title: Information processing at single neuron level

abstract:
  Based on numerical simulation of Hodgkin and Huxley type neuron stimulated
from many synaptic inputs, an abstract concept of signal processing in
individual neuron is proposed. In the concept proposed, neuron performs binding
of synaptic inputs into a single output event, based on the degree of temporal
coherence between the inputs. Inhibition serves as controlling factor of this
type of binding.


title: Perturbative fragmentation

abstract:
  The Berger model of perturbative fragmentation of quarks to pions is improved
by providing an absolute normalization and keeping all terms in a (1-z)
expansion, which makes the calculation valid at all values of fractional pion
momentum z. We also replace the nonrelativistic wave function of a loosely
bound pion by the more realistic procedure of projecting to the light-cone pion
wave function, which in turn is taken from well known models. The full
calculation does not confirm the (1-z)^2 behavior of the fragmentation function
(FF) predicted in for $z>0.5$, and only works at very large z>0.95, where it is
in reasonable agreement with phenomenological FFs. Otherwise, we observe quite
a different z-dependence which grossly underestimates data at smaller z. The
disagreement is reduced after the addition of pions from decays of light vector
mesons, but still remains considerable. The process dependent higher twist
terms are also calculated exactly and found to be important at large z and/or
pT.


title: Spin Charge Separation in the Quantum Spin Hall State

abstract:
  The quantum spin Hall state is a topologically non-trivial insulator state
protected by the time reversal symmetry. We show that such a state always leads
to spin-charge separation in the presence of a $\pi$ flux. Our result is
generally valid for any interacting system. We present a proposal to
experimentally observe the phenomenon of spin-charge separation in the recently
discovered quantum spin Hall system.


title: Toward a statistical mechanics of four letter words

abstract:
  We consider words as a network of interacting letters, and approximate the
probability distribution of states taken on by this network. Despite the
intuition that the rules of English spelling are highly combinatorial (and
arbitrary), we find that maximum entropy models consistent with pairwise
correlations among letters provide a surprisingly good approximation to the
full statistics of four letter words, capturing ~92% of the multi-information
among letters and even "discovering" real words that were not represented in
the data from which the pairwise correlations were estimated. The maximum
entropy model defines an energy landscape on the space of possible words, and
local minima in this landscape account for nearly two-thirds of words used in
written English.

categories: q-bio.NC cs.CL physics.data-an physics.soc-ph


title: Design of experiments and biochemical network inference

abstract:
  Design of experiments is a branch of statistics that aims to identify
efficient procedures for planning experiments in order to optimize knowledge
discovery. Network inference is a subfield of systems biology devoted to the
identification of biochemical networks from experimental data. Common to both
areas of research is their focus on the maximization of information gathered
from experimentation. The goal of this paper is to establish a connection
between these two areas coming from the common use of polynomial models and
techniques from computational algebra.


title: Current-induced Spin Polarization in Two-Dimensional Hole Gas

abstract:
  We investigate the current-induced spin polarization in the two-dimensional
hole gas (2DHG) with the structure inversion asymmetry. By using the
perturbation theory, we re-derive the effective $k$-cubic Rashba Hamiltonian
for 2DHG and the generalized spin operators accordingly. Then based on the
linear response theory we calculate the current-induced spin polarization both
analytically and numerically with the disorder effect considered. We have found
that, quite different from the two-dimensional electron gas, the spin
polarization in 2DHG depends linearly on Fermi energy in the low doping regime,
and with increasing Fermi energy, the spin polarization may be suppressed and
even changes its sign. We predict a pronounced peak of the spin polarization in
2DHG once the Fermi level is somewhere between minimum points of two spin-split
branches of the lowest light-hole subband. We discuss the possibility of
measurements in experiments as regards the temperature and the width of quantum
wells.


title:
Passively self-error-rejecting qubit transmission over a
  collective-noise channel

abstract:
  We propose a passively self-error-rejecting single-qubit transmission scheme
for an arbitrary polarization state of a single qubit over a collective-noise
channel, without resorting to additional qubits and entanglement. By splitting
a single qubit into some wavepackets with some Mach-Zehnder interferometers, we
can obtain an uncorrupted state with a success probability approaching 100% via
postselection in different time bins, independent of the parameters of
collective noise. It is simpler and more flexible than the schemes utilizing
decoherence-free subspace and those with additional qubits. One can directly
apply this scheme to almost all quantum communication protocols based on single
photons or entangled photon systems against a collective noise.


title:
More on Meta-Stable Brane Configuration by Quartic Superpotential for
  Fundamentals

abstract:
  For the case where the gauge theory superpotential has a quartic term as well
as the mass term for quarks, the nonsupersymmetric meta-stable brane
configuration was found recently. By adding the orientifold 6-planes and the
extra fundamental flavors to this brane configuration, we describe the
meta-stable nonsupersymmetric vacua of the gauge theory with antisymmetric
flavor as well as fundamental flavors in type IIA string theory.


title: On the Maximum Span of Fixed-Angle Chains

abstract:
  Soss proved that it is NP-hard to find the maximum 2D span of a fixed-angle
polygonal chain: the largest distance achievable between the endpoints in a
planar embedding. These fixed-angle chains can serve as models of protein
backbones. The corresponding problem in 3D is open. We show that three special
cases of particular relevance to the protein model are solvable in polynomial
time. When all link lengths and all angles are equal, the maximum 3D span is
achieved in a flat configuration and can be computed in constant time. When all
angles are equal and the chain is simple (non-self-crossing), the maximum flat
span can be found in linear time. In 3D, when all angles are equal to 90 deg
(but the link lengths arbitrary), the maximum 3D span is in general nonplanar
but can be found in quadratic time.


title:
Stable and deterministic quantum key distribution based on differential
  phase shift

abstract:
  We present a stable and deterministic quantum key distribution (QKD) system
based on differential phase shift. With three cascaded Mach-Zehnder
interferometers with different arm-length differences for creating key, its key
creation efficiency can be improved to be 7/8, more than other systems. Any
birefringence effects and polarization-dependent losses in the long-distance
fiber are automatically compensated with a Faraday mirror. Added an
eavesdropping check, this system is more secure than some other
phase-coding-based QKD systems. Moreover, the classical information exchanged
is reduces largely and the modulation of phase shifts is simplified. All these
features make this QKD system more convenient than others in a practical
application.


title:
On the Latitude Distribution of the Polar Magnetic Flux as Observed by
  SOLIS-VSM

abstract:
  Magnetograms from the Vector SpectroMagnetograph (VSM) of the Synoptic
Optical Long-term Investigations of the Sun (SOLIS) project are utilized to
study the latitude distribution of magnetic flux elements as a function of
latitude in the polar solar caps. We find that the density distribution of the
magnetic flux normalized by the surface of the polar cap and averaged over
months decreases close to the solar poles. This trend is more pronounced when
considering only flux elements with relatively large size. The flux density of
the latter is relatively flat from the edge of the polar cap up to latitudes of
70$^\circ$--75$^\circ$ and decreases significantly to the solar pole. The
density of smaller flux features is more uniformly distributed although the
decrease is still present but less pronounced. This result is important in
studying meridional flows that bring the magnetic flux from lower to higher
solar latitudes resulting in the solar cycle reversal. The results are also of
importance in studying polar structures contributing to the fast solar wind,
such as polar plumes.


title: An Abelian Category of Motivic Sheaves

abstract:
  The goal of this paper is to construct a category of motivic "sheaves" on an
algebraic variety defined over a subfield of C, using Nori's method. This
categoryis abelian and it possesses faithful exact realization functors to the
categoriesof constructible sheaves for the classical and etale topologies.
Moreover, there is a tannakian subcategory of motivic local systems with a
realization functor into the category of variations of mixed Hodge structures.
Conversely, all basic geometric examples of the latter come from this motivic
category.


title: Z2 electric strings and center vortices in SU(2) lattice gauge theory

abstract:
  We study the representations of SU(2) lattice gauge theory in terms of sums
over the worldsheets of center vortices and Z2 electric strings, i.e. surfaces
which open on the Wilson loop. It is shown that in contrast to center vortices
the density of electric Z2 strings diverges in the continuum limit of the
theory independently of the gauge fixing, however, their contribution to the
Wilson loop yields physical string tension due to non-positivity of their
statistical weight in the path integral, which is in turn related to the
presence of Z2 topological monopoles in the theory.


title:
Production and Decay of the Ge73-m Metastable State in a Low-Background
  Germanium Detector

abstract:
  The $\ge73m$ metastable states decay with a very characteristic signature
which allow them to be tagged event-by-event. Studies were performed using data
taken with a high-purity germanium detector in a low-background laboratory near
a nuclear power reactor core where $\nuebar$-flux was $\rm{6.4 \times 10^{12} ~
cm^{-2} s^{-1}}$. The measured average and equilibrium production rates of
$\ge73m$ were $\rm{(8.7 \pm 0.4)}$ and $\rm{(6.7 \pm 0.3) ~ kg^{-1} day^{-1}}$,
respectively. The production channels were studied and identified. By studying
the difference in the production of $\ge73m$ between the reactor ON and OFF
spectra, the limiting sensitivities at the range of $\rm{\sim 10^{-42} -
10^{-43} ~ cm^2}$ for the cross-sections of neutrino-induced nuclear
transitions were derived. The dominant background are due to $\beta$-decays of
cosmic-ray induced $^{73}$Ga. The prospects of enhancing the sensitivities at
underground locations are discussed.


title: Density Statistics of Compressible MHD Turbulence

abstract:
  Density is the turbulence statistics that is most readily available from
observations. Different regimes of turbulence correspond to different density
spectra. For instance, the viscosity-damped regime of MHD turbulence relevant,
for instance, to partially ionized gas, can be characterized by shallow and
very anisotropic spectrum of density. This spectrum can result in substantial
variations of the column densities. Addressing MHD turbulence in the regime
when viscosity is not important over the inertial range, we demonstrate with
numerical simulations that it is possible to reproduce both the observed
Kolmogorov spectrum of density fluctuations observed in ionized gas by
measuring scintillations and more shallow spectra that are obtained through the
emission measurements. We show that in supersonic turbulence the high density
peaks dominate shallow isotropic spectrum, while the small-scale underlying
turbulence that fills most of the volume has the Kolmogorov spectrum and
demonstrates scale-dependent anisotropy. The limitations of the spectrum in
studying turbulence induce searches of alternative statistics. We demonstrate
that a measure called "bispectrum" may be a promising tool. Unlike spectrum,
the bispectrum preserves the information about wave phases.


title:
Alignment of Dust with Magnetic Inclusions: Radiative Torques and
  Superparamagnetic Barnett and Nuclear Relaxation

abstract:
  We consider grains with superparamagnetic inclusions and report two new
condensed matter effects that can enhance the internal relaxation of the energy
of a wobbling grain, namely, superparamagnetic Barnett relaxation, as well as,
an increase of frequencies for which nuclear relaxation becomes important. This
findings extends the range of grain sizes for which grains are thermally
trapped, i.e. rotate thermally, in spite of the presence of uncompensated
pinwheel torques. In addition, we show that the alignment of dust grains by
radiative torques gets modified for superparamagnetic grains, with grains
obtaining perfect alignment with respect to magnetic fields as soon as the
grain gaseous randomization time gets larger than that of paramagnetic
relaxation. The same conclusion is valid for the mechanical alignment of
helical grains. If observations confirm that the degrees of alignment are
higher than radiative torques can produce alone, this may be a proof of the
presence of superparamagentic inclusions.


title: Radiative torques alignment in the presence of pinwheel torques

abstract:
  We study the alignment of grains subject to both radiative torques and
pinwheel torques while accounting for thermal flipping of grains. By pinwheel
torques we refer to all systematic torques that are fixed in grain body axes,
including the radiative torques arising from scattering and absorption of
isotropic radiation. We discuss new types of pinwheel torques, which are
systematic torques arising from infrared emission and torques arising from the
interaction of grains with ions and electrons in hot plasma. We show that both
types of torques are long-lived, i.e. may exist longer than gaseous damping
time. We compare these torques with the torques introduced by E. Purcell,
namely, torques due to H$_2$ formation, the variation of accommodation
coefficient for gaseous collisions and photoelectric emission. Furthermore, we
revise the Lazarian & Draine model for grain thermal flipping. We calculate
mean flipping timescale induced by Barnett and nuclear relaxation for both
paramagnetic and superparamagnetic grains, in the presence of stochastic
torques associated with pinwheel torques, e.g. the stochastic torques arising
from H$_2$ formation, and gas bombardment. We show that the combined effect of
internal relaxation and stochastic torques can result in fast flipping for
sufficiently small grains and, because of this, they get thermally trapped,
i.e. rotate thermally in spite of the presence of pinwheel torques. For
sufficiently large grains, we show that the pinwheel torques can increase the
degree of grain alignment achievable with the radiative torques by increasing
the magnitude of the angular momentum of low attractor points and/or by driving
grains to new high attractor points.


title:
Structure of the $(0^+,1^+)$ mesons $B_{s0}$ and $B_{s1}$, and the
  strong coupling constants $g_{B_{s0} B K}$ and $g_{B_{s1} B^* K}$

abstract:
  In this article, we take the point of view that the bottomed $(0^+,1^+)$
mesons $B_{s0}$ and $B_{s1}$ are the conventional $b\bar{s}$ meson, and
calculate the strong coupling constants $g_{B_{s0} B K}$ and $g_{B_{s1} B^* K}$
with the light-cone QCD sum rules. The numerical values of strong coupling
constants $g_{B_{s1} B^* K}$ and $g_{B_{s0} B K}$ are very large, and support
the hadronic dressing mechanism. Just like the scalar mesons $f_0(980)$,
$a_0(980)$, $D_{s0}$ and axial-vector meson $D_{s1}$, the $(0^+,1^+)$ bottomed
mesons $B_{s0}$ and $B_{s1}$ may have small $b\bar{s}$ kernels of the typical
$b\bar{s}$ meson size, the strong couplings to the hadronic channels (or the
virtual mesons loops) may result in smaller masses than the conventional
$b\bar{s}$ mesons in the potential quark models, and enrich the pure $b\bar{s}$
states with other components.


title:
Power-law cosmological solution derived from DGP brane with a brane
  tachyon field

abstract:
  By studying a tachyon field on the DGP brane model, in order to embed the 4D
standard Friedmann equation with a brane tachyon field in 5D bulk, the metric
of the 5D spacetime is presented. Then, adopting the inverse square potential
of tachyon field, we obtain an expanding universe with power-law on the brane
and an exact 5D solution.


title:
Two-gap superconductivity in single crystal Lu$_2$Fe$_3$Si$_5$ from
  penetration depth measurements

abstract:
  Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode
resonator technique in Meissner and mixed states. Temperature dependence of the
superfluid density provides strong evidence for the two-gap superconductivity
with almost equal contributions from each gap of magnitudes
$\Delta_1/k_BT_c=1.86$ and $\Delta_1/k_BT_c=0.54$. In the vortex state, pinning
strength shows unusually strong temperature dependence and is non-monotonic
with the magnetic field (peak effect). The irreversibility line is sharply
defined and is quite distant from the $H_{c2}(T)$, which hints on to enhanced
vortex fluctuations in this two-gap system. Altogether our findings provide
strong electromagnetic - measurements support to the two-gap superconductivity
in Lu$_2$Fe$_3$Si$_5$ previously suggested from specific heat measurements.


title:
Partitioning 3-edge-colored complete equi-bipartite graphs by
  monochromatic trees under a color degree condition

abstract:
  The monochromatic tree partition number of an $r$-edge-colored graph $G$,
denoted by $t_r(G)$, is the minimum integer $k$ such that whenever the edges of
$G$ are colored with $r$ colors, the vertices of $G$ can be covered by at most
$k$ vertex-disjoint monochromatic trees. In general, to determine this number
is very difficult. For 2-edge-colored complete multipartite graph, Kaneko,
Kano, and Suzuki gave the exact value of $t_2(K(n_1,n_2,...,n_k))$. In this
paper, we prove that if $n\geq 3$, and K(n,n) is 3-edge-colored such that every
vertex has color degree 3, then $t_3(K(n,n))=3.$


title: Crystal Plasticity for Dynamic Loading at High Pressures and Strains

abstract:
  A crystal plasticity theory was developed for use in simulations of dynamic
loading at high pressures and strain rates. At pressures of the order of the
bulk modulus, compressions o(100%) may be induced. At strain rates o(10^9)/s or
higher, elastic strains may reach o(10%), which may change the orientation of
the slip systems significantly with respect to the stress field. Elastic strain
rather than stress was used in defining the local state, providing a more
direct connection with electronic structure predictions and consistency with
the treatment of compression in initial value problems in continuum dynamics.
Plastic flow was treated through explicit slip systems, with flow on each
system taken to occur by thermally-activated random jumps biased by the
resolved stress. Compared with simple Arrhenius rates, the biased random jumps
caused significant differences in plastic strain rate as a function of
temperature and pressure, and provided a seamless transition to the ultimate
theoretical strength of the material. The behavior of the theory was
investigated for matter with approximate properties for Ta, demonstrating the
importance of the high pressure, high strain rate contributions.


title: Evaluation of a ln tan integral arising in quantum field theory

abstract:
  We analytically evaluate a dilogarithmic integral that is prototypical of
volumes of ideal tetrahedra in hyperbolic geometry. We additionally obtain new
representations of the Clausen function Cl_2 and the Catalan constant
G=Cl_2(\pi/2), as well as new relations between sine and Clausen function
values.


title:
On a three-dimensional symmetric Ising tetrahedron, and contributions to
  the theory of the dilogarithm and Clausen functions

abstract:
  Perturbative quantum field theory for the Ising model at the three-loop level
yields a tetrahedral Feynman diagram C(a,b) with masses a and b and four other
lines with unit mass. The completely symmetric tetrahedron C^Tet \equiv C(1,1)
has been of interest from many points of view, with several representations and
conjectures having been given in the literature. We prove a conjectured
exponentially fast convergent sum for C(1,1), as well as a previously empirical
relation for C(1,1) as a remarkable difference of Clausen function values. Our
presentation includes Propositions extending the theory of the dilogarithm Li_2
and Clausen Cl_2 functions, as well as their relation to other special
functions of mathematical physics. The results strengthen connections between
Feynman diagram integrals, volumes in hyperbolic space, number theory, and
special functions and numbers, specifically including dilogarithms, Clausen
function values, and harmonic numbers.


title:
Strong lensing of submillimetre galaxies: A tracer of foreground
  structure?

abstract:
  The steep source counts and negative K-corrections of bright submillimetre
galaxies (SMGs) suggest that a significant fraction of those observed at high
flux densities may be gravitationally lensed, and that the lensing objects may
often lie at redshifts above 1, where clusters of galaxies are difficult to
detect through other means. In this case follow-up of bright SMGs may be used
to identify dense structures along the line of sight. Here we investigate the
probability for SMGs to experience strong lensing, using the latest N-body
simulations and observed source flux and redshift distributions. We find that
almost all high redshift sources with a flux density above 100mJy will be
lensed, if they are not relatively local galaxies. We also give estimates of
the fraction of sources experiencing strong lensing as a function of observed
flux density. This has implications for planning follow-up observations for
bright SMGs discovered in future surveys with SCUBA-2 and other instruments.
The largest uncertainty in these calculations is the maximum allowed lensing
amplification, which is dominated by the presently unknown spatial extent of
SMGs.


title:
Estimating Signals with Finite Rate of Innovation from Noisy Samples: A
  Stochastic Algorithm

abstract:
  As an example of the recently-introduced concept of rate of innovation,
signals that are linear combinations of a finite number of Diracs per unit time
can be acquired by linear filtering followed by uniform sampling. However, in
reality, samples are rarely noiseless. In this paper, we introduce a novel
stochastic algorithm to reconstruct a signal with finite rate of innovation
from its noisy samples. Even though variants of this problem has been
approached previously, satisfactory solutions are only available for certain
classes of sampling kernels, for example kernels which satisfy the Strang-Fix
condition. In this paper, we consider the infinite-support Gaussian kernel,
which does not satisfy the Strang-Fix condition. Other classes of kernels can
be employed. Our algorithm is based on Gibbs sampling, a Markov chain Monte
Carlo (MCMC) method. Extensive numerical simulations demonstrate the accuracy
and robustness of our algorithm.


title: Cryptanalysis of a Chaotic Image Encryption Algorithm

abstract:
  Line map, an invertible, two-dimensional chaotic encryption algorithm was
introduced recently. In this paper, we propose several weaknesses of the method
based on standard cryptanalytic attacks. We perform a side-channel attack by
observing the execution time of the encryption algorithm and successfully
reduce the key space by a factor of 10^4 for a key length of 16 digits. We find
the existence of equivalent keys which reduce the key space by a significant
margin, even in the absence of any attack. Also, we find that the ciphertext is
not sensitive to small changes in the plaintext due to poor diffusion.


title:
Size-independent differences between the mean of discrete stochastic
  systems and the corresponding continuous deterministic systems

abstract:
  In this paper I show that, for a class of reaction networks, the discrete
stochastic nature of the reacting species and reactions results in qualitative
and quantitative differences between the mean of exact stochastic simulations
and the prediction of the corresponding deterministic system. The differences
are independent of the number of molecules of each species in the system under
consideration. These reaction networks are open systems of chemical reactions
with no zero-order reaction rates systems. They are characterized by at least
two stationary points, one of which is a nonzero stable point, and one unstable
trivial solution (stability based on a linear stability analysis of the
deterministic system). Starting from a nonzero initial condition, the
deterministic system never reaches the zero stationary point due to its
unstable nature. In contrast, the result presented here proves that this
zero-state is the only stable stationary state for the discrete stochastic
system. This result generalizes previous theoretical studies and simulations of
specific systems and provides a theoretical basis for analyzing a class of
systems that exhibit such inconsistent behavior. This result has implications
in the simulation of infection, apoptosis, and population kinetics, as it can
be shown that for certain models the stochastic simulations will always yield
different predictions for the mean behavior than the deterministic simulations.


title: On The Isoperimetric Spectrum of Graphs and Its Approximations

abstract:
  In this paper we consider higher isoperimetric numbers of a (finite directed)
graph. In this regard we focus on the $n$th mean isoperimetric constant of a
directed graph as the minimum of the mean outgoing normalized flows from a
given set of $n$ disjoint subsets of the vertex set of the graph. We show that
the second mean isoperimetric constant in this general setting, coincides with
(the mean version of) the classical Cheeger constant of the graph, while for
the rest of the spectrum we show that there is a fundamental difference between
the $n$th isoperimetric constant and the number obtained by taking the minimum
over all $n$-partitions. In this direction, we show that our definition is the
correct one in the sense that it satisfies a Federer-Fleming-type theorem, and
we also define and present examples for the concept of a supergeometric graph
as a graph whose mean isoperimetric constants are attained on partitions at all
levels. Moreover, considering the ${\bf NP}$-completeness of the isoperimetric
problem on graphs, we address ourselves to the approximation problem where we
prove general spectral inequalities that give rise to a general Cheeger-type
inequality as well. On the other hand, we also consider some algorithmic
aspects of the problem where we show connections to orthogonal representations
of graphs and following J.~Malik and J.~Shi ($2000$) we study the close
relationships to the well-known $k$-means algorithm and normalized cuts method.


title:
Studies of regular and random magnetic fields in the ISM: statistics of
  polarization vectors and the Chandrasekhar-Fermi technique

abstract:
  Polarimetry is extensively used as a tool to trace the interstellar magnetic
field projected on the plane of sky. Moreover, it is also possible to estimate
the magnetic field intensity from polarimetric maps based on the
Chandrasekhar-Fermi method. In this work, we present results for turbulent,
isothermal, 3-D simulations of sub/supersonic and sub/super-Alfvenic cases.
With the cubes, assuming perfect grain alignment, we created synthetic
polarimetric maps for different orientations of the mean magnetic field with
respect to the line of sight (LOS). We show that the dispersion of the
polarization angle depends on the angle of the mean magnetic field regarding
the LOS and on the Alfvenic Mach number. However, the second order structure
function of the polarization angle follows the relation $SF \propto
l^{\alpha}$, $\alpha$ being dependent exclusively on the Alfvenic Mach number.
The results show an anti-correlation between the polarization degree and the
column density, with exponent $\gamma \sim -0.5$, in agreement with
observations, which is explained by the increase in the dispersion of the
polarization angle along the LOS within denser regions. However, this effect
was observed exclusively on supersonic, but sub-Alfvenic, simulations. For the
super-Alfvenic, and the subsonic model, the polarization degree showed to be
intependent on the column density. Our major quantitative result is a
generalized equation for the CF method, which allowed us to determine the
magnetic field strength from the polarization maps with errors $< 20%$. We also
account for the role of observational resolution on the CF method.


title: Reconstructing the interaction rate in holographic models of dark energy

abstract:
  We reconstruct the interaction rate of the holographic dark energy model
recently proposed by Zimdahl and Pav\'{o}n \cite{wd} in the redshift interval
$0 < z < 1.8$ with observational data from supernovae type Ia, baryon acoustic
oscillations, gas mass fraction in galaxy clusters, and the growth factor. It
shows a reasonable behavior in the sense that it increases with expansion from
a small or vanishing value in the long past but starts decreasing at recent
times. The later feature suggests that the equation of state parameter of dark
energy does not cross the phantom divide.


title:
On Certain Hypotheses in Optimal Control Theory and the Relationship of
  the Maximum Principle with the Dynamic Programming Method Proposed by L. I.
  Rozonoer

abstract:
  In this paper we will study three hypotheses proposed by L. I. Rozonoer
(Automation and Remote Control, 2003, vol.64, no.8, pp.1237--1240) in optimal
control theory in order to derive conditions for the existence of an optimal
control under all initial conditions, and the relationships between Pontryagin
maximum principle and the dynamic programming method.


title: Smooth Renyi Entropies and the Quantum Information Spectrum

abstract:
  Many of the traditional results in information theory, such as the channel
coding theorem or the source coding theorem, are restricted to scenarios where
the underlying resources are independent and identically distributed (i.i.d.)
over a large number of uses. To overcome this limitation, two different
techniques, the information spectrum method and the smooth entropy framework,
have been developed independently. They are based on new entropy measures,
called spectral entropy rates and smooth entropies, respectively, that
generalize Shannon entropy (in the classical case) and von Neumann entropy (in
the more general quantum case). Here, we show that the two techniques are
closely related. More precisely, the spectral entropy rate can be seen as the
asymptotic limit of the smooth entropy. Our results apply to the quantum
setting and thus include the classical setting as a special case.


title: Cayley 4-form, comass, and triality isomorphisms

abstract:
  Following an idea of Dadok, Harvey and Lawson, we apply the triality property
of SO(8) to study the comass of certain self-dual 4-forms on R^8. In
particular, we prove that the Cayley 4-form has comass 1 and that any self-dual
4-form realizing the maximal Wirtinger ratio is SO(8)-conjugate to the Cayley
4-form. We also use triality to prove that the stabilizer in SO(8) of the
Cayley form is Spin(7). The results have applications in systolic geometry,
calibrated geometry, and Spin(7) manifolds.


title: Complex product manifolds cannot be negatively curved

abstract:
  We show that if $M = X \times Y$ is the product of two complex manifolds (of
positive dimensions), then $M$ does not admit any complete K\"ahler metric with
bisectional curvature bounded between two negative constants. More generally, a
locally-trivial holomorphic fibre-bundle does not admit such a metric.


title: An elementary approach to some rigidity theorems

abstract:
  Using elementary comparison geometry, we prove:
  Let $(M,g)$ be a simply-connected complete Riemannian manifold of dimension
$\ge 3$. Suppose that the sectional curvature $K$ satisfies
  $ -1-s(r) \le K \le -1$, where $r$ denotes distance to a fixed point in
  $M$. If $\lim_{r \rt \infty} e^{2r}s(r) =0$, then $(M,g)$ has to be isometric
to ${\mathbb H}^n$.
  The same proof also yields that if $K$ satisfies $-s(r) \le K \le 0$ where
$\lim_{r \rt \infty} r^2s(r)=0$, then $(M,g)$ is isometric to $\R^n$, a result
due to Greene and Wu. Our second result is a local one: Let $(M,g)$ be any
Riemannian manifold. For $a \in \R$, if $K \le a$ on a geodesic ball $B_p(R)$
in $M$ and $K = a$ on $\partial B_p(R)$, then $K= a $ on $B_p(R)$.


title:
Non-linear equations for electron waves in Maxwellian low-collision
  ion-electron plasmas

abstract:
  The before described general principles and methodology of calculating
electron wave propagation in homogeneous isotropic half-infinity slab of
Maxwellian plasma with indefinite but in principal value sense taken integrals
in characteristic equations, and the use of 2D Laplace transform method are
applied to an evaluation of collision damping decrements of plane electron
longitudinal and transverse waves. Damping decrement tends to infinity when the
wave frequency tends to electron Langmuir frequency from above values. We
considered recurrent relations for amplitudes of the overtones which form in
their sum the all solution of the plasma wave non-linear equations including
collision damping and quadratic (non-linear) terms. Collisionless damping at
frequencies more the Langmuir one is possible only in non-Maxwellian plasmas.


title: Data Tables for Lorentz and CPT Violation

abstract:
  This work tabulates measured and derived values of coefficients for Lorentz
and CPT violation in the Standard-Model Extension. Summary tables are extracted
listing maximal attained sensitivities in the matter, photon, neutrino, and
gravity sectors. Tables presenting definitions and properties are also
compiled.


title:
Constraints on the average magnetic field strength of relic radio
  sources 0917+75 and 1401-33 from XMM-Newton observations

abstract:
  We observed two relic radio sources, 0917+75 and 1401-33, with the XMM-Newton
X-ray observatory. We did not detect any X-ray emission, thermal or
non-thermal, in excess of the local background level from either target. This
imposes new upper limits on the X-ray flux due to inverse Compton scattering of
photons from the cosmic microwave background by relativistic electrons in the
relic sources, and new lower limits on the magnetic field strength from the
relative strength of the radio and X-ray emission. The combination of radio and
X-ray observations provides a measure of the magnetic field independent of
equipartition or minimum energy assumptions. Due to increasing sensitivity of
radio observations, the known population of cluster relics has been growing;
however, studies of non-thermal X-ray emission from relics remain scarce. Our
study adds to the small sample of relics studied in X-rays. In both relics, our
field strength lower limits are slightly larger than estimates of the
equipartition magnetic field.


title: Is Randomness "Native" to Computer Science?

abstract:
  We survey the Kolmogorov's approach to the notion of randomness through the
Kolmogorov complexity theory. The original motivation of Kolmogorov was to give
up a quantitative definition of information. In this theory, an object is
randomness in the sense that it has a large information content. Afterwards, we
present parts of the work of Martin-Lof, Schnorr, Chaitin and Levin which
supply a mathematical notion of randomness throughout diverse theories from the
the 60' up to recently.


title:
Cosmic microwave background constraints on a decaying cosmological term
  related to the thermal evolution

abstract:
  We constrain the thermal evolution of the universe with a decaying
cosmological term by using the method of the analysis for the Wilkinson
Microwave Anisotropy Probe (WMAP) observation data. The cosmological term is
assumed to be a function of the scale factor that increases toward the early
universe, and the radiation energy density is lower compared to that in the
model with the standard cosmological "constant" (LCDM). The decrease in the
radiation density affects the thermal history of the universe; e.g. the photon
decoupling occurs at higher-z compared to the case of the standard LCDM model.
As a consequence, a decaying cosmological term affects the cosmic microwave
background anisotropy. Thanks to the Markov-chain Monte Carlo method, we
compare the angular power spectrum in the decaying LCDM model with the CMB
data, and we get severe constraints on parameters of the model.


title: Asymptotic freedom in low-energy quantum gravity

abstract:
  It is suggested in the model of low-energy quantum gravity by the author,
that the background of super-strong interacting gravitons exists. It is shown
here that micro-particles at very small distances should be almost free if the
gravitational attraction is caused by a pressure of these gravitons.


title:
First-order coherent resonant tunneling through an interacting
  coupled-quantum-dot interferometer: generic quantum rate equations and
  current noise

abstract:
  We carry out a detailed analysis of coherent resonant tunneling through two
coupled quantum dots (CQD) in a parallel arrangement in the weak tunneling
limit. We establish a set of quantum rate equations (QREs) in terms of the
eigenstate-representation by means of a generic quantum Langevin equation
approach, which is valid for arbitrary bias-voltage, temperature, and interdot
hopping strength. Based on linear-response theory, we further derive the
current and frequency-independent shot noise formulae. Our results reveal that
a previously used formula for evaluating Schottky-type noise of a "classical"
single-electron transistor is a direct result of linear-response theory, and it
remains applicable for small quantum devices with internal coupling. Our
numerical calculations show some interesting transport features (i) for a
series-CQD: the appearance of a NDC due to the bias-voltage-induced shifting of
bare levels or a finite interdot Coulomb repulsion, and (ii) for a parallel CQD
in strong interdot Coulomb repulsion regime: finite-bias-induced AB
oscillations of current, and magnetic-flux-controllable negative differential
conductance and a huge Fano factor.


title: The far-IR view of Sgr B2 and Orion KL

abstract:
  We summarize the main highlights from ISO observations towards Sgr B2 and
Orion KL in the far-IR domain (~43 to 197 um). Both Star-Forming Regions are
among the best sources to construct a template for more distant and unresolved
regions (e.g., extragalactic). We stress some peculiarities in the
interpretation (excitation and radiative transfer) of far-IR spectral lines and
dust continuum emission.


title: Functions and Relations for an Evolving Star with Spherical Symmetry

abstract:
  In this paper, we drive and simplify some important equations and relations
for an evolving star with spherical symmetry, and then give some simple
analysis for their properties and implications. In the light-cone coordinate
system, these equations and relations have a normal and neat form which is much
accessible than the usual Einstein field equation. So they may be helpful for
students to study general relativity and for researchers to do further
discussion.


title:
Electron correlation effects in the dipole polarizabilities of the
  ground states of Be, Mg, Ca, Sr, Ba and Yb

abstract:
  We investigate the role of electron correlation effects in the electric
dipole polarizabilities of the ground states of the alkaline earth and
ytterbium atoms by employing the relativistic coupled-cluster (RCC) theory.
These effects are incorporated via the residual Coulomb interaction to all
orders in the RCC singles and doubles approximation. The perturbed
wavefunctions used in the calculations of the polarizabilities are obtained by
directly solving the first order perturbed RCC equations, thereby avoiding the
sum-over-states approach. Our results are compared with other calculations and
available experimental data.


title:
Triaxial projected shell model study of gamma-vibrational bands in
  even-even Er isotopes

abstract:
  We expand the triaxial projected shell model basis to include
triaxially-deformed multi-quasiparticle states. This allows us to study the
yrast and gamma-vibrational bands up to high spins for both gamma-soft and
well-deformed nuclei. As the first application, a systematic study of the
high-spin states in Er-isotopes is performed. The calculated yrast and
gamma-bands are compared with the known experimental data, and it is shown that
the agreement between theory and experiment is quite satisfactory. The
calculation leads to predictions for bands based on one- and two-gamma phonon
where current data are still sparse. It is observed that gamma-bands for
neutron-deficient isotopes of 156Er and 158Er are close to the yrast band, and
further these bands are predicted to be nearly degenerate for high-spin states.


title: Walk versus Wait: The Lazy Mathematician Wins

abstract:
  In this recreational mathematics note, we address a simple, yet instructive
question:
  Justin has to travel a distance of d miles along a bus route. Along this
route, there are n bus stops i, each spaced at a distance of d_i from the
starting point. At each bus stop, Justin is faced with a choice: to walk or to
wait. If he walks on, he can still catch a bus at the next bus stop--but if a
bus passes him while he walks, he is almost assured a longer wait.
  We model Justin's decision constraint and completely solve the model in a
special case. The answer is intuitive: the optimal strategy is the laziest.


title: Curvature interaction in collective space

abstract:
  For the Riemannian space, built from the collective coordinates used within
nuclear models, an additional interaction with the metric is investigated,
using the collective equivalent to Einstein's curvature scalar. The coupling
strength is determined using a fit with the AME2003 ground state masses. An
extended finite-range droplet model including curvature is introduced, which
generates significant improvements for light nuclei and nuclei in the
trans-fermium region.


title:
The effect of long range interactions on the stability of classical and
  quantum solids

abstract:
  We generalise the celebrated Peierls' argument to study the stability of a
long-range interacting classical solid. Long-range interaction implies that all
the atomic oscillators are coupled to each other via a harmonic potential,
though the coupling strength decays as a power-law $1/x^{\alpha}$, where $x$ is
the distance between the oscillators. We show that for the range parameter
$\alpha <2$, the long-range interaction dominates and the one-dimensional
system retains a crystalline order even at a finite temperature whereas for
$\alpha \geq2$, the long-range crystalline order vanishes even at an
infinitesimally small temperature. We also study the effect of quantum
fluctuations on the melting behaviour of a one-dimensional solid at T=0,
extending Peierls' arguments to the case of quantum oscillators.


title: Metrisability of two-dimensional projective structures

abstract:
  We carry out the programme of R. Liouville \cite{Liouville} to construct an
explicit local obstruction to the existence of a Levi--Civita connection within
a given projective structure $[\Gamma]$ on a surface. The obstruction is of
order 5 in the components of a connection in a projective class. It can be
expressed as a point invariant for a second order ODE whose integral curves are
the geodesics of $[\Gamma]$ or as a weighted scalar projective invariant of the
projective class. If the obstruction vanishes we find the sufficient conditions
for the existence of a metric in the real analytic case. In the generic case
they are expressed by the vanishing of two invariants of order 6 in the
connection. In degenerate cases the sufficient obstruction is of order at most
8.


title:
Lepton flavor violating $l_i\to l_j \gamma\gamma$ decays induced by
  scalar unparticle

abstract:
  We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays
in the case that the lepton flavor violation is induced by the scalar
unparticle mediation. We restrict the scaling dimension d_u and the scalar
unparticle-photon-photon coupling by using the experimental upper limit of the
branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the
BRs of the other radiative decays by using the restrictions we get. We observe
that the measurements of upper limits of BRs of these decays ensure
considerable information for testing the possible signals coming from
unparticle physics


abstract:
  Mesoscopic conductance fluctuations in graphene samples at energies not very
close to the Dirac point are studied analytically. We demonstrate that the
conductance variance $<[\delta G]^2>$ is very sensitive to the elastic
scattering breaking the valley symmetry. In the absence of such scattering
(disorder potential smooth at atomic scales, trigonal warping negligible), the
variance $<[\delta G]^2 > = 4 < [\delta G]^2 >_\text{metal}$ is four times
greater than that in conventional metals, which is due to the two-fold valley
degeneracy. In the absence of intervalley scattering, but for strong
intravalley scattering and/or strong warping $<[\delta G]^2 > =2 < [\delta G]^2
>_\text{metal}$. Only in the limit of strong intervalley scattering $<[\delta
G]^2 > = < [\delta G]^2 >_\text{metal}$. Our theory explains recent numerical
results and can be used for comparison with existing experiments.


title:
Unitarity Constraints on Semi-hard Jet Production in Impact Parameter
  Space

abstract:
  The perturbative QCD formula for minijet production consitutes an important
ingredient in models describing the total cross section and multiparticle
production in hadron-hadron scattering at high energies. Using arguments based
on s-channel unitarity we set bounds on the minimum value of p_T for which the
leading twist minijet formula can be used. For large impact parameters where
correlations between partons appear to be small we find that the minimum value
of p_T should be greater than 2.5 GeV for LHC energies and greater than 3.5 GeV
for cosmic ray energies of about 50 TeV. We also argue that for collisions with
values of impact parameters typical for heavy particle production the values of
minimum p_T are likely to be considerably larger. We also analyze and quantify
the potential role of saturation effects in the gluon density. We find that
although saturation effects alone are not sufficient to restore unitarity, they
are likely to play an important role at LHC energies.


title:
Cosmological Perturbation Theory to second order for curvature, density,
  and gravity waves on FRW background; and the WMAP results of inhomogeneity
  and clustering in the early universe

abstract:
  The second order perturbation calculations for gravity wave and Einstein
equation for space time and matter are presented for the FRW metric
cosmological model. While exact equations are found, suitable approximations
are made to obtain definite results. In the gravity wave case the small
wavelength case allows nearly locally flat background for obtaining a fit to
the WMAP data. In the density and curvature case the FRW background is retained
for the length scale of WMAP. Clustering and inhomogeneity are understood. The
gravity wave ripples from Big Bang couple nonlinearly and redistribute the
modes to higher values of 'l' giving consistency with the WMAP results. The
order by order consistency of Einstein equations relate the second order
perturbations in the curvature and density and the wrinkles in spacetime caused
by the gravity wave modes reorganize these distributions. The radiation data of
WMAP gives the picture of a FRW spacetime deformed and wrinkled consistent with
matter distribution to one hundred thousandths parts variation.


title: Static strings in global AdS space and quark anti-quark potential

abstract:
  We investigate the finite temperature quark anti-quark problem in a compact
space $S^{n-1}\times S^1$ by considering static strings in global $AdS_{n+1}$
space with $n\ge 3$. For high temperatures we work in the black hole metric
where two possible solutions show up : the big black hole and the small black
hole. Using the AdS/CFT correspondence, we calculate the quark anti-quark
potential (free energy) as a function of the distance. We show that this
potential can be intrepeted as confining for the $AdS$ space and deconfining
for the big black hole. We find for the small black hole a confining limit for
the potential but this solution is instable following the Hawking-Page
criteria. Our results for the free energy reinforce the Witten interpretation
of the confinement/deconfinement transition as the dual of the well-known
Hawking-Page transition.


title: Cellularity of Cyclotomic Birman--Wenzl--Murakami algebras

abstract:
  We show that the cyclotomic Birman-Wenzl-Murakami algebras are cellular by
producing a cellular basis of affine tangle diagrams.


title: TOPICAL REVIEW: General relativistic boson stars

abstract:
  There is accumulating evidence that (fundamental) scalar fields may exist in
Nature. The gravitational collapse of such a boson cloud would lead to a boson
star (BS) as a new type of a compact object. Similarly as for white dwarfs and
neutron stars, there exists a limiting mass, below which a BS is stable against
complete gravitational collapse to a black hole. According to the form of the
self-interaction of the basic constituents and the spacetime symmetry, we can
distinguish mini-, axidilaton, soliton, charged, oscillating and rotating BSs.
Their compactness prevents a Newtonian approximation, however, modifications of
general relativity, as in the case of Jordan-Brans-Dicke theory as a low energy
limit of strings, would provide them with gravitational memory. In general, a
BS is a compact, completely regular configuration with structured layers due to
the anisotropy of scalar matter, an exponentially decreasing 'halo', a critical
mass inversely proportional to constituent mass, an effective radius, and a
large particle number. Due to the Heisenberg principle, there exists a
completely stable branch, and as a coherent state, it allows for rotating
solutions with quantised angular momentum. In this review, we concentrate on
the fascinating possibilities of detecting the various subtypes of (excited)
BSs: Possible signals include gravitational redshift and (micro-)lensing,
emission of gravitational waves, or, in the case of a giant BS, its dark matter
contribution to the rotation curves of galactic halos.


title:
The epic journey from Kepler's laws to Newton's law of universal
  gravitation revisited

abstract:
  In this article, we review the main results of Volume I of Newton's Principia
which relates Kepler's law of planets and universal gravitation. In order to
clarify the reasoning of Newton, elementary and simple proofs are given to
inspire earnest young students. All proofs are based on either the symmetry of
spheres or taking great advantage of Kepler's law of area which also reflects
the symmetry of centripedal forces.


title:
Ion collection by oblique surfaces of an object in a
  transversely-flowing strongly-magnetized plasma

abstract:
  The equations governing a collisionless obliquely-flowing plasma around an
ion-absorbing object in a strong magnetic field are shown to have an exact
analytic solution even for arbitrary (two-dimensional) object-shape, when
temperature is uniform, and diffusive transport can be ignored. The solution
has an extremely simple geometric embodiment. It shows that the ion collection
flux density to a convex body's surface depends only upon the orientation of
the surface, and provides the theoretical justification and calibration of
oblique `Mach-probes'. The exponential form of this exact solution helps
explain the approximate fit of this function to previous numerical solutions.


title:
Entanglement between a Two-level System and a Quantum Harmonic
  Oscillator

abstract:
  The entanglement between a Pauli-like two-level system and a quantum harmonic
oscillator enhanced by an interaction between them and a $\delta$-pulse
sequence is studied, with the decoherence due to their coupling with a
Markovian bath. Without the Markovian bath, the entanglement is enhanced to
maximum possible values. With the Markovian bath, the entanglement is enhanced
up to some time and then dissipated, with the system in thermal equilibrium
with the Markovian bath after a very long time. The time for achieving the
maximum entanglement shows discontinuous jumps over the parameters of
decoherence.


title: Comparison of objective functions for estimating linear-nonlinear models

abstract:
  This paper compares a family of methods for characterizing neural feature
selectivity with natural stimuli in the framework of the linear-nonlinear
model. In this model, the neural firing rate is a nonlinear function of a small
number of relevant stimulus components. The relevant stimulus dimensions can be
found by maximizing one of the family of objective functions, Renyi divergences
of different orders. We show that maximizing one of them, Renyi divergence of
order 2, is equivalent to least-square fitting of the linear-nonlinear model to
neural data. Next, we derive reconstruction errors in relevant dimensions found
by maximizing Renyi divergences of arbitrary order in the asymptotic limit of
large spike numbers. We find that the smallest rrors are obtained with Renyi
divergence of order 1, also known as Kullback-Leibler divergence. This
corresponds to finding relevant dimensions by maximizing mutual information. We
numerically test how these optimization schemes perform in the regime of low
signal-to-noise ratio (small number of spikes and increasing neural noise) for
model visual neurons. We find that optimization schemes based on either least
square fitting or information maximization perform well even when number of
spikes is small. Information maximization provides slightly, but significantly,
better reconstructions than least square fitting. This makes the problem of
finding relevant dimensions, together with the problem of lossy compression,
one of examples where information-theoretic measures are no more data limited
than those derived from least squares.


title: The Environment of Galaxies at Low Redshift

abstract:
  We compare environmental effects in two analogous samples of galaxies, one
from the Sloan Digital Sky Survey (SDSS) and the other from a semi-analytic
model (SAM) based on the Millennium Simulation (MS), to test to what extent
current SAMs of galaxy formation are reproducing environmental effects. We
estimate the large-scale environment of each galaxy using a Bayesian density
estimator based on distances to all ten nearest neighbors and compare
broad-band photometric properties of the two samples as a function of
environment. The feedbacks implemented in the semi-analytic model produce a
qualitatively correct galaxy population with similar environmental dependence
as that seen in SDSS galaxies. In detail, however, the colors of MS galaxies
exhibit an exaggerated dependence on environment: the field contains too many
blue galaxies while clusters contain too many red galaxies, compared to the
SDSS sample. We also find that the MS contains a population of highly
clustered, relatively faint red galaxies with velocity dispersions comparable
to their Hubble flow. Such high-density galaxies, if they exist, would be
overlooked in any low-redshift survey since their membership to a cluster
cannot be determined due to the "Fingers of God" effect.


title: The kernel and continuity ideals of homomorphisms from C_0(\Omega)

abstract:
  We give a description of the continuity ideals and the kernels of
homomorphisms from the algebras of continuous functions on locally compact
spaces into Banach algebras.


title: High-time Resolution Astrophysics and Pulsars

abstract:
  The discovery of pulsars in 1968 heralded an era where the temporal
characteristics of detectors had to be reassessed. Up to this point detector
integration times would normally be measured in minutes rather seconds and
definitely not on sub-second time scales. At the start of the 21st century
pulsar observations are still pushing the limits of detector telescope
capabilities. Flux variations on times scales less than 1 nsec have been
observed during giant radio pulses. Pulsar studies over the next 10 to 20 years
will require instruments with time resolutions down to microseconds and below,
high-quantum quantum efficiency, reasonable energy resolution and sensitive to
circular and linear polarisation of stochastic signals. This chapter is review
of temporally resolved optical observations of pulsars. It concludes with
estimates of the observability of pulsars with both existing telescopes and
into the ELT era.


title: Uncountable families of prime z-ideals in C_0(R)

abstract:
  Denote by $\continuum=2^{\aleph_0}$ the cardinal of continuum. We construct
an intriguing family $(P_\alpha: \alpha\in\continuum)$ of prime $z$-ideals in
$\C_0(\reals)$ with the following properties:
  If $f\in P_{i_0}$ for some $i_0\in\continuum$, then $f\in P_i$ for all but
finitely many $i\in \continuum$;
  $\bigcap_{i\neq i_0} P_i \nsubset P_{i_0}$ for each $\i_0\in \continuum$.
  We also construct a well-ordered increasing chain, as well as a well-ordered
decreasing chain, of order type $\kappa$ of prime $z$-ideals in $\C_0(\reals)$
for any ordinal $\kappa$ of cardinality $\continuum$.


title:
Effect of molecular and electronic structure on the light harvesting
  properties of dye sensitizers

abstract:
  The systematic trends in structural and electronic properties of perylene
diimide (PDI) derived dye molecules have been investigated by DFT calculations
based on projector augmented wave (PAW) method including gradient corrected
exchange-correlation effects. TDDFT calculations have been performed to study
the visible absorbance activity of these complexes. The effect of different
ligands and halogen atoms attached to PDI were studied to characterize the
light harvesting properties. The atomic size and electronegativity of the
halogen were observed to alter the relaxed molecular geometries which in turn
influenced the electronic behavior of the dye molecules. Ground state molecular
structure of isolated dye molecules studied in this work depends on both the
halogen atom and the carboxylic acid groups. DFT calculations revealed that the
carboxylic acid ligands did not play an important role in changing the
HOMO-LUMO gap of the sensitizer. However, they serve as anchor between the PDI
and substrate titania surface of the solar cell or photocatalyst. A
commercially available dye-sensitizer, ruthenium bipyridine (RuBpy), was also
studied for electronic and structural properties in order to make a comparison
with PDI derivatives for light harvesting properties. Results of this work
suggest that fluorinated, chlorinated, brominated, and iyodinated PDI compounds
can be useful as sensitizers in solar cells and in artificial photosynthesis.


title:
Uniform materials and the multiplicative decomposition of the
  deformation gradient in finite elasto-plasticity

abstract:
  In this work we analyze the relation between the multiplicative decomposition
$\mathbf F=\mathbf F^{e}\mathbf F^{p}$ of the deformation gradient as a product
of the elastic and plastic factors and the theory of uniform materials. We
prove that postulating such a decomposition is equivalent to having a uniform
material model with two configurations - total $\phi$ and the inelastic
$\phi_{1}$. We introduce strain tensors characterizing different types of
evolutions of the material and discuss the form of the internal energy and that
of the dissipative potential. The evolution equations are obtained for the
configurations $(\phi,\phi_{1})$ and the material metric $\mathbf g$.
  Finally the dissipative inequality for the materials of this type is
presented.It is shown that the conditions of positivity of the internal
dissipation terms related to the processes of plastic and metric evolution
provide the anisotropic yield criteria.


title: SUSY@LHC.CERN.CH

abstract:
  I discuss the program of work towards discoveries at the LHC, and I include
seeds for orientation and navigation in the parameter space given the foreseen
multitude of excesses at startup.


title:
A non-geodesic motion in the R^-1 theory of gravity tuned with
  observations

abstract:
  In the general picture of high order theories of gravity, recently, the R^-1
theory has been analyzed in two different frameworks. In this letter a third
context is added, considering an explicit coupling between the R^-1 function of
the Ricci scalar and the matter Lagrangian. The result is a non-geodesic motion
of test particles which, in principle, could be connected with Dark Matter and
Pioneer anomaly problems.


title: Climate Control Using Nuclear Energy

abstract:
  We examine implications of anthropogenic low pressure regions, - created by
injecting heat from nuclear reactors, into atmosphere. We suggest the
possibility that such artificially generated low pressure regions, near
hurricanes could disrupt their growth, path, and intensity. This method can
also create controlled tropical stroms, which lead to substantial rainfall in
arid areas, such as - (1)Sahara desert, (2) Australian interior desert, and (3)
Indian Thar desert. A simple vortex suction model is developed to study, effect
on atmospheric dynamics, by such a nuclear heat injection system.


title: A Self-Consistent NLTE-Spectra Synthesis Model of FeLoBAL QSOs

abstract:
  We present detailed radiative transfer spectral synthesis models for the Iron
Low Ionization Broad Absorption Line (FeLoBAL) active galactic nuclei (AGN)
FIRST J121442.3+280329 and ISO J005645.1-273816. Detailed NLTE spectral
synthesis with a spherically symmetric outflow reproduces the observed spectra
very well across a large wavelength range. While exact spherical symmetry is
probably not required, our model fits are of high quality and thus very large
covering fractions are strongly implied by our results. We constrain the
kinetic energy and mass in the ejecta and discuss their implications on the
accretion rate. Our results support the idea that FeLoBALs may be an
evolutionary stage in the development of more ``ordinary'' QSOs.


title:
Low energy expansion of the four-particle genus-one amplitude in type II
  superstring theory

abstract:
  A diagrammatic expansion of coefficients in the low-momentum expansion of the
genus-one four-particle amplitude in type II superstring theory is developed.
This is applied to determine coefficients up to order s^6R^4 (where s is a
Mandelstam invariant and R^4 the linearized super-curvature), and partial
results are obtained beyond that order. This involves integrating powers of the
scalar propagator on a toroidal world-sheet, as well as integrating over the
modulus of the torus. At any given order in s the coefficients of these terms
are given by rational numbers multiplying multiple zeta values (or
Euler--Zagier sums) that, up to the order studied here, reduce to products of
Riemann zeta values. We are careful to disentangle the analytic pieces from
logarithmic threshold terms, which involves a discussion of the conditions
imposed by unitarity. We further consider the compactification of the amplitude
on a circle of radius r, which results in a plethora of terms that are
power-behaved in r. These coefficients provide boundary `data' that must be
matched by any non-perturbative expression for the low-energy expansion of the
four-graviton amplitude.
  The paper includes an appendix by Don Zagier.


title:
Chemical Potential and the Nature of the Dark Energy: The case of
  phantom

abstract:
  The influence of a possible non zero chemical potential $\mu$ on the nature
of dark energy is investigated by assuming that the dark energy is a
relativistic perfect simple fluid obeying the equation of state (EoS),
$p=\omega \rho$ ($\omega <0, constant$). The entropy condition, $S \geq 0$,
implies that the possible values of $\omega$ are heavily dependent on the
magnitude, as well as on the sign of the chemical potential. For $\mu >0$, the
$\omega$-parameter must be greater than -1 (vacuum is forbidden) while for $\mu
< 0$ not only the vacuum but even a phantomlike behavior ($\omega <-1$) is
allowed. In any case, the ratio between the chemical potential and temperature
remains constant, that is, $\mu/T=\mu_0/T_0$. Assuming that the dark energy
constituents have either a bosonic or fermionic nature, the general form of the
spectrum is also proposed. For bosons $\mu$ is always negative and the extended
Wien's law allows only a dark component with $\omega < -1/2$ which includes
vacuum and the phantomlike cases. The same happens in the fermionic branch for
$\mu <0$. However, fermionic particles with $\mu >0$ are permmited only if $-1
< \omega < -1/2$. The thermodynamics and statistical arguments constrain the
EoS parameter to be $\omega < -1/2$, a result surprisingly close to the maximal
value required to accelerate a FRW type universe dominated by matter and dark
energy ($\omega \lesssim -10/21$).


title: Nonsplitting in Kirchberg's ideal-related KK-theory

abstract:
  A universal coefficient theorem in the setting of Kirchberg's ideal-related
KK-theory was obtained in the fundamental case of a C*-algebra with one
specified ideal by Bonkat and proved there to split, unnaturally, under certain
conditions. Employing certain K-theoretical information derivable from the
given operator algebras in a way introduced here, we shall demonstrate that
Bonkat's UCT does not split in general. Related methods lead to information on
the complexity of the K-theory which must be used to classify *-isomorphisms
for purely infinite C*-algebras with one non-trivial ideal.


title: Propagator of the lattice domain wall fermion and the staggered fermion

abstract:
  The propagator of the domain wall fermion is calculated from the gauge
configurations of the RBC-UKQCD collaborations with 2+1 dynamical flavors of
$16^3\times 32\times 16$ lattice. The ambiguity of the phase is adjusted such
that the overlap of the solution of the conjugate gradient method and the plane
wave at the source becomes real. The mass function becomes close to those of
Kogut-Susskind fermion, but no anomalous behavior for $u/d$-quark mass and
s-quark mass ratio close to 0.75 appears.


title: Loop Quantum Theory Applied to Biology and Nonlinear Whole Biology

abstract:
  The loop quantum theory, which constitutes a very small discontinuous space,
as new method is applied to biology. The model of protein folding and lungs is
proposed. In the model, some known results are used, and four approximate
conclusions are obtained: their structures are quantized, their space regions
are finite, various singularities correspond to folding and crossed points, and
different types of catastrophe exist. Further, based on the inseparability and
correlativity of the biological systems, the nonlinear whole biology is
proposed, and four basic hypotheses are formed. It may unify reductionism and
holism, structuralism and functionalism. Finally, the medical meaning of the
theory is discussed briefly.


title: Nonparametric sequential prediction of time series

abstract:
  Time series prediction covers a vast field of every-day statistical
applications in medical, environmental and economic domains. In this paper we
develop nonparametric prediction strategies based on the combination of a set
of 'experts' and show the universal consistency of these strategies under a
minimum of conditions. We perform an in-depth analysis of real-world data sets
and show that these nonparametric strategies are more flexible, faster and
generally outperform ARMA methods in terms of normalized cumulative prediction
error.


title:
Fiber based source of photon pairs at telecom band with high temporal
  coherence and brightness for quantum information processing

abstract:
  We experimentally demonstrate a bright pulsed source of correlated photon
pairs at 1550 nm telecom band by pumping 300 m dispersion shifted fiber with a
4 ps pulse train. We investigate the coherence property of the source by
measuring the second order intensity correlation function $g^{(2)}$ of
individual signal (idler) photons. A preliminary Hong-Ou-Mandel type two-photon
interference experiment with two such sources confirms the high temporal and
spatial coherence of the source. The source is suitable for multi-photon
quantum interference of independent sources, required in quantum information
processing.


title: Euler Numbers and polynomials associated with zeta functions

abstract:
  In this paper we give some interesting identities between Euler numbers and
zeta functions. Finally we will give the new values of Euler zeta function at
positive even integers.


title: Properties of Expectations of Functions of Martingale Diffusions

abstract:
  Given a real valued and time-inhomogeneous martingale diffusion X, we
investigate the properties of functions defined by the conditional expectation
f(t,X_t)=E[g(X_T)|F_t]. We show that whenever g is monotonic or Lipschitz
continuous then f(t,x) will also be monotonic or Lipschitz continuous in x. If
g is convex then f(t,x) will be convex in x and decreasing in t. We also define
the marginal support of a process and show that it almost surely contains the
paths of the process. Although f need not be jointly continuous, we show that
it will be continuous on the marginal support of X. We prove these results for
a generalization of diffusion processes that we call `almost-continuous
diffusions', and includes all continuous and strong Markov processes.


title: Attractor Solutions in Lorentz Violating Scalar-Vector-Tensor Theory

abstract:
  We investigate properties of attractors for scalar field in the Lorentz
violating scalar-vector-tensor theory of gravity. In this framework, both the
effective coupling and potential functions determine the stabilities of the
fixed points. In the model, we consider the constants of slope of the effective
coupling and potential functions which lead to the quadratic effective coupling
vector with the (inverse) power-law potential. For the case of purely scalar
field, there are only two stable attractor solutions in the inflationary
scenario. In the presence of a barotropic fluid, the fluid dominated solution
is absent. We find two scaling solutions: the kinetic scaling solution and the
scalar field scaling solutions. We show the stable attractors in regions of
($\gamma$, $\xi$) parameter space and in phase plane plot for different
qualitative evolutions. From the standard nucleosynthesis, we derive the
constraints for the value of the coupling parameter.


title: Explicit fibrant replacement for discrete G-spectra

abstract:
  If C is the model category of simplicial presheaves on a site with enough
points, with fibrations equal to the global fibrations, then it is well-known
that the fibrant objects are, in general, mysterious. Thus, it is not
surprising that, when G is a profinite group, the fibrant objects in the model
category of discrete G-spectra are also difficult to get a handle on. However,
with simplicial presheaves, it is possible to construct an explicit fibrant
model for an object in C, under certain finiteness conditions. Similarly, in
this paper, we show that if G has finite virtual cohomological dimension and X
is a discrete G-spectrum, then there is an explicit fibrant model for X. Also,
we give several applications of this concrete model related to closed subgroups
of G.


title: Minimal gauge inflation

abstract:
  We consider a gauge inflation model in the simplest orbifold M4 x S1/Z2 with
the minimal non-Abelian SU(2) hidden sector gauge symmetry. The inflaton
potential is fully radiatively generated solely by gauge self-interactions.
Following the virtue of gauge inflation idea, the inflaton, a part of the five
dimensional gauge boson, is automatically protected by the gauge symmetry and
its potential is stable against quantum corrections. We show that the model
perfectly fits the recent cosmological observations, including the recent WMAP
5-year data, in a wide range of the model parameters. In the perturbative
regime of gauge interactions (g_{4D} <= 1/(2pi R M_P)) with the moderately
compactified radius (10 <= R M_P <= 100) the anticipated magnitude of the
curvature perturbation power spectrum and the value of the corresponding
spectral index are in perfect agreement with the recent observations. The model
also predicts a large fraction of the gravitational waves, negligible
non-Gaussianity, and high enough reheating temperature.


title:
Bright Giant Pulses from the Crab Nebula Pulsar: Statistical Properties,
  Pulse Broadening and Scattering due to the Nebula

abstract:
  We report observations of Crab giant pulses made with the Australia Telescope
Compact Array and a baseband recorder system, made simultaneously at two
frequencies, 1300 and 1470 MHz. These observations were sensitive to pulses
with amplitudes \ga 3 kJy and widths \ga 0.5 $\mu$s. Our analysis led to the
detection of more than 700 such bright giant pulses over 3 hours, and using
this large sample we investigate their amplitude, width, arrival time and
energy distributions. The brightest pulse detected in our data has a peak
amplitude of $\sim$ 45 kJy and a width of $\sim$ 0.5 $\mu$s, and therefore an
inferred brightness temperature of $\sim 10^{35}$ K. The duration of
giant-pulse emission is typically $\sim$1 $\mu$s, however it can also be as
long as 10 $\mu$s. The pulse shape at a high time resolution (128 ns) shows
rich diversity and complexity in structure and is marked by an unusually low
degree of scattering. We discuss possible implications for scattering due to
the nebula, and for underlying structures and electron densities.


title: Longitudinal and transverse components of a vector field

abstract:
  A unified account, from a pedagogical perspective, is given of the
longitudinal and transverse projective delta functions proposed by Belinfante
and of their relation to the Helmholtz theorem for the decomposition of a
three-vector field into its longitudinal and transverse components. It is
argued that the results are applicable to fields that are time-dependent as
well as fields that are time-independent.


title: Astronomical Image Subtraction by Cross-Convolution

abstract:
  In recent years, there has been a proliferation of wide-field sky surveys to
search for a variety of transient objects. Using relatively short focal
lengths, the optics of these systems produce undersampled stellar images often
marred by a variety of aberrations. As participants in such activities, we have
developed a new algorithm for image subtraction that no longer requires high
quality reference images for comparison. The computational efficiency is
comparable with similar procedures currently in use. The general technique is
cross-convolution: two convolution kernels are generated to make a test image
and a reference image separately transform to match as closely as possible. In
analogy to the optimization technique for generating smoothing splines, the
inclusion of an RMS width penalty term constrains the diffusion of stellar
images. In addition, by evaluating the convolution kernels on uniformly spaced
subimages across the total area, these routines can accomodate point spread
functions that vary considerably across the focal plane.


title: The Physical World as a Virtual Reality

abstract:
  This paper explores the idea that the universe is a virtual reality created
by information processing, and relates this strange idea to the findings of
modern physics about the physical world. The virtual reality concept is
familiar to us from online worlds, but our world as a virtual reality is
usually a subject for science fiction rather than science. Yet logically the
world could be an information simulation running on a multi-dimensional
space-time screen. Indeed, if the essence of the universe is information,
matter, charge, energy and movement could be aspects of information, and the
many conservation laws could be a single law of information conservation. If
the universe were a virtual reality, its creation at the big bang would no
longer be paradoxical, as every virtual system must be booted up. It is
suggested that whether the world is an objective reality or a virtual reality
is a matter for science to resolve. Modern information science can suggest how
core physical properties like space, time, light, matter and movement could
derive from information processing. Such an approach could reconcile relativity
and quantum theories, with the former being how information processing creates
space-time, and the latter how it creates energy and matter.


title: Magnetophoresis of Flexible DNA-based Dumbbell Structures

abstract:
  Controlled movement and manipulation of magnetic micro and nanostructures
using magnetic forces can give rise to important applications in biomedecine,
diagnostics and immunology. We report controlled magnetophoresis and
stretching, in aqueous solution, of a DNA-based dumbbell structure containing
magnetic and diamagnetic microspheres. The velocity and stretching of the
dumbbell were experimentally measured and correlated with a theoretical model
based on the forces acting on individual magnetic beads or the entire dumbbell
structures. The results show that precise and predictable manipulation of
dumbbell structures is achievable and can potentially be applied to
immunomagnetic cell separators.


title: Hyperelliptic plane curves of type (d,d-2)

abstract:
  In a previous paper, we classified and constructed all rational plane curves
of type (d,d-2). In this paper, we generalize these results to irreducible
plane curves of type (d,d-2) with positive genus.


title:
Sum Rate Maximization using Linear Precoding and Decoding in the
  Multiuser MIMO Downlink

abstract:
  We propose an algorithm to maximize the instantaneous sum data rate
transmitted by a base station in the downlink of a multiuser multiple-input,
multiple-output system. The transmitter and the receivers may each be equipped
with multiple antennas and each user may receive more than one data stream. We
show that maximizing the sum rate is closely linked to minimizing the product
of mean squared errors (PMSE). The algorithm employs an uplink/downlink duality
to iteratively design transmit-receive linear precoders, decoders, and power
allocations that minimize the PMSE for all data streams under a sum power
constraint. Numerical simulations illustrate the effectiveness of the algorithm
and support the use of the PMSE criterion in maximizing the overall
instantaneous data rate.


title: Exactness of Belief Propagation for Some Graphical Models with Loops

abstract:
  It is well known that an arbitrary graphical model of statistical inference
defined on a tree, i.e. on a graph without loops, is solved exactly and
efficiently by an iterative Belief Propagation (BP) algorithm convergent to
unique minimum of the so-called Bethe free energy functional. For a general
graphical model on a loopy graph the functional may show multiple minima, the
iterative BP algorithm may converge to one of the minima or may not converge at
all, and the global minimum of the Bethe free energy functional is not
guaranteed to correspond to the optimal Maximum-Likelihood (ML) solution in the
zero-temperature limit. However, there are exceptions to this general rule,
discussed in \cite{05KW} and \cite{08BSS} in two different contexts, where
zero-temperature version of the BP algorithm finds ML solution for special
models on graphs with loops. These two models share a key feature: their ML
solutions can be found by an efficient Linear Programming (LP) algorithm with a
Totally-Uni-Modular (TUM) matrix of constraints. Generalizing the two models we
consider a class of graphical models reducible in the zero temperature limit to
LP with TUM constraints. Assuming that a gedanken algorithm, g-BP, funding the
global minimum of the Bethe free energy is available we show that in the limit
of zero temperature g-BP outputs the ML solution. Our consideration is based on
equivalence established between gapless Linear Programming (LP) relaxation of
the graphical model in the $T\to 0$ limit and respective LP version of the
Bethe-Free energy minimization.

categories: cond-mat.stat-mech cond-mat.other cs.AI cs.IT math.IT


title: Wavefunction preparation and resampling using a quantum computer

abstract:
  We present an algorithm that prepares multidimensional Gaussian wavefunctions
on qubit arrays and an application of such wavefunctions to multidimensional
resampling, a technique useful in quantum digital simulation.


title: Secular evolution of disk galaxies

abstract:
  Galaxy disks evolve through angular momentum transfers between
sub-components, like gas, stars, or dark matter halos, through non
axi-symmetric instabilities. The speed of this evolution is boosted in presence
of a large fraction of cold and dissipative gas component. When the visible
matter dominates over the whole disk, angular momentum is exchanged between gas
and stars only. The gas is driven towards the center by bars, stalled
transiently in resonance rings, and driven further by embedded bars, which it
contributes to destroy. From a small-scale molecular torus, the gas can then
inflow from viscous torques, dynamical friction, or m=1 perturbations.
  In the weakened bar phases, multiple-speed spiral patterns can develop and
help the galaxy to accrete external gas flowing from cosmic filaments. The
various phases of secular evolution are illustrated by numerical simulations.


title: Not T-parity but C-parity

abstract:
  We revisit the Littlest Higgs model with $T$-parity, and discover a $Z_2$
symmetry on collective symmetry. It is dubbed collective parity
($\EuScript{C}$-parity). We demonstrate that $T$-parity is consistent with
$\EuScript{C}$-parity. We further investigate the origin of the collective
symmetry in the context of composite Higgs and find a new path to the UV
complete theory of the model. In addition, we demonstrate that $T$-parity
violating processes naturally take place.


title: Near-ideal model selection by $\ell_1$ minimization

abstract:
  We consider the fundamental problem of estimating the mean of a vector
$y=X\beta+z$, where $X$ is an $n\times p$ design matrix in which one can have
far more variables than observations, and $z$ is a stochastic error term--the
so-called "$p>n$" setup. When $\beta$ is sparse, or, more generally, when there
is a sparse subset of covariates providing a close approximation to the unknown
mean vector, we ask whether or not it is possible to accurately estimate
$X\beta$ using a computationally tractable algorithm. We show that, in a
surprisingly wide range of situations, the lasso happens to nearly select the
best subset of variables. Quantitatively speaking, we prove that solving a
simple quadratic program achieves a squared error within a logarithmic factor
of the ideal mean squared error that one would achieve with an oracle supplying
perfect information about which variables should and should not be included in
the model. Interestingly, our results describe the average performance of the
lasso; that is, the performance one can expect in an vast majority of cases
where $X\beta$ is a sparse or nearly sparse superposition of variables, but not
in all cases. Our results are nonasymptotic and widely applicable, since they
simply require that pairs of predictor variables are not too collinear.


title:
Two point third order correlation functions for quasi-geostrophic
  turbulence: Kolmogorov-Landau approach

abstract:
  We use the more intuitive approach due to Kolmogorov (and subsequently,
Landau in his text on fluid dynamics) to calculate some third-order structure
functions for quasi-geostrophic turbulence for the forward cascade of
pseudo-potential enstrophy and the inverse energy cascade in quasi-geostrophic
turbulence.


title:
On scaling laws in turbulent magnetohydrodynamic Rayleigh-Benard
  convection

abstract:
  We invoke the concepts of magnetic boundary layer and magnetic Rayleigh
number and use the magnetic energy dissipation rates in the bulk and the
boundary layers to derive some scaling laws expressing how Nusselt number
depends on magnetic Rayleigh number, Prandtl number and magnetic Prandtl number
for the simple case of turbulent magnetohydrodynamic Rayleigh-Benard convection
in the presence of uniform vertical magnetic field.


title: Infall and Outflow of Molecular Gas in Sgr B2

abstract:
  Observations of two H$_2$CO ($3_{03}-2_{02}$ and $3_{21}-2_{20}$) lines and
continuum emission at 1.3 mm towards Sgr B2(N) and Sgr B2(M) have been carried
out with the SMA. The mosaic maps of Sgr B2(N) and Sgr B2(M) in both continuum
and lines show a complex distribution of dust and molecular gas in both clumps
and filaments surrounding the compact star formation cores. We have observed a
decelerating outflow originated from the Sgr B2(M) core, showing that both the
red-shifted and blue-shifted outflow components have a common terminal
velocity. This terminal velocity is 58$\pm$2 km s$^{-1}$. It provides an
excellent method in determination of the systematic velocity of the molecular
cloud. The SMA observations have also shown that a large fraction of absorption
against the two continuum cores is red-shifted with respect to the systematic
velocities of Sgr B2(N) and Sgr B2(M), respectively, suggesting that the
majority of the dense molecular gas is flowing into the two major cores where
massive stars have been formed. We have solved the radiative transfer in a
multi-level system with LVG approximation. The observed H$_2$CO line
intensities and their ratios can be adequately fitted with this model for the
most of the gas components. However, the line intensities between the higher
energy level transition H$_2$CO ($3_{21}-2_{20}$) and the lower energy level
transition H$_2$CO ($3_{03}-2_{02}$) is reversed in the red-shifted outflow
region of Sgr B2(M), suggesting the presence of inversion in population between
the ground levels in the two K ladders (K$_{-1}$= 0 and 2). The possibility of
weak maser processes for the H$_2$CO emission in Sgr B2(M) is discussed.


title:
Church, Cardinal and Ordinal Representations of Integers and Kolmogorov
  complexity

abstract:
  We consider classical representations of integers: Church's function
iterators, cardinal equivalence classes of sets, ordinal equivalence classes of
totally ordered sets. Since programs do not work on abstract entities and
require formal representations of objects, we effectivize these abstract
notions in order to allow them to be computed by programs. To any such
effectivized representation is then associated a notion of Kolmogorov
complexity. We prove that these Kolmogorov complexities form a strict hierarchy
which coincides with that obtained by relativization to jump oracles and/or
allowance of infinite computations.


title:
Refinment of the "up to a constant" ordering using contructive
  co-immunity and alike. Application to the Min/Max hierarchy of Kolmogorov
  complexities

abstract:
  We introduce orderings between total functions f,g: N -> N which refine the
pointwise "up to a constant" ordering <=cte and also insure that f(x) is often
much less thang(x). With such orderings, we prove a strong hierarchy theorem
for Kolmogorov complexities obtained with jump oracles and/or Max or Min of
partial recursive functions. We introduce a notion of second order conditional
Kolmogorov complexity which yields a uniform bound for the "up to a constant"
comparisons involved in the hierarchy theorem.


title: Kolmogorov complexities Kmax, Kmin on computable partially ordered sets

abstract:
  We introduce a machine free mathematical framework to get a natural
formalization of some general notions of infinite computation in the context of
Kolmogorov complexity. Namely, the classes Max^{X\to D}_{PR} and Max^{X\to
D}_{Rec} of functions X \to D which are pointwise maximum of partial or total
computable sequences of functions where D = (D,<) is some computable partially
ordered set. The enumeration theorem and the invariance theorem always hold for
Max^{X\to D}_{PR}, leading to a variant KD;max of Kolmogorov complexity. We
characterize the orders D such that the enumeration theorem (resp. the
invariance theorem) also holds for Max^{X\to D}_{Rec} . It turns out that
Max^{X\to D}_{Rec} may satisfy the invariance theorem but not the enumeration
theorem. Also, when Max^{X\to D}_{Rec} satisfies the invariance theorem then
the Kolmogorov complexities associated to Max^{X\to D}_{Rec} and Max^{X\to
D}_{PR} are equal (up to a constant).
  Letting K^D_{min} = K^{D^{rev}}_{max}, where D^{rev} is the reverse order, we
prove that either K^D_{min} =_{ct} K^D_{max} =_{ct} K^D (=_{ct} is equality up
to a constant) or K^D_{min}, K^D_{max} are <=_{ct} incomparable and <_{ct} K^D
and >_{ct} K^{0',D}. We characterize the orders leading to each case. We also
show that K^D_{min}, K^D_{max} cannot be both much smaller than K^D at any
point.
  These results are proved in a more general setting with two orders on D, one
extending the other.


title: The price of certainty: "waterslide curves" and the gap to capacity

abstract:
  The classical problem of reliable point-to-point digital communication is to
achieve a low probability of error while keeping the rate high and the total
power consumption small. Traditional information-theoretic analysis uses
`waterfall' curves to convey the revolutionary idea that unboundedly low
probabilities of bit-error are attainable using only finite transmit power.
However, practitioners have long observed that the decoder complexity, and
hence the total power consumption, goes up when attempting to use sophisticated
codes that operate close to the waterfall curve.
  This paper gives an explicit model for power consumption at an idealized
decoder that allows for extreme parallelism in implementation. The decoder
architecture is in the spirit of message passing and iterative decoding for
sparse-graph codes. Generalized sphere-packing arguments are used to derive
lower bounds on the decoding power needed for any possible code given only the
gap from the Shannon limit and the desired probability of error. As the gap
goes to zero, the energy per bit spent in decoding is shown to go to infinity.
This suggests that to optimize total power, the transmitter should operate at a
power that is strictly above the minimum demanded by the Shannon capacity.
  The lower bound is plotted to show an unavoidable tradeoff between the
average bit-error probability and the total power used in transmission and
decoding. In the spirit of conventional waterfall curves, we call these
`waterslide' curves.


title: Set theoretical Representations of Integers, I

abstract:
  We reconsider some classical natural semantics of integers (namely iterators
of functions, cardinals of sets, index of equivalence relations), in the
perspective of Kolmogorov complexity. To each such semantics one can attach a
simple representation of integers that we suitably effectivize in order to
develop an associated Kolmogorov theory. Such effectivizations are particular
instances of a general notion of "self-enumerated system" that we introduce in
this paper. Our main result asserts that, with such effectivizations,
Kolmogorov theory allows to quantitatively distinguish the underlying
semantics. We characterize the families obtained by such effectivizations and
prove that the associated Kolmogorov complexities constitute a hierarchy which
coincides with that of Kolmogorov complexities defined via jump oracles and/or
infinite computations. This contrasts with the well-known fact that usual
Kolmogorov complexity does not depend (up to a constant) on the chosen
arithmetic representation of integers, let it be in any base unary, binary et
so on. Also, in a conceptual point of view, our result can be seen as a mean to
measure the degree of abstraction of these diverse semantics.


title: Kolmogorov complexity in perspective

abstract:
  We survey the diverse approaches to the notion of information content: from
Shannon entropy to Kolmogorov complexity. The main applications of Kolmogorov
complexity are presented namely, the mathematical notion of randomness (which
goes back to the 60's with the work of Martin-Lof, Schnorr, Chaitin, Levin),
and classification, which is a recent idea with provocative implementation by
Vitanyi and Cilibrasi.


title:
Comparative study of the radius of sensitivity of the optical model
  potentials for $^6$Li+$^{58,64}$Ni and $^{16}$O+$^{58,64}$Ni

abstract:
  Radii of sensitivity were estimated for the $^{6}$Li+$^{58,64}$Ni system at
energies near the Coulomb barrier. For comparison purposes, such radii were
also estimated for stable $^{16}$O scattered from same target isotopes. The
elastic scattering data were analysed with folded real potential generated from
DDM3Y nucleon-nucleon interaction and an imaginary potential of volume
Woods-Saxon form. The most sensitive radii for $^{16}$O+$^{58,64}$Ni system are
found to be energy independent and close to the strong absorption radius. For
$^{6}$Li projectile, unlike its strongly bound counterpart, the crossing radius
increases with decreasing energy. However, no two crossing situation has been
observed for both $^{6}$Li+$^{58,64}$Ni and $^{16}$O+$^{58,64}$Ni systems at
the top of the barrier.


title: Localization at threshold in noncommutative space

abstract:
  The ground state energy of a scale symmetric system usually does not possess
any lower bound, thus making the system quantum mechanically unstable.
Self-adjointness and renormalization techniques usually provide the system a
scale and thus making the ground state bounded from below. We on the other hand
use noncommutative quantum mechanics and exploit the noncommutative parameter
\Theta as a scale for a scale symmetric system. The resulting Hamiltonian for
the system then allows an unusual bound state at the threshold of the energy,
E=0. Apart from the Hamiltonian \hat{H} we also compute the other two
generators of the so(2,1) algebra, the dilation \hat{D} and the conformal
generator \hat{K} in the noncommutative space. The so(2,1) algebra is not
closed in the noncommutative space, but the limit \Theta\to 0 smoothly goes to
the so(2,1) algebra restoring the conformal symmetry. We also discuss the
system for large noncommutative parameter.


title:
Spatiotemporal Noise Triggering Infiltrative Tumor Growth under Immune
  Surveillance

abstract:
  A spatiotemporal noise is assumed to reflect the environmental fluctuation in
a spatially extended tumor system. We introduce firstly the structure factor to
reveal the invasive tumor growth quantitatively. The homogenous environment can
lead to an expansive growth of the tumor cells, while the inhomogenous
environment underlies an infiltrative growth. The different responses of above
two cases are separated by a characteristic critical intensity of the
spatiotemporal noise. Theoretical and numerical results present a close
annotation to the clinical images.


title:
Signature of deconfinement with spin down compression in cooling hybrid
  stars

abstract:
  The thermal evolution of neutron stars is coupled to their spin down and the
resulting changes in structure and chemical composition. This coupling
correlates stellar surface temperatures with rotational state as well as time.
We report an extensive investigation of the coupling between spin down and
cooling for hybrid stars which undergo a phase transition to deconfined quark
matter at the high densities present in stars at low rotation frequencies. The
thermal balance of neutron stars is re-analyzed to incorporate phase
transitions and the related latent heat self-consistently, and numerical
calculations are undertaken to simultaneously evolve the stellar structure and
temperature distribution. We find that the changes in stellar structure and
chemical composition with the introduction of a pure quark matter phase in the
core delay the cooling and produce a period of increasing surface temperature
for strongly superfluid stars of strong and intermediate magnetic field
strength. The latent heat of deconfinement is found to reinforce this signature
if quark matter is superfluid and it can dominate the thermal balance during
the formation of a pure quark matter core. At other times it is less important
and does not significantly change the thermal evolution.


title: Matrix Hamiltonians with an algebraic guarantee of unbroken PT-symmetry

abstract:
  Quantum bound-state energies are assumed generated by PT-symmetric
Hamiltonians H where P is, typically, parity. It is known that their spectrum
only remains real and observable (i.e., in the language of physics, the
PT-symmetry remains unbroken) inside a certain domain D of couplings. We show
that the boundary of this domain (i.e., certain stability and observability
horizon formed by the Kato's exceptional points) remains algebraic (i.e., we
determine it by closed formulae) for a certain toy-model family of
N-dimensional anharmonic-oscillator-related matrix Hamiltonians with dimensions
between N=2 and N=11.


title: Color Superconductivity and Tsallis Statistics

abstract:
  The generalized non-extensive statistics proposed by Tsallis have been
successfully utilized in many systems where long range interactions are
present. For high density quark matter an attractive long range interaction
arising from single gluon exchange suggests the formation of a diquark
condensate. We study the effects on this color superconducting phase for two
quark flavors due to a change to Tsallis statistics. By numerically solving the
gap equation we obtain a generalization of the universality condition,
$\frac{2\phi_{0}}{T_{C}}\approx 3.52$ and determine the temperature dependence
of the gap. For the Tsallis parameter $q\approx 1$ the specific heat is
exponential becoming more linear as q increases. This suggests that for larger
values of q s-wave color superconductors behave like high $T_c$ superconductors
rather than weak superconductors.