title:
Lower ground state due to counter-rotating wave interaction in trapped
  ion system

abstract:
  We consider a single ion confined in a trap under radiation of two traveling
waves of lasers. In the strong-excitation regime and without the restriction of
Lamb-Dicke limit, the Hamiltonian of the system is similar to a driving
Jaynes-Cummings model without rotating wave approximation (RWA). The approach
we developed enables us to present a complete eigensolutions, which makes it
available to compare with the solutions under the RWA. We find that, the ground
state in our non-RWA solution is energically lower than the counterpart under
the RWA. If we have the ion in the ground state, it is equivalent to a spin
dependent force on the trapped ion. Discussion is made for the difference
between the solutions with and without the RWA, and for the relevant
experimental test, as well as for the possible application in quantum
information processing.


title:
Strained single-crystal Al2O3 grown layer-by-layer on Nb (110) thin
  films

abstract:
  We report on the layer-by-layer growth of single-crystal Al2O3 thin-films on
Nb (110). Single-crystal Nb films are first prepared on A-plane sapphire,
followed by the evaporation of Al in an O2 background. The first stages of
Al2O3 growth are layer-by-layer with hexagonal symmetry. Electron and x-ray
diffraction measurements indicate the Al2O3 initially grows clamped to the Nb
lattice with a tensile strain near 10%. This strain relaxes with further
deposition, and beyond about 5 nm we observe the onset of island growth.
Despite the asymmetric misfit between the Al2O3 film and the Nb under-layer,
the observed strain is surprisingly isotropic.


title:
Quasi-quartet crystal electric field ground state in a tetragonal
  CeAg$_2$Ge$_2$ single crystal

abstract:
  We have successfully grown the single crystals of CeAg$_2$Ge$_2$, for the
first time, by flux method and studied the anisotropic physical properties by
measuring the electrical resistivity, magnetic susceptibility and specific
heat. We found that CeAg$_2$Ge$_2$ undergoes an antiferromagnetic transition at
$T_{\rm N}$ = 4.6 K. The electrical resistivity and susceptibility data reveal
strong anisotropic magnetic properties. The magnetization measured at $T$ = 2 K
exhibited two metamagnetic transitions at $H_{\rm m1}$ = 31 kOe and $H_{\rm
m2}$ = 44.7 kOe, for $H \parallel$ [100] with a saturation magnetization of 1.6
$\mu_{\rm B}$/Ce. The crystalline electric field (CEF) analysis of the inverse
susceptibility data reveals that the ground state and the first excited states
of CeAg$_2$Ge$_2$ are closely spaced indicating a quasi-quartet ground state.
The specific heat data lend further support to the presence of closely spaced
energy levels.


title: Strong Phase and $D^0-D^0bar$ mixing at BES-III

abstract:
  Most recently, both BaBar and Belle experiments found evidences of neutral
$D$ mixing. In this paper, we discuss the constraints on the strong phase
difference in $D^0 \to K\pi$ decay from the measurements of the mixing
parameters, $y^\prime$, $y_{CP}$ and $x$ at the $B$ factories. The sensitivity
of the measurement of the mixing parameter $y$ is estimated in BES-III
experiment at $\psi(3770)$ peak. We also make an estimate on the measurements
of the mixing rate $R_M$. Finally, the sensitivity of the strong phase
difference at BES-III are obtained by using data near the $D\bar{D}$ threshold
with CP tag technique at BES-III experiment.


title: Meta-Stable Brane Configuration of Product Gauge Groups

abstract:
  Starting from the N=1 SU(N_c) x SU(N_c') gauge theory with fundamental and
bifundamental flavors, we apply the Seiberg dual to the first gauge group and
obtain the N=1 dual gauge theory with dual matters including the gauge
singlets. By analyzing the F-term equations of the superpotential, we describe
the intersecting type IIA brane configuration for the meta-stable
nonsupersymmetric vacua of this gauge theory. By introducing an orientifold
6-plane, we generalize to the case for N=1 SU(N_c) x SO(N_c') gauge theory with
fundamental and bifundamental flavors. Finally, the N=1 SU(N_c) x Sp(N_c')
gauge theory with matters is also described very briefly.


title: Spinor dipolar Bose-Einstein condensates; Classical spin approach

abstract:
  Magnetic dipole-dipole interaction dominated Bose-Einstein condensates are
discussed under spinful situations. We treat the spin degrees of freedom as a
classical spin vector, approaching from large spin limit to obtain an effective
minimal Hamiltonian; a version extended from a non-linear sigma model. By
solving the Gross-Pitaevskii equation we find several novel spin textures where
the mass density and spin density are strongly coupled, depending upon trap
geometries due to the long-range and anisotropic natures of the dipole-dipole
interaction.


title:
Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave
  Solid-State Resonator of the Nonautonomous Phaser Generator

abstract:
  The microwave phonon stimulated emission (SE) has been experimentally and
numerically investigated in a nonautonomous microwave acoustic quantum
generator, called also microwave phonon laser or phaser (see previous works
arXiv:cond-mat/0303188 ; arXiv:cond-mat/0402640 ; arXiv:nlin.CG/0703050)
Phenomena of branching and long-time refractority (absence of the reaction on
the external pulses) for deterministic chaotic and regular processes of SE were
observed in experiments with various levels of electromagnetic pumping. At the
pumping level growth, the clearly depined increasing of the number of
coexisting SE states has been observed both in real physical experiments and in
computer simulations. This confirms the analytical estimations of the branching
density in the phase space. The nature of the refractority of SE pulses is
closely connected with the pointed branching and reflects the crises of strange
attractors, i.e. their collisions with unstable periodic components of the
higher branches of SE states in the nonautonomous microwave phonon laser.


title: Proper J-holomorphic discs in Stein domains of dimension 2

abstract:
  We prove the existence of global Bishop discs in a strictly pseudoconvex
Stein domain in an almost complex manifold of complex dimension 2.


title: Anisotropic thermo-elasticity in 2D -- Part I: A unified approach

abstract:
  In this note we develop tools and techniques for the treatment of anisotropic
thermo-elasticity in two space dimensions. We use a diagonalisation technique
to obtain properties of the characteristic roots of the full symbol of the
system in order to prove $L^p$--$L^q$ decay rates for its solutions.


title: I-V characteristics of the vortex state in MgB2 thin films

abstract:
  The current-voltage (I-V) characteristics of various MgB2 films have been
studied at different magnetic fields parallel to c-axis. At fields \mu0H
between 0 and 5T, vortex liquid-glass transitions were found in the I-V
isotherms. Consistently, the I-V curves measured at different temperatures show
a scaling behavior in the framework of quasi-two-dimension (quasi-2D) vortex
glass theory. However, at \mu0 H >= 5T, a finite dissipation was observed down
to the lowest temperature here, T=1.7K, and the I-V isotherms did not scale in
terms of any known scaling law, of any dimensionality. We suggest that this may
be caused by a mixture of \sigma band vortices and \pi band quasiparticles.
Interestingly, the I-V curves at zero magnetic field can still be scaled
according to the quasi-2D vortex glass formalism, indicating an equivalent
effect of self-field due to persistent current and applied magnetic field.


title: Magnetic Fingerprints of sub-100 nm Fe Nanodots

abstract:
  Sub-100 nm nanomagnets not only are technologically important, but also
exhibit complex magnetization reversal behaviors as their dimensions are
comparable to typical magnetic domain wall widths. Here we capture magnetic
"fingerprints" of 1 billion Fe nanodots as they undergo a single domain to
vortex state transition, using a first-order reversal curve (FORC) method. As
the nanodot size increases from 52 nm to 67 nm, the FORC diagrams reveal
striking differences, despite only subtle changes in their major hysteresis
loops. The 52 nm nanodots exhibit single domain behavior and the coercivity
distribution extracted from the FORC distribution agrees well with a
calculation based on the measured nanodot size distribution. The 58 and 67 nm
nanodots exhibit vortex states, where the nucleation and annihilation of the
vortices are manifested as butterfly-like features in the FORC distribution and
confirmed by micromagnetic simulations. Furthermore, the FORC method gives
quantitative measures of the magnetic phase fractions, and vortex nucleation
and annihilation fields.


title: An online repository of Swift/XRT light curves of GRBs

abstract:
  Context. Swift data are revolutionising our understanding of Gamma Ray
Bursts. Since bursts fade rapidly, it is desirable to create and disseminate
accurate light curves rapidly.
  Aims. To provide the community with an online repository of X-ray light
curves obtained with Swift. The light curves should be of the quality expected
of published data, but automatically created and updated so as to be
self-consistent and rapidly available. Methods. We have produced a suite of
programs which automatically generates Swift/XRT light curves of GRBs. Effects
of the damage to the CCD, automatic readout-mode switching and pile-up are
appropriately handled, and the data are binned with variable bin durations, as
necessary for a fading source.
  Results. The light curve repository website
(http://www.swift.ac.uk/xrt_curves) contains light curves, hardness ratios and
deep images for every GRB which Swift's XRT has observed. When new GRBs are
detected, light curves are created and updated within minutes of the data
arriving at the UK Swift Science Data Centre.


title: On the total disconnectedness of the quotient Aubry set

abstract:
  In this paper we show that the quotient Aubry set associated to certain
Lagrangians is totally disconnected (i.e., every connected component consists
of a single point). Moreover, we discuss the relation between this problem and
a Morse-Sard type property for (difference of) critical subsolutions of
Hamilton-Jacobi equations.


title: New simple modular Lie superalgebras as generalized prolongs

abstract:
  Over algebraically closed fields of characteristic p>2, prolongations of the
simple finite dimensional Lie algebras and Lie superalgebras with Cartan matrix
are studied for certain simplest gradings of these algebras. Several new simple
Lie superalgebras are discovered, serial and exceptional, including superBrown
and superMelikyan superalgebras. Simple Lie superalgebras with Cartan matrix of
rank 2 are classified.


title: Vacuum Structure and Potential

abstract:
  Based on overall experimental observations, especially the pair processes, I
developed a model structure of the vacuum along with a basic-particle formation
scheme begun in 2000 (with collaborator P-I Johansson). The model consists in
that the vacuum is, briefly, filled of neutral but polarizable vacuuons,
consisting each of a p-vaculeon and n- vaculeon of charges $+e$ and $-e$ of
zero rest masses but with spin motions, assumed interacting each other with a
Coulomb force. The model has been introduced in full in a book (Nova Sci, 2005)
and referred to in a number of journal/E-print papers. I outline in this easier
accessible paper the detailed derivation of the model and a corresponding
quantitative determination of the vacuuon size.


title: Counterflow of electrons in two isolated quantum point contacts

abstract:
  We study the interaction between two adjacent but electrically isolated
quantum point contacts (QPCs). At high enough source-drain bias on one QPC, the
drive QPC, we detect a finite electric current in the second, unbiased,
detector QPC. The current generated at the detector QPC always flows in the
opposite direction than the current of the drive QPC. The generated current is
maximal, if the detector QPC is tuned to a transition region between its
quantized conductance plateaus and the drive QPC is almost pinched-off. We
interpret this counterflow phenomenon in terms of an asymmetric phonon-induced
excitation of electrons in the leads of the detector QPC.


title: PAH emission and star formation in the host of the z~2.56 Cloverleaf QSO

abstract:
  We report the first detection of the 6.2micron and 7.7micron infrared `PAH'
emission features in the spectrum of a high redshift QSO, from the Spitzer-IRS
spectrum of the Cloverleaf lensed QSO (H1413+117, z~2.56). The ratio of PAH
features and rest frame far-infrared emission is the same as in lower
luminosity star forming ultraluminous infrared galaxies and in local PG QSOs,
supporting a predominantly starburst nature of the Cloverleaf's huge
far-infrared luminosity (5.4E12 Lsun, corrected for lensing). The Cloverleaf's
period of dominant QSO activity (Lbol ~ 7E13 Lsun) is coincident with an
intense (star formation rate ~1000 Msun/yr) and short (gas exhaustion time
~3E7yr) star forming event.


title: Causal dissipative hydrodynamics for QGP fluid in 2+1 dimensions

abstract:
  In 2nd order causal dissipative theory, space-time evolution of QGP fluid is
studied in 2+1 dimensions. Relaxation equations for shear stress tensors are
solved simultaneously with the energy-momentum conservation equations.
Comparison of evolution of ideal and viscous QGP fluid, initialized under the
same conditions, e.g. same equilibration time, energy density and velocity
profile, indicate that in a viscous dynamics, energy density or temperature of
the fluid evolve slowly, than in an ideal fluid. Cooling gets slower as
viscosity increases. Transverse expansion also increases in a viscous dynamics.
For the first time we have also studied elliptic flow of 'quarks' in causal
viscous dynamics. It is shown that elliptic flow of quarks saturates due to
non-equilibrium correction to equilibrium distribution function, and can not be
mimicked by an ideal hydrodynamics.


title: A Single Trapped Ion as a Time-Dependent Harmonic Oscillator

abstract:
  We show how a single trapped ion may be used to test a variety of important
physical models realized as time-dependent harmonic oscillators. The ion itself
functions as its own motional detector through laser-induced electronic
transitions. Alsing et al. [Phys. Rev. Lett. 94, 220401 (2005)] proposed that
an exponentially decaying trap frequency could be used to simulate (thermal)
Gibbons-Hawking radiation in an expanding universe, but the Hamiltonian used
was incorrect. We apply our general solution to this experimental proposal,
correcting the result for a single ion and showing that while the actual
spectrum is different from the Gibbons-Hawking case, it nevertheless shares an
important experimental signature with this result.


title:
Compounding Fields and Their Quantum Equations in the Trigintaduonion
  Space

abstract:
  The 32-dimensional compounding fields and their quantum interplays in the
trigintaduonion space can be presented by analogy with octonion and sedenion
electromagnetic, gravitational, strong and weak interactions. In the
trigintaduonion fields which are associated with the electromagnetic,
gravitational, strong and weak interactions, the study deduces some conclusions
of field source particles (quarks and leptons) and intermediate particles which
are consistent with current some sorts of interaction theories. In the
trigintaduonion fields which are associated with the hyper-strong and
strong-weak fields, the paper draws some predicts and conclusions of the field
source particles (sub-quarks) and intermediate particles. The research results
show that there may exist some new particles in the nature.


title: Topological defects, geometric phases, and the angular momentum of light

abstract:
  Recent reports on the intriguing features of vector vortex bearing beams are
analyzed using geometric phases in optics. It is argued that the spin
redirection phase induced circular birefringence is the origin of topological
phase singularities arising in the inhomogeneous polarization patterns. A
unified picture of recent results is presented based on this proposition.
Angular momentum shift within the light beam (OAM) has exact equivalence with
the angular momentum holonomy associated with the geometric phase consistent
with our conjecture.


title:
Circular and non-circular nearly horizon-skimming orbits in Kerr
  spacetimes

abstract:
  We have performed a detailed analysis of orbital motion in the vicinity of a
nearly extremal Kerr black hole. For very rapidly rotating black holes (spin
a=J/M>0.9524M) we have found a class of very strong field eccentric orbits
whose angular momentum L_z increases with the orbit's inclination with respect
to the equatorial plane, while keeping latus rectum and eccentricity fixed.
This behavior is in contrast with Newtonian intuition, and is in fact opposite
to the "normal" behavior of black hole orbits. Such behavior was noted
previously for circular orbits; since it only applies to orbits very close to
the black hole, they were named "nearly horizon-skimming orbits". Our analysis
generalizes this result, mapping out the full generic (inclined and eccentric)
family of nearly horizon-skimming orbits. The earlier work on circular orbits
reported that, under gravitational radiation emission, nearly horizon-skimming
orbits tend to evolve to smaller orbit inclination, toward prograde equatorial
configuration. Normal orbits, by contrast, always demonstrate slowly growing
orbit inclination (orbits evolve toward the retrograde equatorial
configuration). Using up-to-date Teukolsky-fluxes, we have concluded that the
earlier result was incorrect: all circular orbits, including nearly
horizon-skimming ones, exhibit growing orbit inclination. Using kludge fluxes
based on a Post-Newtonian expansion corrected with fits to circular and to
equatorial Teukolsky-fluxes, we argue that the inclination grows also for
eccentric nearly horizon-skimming orbits. We also find that the inclination
change is, in any case, very small. As such, we conclude that these orbits are
not likely to have a clear and peculiar imprint on the gravitational waveforms
expected to be measured by the space-based detector LISA.


title: The Blue Straggler Population of the Globular Cluster M5

abstract:
  By combining high-resolution HST and wide-field ground based observations, in
ultraviolet and optical bands, we study the Blue Stragglers Star (BSS)
population of the galactic globular cluster M5 (NGC 5904) from its very central
regions up to its periphery. The BSS distribution is highly peaked in the
cluster center, decreases at intermediate radii and rises again outward. Such a
bimodal distribution is similar to those previously observed in other globular
clusters (M3, 47Tucanae, NGC6752). As for these clusters, dynamical simulations
suggest that, while the majority of BSS in M5 could be originated by stellar
collisions, a significant fraction (20-40%) of BSS generated by mass transfer
processes in primordial binaries is required to reproduce the observed radial
distribution. A candidate BSS has been detected beyond the cluster tidal
radius. If confirmed, this could represent an interesting case of an
"evaporating" BSS.


title: Entanglement entropy of two-dimensional Anti-de Sitter black holes

abstract:
  Using the AdS/CFT correspondence we derive a formula for the entanglement
entropy of the anti-de Sitter black hole in two spacetime dimensions. The
leading term in the large black hole mass expansion of our formula reproduces
exactly the Bekenstein-Hawking entropy S_{BH}, whereas the subleading term
behaves as ln S_{BH}. This subleading term has the universal form typical for
the entanglement entropy of physical systems described by effective conformal
fields theories (e.g. one-dimensional statistical models at the critical
point). The well-known form of the entanglement entropy for a two-dimensional
conformal field theory is obtained as analytic continuation of our result and
is related with the entanglement entropy of a black hole with negative mass.


title: Towards self-consistent definition of instanton liquid parameters

abstract:
  The possibility of self-consistent determination of instanton liquid
parameters is discussed together with the definition of optimal pseudo-particle
configurations and comparing the various pseudo-particle ensembles. The
weakening of repulsive interactions between pseudo-particles is argued and
estimated.


title: Some aspects of the nonperturbative renormalization of the phi^4 model

abstract:
  A nonperturbative renormalization of the phi^4 model is considered. First we
integrate out only a single pair of conjugated modes with wave vectors +/- q.
Then we are looking for the RG equation which would describe the transformation
of the Hamiltonian under the integration over a shell Lambda - d Lambda < k <
Lambda, where d Lambda -> 0. We show that the known Wegner--Houghton equation
is consistent with the assumption of a simple superposition of the integration
results for +/- q. The renormalized action can be expanded in powers of the
phi^4 coupling constant u in the high temperature phase at u -> 0. We compare
the expansion coefficients with those exactly calculated by the diagrammatic
perturbative method, and find some inconsistency. It causes a question in which
sense the Wegner-Houghton equation is really exact.


title: Instanton Liquid at Finite Temperature and Chemical Potential of Quarks

abstract:
  Instanton liquid in heated and strongly interacting matter is studied using
the variational principle. The dependence of the instanton liquid density
(gluon condensate) on the temperature and the quark chemical potential is
determined under the assumption that, at finite temperatures, the dominant
contribution is given by an ensemble of calorons. The respective one-loop
effective quark Lagrangian is used.


title: Eternal inflation and localization on the landscape

abstract:
  We model the essential features of eternal inflation on the landscape of a
dense discretuum of vacua by the potential $V(\phi)=V_{0}+\delta V(\phi)$,
where $|\delta V(\phi)|\ll V_{0}$ is random. We find that the diffusion of the
distribution function $\rho(\phi,t)$ of the inflaton expectation value in
different Hubble patches may be suppressed due to the effect analogous to the
Anderson localization in disordered quantum systems. At $t \to \infty$ only the
localized part of the distribution function $\rho (\phi, t)$ survives which
leads to dynamical selection principle on the landscape. The probability to
measure any but a small value of the cosmological constant in a given Hubble
patch on the landscape is exponentially suppressed at $t\to \infty$.


title:
Singularity Resolution in Isotropic Loop Quantum Cosmology: Recent
  Developments

abstract:
  Since the past Iagrg meeting in December 2004, new developments in loop
quantum cosmology have taken place, especially with regards to the resolution
of the Big Bang singularity in the isotropic models. The singularity resolution
issue has been discussed in terms of physical quantities (expectation values of
Dirac observables) and there is also an ``improved'' quantization of the
Hamiltonian constraint. These developments are briefly discussed.
  This is an expanded version of the review talk given at the
24$^{\mathrm{th}}$ IAGRG meeting in February 2007.


title: Vortices in Bose-Einstein Condensates: Theory

abstract:
  Vortices are pervasive in nature, representing the breakdown of laminar fluid
flow and hence playing a key role in turbulence. The fluid rotation associated
with a vortex can be parameterized by the circulation $\Gamma=\oint {\rm d}{\bf
r}\cdot{\bf v}({\bf r})$ about the vortex, where ${\bf v}({\bf r})$ is the
fluid velocity field. While classical vortices can take any value of
circulation, superfluids are irrotational, and any rotation or angular momentum
is constrained to occur through vortices with quantized circulation. Quantized
vortices also play a key role in the dissipation of transport in superfluids.
In BECs quantized vortices have been observed in several forms, including
single vortices, vortex lattices, and vortex pairs and rings. The recent
observation of quantized vortices in a fermionic gas was taken as a clear
signature of the underlying condensation and superfluidity of fermion pairs. In
addition to BECs, quantized vortices also occur in superfluid Helium, nonlinear
optics, and type-II superconductors.


title: A POVM view of the ensemble approach to polarization optics

abstract:
  Statistical ensemble formalism of Kim, Mandel and Wolf (J. Opt. Soc. Am. A 4,
433 (1987)) offers a realistic model for characterizing the effect of
stochastic non-image forming optical media on the state of polarization of
transmittedlight. With suitable choice of the Jones ensemble, various Mueller
transformations - some of which have been unknown so far - are deduced. It is
observed that the ensemble approach is formally identical to the positive
operator valued measures (POVM) on the quantum density matrix. This
observation, in combination with the recent suggestion by Ahnert and Payne
(Phys. Rev. A 71, 012330, (2005)) - in the context of generalized quantum
measurement on single photon polarization states - that linear optics elements
can be employed in setting up all possible POVMs, enables us to propose a way
of realizing different types of Mueller devices.


title:
Reexamination of spin decoherence in semiconductor quantum dots from
  equation-of-motion approach

abstract:
  The longitudinal and transversal spin decoherence times, $T_1$ and $T_2$, in
semiconductor quantum dots are investigated from equation-of-motion approach
for different magnetic fields, quantum dot sizes, and temperatures. Various
mechanisms, such as the hyperfine interaction with the surrounding nuclei, the
Dresselhaus spin-orbit coupling together with the electron--bulk-phonon
interaction, the $g$-factor fluctuations, the direct spin-phonon coupling due
to the phonon-induced strain, and the coaction of the
electron--bulk/surface-phonon interaction together with the hyperfine
interaction are included. The relative contributions from these spin
decoherence mechanisms are compared in detail. In our calculation, the
spin-orbit coupling is included in each mechanism and is shown to have marked
effect in most cases. The equation-of-motion approach is applied in studying
both the spin relaxation time $T_1$ and the spin dephasing time $T_2$, either
in Markovian or in non-Markovian limit. When many levels are involved at finite
temperature, we demonstrate how to obtain the spin relaxation time from the
Fermi Golden rule in the limit of weak spin-orbit coupling. However, at high
temperature and/or for large spin-orbit coupling, one has to use the
equation-of-motion approach when many levels are involved. Moreover, spin
dephasing can be much more efficient than spin relaxation at high temperature,
though the two only differs by a factor of two at low temperature.


title: Construction of initial data for 3+1 numerical relativity

abstract:
  This lecture is devoted to the problem of computing initial data for the
Cauchy problem of 3+1 general relativity. The main task is to solve the
constraint equations. The conformal technique, introduced by Lichnerowicz and
enhanced by York, is presented. Two standard methods, the conformal
transverse-traceless one and the conformal thin sandwich, are discussed and
illustrated by some simple examples. Finally a short review regarding initial
data for binary systems (black holes and neutron stars) is given.


title:
Magnetism and Thermodynamics of Spin-1/2 Heisenberg Diamond Chains in a
  Magnetic Field

abstract:
  The magnetic and thermodynamic properties of spin-1/2 Heisenberg diamond
chains are investigated in three different cases: (a) J1, J2, J3>0
(frustrated); (b) J1, J3<0, J2>0 (frustrated); and (c) J1, J2>0, J3<0
(non-frustrated). The density matrix renormalization group (DMRG) technique is
invoked to study the properties of the system in the ground state, while the
transfer matrix renormalization group (TMRG) technique is applied to explore
the thermodynamic properties. The local magnetic moments, spin correlation
functions, and static structure factors are discussed in the ground state for
the three cases. It is shown that the static structure factor S(q) shows peaks
at wavevectors $q=a\pi /3$ (a=0,1,2,3,4,5) for different couplings in a zero
magnetic field, which, however in the magnetic fields where the magnetization
plateau with m=1/6 pertains, exhibits the peaks only at q=0, $2\pi /3$ and
$4\pi /3$, which are found to be couplings-independent. The DMRG results of the
zero-field static structure factor can be nicely fitted by a linear
superposition of six modes, where two fitting equations are proposed. It is
observed that the six modes are closely related to the low-lying excitations of
the system. At finite temperatures, the double-peak structures of the
susceptibility and specific heat against temperature are obtained, where the
peak positions and heights are found to depend on the competition of the
couplings. It is also uncovered that the XXZ anisotropy of F and AF couplings
leads the system of case (c) to display quite different behaviors. In addition,
the experimental data of the susceptibility, specific heat and magnetization
for the compound Cu$_{3}$(CO$_{3}$)$_{2}$(OH)$_{2}$ are fairly compared with
our TMRG results.


title: Extraction of physical laws from joint experimental data

abstract:
  The extraction of a physical law y=yo(x) from joint experimental data about x
and y is treated. The joint, the marginal and the conditional probability
density functions (PDF) are expressed by given data over an estimator whose
kernel is the instrument scattering function. As an optimal estimator of yo(x)
the conditional average is proposed. The analysis of its properties is based
upon a new definition of prediction quality. The joint experimental information
and the redundancy of joint measurements are expressed by the relative entropy.
With the number of experiments the redundancy on average increases, while the
experimental information converges to a certain limit value. The difference
between this limit value and the experimental information at a finite number of
data represents the discrepancy between the experimentally determined and the
true properties of the phenomenon. The sum of the discrepancy measure and the
redundancy is utilized as a cost function. By its minimum a reasonable number
of data for the extraction of the law yo(x) is specified. The mutual
information is defined by the marginal and the conditional PDFs of the
variables. The ratio between mutual information and marginal information is
used to indicate which variable is the independent one. The properties of the
introduced statistics are demonstrated on deterministically and randomly
related variables.


title: Kinetic equation for finite systems of fermions with pairing

abstract:
  The solutions of the Wigner-transformed time-dependent
Hartree--Fock--Bogoliubov equations are studied in the constant-$\Delta$
approximation. This approximation is known to violate particle-number
conservation. As a consequence, the density fluctuation and the longitudinal
response function given by this approximation contain spurious contributions. A
simple prescription for restoring both local and global particle-number
conservation is proposed. Explicit expressions for the eigenfrequencies of the
correlated systems and for the density response function are derived and it is
shown that the semiclassical analogous of the quantum single--particle spectrum
has an excitation gap of $2\Delta$, in agreement with the quantum result. The
collective response is studied for a simplified form of the residual
interaction.


title:
Reciprocal Symmetry and Classical Discrete Oscillator Incorporating
  Half-Integral Energy Levels

abstract:
  Classical oscillator differential equation is replaced by the corresponding
(finite time) difference equation. The equation is, then, symmetrized so that
it remains invariant under the change d going to -d, where d is the smallest
span of time. This symmetric equation has solutions, which come in reciprocally
related pairs. One member of a pair agrees with the classical solution and the
other is an oscillating solution and does not converge to a limit as d goes to
0. This solution contributes to oscillator energy a term which is a multiple of
half-integers.


title: Hadrons in Medium -- Theory confronts experiment

abstract:
  In this talk we briefly summarize our theoretical understanding of in-medium
selfenergies of hadrons. With the special case of the $\omega$ meson we
demonstrate that earlier calculations that predicted a significant lowering of
the mass in medium are based on an incorrect treatment of the model Lagrangian;
more consistent calculations lead to a significant broadening, but hardly any
mass shift. We stress that the experimental reconstruction of hadron spectral
functions from measured decay products always requires knowledge of the decay
branching ratios which may also be strongly mass-dependent. It also requires a
quantitatively reliable treatment of final state interactions which has to be
part of any reliable theory.


title:
A computer program for fast non-LTE analysis of interstellar line
  spectra

abstract:
  The large quantity and high quality of modern radio and infrared line
observations require efficient modeling techniques to infer physical and
chemical parameters such as temperature, density, and molecular abundances. We
present a computer program to calculate the intensities of atomic and molecular
lines produced in a uniform medium, based on statistical equilibrium
calculations involving collisional and radiative processes and including
radiation from background sources. Optical depth effects are treated with an
escape probability method. The program is available on the World Wide Web at
http://www.sron.rug.nl/~vdtak/radex/index.shtml . The program makes use of
molecular data files maintained in the Leiden Atomic and Molecular Database
(LAMDA), which will continue to be improved and expanded. The performance of
the program is compared with more approximate and with more sophisticated
methods. An Appendix provides diagnostic plots to estimate physical parameters
from line intensity ratios of commonly observed molecules. This program should
form an important tool in analyzing observations from current and future radio
and infrared telescopes.


title:
Nonlinear force-free coronal magnetic field extrapolation scheme based
  on the direct boundary integral formulation

abstract: This paper has been withdrawn by the authors.


title:
Alternative Approaches to the Equilibrium Properties of Hard-Sphere
  Liquids

abstract:
  An overview of some analytical approaches to the computation of the
structural and thermodynamic properties of single component and multicomponent
hard-sphere fluids is provided. For the structural properties, they yield a
thermodynamically consistent formulation, thus improving and extending the
known analytical results of the Percus-Yevick theory. Approximate expressions
for the contact values of the radial distribution functions and the
corresponding analytical equations of state are also discussed. Extensions of
this methodology to related systems, such as sticky hard spheres and
square-well fluids, as well as its use in connection with the perturbation
theory of fluids are briefly addressed.


title: Complexities of Human Promoter Sequences

abstract:
  By means of the diffusion entropy approach, we detect the scale-invariance
characteristics embedded in the 4737 human promoter sequences. The exponent for
the scale-invariance is in a wide range of $[ {0.3,0.9} ]$, which centered at
$\delta_c = 0.66$. The distribution of the exponent can be separated into left
and right branches with respect to the maximum. The left and right branches are
asymmetric and can be fitted exactly with Gaussian form with different widths,
respectively.


title: Evidence for an excitonic insulator phase in 1T-TiSe$_{2}$

abstract:
  We present a new high-resolution angle-resolved photoemission study of
1\textit{T}-TiSe$_{2}$ in both, its room-temperature, normal phase and its
low-temperature, charge-density wave phase. At low temperature the
photoemission spectra are strongly modified, with large band renormalisations
at high-symmetry points of the Brillouin zone and a very large transfer of
spectral weight to backfolded bands. A theoretical calculation of the spectral
function for an excitonic insulator phase reproduces the experimental features
with very good agreement. This gives strong evidence in favour of the excitonic
insulator scenario as a driving force for the charge-density wave transition in
1\textit{T}-TiSe$_{2}$.


title: Oxygen-rich droplets and the enrichment of the ISM

abstract:
  We argue that the discrepancies observed in HII regions between abundances
derived from optical recombination lines (ORLs) and collisionally excited lines
(CELs) might well be the signature of a scenario of the enrichment of the
interstellar medium (ISM) proposed by Tenorio-Tagle (1996). In this scenario,
the fresh oxygen released during massive supernova explosions is confined
within the hot superbubbles as long as supernovae continue to explode. Only
after the last massive supernova explosion, the metal-rich gas starts cooling
down and falls on the galaxy within metal-rich droplets. Full mixing of these
metal-rich droplets and the ISM occurs during photoionization by the next
generations of massive stars. During this process, the metal-rich droplets give
rise to strong recombination lines of the metals, leading to the observed
ORL-CEL discrepancy. (The full version of this work is submitted to Astronomy
and Astrophysics.)


title:
Soft modes and NTE in Zn(CN)2 from Raman spectroscopy and first
  principles calculations

abstract:
  We have studied Zn(CN)2 at high pressure using Raman spectroscopy, and report
Gruneisen parameters of the soft phonons. The phonon frequencies and eigen
vectors obtained from ab-initio calculations are used for the assignment of the
observed phonon spectra. Out of the eleven zone-centre optical modes, six modes
exhibit negative Gruneisen parameter. The calculations suggest that the soft
phonons correspond to the librational and translational modes of CN rigid unit,
with librational modes contributing more to thermal expansion. A rapid
disordering of the lattice is found above 1.6 GPa from X-ray diffraction.


title: Estimation of experimental data redundancy and related statistics

abstract:
  Redundancy of experimental data is the basic statistic from which the
complexity of a natural phenomenon and the proper number of experiments needed
for its exploration can be estimated. The redundancy is expressed by the
entropy of information pertaining to the probability density function of
experimental variables. Since the calculation of entropy is inconvenient due to
integration over a range of variables, an approximate expression for redundancy
is derived that includes only a sum over the set of experimental data about
these variables. The approximation makes feasible an efficient estimation of
the redundancy of data along with the related experimental information and
information cost function. From the experimental information the complexity of
the phenomenon can be simply estimated, while the proper number of experiments
needed for its exploration can be determined from the minimum of the cost
function. The performance of the approximate estimation of these statistics is
demonstrated on two-dimensional normally distributed random data.


title: Effective potentials for quasicrystals from ab-initio data

abstract:
  Classical effective potentials are indispensable for any large-scale
atomistic simulations, and the relevance of simulation results crucially
depends on the quality of the potentials used. For complex alloys like
quasicrystals, however, realistic effective potentials are practically
inexistent. We report here on our efforts to develop effective potentials
especially for quasicrystalline alloy systems. We use the so-called force
matching method, in which the potential parameters are adapted so as to
optimally reproduce the forces and energies in a set of suitably chosen
reference configurations. These reference data are calculated with ab-initio
methods. As a first application, EAM potentials for decagonal Al-Ni-Co,
icosahedral Ca-Cd, and both icosahedral and decagonal Mg-Zn quasicrystals have
been constructed. The influence of the potential range and degree of
specialisation on the accuracy and other properties is discussed and compared.


title: On smooth foliations with Morse singularities

abstract:
  Let $M$ be a smooth manifold and let $\F$ be a codimension one, $C^\infty$
foliation on $M$, with isolated singularities of Morse type. The study and
classification of pairs $(M,\F)$ is a challenging (and difficult) problem. In
this setting, a classical result due to Reeb \cite{Reeb} states that a manifold
admitting a foliation with exactly two center-type singularities is a sphere.
In particular this is true if the foliation is given by a function. Along these
lines a result due to Eells and Kuiper \cite{Ku-Ee} classify manifolds having a
real-valued function admitting exactly three non-degenerate singular points. In
the present paper, we prove a generalization of the above mentioned results. To
do this, we first describe the possible arrangements of pairs of singularities
and the corresponding codimension one invariant sets, and then we give an
elimination procedure for suitable center-saddle and some saddle-saddle
configurations (of consecutive indices). In the second part, we investigate if
other classical results, such as Haefliger and Novikov (Compact Leaf) theorems,
proved for regular foliations, still hold true in presence of singularities. At
this purpose, in the singular set, $Sing(\F)$ of the foliation $\F$, we
consider {\em{weakly stable}} components, that we define as those components
admitting a neighborhood where all leaves are compact. If $Sing(\F)$ admits
only weakly stable components, given by smoothly embedded curves diffeomorphic
to $S^1$, we are able to extend Haefliger's theorem. Finally, the existence of
a closed curve, transverse to the foliation, leads us to state a Novikov-type
result.


title: Frobenius-Schur indicators for semisimple Lie algebras

abstract:
  Let g be a finite dimensional complex semisimple Lie algebra, and let V be a
finite dimensional represenation of g. We give a closed formula for the mth
Frobenius-Schur indicator, m>1, of V in representation-theoretic terms. We
deduce that the indicators take integer values, and that for a large enough m,
the mth indicator of V equals the dimension of the zero weight space of V. For
the classical Lie algebras sl(n), so(2n), so(2n+1) and sp(2n), this is the case
for m greater or equal to 2n-1, 4n-5, 4n-3 and 2n+1, respectively.


title: Supersymmetry breaking metastable vacua in runaway quiver gauge theories

abstract:
  In this paper we consider quiver gauge theories with fractional branes whose
infrared dynamics removes the classical supersymmetric vacua (DSB branes). We
show that addition of flavors to these theories (via additional non-compact
branes) leads to local meta-stable supersymmetry breaking minima, closely
related to those of SQCD with massive flavors. We simplify the study of the
one-loop lifting of the accidental classical flat directions by direct
computation of the pseudomoduli masses via Feynman diagrams. This new approach
allows to obtain analytic results for all these theories. This work extends the
results for the $dP_1$ theory in hep-th/0607218. The new approach allows to
generalize the computation to general examples of DSB branes, and for arbitrary
values of the superpotential couplings.


title: Low Energy Aspects of Heavy Meson Decays

abstract:
  I discuss low energy aspects of heavy meson decays, where there is at least
one heavy meson in the final state. Examples are $B -\bar{B}$ mixing, $B \to D
\bar{D}$, $B \to D \eta'$, and $B \to D \gamma$. %and $B \to D W $ (Isgur-Wise
function). The analysis is performed in the heavy quark limit within
heavy-light chiral perturbation theory. Coefficients of $1/N_c$ suppressed
chiral Lagrangian terms (beyond factorization) have been estimated by means of
a heavy-light chiral quark model.


title:
Radiative losses and cut-offs of energetic particles at relativistic
  shocks

abstract:
  We investigate the acceleration and simultaneous radiative losses of
electrons in the vicinity of relativistic shocks. Particles undergo pitch angle
diffusion, gaining energy as they cross the shock by the Fermi mechanism and
also emitting synchrotron radiation in the ambient magnetic field. A
semi-analytic approach is developed which allows us to consider the behaviour
of the shape of the spectral cut-off and the variation of that cut-off with the
particle pitch angle. The implications for the synchrotron emission of
relativistic jets, such as those in gamma ray burst sources and blazars, are
discussed.


title: Very strong and slowly varying magnetic fields as source of axions

abstract:
  The investigation on the production of particles in slowly varying but
extremely intense magnetic field in extended to the case of axions. The
motivation is, as for some previously considered cases, the possibility that
such kind of magnetic field may exist around very compact astrophysical
objects.


title: Symmetry disquisition on the TiOX phase diagram

abstract:
  The sequence of phase transitions and the symmetry of in particular the low
temperature incommensurate and spin-Peierls phases of the quasi one-dimensional
inorganic spin-Peierls system TiOX (TiOBr and TiOCl) have been studied using
inelastic light scattering experiments. The anomalous first-order character of
the transition to the spin-Peierls phase is found to be a consequence of the
different symmetries of the incommensurate and spin-Peierls (P$2_{1}/m$)
phases.
  The pressure dependence of the lowest transition temperature strongly
suggests that magnetic interchain interactions play an important role in the
formation of the spin-Peierls and the incommensurate phases. Finally, a
comparison of Raman data on VOCl to the TiOX spectra shows that the high energy
scattering observed previously has a phononic origin.


title: Discovery of a point-like very-high-energy gamma-ray source in Monoceros

abstract:
  The complex Monoceros Loop SNR/Rosette Nebula region contains several
potential sources of very-high-energy (VHE) gamma-ray emission and two as yet
unidentified high-energy EGRET sources. Sensitive VHE observations are required
to probe acceleration processes in this region. The H.E.S.S. telescope array
has been used to search for very high-energy gamma-ray sources in this region.
CO data from the NANTEN telescope were used to map the molecular clouds in the
region, which could act as target material for gamma-ray production via
hadronic interactions. We announce the discovery of a new gamma-ray source,
HESS J0632+058, located close to the rim of the Monoceros SNR. This source is
unresolved by H.E.S.S. and has no clear counterpart at other wavelengths but is
possibly associated with the weak X-ray source 1RXS J063258.3+054857, the
Be-star MWC 148 and/or the lower energy gamma-ray source 3EG J0634+0521. No
evidence for an associated molecular cloud was found in the CO data.


title: Thermal entanglement of qubit pairs on the Shastry-Sutherland lattice

abstract:
  We show that temperature and magnetic field properties of the entanglement
between spins on the two-dimensional Shastry-Sutherland lattice can be
qualitatively described by analytical results for a qubit tetramer. Exact
diagonalization of clusters with up to 20 sites reveals that the regime of
fully entangled neighboring pairs coincides with the regime of finite spin gap
in the spectrum. Additionally, the results for the regime of vanishing spin gap
are discussed and related to the Heisenberg limit of the model.


title: Bonding of H in O vacancies of ZnO

abstract:
  We investigate the bonding of H in O vacancies of ZnO using density
functional calculations. We find that H is anionic and does not form
multicenter bonds with Zn in this compound.


title:
Reparametrization Invariance, the controversial extraction of $\alpha$
  from $B\to\pi\pi$ and New Physics

abstract:
  The extraction of the weak phase $\alpha$ from $B\to\pi\pi$ decays has been
controversial from a statistical point of view, as the frequentist vs. bayesian
confrontation shows. We analyse several relevant questions which have not
deserved full attention and pervade the extraction of $\alpha$.
Reparametrization Invariance proves appropriate to understand those issues. We
show that some Standard Model inspired parametrizations can be senseless or
inadequate if they go beyond the minimal Gronau and London assumptions: the
single weak phase $\alpha$ just in the $\Delta I=3/2$ amplitudes, the isospin
relations and experimental data. Beside those analyses, we extract $\alpha$
through the use of several adequate parametrizations, showing that there is no
relevant discrepancy between frequentist and bayesian results. The most
relevant information, in terms of $\alpha$, is the exclusion of values around
$\alpha\sim \pi/4$; this result is valid in the presence of arbitrary New
Physics contributions to the $\Delta I=1/2$ piece.


title: Solar System Constraints on Gauss-Bonnet Mediated Dark Energy

abstract:
  Although the Gauss-Bonnet term is a topological invariant for general
relativity, it couples naturally to a quintessence scalar field, modifying
gravity at solar system scales. We determine the solar system constraints due
to this term by evaluating the post-Newtonian metric for a distributional
source. We find a mass dependent, 1/r^7 correction to the Newtonian potential,
and also deviations from the Einstein gravity prediction for light-bending. We
constrain the parameters of the theory using planetary orbits, the Cassini
spacecraft data, and a laboratory test of Newton's law, always finding
extremely tight bounds on the energy associated to the Gauss-Bonnet term. We
discuss the relevance of these constraints to late-time cosmological
acceleration.


title:
Switching mechanism of photochromic diarylethene derivatives molecular
  junctions

abstract:
  The electronic transport properties and switching mechanism of single
photochromic diarylethene derivatives sandwiched between two gold surfaces with
closed and open configurations are investigated by a fully self-consistent
nonequilibrium Green's function method combined with density functional theory.
The calculated transmission spectra of two configurations are strikingly
distinctive. The open form lacks any significant transmission peak within a
wide energy window, while the closed structure has two significant transmission
peaks on the both sides of the Fermi level. The electronic transport properties
of the molecular junction with closed structure under a small bias voltage are
mainly determined by the tail of the transmission peak contributed unusually by
the perturbed lowest perturbed unoccupied molecular orbital. The calculated
on-off ratio of currents between the closed and open configurations is about
two orders of magnitude, which reproduces the essential features of the
experimental measured results. Moreover, we find that the switching behavior
within a wide bias voltage window is extremely robust to both substituting F or
S for H or O and varying end anchoring atoms from S to Se and Te.


title:
Robust manipulation of electron spin coherence in an ensemble of singly
  charged quantum dots

abstract:
  Using the recently reported mode locking effect we demonstrate a highly
robust control of electron spin coherence in an ensemble of (In,Ga)As quantum
dots during the single spin coherence time. The spin precession in a transverse
magnetic field can be fully controlled up to 25 K by the parameters of the
exciting pulsed laser protocol such as the pulse train sequence, leading to
adjustable quantum beat bursts in Faraday rotation. Flipping of the electron
spin precession phase was demonstrated by inverting the polarization within a
pulse doublet sequence.


title: Equation of state for dense hydrogen and plasma phase transition

abstract:
  We calculate the equation of state of dense hydrogen within the chemical
picture. Fluid variational theory is generalized for a multi-component system
of molecules, atoms, electrons, and protons. Chemical equilibrium is supposed
for the reactions dissociation and ionization. We identify the region of
thermodynamic instability which is related to the plasma phase transition. The
reflectivity is calculated along the Hugoniot curve and compared with
experimental results. The equation-of-state data is used to calculate the
pressure and temperature profiles for the interior of Jupiter.


title: Experimental nonclassicality of single-photon-added thermal light states

abstract:
  We report the experimental realization and tomographic analysis of novel
quantum light states obtained by exciting a classical thermal field by a single
photon. Such states, although completely incoherent, possess a tunable degree
of quantumness which is here exploited to put to a stringent experimental test
some of the criteria proposed for the proof and the measurement of state
non-classicality. The quantum character of the states is also given in quantum
information terms by evaluating the amount of entanglement that they can
produce.


title: Neutron Skin and Giant Resonances in Nuclei

abstract:
  Some aspects, both experimental and theoretical, of extracting the neutron
skin $\Delta R$ from properties of isovector giant resonances are discussed.
Existing proposals are critically reviewed. The method relying on the energy
difference between the GTR and IAS is shown to lack sensitivity to $\Delta R$.
A simple explanation of the linear relation between the symmetry energy and the
neutron skin is also given.


title: Genetic Optimization of Photonic Bandgap Structures

abstract:
  We investigate the use of a Genetic Algorithm (GA) to design a set of
photonic crystals (PCs) in one and two dimensions. Our flexible design
methodology allows us to optimize PC structures which are optimized for
specific objectives. In this paper, we report the results of several such
GA-based PC optimizations. We show that the GA performs well even in very
complex design spaces, and therefore has great potential for use as a robust
design tool in present and future applications.


title:
Huge magneto-crystalline anisotropy of x-ray linear dichroism observed
  on Co/FeMn bilayers

abstract:
  We present an x-ray spectromicroscopic investigation of single-crystalline
magnetic FeMn/Co bilayers on Cu(001), using X-ray magnetic circular (XMCD) and
linear (XMLD) dichroism at the Co and Fe L3 absorption edges in combination
with photoelectron emission microscopy (PEEM). Using the magnetic coupling
between the ferromagnetic Co layer and the antiferromagnetic FeMn layer we are
able to produce magnetic domains with two different crystallographic
orientations of the magnetic easy axis within the same sample at the same time.
We find a huge difference in the XMLD contrast between the two types of
magnetic domains, which we discuss in terms of intrinsic magneto-crystalline
anisotropy of XMLD of the Co layer. We also demonstrate that due to the high
sensitivity of the method, the small number of induced ferromagnetic Fe moments
at the FeMn-Co interface is sufficient to obtain magnetic contrast from XMLD in
a metallic system.


title:
Temperature Dependence of the Tensile Properties of Single Walled Carbon
  Nanotubes: O(N) Tight Binding MD Simulation

abstract:
  This paper examines the effect of temperature on the structural stability and
mechanical properties of 20 layered (10,10) single walled carbon nanotubes
(SWCNTs) under tensile loading using an O(N) tight binding molecular dynamics
(TBMD) simulation method. We observed that (10,10) tube can sustain its
structural stability for the strain values of 0.23 in elongation and 0.06 in
compression at 300K. Bond breaking strain value decreases with increasing
temperature under streching but not under compression. The elastic limit,
Young's modulus, tensile strength and Poisson ratio are calculated as 0.10,
0.395 TPa, 83.23 GPa, 0.285, respectively, at 300K. In the temperature range
from 300K to 900K; Young's modulus and the tensile strengths are decreasing
with increasing temperature while the Poisson ratio is increasing. At higher
temperatures, Young's modulus starts to increase while the Poisson ratio and
tensile strength decrease. In the temperature range from 1200K to 1800K, the
SWCNT is already deformed and softened. Applying strain on these deformed and
softened SWCNTs do not follow the same pattern as in the temperature range of
300K to 900K.


title: Gamma-ray emitting AGN and GLAST

abstract:
  I describe the different classes of Active Galactic Nuclei (AGN) and the
basic tenets of unified schemes. I then review the properties of the
extragalactic sources detected in the GeV and TeV bands, showing that the vast
majority of them belong to the very rare blazar class. I further discuss the
kind of AGN GLAST is likely to detect, making some predictions going from the
obvious to the likely, all the way to the less probable.


title: Potfit: effective potentials from ab-initio data

abstract:
  We present a program called potfit which generates an effective atomic
interaction potential by matching it to a set of reference data computed in
first-principles calculations. It thus allows to perform large-scale atomistic
simulations of materials with physically justified potentials. We describe the
fundamental principles behind the program, emphasizing its flexibility in
adapting to different systems and potential models, while also discussing its
limitations. The program has been used successfully in creating effective
potentials for a number of complex intermetallic alloys, notably quasicrystals.


title:
Dark energy and neutrino model in SUSY -- Remarks on active and sterile
  neutrinos mixing --

abstract:
  We consider a Mass Varying Neutrinos (MaVaNs) model in supersymmetric theory.
The model includes effects of supersymmetry breaking transmitted by the
gravitational interaction from the hidden sector, in which supersymmetry was
broken, to the dark energy sector. Then evolutions of the neutrino mass and the
equation of state parameter of the dark energy are presented in the model. It
is remarked that only the mass of a sterile neutrino is variable in the case of
the vanishing mixing between the left-handed and a sterile neutrino on
cosmological time scale. The finite mixing makes the mass of the left-handed
neutrino variable.


title:
The transverse proximity effect in spectral hardness on the line of
  sight towards HE 2347-4342

abstract:
  We report the discovery of 14 quasars in the vicinity of HE2347-4342, one of
the two quasars whose intergalactic HeII forest has been resolved with FUSE. By
analysing the HI and the HeII opacity variations separately, no transverse
proximity effect is detected near three foreground quasars of HE2347-4342:
QSOJ23503-4328 (z=2.282, $\vartheta=3.59$ arcmin), QSOJ23500-4319 (z=2.302,
$\vartheta=8.77$ arcmin) and QSOJ23495-4338 (z=2.690, $\vartheta=16.28$
arcmin). This is primarily due to line contamination and overdensities probably
created by large-scale structure. By comparing the HI absorption and the
corresponding HeII absorption, we estimated the fluctuating spectral shape of
the extragalactic UV radiation field along this line of sight. We find that the
UV spectral shape near HE2347-4342 and in the projected vicinity of the three
foreground quasars is statistically harder than expected from UV background
models dominated by quasars. In addition, we find three highly ionised metal
line systems near the quasars. However, they do not yield further constraints
on the shape of the ionising field. We conclude that the foreground quasars
show a transverse proximity effect that is detectable as a local hardening of
the UV radiation field, although the evidence is strongest for QSOJ23495-4338.
Thus, the relative spectral hardness traces the proximity effect also in
overdense regions prohibiting the traditional detection in the HI forest.
Furthermore, we emphasise that softening of quasar radiation by radiative
transfer in the intergalactic medium is important to understand the observed
spectral shape variations. From the transverse proximity effect of
QSOJ23495-4338 we obtain a lower limit on the quasar lifetime of ~25 Myr.


title: Biased random walks on combs

abstract:
  We develop rigorous, analytic techniques to study the behaviour of biased
random walks on combs. This enables us to calculate exactly the spectral
dimension of random comb ensembles for any bias scenario in the teeth or spine.
Two specific examples of random comb ensembles are discussed; the random comb
with nonzero probability of an infinitely long tooth at each vertex on the
spine and the random comb with a power law distribution of tooth lengths. We
also analyze transport properties along the spine for these probability
measures.


title: Monoid generalizations of the Richard Thompson groups

abstract:
  The groups G_{k,1} of Richard Thompson and Graham Higman can be generalized
in a natural way to monoids, that we call M_{k,1}, and to inverse monoids,
called Inv_{k,1}; this is done by simply generalizing bijections to partial
functions or partial injective functions. The monoids M_{k,1} have connections
with circuit complexity (studied in another paper). Here we prove that M_{k,1}
and Inv_{k,1} are congruence-simple for all k. Their Green relations J and D
are characterized: M_{k,1} and Inv_{k,1} are J-0-simple, and they have k-1
non-zero D-classes. They are submonoids of the multiplicative part of the Cuntz
algebra O_k. They are finitely generated, and their word problem over any
finite generating set is in P. Their word problem is coNP-complete over certain
infinite generating sets.
  Changes in this version: Section 4 has been thoroughly revised, and errors
have been corrected; however, the main results of Section 4 do not change.
Sections 1, 2, and 3 are unchanged, except for the proof of Theorem 2.3, which
was incomplete; a complete proof was published in the Appendix of reference
[6], and is also given here.


title:
The Reliability on the Direction of the Incident Neutrino for the Fully
  Contained Events and Partially Contained Events due to QEL in the
  Super-Kamiokande

abstract:
  In the SK analysis of the neutrino events for [Fully Contained Events] and
[Partially Contained Events] on their zenith angle distribution, it is assumed
that the zenith angle of the incident neutrino is the same as that of the
detected charged lepton. In the present paper, we examine the validity of [the
SK assumption on the direction] of the incident neutrinos. Concretely speaking,
we analyze muon-like events due to QEL. For the purpose, we develop [Time
Sequential Monte Carlo Simulation] to extract the conclusion on the validity of
the SK assumption. In our [Time Sequential Simulation], we simulate every
physical process concerned as exactly as possible without any approximation.
  From the comparison between the zenith angle distributon of the emitted muons
under [the SK assumption on the direction] and the corresponding one obtained
under our [Time Sequential Simulation], it is concluded that the measurement of
the direction of the incident neutrino for the neutrino events occurring inside
the detector in the SK analysis turns out to be unreliable, which holds
irrespective of the existence and/or non-existence of the neutrino oscillation.


title: Intricate Knots in Proteins: Function and Evolution

abstract:
  A number of recently discovered protein structures incorporate a rather
unexpected structural feature: a knot in the polypeptide backbone. These knots
are extremely rare, but their occurrence is likely connected to protein
function in as yet unexplored fashion. Our analysis of the complete Protein
Data Bank reveals several new knots which, along with previously discovered
ones, can shed light on such connections. In particular, we identify the most
complex knot discovered to date in human ubiquitin hydrolase, and suggest that
its entangled topology protects it against unfolding and degradation by the
proteasome. Knots in proteins are typically preserved across species and
sometimes even across kingdoms. However, we also identify a knot which only
appears in some transcarbamylases while being absent in homologous proteins of
similar structure. The emergence of the knot is accompanied by a shift in the
enzymatic function of the protein. We suggest that the simple insertion of a
short DNA fragment into the gene may suffice to turn an unknotted into a
knotted structure in this protein.


title: Star Formation in Galaxies with Large Lower Surface Brightness Disks

abstract:
  We present B, R, and Halpha imaging data of 19 large disk galaxies whose
properties are intermediate between classical low surface brightness galaxies
and ordinary high surface brightness galaxies. We use data taken from the
Lowell 1.8m Perkins telescope to determine the galaxies' overall morphology,
color, and star formation properties. Morphologically, the galaxies range from
Sb through Irr and include galaxies with and without nuclear bars. The colors
of the galaxies vary from B-R = 0.3 - 1.9, and most show at least a slight
bluing of the colors with increasing radius. The Halpha images of these
galaxies show an average star formation rate lower than is found for similar
samples with higher surface brightness disks. Additionally, the galaxies
studied have both higher gas mass-to-luminosity and diffuse Halpha emission
than is found in higher surface brightness samples.


title: Domain Wall Dynamics near a Quantum Critical Point

abstract:
  We study the real-time domain-wall dynamics near a quantum critical point of
the one-dimensional anisotropic ferromagnetic spin 1/2 chain. By numerical
simulation, we find the domain wall is dynamically stable in the
Heisenberg-Ising model. Near the quantum critical point, the width of the
domain wall diverges as $(\Delta -1) ^{-1/2}$.


title:
Quantum mechanical approach to decoherence and relaxation generated by
  fluctuating environment

abstract:
  We consider an electrostatic qubit, interacting with a fluctuating charge of
single electron transistor (SET) in the framework of exactly solvable model.
The SET plays a role of the fluctuating environment affecting the qubit's
parameters in a controllable way. We derive the rate equations describing
dynamics of the entire system for both weak and strong qubit-SET coupling.
Solving these equation we obtain decoherence and relaxation rates of the qubit,
as well as the spectral density of the fluctuating qubit's parameters. We found
that in the weak coupling regime the decoherence and relaxation rates are
directly related to the spectral density taken at Rabi or at zero frequency,
depending on what a particular qubit's parameters is fluctuating. This relation
holds also in the presence of weak back-action of the qubit on the fluctuating
environment. In the case of strong back-action, such simple relationship no
longer holds, even if the qubit-SET coupling is small. It does not hold either
in the strong-coupling regime, even in the absence of the back-action. In
addition, we found that our model predicts localization of the qubit in the
strong-coupling regime, resembling that of the spin-boson model.


title: Group-theoretical properties of nilpotent modular categories

abstract:
  We characterize a natural class of modular categories of prime power
Frobenius-Perron dimension as representation categories of twisted doubles of
finite p-groups. We also show that a nilpotent braided fusion category C admits
an analogue of the Sylow decomposition. If the simple objects of C have
integral Frobenius-Perron dimensions then C is group-theoretical. As a
consequence, we obtain that semisimple quasi-Hopf algebras of prime power
dimension are group-theoretical. Our arguments are based on a reconstruction of
twisted group doubles from Lagrangian subcategories of modular categories (this
is reminiscent to the characterization of doubles of quasi-Lie bialgebras in
terms of Manin pairs).


title: Remarks on N_c dependence of decays of exotic baryons

abstract:
  We calculate the N_c dependence of the decay widths of exotic eikosiheptaplet
within the framework of Chral Quark Soliton Model. We also discuss
generalizations of regular baryon representations for arbitrary N_c.


title: Analysis of random Boolean networks using the average sensitivity

abstract:
  In this work we consider random Boolean networks that provide a general model
for genetic regulatory networks. We extend the analysis of James Lynch who was
able to proof Kauffman's conjecture that in the ordered phase of random
networks, the number of ineffective and freezing gates is large, where as in
the disordered phase their number is small. Lynch proved the conjecture only
for networks with connectivity two and non-uniform probabilities for the
Boolean functions. We show how to apply the proof to networks with arbitrary
connectivity $K$ and to random networks with biased Boolean functions. It turns
out that in these cases Lynch's parameter $\lambda$ is equivalent to the
expectation of average sensitivity of the Boolean functions used to construct
the network. Hence we can apply a known theorem for the expectation of the
average sensitivity. In order to prove the results for networks with biased
functions, we deduct the expectation of the average sensitivity when only
functions with specific connectivity and specific bias are chosen at random.


title: Theory of polariton mediated Raman scattering in microcavities

abstract:
  We calculate the intensity of the polariton mediated inelastic light
scattering in semiconductor microcavities. We treat the exciton-photon coupling
nonperturbatively and incorporate lifetime effects in both excitons and
photons, and a coupling of the photons to the electron-hole continuum. Taking
the matrix elements as fitting parameters, the results are in excellent
agreement with measured Raman intensities due to optical phonons resonant with
the upper polariton branches in II-VI microcavities with embedded CdTe quantum
wells.


title:
Decomposition numbers for finite Coxeter groups and generalised
  non-crossing partitions

abstract:
  Given a finite irreducible Coxeter group $W$, a positive integer $d$, and
types $T_1,T_2,...,T_d$ (in the sense of the classification of finite Coxeter
groups), we compute the number of decompositions $c=\si_1\si_2 cdots\si_d$ of a
Coxeter element $c$ of $W$, such that $\si_i$ is a Coxeter element in a
subgroup of type $T_i$ in $W$, $i=1,2,...,d$, and such that the factorisation
is "minimal" in the sense that the sum of the ranks of the $T_i$'s,
$i=1,2,...,d$, equals the rank of $W$. For the exceptional types, these
decomposition numbers have been computed by the first author. The type $A_n$
decomposition numbers have been computed by Goulden and Jackson, albeit using a
somewhat different language. We explain how to extract the type $B_n$
decomposition numbers from results of B\'ona, Bousquet, Labelle and Leroux on
map enumeration. Our formula for the type $D_n$ decomposition numbers is new.
These results are then used to determine, for a fixed positive integer $l$ and
fixed integers $r_1\le r_2\le ...\le r_l$, the number of multi-chains $\pi_1\le
\pi_2\le ...\le \pi_l$ in Armstrong's generalised non-crossing partitions
poset, where the poset rank of $\pi_i$ equals $r_i$, and where the "block
structure" of $\pi_1$ is prescribed. We demonstrate that this result implies
all known enumerative results on ordinary and generalised non-crossing
partitions via appropriate summations. Surprisingly, this result on multi-chain
enumeration is new even for the original non-crossing partitions of Kreweras.
Moreover, the result allows one to solve the problem of rank-selected chain
enumeration in the type $D_n$ generalised non-crossing partitions poset, which,
in turn, leads to a proof of Armstrong's $F=M$ Conjecture in type $D_n$.


title: Electromagnetic polarizabilities and the excited states of the nucleon

abstract:
  The electromagnetic polarizabilities of the nucleon are shown to be
essentially composed of the nonresonant $\alpha_p(E_{0+})=+3.2$,
$\alpha_n(E_{0+})=+4.1$,the $t$-channel $\alpha^t_{p,n}=-\beta^t_{p,n}=+7.6$
and the resonant $\beta_{p,n}(P_{33}(1232))=+8.3$ contributions (in units of
$10^{-4}$fm$^3$. The remaining deviations from the experimental data
$\Delta\alpha_p=1.2\pm 0.6$, $\Delta\beta_p=1.2\mp 0.6$, \Delta\alpha_n=0.8\pm
1.7$ and $\Delta\beta_n=2.0\mp 1.8$ are contributed by a larger number of
resonant and nonresonant processes with cancellations between the
contributions. This result confirms that dominant contributions to the electric
and magnetic polarizabilities may be represented in terms of two-photon
couplings to the $\sigma$-meson having the predicted mass $m_\sigma=666$ MeV
and two-photon width $\Gamma_{\gamma\gamma}=2.6$ keV.


title:
Hecke-Clifford algebras and spin Hecke algebras I: the classical affine
  type

abstract:
  Associated to the classical Weyl groups, we introduce the notion of
degenerate spin affine Hecke algebras and affine Hecke-Clifford algebras. For
these algebras, we establish the PBW properties, formulate the intertwiners,
and describe the centers. We further develop connections of these algebras with
the usual degenerate (i.e. graded) affine Hecke algebras of Lusztig by
introducing a notion of degenerate covering affine Hecke algebras.


title: Towards Minimal Resources of Measurement-based Quantum Computation

abstract:
  We improve the upper bound on the minimal resources required for
measurement-based quantum computation. Minimizing the resources required for
this model is a key issue for experimental realization of a quantum computer
based on projective measurements. This new upper bound allows also to reply in
the negative to the open question about the existence of a trade-off between
observable and ancillary qubits in measurement-based quantum computation.


title: A Spitzer census of the IC 348 nebula

abstract:
  We present a Spitzer based census of the IC 348 nebula and embedded star
cluster. Our Spitzer census supplemented by ground based spectra has added 42
class II T-Tauri sources to the cluster membership and identified ~20 class 0/I
protostars. The population of IC 348 likely exceeds 400 sources after
accounting statistically for unidentified diskless members. Our Spitzer census
of IC 348 reveals a population of protostars that is anti-correlated spatially
with the T-Tauri members, which comprise the centrally condensed cluster around
a B star. The protostars are instead found mostly at the cluster periphery
about 1 pc from the B star and spread out along a filamentary ridge. We find
that the star formation rate in this protostellar ridge is consistent with that
rate which built the exposed cluster while the presence of fifteen cold,
starless, millimeter cores intermingled with this protostellar population
indicates that the IC 348 nebula has yet to finish forming stars. We show that
the IC 348 cluster is of order 3-5 crossing times old, and, as evidenced by its
smooth radial profile and confirmed mass segregation, is likely relaxed. While
it seems apparent that the current cluster configuration is the result of
dynamical evolution and its primordial structure has been erased, our findings
support a model where embedded clusters are built up from numerous smaller
sub-clusters. Finally, the results of our Spitzer census indicate that the
supposition that star formation must progress rapidly in a dark cloud should
not preclude these observations that show it can be relatively long lived.


title:
Non-Equilibrium Josephson and Andreev Current through Interacting
  Quantum Dots

abstract:
  We present a theory of transport through interacting quantum dots coupled to
normal and superconducting leads in the limit of weak tunnel coupling. A
Josephson current between two superconducting leads, carried by first-order
tunnel processes, can be established by non-equilibrium proximity effect. Both
Andreev and Josephson current is suppressed for bias voltages below a threshold
set by the Coulomb charging energy. A $\pi$-transition of the supercurrent can
be driven by tuning gate or bias voltages.


title: Discovery of X-ray emission from the young radio pulsar PSR J1357-6429

abstract:
  We present the first X-ray detection of the very young pulsar PSR J1357-6429
(characteristic age of 7.3 kyr) using data from the XMM-Newton and Chandra
satellites. We find that the spectrum is well described by a power-law plus
blackbody model, with photon index Gamma=1.4 and blackbody temperature kT=160
eV. For the estimated distance of 2.5 kpc, this corresponds to a 2-10 keV
luminosity of about 1.2E+32 erg/s, thus the fraction of the spin-down energy
channeled by PSR J1357-6429 into X-ray emission is one of the lowest observed.
The Chandra data confirm the positional coincidence with the radio pulsar and
allow to set an upper limit of 3E+31 erg/s on the 2-10 keV luminosity of a
compact pulsar wind nebula. We do not detect any pulsed emission from the
source and determine an upper limit of 30% for the modulation amplitude of the
X-ray emission at the radio frequency of the pulsar.


title: Resonant activation in bistable semiconductor lasers

abstract:
  We theoretically investigate the possibility of observing resonant activation
in the hopping dynamics of two-mode semiconductor lasers. We present a series
of simulations of a rate-equations model under random and periodic modulation
of the bias current. In both cases, for an optimal choice of the modulation
time-scale, the hopping times between the stable lasing modes attain a minimum.
The simulation data are understood by means of an effective one-dimensional
Langevin equation with multiplicative fluctuations. Our conclusions apply to
both Edge Emitting and Vertical Cavity Lasers, thus opening the way to several
experimental tests in such optical systems.


title: Quark matter and the astrophysics of neutron stars

abstract:
  Some of the means through which the possible presence of nearly deconfined
quarks in neutron stars can be detected by astrophysical observations of
neutron stars from their birth to old age are highlighted.


title: Some non-braided fusion categories of rank 3

abstract:
  We classify all fusion categories for a given set of fusion rules with three
simple object types. If a conjecture of Ostrik is true, our classification
completes the classification of fusion categories with three simple object
types. To facilitate the discussion we describe a convenient, concrete and
useful variation of graphical calculus for fusion categories, discuss
pivotality and sphericity in this framework, and give a short and elementary
re-proof of the fact that the quadruple dual functor is naturally isomorphic to
the identity.


title: Chandra Observations of Supernova 1987A

abstract:
  We have been monitoring Supernova (SN) 1987A with {\it Chandra X-Ray
Observatory} since 1999. We present a review of previous results from our {\it
Chandra} observations, and some preliminary results from new {\it Chandra} data
obtained in 2006 and 2007. High resolution imaging and spectroscopic studies of
SN 1987A with {\it Chandra} reveal that X-ray emission of SN 1987A originates
from the hot gas heated by interaction of the blast wave with the ring-like
dense circumstellar medium (CSM) that was produced by the massive progenitor's
equatorial stellar winds before the SN explosion. The blast wave is now
sweeping through dense CSM all around the inner ring, and thus SN 1987A is
rapidly brightening in soft X-rays. At the age of 20 yr (as of 2007 January),
X-ray luminosity of SN 1987A is $L_{\rm X}$ $\sim$ 2.4 $\times$ 10$^{36}$ ergs
s$^{-1}$ in the 0.5$-$10 keV band. X-ray emission is described by two-component
plane shock model with electron temperatures of $kT$ $\sim$ 0.3 and 2 keV. As
the shock front interacts with dense CSM all around the inner ring, the X-ray
remnant is now expanding at a much slower rate of $v$ $\sim$ 1400 km s$^{-1}$
than it was until 2004 ($v$ $\sim$ 6000 km s$^{-1}$).


title: Classification of superpotentials

abstract:
  We extend our previous classification of superpotentials of ``scalar
curvature type" for the cohomogeneity one Ricci-flat equations. We now consider
the case not covered in our previous paper, i.e., when some weight vector of
the superpotential lies outside (a scaled translate of) the convex hull of the
weight vectors associated with the scalar curvature function of the principal
orbit. In this situation we show that either the isotropy representation has at
most 3 irreducible summands or the first order subsystem associated to the
superpotential is of the same form as the Calabi-Yau condition for submersion
type metrics on complex line bundles over a Fano K\"ahler-Einstein product.


title: Linkedness and ordered cycles in digraphs

abstract:
  The minimum semi-degree of a digraph D is the minimum of its minimum
outdegree and its minimum indegree. We show that every sufficiently large
digraph D with minimum semi-degree at least n/2 +k-1 is k-linked. The bound on
the minimum semi-degree is best possible and confirms a conjecture of
Manoussakis from 1990. We also determine the smallest minimum semi-degree which
ensures that a sufficiently large digraph D is k-ordered, i.e. that for every
ordered sequence of k distinct vertices of D there is a directed cycle which
encounters these vertices in this order.


title: Curvature and isocurvature perturbations in two-field inflation

abstract:
  We study cosmological perturbations in two-field inflation, allowing for
non-standard kinetic terms. We calculate analytically the spectra of curvature
and isocurvature modes at Hubble crossing, up to first order in the slow-roll
parameters. We also compute numerically the evolution of the curvature and
isocurvature modes from well within the Hubble radius until the end of
inflation. We show explicitly for a few examples, including the recently
proposed model of `roulette' inflation, how isocurvature perturbations affect
significantly the curvature perturbation between Hubble crossing and the end of
inflation.


title:
Geometric Complexity Theory V: On deciding nonvanishing of a generalized
  Littlewood-Richardson coefficient

abstract:
  This article has been withdrawn because it has been merged with the earlier
article GCT3 (arXiv: CS/0501076 [cs.CC]) in the series. The merged article is
now available as:
  Geometric Complexity Theory III: on deciding nonvanishing of a
Littlewood-Richardson Coefficient, Journal of Algebraic Combinatorics, vol. 36,
issue 1, 2012, pp. 103-110. (Authors: Ketan Mulmuley, Hari Narayanan and Milind
Sohoni)
  The new article in this GCT5 slot in the series is:
  Geometric Complexity Theory V: Equivalence between blackbox derandomization
of polynomial identity testing and derandomization of Noether's Normalization
Lemma, in the Proceedings of FOCS 2012 (abstract), arXiv:1209.5993 [cs.CC]
(full version) (Author: Ketan Mulmuley)


title: A schematic model of scattering in PT-symmetric Quantum Mechanics

abstract:
  One-dimensional scattering problem admitting a complex, PT-symmetric
short-range potential V(x) is considered. Using a Runge-Kutta-discretized
version of Schroedinger equation we derive the formulae for the reflection and
transmission coefficients and emphasize that the only innovation emerges in
fact via a complexification of one of the potential-characterizing parameters.


title:
The exact asymptotic of the collision time tail distribution for
  independent Brownian particles with different drifts

abstract:
  In this note we consider the time of the collision $\tau$ for $n$ independent
Brownian motions $X^1_t,...,X_t^n$ with drifts $a_1,...,a_n$, each starting
from $x=(x_1,...,x_n)$, where $x_1<...<x_n$. We show the exact asymptotics of
$P_x(\tau>t) = C h(x)t^{-\alpha}e^{-\gamma t}(1 + o(1))$ as $t\to\infty$ and
identify $C,h(x),\alpha,\gamma$ in terms of the drifts.


title: Ab initio Study of Graphene on SiC

abstract:
  Employing density-functional calculations we study single and double graphene
layers on Si- and C-terminated 1x1-6H-SiC surfaces. We show that, in contrast
to earlier assumptions, the first carbon layer is covalently bonded to the
substrate, and cannot be responsible for the graphene-type electronic spectrum
observed experimentally. The characteristic spectrum of free-standing graphene
appears with the second carbon layer, which exhibits a weak van der Waals
bonding to the underlying structure. For Si-terminated substrate, the interface
is metallic, whereas on C-face it is semiconducting or semimetallic for single
or double graphene coverage, respectively.


title:
Capacity of a Multiple-Antenna Fading Channel with a Quantized Precoding
  Matrix

abstract:
  Given a multiple-input multiple-output (MIMO) channel, feedback from the
receiver can be used to specify a transmit precoding matrix, which selectively
activates the strongest channel modes. Here we analyze the performance of
Random Vector Quantization (RVQ), in which the precoding matrix is selected
from a random codebook containing independent, isotropically distributed
entries. We assume that channel elements are i.i.d. and known to the receiver,
which relays the optimal (rate-maximizing) precoder codebook index to the
transmitter using B bits. We first derive the large system capacity of
beamforming (rank-one precoding matrix) as a function of B, where large system
refers to the limit as B and the number of transmit and receive antennas all go
to infinity with fixed ratios. With beamforming RVQ is asymptotically optimal,
i.e., no other quantization scheme can achieve a larger asymptotic rate. The
performance of RVQ is also compared with that of a simpler reduced-rank scalar
quantization scheme in which the beamformer is constrained to lie in a random
subspace. We subsequently consider a precoding matrix with arbitrary rank, and
approximate the asymptotic RVQ performance with optimal and linear receivers
(matched filter and Minimum Mean Squared Error (MMSE)). Numerical examples show
that these approximations accurately predict the performance of finite-size
systems of interest. Given a target spectral efficiency, numerical examples
show that the amount of feedback required by the linear MMSE receiver is only
slightly more than that required by the optimal receiver, whereas the matched
filter can require significantly more feedback.


title:
On Almost Periodicity Criteria for Morphic Sequences in Some Particular
  Cases

abstract:
  In some particular cases we give criteria for morphic sequences to be almost
periodic (=uniformly recurrent). Namely, we deal with fixed points of
non-erasing morphisms and with automatic sequences. In both cases a
polynomial-time algorithm solving the problem is found. A result more or less
supporting the conjecture of decidability of the general problem is given.


title:
The Radio Emission, X-ray Emission, and Hydrodynamics of G328.4+0.2: A
  Comprehensive Analysis of a Luminous Pulsar Wind Nebula, its Neutron Star,
  and the Progenitor Supernova Explosion

abstract:
  We present new observational results obtained for the Galactic non-thermal
radio source G328.4+0.2 to determine both if this source is a pulsar wind
nebula or supernova remnant, and in either case, the physical properties of
this source. Using X-ray data obtained by XMM, we confirm that the X-ray
emission from this source is heavily absorbed and has a spectrum best fit by a
power law model of photon index=2 with no evidence for a thermal component, the
X-ray emission from G328.4+0.2 comes from a region significantly smaller than
the radio emission, and that the X-ray and radio emission are significantly
offset from each other. We also present the results of a new high resolution (7
arcseconds) 1.4 GHz image of G328.4+0.2 obtained using the Australia Telescope
Compact Array, and a deep search for radio pulsations using the Parkes Radio
Telescope. We find that the radio emission has a flat spectrum, though some
areas along the eastern edge of G328.4+0.2 have a steeper radio spectral index
of ~-0.3. Additionally, we obtain a luminosity limit of the central pulsar of
L_{1400} < 30 mJy kpc^2, assuming a distance of 17 kpc. In light of these
observational results, we test if G328.4+0.2 is a pulsar wind nebula (PWN) or a
large PWN inside a supernova remnant (SNR) using a simple hydrodynamic model
for the evolution of a PWN inside a SNR. As a result of this analysis, we
conclude that G328.4+0.2 is a young (< 10000 years old) pulsar wind nebula
formed by a low magnetic field (<10^12 G) neutron star born spinning rapidly
(<10 ms) expanding into an undetected SNR formed by an energetic (>10^51 ergs),
low ejecta mass (M < 5 Solar Masses) supernova explosion which occurred in a
low density (n~0.03 cm^{-3}) environment.


title: Three Particle Correlations from STAR

abstract:
  Two-particle correlations have shown modification to the away-side shape in
central Au+Au collisions relative to $pp$, d+Au and peripheral Au+Au
collisions. Different scenarios can explain this modification including: large
angle gluon radiation, jets deflected by transverse flow, path length dependent
energy loss, Cerenkov gluon radiation of fast moving particles, and conical
flow generated by hydrodynamic Mach-cone shock-waves. Three-particle
correlations have the power to distinguish the scenarios with conical emission,
conical flow and Cerenkov radiation, from other scenarios. In addition, the
dependence of the observed shapes on the $p_T$ of the associated particles can
be used to distinguish conical emission from a sonic boom (Mach-cone) and from
QCD-Cerenkov radiation. We present results from STAR on 3-particle azimuthal
correlations for a high $p_T$ trigger particle with two softer particles.
Results are shown for $pp$, d+Au and high statistics Au+Au collisions at
$\sqrt{s_{NN}}$=200 GeV. An important aspect of the analysis is the subtraction
of combinatorial backgrounds. Systematic uncertainties due to this subtraction
and the flow harmonics v2 and v4 are investigated in detail. The implications
of the results for the presence or absence of conical flow from Mach-cones are
discussed.


title: The Return of a Static Universe and the End of Cosmology

abstract:
  We demonstrate that as we extrapolate the current $\Lambda$CDM universe
forward in time, all evidence of the Hubble expansion will disappear, so that
observers in our "island universe" will be fundamentally incapable of
determining the true nature of the universe, including the existence of the
highly dominant vacuum energy, the existence of the CMB, and the primordial
origin of light elements. With these pillars of the modern Big Bang gone, this
epoch will mark the end of cosmology and the return of a static universe. In
this sense, the coordinate system appropriate for future observers will perhaps
fittingly resemble the static coordinate system in which the de Sitter universe
was first presented.


title:
Dark Matter annihilation in Draco: new considerations on the expected
  gamma flux

abstract:
  A new estimation of the gamma-ray flux that we expect to detect from SUSY
dark matter annihilation from the Draco dSph is presented using the DM density
profiles compatible with the latest observations. This calculation takes also
into account the important effect of the Point Spread Function (PSF) of the
telescope. We show that this effect is crucial in the way we will observe and
interpret a possible signal detection. Finally, we discuss the prospects to
detect a possible gamma signal from Draco for MAGIC and GLAST.


title: Magnetohydrodynamic Rebound Shocks of Supernovae

abstract:
  We construct magnetohydrodynamic (MHD) similarity rebound shocks joining
`quasi-static' asymptotic solutions around the central degenerate core to
explore an MHD model for the evolution of random magnetic field in supernova
explosions. This provides a theoretical basis for further studying synchrotron
diagnostics, MHD shock acceleration of cosmic rays, and the nature of intense
magnetic field in compact objects. The magnetic field strength in space
approaches a limiting ratio, that is comparable to the ratio of the ejecta mass
driven out versus the progenitor mass, during this self-similar rebound MHD
shock evolution. The intense magnetic field of the remnant compact star as
compared to that of the progenitor star is mainly attributed to both the
gravitational core collapse and the radial distribution of magnetic field.


title:
Are There Mach Cones in Heavy Ion Collisions? Three-Particle
  Correlations from STAR

abstract:
  We present results from STAR on 3-particle azimuthal correlations for a
$3<p_T<4$ GeV/c trigger particle with two softer $1<p_T<2$ GeV/c particles.
Results are shown for pp, d+Au and high statistics Au+Au collisions at
$\sqrt{s_{NN}}=200 GeV$. We observe a 3-particle correlation in central Au+Au
collisions which may indicate the presence of conical emission. In addition,
the dependence of the observed signal angular position on the $p_T$ of the
associated particles can be used to distinguish conical flow from simple
QCD-\v{C}erenkov radiation. An important aspect of the analysis is the
subtraction of combinatorial backgrounds. Systematic uncertainties due to this
subtraction and the flow harmonics $v_2$ and $v_4$ are investigated in detail.


title: Exploring First Stars Era with GLAST

abstract:
  Cosmic infrared background (CIB) includes emissions from objects inaccessible
to current telescopic studies, such as the putative Population III, the first
stars. Recently, strong direct evidence for significant CIB levels produced by
the first stars came from CIB fluctuations discovered in deep Spitzer images.
Such CIB levels should have left a unique absorption feature in the spectra of
high-z GRBs and blazars as suggested in [4]. This is observable with GLAST
sources at z>2 and measuring this absorption will give important information on
energetics and constituents of the first stars era.


title:
Correlated modulation between the redshifted Fe K alpha line and the
  continuum emission in NGC 3783

abstract:
  It has been suggested that X-ray observations of rapidly variable Seyfert
galaxies may hold the key to probe the gas orbital motions in the innermost
regions of accretion discs around black holes and, thus, trace flow patterns
under the effect of the hole strong gravitational field. We explore this
possibility analizing XMM-Newton observations of the seyfert 1 galaxy NGC 3783.
A detiled time-resolved spectral analysis is performed down to the shortest
possible time-scales (few ks) using "excess maps" and cross-correlating light
curves in different energy bands. In addition to a constant core of the Fe K
alpha line, we detected a variable and redshifted Fe K alpha emission feature
between 5.3-6.1 keV. The line exhibits a modulation on a time-scale of 27 ks
that is similar to and in phase with a modulation of the 0.3-10 keV source
continuum. The time-scale of the correlated variability of the redshifted Fe
line and continuum agrees with the local dynamical time-scale of the accretion
disc at 10 r_g around a black hole of 10^7 M_sun. Given the shape of the
redshfted line emission and the overall X-ray variability pattern, the line is
likely to arise from the relativistic region near the black hole.


title: Isotopic Effects in Nuclear Reactions at Relativistic Energies

abstract:
  A systematic study of isotopic effects in the break-up of projectile
spectators at relativistic energies has been performed at the GSI laboratory
with the ALADiN spectrometer coupled to the LAND neutron detector. Besides a
primary beam of 124Sn, also secondary beams of 124La and 107Sn produced at the
FRS fragment separator have been used in order to extend the range of isotopic
compositions. The gross properties of projectile fragmentation are very similar
for all the studied systems but specific isotopic effects have been observed in
both neutron and charged particle production. The breakup temperatures obtained
from the double ratios of isotopic yields have been extracted and compared with
the limiting-temperature expectation.


title:
Einstein vs Maxwell: Is gravitation a curvature of space, a field in
  flat space, or both?

abstract:
  Starting with a field theoretic approach in Minkowski space, the
gravitational energy momentum tensor is derived from the Einstein equations in
a straightforward manner. This allows to present them as {\it acceleration
tensor} = const. $\times$ {\it total energy momentum tensor}. For flat space
cosmology the gravitational energy is negative and cancels the material energy.
In the relativistic theory of gravitation a bimetric coupling between the
Riemann and Minkowski metrics breaks general coordinate invariance. The case of
a positive cosmological constant is considered. A singularity free version of
the Schwarzschild black hole is solved analytically. In the interior the
components of the metric tensor quickly die out, but do not change sign,
leaving the role of time as usual. For cosmology the $\Lambda$CDM model is
covered, while there appears a form of inflation at early times. Here both the
total energy and the zero point energy vanish.