title:
GossiCrypt: Wireless Sensor Network Data Confidentiality Against
  Parasitic Adversaries

abstract:
  Resource and cost constraints remain a challenge for wireless sensor network
security. In this paper, we propose a new approach to protect confidentiality
against a parasitic adversary, which seeks to exploit sensor networks by
obtaining measurements in an unauthorized way. Our low-complexity solution,
GossiCrypt, leverages on the large scale of sensor networks to protect
confidentiality efficiently and effectively. GossiCrypt protects data by
symmetric key encryption at their source nodes and re-encryption at a randomly
chosen subset of nodes en route to the sink. Furthermore, it employs key
refreshing to mitigate the physical compromise of cryptographic keys. We
validate GossiCrypt analytically and with simulations, showing it protects data
confidentiality with probability almost one. Moreover, compared with a system
that uses public-key data encryption, the energy consumption of GossiCrypt is
one to three orders of magnitude lower.


title: Degree formula for connective K-theory

abstract:
  We apply the degree formula for connective $K$-theory to study rational
contractions of algebraic varieties. Examples include rationally connected
varieties and complete intersections.


title: Universal Malliavin Calculus in Fock and L\'{e}vy-It\^{o} Spaces

abstract:
  We review and extend Lindsay's work on abstract gradient and divergence
operators in Fock space over a general complex Hilbert space. Precise
expressions for the domains are given, the $L^2$-equivalence of norms is proved
and an abstract version of the It\^{o}-Skorohod isometry is established. We
then outline a new proof of It\^{o}'s chaos expansion of complex
L\'{e}vy-It\^{o} space in terms of multiple Wiener-L\'{e}vy integrals based on
Brownian motion and a compensated Poisson random measure. The duality transform
now identifies L\'{e}vy-It\^{o} space as a Fock space. We can then easily
obtain key properties of the gradient and divergence of a general L\'{e}vy
process. In particular we establish maximal domains of these operators and
obtain the It\^{o}-Skorohod isometry on its maximal domain.


title: Faraday waves in elongated superfluid fermionic clouds

abstract:
  We use hydrodynamic equations to study the formation of Faraday waves in a
superfluid Fermi gas at zero temperature confined in a strongly elongated
cigar-shaped trap. First, we treat the role of the radial density profile in
the limit of an infinite cylindrical geometry and analytically evaluate the
wavelength of the Faraday pattern. The effect of the axial confinement is fully
taken into account in the numerical solution of hydrodynamic equations and
shows that the infinite cylinder geometry provides a very good description of
the phenomena.


title: Mirror dark matter discovered?

abstract:
  Recent astrophysical data indicates that dark matter shows a controversial
behaviour in galaxy cluster collisions. In case of the notorious Bullet
cluster, dark matter component of the cluster behaves like a collisionless
system. However, its behaviour in the Abell 520 cluster indicates a significant
self-interaction cross-section. It is hard for the WIMP based dark matter
models to reconcile such a diverse behaviour. Mirror dark matter models, on the
contrary, are more flexible and for them diverse behaviour of the dark matter
is a natural expectation.


title: Parameterized Telescoping Proves Algebraic Independence of Sums

abstract:
  Usually creative telescoping is used to derive recurrences for sums. In this
article we show that the non-existence of a creative telescoping solution, and
more generally, of a parameterized telescoping solution, proves algebraic
independence of certain types of sums. Combining this fact with
summation-theory shows transcendence of whole classes of sums. Moreover, this
result throws new light on the question why, e.g., Zeilberger's algorithm fails
to find a recurrence with minimal order.


title: IMEX evolution of scalar fields on curved backgrounds

abstract:
  Inspiral of binary black holes occurs over a time-scale of many orbits, far
longer than the dynamical time-scale of the individual black holes. Explicit
evolutions of a binary system therefore require excessively many time steps to
capture interesting dynamics. We present a strategy to overcome the
Courant-Friedrichs-Lewy condition in such evolutions, one relying on modern
implicit-explicit ODE solvers and multidomain spectral methods for elliptic
equations. Our analysis considers the model problem of a forced scalar field
propagating on a generic curved background. Nevertheless, we encounter and
address a number of issues pertinent to the binary black hole problem in full
general relativity. Specializing to the Schwarzschild geometry in Kerr-Schild
coordinates, we document the results of several numerical experiments testing
our strategy.


title: MHV, CSW and BCFW: field theory structures in string theory amplitudes

abstract:
  Motivated by recent progress in calculating field theory amplitudes, we study
applications of the basic ideas in these developments to the calculation of
amplitudes in string theory. We consider in particular both non-Abelian and
Abelian open superstring disk amplitudes in a flat space background, focusing
mainly on the four-dimensional case. The basic field theory ideas under
consideration split into three separate categories. In the first, we argue that
the calculation of alpha'-corrections to MHV open string disk amplitudes
reduces to the determination of certain classes of polynomials. This line of
reasoning is then used to determine the alpha'^3-correction to the MHV
amplitude for all multiplicities. A second line of attack concerns the
existence of an analog of CSW rules derived from the Abelian Dirac-Born-Infeld
action in four dimensions. We show explicitly that the CSW-like perturbation
series of this action is surprisingly trivial: only helicity conserving
amplitudes are non-zero. Last but not least, we initiate the study of BCFW
on-shell recursion relations in string theory. These should appear very
naturally as the UV properties of the string theory are excellent. We show that
all open four-point string amplitudes in a flat background at the disk level
obey BCFW recursion relations. Based on the naturalness of the proof and some
explicit results for the five-point gluon amplitude, it is expected that this
pattern persists for all higher point amplitudes and for the closed string.


title:
Inelastic scattering in a monolayer graphene sheet; a weak-localization
  study

abstract:
  Charge carriers in a graphene sheet, a single layer of graphite, exhibit much
distinctive characteristics to those in other two-dimensional electronic
systems because of their chiral nature. In this report, we focus on the
observation of weak localization in a graphene sheet exfoliated from a piece of
natural graphite and nano-patterned into a Hall-bar geometry. Much stronger
chiral-symmetry-breaking elastic intervalley scattering in our graphene sheet
restores the conventional weak localization. The resulting carrier-density and
temperature dependence of the phase coherence length reveal that the
electron-electron interaction including a direct Coulomb interaction is the
main inelastic scattering factor while electron-hole puddles enhance the
inelastic scattering near the Dirac point.


title: Quantum transport through STM-lifted single PTCDA molecules

abstract:
  Using a scanning tunneling microscope we have measured the quantum
conductance through a PTCDA molecule for different configurations of the
tip-molecule-surface junction. A peculiar conductance resonance arises at the
Fermi level for certain tip to surface distances. We have relaxed the molecular
junction coordinates and calculated transport by means of the Landauer/Keldysh
approach. The zero bias transmission calculated for fixed tip positions in
lateral dimensions but different tip substrate distances show a clear shift and
sharpening of the molecular chemisorption level on increasing the STM-surface
distance, in agreement with experiment.


title: Geodesic Structure of the Schwarzschild Black Hole in Rainbow Gravity

abstract:
  In this paper we study the geodesic structure of the Schwarzschild black hole
in rainbow gravity analyzing the behavior of null and time-like geodesic. We
find that the structure of the geodesics essentially does not change when the
semi-classical effects are included. However, we can distinguish different
scenarios if we take into account the effects of rainbow gravity. Depending on
the type of rainbow functions under consideration, inertial and external
observers see very different situations in radial and non radial motion of a
test particles.


title: Easily testable logical networks based on a 'widened long flip-flop'

abstract:
  The article describes an attempt to solve at once three basic problems
arising at testing a complex digital equipment for defects: 1) the problem of
an exponential increasing of the complexity of testing the equipment with the
complexity of the equipment; 2) the problem of testing of the tester; 3) the
problem of a mutual masking of defects. The proposed solution is nothing more
than using certain limitations for connections between usual logical gates.
Arbitrary multiple stuck-at-faults are supposed as defects.


title:
Are Optically-Selected Quasars Universally X-Ray Luminous? X-Ray/UV
  Relations in Sloan Digital Sky Survey Quasars

abstract:
  We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan
Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7 <= z <=
2.7 in order to characterize the relative UV and X-ray spectral properties of
QSOs that do not have broad UV absorption lines (BALs). We constrain the
fraction of X-ray weak, non-BAL QSOs and find that such objects are rare; for
example, sources underluminous by a factor of 10 comprise $\la$2% of
optically-selected SDSS QSOs. X-ray luminosities vary with respect to UV
emission by a factor of $\la$2 over several years for most sources. UV
continuum reddening and the presence of narrow-line absorbing systems are not
strongly associated with X-ray weakness in our sample. X-ray brightness is
significantly correlated with UV emission line properties, so that relatively
X-ray weak, non-BAL QSOs generally have weaker, blueshifted CIV$\lambda$1549
emission and broader CIII]$\lambda$1909 lines. The CIV emission line strength
depends on both UV and X-ray luminosity, suggesting that the physical mechanism
driving the global Baldwin effect is also associated with X-ray emission.


title:
Quantum groups and quantization of Weyl group symmetries of Painlev\'e
  systems

abstract:
  We shall construct the quantized q-analogues of the birational Weyl group
actions arising from nilpotent Poisson algebras, which are conceptual
generalizations, proposed by Noumi and Yamada, of the B\"acklund
transformations for Painlev\'e equations. Consider a quotient Ore domain of the
lower nilpotent part of a quantized universal enveloping algebra of arbitrary
symmetrizable Kac-Moody type. Then non-integral powers of the image of the
Chevalley generators generate the quantized q-analogue of the birational Weyl
group action. Using the same method, we shall reconstruct the quantized
B\"acklund transformations of q-Painlev\'e equations constructed by Hasegawa.
We shall also prove that any subquotient integral domain of a quantized
universal enveloping algebra of finite or affine type is an Ore domain.


title:
Differential Reduction Algorithms for the All-Order Epsilon Expansion of
  Hypergeometric Functions

abstract:
  Hypergeometric functions provide a useful representation of Feynman diagrams
occuring in precision phenomenology. In dimension regularization, the
epsilon-expansion of these functions about d=4 is required. We discuss the
current status of differential reduction algorithms. As an illustration, we
consider the construction of the all-order epsilon-expansion of the Appell
hypergeometric function about integer values of the parameters and present an
explicit evaluations of the first few terms.


title:
On the importance of hydrodynamic interactions in polyelectrolyte
  electrophoresis

abstract:
  The effect of hydrodynamic interactions on the free-solution electrophoresis
of polyelectrolytes is investigated with coarse-grained molecular dynamics
simulations. By comparing the results to simulations with switched-off
hydrodynamic interactions, we demonstrate their importance in modelling the
experimentally observed behaviour. In order to quantify the hydrodynamic
interactions between the polyelectrolyte and the solution, we present a novel
way to estimate its effective charge. We obtain an effective friction that is
different from the hydrodynamic friction obtained from diffusion measurements.
This effective friction is used to explain the constant electrophoretic
mobility for longer chains. To further emphasize the importance of hydrodynamic
interactions, we apply the model to end-labeled free-solution electrophoresis.


title:
Spin-density induced by electromagnetic wave in two-dimensional electron
  gas with both Rashba and Dresselhaus spin-orbit couplings

abstract:
  We consider the magnetic response of a two-dimensional electron gas (2DEG)
with both Rashba and Dresselhaus spin-orbit coupling to a microwave excitation.
We generalize the results of [A. Shnirman and I. Martin, Europhys. Lett. 78,
27001 (2007).], where pure Rashba coupling was studied. We observe that the
microwave with the in-plane electric field and the out-of-plane magnetic field
creates an out-of-plane spin polarization. The effect is more prominent in
clean systems with resolved spin-orbit-split subbands. Considered as response
to the microwave magnetic field, the spin-orbit contribution to the
magnetization far exceeds the usual Zeeman contribution in the clean limit. The
effect vanishes when the Rashba and the Dresselhaus couplings have equal
strength.


title:
Edge scaling limits for a family of non-Hermitian random matrix
  ensembles

abstract:
  A family of random matrix ensembles interpolating between the GUE and the
Ginibre ensemble of $n\times n$ matrices with iid centered complex Gaussian
entries is considered. The asymptotic spectral distribution in these models is
uniform in an ellipse in the complex plane, which collapses to an interval of
the real line as the degree of non-Hermiticity diminishes. Scaling limit
theorems are proven for the eigenvalue point process at the rightmost edge of
the spectrum, and it is shown that a non-trivial transition occurs between
Poisson and Airy point process statistics when the ratio of the axes of the
supporting ellipse is of order $n^{-1/3}$. In this regime, the family of
limiting probability distributions of the maximum of the real parts of the
eigenvalues interpolates between the Gumbel and Tracy-Widom distributions.


title:
A new line element derived from the variable rest mass in gravitational
  field

abstract:
  This paper presents a new line element based on the assumption of the
variable rest mass in gravitational field, and explores some its implications.
This line element is not a vacuum solution of Einstein's equations, yet it is
sufficiently close to Schwarzschild's line element to be compatible with all of
the experimental and observational measurements made so far to confirm the
three Einstein's predictions. The theory allows radiation and fast particles to
escape from all massive bodies, even from those that in Einstein's general
relativity framework will be black holes. The striking feature of this line
element is the non-existence of black holes.


title:
GRB 070714B - Discovery of the Highest Spectroscopically Confirmed Short
  Burst Redshift

abstract:
  We detect the optical afterglow and host galaxy of GRB 070714B. Our
observations of the afterglow show an initial plateau in the lightcurve for
approximately the first 5 to 25 minutes, then steepening to a powerlaw decay
with index alpha= 0.86 +/- 0.10 for the period between 1 to 24 hours post
burst. This is consistent with the X-ray light-curve which shows an initial
plateau followed by a similar subsequent decay. At late time, we detect a host
galaxy at the location of the optical transient. Gemini Nod & Shuffle
spectroscopic observations of the host show a single emission line at 7167
angstroms which, based on a grizJHK photometric redshift, we conclude is the
3727 angstrom [O II] line. We therefore find a redshift of z=0.923. This
redshift, as well as a subsequent probable spectroscopic redshift determination
of GRB 070429B at z=0.904 by two other groups, significantly exceeds the
previous highest spectroscopically confirmed short burst redshift of z=0.546
for GRB 051221. This dramatically moves back the time at which we know short
bursts were being formed, and suggests that the present evidence for an old
progenitor population may be observationally biased.


title: The Evolution of L and T Dwarfs in Color-Magnitude Diagrams

abstract:
  We present new evolution sequences for very low mass stars, brown dwarfs and
giant planets and use them to explore a variety of influences on the evolution
of these objects. We compare our results with previous work and discuss the
causes of the differences and argue for the importance of the surface boundary
condition provided by atmosphere models including clouds.
  The L- to T-type ultracool dwarf transition can be accommodated within the
Ackerman & Marley (2001) cloud model by varying the cloud sedimentation
parameter. We develop a simple model for the evolution across the L/T
transition. By combining the evolution calculation and our atmosphere models,
we generate colors and magnitudes of synthetic populations of ultracool dwarfs
in the field and in galactic clusters. We focus on near infrared color-
magnitude diagrams (CMDs) and on the nature of the ``second parameter'' that is
responsible for the scatter of colors along the Teff sequence. Variations in
metallicity and cloud parameters, unresolved binaries and possibly a relatively
young population all play a role in defining the spread of brown dwarfs along
the cooling sequence. We find that the transition from cloudy L dwarfs to
cloudless T dwarfs slows down the evolution and causes a pile up of substellar
objects in the transition region, in contradiction with previous studies. We
apply the same model to the Pleiades brown dwarf sequence. Taken at face value,
the Pleiades data suggest that the L/T transition occurs at lower Teff for
lower gravity objects. The simulated populations of brown dwarfs also reveal
that the phase of deuterium burning produces a distinctive feature in CMDs that
should be detectable in ~50-100 Myr old clusters.


title: Uniformly Rotating Homogeneous and Polytropic Rings in Newtonian Gravity

abstract:
  An analytical method is presented for treating the problem of a uniformly
rotating, self-gravitating ring without a central body in Newtonian gravity.
The method is based on an expansion about the thin ring limit, where the
cross-section of the ring tends to a circle. The iterative scheme developed
here is applied to homogeneous rings up to the 20th order and to polytropes
with the index n=1 up to the third order. For other polytropic indices no
analytic solutions are obtainable, but one can apply the method numerically.
However, it is possible to derive a simple formula relating mass to the
integrated pressure to leading order without specifying the equation of state.
Our results are compared with those generated by highly accurate numerical
methods to test their accuracy.


title: Effective particle kinematics from Quantum Gravity

abstract:
  Particles propagating in de Sitter spacetime can be described by the
topological BF $\SO(4,1)$ theory coupled to point charges. Gravitational
interaction between them can be introduced by adding to the action a symmetry
breaking term, which reduces the local gauge symmetry down to $\SO(3,1)$, and
which can be treated as a perturbation. In this paper we focus solely on
topological interactions which corresponds to zeroth order in this perturbative
expansion. We show that in this approximation the system is effectively
described by the $\SO(4,1)$ Chern-Simons theory coupled to particles and living
on the 3 dimensional boundary of space-time. Then, using Alekseev--Malkin
construction we find the effective theory of particles kinematics. We show that
the particles action contains standard kinetic terms and the deformation shows
up in the presence of interaction terms. The strength of the interactions is
proportional to deformation parameter, identified with Planck mass scale.


title:
On Bogovski\u{\i} and regularized Poincar\'e integral operators for de
  Rham complexes on Lipschitz domains

abstract:
  We study integral operators related to a regularized version of the classical
Poincar\'e path integral and the adjoint class generalizing Bogovski\u{\i}'s
integral operator, acting on differential forms in $R^n$. We prove that these
operators are pseudodifferential operators of order -1. The Poincar\'e-type
operators map polynomials to polynomials and can have applications in finite
element analysis. For a domain starlike with respect to a ball, the special
support properties of the operators imply regularity for the de Rham complex
without boundary conditions (using Poincar\'e-type operators) and with full
Dirichlet boundary conditions (using Bogovski\u{\i}-type operators). For
bounded Lipschitz domains, the same regularity results hold, and in addition we
show that the cohomology spaces can always be represented by $C^\infty$
functions.


title:
Dual mapping between the antisymmetric tensor matter field and the
  Kalb-Ramond field

abstract:
  In this work we present a dual mapping between the Kalb-Ramond and
antisymmetric tensor matter (ATM) field actions. Our procedure shows that the
correlation functions associated with both the Noether current and the
topological current are equivalent.


title: Hadronic Final States and QCD: Summary

abstract:
  A summary of new experimental results and recent theoretical developments
discussed in the "Hadronic Final States and QCD" working group is presented.


title: On the non-integrability of the Popowicz peakon system

abstract:
  We consider a coupled system of Hamiltonian partial differential equations
introduced by Popowicz, which has the appearance of a two-field coupling
between the Camassa-Holm and Degasperis-Procesi equations. The latter equations
are both known to be integrable, and admit peaked soliton (peakon) solutions
with discontinuous derivatives at the peaks. A combination of a reciprocal
transformation with Painlev\'e analysis provides strong evidence that the
Popowicz system is non-integrable. Nevertheless, we are able to construct exact
travelling wave solutions in terms of an elliptic integral, together with a
degenerate travelling wave corresponding to a single peakon. We also describe
the dynamics of N-peakon solutions, which is given in terms of an Hamiltonian
system on a phase space of dimension 3N.


title:
Explicit double shuffle relations and a generalization of Euler's
  decomposition formula

abstract:
  We give an explicit formula for the shuffle relation in a general double
shuffle framework that specializes to double shuffle relations of multiple zeta
values and multiple polylogarithms. As an application, we generalize the
well-known decomposition formula of Euler that expresses the product of two
Riemann zeta values as a sum of double zeta values to a formula that expresses
the product of two multiple polylogarithm values as a sum of other multiple
polylogarithm values.


title:
Characterizations of discrete Sugeno integrals as polynomial functions
  over distributive lattices

abstract:
  We give several characterizations of discrete Sugeno integrals over bounded
distributive lattices, as particular cases of lattice polynomial functions,
that is, functions which can be represented in the language of bounded lattices
using variables and constants. We also consider the subclass of term functions
as well as the classes of symmetric polynomial functions and weighted minimum
and maximum functions, and present their characterizations, accordingly.
Moreover, we discuss normal form representations of these functions.


title:
Density-matrix renormalization group methods for momentum- and
  frequency-resolved dynamical correlation functions

abstract:
  Several density-matrix renormalization group methods have been proposed to
compute the momentum- and frequency-resolved dynamical correlation functions of
low-dimensional strongly correlated systems. The most relevant approaches are
discussed in this contribution. Their applications in various studies of
quasi-one-dimensional strongly correlated systems (spin chains, itinerant
electron systems, electron-phonon systems) are reviewed.


title:
Magnetization and spin dynamics of a Cr-based magnetic cluster:
  Cr$_{7}$Ni

abstract:
  We study the magnetization and the spin dynamics of the Cr$_7$Ni ring-shaped
magnetic cluster. Measurements of the magnetization at high pulsed fields and
low temperature are compared to calculations and show that the spin Hamiltonian
approach provides a good description of Cr$_7$Ni magnetic molecule. In
addition, the phonon-induced relaxation dynamics of molecular observables has
been investigated. By assuming the spin-phonon coupling to take place through
the modulation of the local crystal fields, it is possible to evaluate the
decay of fluctuations of two generic molecular observables. The nuclear
spin-lattice relaxation rate $1/T_1$ directly probes such fluctuations, and
allows to determine the magnetoelastic coupling strength.


title:
On the photofragmentation of SF$_2^+$: Experimental evidence for a
  predissociation channel

abstract:
  We report on the first observation of the photofragmentation dynamics of
SF$_2^+$. With the aid of state-of-the-art ab initio calculations on the
low-lying excited cationic states of SF$_2^+$ performed by Lee et al. [J. Chem.
Phys. 125, 104304 (2006)], a predissociation channel of SF$_2^+$ is evidenced
by means of resonance-enhanced multilphoton ionization spectroscopy. This work
represents a second experimental investigation on the low-lying excited
cationic states of SF$_2^+$. [The first one is the He I photoelectron spectrum
of SF$_2^+$ reported by de Leeuw et al. three decades ago, see Chem. Phys. 34,
287 (1978).]


title:
Diffeomorphism Invariance in the Hamiltonian formulation of General
  Relativity

abstract:
  It is shown that when the Einstein-Hilbert Lagrangian is considered without
any non-covariant modifications or change of variables, its Hamiltonian
formulation leads to results consistent with principles of General Relativity.
The first-class constraints of such a Hamiltonian formulation, with the metric
tensor taken as a canonical variable, allow one to derive the generator of
gauge transformations, which directly leads to diffeomorphism invariance. The
given Hamiltonian formulation preserves general covariance of the
transformations derivable from it. This characteristic should be used as the
crucial consistency requirement that must be met by any Hamiltonian formulation
of General Relativity.


title: Is there a Supermassive Black Hole at the Center of the Milky Way?

abstract:
  This review outlines the observations that now provide an overwhelming
scientific case that the center of our Milky Way Galaxy harbors a supermassive
black hole. Observations at infrared wavelength trace stars that orbit about a
common focal position and require a central mass (M) of 4 million solar masses
within a radius of 100 Astronomical Units. Orbital speeds have been observed to
exceed 5,000 km/s. At the focal position there is an extremely compact radio
source (Sgr A*), whose apparent size is near the Schwarzschild radius
(2GM/c^2). This radio source is motionless at the ~1 km/s level at the
dynamical center of the Galaxy. The mass density required by these observations
is now approaching the ultimate limit of a supermassive black hole within the
last stable orbit for matter near the event horizon.


title: Inclusive inelastic electron scattering from nuclei

abstract:
  Inclusive electron scattering from nuclei at large x and $Q^2$ is the result
of a reaction mechanism that includes both quasi--elastic scattering from
nucleons and deep inelastic scattering from the quark constituents of the
nucleons. Data in this regime can be used to study a wide variety of topics,
including the extraction of nuclear momentum distributions, the influence of
final state interactions and the approach to $y$-scaling, the strength of
nucleon-nucleon correlations, and the approach to $x$- scaling, to name a few.
Selected results from the recent experiment E02-019 at the Thomas Jefferson
National Accelerator Facility will be shown and their relevance discussed.


title:
Gromov-Witten theory of orbicurves, the space of tri-polynomials and
  Symplectic Field Theory of Seifert fibrations

abstract:
  We compute, with Symplectic Field Theory techniques, the Gromov-Witten theory
of the complex projective line with orbifold points. A natural subclass of
these orbifolds, the ones with polynomial quantum cohomology, gives rise to a
family of (polynomial) Frobenius manifolds and integrable systems of
Hamiltonian PDEs, which extend the (dispersionless) bigraded Toda hierarchy. We
then define a Frobenius structure on the spaces of polynomials in three complex
variables of the form F(x,y,z)= -xyz+P_1(x)+P_2(y)+P_3(z) which contains as
special cases the ones constructed on the space of Laurent polynomials. We
prove a mirror theorem stating that these Frobenius structures are isomorphic
to the ones found before for polynomial P1-orbifolds. Finally we link rational
Symplectic Field Theory of Seifert fibrations over S^2 and three singular
fibers with orbifold Gromov-Witten invariants of the base, extending a known
result valid in the smooth case.


title: Subleading and non-holomorphic corrections to N=2 BPS black hole entropy

abstract:
  BPS black hole degeneracies can be expressed in terms of an inverse Laplace
transform of a partition function based on a mixed electric/magnetic ensemble,
which involves a non-trivial integration measure. This measure has been
evaluated for black holes with various degrees of supersymmetry and for N=4
supersymmetric black holes all results agree. It generally receives
contributions from non-holomorphic corrections. An explicit evaluation of these
corrections in the context of the effective action of the FHSV model reveals
that these are related to, but quantitatively different from, the
non-holomorphic corrections to the topological string, indicating that the
relation between the twisted partition functions of the latter and the
effective action is more subtle than has so far been envisaged. The effective
action result leads to a duality invariant BPS free energy and arguments are
presented for the existence of consistent non-holomorphic deformations of
special geometry that can account for these effects. A prediction is given for
the measure based on semiclassical arguments for a class of N=2 black holes.
Furthermore an attempt is made to confront some of the results of this paper to
a recent proposal for the microstate degeneracies of the STU model.


title: Liberation of orthogonal Lie groups

abstract:
  We show that under suitable assumptions, we have a one-to-one correspondence
between classical groups and free quantum groups, in the compact orthogonal
case. We classify the groups under correspondence, with the result that there
are exactly 6 of them: $O_n,S_n,H_n,B_n,S_n',B_n'$. We investigate the
representation theory aspects of the correspondence, with the result that for
$O_n,S_n,H_n,B_n$, this is compatible with the Bercovici-Pata bijection.
Finally, we discuss some more general classification problems in the compact
orthogonal case, notably with the construction of a new quantum group.


title: Open-chain transfer matrices for AdS/CFT

abstract:
  We extend Sklyanin's construction of commuting open-chain transfer matrices
to the SU(2|2) bulk and boundary S-matrices of AdS/CFT. Using the graded
version of the S-matrices leads to a transfer matrix of particularly simple
form. We also find an SU(1|1) boundary S-matrix which has one free boundary
parameter.


title:
Identification of the TW Hya Association member 2M1235$-$39: a tertiary
  component of the HR 4796 system

abstract:
  The association of the late-type star 2MASS J12354893-3950245 (2M1235-39)
with a bright X-ray source detected serendipitously by ROSAT and XMM-Newton,
combined with its proximity to the well-studied (A+M binary) system HR 4796,
suggests this star is a member of the TW Hya Association (TWA). To test this
hypothesis, we used optical spectroscopy to establish the Li and H-alpha line
strengths and spectral type of 2M1235-39, and determined its proper motion via
optical imaging. The Li absorption and H-alpha emission line strengths of
2M1235-39, its near-IR and X-ray fluxes, and its proper motion all indicate
that 2M1235-39 is a TWA member. Most likely this star is a wide (13,500 AU)
separation, low-mass (M4.5), tertiary component of the HR 4796 system.


title: On the Stability of Black Holes at the LHC

abstract:
  The eventual production of mini black holes by proton-proton collisions at
the LHC is predicted by theories with large extra dimensions resolvable at the
Tev scale of energies. It is expected that these black holes evaporate shortly
after its production as a consequence of the Hawking radiation. We show that
for theories based on the ADS/CFT correspondence, the produced black holes may
have an unstable horizon, which grows proportionally to the square of the
distance to the collision point.


title: Quantum-entanglement aspects of polaron systems

abstract:
  We describe quantum entanglement inherent to the polaron ground states of
coupled electron-phonon (or, more generally, particle-phonon) systems based on
a model comprising both local (Holstein-type) and nonlocal (Peierls-type)
coupling. We study this model using a variational method supplemented by the
exact numerical diagonalization on a system of finite size. By way of
subsequent numerical diagonalization of the reduced density matrix, we
determine the particle-phonon entanglement as given by the von Neumann and
linear entropies. Our results are strongly indicative of the intimate
relationship between the particle localization/delocalization and the
particle-phonon entanglement. In particular, we find a compelling evidence for
the existence of a nonanalyticity in the entanglement entropies with respect to
the Peierls-coupling strength. The occurrence of such nonanalyticity -- not
accompanied by an actual quantum phase transition -- reinforces analogous
conclusion drawn in several recent studies of entanglement in the realm of
quantum-dissipative systems. In addition, we demonstrate that the entanglement
entropies saturate inside the self-trapped region where the small-polaron
states are nearly maximally mixed.


title: Towards real-time community detection in large networks

abstract:
  The recent boom of large-scale Online Social Networks (OSNs) both enables and
necessitates the use of parallelisable and scalable computational techniques
for their analysis. We examine the problem of real-time community detection and
a recently proposed linear time - O(m) on a network with m edges - label
propagation or "epidemic" community detection algorithm. We identify
characteristics and drawbacks of the algorithm and extend it by incorporating
different heuristics to facilitate reliable and multifunctional real-time
community detection. With limited computational resources, we employ the
algorithm on OSN data with 1 million nodes and about 58 million directed edges.
Experiments and benchmarks reveal that the extended algorithm is not only
faster but its community detection accuracy is compared favourably over popular
modularity-gain optimization algorithms known to suffer from their resolution
limits.


title:
A connection between the stochastic heat equation and fractional
  Brownian motion, and a simple proof of a result of Talagrand

abstract:
  We give a new representation of fractional Brownian motion with Hurst
parameter H<=1/2 using stochastic partial differential equations. This
representation allows us to use the Markov property and time reversal, tools
which are not usually available for fractional Brownian motion. We then give
simple proofs that fractional Brownian motion does not hit points in the
critical dimension, and that it does not have double points in the critical
dimension. These facts were already known, but our proofs are quite simple and
use some ideas of Levy.


title: The Laguerre polynomials preserve real-rootedness

abstract:
  The linear transformation that sends $x^n$ to the n'th Laguerre polynomial
preserves real-rootedness.


title: Basin boundary, edge of chaos, and edge state in a two-dimensional model

abstract:
  In shear flows like pipe flow and plane Couette flow there is an extended
range of parameters where linearly stable laminar flow coexists with a
transient turbulent dynamics. When increasing the amplitude of a perturbation
on top of the laminar flow, one notes a a qualitative change in its lifetime,
from smoothly varying and short one on the laminar side to sensitively
dependent on initial conditions and long on the turbulent side. The point of
transition defines a point on the edge of chaos. Since it is defined via the
lifetimes, the edge of chaos can also be used in situations when the turbulence
is not persistent. It then generalises the concept of basin boundaries, which
separate two coexisting attractors, to cases where the dynamics on one side
shows transient chaos and almost all trajectories eventually end up on the
other side. In this paper we analyse a two-dimensional map which captures many
of the features identified in laboratory experiments and direct numerical
simulations of hydrodynamic flows. The analysis of the map shows that different
dynamical situations in the edge of chaos can be combined with different
dynamical situations in the turbulent region. Consequently, the model can be
used to develop and test further characterisations that are also applicable to
realistic flows.


title: Operator-valued Fourier multipliers in Besov spaces and its applications

abstract:
  The present paper, is devoted to investigation of operator--valued Fourier
multiplier theorems from $B_{q_{1},r}^{s}$ to $B_{q_{2},r}^{s}$, optimal
embedding of Besov spaces, the separability and positivity of differential
operators. Here, we show that these differential operators generate analytic
semigroup.


title: Scanning tunneling microscopy study of the CeTe3 charge density wave

abstract:
  We have studied the nature of the surface charge distribution in CeTe3. This
is a simple, cleavable, layered material with a robust one-dimensional
incommensurate charge density wave (CDW). Scanning tunneling microscopy (STM)
has been applied on the exposed surface of a cleaved single crystal. At 77 K,
the STM images show both the atomic lattice of surface Te atoms arranged in a
square net and the CDW modulations oriented at 45 degrees with respect to the
Te net. Fourier transform of the STM data shows Te square lattice peaks, and
peaks related to the CDW oriented at 45 degrees to the lattice peaks. In
addition, clear peaks are present, consistent with subsurface structure and
wave vector mixing effects. These data are supported by electronic structure
calculations, which show that the subsurface signal most likely arises from a
lattice of Ce atoms situated 2.53 angstroms below the surface Te net.


title:
Nonclassical Correlation of Polarization Entangled Photons in a
  Biexciton-Exciton Cascade

abstract:
  We develop a theoretical model to study the Intensity-Intensity correlation
of polarization entangled photons emitted in a biexciton-exciton cascade. We
calculate the degree of correlation and show how polarization correlation are
affected by the presence of dephasing and energy level splitting of the
excitonic states. Our theoretical calculations are in agreement with the recent
observation of polarization dependent Intensity-Intensity correlations from a
single semiconductor quantum dot [R. M. Stevenson et. al., Nature 439, 179
(2006)] . Our model can be extended to study polarization entangled photon
emission in coupled quantum dot systems.


title:
Galaxy populations in the Antlia cluster. II. Compact elliptical galaxy
  candidates

abstract:
  We present a photometric analysis of four galaxies classified as compact
elliptical (cE) galaxies in the FS90 Antlia Group catalogue. Only 6 members of
this rare type of galaxies are known until now. Using data in various
photometric systems, we measured brightness and colour profiles, as well as
structural parameters. By comparing them with those of other galaxies in the
Antlia cluster, as well as with confirmed cE galaxies from the literature, we
found that two of the FS90 cE candidates, albeit being spectroscopically
confirmed Antlia members, are not cE galaxies. However, one of these objects
presents strong ellipticity and position angle variations that resemble those
already reported for M32, leading us to speculate about this kind of objects
being progenitors of cE galaxies. The other two FS90 cE candidates, for which
radial velocities are not available, match some features typical of cE galaxies
like being close in projection to a larger galaxy, displaying flat colour
profiles, and having a high degree of compactness. Only one of the remaining cE
candidates shows a high central surface brightness, two components in its
brightness profile, distinct changes in ellipticity and position angle where
the outer component begins to dominate, and seems to follow the same trend as
other confirmed cE galaxies in a luminosity versus mean effective surface
brightness diagram. Moreover, it shows a distorted inner structure with similar
characteristics to those found by simulations of interacting galaxies, and an
extremely faint structure that seems to link this object with one of the Antlia
dominant galaxies, has been detected in MOSAIC-CTIO, FORS1-VLT, and ACS-HST
images. The cE nature of this galaxy as well as the possible interaction with
its bright companion, still have to be confirmed through spectroscopy.


title:
Fitting the Gamma-Ray Spectrum from Dark Matter with DMFIT: GLAST and
  the Galactic Center Region

abstract:
  We study the potential of GLAST to unveil particle dark matter properties
with gamma-ray observations of the Galactic center region. We present full
GLAST simulations including all gamma-ray sources known to date in a region of
4 degrees around the Galactic center, in addition to the diffuse gamma-ray
background and to the dark matter signal. We introduce DMFIT, a tool that
allows one to fit gamma-ray emission from pair-annihilation of generic particle
dark matter models and to extract information on the mass, normalization and
annihilation branching ratios into Standard Model final states. We assess the
impact and systematic effects of background modeling and theoretical priors on
the reconstruction of dark matter particle properties. Our detailed simulations
demonstrate that for some well motivated supersymmetric dark matter setups with
one year of GLAST data it will be possible not only to significantly detect a
dark matter signal over background, but also to estimate the dark matter mass
and its dominant pair-annihilation mode.


title:
Structure and star formation in galaxies out to z=3: evidence for
  surface density dependent evolution and upsizing

abstract:
  We present an analysis of galaxies in the CDF-South. We find a tight relation
to z=3 between color and size at a given mass, with red galaxies being small,
and blue galaxies being large. We show that the relation is driven by stellar
surface density or inferred velocity dispersion: galaxies with high surface
density are red and have low specific star formation rates, and galaxies with
low surface density are blue and have high specific star formation rates.
Surface density and inferred velocity dispersion are better correlated with
specific star formation rate and color than stellar mass. Hence stellar mass by
itself is not a good predictor of the star formation history of galaxies. In
general, galaxies at a given surface density have higher specific star
formation rates at higher redshift. Specifically, galaxies with a surface
density of 1-3 10^9 Msun/kpc^2 are "red and dead" at low redshift,
approximately 50% are forming stars at z=1, and almost all are forming stars by
z=2. This provides direct additional evidence for the late evolution of
galaxies onto the red sequence. The sizes of galaxies at a given mass evolve
like 1/(1+z)^(0.59 +- 0.10). Hence galaxies undergo significant upsizing in
their history. The size evolution is fastest for the highest mass galaxies, and
quiescent galaxies. The persistence of the structural relations from z=0 to
z=2.5, and the upsizing of galaxies imply that a relation analogous to the
Hubble sequence exists out to z=2.5, and possibly beyond. The star forming
galaxies at z >= 1.5 are quite different from star forming galaxies at z=0, as
they have likely very high gas fractions, and star formation time scales
comparable to the orbital time.


title: Ubiquitous Water Masers in Nearby Star-Forming Galaxies

abstract:
  We report the detection of water maser emission from four nearby galaxies
hosting ultradense HII (UDHII) regions, He 2-10, the Antennae galaxies (NGC
4038/4039), NGC 4214, and NGC 5253, with the Green Bank Telescope. Our
detection rate is 100%, and all of these H2O "kilomasers" (L(H2O) < 10 L_sun)
are located toward regions of known star formation as traced by UDHII regions
and bright 24 micron emission. Some of the newly discovered H2O masers have
luminosities 1-2 orders of magnitude less than previous extragalactic studies
and the same order of magnitude as those typical of Galactic massive
star-forming regions. The unusual success of this minisurvey suggests that H2O
maser emission may be very common in starburst galaxies, and the paucity of
detections to date is due to a lack of sufficient sensitivity. While the galaxy
sample was selected by the presence of UDHII regions, and the UDHII regions lie
within the telescope beam, in the absence of H2O spectral line maps the
connection between H2O masers and UDHII regions has not yet been demonstrated.


title: A discontinuity in the low-mass IMF - the case of high multiplicity

abstract:
  The empirical binary properties of brown dwarfs (BDs) differ from those of
normal stars suggesting BDs form a separate population. Recent work by Thies &
Kroupa revealed a discontinuity of the initial mass function (IMF) in the
very-low-mass star regime under the assumption of a low multiplicity of BDs of
about 15 per cent. However, previous observations had suggested that the
multiplicity of BDs may be significantly higher, up to 45 per cent. This
contribution investigates the implication of a high BD multiplicity on the
appearance of the IMF for the Orion Nebula Cluster, Taurus-Auriga, IC 348 and
the Pleiades. We show that the discontinuity remains pronounced even if the
observed MF appears to be continuous, even for a BD binary fraction as high as
60%. We find no evidence for a variation of the BD IMF with star-forming
conditions. The BD IMF has a power-law index alpha = +0.3 and about two BDs
form per 10 low-mass stars assuming equal-mass pairing of BDs.


title: DLA kinematics and outflows from starburst galaxies

abstract:
  We present results from a numerical study of the multiphase interstellar
medium in sub-Lyman-break galaxy protogalactic clumps. Such clumps are abundant
at z=3 and are thought to be a major contributor to damped Ly-alpha absorption.
We model the formation of winds from these clumps and show that during star
formation episodes they feature outflows with neutral gas velocity widths up to
several hundred km/s. Such outflows are consistent with the observed
high-velocity dispersion in DLAs. In our models thermal energy feedback from
winds and supernovae results in efficient outflows only when cold (~ 300 K),
dense (> 100 msun/pc^3) clouds are resolved at grid resolution of 12 pc. At
lower 24 pc resolution the first signs of the multiphase medium are spotted;
however, at this low resolution thermal injection of feedback energy cannot yet
create hot expanding bubbles around star-forming regions -- instead feedback
tends to erase high-density peaks and suppress star formation. At 12 pc
resolution feedback compresses cold clouds, often without disrupting the
ongoing star formation; at the same time a larger fraction of feedback energy
is channeled into low-density bubbles and winds. These winds often entrain
compact neutral clumps which produce multi-component metal absorption lines.


title: Can entropy save bacteria?

abstract:
  This article presents a physical biology approach to understanding
organization and segregation of bacterial chromosomes. The author uses a
"piston" analogy for bacterial chromosomes in a cell, which leads to a phase
diagram for the organization of two athermal chains confined in a closed
geometry characterized by two length scales (length and width). When applied to
rod-shaped bacteria such as Escherichia coli, this phase diagram predicts that,
despite strong confinement, duplicated chromosomes will demix, i.e., there
exists a primordial physical driving force for chromosome segregation. The
author discusses segregation of duplicating chromosomes using the
concentric-shell model, which predicts that newly synthesized DNA will be found
in the periphery of the chromosome during replication. In contrast to
chromosomes, these results suggest that most plasmids will be randomly
distributed inside the cell because of their small sizes. An active
partitioning system is therefore required for accurate segregation of low-copy
number plasmids. Implications of these results are also sketched, e.g., on the
role of proteins, segregation mechanisms for bacteria of diverse shapes, cell
cycle of an artificial cell, and evolution.


title:
Berry Phase and the Breakdown of the Quantum to Classical Mapping for
  the Quantum Critical Point of the Bose-Fermi Kondo model

abstract:
  The phase diagram of the Bose-Fermi Kondo model contains an SU(2)-invariant
Kondo-screened phase separated by a continuous quantum phase transition from a
Kondo-destroyed local moment phase. We analyze the effect of the Berry phase
term of the spin path integral on the quantum critical properties of this
quantum impurity model. For a range of the power-law exponent characterizing
the spectral density of the dissipative bosonic bath, neglecting the influence
of the Berry phase term makes the fixed point Gaussian. For the same range of
the spectral density exponent, incorporating the Berry phase term leads instead
to an interacting fixed point, for which a quantum to classical mapping breaks
down. Some general implications of our results are discussed.


title:
The Extended Star Formation History of the Andromeda Spheroid at 35 Kpc
  on the Minor Axis

abstract:
  Using the HST ACS, we have obtained deep optical images reaching well below
the oldest main sequence turnoff in fields on the southeast minor-axis of the
Andromeda Galaxy, 35 kpc from the nucleus. These data probe the star formation
history in the extended halo of Andromeda -- that region beyond 30 kpc that
appears both chemically and morphologically distinct from the metal-rich,
highly-disturbed inner spheroid. The present data, together with our previous
data for fields at 11 and 21 kpc, do not show a simple trend toward older ages
and lower metallicities, as one might expect for populations further removed
from the obvious disturbances of the inner spheroid. Specifically, the mean
ages and [Fe/H] values at 11 kpc, 21 kpc, and 35 kpc are 9.7 Gyr and -0.65,
11.0 Gyr and -0.87, and 10.5 Gyr and -0.98, respectively. In the best-fit model
of the 35 kpc population, one third of the stars are younger than 10 Gyr, while
only ~10% of the stars are truly ancient and metal-poor. The extended halo thus
exhibits clear evidence of its hierarchical assembly, and the contribution from
any classical halo formed via early monolithic collapse must be small.


title: Numerical Simulation of Particle Flow in a Sand Trap

abstract:
  Sand traps are used to measure Aeolian flux. Since they modify the
surrounding wind velocity field their gauging represents an important
challenge. We use numerical simulations under the assumption of homogeneous
turbulence based on FLUENT to systematically study the flow field and trapping
efficiency of one of the most common devices based on a hollow cylinder with
two slits. In particular, we investigate the dependence on the wind speed, the
Stokes number, the permeability of the membrane on the slit and the saltation
height.


title:
T-duality for open strings in the presence of backgrounds and
  noncommutativity

abstract:
  We investigate the effect of T-duality on noncommutativity. Starting with
open strings ending on a D2-brane wrapped on a $T^2$ torus in the presence of a
Kalb Ramond field, we consider Buscher transformations on the coordinates and
background. We find that the dual system is commutative. We also study
alternative transformations that can preserve noncommutativity.


title: The Chemical and Ionization Conditions in Weak Mg II Absorbers

abstract:
  We present an analysis of the chemical and ionization conditions in a sample
of 100 weak Mg II absorbers identified in the VLT/UVES archive of quasar
spectra. Using a host of low ionization lines associated with each absorber in
this sample, and on the basis of ionization models, we infer that the
metallicity in a significant fraction of weak Mg II clouds is constrained to
values of solar or higher, if they are sub-Lyman limit systems. Based on the
observed constraints, we present a physical picture in which weak Mg II
absorbers are predominantly tracing two different astrophysical
processes/structures. A significant population of weak Mg II clouds, those in
which N(Fe II) is much less than N(Mg II), identified at both low (z ~ 1) and
high (z ~ 2) redshift, are potentially tracing gas in the extended halos of
galaxies, analogous to the Galactic high velocity clouds. These absorbers might
correspond to alpha-enhanced interstellar gas expelled from star-forming
galaxies, in correlated supernova events. On the other hand, N(FeII)
approximately equal to N(Mg II) clouds, which are prevalent only at lower
redshifts (z < 1.5), must be tracing Type Ia enriched gas in small, high
metallicity pockets in dwarf galaxies, tidal debris, or other intergalactic
structures.


title: Squeezing Out the Entropy of Fermions in Optical Lattices

abstract:
  At present, there is considerable interest in using atomic fermions in
optical lattices to emulate the mathematical models that have been used to
study strongly correlated electronic systems. Some of these models, such as the
two dimensional fermion Hubbard model, are notoriously difficult to solve, and
their key properties remain controversial despite decades of studies. It is
hoped that the emulation experiments will shed light on some of these long
standing problems. A successful emulation, however, requires reaching
temperatures as low as $10^{-12}$K and beyond, with entropy per particle far
lower than what can be achieved today. Achieving such low entropy states is an
essential step and a grand challenge of the whole emulation enterprise. In this
paper, we point out a method to literally squeeze the entropy out from a Fermi
gas into a surrounding Bose-Einstein condensed gas (BEC), which acts as a heat
reservoir. This method allows one to reduce the entropy per particle of a
lattice Fermi gas to a few percent of the lowest value obtainable today.


title:
Possible Superconductivity in Fe-Sb Based Materials: Density Functional
  Study of LiFeSb

abstract:
  We investigate the electronic and other properties of the hypothetical
compound LiFeSb in relation to superconducting LiFeAs and FeSe using density
functional calculations. The results show that LiFeSb in the LiFeAs structure
would be dynamically stable in the sense of having no unstable phonon modes,
and would have very similar electronic and magnetic properties to the layered
Fe based superconductors. Importantly, a very similar structure for the Fermi
surface and a spin density wave related to but stronger than that in the
corresponding As compound is found. These results are indicative of possible
superconductivity analogous to the Fe-As based compounds if the spin density
wave can be suppressed by doping or other means. Prospects for synthesizing
this material in pure form or in solid solution with FeTe are discussed.


title:
Report on the "Secure Vehicular Communications: Results and Challenges
  Ahead" Workshop

abstract:
  This is a report and a collection of abstracts from the Feb. 2008 Lausanne
Workshop on Secure Vehicular Communication Systems.


title:
Cosmology-Independent Distance Moduli of 42 Gamma-Ray Bursts between
  Redshift of 1.44 and 6.60

abstract:
  This report is an update and extension of our paper accepted for publication
in ApJ (arXiv:0802.4262). Since objects at the same redshift should have the
same luminosity distance and the distance moduli of type Ia supernovae (SNe Ia)
obtained directly from observations are completely cosmology independent, we
obtain the distance modulus of a gamma-ray burst (GRB) at a given redshift by
interpolating or iterating from the Hubble diagram of SNe Ia. Then we calibrate
five GRB relations without assuming a particular cosmological model, from
different regression methods, and construct the GRB Hubble diagram to constrain
cosmological parameters. Based upon these relations we list the
cosmology-independent distance moduli of 42 GRBs between redshift of 1.44 and
6.60, with the 1-$\sigma$ uncertainties of 1-3%.


title: A multi-channel Poissonian model for multi-parton scatterings

abstract:
  Multiple parton interactions are typically implemented in Montecarlo codes by
assuming a Poissonian distribution of collisions with average number depending
on the impact parameter. A possible generalization, which links the process to
hadronic diffraction, is shortly discussed.


title: Some remarks on the Stanley's depth for multigraded modules

abstract:
  We show that the Stanley's conjecture holds for any multigraded $S$-module
$M$ with $\sdepth(M)=0$, where $S=K[x_1,...,x_n]$. Also, we give some bounds
for the Stanley depth of the powers of the maximal irrelevant ideal in $S$.


title: Invariant conformal metrics on S^n

abstract:
  In this paper we use the relationship between conformal metrics on the sphere
and horospherically convex hypersurfaces in the hyperbolic space for giving
sufficient conditions on a conformal metric to be radial under some constrain
on the eigenvalues of its Schouten tensor. Also, we study conformal metrics on
the sphere which are invariant by a $k-$parameter subgroup of conformal
diffeomorphisms of the sphere, giving a bound on its maximum dimension.
  Moreover, we classify conformal metrics on the sphere whose eigenvalues of
the Shouten tensor are all constant (we call them \emph{isoparametric conformal
metrics}), and we use a classification result for radial conformal metrics
which are solution of some $\sigma _k -$Yamabe type problem for obtaining
existence of rotational spheres and Delaunay-type hypersurfaces for some
classes of Weingarten hypersurfaces in $\h ^{n+1}$.


title: Distributed Source Coding using Abelian Group Codes

abstract:
  In this work, we consider a distributed source coding problem with a joint
distortion criterion depending on the sources and the reconstruction. This
includes as a special case the problem of computing a function of the sources
to within some distortion and also the classic Slepian-Wolf problem,
Berger-Tung problem, Wyner-Ziv problem, Yeung-Berger problem and the
Ahlswede-Korner-Wyner problem. While the prevalent trend in information theory
has been to prove achievability results using Shannon's random coding
arguments, using structured random codes offer rate gains over unstructured
random codes for many problems. Motivated by this, we present a new achievable
rate-distortion region for this problem for discrete memoryless sources based
on "good" structured random nested codes built over abelian groups. We
demonstrate rate gains for this problem over traditional coding schemes using
random unstructured codes. For certain sources and distortion functions, the
new rate region is strictly bigger than the Berger-Tung rate region, which has
been the best known achievable rate region for this problem till now. Further,
there is no known unstructured random coding scheme that achieves these rate
gains. Achievable performance limits for single-user source coding using
abelian group codes are also obtained as parts of the proof of the main coding
theorem. As a corollary, we also prove that nested linear codes achieve the
Shannon rate-distortion bound in the single-user setting.


title:
A basic limitation on inferring phylogenies by pairwise sequence
  comparisons

abstract:
  Distance-based approaches in phylogenetics such as Neighbor-Joining are a
fast and popular approach for building trees. These methods take pairs of
sequences from them construct a value that, in expectation, is additive under a
stochastic model of site substitution. Most models assume a distribution of
rates across sites, often based on a gamma distribution. Provided the (shape)
parameter of this distribution is known, the method can correctly reconstruct
the tree. However, if the shape parameter is not known then we show that
topologically different trees, with different shape parameters and associated
positive branch lengths, can lead to exactly matching distributions on pairwise
site patterns between all pairs of taxa. Thus, one could not distinguish
between the two trees using pairs of sequences without some prior knowledge of
the shape parameter. More surprisingly, this can happen for {\em any} choice of
distinct shape parameters on the two trees, and thus the result is not peculiar
to a particular or contrived selection of the shape parameters. On a positive
note, we point out known conditions where identifiability can be restored
(namely, when the branch lengths are clocklike, or if methods such as maximum
likelihood are used).


title:
Combined Chandra, XMM-Newton and Hubble Space Telescope observations of
  the Galactic globular cluster NGC 2808

abstract:
  Using new Chandra X-ray observations and existing XMM-Newton X-ray and Hubble
far ultraviolet observations, we aim to detect and identify the faint X-ray
sources belonging to the Galactic globular cluster NGC 2808 in order to
understand their role in the evolution of globular clusters. We present a
Chandra X-ray observation of the Galactic globular cluster NGC 2808. We
classify the X-ray sources associated with the cluster by analysing their
colours and variability. Previous observations with XMM-Newton and far
ultraviolet observations with the Hubble Space Telescope are re-investigated to
help identify the Chandra sources associated with the cluster. We compare our
results to population synthesis models and observations of other Galactic
globular clusters. We detect 113 sources, of which 16 fall inside the half-mass
radius of NGC 2808 and are concentrated towards the cluster core. From
statistical analysis, these 16 sources are very likely to be linked to the
cluster. We detect short-term (1 day) variability in X-rays for 7 sources, of
which 2 fall inside the half-mass radius, and long-term (28 months) variability
for 10 further sources, of which 2 fall inside the half-mass radius.
Ultraviolet counterparts are found for 8 Chandra sources in the core, of which
2 have good matching probabilities and have ultraviolet properties expected for
cataclysmic variables. We find one likely neutron star-quiescent low-mass X-ray
binary and 7 cataclysmic variable candidates in the core of NGC 2808. The other
8 sources are cataclysmic variable candidates, but some could possibly be
active binaries or millisecond pulsars. We find a possible deficit of X-ray
sources compared to 47 Tuc which could be related to the metallicity content
and the complexity of the evolution of NGC 2808.


title: Multitask Efficiencies in the Decision Tree Model

abstract:
  In Direct Sum problems [KRW], one tries to show that for a given
computational model, the complexity of computing a collection of finite
functions on independent inputs is approximately the sum of their individual
complexities. In this paper, by contrast, we study the diversity of ways in
which the joint computational complexity can behave when all the functions are
evaluated on a common input. We focus on the deterministic decision tree model,
with depth as the complexity measure; in this model we prove a result to the
effect that the 'obvious' constraints on joint computational complexity are
essentially the only ones.
  The proof uses an intriguing new type of cryptographic data structure called
a `mystery bin' which we construct using a small polynomial separation between
deterministic and unambiguous query complexity shown by Savicky. We also pose a
variant of the Direct Sum Conjecture of [KRW] which, if proved for a single
family of functions, could yield an analogous result for models such as the
communication model.


title: Electromagnetic Dipole Strength in Transitional Nuclei

abstract:
  Electromagnetic dipole absorption cross-sections of transitional nuclei with
large-amplitude shape fluctuations are calculated in a microscopic way by
introducing the concept of Instantaneous Shape Sampling. The concept bases on
the slow shape dynamics as compared to the fast dipole vibrations. The
elctromagnetic dipole strength is calculated by means of RPA for the
instantaneous shapes, the probability of which is obtained by means of IBA.
Very good agreement with the experimental absorption cross sections near the
nucleon emission threshold is obtained.


title: Communication-optimal parallel and sequential QR and LU factorizations

abstract:
  We present parallel and sequential dense QR factorization algorithms that are
both optimal (up to polylogarithmic factors) in the amount of communication
they perform, and just as stable as Householder QR.
  We prove optimality by extending known lower bounds on communication
bandwidth for sequential and parallel matrix multiplication to provide latency
lower bounds, and show these bounds apply to the LU and QR decompositions. We
not only show that our QR algorithms attain these lower bounds (up to
polylogarithmic factors), but that existing LAPACK and ScaLAPACK algorithms
perform asymptotically more communication. We also point out recent LU
algorithms in the literature that attain at least some of these lower bounds.


title: Rapidity divergences and valid definitions of parton densities

abstract:
  Rapidity divergences occur when parton densities in a gauge theory are
defined in the most natural way, as expectation values of partonic number
operators in light-front quantization. I review these and other related
divergences, and show how the definitions of parton densities can be modified
to remove the divergences. A modified definition is not only essential for many
phenomenological applications of QCD, but also concerns the treatment of parton
densities in non-perturbative approaches. The necessity of modifications in the
definition of a parton density also entails corrections in the formulation of
light-front quantization for gauge theories.


title: Impact of Vehicular Communications Security on Transportation Safety

abstract:
  Transportation safety, one of the main driving forces of the development of
vehicular communication (VC) systems, relies on high-rate safety messaging
(beaconing). At the same time, there is consensus among authorities, industry,
and academia on the need to secure VC systems. With specific proposals in the
literature, a critical question must be answered: can secure VC systems be
practical and satisfy the requirements of safety applications, in spite of the
significant communication and processing overhead and other restrictions
security and privacy-enhancing mechanisms impose? To answer this question, we
investigate in this paper the following three dimensions for secure and
privacy-enhancing VC schemes: the reliability of communication, the processing
overhead at each node, and the impact on a safety application. The results
indicate that with the appropriate system design, including sufficiently high
processing power, applications enabled by secure VC can be in practice as
effective as those enabled by unsecured VC.


title:
The Acceleration of the Nebular Shells in Planetary Nebulae in the Milky
  Way Bulge

abstract:
  We present a systematic study of line widths in the [\ion{O}{3}]$\lambda$5007
and H$\alpha$ lines for a sample of 86 planetary nebulae in the Milky Way bulge
based upon spectroscopy obtained at the \facility{Observatorio Astron\'omico
Nacional in the Sierra San Pedro M\'artir (OAN-SPM)} using the Manchester
Echelle Spectrograph. The planetary nebulae were selected with the intention of
simulating samples of bright extragalactic planetary nebulae. We separate the
planetary nebulae into two samples containing cooler and hotter central stars,
defined by the absence or presence, respectively, of the \ion{He}{2}
$\lambda$6560 line in the H$\alpha$ spectra. This division separates samples of
younger and more evolved planetary nebulae. The sample of planetary nebulae
with hotter central stars has systematically larger line widths, larger radii,
lower electron densities, and lower H$\beta$ luminosities. The distributions of
these parameters in the two samples all differ at significance levels exceeding
99%. These differences are all in agreement with the expectations from
hydrodynamical models, but for the first time confirmed for a homogeneous and
statistically significant sample of galactic planetary nebulae. We interpret
these differences as evidence for the acceleration of the nebular shells during
the early evolution of these intrinsically bright planetary nebulae. As is the
case for planetary nebulae in the Magellanic Clouds, the acceleration of the
nebular shells appears to be the direct result of the evolution of the central
stars.


title:
Secure Neighbor Discovery in Wireless Networks: Formal Investigation of
  Possibility

abstract:
  Wireless communication enables a broad spectrum of applications, ranging from
commodity to tactical systems. Neighbor discovery (ND), that is, determining
which devices are within direct radio communication, is a building block of
network protocols and applications, and its vulnerability can severely
compromise their functionalities. A number of proposals to secure ND have been
published, but none have analyzed the problem formally. In this paper, we
contribute such an analysis: We build a formal model capturing salient
characteristics of wireless systems, most notably obstacles and interference,
and we provide a specification of a basic variant of the ND problem. Then, we
derive an impossibility result for a general class of protocols we term
"time-based protocols," to which many of the schemes in the literature belong.
We also identify the conditions under which the impossibility result is lifted.
Moreover, we explore a second class of protocols we term "time- and
location-based protocols," and prove they can secure ND.


title: Closed Timelike Curves Make Quantum and Classical Computing Equivalent

abstract:
  While closed timelike curves (CTCs) are not known to exist, studying their
consequences has led to nontrivial insights in general relativity, quantum
information, and other areas. In this paper we show that if CTCs existed, then
quantum computers would be no more powerful than classical computers: both
would have the (extremely large) power of the complexity class PSPACE,
consisting of all problems solvable by a conventional computer using a
polynomial amount of memory. This solves an open problem proposed by one of us
in 2005, and gives an essentially complete understanding of computational
complexity in the presence of CTCs. Following the work of Deutsch, we treat a
CTC as simply a region of spacetime where a "causal consistency" condition is
imposed, meaning that Nature has to produce a (probabilistic or quantum)
fixed-point of some evolution operator. Our conclusion is then a consequence of
the following theorem: given any quantum circuit (not necessarily unitary), a
fixed-point of the circuit can be (implicitly) computed in polynomial space.
This theorem might have independent applications in quantum information.


title: Solving the apparent diversity-accuracy dilemma of recommender systems

abstract:
  Recommender systems use data on past user preferences to predict possible
future likes and interests. A key challenge is that while the most useful
individual recommendations are to be found among diverse niche objects, the
most reliably accurate results are obtained by methods that recommend objects
based on user or object similarity. In this paper we introduce a new algorithm
specifically to address the challenge of diversity and show how it can be used
to resolve this apparent dilemma when combined in an elegant hybrid with an
accuracy-focused algorithm. By tuning the hybrid appropriately we are able to
obtain, without relying on any semantic or context-specific information,
simultaneous gains in both accuracy and diversity of recommendations.


title: Are There Meteors Originated from Near Earth Asteroid (25143) Itokawa?

abstract:
  As a result of a survey of Itokawid meteors (i.e., meteors originated from
Near Earth Asteroid (25143) Itokawa = 1998SF36), from among the multi-station
optical meteor orbit data of ~15000 orbits, and applying the D-criteria, we
could find five Itokawid meteor candidates. We also analyzed corresponding
mineral materials of the Itokawid candidates through their trajectory and
atmospheric data. We conclude, on the basis of our investigation, that the
fireball, MORP172, is the strongest Itokawid candidate.


title: Conformal dimension: Cantor sets and moduli

abstract:
  In this paper we give several conditions for a space to be minimal for
conformal dimension. We show that there are sets of zero length and conformal
dimension 1 thus answering a question of Bishop and Tyson. Another sufficient
condition for minimality is given in terms of a modulus of a system of measures
in the sense of Fuglede \cite{Fug}. It implies in particular that there are
many sets $E\subset\mathbb{R}$ of zero length such that $X\times Y$ is minimal
for conformal dimension for every compact $Y$.


title: Preferred-Frame and CP-Violation Tests with Polarized Electrons

abstract:
  We used a torsion pendulum containing $\approx 10^{23}$ polarized electrons
to search new interactions that couple to electron spin. We limit CP-violating
interactions between the pendulum's electrons and unpolarized matter in the
earth or the sun, test for rotation and boost-dependent preferred-frame effects
using the earth's rotation and velocity with respect to the entire cosmos, and
search for exotic velocity-dependent potentials between polarized electrons and
unpolarized matter in the sun and moon. Finally, we find that the gravitational
mass of an electron spinning toward the galactic center differs by less than
about 1 part in $10^{21}$ from an electron spinning in the opposite direction.
As a byproduct of this work, the density of polarized electrons in Sm$ $Co$_5$
was measured to be $(4.19\pm 0.19)\times 10^{22} {\rm cm}^{-3}$ at a field of
9.6 kG.


title: Fast and simple characterization of a photon pair source

abstract:
  We present an exact model of the detection statistics of a probabilistic
source of photon pairs from which a fast, simple and precise method to measure
the source's brightness and photon channel transmissions is demonstrated. We
measure such properties for a source based on spontaneous parametric
downconversion in a periodically poled LiNbO$_3$ crystal producing pairs at 810
and 1550 nm wavelengths. We further validate the model by comparing the
predicted and measured values for the $g^{(2)}(0)$ of a heralded single photon
source over a wide range of the brightness. Our model is of particular use for
monitoring and tuning the brightness on demand as required for various quantum
communication applications. We comment on its applicability to sources
involving spectral and/or spatial filtering.


title: Low-temperature magnetic ordering in SrEr$_2$O$_4$

abstract:
  SrEr$_2$O$_4$ has been characterised by low-temperature powder neutron
diffraction, as well as single crystal specific heat and magnetisation
measurements. Magnetisation measurements show that the magnetic system is
highly anisotropic at temperature above ordering. A magnetic field of 280 kOe
applied at $T=1.6$ K does not overcome the anisotropic magnetisation and fails
to fully saturate the system. Long range antiferromagnetic ordering develops
below $T_N=0.75$ K, identified by magnetic Bragg reflections with propagation
vector ${\bf k}=0$ and a lambda anomaly in the specific heat. The magnetic
structure consists of ferromagnetic chains running along the \textit{c} axis,
two adjacent chains being stacked antiferromagnetically. The moments point
along the \textit{c} direction, but only one of the two crystallographically
in-equivalent Er sites has a sizeable ordered magnetic moment, 4.5 $\rm \mu_B$
at 0.55 K. The magnetic properties of SrEr$_2$O$_4$ are discussed in terms of
the interplay between the low-dimensionality, competing exchange interactions,
dipolar interactions and low lying crystal field levels.


title: Efficient and Robust Secure Aggregation for Sensor Networks

abstract:
  Wireless Sensor Networks (WSNs) rely on in-network aggregation for
efficiency, however, this comes at a price: A single adversary can severely
influence the outcome by contributing an arbitrary partial aggregate value.
Secure in-network aggregation can detect such manipulation. But as long as such
faults persist, no aggregation result can be obtained. In contrast, the
collection of individual sensor node values is robust and solves the problem of
availability, yet in an inefficient way. Our work seeks to bridge this gap in
secure data collection: We propose a system that enhances availability with an
efficiency close to that of in-network aggregation. To achieve this, our scheme
relies on costly operations to localize and exclude nodes that manipulate the
aggregation, but \emph{only} when a failure is detected. The detection of
aggregation disruptions and the removal of faulty nodes provides robustness. At
the same time, after removing faulty nodes, the WSN can enjoy low cost (secure)
aggregation. Thus, the high exclusion cost is amortized, and efficiency
increases.


title:
The Intrinsic Difficulties of Constructing Strongly Correlated States of
  Lattice Quantum Gases by Connecting Up Pre-engineered Isolated Atomic
  Clusters

abstract:
  Suppose one engineers an artificial antiferromagnet on an array of {\em
isolated} wells, and then increases the tunneling between wells slowly, will
the system finally become an {\em equilibrium} antiferromagnet? Here, we show
that due to the intrinsic non-adiabaticity at the start of this process, and
that the atoms in the initial state in different wells are completely
uncorrelated, the final equilibrium state will have a temperature $T_{f}$ far
above the Neel temperature. Constructing other strongly correlated states (with
characteristic energy per particle $E^{\ast}$ comparable to the hopping or the
virtual hopping scale) with the same method will suffer the same problem, i.e.
$T_{f}>>E^{\ast}$.


abstract:
  We show that, for pertinent values of the fabrication and control parameters,
an attractive finite coupling fixed point emerges in the phase diagram of a
Y-junction of superconducting Josephson chains. The new fixed point arises only
when the dimensionless flux $f$ piercing the central loop of the network equals
$\pi$ and, thus, does not break time-reversal invariance; for $f \neq \pi$,
only the strongly coupled fixed point survives as a stable attractive fixed
point. Phase slips (instantons) have a crucial role in establishing this
transition: we show indeed that, at
  $f = \pi$, a new set of instantons -the W-instantons- comes into play to
destabilize the strongly coupled fixed point.
  Finally, we provide a detailed account of the Josephson current-phase
relationship along the arms of the network, near each one of the allowed fixed
points. Our results evidence remarkable similarities between the phase diagram
accessible to a Y-junction of superconducting Josephson chains and the one
found in the analysis of quantum Brownian motion on frustrated planar lattices.


title: Integer Points in Backward Orbits

abstract:
  A theorem of J. Silverman states that a forward orbit of a rational map
$\phi(z)$ on $\mathbb P^1(K)$ contains finitely many $S$-integers in the number
field $K$ when $(\phi\circ\phi)(z)$ is not a polynomial. We state an analogous
conjecture for the backward orbits using a general $S$-integrality notion based
on the Galois conjugates of points. This conjecture is proven for the map
$\phi(z)=z^d$, and consequently Chebyshev polynomials, by uniformly bounding
the number of Galois orbits for $z^n-\beta$ when $\beta\not =0$ is a non-root
of unity. In general, our conjecture is true provided that the number of Galois
orbits for $\phi^n(z)-\beta$ is bounded independently of $n$.


title: Optimal control of a leaking qubit

abstract:
  Physical implementations of quantum bits can contain coherent transitions to
energetically close non-qubit states. In particular, for anharmonic oscillator
systems such as the superconducting phase qubit and the transmon a two-level
approximation is insufficient. We apply optimal control theory to the envelope
of a resonant Rabi pulse in a qubit in the presence of a single, weakly
off-resonant leakage level. The gate error of a spin flip operation reduces by
orders of magnitude compared to simple pulse shapes. Near-perfect gates can be
achieved for any pulse duration longer than an intrinsic limit given by the
nonlinearity. The pulses can be understood as composite sequences that refocus
the leakage transition. We also discuss ways to improve the pulse shapes.


title:
Quantum properties of a superposition of squeezed displaced two-mode
  vacuum and single-photon states

abstract:
  In this paper, we study some quantum properties of a superposition of
displaced squeezed two-mode vacuum and single-photon states, such as the
second-order correlation function, the Cauchy-Schwartz inequality, quadrature
squeezing, quasiprobability distribution functions and purity. This type of
states includes two mechanisms, namely, interference in phase space and
entanglement. We show that these states can exhibit sub-Piossonian statistics,
squeezing and deviate from the classical Cauchy-Schwartz inequality. Moreover,
the amount of entanglement in the system can be increased by increasing the
squeezing mechanism. In the framework of the quasiprobability distribution
functions we show that the single-mode state can tend to thermal state based on
the correlation mechanism. Generation scheme for such states is given.


title:
From force distribution to average coordination number in frictional
  granular matter

abstract:
  We study the joint probability distribution of normal and tangential
frictional forces in jammed granular media, $P_{\mu}(f_t, f_n)$, for various
friction coefficient $\mu$, especially when $\mu = \infty$. A universal scaling
law is found to collapse the data for $\mu=0$ to $\infty$ demonstrating a link
between force distribution $P_{\mu}(f_t, f_n)$ and average coordination number,
$z^{\mu}_c$. The results determine $z_c^\mu$ for a finite friction coefficient,
extending the constraints counting argument of isostatic granular packing to
finite frictional packings.


title: Study a0(980)-f0(980) mixing from a0(980) -> f0(980) transition

abstract:
  Various processes have been proposed previously to study a0(980)-f0(980)
mixing through f0(980)->a0(980) transition. Here we investigate in detail the
difference between a0(980)->f0(980) and f0(980)->a0(980) transitions. It is
found that the a0(980)->f0(980) transition can provide additional constrains to
the parameters of a0(980) and f0(980) mesons. Proposal is made to study
a0(980)-f0(980) mixing from chi_{c1}->pi^0 a0(980) -> pi^0 f0(980) reaction at
the upgraded Beijing electron positron collider with the BESIII detector.


title: Hydrodynamics and Flow

abstract:
  In this lecture note, we present several topics on relativistic hydrodynamics
and its application to relativistic heavy ion collisions. In the first part we
give a brief introduction to relativistic hydrodynamics in the context of heavy
ion collisions. In the second part we present the formalism and some
fundamental aspects of relativistic ideal and viscous hydrodynamics. In the
third part, we start with some basic checks of the fundamental observables
followed by discussion of collective flow, in particular elliptic flow, which
is one of the most exciting phenomenon in heavy ion collisions at relativistic
energies. Next we discuss how to formulate the hydrodynamic model to describe
dynamics of heavy ion collisions. Finally, we conclude the third part of the
lecture note by showing some results from ideal hydrodynamic calculations and
by comparing them with the experimental data.


title: Statistical Tools for Analyzing the Cosmic Ray Energy Spectrum

abstract:
  In this paper un-binned statistical tools for analyzing the cosmic ray energy
spectrum are developed and illustrated with a simulated data set. The methods
are designed to extract accurate and precise model parameter estimators in the
presence of statistical and systematic energy errors. Two robust methods are
used to test for the presence of flux suppression at the highest energies: the
Tail-Power statistic and a likelihood ratio test. Both tests give evidence of
flux suppression in the simulated data. The tools presented can be generalized
for use on any astrophysical data set where the power-law assumption is
relevant and can be used to aid observational design.


title: Discretely ordered groups

abstract:
  We consider group orders and right-orders which are discrete, meaning there
is a least element which is greater than the identity. We note that free groups
cannot be given discrete orders, although they do have right-orders which are
discrete. More generally, we give necessary and sufficient conditions that a
given orderable group can be endowed with a discrete order. In particular,
every orderable group G embeds in a discretely orderable group. We also
consider conditions on right-orderable groups to be discretely right-orderable.
Finally, we discuss a number of illustrative examples involving discrete
orderability, including the Artin braid groups and Bergman's
non-locally-indicable right orderable groups.


title: Quantum Memory with Optically Trapped Atoms

abstract:
  We report the experimental demonstration of a quantum memory for collective
atomic states in a far-detuned optical dipole trap. Generation of the
collective atomic state is heralded by the detection of a Raman scattered
photon and accompanied by storage in the ensemble of atoms. The optical dipole
trap provides confinement for the atoms during the quantum storage while
retaining the atomic coherence. We probe the quantum storage by
cross-correlation of the photon pair arising from the Raman scattering and the
retrieval of the atomic state stored in the memory. Non-classical correlations
are observed for storage times up to 60 microseconds.


title:
A simple estimation of the maximal rank of tensors with two slices by
  row and column operations, symmetrization and induction

abstract:
  The determination of the maximal ranks of a set of a given type of tensors is
a basic problem both in theory and application. In statistical applications,
the maximal rank is related to the number of necessary parameters to be built
in a tensor model. Based on this classical theorem by Bosch we will show the
tight bound for 2 x n x n tensors by simple row and column operations,
symmetrization and mathematical induction, which has been given by several
authors based on eigenvalue theories.


title:
On the dangers of using the growth equation on large scales in the
  Newtonian gauge

abstract:
  We examine the accuracy of the growth equation $\ddot{\delta} +
2H\dot{\delta} - 4\pi G\rho\delta = 0$, which is ubiquitous in the cosmological
literature, in the context of the Newtonian gauge. By comparing the growth
predicted by this equation to a numerical solution of the linearized Einstein
equations in the $\Lambda$CDM scenario, we show that while this equation is a
reliable approximation on small scales ($k\gtrsim $h Mpc$^{-1}$), it can be
disastrously inaccurate ($\sim 10^4% $) on larger scales in this gauge. We
propose a modified version of the growth equation for the Newtonian gauge,
which while preserving the simplicity of the original equation, provides
considerably more accurate results. We examine the implications of the failure
of the growth equation on a few recent studies, aimed at discriminating general
relativity from modified gravity, which use this equation as a starting point.
We show that while the results of these studies are valid on small scales, they
are not reliable on large scales or high redshifts, if one works in the
Newtonian gauge. Finally, we discuss the growth equation in the synchronous
gauge and show that the corrections to the Poisson equation are exactly
equivalent to the difference between the overdensities in the synchronous and
Newtonian gauges.


title: Complex manifolds with generating tangent bundles

abstract:
  Let $M$ be a close complex manifold and $TM$ its holomorphic tangent bundle.
We prove that if the global holomorphic sections of tangent bundle generate
each fibre, then $M$ is a complex homogeneous manifold.
  Our proof depends on the complex version of Chow-Rashevskii theorem in
Carnot-Caratheodory spaces.


title: Fuzzy Ring from M2-brane Giant Torus

abstract:
  We construct spinning dual M2 giant gravitons in AdS_4 x S^7, which
generically become 1/16 BPS states, and show that their world-volumes become
torii. By taking an orbifold, we obtain spinning dielectric D2-brane
configurations in AdS_4 x CP^3 dual to specific BPS operators in ABJM theory.
This reveals a novel mechanism how to give an angular momentum to a dielectric
D2-brane. We also find that when its angular momentum in the AdS_4 becomes
large, it approaches to a ring-like object. Our result might suggest an
existence of supersymmetric black rings in the AdS_4 background. We will also
discuss dual giant gravitons in AdS_4 x CP^3.


title: A dozen integrals: Russell-style

abstract:
  On June 15, 1876, the Proceedings of the Royal Society of London published a
paper by Mr. W. H. L. Russell entitled "On certain integrals". The paper starts
with "The following are certain integrals which will, I hope, be found
interesting". The rest of the paper is simply a list of 12 integrals. We
provide a list of 12 integrals that we hope would be interesting.


title: AKARI/FIS Mapping of the ISM-Wind Bow Shock around Alpha Ori

abstract:
  We present 10' x 50' scan maps around an M supergiant Alpha Ori at 65, 90,
140 and 160 microns obtained with the AKARI Infrared Astronomy Satellite.
Higher spatial resolution data with the exact analytic solution permit us to
fit the de-projected shape of the stellar wind bow shock around Alpha Ori to
have the stand-off distance of 4.8', position angle of 55 degrees and
inclination angle of 56 degrees. The shape of the bow shock suggests that the
peculiar velocity of Alpha Ori with respect to the local medium is v_* = 40
(n_H)^(-1/2), where n_H is the hydrogen nucleus density at Alpha Ori. We find
that the local medium is of n_H = 1.5 to 1.9 cm^(-3) and the velocity of the
local flow is at 11 km s^(-1) by using the most recent astrometric solutions
for Alpha Ori under the assumption that the local medium is moving away from
the Orion OB 1 association. AKARI images may also reveal a vortex ring due to
instabilities on the surface of the bow shock as demonstrated by numerical
models. This research exemplifies the potential of AKARI All-Sky data as well
as follow-up observations with Herschel Space Telescope and Stratospheric
Observatory for Infrared Astronomy for this avenue of research in revealing the
nature of interaction between the stellar wind and interstellar medium.


title:
Mutual information and swap operation in the two-qubit Heisenberg model
  with Dzyaloshinskii-Moriya anisotropic antisymmetric interaction

abstract:
  Mutual information and swap operation in the two-qubit Heisenberg model with
the Dzyaloshinskii-Moriya (DM) anisotropic antisymmetric interaction are
investigated. It is found that the mutual information I of such a quantum
channel is sensitive to the initial conditions and declines with the increase
of the temperature. The DM interaction can lead to a higher mutual information,
especially for the ferromagnetic case. The entanglement quality of input states
cannot enhance the mutual information of the quantum channel. When the DM
interaction is large, the mutual information will be the maximum value 2 for a
non-entangled input state, but it is 1 for a maximally entangled input one. It
is also shown that the swap operation can be implemented for some kinds of DM
coupling. The conditions of the DM coupling under which the swap operation is
feasible are established.


title:
Resistivity saturation in PrFeAsO$_{1-x}$F$_y$ superconductor: An
  evidence of strong electron-phonon coupling

abstract:
  We have measured the resistivity of PrFeAsO$_{1-x}$F$_y$ samples over a wide
range of temperature in order to elucidate the role of electron-phonon
interaction on normal- and superconducting-state properties. The linear T
dependence of $\rho$ above 170 K followed by a saturationlike behavior at
higher temperature is a clear signature of strong electron-phonon coupling.
  From the analysis of T dependence of $\rho$, we have estimated several
normal-state parameters useful for understanding the origin of
superconductivity in this system. Our results suggest that Fe-based
oxypnictides are phonon mediated BCS superconductors like Chevrel phases and
A15 compounds.


title:
Time-delay interferometry and the relativistic treatment of LISA optical
  links

abstract:
  LISA is a joint space mission of the ESA and NASA for detecting low frequency
gravitational radiation in the band $10^{-5} - 1$ Hz. In order to attain the
requisite sensitivity for LISA, the laser frequency noise must be suppressed
below the other secondary noises such as the optical path noise, acceleration
noise etc. This is achieved because of the redundancy in the data, more
specifically, by combining six appropriately time-delayed data streams
containing fractional Doppler shifts - time delay interferometry (TDI). The
orbits of the spacecraft are computed in the gravitational field of the Sun and
Earth in the Newtonian framework, while the optical links are treated fully
general relativistically and thus, effects such as the Sagnac, Shapiro delay,
etc. are automatically incorporated. We show that in the model of LISA that we
consider here, there are symmetries inherent in the physics, which may be used
effectively to suppress the residual laser frequency noise and simplify the
algebraic approach to TDI.


title:
Adiabatic approximation with exponential accuracy for many-body systems
  and quantum computation

abstract:
  We derive a version of the adiabatic theorem that is especially suited for
applications in adiabatic quantum computation, where it is reasonable to assume
that the adiabatic interpolation between the initial and final Hamiltonians is
controllable. Assuming that the Hamiltonian is analytic in a finite strip
around the real time axis, that some number of its time-derivatives vanish at
the initial and final times, and that the target adiabatic eigenstate is
non-degenerate and separated by a gap from the rest of the spectrum, we show
that one can obtain an error between the final adiabatic eigenstate and the
actual time-evolved state which is exponentially small in the evolution time,
where this time itself scales as the square of the norm of the time-derivative
of the Hamiltonian, divided by the cube of the minimal gap.


title:
A construction of Frobenius manifolds with logarithmic poles and
  applications

abstract:
  A construction theorem for Frobenius manifolds with logarithmic poles is
established. This is a generalization of a theorem of Hertling and Manin. As an
application we prove a generalization of the reconstruction theorem of
Kontsevich and Manin for projective smooth varieties with convergent
Gromov-Witten potential. A second application is a construction of Frobenius
manifolds out of a variation of polarized Hodge structures which degenerates
along a normal crossing divisor when certain generation conditions are
fulfilled.


title:
Dissociation of quarkonium in hot QCD medium: Modification of the
  inter-quark potential

abstract:
  We have studied the dissociation of heavy quarkonium states in a hot QCD
medium by investigating the medium modifications to a heavy quark potential.
Our model shows that in-medium modification causes the screening of the charge
in contrast to the screening of the range of the potential. We have then
employed the medium-modified potential to estimate the dissociation pattern of
the charmonium and bottomonium states and also explore how the pattern changes
as we go from the perturbative to nonperturbative domain in the Debye mass. The
results are in good agreement with the other current theoretical works both
from the spectral function analysis and the potential model study.