title: Perturbation of essential spectra of exterior elliptic problems

abstract:
  For a second-order strongly elliptic differential operator on an exterior
domain in R^n it is known from works of Birman and Solomiak that a change of
the boundary condition from the Dirichlet condition to an elliptic Neumann or
Robin condition leaves the essential spectrum unchanged, in such a way that the
spectrum of the difference between the inverses satisfies a Weyl-type
asymptotic formula. We show that one can augment, but not diminish, the
essential spectrum by imposition of other Neumann-type non-elliptic boundary
conditions. - The results are extended to 2m-order operators, where it is shown
that for any selfadjoint realization defined by an elliptic normal boundary
condition (other than the Dirichlet condition), one can augment the essential
spectrum at will by adding a suitable operator to the mapping from free
Diriclet data to Neumann data. We here also show an extension of the spectral
asymptotics formula for the difference between inverses of elliptic problems. -
The proofs rely on Krein-type formulas for differences between inverses, and
cutoff techniques, combined with results on singular Green operators and their
spectral asymptotics.


title: On the structure of left and right F-, SM- and E-quasigroups

abstract:
  It is proved that any left F-quasigroup is isomorphic to the direct product
of a left F-quasigroup with a unique idempotent element and isotope of a
special form of a left distributive quasigroup. The similar theorems are proved
for right F-quasigroups, left and right SM- and E-quasigroups. Information on
simple quasigroups from these quasigroup classes is given, for example, finite
simple F-quasigroup is a simple group or a simple medial quasigroup. It is
proved that any left F-quasigroup is isotopic to the direct product of a group
and a left S-loop. Some properties of loop isotopes of F-quasigroups (including
M-loops) are pointed out. A left special loop is an isotope of a left
F-quasigroup if and only if this loop is isomorphic the direct product of a
group and a left S-loop (this is an answer to Belousov "1a", problem). Any left
FESM-quasigroup is isotopic to the direct product of an abelian group and a
left S-loop (this is an answer to Kinyon-Phillips 2.8(2) problem). New proofs
of some known results on the structure of commutative Moufang loops are
presented.


title:
Moments, cumulants and diagram formulae for non-linear functionals of
  random measures

abstract:
  This survey provides a unified discussion of multiple integrals, moments,
cumulants and diagram formulae associated with functionals of completely random
measures. Our approach is combinatorial, as it is based on the algebraic
formalism of partition lattices and M\"obius functions. Gaussian and Poisson
measures are treated in great detail. We also present several combinatorial
interpretations of some recent CLTs involving sequences of random variables
belonging to a fixed Wiener chaos.


title: On Static n-body Configurations in Relativity

abstract:
  The static n-body problem of General Relativity states that there are, under
a reasonable energy condition, no static $n$-body configurations for $n > 1$,
provided the configuration of the bodies satisfies a suitable separation
condition. In this paper we solve this problem in the case that there exists a
closed, noncompact, totally geodesic surface disjoint from the bodies. This
covers the situation where the configuration has a reflection symmetry across a
noncompact surface disjoint from the bodies.


title:
High Temperature Cuprate-Like Superconductivity at Surfaces and
  Interfaces

abstract:
  The realization of high-transition-temperature superconductivity (HTSC)
confined to nanometre-sized interfaces has been a long-standing goal because of
potential applications and the opportunity to study quantum phenomena in
reduced dimensions. Here we discuss HTSC at free surfaces, interfaces, and
nanoscale cluster surfaces, and show that the percolative self-organized model
of bulk HTSC also gives an excellent description of HTSC in
quasi-two-dimensional contexts.


title: Batch means and spectral variance estimators in Markov chain Monte Carlo

abstract:
  Calculating a Monte Carlo standard error (MCSE) is an important step in the
statistical analysis of the simulation output obtained from a Markov chain
Monte Carlo experiment. An MCSE is usually based on an estimate of the variance
of the asymptotic normal distribution. We consider spectral and batch means
methods for estimating this variance. In particular, we establish conditions
which guarantee that these estimators are strongly consistent as the simulation
effort increases. In addition, for the batch means and overlapping batch means
methods we establish conditions ensuring consistency in the mean-square sense
which in turn allows us to calculate the optimal batch size up to a constant of
proportionality. Finally, we examine the empirical finite-sample properties of
spectral variance and batch means estimators and provide recommendations for
practitioners.


title: The Beilinson-Drinfeld Grassmannian and symplectic knot homology

abstract:
  Seidel-Smith and Manolescu constructed knot homology theories using
symplectic fibrations whose total spaces were certain varieties of matrices.
These knot homology theories were associated to $SL(n) $ and tensor products of
the standard and dual representations. In this paper, we place their geometric
setups in a natural, general framework. For any complex reductive group and any
sequence of minuscule dominant weights, we construct a fibration of affine
varieties over a configuration space. The middle cohomology of these varieties
is isomorphic to the space of invariants in the corresponding tensor product of
representations. Our construction uses the Beilinson-Drinfeld Grassmannian and
the geometric Satake correspondence.


title: Are AGN the Best Factories for High Energy Particles and Photons?

abstract:
  The main properties of AGN are reviewed, focussing on the accretion process
and on the question of whether AGN are the best factories of ultra high energy
particles and photons. I recall the large differences between the
accretion/ejection flows in strong and weak accretors, and I conclude that,
since low luminosity AGN and even "dormant" massive black holes in nuclei of
galaxies are powering strong confined magnetized jets able to accelerate high
energy particles, and are present in a large proportion of galaxies, they might
be better potential sources of high energy particles and photons than luminous
AGN and powerful radio galaxies.


title:
Nonanalytic paramagnetic response of itinerant fermions away and near a
  ferromagnetic quantum phase transition

abstract:
  We study nonanalytic paramagnetic response of an interacting Fermi system
both away and in the vicinity of a ferromagnetic quantum phase transition
(QCP). Previous studies found that (i) the spin susceptibility scales linearly
with either the temperature $T$ or magnetic field H in the weak-coupling
regime; (ii) the interaction in the Cooper channel affects this scaling via
logarithmic renormalization of prefactors of the $T$, |H| terms, and may even
reverse the signs of these terms at low enough energies. We show that Cooper
renormalization becomes effective only at very low energies, which get even
smaller near a QCP. However,even in the absence of such renormalization,
generic (non-Cooper) higher-order processes may also inverse the sign of T,|H|
scaling. We derive the thermodynamic potential as a function of magnetization
and show that it contains, in addition to regular terms, a non-analytic |M|^3
term, which becomes M^4/T at finite $T$. We show that regular (M^2, M^4, ...)
terms originate from fermions with energies of order of the bandwidth, while
the non-analytic term comes from low-energy fermions. We consider the vicinity
of a ferromagnetic QCP by generalizing the Eliashberg treatment of the
spin-fermion model to finite magnetic field, and show that the |M|^3 term
crosses over to a non-Fermi-liquid form |M|^{7/2} near a QCP. The prefactor of
the |M|^{7/2} term is negative, which indicates that the system undergoes a
first-order rather than a continuous transition to ferromagnetism. We compare
two scenarios of the breakdown of a continuous QCP: a first-order instability
and a spiral phase. In a model with a long-range interaction in the spin
channel, we show that the first-order transition occurs before the spiral
instability.


title: The Euler adic dynamical system and path counts in the Euler graph

abstract:
  We give a formula for generalized Eulerian numbers, prove monotonicity of
sequences of certain ratios of the Eulerian numbers, and apply these results to
obtain a new proof that the natural symmetric measure for the Bratteli-Vershik
dynamical system based on the Euler graph is the unique fully supported
invariant ergodic Borel probability measure. Key ingredients of the proof are a
two-dimensional induction argument and a one-to-one correspondence between most
paths from two vertices at the same level to another vertex.


title:
How to compute the length of a geodesic on a Riemannian manifold with
  small error in arbitrary Sobolev norms

abstract:
  We compute the length of geodesics on a Riemannian manifold by regular
polynomial interpolation of the global solution of the eikonal equation related
to the line element $ds^2=g_{ij}dx^idx^j$ of the manifold. Our algorithm
approximates the length functional in arbitrarily strong Sobolev norms. Error
estimates are obtained where the geometric information is used. It is pointed
out how the algorithm can be used to get accurate approximation of solutions of
parabolic partial differential equations leading obvious applications to
finance and physics.


title:
Ballistic deposition on deterministic fractals: On the observation of
  discrete scale invariance

abstract:
  The growth of ballistic aggregates on deterministic fractal substrates is
studied by means of numerical simulations. First, we attempt the description of
the evolving interface of the aggregates by applying the well-established
Family-Vicsek dynamic scaling approach. Systematic deviations from that
standard scaling law are observed, suggesting that significant scaling
corrections have to be introduced in order to achieve a more accurate
understanding of the behavior of the interface. Subsequently, we study the
internal structure of the growing aggregates that can be rationalized in terms
of the scaling behavior of frozen trees, i.e., structures inhibited for further
growth, lying below the growing interface. It is shown that the rms height
($h_{s}$) and width ($w_{s}$) of the trees of size $s$ obey power laws of the
form $h_{s} \propto s^{\nu_{\parallel}}$ and $w_{s} \propto s^{\nu_{\perp}}$,
respectively. Also, the tree-size distribution ($n_{s}$) behaves according to
$n_{s}\sim s^{-\tau}$. Here, $\nu_{\parallel}$ and $\nu_{\perp}$ are the
correlation length exponents in the directions parallel and perpendicular to
the interface, respectively. Also, $\tau$ is a critical exponent. However, due
to the interplay between the discrete scale invariance of the underlying
fractal substrates and the dynamics of the growing process, all these power
laws are modulated by logarithmic periodic oscillations. The fundamental
scaling ratios, characteristic of these oscillations, can be linked to the
(spatial) fundamental scaling ratio of the underlying fractal by means of
relationships involving critical exponents.


title: Efficient Raman amplification into the PetaWatt regime

abstract:
  Raman amplification of a short laser pulse off a long laser beam has been
demonstrated successfully for moderate probe intensities ($\sim 10^{16}$
W/cm$^2$) and widths ($\sim 50$ micron). However, truly competitive intensities
can only be reached if the amplification process is carried out at much higher
probe intensities ($10^{17}-10^{18}$ W/cm$^2$ after amplification) and widths
(1-10 mm). In this paper we examine the opportunities and challenges provided
by this regime through the first 2-dimensional particle-in-cell simulations
using wide pulses. A parameter window is identified in which a 10 TW, 600
$\mu$m wide, 25 ps long laser pulse can be efficiently amplified to 2 PW peak
intensity.


title: Towards A Possible Charge-Kondo effect in Optical Lattices

abstract:
  The Kondo effect underpins a large body of recent developments in the physics
of $d$- and $f$-band compounds. Although its {\it charge} analog is a rarity in
solids, the recent observations of the charge Kondo effect and the consequent
rise in superconducting T$_c$ encourage a search for other accessible systems.
Motivated by the possibility of wilfully tuning the {\it sign} of the
inter-electronic interaction in optical lattices, we study conditions for the
elusive {\it charge Kondo liquid} (CKL) state to manifest. We propose that a
combination of Feshbach resonances and sequentially controlled laser pulses may
produce the CKL. We show that the CKL is {\it never} a stable ground state,
appearing only when the ordered ground states are destabilized. Finally, we
discuss interesting analogies with nuclear matter.


title: On free associative algebras linearly graded by finite groups

abstract:
  As an instance of a linear action of a Hopf algebra on a free associative
algebra, we consider finite group gradings of a free algebra induced by
gradings on the space spanned by the free generators. The homogeneous component
corresponding to the identity of the group is a free subalgebra which is graded
by the usual degree. We look into its Hilbert series and prove that it is a
rational function by giving an explicit formula. As an application, we show
that, under suitable conditions, this subalgebra is finitely generated if and
only if the grading on the base vector space is trivial.


title:
The data mining: An analysis of 20 eclipsing binary light-curves
  observed by the INTEGRAL/OMC

abstract:
  Twenty eclipsing binaries were selected for an analysis from a huge database
of observations made by the INTEGRAL/OMC camera. The photometric data were
processed and analyzed, resulting in a first light-curve study of these
neglected eclipsing binaries. Most of the selected systems are the detached
ones. The system ET Vel was discovered to be an eccentric one. Due to missing
spectroscopic study of these stars, further detailed analyses are still needed.


title: Six White Dwarfs with Circumstellar Silicates

abstract:
  Spitzer Space Telescope spectra reveal 10 micron silicate emission from
circumstellar dust orbiting six externally-polluted white dwarfs. Micron-size
glasses with an olivine stoichiometry can account for the distinctively broad
wings that extend to 12 microns; these particles likely are produced by
tidal-disruption of asteroids. The absence of infrared PAH features is
consistent with a scenario where extrasolar rocky planets are assembled from
carbon-poor solids.


title: Hawking Radiation and Quantum Anomaly in AdS2/CFT1 Correspondence

abstract:
  In order to understand a boundary description of Hawking radiation in the
AdS/CFT correspondence, we investigate the trace anomaly method in AdS$_2$
space. In this method, Hawking radiation is derived from the trace anomaly of
the energy-momentum tensor in the bulk. We find a correspondence between the
energy-momentum tensor and a composite operator in CFT$_1$ and understand the
anomalous properties of the energy-momentum tensor in terms of this composite
operator. By using this correspondence, we reproduce Hawking radiation from the
boundary description. In addition, we find a correspondence between higher-spin
currents in the bulk and composite operators in the boundary.


title: Banach $\widetilde{\mathbb C}$-algebras

abstract:
  We study Banach $\widetilde{\mathbb C}$-algebras, i.e., complete
ultra-pseudo-normed algebras over the ring $\widetilde{\mathbb C}$ of Colombeau
generalized complex numbers. We develop a spectral theory in such algebras. We
show by explicit examples that important parts of classical Banach algebra
theory do not hold for general Banach $\widetilde{\mathbb C}$-algebras and
indicate a particular class of Banach $\widetilde{\mathbb C}$-algebras that
overcomes these limitations to a large extent. We also investigate C*-algebras
over $\widetilde{\mathbb C}$.


title: Dimension six FCNC operators and top production at the LHC

abstract:
  In this work we calculate the effects of the electroweak flavour changing
neutral currents dimension six effective operators on single top production at
the LHC. These results are then combined with previous ones we have obtained
for the strong sector. This allow us, for the first time, to perform a combined
analysis of flavour changing neutral currents in top production with all
contributing dimension six operators. Finally, we study the feasibility of
their observation and characterization both at the Tevatron and at the LHC.


title: Spin Orientation of Holes in Quantum Wells

abstract:
  This paper reviews the spin orientation of spin-3/2 holes in quantum wells.
We discuss the Zeeman and Rashba spin splitting in hole systems that are
qualitatively different from their counterparts in electron systems. We show
how a systematic understanding of the unusual spin-dependent phenomena in hole
systems can be gained using a multipole expansion of the spin density matrix.
As an example we discuss spin precession in hole systems that can give rise to
an alternating spin polarization. Finally, we discuss the qualitatively
different regimes of hole spin polarization decay in clean and dirty samples.


title:
Impact of low-frequency p modes on the inversions of the internal
  rotation of the Sun

abstract:
  We used the m-averaged spectrum technique ("collapsogram") to extract the
low-frequency solar p-mode parameters of low- and intermediate-angular degrees
(l \leq 35) in long time series of GONG and MDI observations. Rotational
splittings and central frequencies have been measured down to ~850\muHz,
including predicted modes which have not been measured previously. Both GONG
and MDI frequency splitting data sets were numerically inverted to extract the
internal solar rotation rate. The impact of the very low-frequency observables
and the differences between GONG and MDI data sets on the inversion results are
also analyzed.


title: On the violation of the CHSH network model inequality

abstract:
  In the present paper it is demonstrated that the quantum correlation (2-dim
unitary parameter vectors) can be arbitrarily close approximated with a local
hidden variables model. Moreover, the CHSH inequality can be violated with the
present model. This does not conclusively demonstrate that locality and
causality can be restored to quantum mechanics. However, it does show that an
experimental search for local hidden causality need not be fruitless
beforehand.


title: On a Structure of the Set of Differential Games Values

abstract:
  In this paper the set of value functions of all-possible zero-sum
differential games with terminal payoff is characterized. The necessary and
sufficient condition for a given function to be a value of some differential
game with terminal payoff is obtained.


title: Survival of branching random walks in random environment

abstract:
  We study survival of nearest-neighbour branching random walks in random
environment (BRWRE) on ${\mathbb Z}$. A priori there are three different
regimes of survival: global survival, local survival, and strong local
survival. We show that local and strong local survival regimes coincide for
BRWRE and that they can be characterized with the spectral radius of the first
moment matrix of the process. These results are generalizations of the
classification of BRWRE in recurrent and transient regimes. Our main result is
a characterization of global survival that is given in terms of Lyapunov
exponents of an infinite product of i.i.d. $2\times 2$ random matrices.


title: Factor analysis of the long gamma-ray bursts

abstract:
  We study statistically 197 long gamma-ray bursts, detected and measured in
detail by the BATSE instrument of the Compton Gamma-Ray Observatory. In the
sample 10 variables, describing for any burst the time behavior of the spectra
and other quantities, are collected. The factor analysis method is used to find
the latent random variables describing the temporal and spectral properties of
GRBs. The application of this particular method to this sample indicates that
five factors and the $\REpk$ spectral variable (the ratio of peak energies in
the spectrum) describe the sample satisfactorily. Both the pseudo-redshifts
inferred from the variability, and the Amati-relation in its original form, are
disfavored.


title:
A note on conductivity and charge diffusion in holographic flavour
  systems

abstract:
  We analyze the charge diffusion and conductivity in a Dp/Dq holographic setup
that is dual to a supersymmetric Yang-Mills theory in p+1 dimensions with N_f<<
N_c flavour degrees of freedom at finite temperature and nonvanishing U(1)
baryon number chemical potential. We provide a new derivation of the results
that generalize the membrane paradigm to the present context. We perform a
numerical analysis in the particular case of the D3/D7 flavor system. The
results obtained support the validity of the Einstein relation at finite
chemical potential.


title:
On presentation of lightning flash in thundercloud as collective
  spontaneous radiation (superradiation) pulse

abstract:
  In this paper we conjecture that some specific properties of an electroactive
region of thunderclouds play the major role in an initiation of a lightning
flash. The electroactive region is modeled here as a quantum two-level system
of oxygen molecules which are assumed to have two (ground and excited) states,
where transitions from ground to excited states come as a result of
micro-discharges between ice particles. In this case lightning flash
corresponds to the pulse of collective spontaneous radiation caused by the
deexcitations of excited oxygen molecules from metastable state into ground
state.


title: Relativistic Quark-Model Results for Baryon Ground and Resonant States

abstract:
  Latest results from a study of baryon ground and resonant states within
relativistic constituent quark models are reported. After recalling some
typical spectral properties, the description of ground states, especially with
regard to the nucleon and hyperon electromagnetic structures, is addressed. In
the following, recent covariant predictions for pion, eta, and kaon partial
decay widths of light and strange baryon resonances below 2 GeV are summarized.
These results exhibit a characteristic pattern that is distinct from
nonrelativistic or relativized decay studies performed so far. Together with a
detailed analysis of the spin, flavor, and spatial structures of the wave
functions, it supports a new and extended classification scheme of baryon
ground and resonant states into SU(3) flavor multiplets.


title:
The X-Ray Environment During the Epoch of Terrestrial Planet Formation:
  Chandra Observations of h Persei

abstract:
  We describe Chandra/ACIS-I observations of the massive ~ 13--14 Myr-old
cluster, h Persei, part of the famous Double Cluster (h and chi Persei) in
Perseus. Combining the list of Chandra-detected sources with new optical/IR
photometry and optical spectroscopy reveals ~ 165 X-ray bright stars with V <
23. Roughly 142 have optical magnitudes and colors consistent with cluster
membership. The observed distribution of Lx peaks at Lx ~ 10^30.3 ergs/s and
likely traces the bright edge of a far larger population of ~ 0.4--2 Msun X-ray
active stars. From a short list of X-ray active stars with IRAC 8 micron excess
from warm, terrestrial-zone dust, we derive a maximum X-ray flux incident on
forming terrestrial planets. Although there is no correlation between X-ray
activity and IRAC excess, the fractional X-ray luminosity correlates with
optical colors and spectral type. By comparing the distribution of Lx/L* vs.
spectral type and V-I in h Per with results for other 1--100 Myr-old clusters,
we show that stars slightly more massive than the Sun (> 1.5 Msun) fall out of
X-ray saturation by ~ 10--15 Myr. Changes in stellar structure for > 1.5 Msun
stars likely play an important role in this decline of X-ray emission.


title:
Revisiting the formation History of the minor-axis dust lane galaxy
  NGC1947

abstract:
  In this paper we present a detailed study of the peculiar early-type galaxy
NGC1947. The main goal of this work is to constrain the dynamical status and
the formation history of NGC1947 by comparing the observed properties with the
predictions derived from different galaxy formation scenarios. To this aim, we
derived the photometric and kinematical properties of NGC1947. Due to the
presence of an extended dust-lane, which crosses the galaxy center along the
photometric minor axis, we used near-infrared images (J and K bands) to derive
an accurate analysis of the stellar light distribution. Optical images (in the
V and R bands) are used to derive the color profiles and color maps to study
the structure of the dust-lane. The observed kinematics confirm the presence of
two components with decoupled angular momentum: gas and dust rotate along the
minor axis, while the rotation velocities of the stars are observed along the
major axis. The complex structure observed in NGC1947 support the hypothesis
that some kind of interactions happened in the evolution of this object. We
analyzed two alternatives: a merging process and an accretion event. We
discussed how the observed properties strongly suggest that the decoupled ring
of gas and dust have been accreted from outside.


title: The spectrum of charmonium in the Resonance-Spectrum Expansion

abstract:
  We argue that the resonance-like structures Y(4260)
(arXiv:hep-ex/0506081,arXiv:0707.2541), Y(4360), Y(4660) (arXiv:0707.3699) and
Y(4635) (arXiv:0807.4458), which were recently reported to have been observed
in experiment, are non-resonant manifestations of the Regge zeros that appear
in the production amplitude of the Resonance-Spectrum Expansion. Charmonium
c-cbar states are visible on the slopes of these enhancements.


title: Orthogonal bundles over curves in characteristic two

abstract:
  Let X be a smooth projective curve of genus g \geq 2 defined over a field of
characteristic two. We give examples of stable orthogonal bundles with unstable
underlying vector bundles and use them to give counterexamples to Behrend's
conjecture on the canonical reduction of principal G-bundles for G= SO(n) with
n \geq 7.


title:
Current and Shot Noise Measurements in a Carbon Nanotube-Based Spin
  Diode

abstract:
  Low-temperature measurements of asymmetric carbon nanotube (CNT) quantum dots
are reported. The CNTs are end-contacted with one ferromagnetic and one
normal-metal electrode. The measurements show a spin-dependent rectification of
the current caused by the asymmetry of the device. This rectification occurs
for gate voltages for which the normal-metal lead is resonant with a level of
the quantum dot. At the gate voltages at which the current is at the maximum
current, a significant decrease in the current shot noise is observed.


title: Black Hole Partition Function using Hybrid Formalism of Superstrings

abstract:
  The type IIA superstring partition function Z_IIA on the euclidean attractor
geometry AdS_2 x S^2 x CY_3, computes the modified elliptic genus Z_BH of the
associated black hole. The hybrid formalism of superstrings defined as a
conformally invariant sigma model on the coset supermanifold
PSU(1,1|2)/U(1)xU(1), together with Calabi-Yau and chiral boson CFTs, is used
to calculate Z_IIA. The sigma model action on AdS_2 x S^2 is explicitly written
in U(1)xU(1) invariant variables. The N=2 generators of AdS_2 x S^2 x CY_3 are
enlarged and embedded in an N=4 topological algebra. The world sheet
superconformal invariance is then used to construct a nilpotent BRST operator,
in contrast to the kappa symmetry analysis used by Beasely et. al. in
hep-th/0608021. The sigma model action is explicitly shown to be closed under
this BRST operator. Localization arguments are then used to deform the world
sheet path integral with the addition of a BRST exact term, where,
contributions arise only from the center of AdS_2 and, the north and south
poles of S^2. This leads to the OSV result Z_BH = Z_IIA = |Z_top|^2, where
|Z_top|^2 is the square of the topological string partition function.


title:
Unitarizable representations and fixed points of groups of biholomorphic
  transformations of operator balls

abstract:
  We show that the open unit ball of the space of operators from a finite
dimensional Hilbert space into a separable Hilbert space (we call it "operator
ball") has a restricted form of normal structure if we endow it with a
hyperbolic metric (which is an analogue of the standard hyperbolic metric on
the unit disc in the complex plane). We use this result to get a fixed point
theorem for groups of biholomorphic automorphisms of the operator ball. The
fixed point theorem is used to show that a bounded representation in a
separable Hilbert space which has an invariant indefinite quadratic form with
finitely many negative squares is unitarizable (equivalent to a unitary
representation). We apply this result to find dual pairs of invariant subspaces
in Pontryagin spaces. In the appendix we present results of Itai Shafrir about
hyperbolic metrics on the operator ball.


title: Fast ignition of fusion targets by laser-driven electrons

abstract:
  We present hybrid PIC simulations of fast electron transport and energy
deposition in pre-compressed fusion targets, taking full account of collective
magnetic effects and the hydrodynamic response of the background plasma.
Results on actual ignition of an imploded fast ignition configuration are shown
accounting for the increased beam divergence found in recent experiments [J.S.
Green et al., Phys. Rev. Lett. 100, 015003 (2008)] and the reduction of the
electron kinetic energy due to profile steepening predicted by advanced PIC
simulations [B. Chrisman et al. Phys. Plasmas 15, 056309 (2008)]. Target
ignition is studied as a function of injected electron energy, distance of
cone-tip to dense core, initial divergence and kinetic energy of the
relativistic electron beam. We found that beam collimation reduces
substantially the ignition energies of the cone-guided fuel configuration
assumed here.


title: A symplectic integration method for elastic filaments

abstract:
  A new method is proposed for integrating the equations of motion of an
elastic filament. In the standard finite-difference and finite-element
formulations the continuum equations of motion are discretized in space and
time, but it is then difficult to ensure that the Hamiltonian structure of the
exact equations is preserved. Here we discretize the Hamiltonian itself,
expressed as a line integral over the contour of the filament. This discrete
representation of the continuum filament can then be integrated by one of the
explicit symplectic integrators frequently used in molecular dynamics. The
model systematically approximates the continuum partial differential equations,
but has the same level of computational complexity as molecular dynamics and is
constraint free. Numerical tests show that the algorithm is much more stable
than a finite-difference formulation and can be used for high aspect ratio
filaments, such as actin.


title: Non-steady Accretion in Protostars

abstract:
  Observations indicate that mass accretion rates onto low-mass protostars are
generally lower than the rates of infall to their disks; this suggests that
much of the protostellar mass must be accreted during rare, short outbursts of
rapid accretion. We explore when protostellar disk accretion is likely to be
highly variable. While constant $\alpha$ disks can in principle adjust their
accretion rates to match infall rates, protostellar disks are unlikely to have
constant $\alpha$. In particular we show that neither models with angular
momentum ransport due solely to the magnetorotational instability (MRI) nor
ravitational instability (GI) are likely to transport disk mass at rotostellar
infall rates over the large range of radii needed to move infalling envelope
material down to the central protostar. We show that the MRI and GI are likely
to combine to produce outbursts of rapid accretion starting at a few AU. Our
analysis is consistent with the time-dependent models of Armitage, Livio, &
Pringle (2001) and agrees with our observational study of the outbursting
object FU Ori.


title:
Compositions of projections in Banach spaces and relations between
  approximation properties

abstract:
  A necessary and sufficient condition for existence of a Banach space with a
finite dimensional decomposition but without the $\pi$-property in terms of
norms of compositions of projections is found.


title:
The representation category of any compact group is the bimodule
  category of a II_1 factor

abstract:
  We prove that given any compact group G, there exists a minimal action of G
on a II_1 factor M such that the bimodule category of the fixed-point II_1
factor M^G is naturally equivalent with the representation category of G. In
particular, all subfactors of M^G with finite Jones index can be described
explicitly.


title:
Comment on "The GSI method for studying neutrino mass differences - For
  Pedestrians"

abstract:
  It has been suggested that the reported temporal oscillations in the weak
decay of H-like ions circulating in the GSI storage ring may be accounted for
by interference between two different momentum components of the wave function
of the parent ions. In that model, the interference is said to come about
through coupling of those two momentum components to the two mass components in
the wave function of the electron neutrino in the decayed state. I show here
that quantum mechanics allows no such interference to contribute to the
reported oscillation of the decay rate. The central issue is that the storage
ring is a million times too small to allow the parent ion's wave function to
produce the needed interference effect. This note supersedes earlier arXiv
postings that were less general and less rigorous.


title: Combinatorics of Tripartite Boundary Connections for Trees and Dimers

abstract:
  A grove is a spanning forest of a planar graph in which every component tree
contains at least one of a special subset of vertices on the outer face called
nodes. For the natural probability measure on groves, we compute various
connection probabilities for the nodes in a random grove. In particular, for
"tripartite" pairings of the nodes, the probability can be computed as a
Pfaffian in the entries of the Dirichlet-to-Neumann matrix (discrete Hilbert
transform) of the graph. These formulas generalize the determinant formulas
given by Curtis, Ingerman, and Morrow, and by Fomin, for parallel pairings.
These Pfaffian formulas are used to give exact expressions for reconstruction:
reconstructing the conductances of a planar graph from boundary measurements.
We prove similar theorems for the double-dimer model on bipartite planar
graphs.


title:
Effects of Co substitution on thermodynamic and transport properties and
  anisotropic $H_{c2}$ in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals

abstract:
  Single crystalline samples of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ with $x < 0.12$
have been grown and characterized via microscopic, thermodynamic and transport
measurements. With increasing Co substitution, the thermodynamic and transport
signatures of the structural (high temperature tetragonal to low temperature
orthorhombic) and magnetic (high temperature non magnetic to low temperature
antiferromagnetic) transitions are suppressed at a rate of roughly 15 K per
percent Co. In addition, for $x \ge 0.038$ superconductivity is stabilized,
rising to a maximum $T_c$ of approximately 23 K for $x \approx 0.07$ and
decreasing for higher $x$ values. The $T - x$ phase diagram for
Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ indicates that either superconductivity can
exist in both low temperature crystallographic phases or that there is a
structural phase separation. Anisotropic, superconducting, upper critical field
data ($H_{c2}(T)$) show a significant and clear change in anisotropy between
samples that have higher temperature structural phase transitions and those
that do not. These data show that the superconductivity is sensitive to the
suppression of the higher temperature phase transition.


title:
Thermodynamics of nanodomain formation and breakdown in Scanning Probe
  Microscopy: Landau-Ginzburg-Devonshire approach

abstract:
  Thermodynamics of tip-induced nanodomain formation in scanning probe
microscopy of ferroelectric films and crystals is studied using the
Landau-Ginzburg-Devonshire phenomenological approach. The local redistribution
of polarization induced by the biased probe apex is analyzed including the
effects of polarization gradients, field dependence of dielectric properties,
intrinsic domain wall width, and film thickness. The polarization distribution
inside subcritical nucleus of the domain preceding the nucleation event is very
smooth and localized below the probe, and the electrostatic field distribution
is dominated by the tip. In contrast, polarization distribution inside the
stable domain is rectangular-like, and the associated electrostatic fields
clearly illustrate the presence of tip-induced and depolarization field
components. The calculated coercive biases of domain formation are in a good
agreement with available experimental results for typical ferroelectric
materials. The microscopic origin of the observed domain tip elongation in the
region where the probe electric field is much smaller than the intrinsic
coercive field is the positive depolarization field in front of the moving
counter domain wall. For infinitely thin domain walls local domain breakdown
through the sample depth appears. The results obtained here are complementary
to the Landauer-Molotskii energetic approach.


title: Fractional Quantum Mechanics

abstract:
  A path integral approach to quantum physics has been developed. Fractional
path integrals over the paths of the L\'evy flights are defined. It is shown
that if the fractality of the Brownian trajectories leads to standard quantum
and statistical mechanics, then the fractality of the L\'evy paths leads to
fractional quantum mechanics and fractional statistical mechanics. The
fractional quantum and statistical mechanics have been developed via our
fractional path integral approach. A fractional generalization of the
Schr\"odinger equation has been found. A relationship between the energy and
the momentum of the nonrelativistic quantum-mechanical particle has been
established. The equation for the fractional plane wave function has been
obtained. We have derived a free particle quantum-mechanical kernel using Fox's
H function. A fractional generalization of the Heisenberg uncertainty relation
has been established. Fractional statistical mechanics has been developed via
the path integral approach. A fractional generalization of the motion equation
for the density matrix has been found. The density matrix of a free particle
has been expressed in terms of the Fox's H function. We also discuss the
relationships between fractional and the well-known Feynman path integral
approaches to quantum and statistical mechanics.


title:
A Class of Transformations that Polarize Symmetric Binary-Input
  Memoryless Channels

abstract:
  A generalization of Ar\i kan's polar code construction using transformations
of the form $G^{\otimes n}$ where $G$ is an $\ell \times \ell$ matrix is
considered. Necessary and sufficient conditions are given for these
transformations to ensure channel polarization. It is shown that a large class
of such transformations polarize symmetric binary-input memoryless channels.


title: On locally extremal functions on connected spaces

abstract:
  We construct an example of a real-valued continuous non-constant function $f$
defined on a connected complete metric space $X$ such that every point of $X$
is a point of local minimum or local maximum for $f$. The space $X$ is
connected but fails to be separably connected.


title: Magnetic layers and neutral points near rotating black hole

abstract:
  Magnetic layers are narrow regions where the field direction changes sharply.
They often occur in the association with neutral points of the magnetic field.
We show that an organised field can produce these structures near a rotating
black hole, and we identify them as potential sites of magnetic reconnection.
To that end we study the field lines affected by the frame-dragging effect,
twisting the magnetic structure and changing the position of neutral points. We
consider oblique fields in vacuum. We also include the possibility of
translational motion of the black hole which may be relevant when the black
hole is ejected from the system. The model settings apply to the innermost
regions around black holes with the ergosphere dominated by a
super-equipartition magnetic field and loaded with a negligible gas content.


title:
The Evolution of the Stellar Mass Function of Galaxies from z=4.0 and
  the First Comprehensive Analysis of its Uncertainties: Evidence for
  Mass-dependent Evolution

abstract:
  [Abridged] We present the evolution of the stellar mass function (SMF) of
galaxies from z=4.0 to z=1.3 measured from a sample constructed from the deep
NIR MUSYC, the FIRES, and the GOODS-CDFS surveys, all having very high-quality
optical to mid-infrared data. This sample, unique in that it combines data from
surveys with a large range of depths and areas in a self-consistent way,
allowed us to 1) minimize the uncertainty due to cosmic variance and
empirically quantify its contribution to the total error budget; 2)
simultaneously probe the high-mass end and the low-mass end (down to ~0.05
times the characteristic stellar mass) of the SMF with good statistics; and 3)
empirically derive the redshift-dependent completeness limits in stellar mass.
We provide, for the first time, a comprehensive analysis of random and
systematic uncertainties affecting the derived SMFs. We find that the mass
density evolves by a factor of ~17(+7,-10) since z=4.0, mostly driven by a
change in the normalization Phi*. If only random errors are taken into account,
we find evidence for mass-dependent evolution, with the low-mass end evolving
more rapidly than the high-mass end. However, we show that this result is no
longer robust when systematic uncertainties due to the SED-modeling assumptions
are taken into account. Taking our results at face value, we find that they are
in conflict with semi-analytic models of galaxy formation. The models predict
SMFs that are in general too steep, with too many low-mass galaxies and too few
high-mass galaxies. The discrepancy at the high-mass end is susceptible to
uncertainties in the models and the data, but the discrepancy at the low-mass
end may be more difficult to explain.


title: Metal-Absorption Column Densities in Fast Radiative Shocks

abstract:
  In this paper we present computations of the integrated metal-ion column
densities produced in the post-shock cooling layers behind fast, radiative
shock-waves. For this purpose, we have constructed a new shock code that
calculates the non-equilibrium ionization and cooling; follows the radiative
transfer of the shock self-radiation through the post-shock cooling layers;
takes into account the resulting photoionization and heating rates; follows the
dynamics of the cooling gas; and self-consistently computes the initial
photoionization state of the precursor gas. We discuss the shock structure and
emitted radiation, and study the dependence on the shock velocity, magnetic
field, and gas metallicity. We present a complete set of integrated post-shock
and precursor metal-ion column densities of all ionization stages of the
elements H, He, C, N, O, Ne, Mg, Si, S, and Fe, for shocks with velocities of
600 and ~2000 km/s, corresponding to initial post-shock temperatures of 5e6 and
5e7 K, cooling down to 1000 K. We consider shocks in which the magnetic field
is negligible (B=0) so that the cooling occurs at approximately constant
pressure ("isobaric"), and shocks in which the magnetic pressure dominates
everywhere such that the cooling occurs at constant density (isochoric). We
present results for gas metallicities Z ranging from 1e-3 to twice the solar
abundance of heavy elements, and we study how the observational signatures of
fast radiative shocks depend on Z. We present our numerical results in
convenient online figures and tables, available at
http://wise-obs.tau.ac.il/~orlyg/shocks/


title:
Theory of Andreev reflection in junctions with iron-based High-$T_c$
  superconductors

abstract:
  We construct a theory for low-energy quantum transport in
normal$\mid$superconductor junctions involving the recently discovered
iron-based high-$T_c$ superconductors. We properly take into account both
Andreev bound surface states and the complex Fermi surface topology in our
approach, and investigate the signatures of the possible order parameter
symmetries for the FeAs-lattice. Our results could be helpful in determining
the symmetry of the superconducting state in the iron-pnicitide
superconductors.


title: An 80-kpc Lyman-alpha halo around a high redshift type-2 QSO

abstract:
  We announce the discovery of an extended emission line region associated with
a high redshift type-2 QSO. The halo, which was discovered in our new
wide-field narrow-band survey, resides at z = 2.85 in the Spitzer First Look
Survey region and is extended over ~80 kpc. Deep VLBI observations imply that
approximately 50 per cent of the radio emission is extended on scales > 200pc.
The inferred AGN luminosity is sufficient to ionize the extended halo, and the
optical emission is consistent with being triggered coevally with the radio
source. The Lyman-alpha halo is as luminous as those found around high redshift
radio galaxies, however the active nucleus is several orders of magnitude less
luminous at radio wavelengths than those FRIIs more commonly associated with
extended emission line regions. AMS05 appears to be a high-redshift analogue to
the radio-quiet quasar E1821+643 which is core dominated but which also
exhibits extended FRI-like structure and contains an optically powerful AGN. We
also find evidence for more quiescent kinematics in the Lyman-alpha emission
line in the outer regions of the halo, reminiscent of the haloes around the
more powerful FRIIs. The optical to mid-infrared SED is well described by a
combination of an obscured QSO (L_bol ~3.4 +/- 0.2 x 10^13 Lsolar) and a 1.4
Gyr old simple stellar population with mass ~3.9 +/- 0.3 x 10^11 Msolar.


title: The Galactic Stellar Disc

abstract:
  The study of the Milky Way stellar discs in the context of galaxy formation
is discussed. In particular we explore the properties of the Milky Way disc
using a new sample of about 550 dwarf stars for which we have recently obtained
elemental abundances and ages based on high resolution spectroscopy. For all
the stars we also have full kinematic information as well as information about
their stellar orbits. We confirm results from previous studies that the thin
and the thick disc have distinct abundance patterns. But we also explore a
larger range of orbital parameters than what has been possible in our previous
studies. Several new results are presented. We find that stars that reaches
high above the galactic plane and have eccentric orbits show remarkably tight
abundance trends. This implies that these stars formed out of well mixed gas
that had been homogenized over large volumes. We find some evidence that point
to that the event that most likely caused the heating of this stellar
population happened a few billion years ago. Through a simple, kinematic
exploration of stars with super-solar [Fe/H] we show that the solar
neighbourhood contains metal-rich, high velocity stars that very likely are
associated with the thick disc. Additionally, the HR1614 moving group and the
Hercules and Arcturus stellar streams are discussed and it is concluded that,
probably, a large fraction of the so far identified groups and streams in the
disc are the result of evolution and interactions within the stellar disc
rather than being dissolved stellar clusters or engulfed dwarf galaxies.


title:
Tracers of Chromospheric Structure I: Observations of Ca II K and H
  alpha in M Dwarfs

abstract:
  We report on our observing program to capture simultaneous spectra of Ca II
and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate
the chromospheric temperature structure required to produce these lines at the
observed levels. We find a strong positive correlation between instantaneous
measurements of Ca II K and the Balmer lines in active stars, although these
lines may not be positively correlated in time-resolved measurements. The
relationship between H alpha and Ca II K remains ambiguous for weak and
intermediate activity stars, with H alpha absorption corresponding to a range
of Ca II K emission. A similar relationship is also observed between Ca II K
and the higher order Balmer lines. As our sample consists of a single spectral
type, correlations between these important chromospheric tracers cannot be
ascribed to continuum effects, as suggested by other authors. These data
confirm prior non-simultaneous observations of the H alpha line behavior with
increasing activity, showing an initial increase in the H alpha absorption with
increasing Ca II K emission, prior to H alpha filling in and eventually
becoming a pure emission line in the most active stars. We also compare our
optical measurements with archival UV and X-ray measurements, finding a
positive correlation between the chromospheric and coronal emission for both
high and intermediate activity stars. We compare our results with previous
determinations of the active fraction of low mass stars, and discuss them in
the context of surface inhomogeneity. Lastly, we discuss the application of
these data as empirical constraints on new static models of quiescent M dwarf
atmospheres.


title:
Moments of Nucleon's Parton Distribution for the Sea and Valence Quarks
  from Lattice QCD

abstract:
  We extend the study of lowest moments, $<x>$ and $<x^2>$, of the parton
distribution function of the nucleon to include those of the sea quarks; this
entails a disconnected insertion calculation in lattice QCD. This is carried
out on a $16^3 \times 24$ quenched lattice with Wilson fermion. The quark loops
are calculated with $Z_2$ noise vectors and unbiased subtractions, and multiple
nucleon sources are employed to reduce the statistical errors. We obtain
5$\sigma$ signals for $<x>$ for the $u,d,$ and $s$ quarks, but $<x^2>$ is
consistent with zero within errors. We provide results for both the connected
and disconnected insertions. The perturbatively renormalized $<x>$ for the
strange quark at $\mu = 2$ GeV is $<x>_{s+\bar{s}} = 0.027 \pm 0.006$ which is
consistent with the experimental result. The ratio of $<x>$ for $s$ vs. $u/d$
in the disconnected insertion with quark loops is calculated to be $0.88 \pm
0.07$. This is about twice as large as the phenomenologically fitted
$\displaystyle\frac{< x>_{s+\bar{s}}}{< x>_{\bar{u}}+< x>_{\bar{d}}}$ from
experiments where $\bar{u}$ and $\bar{d}$ include both the connected and
disconnected insertion parts. We discuss the source and implication of this
difference.


title:
Reduction and possible elimination of coating thermal noise using a
  rigidly controlled cavity with a QND technique

abstract:
  Thermal noise of a mirror is one of the most important issues in high
precision measurements such as gravitational-wave detection or cold damping
experiments. It has been pointed out that thermal noise of a mirror with
multi-layer coatings can be reduced by mechanical separation of the layers. In
this paper, we introduce a way to further reduce thermal noise by locking the
mechanically separated mirrors. The reduction is limited by the standard
quantum limit of control noise, but it can be overcome with a
quantum-non-demolition technique, which finally raises a possibility of
complete elimination of coating thermal noise.


title: Decomposition of geometric perturbations

abstract:
  For an infinitesimal deformation of a Riemannian manifold, we prove that the
scalar, vector, and tensor modes in decompositions of perturbations of the
metric tensor, the scalar curvature, the Ricci tensor, and the Einstein tensor
decouple if and only if the manifold is Einstein. Four-dimensional space-time
satisfying the condition of the theorem is homogeneous and isotropic.
Cosmological applications are discussed.


title:
Detection and Cloaking of Molecular Objects in Coherent Nanostructures
  Using Inelastic Electron Tunneling Spectroscopy

abstract:
  We address quantum invisibility in the context of electronics in nanoscale
quantum structures. We make use of the freedom of design that quantum corrals
provide and show that quantum mechanical objects can be hidden inside the
corral, with respect to inelastic electron scattering spectroscopy in
combination with scanning tunneling microscopy, and we propose a design
strategy. A simple illustration of the invisibility is given in terms of an
elliptic quantum corral containing a molecule, with a local vibrational mode,
at one of the foci. Our work has implications to quantum information technology
and presents new tools for nonlocal quantum detection and distinguishing
between different molecules.


title:
Collective single mode precession of electron spins in a quantum dot
  ensemble

abstract:
  We show that the spins of all electrons, each confined in a quantum dot of an
(In,Ga)As/GaAs dot ensemble, can be driven into a single mode of precession
about a magnetic field. This regime is achieved by allowing only a single mode
within the electron spin precession spectrum of the ensemble to be synchronized
with a train of periodic optical excitation pulses. Under this condition a
nuclei induced frequency focusing leads to a shift of all spin precession
frequencies into the synchronized mode. The macroscopic magnetic moment of the
electron spins that is created in this regime precesses without dephasing.


title: On normal stability for nonlinear parabolic equations

abstract:
  We show convergence of solutions to equilibria for quasilinear and fully
nonlinear parabolic evolution equations in situations where the set of
equilibria is non-discrete, but forms a finite-dimensional $C^1$-manifold which
is normally stable.


title: On polygonal relative equilibria in the N-vortex problem

abstract:
  Helmholtz's equations provide the motion of a system of N vortices which
describes a planar incompressible fluid with zero viscosity. A relative
equilibrium is a particular solution of these equations for which the distances
between the vortices are invariant during the motion. In this article, we are
interested in relative equilibria formed of concentric regular polygons of
vortices. We show that in the case of one regular polygon (and a possible
vortex at the center) with more than three vertices (two if there is a vortex
at the center), a relative equilibrium requires equal vorticities (on the
polygon). We also determine all the relative equilibria with two concentric
regular n-gons and the same vorticity on each n-gon. This result completes the
classical studies for two regular n-gons when all the vortices have the same
vorticity or when the total vorticity vanishes.


title:
Development of cryogenic phonon detectors based on CaMoO4 and ZnWO4
  scintillating crystals for direct dark matter search experiments

abstract:
  This work reports on the development of the first phonon detectors based on
CaMoO4 and ZnWO4 scintillating crystals for the CRESST-II experiment. In
particular, a novel technique for the production of the ZnWO4 phonon detector
with a separate thermometer carrier was investigated. The influence of the
thermal and mechanical treatment on the scintillation light output of CaMoO4
and ZnWO4 crystals at room temperature is discussed.


title:
High order perturbative corrections to the determination of |Vub| from
  the P+ spectrum in B -> Xu l nu

abstract:
  We investigate the behaviour of the perturbative relation between the photon
energy spectrum in B -> Xs gamma and the hadronic P+ spectrum in semileptonic B
-> Xu l nu decay at high orders in perturbation theory in the "large-beta_0"
limit, in which only terms of order alpha_s^n beta_0^(n-1) are retained. The
leading renormalon in the weight function W(Delta,P_gamma) relating the two
spectra is confirmed to be at u=1/2, corresponding to nonperturbative
corrections at O(Lambda_QCD/m_b). We show that the P_gamma dependent pieces of
the weight function have no infrared renormalons in this limit, and so the
factorial growth in perturbation theory arises solely from the constant terms.
We find no numerical enhancement of leading logarithms, suggesting that
fixed-order perturbation theory is more appropriate than a leading-log
resummation for the extraction of |Vub|. The importance of various terms in the
expansion of the weight function is studied using a model for the B -> Xs gamma
photon spectrum. Our analysis suggests that higher order perturbative
corrections do not introduce a significant uncertainty in the extraction of
|Vub|.


title:
Extracting Information from the Gravitational Redshift of Compact
  Rotating Objects

abstract:
  When rotation is not taken into account, the measurement of the Gravitational
Redshift can provide unique information about the compactness ($M/R$) of the
star. Rotation alters the gravitational redshift rendering thereby a unique
determination of the compactness parameter impossible. Nevertheless, it can be
shown that by using some theoretical input, useful information on, say, the
radii of compact rotating objects can still be extracted. Moreover, by
measuring the gravitational redshift one can infer the maximum angular velocity
of the object. As it is well known, the minimum observed periods of rotation
are found in millisecond pulsars. Here we show that millisecond periods are
actually a semi-theoretical limit that can be found by General Relativistic
arguments corresponding to the maximum angular velocity. We apply our method to
compact objects such as pulsars, white dwarfs and neutron stars.


title:
Periodic elements of the free idempotent generated semigroup on a
  biordered set

abstract:
  We show that every periodic element of the free idempotent generated
semigroup on an arbitrary biordered set belongs to a subgroup of the semigroup.


title: Robust Regression and Lasso

abstract:
  Lasso, or $\ell^1$ regularized least squares, has been explored extensively
for its remarkable sparsity properties. It is shown in this paper that the
solution to Lasso, in addition to its sparsity, has robustness properties: it
is the solution to a robust optimization problem. This has two important
consequences. First, robustness provides a connection of the regularizer to a
physical property, namely, protection from noise. This allows a principled
selection of the regularizer, and in particular, generalizations of Lasso that
also yield convex optimization problems are obtained by considering different
uncertainty sets.
  Secondly, robustness can itself be used as an avenue to exploring different
properties of the solution. In particular, it is shown that robustness of the
solution explains why the solution is sparse. The analysis as well as the
specific results obtained differ from standard sparsity results, providing
different geometric intuition. Furthermore, it is shown that the robust
optimization formulation is related to kernel density estimation, and based on
this approach, a proof that Lasso is consistent is given using robustness
directly. Finally, a theorem saying that sparsity and algorithmic stability
contradict each other, and hence Lasso is not stable, is presented.


title:
Neutron reactions in accreting neutron stars: a new pathway to efficient
  crust heating

abstract:
  In our calculation of neutron star crust heating we include several key new
model features. In earlier work electron capture (EC) only allowed neutron
emission from the daughter ground-state; here we calculate, in a deformed QRPA
model, EC decay rates to all states in the daughter that are allowed by
Gamow-Teller selection rules and energetics. The subsequent branching ratios
between the 1n,...,xn channels and the competing $\gamma$-decay are calculated
in a Hauser-Feshbach model. Since EC accesses excited states, many more
neutrons are emitted in our calculation than in previous work, leading to
accelerated reaction flows. In our multi-component plasma model a single
(EC,xn) reaction step can produce several neutron-deficient nuclei, each of
which can further decay by (EC,xn). Hence, the neutron emission occurs more
continuously with increasing depth as compared to that in a one-component
plasma model.


title:
Use of a Quantum Computer to do Importance and Metropolis-Hastings
  Sampling of a Classical Bayesian Network

abstract:
  Importance sampling and Metropolis-Hastings sampling (of which Gibbs sampling
is a special case) are two methods commonly used to sample multi-variate
probability distributions (that is, Bayesian networks). Heretofore, the
sampling of Bayesian networks has been done on a conventional "classical
computer". In this paper, we propose methods for doing importance sampling and
Metropolis-Hastings sampling of a classical Bayesian network on a quantum
computer.


title: The large sieve and random walks on left cosets of arithmetic groups

abstract:
  Applying E. Kowalski's recent generalization of the large sieve we prove that
certain properties expected to be typical (irreducibility of the characteristic
polynomial, absence of squares among the matrix coefficients...) are indeed
verified by most (in a very explicit sense) of the elements of GL(n,A) with
fixed determinant (where A is an intermediate ring between Z and Q that we
specify) or by (special) orthogonal matrices with integral entries and fixed
spinor norm.


title:
Universality of second order transport coefficients from the
  gauge-string duality

abstract:
  We consider the strongly coupled limit of conformal gauge theory plasmas with
conserved U(1) charges which have a gravity dual. We show that, under mild
restrictions, the second order transport coefficients of such theories satisfy
a universal relation among themselves, similar to the shear viscosity to
entropy ratio.


title: Solid State Implementation of Quantum Random Walks on General Graphs

abstract:
  Advances in recent years have made it possible to explore quantum dots as a
viable technology for scalable quantum information processing. Charge qubits
for example can be realized in the lowest bound states of coupled quantum dots
and the precision control of the confinement potential allows for the
realization of a full set of universal qubit gates, including arbitrary
single-qubit rotations and two-qubit C-NOT gates. In this work we describe a
novel scheme for implementing quantum random walks on arbitrarily complex
graphs by extending these elementary operations to the control of a
two-dimensional quantum dot grid. As single-qubit rotations constitute the
essential building blocks of our implementation scheme, we also present
numerical simulations of one such mechanism by directly solving the
corresponding time-dependent Schrodinger equation.


title: A Lax Formalism for the Elliptic Difference Painlev\'e Equation

abstract:
  A Lax formalism for the elliptic Painlev\'e equation is presented. The
construction is based on the geometry of the curves on ${\mathbb
P}^1\times{\mathbb P}^1$ and described in terms of the point configurations.


title:
Measurement of sound speed versus depth in Antarctic ice with the South
  Pole Acoustic Test Setup

abstract:
  The feasibility and design of an acoustic neutrino detection array in the
South Pole ice depend on the acoustic properties of the ice. The South Pole
Acoustic Test Setup (SPATS) was built to evaluate the acoustic characteristics
of the ice in the 1 to 100kHz frequency range. The vertical sound speed profile
relates to the level of refraction of the surface noise and determines the
reconstruction precision of the neutrino direction. The SPATS speed of sound
analysis for pressure and shear waves is presented.


title: Signals of Inert Doublet Dark Matter in Neutrino Telescopes

abstract:
  One of the simplest extensions of the Standard Model that explains the
observed abundance of dark matter is the inert doublet model. In this theory a
discrete symmetry ensures that the neutral component of an additional
electroweak doublet scalar is stable, and constitutes a dark matter candidate.
As massive bodies such as the Sun and Earth move through the dark matter halo,
dark matter particles can become gravitationally trapped in their cores.
Annihilations of these particles result in neutrinos, which can potentially be
observed with neutrino telescopes. We calculate the neutrino detection rate at
these experiments from inert doublet dark matter annihilations in the cores of
the Sun and the Earth.


title:
Covariant Effective Action for Loop Quantum Cosmology from Order
  Reduction

abstract:
  Loop quantum cosmology (LQC) seems to be predicting modified effective
Friedmann equations without extra degrees of freedom. A puzzle arises if one
decides to seek for a covariant effective action which would lead to the given
Friedmann equation: The Einstein--Hilbert action is the only action that leads
to second order field equations and, hence, there exists no covariant action
which, under metric variation, leads to modified Friedmann equation without
extra degrees of freedom. It is shown that, at least for isotropic models in
LQC, this issue is naturally resolved and a covariant effective action can be
found if one considers higher order theories of gravity but faithfully follows
effective field theory techniques. However, our analysis also raises doubts on
whether a covariant description without background structures can be found for
anisotropic models.


title: Gravitational Lensing in the metric theory proposed by Sobouti

abstract:
  Recently, Y. Sobouti (2007) has provided a metric theory f(R) that can
account for certain dynamical anomalies observed in spiral galaxies. Mendoza &
Rosas-Guevara (2007) have shown that in this theory there is an extra-bending
as compared to standard general relativity. In the present work we have
developed in more specific detail this additional lensing effect and we have
made evaluations of the alpha parameter used in the model adjusting the theory
to observations in X-rays of 13 clusters of galaxies with gravitational lensing
(Hoekstra (2007)).


title: Relating computational complexity and quantum spectral complexity

abstract:
  It is found that the statistical level fluctuations of the AQC 3-SAT problem
undergo a transition from a poisson (regular) fluctuation form to a form
consistent with the predictions of Random Matrix Theory. We present data which
suggests this transition correlates with the computational phase transition in
the classical 3-SAT problem. Application to Gaussian Processes and implication
for experiment is discussed.


title:
Comment on "Conjectures on exact solution of three-dimensional (3D)
  simple orthorhombic Ising lattices" [arXiv:0705.1045]

abstract:
  It is shown that a recent article by Z.-D. Zhang [arXiv:0705.1045] is in
error and violates well-known theorems.


title:
Bootstrapped Morawetz Estimates And Resonant Decomposition For Low
  Regularity Global Solutions Of Cubic NLS On R^{2}

abstract:
  We prove global well-posedness for the L^{2}-critical cubic defocusing
nonlinear Schr\"odinger equation on R^{2} with data u_{0} \in H^{s}(R^{2}) for
s > {1/3}.


title:
The radius and other fundamental parameters of the F9 V star beta
  Virginis

abstract:
  We have used the Sydney University Stellar Interferometer (SUSI) to measure
the angular diameter of the F9 V star beta Virginis. After correcting for limb
darkening and combining with the revised Hipparcos parallax, we derive a radius
of 1.703 +/- 0.022 R_sun (1.3%). We have also calculated the bolometric flux
from published measurements which, combined with the angular diameter, implies
an effective temperature of 6059 +/- 49 K (0.8%). We also derived the
luminosity of beta Vir to be L = 3.51 +/- 0.08 L_sun (2.1%). Solar-like
oscillations were measured in this star by Carrier et al. (2005) and using
their value for the large frequency separation yields the mean stellar density
with an uncertainty of about 2%. Our constraints on the fundamental parameters
of beta Vir will be important to test theoretical models of this star and its
oscillations.


title: On a Nonlinear Newtonian Gravity and Charging a Black Hole

abstract:
  A scalar field gravitational analog of the Reissner-Nordstrom solution is
investigated. The nonlinear Newtonian model has an upper-limit of charge for a
central mass which agrees with the general relativistic condition required for
the existence of the black hole horizon. The maximum limit for accumulation by
bombardment of charged particles is found. The aim is to investigate the
resulting physics after severing the effects of curvature from the effects of
energy-mass equivalence.


title: Mass Matrices and Their Renormalization

abstract:
  We obtain explicitly the renormalization group equations for the quark mass
matrices in terms of a set of rephasing invariant parameters. For a range of
assumed high energy values for the mass ratios and mixing parameters, they are
found to evolve rapidly and develop hierarchies as the energy scale decreases.
To achieve the experimentally observed high degree of hierarchy, however, the
introduction of new models with specific properties becomes necessary.


title:
Nonlinear Stresses and Temperatures in Transient Adiabatic and Shear
  Flows via Nonequilibrium Molecular Dynamics -- Three Definitions of
  Temperature

abstract:
  We compare nonlinear stresses and temperatures for adiabatic shear flows,
using up to 262,144 particles, with those from corresponding homogeneous and
inhomogeneous flows. Two varieties of kinetic temperature tensors are compared
to the configurational temperatures. This comparison leads to an improved form
for the local and instantaneous smooth-particle averaged stream velocity and to
a recognition of rotational contributions to the configurational temperature.


title:
Self-Organizing Maps. An application to the OGLE data and the Gaia
  Science Alerts

abstract:
  Self-Organizing Map (SOM) is a promising tool for exploring large
multi-dimensional data sets. It is quick and convenient to train in an
unsupervised fashion and, as an outcome, it produces natural clusters of data
patterns. An example of application of SOM to the new OGLE-III data set is
presented along with some preliminary results.
  Once tested on OGLE data, the SOM technique will also be implemented within
the Gaia mission's photometry and spectrometry analysis, in particular, in
so-called classification-based Science Alerts. SOM will be used as a basis of
this system as the changes in brightness and spectral behaviour of a star can
be easily and quickly traced on a map trained in advance with simulated and/or
real data from other surveys.


title:
Measures and dimensions of Julia sets of semi-hyperbolic rational
  semigroups

abstract:
  We consider the dynamics of semi-hyperbolic semigroups generated by finitely
many rational maps on the Riemann sphere. Assuming that the nice open set
condition holds it is proved that there exists a geometric measure on the Julia
set with exponent $h$ equal to the Hausdorff dimension of the Julia set. Both
$h$-dimensional Hausdorff and packing measures are finite and positive on the
Julia set and are mutually equivalent with Radon-Nikodym derivatives uniformly
separated from zero and infinity. All three fractal dimensions, Hausdorff,
packing and box counting are equal. It is also proved that for the canonically
associated skew-product map there exists a unique $h$-conformal measure.
Furthermore, it is shown that this conformal measure admits a unique Borel
probability absolutely continuous invariant (under the skew-product map)
measure. In fact these two measures are equivalent, and the invariant measure
is metrically exact, hence ergodic.


title: Sur la lin\'earisation des tissus

abstract:
  We give a simple analytic criterion which characterizes linearizable
1-codimensional webs. Then we give an invariant geometrical interpretation of
it, in term of projective connection. We explain then how our approach allows
to study linearization of more general objects than 1-codimensional webs. By
way of illustration, we treat some explicit interesting examples.


title:
Current-voltage characteristics of NdFeAsO0.85F0.15 and NdFeAsO0.85
  superconductors

abstract:
  The vortex phase diagrams of NdFeAsO0.85F0.15 and NdFeAsO0.85 superconductors
are determined from the analysis of resistivity and current-voltage (I-V)
measurements in magnetic fields up to 9 T. A clear vortex glass to liquid
transition is identified only in the oxygen deficient NdFeAsO0.85, in which I-V
curves can be well scaled onto liquid and glass branches consistent with the
vortex glass theory. With increasing magnetic field, the activation energy U0,
deduced from the Arrhenius plots of resistivity based on the thermally
activated flux-flow model (TAFF), decays more quickly for NdFeAsO0.85F0.15 than
for NdFeAsO0.85. Moreover, the irreversibility field Hirr of NdFeAsO0.85
increases more rapidly than that of NdFeAsO0.85F0.15 with decreasing
temperature. These observations evidence the strong vortex pinning effects,
presumably caused by the enhanced defects and disorders in the oxygen deficient
NdFeAsO0.85. It is inferred that the enhanced defects and disorder can be also
responsible for the vortex glass to liquid transition in the NdFeAsO0.85.


title:
Distribution amplitudes of $\Sigma$ and $\Lambda$ and their
  electromagnetic form factors

abstract:
  Based on QCD conformal partial wave expansion to leading order conformal spin
accuracy, we present the light-cone distribution amplitudes (DAs) of $\Sigma$
and $\Lambda$ baryons up to twist 6. It is concluded that fourteen ndependent
DAs are needed to describe the valence three-quark states of the baryons at
small transverse separations. The nonperturbative parameters relevant to the
DAs are determined within the framework of QCD sum rule method. With the
obtained DAs, a simple investigation on the electromagnetic form factors of
these baryons are given. The magnetic moments of the baryons are estimated by
fitting the magnetic form factor with the dipole formula.


title:
On the evolution of mean motion resonances through stochastic forcing:
  Fast and slow libration modes and the origin of HD128311

abstract:
  Aims. We clarify the response of extrasolar planetary systems in a 2:1 mean
motion commensurability with masses ranging from the super Jovian range to the
terrestrial range to stochastic forcing that could result from protoplanetary
disk turbulence. The behaviour of the different libration modes for a wide
range of system parameters and stochastic forcing magnitudes is investigated.
The growth of libration amplitudes is parameterized as a function of the
relevant physical parameters. The results are applied to provide an explanation
of the configuration of the HD128311 system.
  Methods. We first develop an analytic model from first principles without
making the assumption that both eccentricities are small. We also perform
numerical N-body simulations with additional stochastic forcing terms to
represent the effects of putative disk turbulence.
  Results. Systems are quickly destabilized by large magnitudes of stochastic
forcing but some stability is imparted should systems undergo a net orbital
migration. The slow mode, which mostly corresponds to motion of the angle
between the apsidal lines of the two planets, is converted to circulation more
readily than the fast mode which is associated with oscillations of the
semi-major axes. This mode is also vulnerable to the attainment of small
eccentricities which causes oscillations between periods of libration and
circulation.
  Conclusions. Stochastic forcing due to disk turbulence may have played a role
in shaping the configurations of observed systems in mean motion resonance. It
naturally provides a mechanism for accounting for the HD128311 system.


title: Dynamics of confined suspensions of swimming particles

abstract:
  Low Reynolds number direct simulations of large populations of
hydrodynamically interacting swimming particles confined between planar walls
are performed. The results of simulations are compared with a theory that
describes dilute suspensions of swimmers. The theory yields scalings with
concentration for diffusivities and velocity fluctuations as well as a
prediction of the fluid velocity spatial autocorrelation function. Even for
uncorrelated swimmers, the theory predicts anticorrelations between nearby
fluid elements that correspond to vortex-like swirling motions in the fluid
with length scale set by the size of a swimmer and the slit height. Very
similar results arise from the full simulations indicating either that
correlated motion of the swimmers is not significant at the concentrations
considered or that the fluid phase autocorrelation is not a sensitive measure
of the correlated motion. This result is in stark contrast with results from
unconfined systems, for which the fluid autocorrelation captures large-scale
collective fluid structures. The additional length scale (screening length)
introduced by the confinement seems to prevent these large-scale structures
from forming.


title:
Design of a multichannel 127 degree cylindrical spectrometer for
  sputtered ions

abstract:
  Design details of a 127 degree electrostatic cylindrical spectrometer
equipped with a position-sensitive micro-channel plate detector for measuring
the sputtered ions in collisions of highly charged ions with solid surface is
described. The nonlinear relationship between the point of fall versus the
ionic energy, the blurring of the point of fall caused by the divergence of
incident angle and the finite entrance aperture, the transform from a position
spectrum to an energy spectrum, as well as the influence of the fringing fields
are discussed.


title:
Measuring the frequency of a Sr optical lattice clock using a 120-km
  coherent optical transfer

abstract:
  We demonstrate a precision frequency measurement using a phase-stabilized
120-km optical fiber link over a physical distance of 50 km. The transition
frequency of the 87Sr optical lattice clock at the University of Tokyo is
measured to be 429228004229874.1(2.4) Hz referenced to international atomic
time (TAI). The measured frequency agrees with results obtained in Boulder and
Paris at a 6*10^-16 fractional level, which matches the current best
evaluations of Cs primary frequency standards. The results demonstrate the
excellent functions of the intercity optical fibre link, and the great
potential of optical lattice clocks for use in the redefinition of the second.


title: Proposal for a Photonic Remote Active Heat Sink Technology (PHRAHST)

abstract:
  We propose a new method to effect heat removal from an object by using a
laser beam. The proposed method is based on inelastic scattering of a laser
beam from the object and in particular by making the anti-Stokes emission more
efficient than the Stokes emission. In that manner more energy is removed from
the body per unit time than deposited. Various ways are outlined in order to
achieve this result ranging from careful selection of the laser frequency with
respect to the resonant frequencies of the medium, use of the frequency
dependence of the density of electromagnetic modes in a three-dimensional
system, use of photonic crystals and the polarization dependence of
electromagnetic modes in cavities. The proposed methods could find use for
example in the cooling of devices of nanoscale dimensions.


title:
A non-existence theorem for Morse type holomorphic foliations of
  codimension one transverse to spheres

abstract:
  We prove that a Morse type codimension one holomorphic foliation is not
transverse to a sphere in the complex affine space. Also we characterize the
variety of contacts of a linear foliation with concentric spheres.


title: Geometric aspects of dibaryon operators

abstract:
  The AdS/CFT correspondence for N=1 Super conformal field theories suggests
that dibaryon operators are dual to D-brane states that are point like in AdS
and that wrap various cycles in a Sasaki-Einstein manifold. It also suggests
that the volume of the D-brane gives the R-charge of the corresponding
operator. We elucidate various aspects of this correspondence, paying
particular care to study the case of branes at the tip of three different
Calabi Yau cones. We show that the arrows in the quiver diagram describing the
conformal field theory can be thought of as global sections of a non-trivial
holomorphic vector bundle over the Calabi-Yau geometry. We suggest that the
zero locus of these sections gives the geometric map that lets us tie a
particular dibaryon to a holomorphic cycle, by intersecting the corresponding
cycle with the Sasaki-Einstein locus at fixed distance from the origin. We show
that this can be compared with the corresponding volumes of the Sasaki-Einstein
space and that one gets exact agreement between the volumes of the cycles
identified with this procedure and the R-charges of the operators.


title: Surfaces of bounded mean curvature in Riemannian manifolds

abstract:
  Consider a sequence of closed, orientable surfaces of fixed genus $g$ in a
Riemannian manifold $M$ with uniform upper bounds on mean curvature and area.
We show that on passing to a subsequence and choosing appropriate
parametrisations, the inclusion maps converge in $C^0$ to a map from a surface
of genus $g$ to $M$.
  We also show that, on passing to a further subsequence, the distance
functions corresponding to pullback metrics converge to a pseudo-metric of
fractal dimension two.
  As a corollary, we obtain a purely geometric result. Namely, we show that
bounds on the mean curvature, area and genus of a surface $F\subset M$ together
with bounds on the geometry of $M$ give an upper bound on the diameter of $F$.
  Our proof is modelled on Gromov's compactness theorem for $J$-holomorphic
curves.


title: Berry Phase in a Two-atom Jaynes-Cummings Model with Kerr Medium

abstract:
  he Jaynes-Cummings model (JCM) is an very important model for describing
interaction between quantized electromagnetic fields and atoms in cavity
quantum electrodynamics (QED). This model is generalized in many different
direction since it predicts many novel quantum effects that can be verified by
modern physics experimental technologies. In this paper, the Berry phase and
entropy of the ground state for arbitrary photon number $n$ of a two-atom
Jaynes-Cummings model with Kerr like medium are investigated. It is found that
there are some correspondence between their images, especially the existence of
a curve in the $\Delta-\varepsilon$ plane along which the energy, Berry phase
and entropy all reach their special values. So it is available for detecting
entanglement by applying Berry phase.


title:
CERN-INO magical Beta-beam experiment: A high precision probe for
  neutrino parameters

abstract:
  This talk is an attempt to underscore in detail the physics reach of an
experimental set-up where neutrinos produced in a beta-beam facility at CERN
would be observed in the proposed large magnetized iron calorimeter detector
(ICAL) at the India-based Neutrino Observatory (INO). The "magical" CERN-INO
beta-beam set-up offers an excellent avenue to use the "Golden" channel ($\nu_e
\to \nu_{\mu}$) oscillation probability for a simultaneous determination of the
neutrino mass ordering and $\theta_{13}$ avoiding the impact of the CP phase
$\delta_{CP}$ on these measurements. With Lorentz boost $\gamma=650$ and
irrespective of the true value of $\delta_{CP}$, the neutrino mass hierarchy
could be determined at $3\sigma$ C.L. if $\sin^22\theta_{13}{\rm {(true)}} >
5.6 \times 10^{-4}$ and we can expect an unambiguous signal for $\theta_{13}$
at $3\sigma$ C.L. if $\sin^22\theta_{13}{\rm {(true)}} > 5.1 \times 10^{-4}$
independent of the true neutrino mass hierarchy.


title:
Increasing Average Period Lengths by Switching of Robust Chaos Maps in
  Finite Precision

abstract:
  Grebogi, Ott and Yorke (Phys. Rev. A 38(7), 1988) have investigated the
effect of finite precision on average period length of chaotic maps. They
showed that the average length of periodic orbits ($T$) of a dynamical system
scales as a function of computer precision ($\epsilon$) and the correlation
dimension ($d$) of the chaotic attractor: $T \sim \epsilon^{-d/2}$. In this
work, we are concerned with increasing the average period length which is
desirable for chaotic cryptography applications. Our experiments reveal that
random and chaotic switching of deterministic chaotic dynamical systems yield
higher average length of periodic orbits as compared to simple sequential
switching or absence of switching. To illustrate the application of switching,
a novel generalization of the Logistic map that exhibits Robust Chaos (absence
of attracting periodic orbits) is first introduced. We then propose a
pseudo-random number generator based on chaotic switching between Robust Chaos
maps which is found to successfully pass stringent statistical tests of
randomness.


title:
Noncommutative Gelfand Duality and Applications I: The Existence of
  invariant subspaces

abstract:
  Gelfand duality between unital commutative C*-algebras and Compact Hausdorff
spaces is extended to all unital C*-algebras, where the dual objects are what
we call compact Hausdorff quantum spaces. We apply this result to obtain, a
characterization of unitary groups of C*-algebras, and, for arbitrary bounded
Hilbert space operators, (i) A spectral theorem cum continuous functional
calculus, and (ii) A proof of the general Invariant Subspace Theorem. Also
described is a nonabelian generalization of Pontryagin duality of abelian
locally compact groups.


title: A Divergence Formula for Randomness and Dimension

abstract:
  If $S$ is an infinite sequence over a finite alphabet $\Sigma$ and $\beta$ is
a probability measure on $\Sigma$, then the {\it dimension} of $ S$ with
respect to $\beta$, written $\dim^\beta(S)$, is a constructive version of
Billingsley dimension that coincides with the (constructive Hausdorff)
dimension $\dim(S)$ when $\beta$ is the uniform probability measure. This paper
shows that $\dim^\beta(S)$ and its dual $\Dim^\beta(S)$, the {\it strong
dimension} of $S$ with respect to $\beta$, can be used in conjunction with
randomness to measure the similarity of two probability measures $\alpha$ and
$\beta$ on $\Sigma$. Specifically, we prove that the {\it divergence formula}
\[
  \dim^\beta(R) = \Dim^\beta(R) =\frac{\CH(\alpha)}{\CH(\alpha) + \D(\alpha ||
\beta)} \] holds whenever $\alpha$ and $\beta$ are computable, positive
probability measures on $\Sigma$ and $R \in \Sigma^\infty$ is random with
respect to $\alpha$. In this formula, $\CH(\alpha)$ is the Shannon entropy of
$\alpha$, and $\D(\alpha||\beta)$ is the Kullback-Leibler divergence between
$\alpha$ and $\beta$. We also show that the above formula holds for all
sequences $R$ that are $\alpha$-normal (in the sense of Borel) when
$\dim^\beta(R)$ and $\Dim^\beta(R)$ are replaced by the more effective
finite-state dimensions $\dimfs^\beta(R)$ and $\Dimfs^\beta(R)$. In the course
of proving this, we also prove finite-state compression characterizations of
$\dimfs^\beta(S)$ and $\Dimfs^\beta(S)$.


title:
Accurate path integration in continuous attractor network models of grid
  cells

abstract:
  Grid cells in the rodent entorhinal cortex display strikingly regular firing
responses to the animal's position in 2-D space, and have been hypothesized to
form the neural substrate for dead-reckoning. However, in previous models
suggested for grid cell activity, errors accumulate rapidly in the integration
of velocity inputs. To produce grid-cell like responses, these models would
require frequent resets triggered by external sensory cues, casting doubt on
the dead-reckoning potential of the grid cell system. Here we focus on the
accuracy of path integration in continuous attractor models of grid cell
activity. We show, in contrast to previous models, that continuous attractor
models can generate regular triangular grid responses, based on inputs that
encode only the rat's velocity and heading. We consider the role of the network
boundary in integration performance, and show that both periodic and aperiodic
networks are capable of accurate path integration, despite important
differences in their attractor manifolds. We show that the rate at which errors
accumulate in the integration of velocity depends on the network's organization
and size, and on the intrinsic noise within the network. With a plausible range
of parameters and the inclusion of spike variability, our model can accurately
integrate velocity inputs over a maximum of ~10-100 m and ~1-10 minutes. These
findings form a proof-of-concept that continuous attractor dynamics may
underlie velocity integration in dMEC. The simulations also generate pertinent
upper bounds on the accuracy of integration that may be achieved by continuous
attractor dynamics in the grid cell network. We suggest experiments to test the
continuous attractor model and differentiate it from models in which single
cells establish their responses independently of each other.


title: Structure of the fermion propagator in QED3

abstract:
  Minkowski structure of the Fermion propagator in QED$_{2+1}$ is evaluated
using dispersion like method Including massive fermion loop to the photon
spectral function there is no infrared divergences in the gauge d=-1.Screening
effects suppress the chiral order parmeter for small numbers of fermion flavour
N.We evaluate the order parameter as a function of coupling constant c and
N.There exsists a critical region where the chiral symmetry is dynamically
broken.


title: Probing neutrino parameters with a Two-Baseline Beta-beam set-up

abstract:
  We discuss the prospects of exploring the neutrino mass parameters with a
CERN based Beta-beam experiment using two different detectors at two different
baselines. The proposed set-up consists of a 50 kton iron calorimeter (ICAL) at
a baseline of around 7150 km which is roughly the magic baseline, e.g.,
ICAL@INO, and a 50 kton Totally Active Scintillator Detector at a distance of
730 km, e.g., at Gran Sasso. We take 8B and 8Li source ions with a boost factor
$\gamma$ of 650 for the magic baseline while for the closer detector we
consider 18Ne and 6He ions with a range of Lorentz boosts. We find that the
locations of the two detectors complement each other leading to an exceptional
high sensitivity. With $\gamma=650$ for 8B/8Li and $\gamma=575$ for 18Ne/6He
and total luminosity corresponding to $5\times (1.1\times 10^{19})$ and
$5\times (2.9\times 10^{19})$ useful ion decays in neutrino and antineutrino
modes respectively, we find that the two-detector set-up can probe maximal CP
violation and establish the neutrino mass ordering if $\sin^22\theta_{13}$ is
$1.8 \times 10^{-5}$ and $4.6 \times 10^{-5}$, respectively, or more. The
sensitivity reach for $\sin^22\theta_{13}$ itself is $5.3 \times 10^{-5}$. CP
violation can be discovered for 64% of the possible $\delta_{CP}$ values for
$\sin^22\theta_{13} \geq 8\times 10^{-5}$.


title:
Fast Adaptive Flat-histogram Ensemble for Calculating Density of States
  and Enhanced Sampling in Large Systems

abstract:
  We presented an efficient algorithm, fast adaptive flat-histogram ensemble
(FAFE), to estimate the density of states (DOS) and to enhance sampling in
large systems. FAFE calculates the means of an arbitrary extensive variable $U$
in generalized ensembles to form points on the curve $\beta_{s}(U) \equiv
\frac{\partial S(U)}{\partial U}$, the derivative of the logarithmic DOS.
Unlike the popular Wang-Landau-like (WLL) methods, FAFE satisfies the
detailed-balance condition through out the simulation and automatically
generates non-uniform $(\beta_{i}, U_{i})$ data points to follow the real
change rate of $\beta_{s}(U)$ in different $U$ regions and in different
systems. Combined with a $U-$compression transformation, FAFE reduces the
required simulation steps from $O(N^{3/2})$ in WLL to $O(N^{1/2})$, where $N$
is the system size. We demonstrate the efficiency of FAFE in Lennard-Jones
liquids with several $N$ values. More importantly, we show its abilities in
finding and identifying different macroscopic states including meta-stable
states in phase co-existing regions.


title:
X-Ray Reflection Nebulae with Large Equivalent Widths of Neutral Iron Ka
  Line in the Sgr C Region

abstract:
  This paper reports on the first results of the Suzaku observation in the Sgr
C region. We detected four diffuse clumps with strong line emission at 6.4keV,
Ka from neutral or low-ionized Fe. One of them, M359.38-0.00, is newly
discovered with Suzaku. The X-ray spectra of the two bright clumps,
M359.43-0.07 and M359.47-0.15, after subtracting the Galactic center diffuse
X-ray emission (GCDX), exhibit strong Ka line from FeI with large equivalent
widths (EWs) of 2.0-2.2keV and clear Kb of FeI. The GCDX in the Sgr C region is
composed of the 6.4keV- and 6.7keV-associated components. These are
phenomenologically decomposed by taking relations between EWs of the 6.4keV and
6.7keV lines. Then the former EWs against the associated continuum in the
bright clump regions are estimated to be 2.4(+2.3_-0.7)keV. Since the two
different approaches give similar large EWs of 2keV, we strongly suggest that
the 6.4keV clumps in the Sgr C region are due to X-ray reflection/fluorescence
(the X-ray reflection nebulae).


title:
An application of principal stratification to control for
  institutionalization at follow-up in studies of substance abuse treatment
  programs

abstract:
  Participants in longitudinal studies on the effects of drug treatment and
criminal justice system interventions are at high risk for institutionalization
(e.g., spending time in an environment where their freedom to use drugs, commit
crimes, or engage in risky behavior may be circumscribed). Methods used for
estimating treatment effects in the presence of institutionalization during
follow-up can be highly sensitive to assumptions that are unlikely to be met in
applications and thus likely to yield misleading inferences. In this paper we
consider the use of principal stratification to control for
institutionalization at follow-up. Principal stratification has been suggested
for similar problems where outcomes are unobservable for samples of study
participants because of dropout, death or other forms of censoring. The method
identifies principal strata within which causal effects are well defined and
potentially estimable. We extend the method of principal stratification to
model institutionalization at follow-up and estimate the effect of residential
substance abuse treatment versus outpatient services in a large scale study of
adolescent substance abuse treatment programs. Additionally, we discuss
practical issues in applying the principal stratification model to data. We
show via simulation studies that the model can only recover true effects
provided the data meet strenuous demands and that there must be caution taken
when implementing principal stratification as a technique to control for
post-treatment confounders such as institutionalization.


title:
The Fermi-Pasta-Ulam paradox, Anderson Localization problem and the
  generalized diffusion approach

abstract:
  The goal of this paper is two-fold. First, based on the interpretation of a
quantum tight-binding model in terms of a classical Hamiltonian map, we
consider the Anderson localization (AL) problem as the Fermi-Pasta-Ulam (FPU)
effect in a modified dynamical system containing both stable and unstable
(inverted) modes. Delocalized states in the AL are analogous to the stable
quasi-periodic motion in FPU; whereas localized states are analogous to
thermalization, respectively. The second aim is to use the classical Hamilton
map for a simplified derivation of \textit{exact} equations for the
localization operator $H(z)$. The letter was presented earlier [J.Phys.:
Condens. Matter {\bf 14} (2002) 13777] treating the AL as a generalized
diffusion in a dynamical system. We demonstrate that counter-intuitive results
of our studies of the AL are similar to the FPU counter-intuitivity.


title: Spherical Collapse in Modified Newtonian Dynamics (MOND)

abstract:
  Modeling the structure formation in the universe, we extend the spherical
collapse model in the context of MOND starting with the linear Newtonian
structure formation followed by the MONDian evolution. In MOND the formation of
structures speed up without a need for dark matter. Starting with the top-hat
over-dense distribution of the matter, the structures virialize with a
power--law profile of the distribution of matter. We show that the
virialization process takes place gradually from the center of the structure to
the outer layers. In this scenario the smaller structures enter to the MONDian
regime earlier and evolve faster, hence they are older than larger structures.
We also show that the virialization of the structures occur in the MONDian
regime, in which the smaller structures have stronger gravitational
acceleration than the larger ones. This feature of the dynamical behavior of
the structures is in agreement with this fact that the smaller structures as
the globular clusters or galactic bulges have been formed earlier and need less
dark matter in CDM scenario.