  Spontaneous, collective ordering of electronic degrees of freedom leads to
second-order phase transitions that are characterized by an order parameter.
The notion "hidden order" (HO) has recently been used for a variety of
materials where a clear phase transition occurs to a phase without a known
order parameter. The prototype example is the heavy-fermion compound URu2Si2
where a mysterious HO transition occurs at 17.5K. For more than twenty years
this system has been studied theoretically and experimentally without a firm
grasp of the underlying physics. Using state-of-the-art density-functional
theory calculations, we provide here a microscopic explanation for the HO. We
identify the Fermi surface "hot spots" where degeneracy induces a Fermi surface
instability and quantify how symmetry breaking lifts the degeneracy, causing a
surprisingly large Fermi surface gapping. As mechanism for the HO we propose
spontaneous symmetry breaking through collective antiferromagnetic moment
excitations.


title:
Canonical Formalism for a 2n-Dimensional Model with Topological Mass
  Generation

abstract:
  The four-dimensional model with topological mass generation that was found by
Dvali, Jackiw and Pi has recently been generalized to any even number of
dimensions (2n-dimensions) in a nontrivial manner in which a Stueckelberg-type
mass term is introduced [S. Deguchi and S. Hayakawa, Phys. Rev. D 77, 045003
(2008), arXiv:0711.1446]. The present paper deals with a self-contained model,
called here a modified hybrid model, proposed in this 2n-dimensional
generalization and considers the canonical formalism for this model. For the
sake of convenience, the canonical formalism itself is studied for a model
equivalent to the modified hybrid model by following the recipe for treating
constrained Hamiltonian systems. This formalism is applied to the canonical
quantization of the equivalent model in order to clarify observable and
unobservable particles in the model. The equivalent model (with a gauge-fixing
term) is converted to the modified hybrid model (with a corresponding
gauge-fixing term) in a Becchi-Rouet-Stora-Tyutin (BRST)-invariant manner.
Thereby it is shown that the Chern-Pontryagin density behaves as an observable
massive particle (or field). The topological mass generation is thus verified
at the quantum-theoretical level.


title:
The squares of the Laplacian-Dirichlet eigenfunctions are generically
  linearly independent

abstract:
  The paper deals with the genericity of domain-dependent spectral properties
of the Laplacian-Dirichlet operator. In particular we prove that, generically,
the squares of the eigenfunctions form a free family. We also show that the
spectrum is generically non-resonant. The results are obtained by applying
global perturbations of the domains and exploiting analytic perturbation
properties. The work is motivated by two applications: an existence result for
the problem of maximizing the rate of exponential decay of a damped membrane
and an approximate controllability result for the bilinear Schr\"odinger
equation.


title: Refined analysis of photon leptoproduction off spinless target

abstract:
  We calculate the differential cross section for real photon electroproduction
off spinless hadron which sevres as a main probe of the hadrons structure via
the concept of generalized parton distributions. Compared to previously
available computations performed with twist-three power accuracy, we exactly
accounted for all kinematical effects in hadron mass and momentum transfer
which arise from leptonic helicity amplitudes. We performed numerical studies
of these kinematical effects and demonstrated that in the valence quark region
and rather low virtualities of the hard photon which sets the factorization
scale, the available approximate results significantly overestimate the cross
section rates in comparison to exact formulas.


title: Scaling Identities for Solitons beyond Derrick's Theorem

abstract:
  New integral identities satisfied by topological solitons in a range of
classical field theories are presented. They are derived by considering
independent length rescalings in orthogonal directions, or equivalently, from
the conservation of the stress tensor. These identities are refinements of
Derrick's theorem.


title: Bose-Einstein condensation in dense quark matter

abstract:
  We consider the problem of Bose condensation of charged pions in QCD at
finite isospin chemical potential $\mu_I$ using the O(4)-symmetric linear sigma
model as an effective field theory for two-flavor QCD. Using the 2PI
$1/N$-expansion, we determine the quasiparticle masses as well as the pion and
chiral condensates as a function of the temperature and isospin chemical
potential in the chiral limit and at the physical point. At T=0, Bose
condensation takes place for chemical potentials larger than $m_{\pi}$. In the
chiral limit, the chiral condensate vanishes for any finite value of $\mu_I$.


title: Study of the quark-gluon matter by the PHOBOS experiment

abstract:
  The PHOBOS experiment at the Relativistic Heavy Ion Collider (RHIC) has
collected a large dataset of Au+Au, Cu+Cu, d+Au and p+p collisions in the
center of mass energy range spanning from 19 GeV/nucleon to 200 GeV/nucleon.
The almost full angular coverage of the PHOBOS detector allows the study of
particle production over 10 units pseudorapidity. The unique design of the
spectrometer enables reconstruction and identification of charged particles
down to very low transverse momenta.
  In this paper properties of the strongly interacting Quark-Gluon Plasma
(sQGP) created in the nucleus-nucleus collisions at the highest energy
available in laboratory are discussed. Results from the PHOBOS experiment on
jet suppression, very low pt particles production and elliptic flow are shown.
In more details are presented the most recent studies of the correlations of
charged particles with respect to a high-pt trigger particle, elliptic flow
fluctuations and two particle correlations.


title:
First-principles studies of water adsorption on graphene: The role of
  the substrate

abstract:
  We investigate the electronic properties of graphene upon water adsorption
and study the influence of the SiO2 substrate in this context using density
functional calculations. Perfect suspended graphene is rather insensitive to
H2O adsorbates, as doping requires highly oriented H2O clusters. For graphene
on a defective SiO2 substrate, we find a strongly different behavior: H2O
adsorbates can shift the substrate's impurity bands and change their
hybridization with the graphene bands. In this way, H2O can lead to doping of
graphene for much lower adsorbate concentrations than for free hanged graphene.
The effect depends strongly on the microscopic substrate properties.


title:
Non-empirical pairing energy density functional. First order in the
  nuclear plus Coulomb two-body interaction

abstract:
  We perform systematic calculations of pairing gaps in semi-magic nuclei
across the nuclear chart using the Energy Density Functional method and a {\it
non-empirical} pairing functional derived, without further approximation, at
lowest order in the two-nucleon vacuum interaction, including the Coulomb
force. The correlated single-particle motion is accounted for by the SLy4
semi-empirical functional. Rather unexpectedly, both neutron and proton pairing
gaps thus generated are systematically close to experimental data. Such a
result further suggests that missing effects, i.e. higher partial-waves of the
NN interaction, the NNN interaction and the coupling to collective
fluctuations, provide an overall contribution that is sub-leading as for
generating pairing gaps in nuclei. We find that including the Coulomb
interaction is essential as it reduces proton pairing gaps by up to 40%.


title: Master-modes in 3D turbulent channel flow

abstract:
  Turbulent flow fields can be expanded into a series in a set of basic
functions. The terms of such series are often called modes. A master- (or
determining) mode set is a subset of these modes, the time history of which
uniquely determines the time history of the entire turbulent flow provided that
this flow is developed. In the present work the existence of the
master-mode-set is demonstrated numerically for turbulent channel flow. The
minimal size of a master-mode set and the rate of the process of the recovery
of the entire flow from the master-mode set history are estimated. The velocity
field corresponding to the minimal master-mode set is found to be a good
approximation for mean velocity in the entire flow field. Mean characteristics
involving velocity derivatives deviate in a very close vicinity to the wall,
while master-mode two-point correlations exhibit unrealistic oscillations. This
can be improved by using a larger than minimal master-mode set. The near-wall
streaks are found to be contained in the velocity field corresponding to the
minimal master-mode set, and the same is true at least for the large-scale part
of the longitudinal vorticity structure. A database containing the time history
of a master-mode set is demonstrated to be an efficient tool for investigating
rare events in turbulent flows. In particular, a travelling-wave-like object
was identified on the basis of the analysis of the database. Two
master-mode-set databases of the time history of a turbulent channel flow are
made available online at http://www.dnsdata.afm.ses.soton.ac.uk/. The services
provided include the facility for the code uploaded by a user to be run on the
server with an access to the data.


title: Subdiffusive motion in kinetically constrained models

abstract:
  We discuss a kinetically constrained model in which real-valued local
densities fluctuate in time, as introduced recently by Bertin, Bouchaud and
Lequeux. We show how the phenomenology of this model can be reproduced by an
effective theory of mobility excitations propagating in a disordered
environment. Both excitations and probe particles have subdiffusive motion,
characterised by different exponents and operating on different time scales. We
derive these exponents, showing that they depend continuously on one of the
parameters of the model.


title: Phonon Density of States in Nd(O$_{1-x}$F$_{x}$)FeAs

abstract:
  We report measurements of the phonon density-of-states in iron oxypnictide
superconductors by inelastic x-ray scattering. A good agreement with ab-initio
calculations that do not take into account strong electronic correlations is
found, and an unpredicted softening of phonon branches under F doping of these
compounds is observed. Raman scattering experiments lead us to conclude that
this softening is not related to zone center phonons, and consequently imply an
important softening of the relevant phonon branches at finite momentum transfer
Q.


title:
Cosmological Structure Formation under MOND: a new numerical solver for
  Poisson's equation

abstract:
  We present a novel solver for an analogue to Poisson's equation in the
framework of modified Newtonian dynamics (MOND). This equation is highly
non-linear and hence standard codes based upon tree structures and/or FFT's in
general are not applicable; one needs to defer to multi-grid relaxation
techniques. After a detailed description of the necessary modifications to the
cosmological N-body code AMIGA (formerly known as MLAPM) we utilize the new
code to revisit the issue of cosmic structure formation under MOND. We find
that the proper (numerical) integration of a MONDian Poisson's equation has
some noticable effects on the final results when compared against simulations
of the same kind but based upon rather ad-hoc assumptions about the properties
of the MONDian force field. Namely, we find that the large-scale structure
evolution is faster in our revised MOND model leading to an even stronger
clustering of galaxies, especially when compared to the standard LCDM paradigm.


title:
Density functional theory for soft matter with mesoscopic length scale
  fluctuations included within field-theoretic formalism

abstract:
  Mesoscopic theory for soft-matter systems that combines density functional
and statistical field theory is derived from the microscopic theory by a
systematic coarse-graining procedure. Within the framework of this theory we
obtain the universal sequence of phases: disordered, bcc, hexagonal, lamellar,
inverted hexagonal, inverted bcc, disordered, for increasing density well below
the close-packing density. In addition to the above phases, more complex phases
may appear depending on the interaction potentials. For a particular form of
the short-range attraction long-range repulsion potential we find the
bicontinuous gyroid phase (Ia3d symmetry) that may be related to a network
forming cluster of colloids in a mixture of colloids and nonadsorbing polymers.


title: Switching On Magnetism in Ni-doped Graphene

abstract:
  Magnetic properties of graphenic carbon nanostructures, relevant for future
spintronic applications, depend crucially on doping and on the presence of
defects. In this paper we study the magnetism of the recently detected
substitutional Ni (Ni(sub)) impurities. Ni(sub) defects are non-magnetic in
flat graphene and develop a non-zero magnetic moment only in metallic
nanotubes. This surprising behavior stems from the peculiar curvature
dependence of the electronic structure of Ni(sub). A similar
magnetic/non-magnetic transition of Ni(sub) can be expected by applying
anisotropic strain to a flat graphene layer.


title:
Fermi Liquid parameters for dense nuclear matter in Effective Chiral
  Model

abstract:
  We calculate relativistic Fermi liquid parameters (RFLPs) for the description
of the properties of dense nuclear matter (DNM) using Effective Chiral Model.
Analytical expressions of Fermi liquid parameters (FLPs) are presented both for
the direct and exchange contributions. We present a comparative study of
perturbative calculation with mean field (MF) results. Moreover we go beyond
the MF so as to estimate the pionic contribution to the FLPs. Finally, we use
these parameters to estimate some of the bulk quantities like
incompressibility, sound velocity, symmetry energy etc. for DNM interacting via
exchange of $\sigma$, $\omega$ and $\pi$ meson. In addition, we also calculate
the energy densities and the binding energy curve for the nuclear matter.
Results for the latter have been found to be consistent with two loop
calculations reported recently within the same model.


title: Using mixed data in the inverse scattering problem

abstract:
  Consider the fixed-$\ell$ inverse scattering problem. We show that the zeros
of the regular solution of the Schr\"odinger equation, $r_{n}(E)$, which are
monotonic functions of the energy, determine a unique potential when the domain
of the energy is such that the $r_{n}(E)$ range from zero to infinity. This
suggests that the use of the mixed data of phase-shifts
  $\{\delta(\ell_0,k), k \geq k_0 \} \cup \{\delta(\ell,k_0), \ell \geq \ell_0
\}$, for which the zeros of the regular solution are monotonic in both domains,
and range from zero to infinity, offers the possibility of determining the
potential in a unique way.


title: Quantum discreteness is an illusion

abstract:
  I review arguments demonstrating how the concept of "particle" numbers arises
in the form of equidistant energy eigenvalues of coupled harmonic oscillators
representing free fields. Their quantum numbers (numbers of nodes of the wave
functions) can be interpreted as occupation numbers for objects with a formal
mass (defined by the field equation) and spatial wave number ("momentum")
characterizing classical field modes. A superposition of different oscillator
eigenstates, all consisting of n modes having one node, while all others have
none, defines a nondegenerate "n-particle wave function". Other discrete
properties and phenomena (such as particle positions and "events") can be
understood by means of the fast but smooth process of decoherence: the
irreversible dislocalization of superpositions. Any wave-particle dualism thus
becomes obsolete. The observation of individual outcomes of this decoherence
process in measurements requires either a subsequent collapse of the wave
function or a "branching observer" in accordance with the Schr\"odinger
equation - both possibilities applying clearly after the decoherence process.
Any probability interpretation of the wave function in terms of local elements
of reality, such as particles or other classical concepts, would open a
Pandora's box of paradoxes, as is illustrated by various misnomers that have
become popular in quantum theory.

categories: quant-ph cond-mat.quant-gas hep-th physics.pop-ph


title:
Statistical structure and $\gamma$-decay properties of closed shell Pb
  nuclei

abstract:
  The level densities and gamma-ray strength functions of 205-208Pb have been
measured with the Oslo method, utilizing the (3He, 3He' gamma) and (3He,alpha
gamma) reactions on the target nuclei 206Pb and 208Pb. The extracted level
densities are consistent with known discrete levels at low excitation energies.
The entropies and temperatures in the micro-canonical ensemble have been
deduced from the experimental level density. An average entropy difference of
Delta S ~ 1.8 k_B has been observed between 205Pb and 206Pb. The gamma-ray
strength functions in 205-208Pb are extracted and compared with two models;
however, none of them describe the data adequately. Intermediate structures
have been observed at lower gamma-ray energies in all the analyzed Pb nuclei.
These structures are less pronounced while moving from the doubly-magic nucleus
208Pb to 205Pb.


title: Quantum phase transition in a single-molecule quantum dot

abstract:
  Quantum criticality is the intriguing possibility offered by the laws of
quantum mechanics when the wave function of a many-particle physical system is
forced to evolve continuously between two distinct, competing ground states.
This phenomenon, often related to a zero-temperature magnetic phase transition,
can be observed in several strongly correlated materials such as heavy fermion
compounds or possibly high-temperature superconductors, and is believed to
govern many of their fascinating, yet still unexplained properties. In contrast
to these bulk materials with very complex electronic structure, artificial
nanoscale devices could offer a new and simpler vista to the comprehension of
quantum phase transitions. This long-sought possibility is demonstrated by our
work in a fullerene molecular junction, where gate voltage induces a crossing
of singlet and triplet spin states at zero magnetic field. Electronic tunneling
from metallic contacts into the $\rm{C_{60}}$ quantum dot provides here the
necessary many-body correlations to observe a true quantum critical behavior.


title:
Correlated $\Lambda t$ pairs from the absorption of $K^-$ at rest in
  light nuclei

abstract:
  Novel data from the $K^{-}_{stop}A$ absorption reaction in light nuclei
$^{6,7}$Li and $^{9}$Be are presented. The study aimed at finding $\Lambda t$
correlations. Regardless of $A$, the $\Lambda t$ pairs are preferentially
emitted in opposite directions. Reaction modeling predominantly assigns to the
$K^-_{stop}A\to\Lambda t(N)A'$ direct reactions the emission of the $\Lambda t$
pairs whose yield is found to range from $10^{-3}$ to $10^{-4}$$/K^-_{stop}$.
The experiment was performed with the FINUDA spectrometer at DA$\Phi$NE (LNF).


title:
Elastic and Chemical Contributions to the Stability of Magnetic Surface
  Alloys on Ru(0001)

abstract:
  We have used density functional theory to study the structural stability of
surface alloys. Our systems consist of a single pseudomorphic layer of
$M_xN_{1-x}$ on the Ru(0001) surface, where $M$ = Fe or Co, and $N$ = Pt, Au,
Ag, Cd, or Pb. Several of the combinations studied by us display a preference
for atomically mixed configurations over phase-segregated forms. We have also
performed further {\it ab initio} calculations to obtain the parameters
describing the elastic interactions between atoms in the alloy layer, including
the effective atomic sizes at the surface. We find that while elastic
interactions favor alloying for all the systems considered by us, in some cases
chemical interactions disfavor atomic mixing. We show that a simple criterion
(analogous to the Hume-Rothery first law for bulk alloys) need not necessarily
work for strain-stabilized surface alloys, because of the presence of
additional elastic contributions to the alloy heat of formation, that will tend
to oppose phase segregation.


title:
Cavity-QED based on collective magnetic dipole coupling: spin ensembles
  as hybrid two-level systems

abstract:
  We analyze the magnetic dipole coupling of an ensemble of spins to a
superconducting microwave stripline structure, incorporating a Josephson
junction based transmon qubit. We show that this system is described by an
embedded Jaynes-Cummings model: in the strong coupling regime, collective
spin-wave excitations of the ensemble of electrons pick up the nonlinearity of
the cavity mode, such that the two lowest eigenstates of the coupled spin-wave
+ microwave-cavity + Josephson-junction system define a hybrid two-level
system. The proposal described here enables the use of spin ensembles as qubits
which can be coherently manipulated and coupled using the same
nonlinear-cavity. Possibility of strong-coupling cavity-QED with
magnetic-dipole transitions opens up the possibility of extending previously
proposed quantum information processing protocols to spins in silicon or
graphene, without the need for single-electron confinement.