title: Outside-in disk evolution in the LMC

abstract:
  From the analysis of the color-magnitude diagrams and color functions of four
wide LMC fields located from ~2 to 6 kpc from the kinematic center of the LMC
we present evidence that, while the oldest population is coeval in all fields,
the age of the youngest component of the dominant stellar population gradually
increases with galactocentric distance, from currently active star formation in
a field at 2.3 deg, to 100 Myr, 0.8 Gyr, and 1.5 Gyr in fields at 4.0 deg, 5.5
deg, and 7.1 deg, respectively. This outside-in quenching of the star formation
in the LMC disk is correlated with the decreasing HI column density (which is <
2x 10^{20} cm^{-2} in the two outermost fields with little or no current star
formation. Other work in the literature hints at similar behavior in the
stellar populations of irregular galaxies, and in M33. This is observational
evidence against the inside-out disk formation scenario in low-mass spirals and
irregular galaxies. Alternatively, it could be that the age distribution with
radius results from interplay between the evolution with time of the
star-forming area of the LMC and the subsequent outward migration of the stars.


title:
X-ray observations of the Large Magellanic Cloud pulsar PSR B0540-69 and
  its PWN

abstract:
  PSR B0540-69 is a young pulsar in the Large Magellanic Cloud that has similar
properties with respect to the Crab Pulsar, and is embedded in a Pulsar Wind
Nebula. We have analyzed the complete archival RXTE dataset of observations of
this source, together with new Swift-XRT and INTEGRAL-IBIS data. Accurate
lightcurves are produced in various energy bands between 2 and 60 keV, showing
no significant energy variations of the pulse shape. The spectral analysis
shows that the pulsed spectrum is curved, and is best fitted up to 100 keV by a
log-parabolic model: this strengthens the similarities with the Crab pulsar,
and is discussed in the light of a phenomenologic multicomponent model. The
total emission from this source is studied, the relative contributions of the
pulsar and the PWN emission are derived, and discussed in the context of other
INTEGRAL detected pulsar/PWN systems.


title:
The physics of space and time III: Classification of space-time
  experiments and the twin paradox

abstract:
  A nomenclature for inertial frames and a notation for space and time
coordinates is proposed to give an unambigous description of space-time
experiments in special relativity. Of particular importance are the concepts of
`base' and `travelling' frames and `primary' and `reciprocal' experiments. A
detailed discussion of the twin paradox is presented. The physical basis of the
differential aging effect is found to be a relativistic relative-velocity
transformation relation, not, as hitherto supposed, the spurious `length
contraction' effect.


title:
Radiative correction to the lightest neutral Higgs mass in warped
  supersymmetry

abstract:
  We compute radiative correction to the lightest neutral Higgs mass ($m_h$)
induced by the Kaluza-Klein (KK) towers of fermions and sfermions in a minimal
supersymmetric scenario embeded in a 5-dimensional warped space. The Higgs is
confined to the TeV brane. The KK spectra of matter supermultiplets is tied to
the explanation of the fermion mass hierarchy problem. We demonstrate that for
a reasonable choice of extra-dimensional parameters, the KK-induced radiative
correction can enhance the upper limit on $m_h$ by as much as 100 GeV beyond
the 4d limit of 135 GeV.


title:
Some new implications of the anomalous baryon current in the Standard
  Model

abstract:
  Phenomenological implications of the anomalous baryon current in the Standard
Model are discussed, in particular neutrino-photon interactions at finite
baryon density. A pedagogical derivation of the baryon current anomaly is
given.


title: Consequences of T-parity breaking in the Littlest Higgs model

abstract:
  In this paper we consider the effects of the T-parity violating anomalous
Wess-Zumino-Witten-Term in the Littlest Higgs model. Apart from tree level
processes, the loop induced decays of the heavy mirror particles into light
standard model fermions lead to a new and rich phenomenology in particular at
breaking scales f below 1 TeV. Various processes are calculated and their
signatures at present and future colliders are discussed. As a byproduct we
find an alternative production mechanism for the Higgs boson.


title:
Integrable Structure of $5d$ $\mathcal{N}=1$ Supersymmetric Yang-Mills
  and Melting Crystal

abstract:
  We study loop operators of $5d$ $\mathcal{N}=1$ SYM in $\Omega$ background.
For the case of U(1) theory, the generating function of correlation functions
of the loop operators reproduces the partition function of melting crystal
model with external potential. We argue the common integrable structure of $5d$
$\mathcal{N}=1$ SYM and melting crystal model.


title: Inverse zero-sum problems and algebraic invariants

abstract:
  In this article, we study the maximal cross number of long zero-sumfree
sequences in a finite Abelian group. Regarding this inverse-type problem, we
formulate a general conjecture and prove, among other results, that this
conjecture holds true for finite cyclic groups, finite Abelian p-groups and for
finite Abelian groups of rank two. Also, the results obtained here enable us to
improve, via the resolution of a linear integer program, a result of W. Gao and
A. Geroldinger concerning the minimal number of elements with maximal order in
a long zero-sumfree sequence of a finite Abelian group of rank two.


title: Two solvable systems of coagulation equations with limited aggregations

abstract:
  We consider two simple models for the formation of polymers where at the
initial time, each monomer has a certain number of potential links (called arms
in the text) that are consumed when aggregations occur. Loosely speaking, this
imposes restrictions on the number of aggregations. The dynamics of
concentrations are governed by modifications of Smoluchowski's coagulation
equations. Applying classical techniques based on generating functions,
resolution of quasi-linear PDE's, and Lagrange inversion formula, we obtain
explicit solutions to these non-linear systems of ODE's. We also discuss the
asymptotic behavior of the solutions and point at some connexions with certain
known solutions to Smoluchowski's coagulation equations with additive or
multiplicative kernels.


title: A look at the influence of the $J/\psi$ transverse momentum on shadowing

abstract:
  Stringent physical constraints relate the $J/\psi$ produced at a given
transverse momentum $p_T$ to the Bjorken-$x$ of the initial gluons. We present
a new approach which takes them into account in order to explicitely
investigate the $p_T$-dependence of the shadowing effect on the $J/\psi$
production. Using the $J/\psi$ rapidity and $p_T$ spectra extracted from
$\sqrt{s}=200\mathrm{GeV}$ p + p data from PHENIX, we build a Glauber
Monte-Carlo code which includes shadowing in two alternative ways: multiple
scattering corrections or $Q^2$ evolution of parton densities. We present our
results in d + Au collisions at the same energy, notably providing the first
prediction of the $J/\psi$ nuclear modification factor as a function of $p_T$,
and compare them to the available data by adding some nuclear absorption
effect.


title:
Phenomenological Lagrangian approach to the electromagnetic deuteron
  form factors

abstract:
  A phenomenological Lagrangian approach is employed to study the
electromagnetic properties of the deuteron. The deuteron is regarded as a
weakly bound state of the proton and neutron. We construct a general form for
the electromagnetic one- and two-body transition operators formulated in terms
of the nucleon fields, which are then used in the calculation of the
electromagnetic deuteron form factors. One of the two-body operators is
responsible for explaining the quadrupole moment form factor. We show that in
our approach the data on the deuteron form factors as well as on the
differential cross section of elastic electron-deuteron scattering are well
explained.


title: The Slice Algorithm For Irreducible Decomposition of Monomial Ideals

abstract:
  Irreducible decomposition of monomial ideals has an increasing number of
applications from biology to pure math. This paper presents the Slice Algorithm
for computing irreducible decompositions, Alexander duals and socles of
monomial ideals. The paper includes experiments showing good performance in
practice.


title: On the d-dimensional Quasi-Equally Spaced Sampling

abstract:
  We study a class of random matrices that appear in several communication and
signal processing applications, and whose asymptotic eigenvalue distribution is
closely related to the reconstruction error of an irregularly sampled
bandlimited signal. We focus on the case where the random variables
characterizing these matrices are d-dimensional vectors, independent, and
quasi-equally spaced, i.e., they have an arbitrary distribution and their
averages are vertices of a d-dimensional grid. Although a closed form
expression of the eigenvalue distribution is still unknown, under these
conditions we are able (i) to derive the distribution moments as the matrix
size grows to infinity, while its aspect ratio is kept constant, and (ii) to
show that the eigenvalue distribution tends to the Marcenko-Pastur law as
d->infinity. These results can find application in several fields, as an
example we show how they can be used for the estimation of the mean square
error provided by linear reconstruction techniques.


title:
Free quasi-symmetric functions and descent algebras for wreath products,
  and noncommutative multi-symmetric functions

abstract:
  We introduce analogs of the Hopf algebra of Free quasi-symmetric functions
with bases labelled by colored permutations. When the color set is a semigroup,
an internal product can be introduced. This leads to the construction of
generalized descent algebras associated with wreath products $\Gamma\wr\SG_n$
and to the corresponding generalizations of quasi-symmetric functions. The
associated Hopf algebras appear as natural analogs of McMahon's multisymmetric
functions. As a consequence, we obtain an internal product on ordinary
multi-symmetric functions. We extend these constructions to Hopf algebras of
colored parking functions, colored non-crossing partitions and parking
functions of type B.


title: On the total curvature of semialgebraic graphs

abstract:
  We define the total curvature of a semialgebraic embedding of a graph in the
3-dimensional Euclidean space. We prove that it satisfies a Chern-Lashof type
inequality and we describe when the equality holds. We also prove a
generalization of a classical result of Fary and Milnor stating that certain
graphs cannot be knotted if they are not too curved. The techniques employed
are Morse theoretic.


title:
Estimation of a diffusion model with trends taking in account the
  extremes. Application to temperature in France

abstract:
  We built a model of the daily temperature based on a diffusion process and
address to extreme values not taken into account in the literature on this kind
of models. We first study, using non parametric tools, the trends on mean and
variance. In a second step we estimate a stationary model first non
parametrically and then using likelihood methods. Extreme values are taken into
account in the estimation of model and to obtain a definitive estimation we use
in a specific framework extreme theory for diffusions. A test of suitable model
by simulation is done.


title:
Quantitative Theory of a Time-Correlation Function in a One-Component
  Glass-Forming Liquid with Anisotropic Potential

abstract:
  The Shintani-Tanaka model is a glass-forming system whose constituents
interact via anisotropic potential depending on the angle of a unit vector
carried by each particle. The decay of time-correlation functions of the unit
vectors exhibits the characteristics of generic relaxation functions during
glass transitions. In particular it exhibits a 'stretched exponential' form,
with the stretching index beta depending strongly on the temperature. We
construct a quantitative theory of this correlation function by analyzing all
the physical processes that contribute to it, separating a rotational from a
translational decay channel. Interestingly, the separate decay function of each
of these processes is temperature independent. Taken together with
temperature-dependent weights determined a-priori by statistical mechanics one
generates the observed correlation function in quantitative agreement with
simulations at different temperatures. This underlines the danger of concluding
anything about glassy relaxation functions without detailed physical scrutiny.


title:
A matrix interpolation between classical and free max operations: I. The
  univariate case

abstract:
  Recently, Ben Arous and Voiculescu considered taking the maximum of two free
random variables and brought to light a deep analogy with the operation of
taking the maximum of two independent random variables. We present here a new
insight on this analogy: its concrete realization based on random matrices
giving an interpolation between classical and free settings.


title: Quantum Group of Orientation preserving Riemannian Isometries

abstract:
  We formulate a quantum group analogue of the group of orinetation-preserving
Riemannian isometries of a compact Riemannian spin manifold, more generally, of
a (possibly $R$-twisted in the sense of a paper of one of the authors, and of
compact type) spectral triple. The main advantage of this formulation, which is
directly in terms of the Dirac operator, is that it does not need the existence
of any `good ' Laplacian as in our previous works on quantum isometry groups.
Several interesting examples, including those coming from Rieffel-type
deformation as well as the equivariant spectral triples on $SU_\mu(2)$ and
$S^2_{\mu 0}$ are dicussed.


title: A young, dusty, compact radio source within a Ly|*alpha*| halo

abstract:
  We report here on the discovery of a red quasar, J004929.4+351025.7 at a
redshift of z = 2.48, situated within a large Lya emission-line halo. The radio
spectral energy distribution implies that the radio jets were triggered < 10^4
years prior to the time at which the object is observed, suggesting that the
jet triggering of the active galactic nucleus is recent. The loosely biconical
structure of the emission-line halo suggests that it is ionised by photons
emitted by the central quasar nucleus and that the central nucleus is obscured
by a dusty torus with Av ~ 3.0. The large spatial extent of the Lya halo
relative to the radio emission means this could only have occurred if the radio
jets emerged from an already established highly-accreting black hole. This
suggests that the radio-jet triggering is delayed with respect to the onset of
accretion activity on to the central supermassive black hole.


title:
Constraints on the Dark Matter Annihilations by Neutrinos with
  Substructure Effects Included

abstract:
  Dark matter (DM) annihilations in the Galaxy may produce high energy
neutrinos, which can be detected by the neutrino telescopes, for example
IceCube, ANTARES and Super-Kamiokande. The neutrinos can also arise from
hadronic interaction between cosmic ray and atmosphere around the Earth, known
as atmospheric neutrino. Current measurements on neutrino flux is consistent
with theoretical prediction of atmospheric neutrino within the uncertainties.
In this paper, by requiring that the DM annihilation neutrino flux is less than
the current measurements, we obtain an upper bound on the cross section of dark
matter annihilation $ < {\sigma v} >$. Compared with previous investigations,
we improve the bound by including DM substructure contributions. In our paper,
two kinds of substructure effects are scrutinized. One is the substructure
average contribution over all directions. The other is point source effect by
single massive sub-halo. We found that the former can improve the bound by
several times, while the latter can improve the bound by $ 10^1 \sim 10^4$
utilizing the excellent angular resolution of neutrino telescope IceCube. The
exact improvement depends on the DM profile and the sub-halo concentration
model. In some model, IceCube can achieve the sensitivity of $ < {\sigma v} >
\sim 10^{- 26} cm^3 s^{- 1} $.


title: The long-range interaction in massless (lambda Phi^4)_4 theory

abstract:
  Does massless (lambda Phi^4)_4 theory exhibit spontaneous symmetry breaking
(SSB)? The raw 1-loop result implies that it does, but the "RG-improved" result
implies the opposite. I argue that the appropriate "low-energy effective
theory" is a nonlocal field theory involving an attractive, long-range
interaction Phi^2(x) Phi^2(y)/z^4, where z=|x-y|. RG improvement then requires
running couplings for both this interaction and the original pointlike
interaction. A crude calculation in this framework yields SSB even after "RG
improvement" and closely agrees with the raw 1-loop result.


title: Noncommutative independence from the braid group $B_\infty$

abstract:
  We introduce `braidability' as a new symmetry for (infinite) sequences of
noncommutative random variables related to representations of the braid group
$B_\infty$. It provides an extension of exchangeability which is tied to the
symmetric group $S_\infty$. Our key result is that braidability implies
spreadability and thus conditional independence, according to the
noncommutative extended de Finetti theorem (of C. K\"{o}stler). This endows the
braid groups $B_n$ with a new intrinsic (quantum) probabilistic interpretation.
We underline this interpretation by a braided extension of the Hewitt-Savage
Zero-One Law.
  Furthermore we use the concept of product representations of endomorphisms
(of R. Gohm) with respect to certain Galois type towers of fixed point algebras
to show that braidability produces triangular towers of commuting squares and
noncommutative Bernoulli shifts. As a specific case we study the left regular
representation of $B_\infty$ and the irreducible subfactor with infinite Jones
index in the non-hyperfinite $II_1$-factor $L(B_\infty)$ related to it. Our
investigations reveal a new presentation of the braid group $B_\infty$, the
`square root of free generator presentation' $F_\infty^{1/2}$. These new
generators give rise to braidability while the squares of them yield a free
family. Hence our results provide another facet of the strong connection
between subfactors and free probability theory and we speculate about
braidability as an extension of (amalgamated) freeness on the combinatorial
level.


title: Charged Condensate and Helium Dwarf Stars

abstract:
  White dwarf stars composed of carbon, oxygen or heavier elements are expected
to crystallize as they cool down below certain temperatures. Yet, simple
arguments suggest that the helium white dwarf cores may not solidify, mostly
because of zero-point oscillations of the helium ions that would dissolve the
crystalline structure. We argue that the interior of the helium dwarfs may
instead form a macroscopic quantum state in which the charged helium-4 nuclei
are in a Bose-Einstein condensate, while the relativistic electrons form a
neutralizing degenerate Fermi liquid. We discuss the electric charge screening,
and the spectrum of this substance, showing that the bosonic long-wavelength
fluctuations exhibit a mass gap. Hence, there is a suppression at low
temperatures of the boson contribution to the specific heat -- the latter being
dominated by the specific heat of the electrons near the Fermi surface. This
state of matter may have observational signatures.


title:
Gravitational lenses and lens candidates identified from the COSMOS
  field

abstract:
  A complete manual search has been carried out of the list of 285423 objects,
nearly all of them galaxies, identified in the COSMOS field that are brighter
than I=25. Two certain and one highly probable new gravitational lenses are
found, in addition to the lenses and candidate lens systems previously found by
Faure et al. (2008). A further list of 112 candidate lens systems is presented.
Few of these are likely to be true gravitational lens systems, most being
star-forming rings or pairs of companion galaxies. It is possible to examine of
order 10^6 objects by eye in a reasonable time, although reliable detection of
lenses by such methods is likely to be possible only with high-resolution data.
The loss of completeness involved in a rapid search is estimated as up to a
factor of 2, depending on the morphology of the lens candidate.


title:
Quasi-simultaneous multi-frequency observations of inverted-spectrum GPS
  candidate sources

abstract:
  Gigahertz-Peaked Spectrum (GPS) sources are probably the precursors of local
radio galaxies.Existing GPS source samples are small (<200). It is necessary to
extend the availabe sample of the Gigahertz-Peaked Spectrum (GPS) and High
Frequency Peaker (HFP) sources in order to study their nature with greater
details and higher statistical significance. A sample of 214 radio sources,
which were extracted from the SPECFIND catalog and show an inverted radio
spectrum, were observed quasi-simultaneously at 4.85, 10.45, and 32GHz with the
100-m Effelsberg radio telescope. Using the VLBA calibrator survey (VCS) we
have investigated the parsec-scale morphology of the sources. About 45% of the
sources in our sample are classified as GPS or HFP candidates. We add 65 new
GPS/HFP candidates to existing samples. We confirm the expected tendency that
HFP are more compact on milliarcsecond scale than the 'classical' GPS sources,
which peak at lower frequencies. The data mining of the SPECFIND database
represents a promising tool for the discovery of new GPS/HFP sources.


title: Duality of real and quaternionic random matrices

abstract:
  We show that quaternionic Gaussian random variables satisfy a generalization
of the Wick formula for computing the expected value of products in terms of a
family of graphical enumeration problems. When applied to the quaternionic
Wigner and Wishart families of random matrices the result gives the duality
between moments of these families and the corresponding real Wigner and Wishart
families.


title: On the distances between entangled pseudoscalar mesons states

abstract:
  Entangled states of pseudoscalar mesons represent a very interesting tool for
studying foundations of quantum mechanics, e.g. for testing Bell inequalities.
Recently, they also emerged as a test bench for quantum information protocols.
On the other hand, from a quantum information point of view, the
characterization of the distance between two quantum states is a topic of the
utmost importance. In this letter, with the purpose of providing a useful tool
for further investigations, we address the problem of which distance allows a
better discrimination between density matrices appearing in pseudoscalar
phenomenology.


title:
The Stellar Abundances for Galactic Archeology (SAGA) Database -
  Compilation of the Characteristics of Known Extremely Metal-Poor Stars

abstract:
  We describe the construction of a database of extremely metal-poor (EMP)
stars in the Galactic halo whose elemental abundances have been determined. Our
database contains detailed elemental abundances, reported equivalent widths,
atmospheric parameters, photometry, and binarity status, compiled from papers
in the recent literature that report studies of EMP halo stars with [Fe/H] <
-2.5. The compilation procedures for this database have been designed to
assemble the data effectively from electronic tables available from online
journals. We have also developed a data retrieval system that enables data
searches by various criteria, and permits the user to explore relationships
between the stored variables graphically. Currently, our sample includes 1212
unique stars (many of which are studied by more than one group) with more than
15000 individual reported elemental abundances, covering all of the relevant
papers published by December 2007. We discuss the global characteristics of the
present database, as revealed by the EMP stars observed to date. For stars with
[Fe/H] < -2.5, the number of giants with reported abundances is larger than
that of dwarfs by a factor of two. The fraction of carbon-rich stars (among the
sample for which the carbon abundance is reported) amount to ~30 % for [Fe/H] <
-2.5. We find that known binaries exhibit different distributions of orbital
period, according to whether they are giants or dwarfs, and also as a function
of metallicity, although the total sample of such stars is still quite small.


title: Scalar Meson Photoproduction

abstract:
  The light-quark non-strange scalar mesons a0(980), f0(980), f0(1370),
a0(1450), f0(1500) and f0(1710) are of great interest as there is no generally
accepted view of their structure which can encompass q-q-qbar-qbar, molecular,
q-qbar and glueball states in various combinations. It has been shown
previously that the radiative decays of the scalar mesons to rho and omega are
a good probe of their structure and provide good discrimination among models.
Scalar meson photoproduction is proposed as an alternative to measuring
radiative decays and it is shown that it is a feasible proposition.


title: A Realization of the Cohen-Glashow Very Special Relativity

abstract:
  We show that the Cohen-Glashow Very Special Relativity (VSR) theory [1] can
be realized as the part of the Poincar\'e symmetry preserved on a
noncommutative Moyal plane with light-like noncommutativity. Moreover, we show
that the three subgroups relevant to the Cohen-Glashow VSR can also be realized
in the noncommutative space-time setting. For all these three cases the
noncommutativity parameter $\theta^{\mu\nu}$ should be light-like
($\theta^{\mu\nu}\theta_{\mu\nu}=0$). A fixed constant noncommutativity
parameter respects the T(2) subgroup of Lorentz, while for the E(2) and SIM(2)
cases the form of noncommutativity among the coordinates should be of linear
(Lie algebra) and quadratic (quantum group) type, respectively. We discuss some
physical implications of this realization of the Cohen-Glashow VSR.


title: On the Briancon-Skoda theorem on a singular variety

abstract:
  Let $Z$ be a germ of a reduced analytic space of pure dimension. We provide
an analytic proof of the uniform Briancon-Skoda theorem for the local ring
$\mathcal{O}_Z$; a result which was previously proved by Huneke by algebraic
methods. For ideals with few generators we also get much sharper results.


title: On the Chemical Potential of Dark Energy

abstract:
  It is widely assumed that the observed universe is accelerating due to the
existence of a new fluid component called dark energy. In this article, the
thermodynamics consequences of a nonzero chemical potential on the dark energy
component is discussed with special emphasis to the phantom fluid case. It is
found that if the dark energy fluid is endowed with a negative chemical
potential, the phantom field hypothesis becomes thermodynamically consistent
with no need of negative temperatures as recently assumed in the literature.


title:
Optimal time and space regularity for solutions of degenerate
  differential equations

abstract:
  We derive optimal regularity, in both time and space, for solutions of the
Cauchy problem related to a degenerate differential equation in a Banach space
X. Our results exhibit a sort of prevalence for space regularity, in the sense
that the higher is the order of regularity with respect to space, the lower is
the corresponding order of regularity with respect to time.


title:
Ground-state alignment of atoms and ions: New Diagnostics of
  Astrophysical Magnetic field in diffuse medium

abstract:
  We discuss a new technique of studying magnetic fields in diffuse
astrophysical media, e.g. interstellar and intergalactic gas/plasma. This
technique is based on the angular momentum alignment of atoms and ions in their
ground or metastable states. As the life-time of atoms in such states is long,
the alignment induced by anisotropic radiation is susceptible to weak magnetic
fields ($1{\rm G}\gtrsim B\gtrsim0.1\mu$G). The alignment reveals itself in
terms of the polarization of the absorbed and emitted light. A variety of atoms
with fine or hyperfine splitting of the ground or metastable states exhibit the
alignment and the resulting polarization degree in some cases exceeds 20%. We
show that in the case of absorption the polarization direction is either
parallel or perpendicular to magnetic field, while more complex dependencies
emerge for the case of emission of aligned atoms. We show that the
corresponding studies of magnetic fields can be performed with optical and UV
polarimetry. A unique feature of these studies is that they can reveal the 3D
orientation of magnetic field.
  In addition, we point out that the polarization of the radiation arising from
the transitions between fine and hyperfine states of the ground level can
provide yet another promising diagnostics of magnetic fields, including the
magnetic fields in the Early Universe. We mention several cases of
interplanetary, circumstellar and interstellar magnetic fields for which the
studies of magnetic fields using ground state atomic alignment effect are
promising.


title:
The generalized scaling function of AdS/CFT and semiclassical string
  theory

abstract:
  Recently, Freyhult, Rej and Staudacher (FRS) proposed an integral equation
determining the leading logarithmic term of the anomalous dimension of sl(2)
twist-operators in N=4 SYM for large Lorentz spin M and twist L at fixed j =
L/log(M). We discuss the large j limit of the FRS equation. This limit can be
matched with the {\em fast long string} limit of AdS_5 X S^5 superstring
perturbation theory at all couplings. In particular, a certain part of the
classical and one-loop string result is known to be protected and can be
computed in the weakly coupled large-j limit of the FRS equation. We present
various analytical and numerical results supporting agreement at one and two
loops in the gauge theory.


title: The Amati relation in the "fireshell" model

abstract:
  (Shortened) CONTEXT: [...] AIMS: Motivated by the relation proposed by Amati
and collaborators, we look within the ``fireshell'' model for a relation
between the peak energy E_p of the \nu F_\nu total time-integrated spectrum of
the afterglow and the total energy of the afterglow E_{aft}, which in our model
encompasses and extends the prompt emission. METODS: [...] Within the fireshell
model [...] We can then build two sets of ``gedanken'' GRBs varying the total
energy of the electron-positron plasma E^{e^\pm}_{tot} and keeping the same
baryon loading B of GRB050315. The first set assumes for the effective CBM
density the one obtained in the fit of GRB050315. The second set assumes
instead a constant CBM density equal to the average value of the GRB050315
prompt phase. RESULTS: For the first set of ``gedanken'' GRBs we find a
relation E_p\propto (E_{aft})^a, with a = 0.45 \pm 0.01, whose slope strictly
agrees with the Amati one. Such a relation, in the limit B \to 10^{-2},
coincides with the Amati one. Instead, in the second set of ``gedanken'' GRBs
no correlation is found. CONCLUSIONS: Our analysis excludes the Proper-GRB
(P-GRB) from the prompt emission, extends all the way to the latest afterglow
phases and is independent on the assumed cosmological model, since all
``gedanken'' GRBs are at the same redshift. The Amati relation, on the other
hand, includes also the P-GRB, focuses on the prompt emission only, and is
therefore influenced by the instrumental threshold which fixes the end of the
prompt emission, and depends on the assumed cosmology. This may well explain
the intrinsic scatter observed in the Amati relation.


title: Integral representation of renormalized self-intersection local times

abstract:
  In this paper we apply Clark-Ocone formula to deduce an explicit integral
representation for the renormalized self-intersection local time of the $d$%
-dimensional fractional Brownian motion with Hurst parameter $H\in (0,1)$.
  As a consequence, we derive the existence of some exponential moments for
this random variable.


title: Spin-resolved quantum-dot resonance fluorescence

abstract:
  In the quest for physically realizable quantum information science (QIS)
primitives, self-assembled quantum dots (QDs) serve a dual role as sources of
photonic (flying) qubits and traps for electron spin; the prototypical
stationary qubit. Here we demonstrate the first observation of spin-selective,
near background-free and transform-limited photon emission from a resonantly
driven QD transition. The hallmark of resonance fluorescence, i.e. the Mollow
triplet in the scattered photon spectrum when an optical transition is driven
resonantly, is presented as a natural way to spectrally isolate the photons of
interest from the original driving field. We go on to demonstrate that the
relative frequencies of the two spin-tagged photon states are tuned independent
of an applied magnetic field via the spin-selective dynamic Stark effect
induced by the very same driving laser. This demonstration enables the
realization of challenging QIS proposals such as heralded single photon
generation for linear optics quantum computing, spin-photon entanglement, and
dipolar interaction mediated quantum logic gates. From a spectroscopy
perspective, the spin-selective dynamic Stark effect tunes the QD spin-state
splitting in the ground and excited states independently, thus enabling
previously inaccessible regimes for controlled probing of mesoscopic spin
systems.


title: Atlas-Based Prostate Segmentation Using an Hybrid Registration

abstract:
  Purpose: This paper presents the preliminary results of a semi-automatic
method for prostate segmentation of Magnetic Resonance Images (MRI) which aims
to be incorporated in a navigation system for prostate brachytherapy. Methods:
The method is based on the registration of an anatomical atlas computed from a
population of 18 MRI exams onto a patient image. An hybrid registration
framework which couples an intensity-based registration with a robust
point-matching algorithm is used for both atlas building and atlas
registration. Results: The method has been validated on the same dataset that
the one used to construct the atlas using the "leave-one-out method". Results
gives a mean error of 3.39 mm and a standard deviation of 1.95 mm with respect
to expert segmentations. Conclusions: We think that this segmentation tool may
be a very valuable help to the clinician for routine quantitative image
exploitation.


title: On arithmetic partitions of Z_n

abstract:
  Generalizing a classical problem in enumerative combinatorics, Mansour and
Sun counted the number of subsets of $\Z_n$ without certain separations. Chen,
Wang, and Zhang then studied the problem of partitioning $\Z_n$ into
arithmetical progressions of a given type under some technical conditions. In
this paper, we improve on their main theorems by applying a convolution formula
for cyclic multinomial coefficients due to Raney-Mohanty.


title: How Is Meaning Grounded in Dictionary Definitions?

abstract:
  Meaning cannot be based on dictionary definitions all the way down: at some
point the circularity of definitions must be broken in some way, by grounding
the meanings of certain words in sensorimotor categories learned from
experience or shaped by evolution. This is the "symbol grounding problem." We
introduce the concept of a reachable set -- a larger vocabulary whose meanings
can be learned from a smaller vocabulary through definition alone, as long as
the meanings of the smaller vocabulary are themselves already grounded. We
provide simple algorithms to compute reachable sets for any given dictionary.


title: Charm and hidden charm scalar mesons in the nuclear medium

abstract:
  We study the renormalization of the properties of low lying charm and hidden
charm scalar mesons in a nuclear medium, concretely of the D_{s0}(2317) and the
theoretical hidden charm state X(3700). We find that for the D_{s0}(2317), with
negligible width at zero density, the width becomes about 100 MeV at normal
nuclear matter density, while in the case of the X(3700) the width becomes as
large as 200 MeV. We discuss the origin of this new width and trace it to
reactions occurring in the nucleus, while offering a guideline for future
experiments testing these changes. We also show how those medium modifications
will bring valuable information on the nature of the scalar resonances and the
mechanisms of the interaction of D mesons with nucleons and nuclei.


title:
Principal bundles, quasi-abelian varieties and structure of algebraic
  groups

abstract:
  We classify principal bundles over anti-affine schemes with affine and
commutative structural group. We show that this yields the classification of
quasi-abelian varieties over a field k (i.e., group k-schemes with no non
constant global functions). The interest of this result is given by the fact
that the classification of smooth group k-schemes is reduced to the
classification of quasi-abelian varieties and of certain affine group schemes.


title: Cosmic Rays and the Search for a Lorentz Invariance Violation

abstract:
  This is an introductory review about the on-going search for a signal of
Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic
aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We
discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons,
which is predicted due to photopion production in the Cosmic Microwave
Background (CMB). This is a process of modest energy in the proton rest frame.
It can be investigated to a high precision in the laboratory, if Lorentz
transformations apply even at factors $\gamma \sim O(10^{11})$. For heavier
nuclei the energy attenuation is even faster due to photo-disintegration, again
if this process is Lorentz invariant. Hence the viability of Lorentz symmetry
up to tremendous gamma-factors - far beyond accelerator tests - is a central
issue. Next we comment on conceptual aspects of Lorentz Invariance and the
possibility of its spontaneous breaking. This could lead to slightly particle
dependent ``Maximal Attainable Velocities''. We discuss their effect in decays,
Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We
also review the search for LIV in cosmic gamma-rays. For multi TeV gamma-rays
we possibly encounter another puzzle related to the transparency of the CMB,
similar to the GZK cutoff. The photons emitted in a Gamma Ray Burst occur at
lower energies, but their very long path provides access to information not far
from the Planck scale. No LIV has been observed so far. However, even extremely
tiny LIV effects could change the predictions for cosmic ray physics
drastically. An Appendix is devoted to the recent hypothesis by the Pierre
Auger Collaboration, which identifies nearby Active Galactic Nuclei - or
objects next to them - as probable UHECR sources.


title:
X-ray spectra from magnetar candidates. II Resonant cross sections for
  electron-photon scattering in the relativistic regime

abstract:
  Recent models of spectral formation in magnetars called renewed attention on
electron-photon scattering in the presence of ultra-strong magnetic fields.
Investigations presented so far mainly focussed on mildly relativistic
particles and magnetic scattering was treated in the non-relativistic (Thomson)
limit. This allows for consistent spectral calculations up to a few tens of
keVs, but becomes inadequate in modelling the hard tails (<200 keV) detected by
INTEGRAL from magnetar sources. In this paper, the second in a series devoted
to model the X-/soft gamma-ray persistent spectrum of magnetar candidates, we
present explicit, relatively simple expressions for the magnetic Compton
cross-section at resonance which account for Landau-Raman scattering up to the
second Landau level. No assumption is made on the magnetic field strength. We
find that sensible departures from the Thomson regime can bealready present at
B ~5E12 G. The form of the magnetic cross section we derived can be easily
implemented in Monte Carlo transfer codes and a direct application to magnetar
spectral calculations will be presented in a forthcoming study.


title:
Long-wavelength excesses of FU Orionis objects: flared outer disks or
  infalling envelopes?

abstract:
  The mid- to far-infrared emission of the outbursting FU Orionis objects has
been attributed either to a flared outer disk or to an infalling envelope. We
revisit this issue using detailed radiative transfer calculations to model the
recent, high signal-to-noise data from the IRS instrument on the {Spitzer Space
Telescope}. In the case of FU Ori, we find that a physically-plausible flared
disk irradiated by the central accretion disk matches the observations.
Building on our previous work, our accretion disk model with outer disk
irradiation by the inner disk reproduces the spectral energy distribution
between ~4000 angstroms to ~40 microns. Our model is consistent with
near-infrared interferometry but there are some inconsistencies with
mid-infared interferometric results. Including the outer disk allows us to
refine our estimate of the outer radius of the outbursting, high mass accretion
rate disk in FU Ori as ~ 0.5 AU, which is a crucial parameter in assessing
theories of the FU Orionis phenomenon. We are able to place an upper limit on
the mass infall rate of any remnant envelope infall rate to ~ 7e-7 Msun/yr
assuming a centrifugal radius of 200 AU. The FUor BBW 76 is also well modelled
by a 0.6 AU inner disk and a flared outer disk. However, V1515 Cyg requires an
envelope with an outflow cavity to adequately reproduce the IRS spectrum. In
contrast with the suggestion by Green et al., we do not require a flattened
envelope to match the observations; the inferred cavity shape is qualitatively
consistent with typical protostellar envelopes. This variety of dusty
structures suggests that the FU Orionis phase can be present at either early or
late stages of protostellar evolution.


title:
Counterion correlations near charged surfaces: from the weak to the
  strong coupling regime

abstract:
  A simple field theory approach is developed to model the properties of
charged, dielectric bodies and their associated counterions. This predictive
theory is able to accurately describe the properties of systems (as compared to
computer simulation data) from the weak coupling limit, where the
Poisson-Boltzmann theory works well, through to the strong coupling limit. In
particular, it is able to quantitatively describe the attraction between
like-charged plates and the influence of image charge interactions.


title: Long Term Evolution of Magnetized Bubbles in Galaxy Clusters

abstract:
  We have performed nonlinear ideal magnetohydrodynamic simulations of the long
term evolution of a magnetized low-density "bubble" plasma formed by a radio
galaxy in a stratified cluster medium. It is found that about 3.5% of the
initial magnetic energy remains in the bubble after $\sim 8 \times 10^{9}$
years, and the initial magnetic bubble expansion is adiabatic. The bubble can
survive for at least $8 \times 10^9$ years due to the stabilizing effect of the
bubble magnetic field on Rayleigh-Taylor and Kelvin-Holmholtz instabilities,
possibly accounting for "ghost cavities" as observed in Perseus-A\@. A filament
structure spanning about 500 kpc is formed along the path of bubble motion. The
mean value of the magnetic field inside this structure is $\sim 0.88$ $\mu$G at
$\sim8\times10^9$ years. Finally, the initial bubble momentum and rotation have
limited influence on the long term evolution of the bubble.


title: Casimir force in O(n) lattice models with a diffuse interface

abstract:
  On the example of the spherical model we study, as a function of the
temperature $T$, the behavior of the Casimir force in O(n) systems with a
diffuse interface and slab geometry $\infty^{d-1}\times L$, where $2<d<4$ is
the dimensionality of the system. We consider a system with nearest-neighbor
anisotropic interaction constants $J_\parallel$ parallel to the film and
$J_\perp$ across it. The model represents the $n\to\infty$ limit of O(n) models
with antiperiodic boundary conditions applied across the finite dimension $L$
of the film. We observe that the Casimir amplitude $\Delta_{\rm
Casimir}(d|J_\perp,J_\parallel)$ of the anisotropic $d$-dimensional system is
related to that one of the isotropic system $\Delta_{\rm Casimir}(d)$ via
$\Delta_{\rm Casimir}(d|J_\perp,J_\parallel)=(J_\perp/J_\parallel)^{(d-1)/2}
\Delta_{\rm Casimir}(d)$. For $d=3$ we find the exact Casimir amplitude $
\Delta_{\rm Casimir}= [ {\rm Cl}_2 (\pi/3)/3-\zeta
  (3)/(6 \pi)](J_\perp/J_\parallel)$, as well as the exact scaling functions of
the Casimir force and of the helicity modulus $\Upsilon(T,L)$. We obtain that
$\beta_c\Upsilon(T_c,L)=(2/\pi^{2}) [{\rm Cl}_2(\pi/3)/3+7\zeta(3)/(30\pi)]
(J_\perp/J_\parallel)L^{-1}$, where $T_c$ is the critical temperature of the
bulk system. We find that the effect of the helicity is thus strong that the
Casimir force is repulsive in the whole temperature region.


title:
Accurate determination of tensor network state of quantum lattice models
  in two dimensions

abstract:
  We have proposed a novel numerical method to calculate accurately the
physical quantities of the ground state with the tensor-network wave function
in two dimensions. We determine the tensor network wavefunction by a projection
approach which applies iteratively the Trotter-Suzuki decomposition of the
projection operator and the singular value decomposition of matrix. The norm of
the wavefunction and the expectation value of a physical observable are
evaluated by a coarse grain renormalization group approach. Our method allows a
tensor-network wavefunction with a high bond degree of freedom (such as D=8) to
be handled accurately and efficiently in the thermodynamic limit. For the
Heisenberg model on a honeycomb lattice, our results for the ground state
energy and the staggered magnetization agree well with those obtained by the
quantum Monte Carlo and other approaches.

categories: cond-mat.str-el cond-mat.stat-mech physics.comp-ph quant-ph


title:
Complex magnetic monopoles, geometric phases and quantum evolution in
  vicinity of diabolic and exceptional points

abstract:
  We consider the geometric phase and quantum tunneling in vicinity of diabolic
and exceptional points. We show that the geometric phase associated with the
degeneracy points is defined by the flux of complex magnetic monopole. In
weak-coupling limit the leading contribution to the real part of geometric
phase is given by the flux of the Dirac monopole plus quadrupole term, and the
expansion for its imaginary part starts with the dipolelike field. For a
two-level system governed by the generic non-Hermitian Hamiltonian, we derive a
formula to compute the non-adiabatic complex geometric phase by integral over
the complex Bloch sphere. We apply our results to to study a two-level
dissipative system driven by periodic electromagnetic field and show that in
the vicinity of the exceptional point the complex geometric phase behaves as
step-like function. Studying tunneling process near and at exceptional point,
we find two different regimes: coherent and incoherent. The coherent regime is
characterized by the Rabi oscillations and one-sheeted hyperbolic monopole
emerges in this region of the parameters. In turn with the incoherent regime
the two-sheeted hyperbolic monopole is associated. The exceptional point is the
critical point of the system where the topological transition occurs and both
of the regimes yield the quadratic dependence on time. We show that the
dissipation brings into existence of pulses in the complex geometric phase and
the pulses are disappeared when dissipation dies out. Such a strong coupling
effect of the environment is beyond of the conventional adiabatic treatment of
the Berry phase.


title: Distinguished Orbits of Reductive Groups

abstract:
  We prove a generalization of a theorem of Borel-Harish-Chandra on closed
orbits of linear actions of reductive groups.
  Consider a real reductive algebraic group $G$ acting linearly and rationally
on a real vector space $V$. $G$ can be viewed as the real points of a complex
reductive group $G^\mathbb C$ which acts on $V^\mathbb C := V \otimes \mathbb
C$. Borel-Harish-Chandra show that $G^\mathbb C \cdot v \cap V$ is a finite
union of $G$-orbits; moreover, $G^\mathbb C \cdot v$ is closed if and only if
$G\cdot v$ is closed. We show that the same result holds not just for closed
orbits but for the so-called distinguished orbits. An orbit is called
distinguished if it contains a critical point of the norm squared of the moment
map on projective space. Our main result compares the complex and real settings
to show $G\cdot v$ is distinguished if and only if $G^\mathbb C \cdot v$ is
distinguished.
  In addition, we show that if an orbit is distinguished, then under the
negative gradient flow of the norm squared of the moment map the entire
$G$-orbit collapses to a single $K$-orbit. This result holds in both the
complex and real settings.
  We finish with some applications to the study of the left-invariant geometry
of Lie groups.


title: On the difference between solutions of discrete tomography problems

abstract:
  We consider the problem of reconstructing binary images from their horizontal
and vertical projections. We present a condition that the projections must
necessarily satisfy when there exist two disjoint reconstructions from those
projections. More generally, we derive an upper bound on the symmetric
difference of two reconstructions from the same projections. We also consider
two reconstructions from two different sets of projections and prove an upper
bound on the symmetric difference in this case.


title:
Short-length storage of intense optical pulses in solid by adiabatic
  passage

abstract:
  We propose a novel scheme of storage of intense pulses which allows a
significant reduction of the storage length with respect to standard schemes.
This scheme is particularly adapted to store optical information in media with
fast relaxations.


title: Role of Many-particle excitations in Coulomb Blockaded Transport

abstract:
  We discuss the role of electron-electron and electron-phonon correlations in
current flow in the Coulomb Blockade regime, focusing specifically on
nontrivial signatures arising from the break-down of mean-field theory. By
solving transport equations directly in Fock space, we show that
electron-electron interactions manifest as gateable excitations experimentally
observed in the current-voltage characteristic. While these excitations might
merge into an incoherent sum that allows occasional simplifications, a clear
separation of excitations into slow `traps' and fast `channels' can lead to
further novelties such as negative differential resistance, hysteresis and
random telegraph signals. Analogous novelties for electron-phonon correlation
include the breakdown of commonly anticipated Stokes-antiStokes intensities,
and an anomalous decrease in phonon population upon heating due to reabsorption
of emitted phonons.


title:
Transport Coefficients of Non-Newtonian Fluid and Causal Dissipative
  Hydrodynamics

abstract:
  A new formula to calculate the transport coefficients of the causal
dissipative hydrodynamics is derived by using the projection operator method
(Mori-Zwanzig formalism) in [T. Koide, Phys. Rev. E75, 060103(R) (2007)]. This
is an extension of the Green-Kubo-Nakano (GKN) formula to the case of
non-Newtonian fluids, which is the essential factor to preserve the
relativistic causality in relativistic dissipative hydrodynamics. This formula
is the generalization of the GKN formula in the sense that it can reproduce the
GKN formula in a certain limit. In this work, we extend the previous work so as
to apply to more general situations.


title: Large Berry phases in layered graphene

abstract:
  Brillouin zones of graphene systems possess Dirac points, where band
degeneracies occur. We study the variety of (and large magnitude) phases that
the electronic states can acquire when a uniform time-dependent electric field
carries the electrons around one or more Dirac points in a non-concentric
fashion. An experimentally accessible determination of excess Berry phases is
proposed involving the Zitterbewegung of electronic current near an
orthogonality point in adiabatic motion.


title: On the moduli space of elliptic Maxwell-Chern-Simons theories

abstract:
  We analyze the moduli space of the low-energy limit of 3-dimensional N=3
Maxwell-Chern-Simons theories described by circular quiver diagrams, as for
4-dimensional elliptic models. We define the theories by using
D3-NS5-(k,1)5-brane systems with an arbitrary number of fivebranes. The
supersymmetry is expected to be enhanced to N=4 in the low-energy limit. We
show that the Higgs branch, in which all bifundamental scalar fields develop
vacuum expectation values, is an abelian orbifold of C^4. We confirm that the
same geometry is obtained as an M-theory dual of the brane system. We also
consider theories realized by introducing more than two kinds of fivebranes,
and obtain nontoric fourfolds as moduli spaces.


title: Ricci-flat K\"ahler metrics on crepant resolutions of K\"ahler cones

abstract:
  We prove that a crepant resolution of a Ricci-flat K\"ahler cone X admits a
complete Ricci-flat K\"ahler metric asymptotic to the cone metric in every
K\"ahler class in H^2_c(Y,R). This result contains as a subcase the existence
of ALE Ricci-flat K\"ahler metrics on crepant resolutions of X=C^n /G, where G
is a finite subgroup of SL(n,C).
  We consider the case in which X is toric. A result of A. Futaki, H. Ono, and
G. Wang guarantees the existence of a Ricci-flat K\"ahler cone metric if X is
Gorenstein. We use toric geometry to construct crepant resolutions.


title: The Progenitors of Type Ia Supernovae

abstract:
  Type Ia supernovae (SNe Ia) occur in both old, passive galaxies and active,
star-forming galaxies. This fact, coupled with the strong dependence of SN Ia
rate on star formation rate, suggests that SNe Ia form from stars with a wide
range of ages. Here we show that the rate of SN Ia explosions is about 1% of
the stellar death rate, independent of star formation history. The dependence
of SN Ia rate on star formation rate implies a delay time distribution
proportional to t^{-0.5+-0.2}. The single degenerate channel for SNe Ia can be
made to match the observed SN Ia rate -- SFR relation, but only if white dwarfs
are converted to SNe Ia with uniform efficiency of ~1%, independent of mass.
Since low-mass progenitors are expected to have lower conversion efficiencies
than high mass progenitors, we conclude that some other progenitor scenario
must be invoked to explain some, or perhaps all, SNe Ia.


title:
A Renormalisation Group approach to Stochastic L{\oe}wner Evolutions and
  the Doob h-transform

abstract:
  In this notes we shall describe the relation of a certain class of simple
random curves arising in 2D statistical mechanics models in the scaling limit,
which can be described dynamically by Stochastic L{\oe}wner Evolutions (SLE),
and the equivalent Renormalisation Group (RG) theoretic interpretation in
Conformal Field Theory, as a fixed point of the RG flow. Further, we shall
recall the relation of this random curves with String Theory, and how one can
derive a general measure on such random paths, by using weighted regularised
determinants, which come from sections of twisted line bundles. Importantly,
the null vector at level two in the Verma module for the highest-weight
representation of the Virasoro algebra corresponds to a generalised Doob-Getoor
h-transform.


title:
Twofold advance in the theoretical understanding of far-from-equilibrium
  properties of interacting nanostructures

abstract:
  We calculate the full $I-V$ characteristics at vanishing temperature in the
self-dual interacting resonant level model in two ways. The first uses careful
time dependent DMRG with large number of states per block and a representation
of the reservoirs as leads subjected to a chemical potential. The other is
based on integrability in the continuum limit, and generalizes early work of
Fendley Ludwig Saleur on the boundary sine-Gordon model. The two approaches are
in excellent agreement, and uncover among other things a power law decay of the
current at large voltages when $U>0$.


title:
An axisymmetric hydrodynamical model for the torus wind in AGN. II:
  X-ray excited funnel flow

abstract:
  We have calculated a series of models of outflows from the obscuring torus in
active galactic nuclei (AGN). Our modeling assumes that the inner face of a
rotationally supported torus is illuminated and heated by the intense X-rays
from the inner accretion disk and black hole. As a result of such heating a
strong biconical outflow is observed in our simulations. We calculate
3-dimensional hydrodynamical models, assuming axial symmetry, and including the
effects of X-ray heating, ionization, and radiation pressure. We discuss the
behavior of a large family of these models, their velocity fields, mass fluxes
and temperature, as functions of the torus properties and X-ray flux. Synthetic
warm absorber spectra are calculated, assuming pure absorption, for sample
models at various inclination angles and observing times. We show that these
models have mass fluxes and flow speeds which are comparable to those which
have been inferred from observations of Seyfert 1 warm absorbers, and that they
can produce rich absorption line spectra.


title:
An invariant of embeddings of 3-manifolds in 6-manifolds and Milnor's
  triple linking number

abstract:
  We give a simple axiomatic definition of a rational-valued invariant s(W,V,e)
of triples (W,V,e), where W is a (smooth, oriented, closed) 6-manifold and V is
a 3-submanifold of W, and where e is a second rational cohomology class of the
complement of V satisfying a certain condition. The definition is stated in
terms of cobordisms of such triples and the signature of 4-manifolds. When W =
S^6 and V is a smoothly embedded 3-sphere, and when e/2 is the Poincare dual of
a Seifert surface of V, the invariant coincides with -8 times Haefliger's
embedding invariant of (S^6,V). Our definition recovers a more general
invariant due to Takase, and contains a new definition for Milnor's triple
linking number of algebraically split 3-component links in R^3 that is close to
the one given by the perturbative series expansion of the Chern-Simons theory
of links in R^3.


title: Characterization of Protein Folding by Dominant Reaction Pathways

abstract:
  We assess the reliability of the recently developed approach denominated
Dominant Reaction Pathways (DRP) by studying the folding of a 16-residue
beta-hairpin, within a coarse-grained Go-type model. We show that the DRP
predictions are in quantitative agreement with the results of Molecular
Dynamics simulations, performed in the same model. On the other hand, in the
DRP approach, the computational difficulties associated to the decoupling of
time scales are rigorously bypassed. The analysis of the important transition
pathways supports a picture of the beta-hairpin folding in which the reaction
is initiated by the collapse of the hydrophobic cluster.


title:
On the FP-ghost propagators for Yang-Mills theories and perturbative
  quantum gravity in the covariant gauge in de Sitter spacetime

abstract:
  The propagators of the Faddeev-Popov (FP) ghosts for Yang-Mills theories and
perturbative quantum gravity in the covariant gauge are infrared (IR) divergent
in de Sitter spacetime. We point out, however, that the modes responsible for
these divergences will not contribute to loop diagrams in computations of
time-ordered products in either Yang-Mills theories or perturbative quantum
gravity. Therefore we propose that the IR divergent FP-ghost propagator should
be regularized by a small mass term that is sent to zero in the end of any
perturbative calculations. This proposal is equivalent to using the effective
FP-ghost propagators, which we present in an explicit form, obtained by
removing the modes responsible for the IR divergences. We also make some
comments on the corresponding propagators in anti-de Sitter spacetime.


title:
Low energy excitations in CoO studied by temperature dependent x-ray
  absorption spectroscopy

abstract:
  We have measured the intricate temperature dependence of the Co L2,3 x-ray
absorption spectra (2p-3d excitations) of CoO. To allow for accurate total
electron yield measurements, the material has been grown in thin film form on a
metallic substrate in order to avoid charging problems usually encountered
during electron spectroscopic studies on bulk CoO samples. The changes in
spectra due to temperature are in good agreement with detailed ligand-field
calculations indicating that these changes are mostly due to thermal population
of closely lying excited states, originating from degenerate t2g levels lifted
by the spin-orbit coupling. Magnetic coupling in the ordered phase, modeled as
a mean-field exchange field, mixes in excited states inducing a tetragonal
charge density. The spin-orbit coupling induced splitting of the low energy
states results in a non-trivial temperature dependence for the magnetic
susceptibility.


title: Structural stability and lattice dynamics of SiO2 cristobalite

abstract:
  Among the phases of SiO2 are alpha and beta cristobalites, which have a long
and somewhat controversial history of proposed structural assignments and
phase-transition mechanisms. Recently, Zhang and Scott found new indications
that the higher-temperature beta phase has space group I-42d and, by assuming a
group-subgroup relationship between phases, they argued that the
lower-temperature alpha phase should have lower symmetry than that of the
widely-accepted P4_12_12 space group. With this motivation, we use
first-principles calculations to investigate the energy, structure, and local
stability of P4_12_12 and I-42d structures. We also compute the frequencies of
the zone-center phonon modes in both structures, as well as certain
zone-boundary modes in the I-42d structure, and compare with experiment. We
then argue that the various P4_12_12 and I-42d enantiomorphs can be grouped
into three clusters, each of which is identified with a three-dimensional
manifold of structures of P2_12_12_1 symmetry in which the P4_12_12 and I-42d
appear as higher-symmetry special cases. We find that there are relatively high
energy barriers between manifolds, but low barriers within a manifold.
Exploring the energy landscape within one of these manifolds, we find a
minimal-energy path connecting P4_12_12 and I-42d structures with a
surprisingly low barrier of ~5 meV per formula unit. Possible implications for
the phase-transition mechanism are discussed.


title:
The Influence of Sodium and Potassium Dynamics on Excitability,
  Seizures, and the Stability of Persistent States: I. Single Neuron Dynamics

abstract:
  In these companion papers, we study how the interrelated dynamics of sodium
and potassium affect the excitability of neurons, the occurrence of seizures,
and the stability of persistent states of activity. In this first paper, we
construct a mathematical model consisting of a single conductance-based neuron
together with intra- and extracellular ion concentration dynamics. We formulate
a reduction of this model that permits a detailed bifurcation analysis, and
show that the reduced model is a reasonable approximation of the full model. We
find that competition between intrinsic neuronal currents, sodium-potassium
pumps, glia, and diffusion can produce very slow and large-amplitude
oscillations in ion concentrations similar to what is seen physiologically in
seizures. Using the reduced model, we identify the dynamical mechanisms that
give rise to these phenomena. These models reveal several experimentally
testable predictions. Our work emphasizes the critical role of ion
concentration homeostasis in the proper functioning of neurons, and points to
important fundamental processes that may underlie pathological states such as
epilepsy.


title: A sharp bound for the reconstruction of partitions

abstract:
  Answering a question of Cameron, Pretzel and Siemons proved that every
integer partition of $n\ge 2(k+3)(k+1)$ can be reconstructed from its set of
$k$-deletions. We describe a new reconstruction algorithm that lowers this
bound to $n\ge k^2+2k$ and present examples showing that this bound is best
possible.


title: Cohomology and Support Varieties for Lie Superalgebras of Type W(n)

abstract:
  Boe, Kujawa and Nakano recently investigated relative cohomology for
classical Lie superalgebras and developed a theory of support varieties. The
dimensions of these support varieties give a geometric interpretation of the
combinatorial notions of defect and atypicality due to Kac, Wakimoto, and
Serganova. In this paper we calculate the cohomology ring of the Cartan type
Lie superalgebra W(n) relative to the degree zero component W(n)_{0} and show
that this ring is a finitely generated polynomial ring. This allows one to
define support varieties for finite dimensional W(n)-supermodules which are
completely reducible over W(n)_{0}. We calculate the support varieties of all
simple supermodules in this category. Remarkably our computations coincide with
the prior notion of atypicality for Cartan type superalgebras due to Serganova.
We also present new results on the realizability of support varieties which
hold for both classical and Cartan type superalgebras.


title:
The Influence of Sodium and Potassium Dynamics on Excitability,
  Seizures, and the Stability of Persistent States: II. Network and Glial
  Dynamics

abstract:
  In these companion papers, we study how the interrelated dynamics of sodium
and potassium affect the excitability of neurons, the occurrence of seizures,
and the stability of persistent states of activity. We seek to study these
dynamics with respect to the following compartments: neurons, glia, and
extracellular space. We are particularly interested in the slower time-scale
dynamics that determine overall excitability, and set the stage for transient
episodes of persistent oscillations, working memory, or seizures. In this
second of two companion papers, we present an ionic current network model
composed of populations of Hodgkin-Huxley type excitatory and inhibitory
neurons embedded within extracellular space and glia, in order to investigate
the role of micro-environmental ionic dynamics on the stability of persistent
activity. We show that these networks reproduce seizure-like activity if glial
cells fail to maintain the proper micro-environmental conditions surrounding
neurons, and produce several experimentally testable predictions. Our work
suggests that the stability of persistent states to perturbation is set by
glial activity, and that how the response to such perturbations decays or grows
may be a critical factor in a variety of disparate transient phenomena such as
working memory, burst firing in neonatal brain or spinal cord, up states,
seizures, and cortical oscillations.


title:
Analytical Calculation of the Neutrons Spectrum for Direct Measurement
  of N-N Scattering at Pulsed Reactor Yaguar

abstract:
  Analytical calculation of a single neutron detector counts per YAGUAR reactor
pulse is presented and comparison with coincidence scheme is given.


title: Regularity conditions for arbitrary Leavitt path algebras

abstract:
  We show that if $E$ is an arbitrary acyclic graph then the Leavitt path
algebra $L_K(E)$ is locally $K$-matricial; that is, $L_K(E)$ is the direct
union of subalgebras, each isomorphic to a finite direct sum of finite matrix
rings over the field $K$. As a consequence we get our main result, in which we
show that the following conditions are equivalent for an arbitrary graph $E$:
(1) $L_K(E)$ is von Neumann regular. (2) $L_K(E)$ is $\pi$-regular. (3) $E$ is
acyclic. (4) $L_K(E)$ is locally $K$-matricial. (5) $L_K(E)$ is strongly
$\pi$-regular. We conclude by showing how additional regularity conditions
(unit regularity, strongly clean) can be appended to this list of equivalent
conditions.


title: On super-massive objects without event horizon

abstract:
  This paper aims to show the possibility of the existence of super-massive
compact objects with radii less than the Schwarzschild one, which is one of the
principal consequences of the author's geodesic-invariant gravitation equations
(Ann. Phys. (Berlin), 17 (2008) 28). The physical interpretation of the
solutions of the equations is based on the conclusion that only an aggregate
"space-time geometry + used reference frame" has a physical sense.


title: SUSY backgrounds to Standard Model calibration processes at the LHC

abstract:
  One of the first orders of business for LHC experiments after beam turn-on
will be to calibrate the detectors using well understood Standard Model (SM)
processes such as W and Z production and ttbar production. These familiar SM
processes can be used to calibrate the electromagnetic and hadronic
calorimeters, and also to calibrate the associated missing transverse energy
signal. However, the presence of new physics may already affect the results
coming from these standard benchmark processes. We show that the presence of
relatively low mass supersymmetry (SUSY) particles may give rise to significant
deviations from SM predictions of Z+jets and W+jets events for jet multiplicity
$\ge 4$ or $\ge 5$, respectively. Furthermore, the presence of low mass SUSY
may cause non-standard deviations to appear in top quark invariant and
transverse mass distributions. Thus, effects that might be construed as
detector mal-performance could in fact be the presence of new physics. We
advocate several methods to check when new physics might be present within SM
calibration data.


title: Explaining the DAMA Signal with WIMPless Dark Matter

abstract:
  WIMPless dark matter provides a framework in which dark matter particles with
a wide range of masses naturally have the correct thermal relic density. We
show that WIMPless dark matter with mass around 2-10 GeV can explain the annual
modulation observed by the DAMA experiment without violating the constraints of
other dark matter searches. This explanation implies distinctive and promising
signals for other direct detection experiments, GLAST, and the LHC.


title:
Suzaku Observation of the Ophiuchus Galaxy Cluster: One of the Hottest
  Cool Core Clusters

abstract:
  We present the analysis of a Suzaku observation of the Ophiuchus galaxy
cluster. We confirmed that the cluster has a cool core. While the temperature
of the intracluster medium (ICM) decreases toward the center, the metal
abundance increases. Except for the core (r<~50 kpc), the cluster is hot (~9-10
keV) and is almost isothermal for r<~1 Mpc; the latter contradicts a previous
study. We do not detect the variation of the redshift of the ICM in the
cluster; the upper limit of the velocity difference is 3000 km s^-1. The iron
line ratios in X-ray spectra indicate that the ICM has reached the ionization
equilibrium state. From these results, we conclude that the Ophiuchus cluster
is not a major merger cluster but one of the hottest clusters with a cool core.
We obtain the upper limit of non-thermal emission from the cluster, which is
consistent with both the recent claimed detection with INTEGRAL and the recent
upper limits with the Swift/BAT. If the cluster has bright non-thermal emission
as suggested by the INTEGRAL measurement, it is probably not due to a recent
major cluster merger.


title: Characterizing the non-thermal emission of Cas A

abstract:
  We report on our analysis of the 1 Ms Chandra observation of the supernova
remnant Cas A in order to localize, characterize and quantify its non-thermal
X-ray emission. More specifically, we investigated whether the X-ray
synchrotron emission from the inside of the remnant is from the outward shock,
but projected toward the inner ring, or from the inner shell. We tackle this
problem by employing a Lucy-Richardson deconvolution technique and measuring
spectral indices in the 4.2-6 keV band.
  We show that most of the continuum emission is coming from an inner ring that
coincides with the location of the reverse shock. This inner ring includes
filaments, whose X-ray emission has been found to be dominated by X-ray
synchrotron emission. The X-ray emission from these filaments, both at the
forward shock and from the inner ring, have relatively hard spectra with
spectral index > -3.1. The regions emitting hard X-ray continuum contribute
about 54% of the total X-ray emission in the 4.2-6 keV. This is lower than
suggested by extrapolating the hard X-ray spectrum as measured by BeppoSAX-PDS
and INTEGRAL. This can be reconciled by assuming a gradual steepening of the
spectrum toward higher energies. We argue that the X-ray synchrotron emission
is mainly coming from the Western part of the reverse shock. The reverse shock
in the West is almost at rest in our observation frame, corresponding to a
relatively high reverse shock velocity of ~6000 km/s in the frame of the freely
expanding ejecta.


title:
A Pathfinder Instrument for Precision Radial Velocities in the
  Near-Infrared

abstract:
  We have designed and tested an in-plane echelle spectrograph configured to
investigate precision radial velocities from ground-based near-infrared
observations. The spectrograph operates across the spectral range of 0.9-1.7 mm
at a spectral resolution of R = 50,000, and uses a liquid nitrogen-cooled
HAWAII 1K detector. Repeated measurements of the Earth's rotation via
integrated Sunlight with two different instrument arrangements in the near
infrared Y band have produced radial velocities with ~10 m/s RMS over a period
of several hours. The most recent instrument configuration has achieved an
unbinned RMS of 7 m/s and suggests that infrared radial velocity precisions may
be able to approach those achieved at optical wavelengths.


title: Optical Interferometers with Reduced Sensitivity to Thermal Noise

abstract:
  A fundamental limit to the sensitivity of optical interferometry is thermal
noise that drives fluctuations in the positions of the surfaces of the
interferometer's mirrors, and thereby in the phase of the intracavity field.
Schemes for reducing this thermally driven phase noise are presented in which
phase shifts from concomitant strains at the surface and in the bulk of the
substrate compensate the phase shift due to the displacement of the surface.
Although the position of the physical surface fluctuates, the optical phase
upon reflection can have reduced sensitivity to this motion.


title: Lambda-effect from forced turbulence simulations

abstract:
  Aims: We determine the components of the $\Lambda$-effect tensor that
quantifies the contributions to the turbulent momentum transport even for
uniform rotation. Methods: Three-dimensional numerical simulations are used to
study turbulent transport in triply periodic cubes under the influence of
rotation and anisotropic forcing. Comparison is made with analytical results
obtained via the so-called minimal tau-approximation. Results: In the case
where the turbulence intensity in the vertical direction dominates, the
vertical stress is always negative. This situation is expected to occur in
stellar convection zones. The horizontal component of the stress is weaker and
exhibits a maximum at latitude 30 degrees - regardless of how rapid the
rotation is. The minimal tau-approximation captures many of the qualitative
features of the numerical results, provided the relaxation time tau is close to
the turnover time, i.e. the Strouhal number is of order unity.


title:
ACS imaging of star clusters in M51 II. The luminosity function and mass
  function across the disk

abstract:
  Whether or not there exists a physical upper mass limit for star clusters is
still unclear. HST/ACS data for the rich cluster population in the interacting
galaxy M51 enables us to investigate this in more detail. We investigate
whether the cluster luminosity function (LF) in M51 shows evidence for an upper
limit to the mass function. The variations of the LF parameters with position
on the disk are addressed. We determine the cluster LF for all clusters in M51
falling within our selection criteria, as well as for several subsets of the
sample. In that way we can determine the properties of the cluster population
as a function of galactocentric distance and background intensity. By comparing
observed and simulated LFs we can constrain the underlying cluster initial mass
function and/or cluster disruption parameters. A physical upper mass limit for
star clusters will appear as a bend dividing two power law parts in the LF, if
the cluster sample is large enough to sample the full range of cluster masses.
The location of the bend in the LF is indicative of the value of the upper mass
limit. The slopes of the power laws are an interplay between upper masses,
disruption and fading. The LF of the cluster population of M51 is better
described by a double power law than by a single power law. We show that the
cluster initial mass function is likely to be truncated at the high mass end.
We conclude from the variation of the LF parameters with galactocentric
distance that both the upper mass limit and the cluster disruption parameters
are likely to be a function of position in the galactic disk. At higher
galactocentric distances the maximum mass is lower, cluster disruption slower,
or both.


title:
Neutron Capture Rates near A=130 which Effect a Global Change to the
  r-Process Abundance Distribution

abstract:
  We investigate the impact of neutron capture rates near the A=130 peak on the
$r$-process abundance pattern. We show that these capture rates can alter the
abundances of individual nuclear species, not only in the region of A=130 peak,
but also throughout the abundance pattern. We discuss the nonequilibrium
processes that produce these abundance changes and determine which capture
rates have the most significant impact.


title: Quantum critical behavior in strongly interacting Rydberg gases

abstract:
  We study the appearance of correlated many-body phenomena in an ensemble of
atoms driven resonantly into a strongly interacting Rydberg state. The ground
state of the Hamiltonian describing the driven system exhibits a second order
quantum phase transition. We derive the critical theory for the quantum phase
transition and show that it describes the properties of the driven Rydberg
system in the saturated regime. We find that the suppression of Rydberg
excitations known as blockade phenomena exhibits an algebraic scaling law with
a universal exponent.


title:
A Population of Radio-loud Narrow Line Seyfert 1 Galaxies with
  Blazar-like Properties?

abstract:
  (abridged) We present a comprehensive study of a sample of 23 genuine
radio-loud NLS1 galaxies which have the radio-loudness parameters greater than
100. The radio sources of the sample are ubiquitously compact. A significant
fraction of these objects show interesting radio to X-ray properties that are
unusual to most of the previously known radio-loud NLS1 AGN, but are
reminiscent of blazars. These include flat radio spectra, large amplitude flux
and spectral variability, compact VLBI cores, very high brightness temperatures
derived from variability, enhanced optical emission in excess of the normal
ionising continuum, flat X-ray spectra, and blazar-like SEDs. We interpret them
as evidence for the postulated blazar nature of these very radio-loud NLS1 AGN,
which might possess at least moderately relativistic jets. Intrinsically, some
of the objects have relatively low radio power and would have been classified
as radio-intermediate AGN. The black hole masses are estimated to be within
10^{6-8}Msun, and the inferred Eddington ratios are around unity. The results
imply that radio-loud AGN may be powered by black holes with moderate masses
(10^{6-7}Msun) accreting at high rates. We find that a significant fraction of
the objects, despite having strong emission lines, resemble high-energy peaked
BL Lacs (HBL) in their SED. Given the peculiarities of blazar-like NLS1
galaxies, questions arise as to whether they are plain downsizing extensions of
normal radio-loud AGN, or whether they form a previously unrecognised
population.


title: A simple mechanism for the reversals of Earth's magnetic field

abstract:
  We show that a model, recently used to describe all the dynamical regimes of
the magnetic field generated by the dynamo effect in the VKS experiment [1],
also provides a simple explanation of the reversals of Earth's magnetic field,
despite strong differences between both systems.


title: A Simple Flavor Protection for RS

abstract:
  We present a simple variation of warped flavor models where the hierarchies
of fermion masses and mixings are still explained but dangerous flavor
violating effects in the Kaon sector are greatly reduced. The key new
ingredients are two horizontal U(1) symmetries. These symmetries forbid flavor
violation in the down quark sector (with the exception of small IR brane
localized kinetic mixing terms for the left-handed quarks) while allowing for
flavor violation in the up quark sector. The leading flavor constraints come
from D - anti-D mixing, and are safely satisfied for the KK mass scale of order
3 TeV. Our analysis of the flavor constraints also includes the constraints due
to the (usually ignored) localized kinetic mixing terms. We also comment on the
effects of the additional U(1) gauge bosons.


title: Searching for non-Gaussianity in the WMAP data

abstract:
  Some analyses of recent cosmic microwave background (CMB) data have provided
hints that there are deviations from Gaussianity in the WMAP CMB temperature
fluctuations. Given the far reaching consequences of such a non-Gaussianity for
our understanding of the physics of the early universe, it is important to
employ alternative indicators in order to determine whether the reported
non-Gaussianity is of cosmological origin, and/or extract further information
that may be helpful for identifying its causes. We propose two new
non-Gaussianity indicators, based on skewness and kurtosis of large-angle
patches of CMB maps, which provide a measure of departure from Gaussianity on
large angular scales. A distinctive feature of these indicators is that they
provide sky maps of non-Gaussianity of the CMB temperature data, thus allowing
a possible additional window into their origins. Using these indicators, we
find no significant deviation from Gaussianity in the three and five-year WMAP
ILC map with KQ75 mask, while the ILC unmasked map exhibit deviation from
Gaussianity, quantifying therefore the WMAP team recommendation to employ the
new mask KQ75 for tests of Gaussianity. We also use our indicators to test for
Gaussianity the single frequency foreground unremoved WMAP three and five-year
maps, and show that the K and Ka maps exhibit clear indication of deviation
from Gaussianity even with the KQ75 mask. We show that our findings are robust
with respect to the details of the method.


title:
Exponential stretching in filaments as fast dynamos in Euclidean and
  Riemannian 3D spaces

abstract:
  A new antidynamo theorem for non-stretched twisted magnetic flux tube dynamo
is obtained. Though Riemannian curvature cannot be neglected since one
considers curved magnetic flux tube axis, the stretch can be neglect since one
only considers the limit of thin magnetic flux tubes. The theorem states that
marginal or slow dynamos along curved (folded), torsioned (twisted) and
non-stretched flux tubes endowed with diffusionless plasma flows, if a
constraint is imposed on the relation between poloidal and toroidal magnetic
fields in the helical dynamo case. A formula for the stretch of flux tubes is
derived. From this formula one shows that the Riemann flux tube is stretched by
an interaction between the plasma flow vorticity and torsion, in accordance
with our physical intuition. Marginal diffusionless dynamos are shown to exist
obtained in the case of flux tube dynamos exponential stretching. Thus slow
dynamos can be obtaining on the flux tube under stretching. Filamentary dynamos
anti-dynamos are also considered. As flux tubes possess a magnetic axis
torsioned filament, it can also be considered as thegerm of a fast dynamo in
flux tubes Riemannian curved space. It is shown that for non-stretched
filaments only untwist and unfold filaments can provide dynamo action in
diffusive case. A condition for exponential stretching and fast dynamos in
filaments is given. These results are actually in agreement with Vishik
argument that fast dynamo cannot be obtained in non-stretched flows. Actually
the flux tube result is the converse of Vishik's lemma.


title:
A new perspective on the relation between dark energy perturbations and
  the late-time ISW effect

abstract:
  The effect of quintessence perturbations on the ISW effect is studied for a
mixed dynamical scalar field dark energy (DDE) and pressureless perfect fluid
dark matter. A new and general methodology is developed to track the growth of
the perturbations, which uses only the equation of state (EoS) parameter
$w_{\rm DDE} (z) \equiv p_{\rm DDE}/\rho_{\rm DDE}$ of the scalar field DDE,
and the initial values of the the relative entropy perturbation (between the
matter and DDE) and the intrinsic entropy perturbation of the scalar field DDE
as inputs. We also derive a relation between the rest frame sound speed
$\hat{c}_{s,{\rm DDE}}^2$ of an arbitrary DDE component and its EoS $w_{\rm
DDE} (z)$. We show that the ISW signal differs from that expected in a
$\Lambda$CDM cosmology by as much as +20% to -80% for parameterizations of
$w_{\rm DDE}$ consistent with SNIa data, and about $\pm$ 20% for
parameterizations of $w_{\rm DDE}$ consistent with SNIa+CMB+BAO data, at 95%
confidence. Our results indicate that, at least in principle, the ISW effect
can be used to phenomenologically distinguish a cosmological constant from DDE.


title: The Einstein-Weyl Equations, Scattering Maps, and Holomorphic Disks

abstract:
  We show that conformally compact, globally hyperbolic, Lorentzian
Einstein-Weyl 3-manifolds are in natural one-to-one correspondence with
orientation-reversing diffeomorphisms of the 2-sphere. The proof hinges on a
holomorphic-disk analog of Hitchin's mini-twistor correspondence.


title: Non Pauli-Fierz Massive Gravitons

abstract:
  We study general Lorentz invariant theories of massive gravitons. We show
that, contrary to the standard lore, there exist consistent theories where the
graviton mass term violates Pauli-Fierz structure. For theories where the
graviton is a resonance this does not imply the existence of a scalar ghost if
the deviation from Pauli-Fierz becomes sufficiently small at high energies.
These types of mass terms are required by any consistent realization of the DGP
model in higher dimension.


title: Shannon Meets Carnot: Generalized Second Thermodynamic Law

abstract:
  The classical thermodynamic laws fail to capture the behavior of systems with
energy Hamiltonian which is an explicit function of the temperature. Such
Hamiltonian arises, for example, in modeling information processing systems,
like communication channels, as thermal systems. Here we generalize the second
thermodynamic law to encompass systems with temperature-dependent energy
levels, $dQ=TdS+<d\mathcal{E}/dT>dT$, where $<\cdot>$ denotes averaging over
the Boltzmann distribution and reveal a new definition to the basic notion of
temperature. This generalization enables to express, for instance, the mutual
information of the Gaussian channel as a consequence of the fundamental laws of
nature - the laws of thermodynamics.


title:
Gravitational-wave Astronomy: Opening a New Window on the Universe for
  Students, Educators and the Public

abstract:
  The nascent field of gravitational-wave astronomy offers many opportunities
for effective and inspirational astronomy outreach. Gravitational waves, the
"ripples in space-time" predicted by Einstein's theory of General Relativity,
are produced by some of the most energetic and dramatic phenomena in the
cosmos, including black holes, neutron stars and supernovae. The detection of
gravitational waves will help to address a number of fundamental questions in
physics, from the evolution of stars and galaxies to the origin of dark energy
and the nature of space-time itself. Moreover, the cutting-edge technology
developed to search for gravitational waves is pushing back the frontiers of
many fields, from lasers and materials science to high performance computing,
and thus provides a powerful showcase for the attractions and challenges of a
career in science and engineering. For several years a worldwide network of
ground-based laser interferometric gravitational-wave detectors has been fully
operational, including the two LIGO detectors in the United States. These
detectors are already among the most sensitive scientific instruments on the
planet and in the next few years their sensitivity will achieve further
significant improvement. Those developments promise to open an exciting new
window on the Universe, heralding the arrival of gravitational-wave astronomy
as a revolutionary, new observational field. In this paper we describe the
extensive program of public outreach activities already undertaken by the LIGO
Scientific Collaboration, and a number of special events which we are planning
for IYA2009.


title:
Cross-concordances: terminology mapping and its effectiveness for
  information retrieval

abstract:
  The German Federal Ministry for Education and Research funded a major
terminology mapping initiative, which found its conclusion in 2007. The task of
this terminology mapping initiative was to organize, create and manage
'cross-concordances' between controlled vocabularies (thesauri, classification
systems, subject heading lists) centred around the social sciences but quickly
extending to other subject areas. 64 crosswalks with more than 500,000
relations were established. In the final phase of the project, a major
evaluation effort to test and measure the effectiveness of the vocabulary
mappings in an information system environment was conducted. The paper reports
on the cross-concordance work and evaluation results.


title: Chandra Confirmation of a Pulsar Wind Nebula in DA 495

abstract:
  As part of a multiwavelength study of the unusual radio supernova remnant DA
495, we present observations made with the Chandra X-ray Observatory. Imaging
and spectroscopic analysis confirms the previously detected X-ray source at the
heart of the annular radio nebula, establishing the radiative properties of two
key emission components: a soft unresolved source with a blackbody temperature
of 1 MK consistent with a neutron star, surrounded by a nonthermal nebula 40''
in diameter exhibiting a power-law spectrum with photon index Gamma =
1.6+/-0.3, typical of a pulsar wind nebula. The implied spin-down luminosity of
the neutron star, assuming a conversion efficiency to nebular flux appropriate
to Vela-like pulsars, is ~10^{35} ergs/s, again typical of objects a few tens
of kyr old. Morphologically, the nebular flux is slightly enhanced along a
direction, in projection on the sky, independently demonstrated to be of
significance in radio polarization observations; we argue that this represents
the orientation of the pulsar spin axis. At smaller scales, a narrow X-ray
feature is seen extending out 5'' from the point source, a distance consistent
with the sizes of resolved wind termination shocks around many Vela-like
pulsars. Finally, we argue based on synchrotron lifetimes in the estimated
nebular magnetic field that DA 495 represents a rare pulsar wind nebula in
which electromagnetic flux makes up a significant part, together with particle
flux, of the neutron star's wind, and that this high magnetization factor may
account for the nebula's low luminosity.


title: Dark Matter in the Solar System

abstract:
  We determine the density and mass distribution of dark matter within our
Solar System. We explore the three-body interactions between dark matter
particles, the Sun, and the planets to compute the amount of dark matter
gravitationally captured over the lifetime of the Solar System. We provide an
analytical framework for performing these calculations and detail our numerical
simulations accordingly. We find that the local density of dark matter is
enhanced by between three and five orders of magnitude over the background halo
density, dependent on the radial distance from the Sun. This has profound
implications for terrestrial direct dark matter detection searches. We also
discuss our results in the context of gravitational signatures, including
existing constraints, and find that dark matter captured in this fashion is not
responsible for the Pioneer anomaly. We conclude that dark matter appears to,
overall, play a much more important role in our Solar System than previously
thought.


title: A Null Test of the Metric Nature of the Cosmic Acceleration

abstract:
  We discuss the testable predictions of a phenomenological model in which the
accelerated expansion of the universe is the result of the action of a
non-gravitational force field, rather than the effect of a negative-pressure
dark-energy fluid or a modification of general relativity. We show, through the
equivalence principle, that in such a scenario the cosmic acceleration felt by
distant standard candles like SNIa depends on the mass of the host system,
being larger in galaxies than in rich clusters. As a consequence, the scatter
in the observed SNIa Hubble diagram has mostly a physical origin in this
scenario: in fact, the SNIa distance modulus is increasing, at fixed redshift,
for SNe that are hosted in isolated galaxies with respect to the case of SNe
hosted in rich galaxy clusters. Due to its strong dependence on the
astrophysical environments of standard candles, we conclude that alternative
non-gravitational mechanisms for the observed accelerated expansion of the
universe can be interestingly contrasted against the standard metric
interpretation of the cosmological acceleration by means of an environmental
analysis of the cosmic structures in which SNIa are found. The possible absence
of such environmental effects would definitely exclude non-gravitational
mechanisms as responsible for the accelerated cosmological expansion and will
therefore reinforce a metric interpretation.


title: Improved testing inference in mixed linear models

abstract:
  Mixed linear models are commonly used in repeated measures studies. They
account for the dependence amongst observations obtained from the same
experimental unit. Oftentimes, the number of observations is small, and it is
thus important to use inference strategies that incorporate small sample
corrections. In this paper, we develop modified versions of the likelihood
ratio test for fixed effects inference in mixed linear models. In particular,
we derive a Bartlett correction to such a test and also to a test obtained from
a modified profile likelihood function. Our results generalize those in Zucker
et al. (Journal of the Royal Statistical Society B, 2000, 62, 827-838) by
allowing the parameter of interest to be vector-valued. Additionally, our
Bartlett corrections allow for random effects nonlinear covariance matrix
structure. We report numerical evidence which shows that the proposed tests
display superior finite sample behavior relative to the standard likelihood
ratio test. An application is also presented and discussed.


title:
Combined density-functional and dynamical cluster quantum Monte Carlo
  calculations for three-band Hubbard models for hole-doped cuprate
  superconductors

abstract:
  Using a combined local density functional theory (LDA-DFT) and quantum Monte
Carlo (QMC) dynamic cluster approximation approach, the parameter dependence of
the superconducting transition temperature Tc of several single-layer
hole-doped cuprate superconductors with experimentally very different Tcmax is
investigated. The parameters of two different three-band Hubbard models are
obtained using the LDA and the downfolding Nth-order muffin-tin orbital
technique with N=0 and 1 respectively. QMC calculations on 4-site clusters show
that the d-wave transition temperature Tc depends sensitively on the
parameters. While the N=1 MTO basis set which reproduces all three $pd\sigma$
bands leads to a d-wave transition, the N=0 set which merely reproduces the LDA
Fermi surface and velocities does not.


title: Survey on geometric group theory

abstract:
  This article is a survey article on geometric group theory from the point of
view of a non-expert who likes geometric group theory and uses it in his own
research. The sections are: classical examples, basics about
quasiisometry,properties and invariants of groups invariant under
quasiisometry, rigidity, hyperbolic spaces and CAT(k)-spaces, the boundary of a
hyperbolic space, hyperbolic groups, CAT(0)-groups, classifying spaces for
proper actions, measurable group theory, some open problems.


title:
Emergence of mutationally robust proteins in a microscopic model of
  evolution

abstract:
  The ability to absorb mutations while retaining structure and function, or
mutational robustness, is a remarkable property of natural proteins. In this
Letter, we use a computational model of organismic evolution [Zeldovich et al,
PLOS Comp Biol 3(7):e139 (2007)], which explicitly couples protein physics and
population dynamics, to study mutational robustness of evolved model proteins.
We find that dominant protein structures which evolved in the simulations are
highly designable ones, in accord with some of the earlier observations. Next,
we compare evolved sequences with the ones designed to fold into the same
dominant structures and having the same thermodynamic stability, and find that
evolved sequences are more robust against point mutations, being less likely to
be destabilized upon them. These results point to sequence evolution as an
important method of protein engineering if mutational robustness of the
artificially developed proteins is desired. On the biological side, mutational
robustness of proteins appears to be a natural consequence of the
mutation-selection evolutionary process.