title:
Configuration Mixing within the Energy Density Functional Formalism:
  Removing Spurious Contributions from Non-Diagonal Energy Kernels

abstract:
  Multi-reference calculations along the lines of the Generator Coordinate
Method or the restoration of broken symmetries within the nuclear Energy
Density Functional (EDF) framework are becoming a standard tool in nuclear
structure physics. These calculations rely on the extension of a
single-reference energy functional, of the Gogny or the Skyrme types, to
non-diagonal energy kernels. There is no rigorous constructive framework for
this extension so far. The commonly accepted way proceeds by formal analogy
with the expressions obtained when applying the generalized Wick theorem to the
non-diagonal matrix element of a Hamilton operator between two product states.
It is pointed out that this procedure is ill-defined when extended to EDF
calculations as the generalized Wick theorem is taken outside of its range of
applicability. In particular, such a procedure is responsible for the
appearance of spurious divergences and steps in multi-reference EDF energies,
as was recently observed in calculations restoring particle number or angular
momentum. In the present work, we give a formal analysis of the origin of this
problem for calculations with and without pairing, i.e. constructing the
density matrices from either Slater determinants or quasi-particle vacua. We
propose a correction to energy kernels that removes the divergences and steps,
and which is applicable to calculations based on any symmetry restoration or
generator coordinate. The method is formally illustrated for particle number
restoration and is specified to configuration mixing calculations based on
Slater determinants.


title:
Obscured star formation in intermediate-density environments: A Spitzer
  study of the Abell 901/902 supercluster

abstract:
  We explore the amount of obscured star-formation as a function of environment
in the A901/902 supercluster at z=0.165 in conjunction with a field sample
drawn from the A901 and CDFS fields, imaged with HST as part of the STAGES and
GEMS surveys. We combine the COMBO-17 near-UV/optical SED with Spitzer 24um
photometry to estimate both the unobscured and obscured star formation in
galaxies with Mstar>10^{10}Msun. We find that the star formation activity in
massive galaxies is suppressed in dense environments, in agreement with
previous studies. Yet, nearly 40% of the star-forming galaxies have red optical
colors at intermediate and high densities. These red systems are not
starbursting; they have star formation rates per unit stellar mass similar to
or lower than blue star-forming galaxies. More than half of the red
star-forming galaxies have low IR-to-UV luminosity ratios, relatively high
Sersic indices and they are equally abundant at all densities. They might be
gradually quenching their star-formation, possibly but not necessarily under
the influence of gas-removing environmental processes. The other >40% of the
red star-forming galaxies have high IR-to-UV luminosity ratios, indicative of
high dust obscuration. They have relatively high specific star formation rates
and are more abundant at intermediate densities. Our results indicate that
while there is an overall suppression in the star-forming galaxy fraction with
density, the small amount of star formation surviving the cluster environment
is to a large extent obscured, suggesting that environmental interactions
trigger a phase of obscured star formation, before complete quenching.


title:
Can the study of reduction probabilities reveal news about the nature of
  quantum state reduction?

abstract:
  A phenomenological model for the calculation of reduction probabilities of a
superposition of several states is presented. The approach bases only the idea
that quantum state reduction has its origin in a mutual physical interaction
between the states. The model is explicitly worked out for the gravitational
reduction hypothesis of Diosi and Penrose. It agrees for typical quantum
mechanical experiments with the projection postulate and predicts regimes in
which other behavior could be observed. An outlook is given, how the new
effects can possibly become of interest for biology. For verification a
feasible quantum optical experiment is proposed. The approach is analyzed from
the view point of quantum non-locality in concrete its consequences for
signalling.


title: The Powers of Deconfinement

abstract:
  The trace anomaly of gluodynamics encodes the breakdown of classical scale
invariance due to interactions around the deconfinement phase transition. While
it is expected that at high temperatures perturbation theory becomes applicable
we show that current lattice calculations are far from the perturbative regime
and are dominated instead by inverse even power corrections in the temperature,
while the total perturbative contribution is estimated to be extremely small
and compatible with zero within error bars. We provide an interpretation in
terms of dimension-two gluon condensate of the dimensionally reduced theory
which value agrees with a similar analysis of power corrections from available
lattice data for the renormalized Polyakov loop and the heavy quark-antiquark
free energy in the deconfined phase of QCD.


title:
Particle-Number Restoration within the Energy Density Functional
  Formalism

abstract:
  We give a detailed analysis of the origin of spurious divergences and finite
steps that have been recently identified in particle-number restoration
calculations within the nuclear energy density functional framework. We isolate
two distinct levels of spurious contributions to the energy. The first one is
encoded in the definition of the basic energy density functional itself whereas
the second one relates to the canonical procedure followed to extend the use of
the energy density functional to multi-reference calculations. The first level
of spuriosity relates to the long-known self-interaction problem and to the
newly discussed self-pairing interaction process which might appear when
describing paired systems with energy functional methods using auxiliary
reference states of Bogoliubov or BCS type. A minimal correction to the second
level of spuriosity to the multi-reference nuclear energy density functional
proposed in [D. Lacroix, T. Duguet, M. Bender, arXiv:0809.2041] is shown to
remove completely the anomalies encountered in particle-number restored
calculations. In particular, it restores sum-rules over (positive) particle
numbers that are to be fulfilled by the particle-number-restored formalism. The
correction is found to be on the order of several hundreds of keVs up to about
1 MeV in realistic calculations, which is small compared to the total binding
energy, but often accounts for a substantial percentage of the energy gain from
particle-number restoration and is on the same energy scale as the excitations
one addresses with multi-reference energy density functional methods.


title:
Phase Diagram of the Attractive Hubbard Model with Inhomogeneous
  Interactions

abstract:
  The phase diagram of the attractive Hubbard model with spatially
inhomogeneous interactions is obtained using a single site dynamical mean field
theory like approach. The model is characterized by three parameters: the
interaction strength, the active fraction (fraction of sites with the
attractive interaction), and electron filling. The calculations indicate that
in a parameter regime with intermediate values of interaction strength
(compared to the bare bandwidth of the electrons), and intermediate values of
the active fraction, "non-BCS" superconductivity is obtained. The results of
this work are likely to be relevant to many systems with spatially
inhomogeneous superconductivity such as strongly correlated oxides, systems
with negative U centers, and, in future, cold atom optical lattices.


title: Reconstructing SUSY and R-Neutrino Masses in SO(10)

abstract:
  We report on the extrapolation of scalar mass parameters in the lepton sector
to reconstruct SO(10) scenarios close to the unification scale. The method is
demonstrated for an example in which SO(10) is broken directly to the Standard
Model, based on the expected precision from coherent LHC and ILC collider
analyses. In addition to the fundamental scalar mass parameters at the
unification scale, the mass of the heaviest right-handed neutrino can be
estimated in the seesaw scenario.


title:
Stability of higher dimensional Reissner-Nordstrom-anti-de Sitter black
  holes

abstract:
  We investigate stability of the D-dimensional
Reissner-Nordstrom-anti-de-Sitter metrics as solutions of the Einstein-Maxwell
equations. We have shown that asymptotically anti-de Sitter black holes are
dynamically stable for all values of charge and anti-de Sitter radius in
$D=5,6...11$ dimensional space-times. This does not contradict to dynamical
instability of RN-AdS black holes found by Gubser in $\mathcal{N}=8$ gauged
supergravity, because the latter instability comes from the tachyon mode of the
scalar field, coupled to the system. Asymptotically AdS black holes are known
to be thermodynamically unstable for some region of parameters, yet, as we have
shown here, they are stable against gravitational perturbations.


title:
Particle-Number Restoration within the Energy Density Functional
  formalism: Nonviability of terms depending on noninteger powers of the
  density matrices

abstract:
  We discuss the origin of pathological behaviors that have been recently
identified in particle-number-restoration calculations performed within the
nuclear energy density functional framework. A regularization method that
removes the problematic terms from the multi-reference energy density
functional and which applies (i) to any symmetry restoration- and/or
generator-coordinate-method-based configuration mixing calculation and (ii) to
energy density functionals depending only on integer powers of the density
matrices, was proposed in [D. Lacroix, T. Duguet, M. Bender, arXiv:0809.2041]
and implemented for particle-number restoration calculations in [M. Bender, T.
Duguet, D. Lacroix, arXiv:0809.2045]. In the present paper, we address the
viability of non-integer powers of the density matrices in the nuclear energy
density functional. Our discussion builds upon the analysis already carried out
in [J. Dobaczewski \emph{et al.}, Phys. Rev. C \textbf{76}, 054315 (2007)].
First, we propose to reduce the pathological nature of terms depending on a
non-integer power of the density matrices by regularizing the fraction that
relates to the integer part of the exponent using the method proposed in [D.
Lacroix, T. Duguet, M. Bender, arXiv:0809.2041]. Then, we discuss the spurious
features brought about by the remaining fractional power. Finally, we conclude
that non-integer powers of the density matrices are not viable and should be
avoided in the first place when constructing nuclear energy density functionals
that are eventually meant to be used in multi-reference calculations.


title:
Factorization of R-matrix and Baxter Q-operators for generic sl(N) spin
  chains

abstract:
  We develop an approach for constructing the Baxter Q-operators for generic
sl(N) spin chains. The key element of our approach is the possibility to
represent a solution of the the Yang Baxter equation in the factorized form. We
prove that such a representation holds for a generic sl(N) invariant R-operator
and find the explicit expression for the factorizing operators. Taking trace of
monodromy matrices constructed of the factorizing operators one defines a
family of commuting (Baxter) operators on the quantum space of the model. We
show that a generic transfer matrix factorizes into the product of N Baxter
Q-operators and discuss an application of this representation for a derivation
of functional relations for transfer matrices.


title: Cometary Astropause of Mira Revealed in the Far-Infrared

abstract:
  Evolved mass-losing stars such as Mira enrich the interstellar medium (ISM)
significantly by their dust-rich molecular wind. When these stars move fast
enough relative to the ISM, the interaction between the wind and ISM generates
the structure known as the astropause (a stellar analog of the heliopause),
which is a cometary stellar wind cavity bounded by the contact discontinuity
surface between the wind and ISM. Far-infrared observations of Mira spatially
resolve the structure of its astropause for the first time, distinguishing the
contact surface between Mira's wind and the ISM and the termination shock due
to Mira's wind colliding with the ISM. The physical size of the astropause and
the estimated speed of the termination shock suggest the age of the astropause
to be about 40,000 yr, confirming a theoretical prediction of the shock
re-establishment time after Mira has entered the Local Bubble.


title:
Exact Series Reconstruction in Photoacoustic Tomography with Circular
  Integrating Detectors

abstract:
  A method for photoacoustic tomography is presented that uses circular
integrals of the acoustic wave for the reconstruction of a three-dimensional
image. Image reconstruction is a two-step process: In the first step data from
a stack of circular integrating are used to reconstruct the circular projection
of the source distribution. In the second step the inverse circular Radon
transform is applied. In this article we establish inversion formulas for the
first step, which involves an inverse problem for the axially symmetric wave
equation. Numerical results are presented that show the validity and robustness
of the resulting algorithm.


title:
Extended Palatini action for general relativity and the natural
  emergence of the cosmological constant

abstract:
  In the Palatini action of general relativity the connection and the metric
are treated as independent dynamical variables. Instead of assuming a relation
between these quantities, the desired relation between them is derived through
the Euler-Lagrange equations of the Palatini action. In this manuscript we
construct an extended Palatini action, where we do not assume any a priori
relationship between the connection, the covariant metric tensor, and the
contravariant metric tensor. Instead we treat these three quantities as
independent dynamical variables. We show that this action reproduces the
standard Einstein field equations depending on a single metric tensor. We
further show that in this formulation the cosmological constant has an
additional theoretical significance. Normally the cosmological constant is
added to the Einstein field equations for the purpose of having general
relativity be consistent with cosmological observations. In the formulation
presented here, the nonvanishing cosmological constant also ensures the
self-consistency of the theory.


title:
Pressure-induced shift of T$_c$ in K$_x$Sr$_{1-x}$Fe$_2$As$_2$ (x=0.2,
  0.4, 0.7): Analogy to the high-T$_c$ cuprate superconductors

abstract:
  The systematic pressure shifts of T_c were investigated in the whole phase
diagram of the FeAs-based superconducting compound K_xSr_{1-x}Fe_2As_2.
Different regions, arising from corresponding responses of T$_c$ to pressure
(dT_c/dp>0, =0, or <0), can be clearly distinguished. This reveals an
interesting similarity of the FeAs superconductors and the high-T_c cuprates.
This behavior is a manifestation of the layered structure of the FeAs compounds
and the pressure-induced charge transfer between the (Fe_2As_2) and (K/Sr)
layers. The coexistence of superconductivity and spin-density wave behavior
were also observed, and the pressure effects on the latter is explored.


title: Classification of qubit entanglement: SL(2,C) versus SU(2) invariance

abstract:
  The role of SU(2) invariants for the classification of multiparty
entanglement is discussed and exemplified for the Kempe invariant I_5 of pure
three-qubit states. It is found to being an independent invariant only in
presence of both W-type entanglement and threetangle. In this case, constant
I_5 admits for a wide range of both threetangle and concurrences. Furthermore,
the present analysis indicates that an SL^3 orbit of states with equal tangles
but continuously varying I_5 must exist. This means that I_5 provides no
information on the entanglement in the system in addition to that contained in
the tangles (concurrences and threetangle) themselves. Together with the
numerical evidence that I_5 is an entanglement monotone this implies that SU(2)
invariance or the monotone property are too weak requirements for the
characterization and quantification of entanglement for systems of three
qubits, and that SL(2,C) invariance is required. This conclusion can be
extended to general multipartite systems (including higher local dimension)
because the entanglement classes of three-qubit systems appear as subclasses.


title: A Study of Hadron Deformation in Lattice QCD

abstract:
  We develop the formalism for the evaluation of density-density correlators in
lattice QCD that includes techniques for the computation of the all-to-all
propagators involved. A novel technique in this context is the implementation
of the one-end trick in the meson sector. Density-density correlators provide a
gauge invariant definition for the hadron wave function and yield information
on hadron deformation. We evaluate density-density correlators using two
degenerate flavors of dynamical Wilson fermions for the pion, the rho-meson,
the nucleon and the $\Delta$. Using the one-end trick we obtain results that
clearly show deformation of the rho-meson.


title: Smooth solutions of quasianalytic or ultraholomorphic equations

abstract:
  In the first part of this work, we consider a polynomial $
\phi(x,y)=y^d+a_1(x)y^{d-1}+...+a_d(x) $ whose coefficients $ a_j $ belong to a
Denjoy-Carleman quasianalytic local ring $ \mathcal{E}_1(M) $. Assuming that $
\mathcal{E}_1(M) $ is stable under derivation, we show that if $ h $ is a germ
of $ C^\infty $ function such that $ \phi(x,h(x))=0 $, then $ h $ belongs to $
\mathcal{E}_1(M) $. This extends a well-known fact about real-analytic
functions. We also show that the result fails in general for non-quasianalytic
ultradifferentiable local rings. In the second part of the paper, we study a
similar problem in the framework of ultraholomorphic functions on sectors of
the Riemann surface of the logarithm. We obtain a result that includes suitable
non-quasianalytic situations.


title:
Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor
  systems

abstract:
  Magnetic spin fluctuations is one candidate to produce the bosonic modes that
mediate the superconductivity in the ferrous superconductors. Up until now, all
of the LaOFeAs and BaFe2As2 structure types have simple commensurate magnetic
ground states, as result of nesting Fermi surfaces. This type of
spin-density-wave (SDW) magnetic order is known to be vulnerable to shifts in
the Fermi surface when electronic densities are altered at the superconducting
compositions. Superconductivity has more recently been discovered in
alpha-Fe(Te,Se), whose electronically active antifluorite planes are
isostructural to the FeAs layers found in the previous ferrous superconductors
and share with them the same quasi-two-dimensional electronic structure. Here
we report neutron scattering studies that reveal a unique complex
incommensurate antiferromagnetic order in the parent compound alpha-FeTe. When
the long-range magnetic order is suppressed by the isovalent substitution of Te
with Se, short-range correlations survive in the superconducting phase.


title:
Existence and uniqueness of traveling waves in a class of unidirectional
  lattice differential equations

abstract:
  We prove the existence and uniqueness, for wave speeds sufficiently large, of
monotone traveling wave solutions connecting stable to unstable spatial
equilibria for a class of $N$-dimensional lattice differential equations with
unidirectional coupling. This class of lattice equations includes some spatial
discretizations for hyperbolic conservation laws with a source term as well as
a subclass of monotone systems. We obtain a variational characterization of the
critical wave speed above which monotone traveling wave solutions are
guaranteed to exist. We also discuss non-monotone waves, and the coexistence of
monotone and non-monotone waves.


title:
Laser frequency combs and ultracold neutrons to probe braneworlds
  through induced matter swapping between branes

abstract:
  This paper investigates a new experimental framework to test the braneworld
hypothesis. Recent theoretical results have shown the possibility of matter
exchange between branes under the influence of suitable magnetic vector
potentials. It is shown that the required conditions might be achieved with
present-day technology. The experiment uses a source of pulsed and coherent
electromagnetic radiation and relies on the Hansch frequency comb technique
well-known in ultrahigh-precision spectroscopy. A good matter candidate for
testing the hypothesis is a polarized ultracold neutron gas for which the
number of swapped neutrons is measured.


title: Weyl's Predicative Classical Mathematics as a Logic-Enriched Type Theory

abstract:
  We construct a logic-enriched type theory LTTW that corresponds closely to
the predicative system of foundations presented by Hermann Weyl in Das
Kontinuum. We formalise many results from that book in LTTW, including Weyl's
definition of the cardinality of a set and several results from real analysis,
using the proof assistant Plastic that implements the logical framework LF.
This case study shows how type theory can be used to represent a
non-constructive foundation for mathematics.


title: Static quark anti-quark pair in SU(2) gauge theory

abstract:
  We study singlet and triplet correlation functions of static quark anti-quark
pair defined through gauge invariant time-like Wilson loops and Polyakov loop
correlators in finite temperature SU(2) gauge theory. We use the Luescher-Weisz
multilevel algorithm, which allows to calculate these correlators at very low
temperatures. We observe that the naive separation of singlet and triplet
states in general does not hold non-perturbatively, however, is recovered in
the limit of small separation and the temperature dependence of the
corresponding correlators is indeed very different.


title: Statistical physics of dyons and quark confinement

abstract:
  We present a semiclassical approach to the SU(N) Yang--Mills theory whose
partition function at nonzero temperatures is approximated by a saddle point --
an ensemble of an infinite number of interacting dyons of N kinds. The ensemble
is governed by an exactly solvable 3d quantum field theory, allowing
calculation of correlations functions relevant to confinement. We show that
known criteria of confinement are satisfied in this semiclassical
approximation: (i) the average Polyakov line is zero below some critical
temperature, and nonzero above it, (ii) a quark-antiquark pair has linear
rising potential energy, (iii) the average spatial Wilson loop falls off
exponentially with the area, (iv) N^2 gluons are canceled out from the
spectrum, (v) the critical deconfinement temperature is in good agreement with
lattice data. Using the same approximation, we find confinement for the
exceptional gauge group G(2) and a first-order deconfinement transition, also
in agreement with lattice findings.


title: Large-N Summation of Chiral Logs for Generalized Parton Distributions

abstract:
  We demonstrate that in the region of Bjorken x ~m_\pi^2/(4\pi F_\pi)^2 and/or
x ~|t|/(4\pi F_\pi)^2 the standard ChPT for the pion GPDs fails and one must
perform all order resummation of ChPT. We perform such resummation in the
large-N limit of the O(N+1) extension of the chiral theory. Explicit
resummation allows us to reveal novel phenomena -- the form of the leading
chiral correction to pion PDFs and GPDs depends on the small-x asymptotic of
the pion PDFs. In particular, if the pion PDF in the chiral limit has the
Regge-like small x behaviour q(x)~1/x^\omega, the leading large impact
parameter ($b_\perp\to\infty$) asymptotics of the quark distribution in the
transverse plane has the form ($m_\pi=0$) $q(x,b_\perp)\sim 1/x^\omega\
\ln^{\omega}(b_\perp^2)/b_\perp^{2{(1+\omega)}}$. This result is model
independent and it is controlled completely by the all order resummed ChPT
developed in this paper. This asymptotic interweaves with small-$x$ behaviour
of usual PDFs, hence it depends on the scale, at which the corresponding PDF is
defined. This is a new and interesting result in which the chiral expansion
meets the QCD evolution.


title: Schmidt's game, Badly Approximable Linear Forms and Fractals

abstract:
  We prove that for every two natural numbers M and N, if Tau is a Borel,
finite, absolutely friendly measure on a compact set K of R^MN, then the
intersection of K and BA(M,N) is a winning set in Schmidt's game sense played
on K, where BA(M,N) is the set of badly approximable M\times N matrices. As an
immediate consequence we have the following application. If K is the attractor
of an irreducible finite family of contracting similarity maps of R^(M\times N)
satisfying the open set condition, (the Cantor ternary set, Koch's curve and
Sierpinski's gasket to name a few examples), the dimK=dimK\capBA(M,N).


title: Calibration update of the COMBO-17 CDFS catalogue

abstract:
  We present an update to the photometric calibration of the COMBO-17 catalogue
on the Extended Chandra Deep Field South, which is now consistent with the
GaBoDS and MUSYC catalogues. As a result, photometric redshifts become slightly
more accurate, with <0.01 rms and little bias in the delta_z/(1+z) of galaxies
with R<21 and of QSOs with R<24. With increasing photon noise the rms of
galaxies reaches 0.02 for R<23 and 0.035 at R~23.5. Consequences for the
rest-frame colours of galaxies at z<1 are discussed.


title: Indirect Signatures of Gravitino Dark Matter

abstract:
  Supersymmetric models provide very interesting scenarios to account for the
dark matter of the Universe. In this talk we discuss scenarios with gravitino
dark matter in R-parity breaking vacua, which not only reproduce very naturally
the observed dark matter relic density, but also lead to a thermal history of
the Universe consistent with the observed abundances of primordial elements and
the observed matter-antimatter asymmetry. In this class of scenarios the dark
matter gravitinos are no longer stable, but decay with very long lifetimes into
Standard Model particles, thus opening the possibility of their indirect
detection. We have computed the expected contribution from gravitino decay to
the primary cosmic rays and we have found that a gravitino with a mass of 150
GeV and a lifetime of 10^26 s could simultaneously explain the EGRET anomaly in
the extragalactic gamma-ray background and the HEAT excess in the positron
fraction.


title: On the finite generation of a family of Ext modules

abstract:
  Let $Q$ be a Noetherian ring with finite Krull dimension and let $\mathbf{f}=
f_1,... f_c$ be a regular sequence in $Q$. Set $A = Q/(\mathbf{f})$. Let $I$ be
an ideal in $A$, and let $M$ be a finitely generated $A$-module with
$\projdim_Q M$ finite. Set $\R = \bigoplus_{n\geq 0}I^n$, the Rees-Algebra of
$I$. Let $N = \bigoplus_{j \geq 0}N_j$ be a finitely generated graded
$\R$-module.
  We show that \[\bigoplus_{j\geq 0}\bigoplus_{i\geq 0} \Ext^{i}_{A}(M,N_j) \]
is a finitely generated bi-graded module over $\Sc = \R[t_1,...,t_c]$. We give
two applications of this result to local complete intersection rings.


title: The determination of the apsidal angles and Bertrand's theorem

abstract:
  We derive an expression for the determination of the apsidal angles that
holds good for arbitrary central potentials. Then we discuss under what
conditions the apsidal angles remain independent of the mechanical energy and
angular momentum in the central force problem. As a consequence, an alternative
and non-perturbative proof of Bertrand's theorem is obtained.


title: Comparing operadic theories of $n$-category

abstract:
  We give a framework for comparing on the one hand theories of n-categories
that are weakly enriched operadically, and on the other hand n-categories given
as algebras for a contractible globular operad. Examples of the former are the
definition by Trimble and variants (Cheng-Gurski) and examples of the latter
are the definition by Batanin and variants (Leinster). We will show how to take
a theory of n-categories of the former kind and produce a globular operad whose
algebras are the n-categories we started with. We first provide a
generalisation of Trimble's original theory that allows for the use of other
parametrising operads in a very general way, via the notion of categories
weakly enriched in V where the weakness is parametrised by an operad P in the
category V. We define weak n-categories by iterating the weak enrichment
construction using a series of parametrising operads P_i. We then show how to
construct from such a theory an n-dimensional globular operad for each $n \geq
0$ whose algebras are precisely the n-categories we constructed by iterated
weak enrichment, and we show that the resulting globular operad is contractible
precisely when the operads P_i are contractible. We then show how the globular
operad associated with Trimble's topological definition is related to the
globular operad used by Batanin to define fundamental n-groupoids of spaces.


title: Super Marx Generator for Thermonuclear Ignition

abstract:
  In ongoing electric pulse power driven inertial confinement fusion
experiments, Marx generators are connected in parallel with the target in the
center of a ring of the Marx generators. There the currents, not the voltages
add up. Instead of connecting a bank of Marx generator in parallel, one may
connect them in series, adding up their voltages, not the currents. If, for
example, fifty 20 MV Marx generators are connected in series, they would add up
to a gigavolt. But to prevent breakdown, the adding up of the voltages in such
a super-Marx generator must be fast. For this reason, it is proposed that each
of the Marx generators charges up a fast discharge capacitor, with the thusly
charged fast capacitors becoming the elements of a second stage super Marx
generator. In a super Marx generator, the Marx generators also assume the role
of the resistors in the original Marx circuit.
  With a voltage of 10^9 Volt and a discharge current of 10^7 Ampere, the
generation of a 10^16 Watt GeV proton beam becomes possible, which can ignite
in liquid deuterium a thermonuclear micro-detonation.


title:
Error estimates for Raviart-Thomas interpolation of any order on
  anisotropic tetrahedra

abstract:
  We prove optimal order error estimates for the Raviart-Thomas interpolation
of arbitrary order under the maximum angle condition for triangles and under
two generalizations of this condition, namely, the so-called three dimensional
maximum angle condition and the regular vertex property, for tetrahedra.
  Our techniques are different from those used in previous papers on the
subject and the results obtained are more general in several aspects. First,
intermediate regularity is allowed, that is, for the Raviart-Thomas
interpolation of degree $k\ge 0$, we prove error estimates of order $j+1$ when
the vector field being approximated has components in $W^{j+1,p}$, for
triangles or tetrahedra, where $0\le j \le k$ and $1\le p \le\infty$. These
results are new even in the two dimensional case. Indeed, the estimate was
known only in the case $j=k$. On the other hand, in the three dimensional case,
results under the maximum angle condition were known only for $k=0$.


title: A Multi-Epoch HST Study of the Herbig-Haro Flow from XZ Tauri

abstract:
  We present nine epochs of Hubble Space Telescope optical imaging of the
bipolar outflow from the pre-main sequence binary XZ Tauri. Our data monitors
the system from 1995-2005 and includes emission line images of the flow. The
northern lobe appears to be a succession of bubbles, the outermost of which
expanded ballistically from 1995-1999 but in 2000 began to deform and
decelerate along its forward edge. It reached an extent of 6" from the binary
in 2005. A larger and fainter southern counterbubble was detected for the first
time in deep ACS images from 2004. Traces of shocked emission are seen as far
as 20" south of the binary. The bubble emission nebulosity has a low excitation
overall, as traced by the [S II]/H-alpha line ratio, requiring a nearly
comoving surrounding medium that has been accelerated by previous ejections or
stellar winds.
  Within the broad bubbles there are compact emission knots whose alignments
and proper motions indicate that collimated jets are ejected from each binary
component. The jet from the southern component, XZ Tau A, is aligned with the
outflow axis of the bubbles and has tangential knot velocities of 70-200 km/s.
Knots in the northern flow are seen to slow and brighten as they approach the
forward edge of the outermost bubble. The knots in the jet from the other star,
XZ Tau B, have lower velocities of ~100 km/s.


title:
Character Average of Second and Fourth Powers of Dirichlet L-Series at
  Unity

abstract:
  We obtain by simple elementary method, the character average of fourth power
of Dirichlet L-series at unity.This result seems to be new.We also obtain
character average of second power of Dirichlet L-series at unity,using the
power series in second variable of Hurwitz zeta function at unity.


title:
Low congestion online routing and an improved mistake bound for online
  prediction of graph labeling

abstract:
  In this paper, we show a connection between a certain online low-congestion
routing problem and an online prediction of graph labeling. More specifically,
we prove that if there exists a routing scheme that guarantees a congestion of
$\alpha$ on any edge, there exists an online prediction algorithm with mistake
bound $\alpha$ times the cut size, which is the size of the cut induced by the
label partitioning of graph vertices. With previous known bound of $O(\log n)$
for $\alpha$ for the routing problem on trees with $n$ vertices, we obtain an
improved prediction algorithm for graphs with high effective resistance.
  In contrast to previous approaches that move the graph problem into problems
in vector space using graph Laplacian and rely on the analysis of the
perceptron algorithm, our proof are purely combinatorial. Further more, our
approach directly generalizes to the case where labels are not binary.


title: Evolution of the Radio Loud Galaxy Population

abstract:
  A catalogue of 14453 radio-loud AGN with 1.4 GHz fluxes above 3.5 mJy in the
redshift range 0.4<z<0.8, has been constructed from the cross-correlation of
the NVSS and FIRST radio surveys with the MegaZ-LRG catalogue of luminous red
galaxies derived from Sloan Digital Sky Survey imaging data. New techniques
were developed for extending the cross-correlation algorithm to FIRST
detections that are below the nominal 1 mJy S/N limit of the catalogued
sources. We estimate a reliability of ~98.3%, and completeness level (for LRGS)
of about 95% for our new catalogue. We present a new determination of the
luminosity function of radio AGN at z~0.55 and compare this to the luminosity
function of nearby (z~0.1) radio sources from the SDSS main survey. The
comoving number density of radio AGN with luminosities less than 10^{25} W
Hz^{-1} increases by a factor ~1.5 between z=0.1 and z=0.55. At higher
lumiosities, this factor increases sharply, reaching values of more than 10 at
radio luminosities larger than 10^{26} W Hz^{-1}. We then study how the
relation between radio AGN and their host galaxies evolves with redshift. Our
main conclusion is that the fraction of radio-loud AGN increases towards higher
redshift in all massive galaxies, but the evolution is particularly strong for
the lower mass galaxies in our sample. These trends may be understood if there
are two classes of radio galaxies (likely associated with the "radio" and
"quasar mode" dichotomy) that have different fuelling/triggering mechanisms and
hence evolve in different ways.


title:
Coupling Nonlinear Sigma-Matter to Yang-Mills Fields: Symmetry Breaking
  Patterns

abstract:
  We extend the traditional formulation of Gauge Field Theory by incorporating
the (non-Abelian) gauge group parameters (traditionally simple spectators) as
new dynamical (nonlinear-sigma-model-type) fields. These new fields interact
with the usual Yang-Mills fields through a generalized minimal coupling
prescription, which resembles the so-called Stueckelberg transformation, but
for the non-Abelian case. Here we study the case of internal gauge symmetry
groups, in particular, unitary groups U(N). We show how to couple standard
Yang-Mills Theory to Nonlinear-Sigma Models on cosets of U(N): complex
projective, Grassman and flag manifolds. These different couplings lead to
distinct (chiral) symmetry breaking patterns and \emph{Higgs-less}
mass-generating mechanisms for Yang-Mills fields.


title:
Commensurability and hysteretic evolution of vortex configurations in
  rotating optical lattices

abstract:
  We present a theoretical study of vortices within a harmonically trapped
Bose-Einstein condensate in a rotating optical lattice. Due to the competition
between vortex-vortex interactions and pinning to the optical lattice we find a
very complicated energy landscape, which leads to hysteretic evolution. The
qualitative structure of the vortex configurations depends on the
commensurability between the vortex density and the site density -- with
regular lattices when these are commensurate, and concentric rings when they
are not. We model the imaging of these structures by calculating time-of-flight
column densities. As in the absence of the optical lattice, the vortices are
much more easily observed in a time-of-flight image than \emph{in-situ}.


title: Protein Folding: A New Geometric Analysis

abstract:
  A geometric analysis of protein folding, which complements many of the models
in the literature, is presented. We examine the process from unfolded strand to
the point where the strand becomes self-interacting. A central question is how
it is possible that so many initial configurations proceed to fold to a unique
final configuration. We put energy and dynamical considerations temporarily
aside and focus upon the geometry alone. We parameterize the structure of an
idealized protein using the concept of a ribbon from differential geometry. The
deformation of the ribbon is described by introducing a generic twisting
Ansatz. The folding process in this picture entails a change in shape guided by
the local amino acid geometry. The theory is reparamaterization invariant from
the start, so the final shape is independent of folding time. We develop
differential equations for the changing shape. For some parameter ranges, a
sine-Gordon torsion soliton is found. This purely geometric waveform has
properties similar to dynamical solitons. Namely: A threshold distortion of the
molecule is required to initiate the soliton, after which, small additional
distortions do not change the waveform. In this analysis, the soliton twists
the molecule until bonds form. The analysis reveals a quantitative relationship
between the geometry of the amino acids and the folded form.

categories: math-ph math.DG math.MP physics.bio-ph physics.chem-ph q-bio.BM


title:
Transient terahertz spectroscopy of excitons and unbound carriers in
  quasi two-dimensional electron-hole gases

abstract:
  We report a comprehensive experimental study and detailed model analysis of
the terahertz dielectric response and density kinetics of excitons and unbound
electron-hole pairs in GaAs quantum wells. A compact expression is given, in
absolute units, for the complex-valued terahertz dielectric function of
intra-excitonic transitions between the 1s and higher-energy exciton and
continuum levels. It closely describes the terahertz spectra of resonantly
generated excitons. Exciton ionization and formation are further explored,
where the terahertz response exhibits both intra-excitonic and Drude features.
Utilizing a two-component dielectric function, we derive the underlying exciton
and unbound pair densities. In the ionized state, excellent agreement is found
with the Saha thermodynamic equilibrium, which provides experimental
verification of the two-component analysis and density scaling. During exciton
formation, in turn, the pair kinetics is quantitatively described by a Saha
equilibrium that follows the carrier cooling dynamics. The terahertz-derived
kinetics is, moreover, consistent with time-resolved luminescence measured for
comparison. Our study establishes a basis for tracking pair densities via
transient terahertz spectroscopy of photoexcited quasi-two-dimensional
electron-hole gases.


title: Singularities of Affine Schubert Varieties

abstract:
  This paper studies the singularities of affine Schubert varieties in the
affine Grassmannian (of type $\mathrm{A}^{(1)}_\ell$). For two classes of
affine Schubert varieties, we determine the singular loci; and for one class,
we also determine explicitly the tangent spaces at singular points. For a
general affine Schubert variety, we give partial results on the singular locus.


title: Some remarks on Betti numbers of random polygon spaces

abstract:
  Polygon spaces like $M_\ell=\{(u_1,...,u_n)\in S^1\times... S^1 ;\
\sum_{i=1}^n l_iu_i=0\}/SO(2)$ or they three dimensional analogues $N_\ell$
play an important r\^ole in geometry and topology, and are also of interest in
robotics where the $l_i$ model the lengths of robot arms. When $n$ is large,
one can assume that each $l_i$ is a positive real valued random variable,
leading to a random manifold. The complexity of such manifolds can be
approached by computing Betti numbers, the Euler characteristics, or the
related Poincar\'e polynomial. We study the average values of Betti numbers of
dimension $p_n$ when $p_n\to\infty$ as $n\to\infty$. We also focus on the
limiting mean Poincar\'e polynomial, in two and three dimensions. We show that
in two dimensions, the mean total Betti number behaves as the total Betti
number associated with the equilateral manifold where $l_i\equiv \bar l$. In
three dimensions, these two quantities are not any more asymptotically
equivalent. We also provide asymptotics for the Poincar\'e polynomials


title: How to Integrate a Polynomial over a Simplex

abstract:
  This paper settles the computational complexity of the problem of integrating
a polynomial function f over a rational simplex. We prove that the problem is
NP-hard for arbitrary polynomials via a generalization of a theorem of Motzkin
and Straus. On the other hand, if the polynomial depends only on a fixed number
of variables, while its degree and the dimension of the simplex are allowed to
vary, we prove that integration can be done in polynomial time. As a
consequence, for polynomials of fixed total degree, there is a polynomial time
algorithm as well. We conclude the article with extensions to other polytopes,
discussion of other available methods and experimental results.


title: Compressible Sherrington-Kirkpatrick spin-glass model

abstract:
  We introduce a Sherrington-Kirkpatrick spin-glass model with the addition of
elastic degrees of freedom. The problem is formulated in terms of an effective
four-spin Hamiltonian in the pressure ensemble, which can be treated by the
replica method. In the replica-symmetric approximation, we analyze the
pressure-temperature phase diagram, and obtain expressions for the critical
boundaries between the disordered and the ordered (spin-glass and
ferromagnetic) phases. The second-order para-ferromagnetic border ends at a
tricritical point, beyond which the transition becomes discontinuous. We use
these results to make contact with the temperature-concentration phase diagrams
of mixtures of hydrogen-bonded crystals.


title: Clustered Multi-Task Learning: A Convex Formulation

abstract:
  In multi-task learning several related tasks are considered simultaneously,
with the hope that by an appropriate sharing of information across tasks, each
task may benefit from the others. In the context of learning linear functions
for supervised classification or regression, this can be achieved by including
a priori information about the weight vectors associated with the tasks, and
how they are expected to be related to each other. In this paper, we assume
that tasks are clustered into groups, which are unknown beforehand, and that
tasks within a group have similar weight vectors. We design a new spectral norm
that encodes this a priori assumption, without the prior knowledge of the
partition of tasks into groups, resulting in a new convex optimization
formulation for multi-task learning. We show in simulations on synthetic
examples and on the IEDB MHC-I binding dataset, that our approach outperforms
well-known convex methods for multi-task learning, as well as related non
convex methods dedicated to the same problem.


title: Wahl's conjecture for a minuscule G/P

abstract:
  We show that Wahl's conjecture holds in all characteristics for a minuscule
G/P.


title:
The Galactic potential and the asymmetric distribution of hypervelocity
  stars

abstract:
  In recent years several hypervelocity stars (HVSs) have been observed in the
halo of our Galaxy. Such HVSs have possibly been ejected from the Galactic
center and then propagated in the Galactic potential up to their current
position. The recent survey for candidate HVSs show an asymmetry in the
kinematics of candidate HVSs (position and velocity vectors), where more
outgoing stars than ingoing stars (i.e. positive Galactocentric velocities vs.
negative ones) are observed. We show that such kinematic asymmetry, which is
likely due to the finite lifetime of the stars and Galactic potential
structure, could be used in a novel method to probe and constrain the Galactic
potential, identify the stellar type of the stars in the survey and estimate
the number of HVSs. Kinematics-independent identification of the stellar types
of the stars in such surveys (e.g. spectroscopic identification) could further
improve these results. We find that the observed asymmetry between ingoing and
outgoing stars favors specific Galactic potential models. It also implies a
lower limit of ~54+-8 main sequence HVSs in the survey sample (>=648+-96 in the
Galaxy), assuming that all of the main sequence stars in the survey originate
from the Galactic center. The other stars in the survey are likely to be hot
blue horizontal branch stars born in the halo rather than stars ejected from
the Galactic center.


title:
Mapping the Dark Side with DEIMOS: Globular Clusters, X-ray Gas, and
  Dark Matter in the NGC 1407 Group

abstract:
  NGC 1407 is the central elliptical in a nearby evolved galaxy group
apparently destined to become a cluster core. We use the kinematics of globular
clusters to probe the dynamics and mass profile of the group's center, out to
60 kpc (~10 R_eff) -- the most extended data set to date around an early-type
galaxy. This sample consists of 172 GC velocities, most of them newly obtained
using Keck/DEIMOS, with a few additional objects identified as DGTOs or as
IGCs. We find weak rotation in the GC system's outer parts, with the metal-poor
and metal-rich GCs misaligned. The RMS velocity profile declines rapidly to a
radius of ~20 kpc, and then becomes flat or rising to ~60 kpc. There is
evidence that the GC orbits have a tangential bias that is strongest for the
metal-poor GCs -- possibly contradicting theoretical expectations. We construct
cosmologically-motivated galaxy+dark halo dynamical models and infer a mass
within 60 kpc of ~3x10^12 M_Sun, extrapolating to a virial mass of ~6x10^13
M_Sun for a typical LCDM halo -- in agreement with results from group galaxy
kinematics. We present an independent Chandra-based analysis, whose relatively
high mass at ~20 kpc disagrees strongly with the GC-based result unless the GCs
are assumed to have a peculiar orbit distribution, and we discuss some general
comparisons between X-ray and optical results. The group's B-band mass-to-light
ratio of ~800 is extreme even for a rich galaxy cluster, much less a poor group
-- placing it among the most dark matter dominated systems in the universe, and
also suggesting a massive reservoir of baryons lurking in an unseen phase, in
addition to the nonbaryonic dark matter. We compare the kinematical and mass
properties of the NGC 1407 group to other nearby groups and clusters, and
discuss some implications of this system for structure formation.


title:
Atmospheric circulation of hot Jupiters: Coupled radiative-dynamical
  general circulation model simulations of HD 189733b and HD 209458b

abstract:
  We present global, three-dimensional numerical simulations of HD 189733b and
HD 209458b that couple the atmospheric dynamics to a realistic representation
of non-gray cloud-free radiative transfer. The model, which we call the
Substellar and Planetary Atmospheric Radiation and Circulation (SPARC) model,
adopts the MITgcm for the dynamics and uses the radiative model of McKay,
Marley, Fortney, and collaborators for the radiation. Like earlier work with
simplified forcing, our simulations develop a broad eastward equatorial jet,
mean westward flow at higher latitudes, and substantial flow over the poles at
low pressure. For HD 189733b, our simulations without TiO and VO opacity can
explain the broad features of the observed 8 and 24-micron light curves,
including the modest day-night flux variation and the fact that the planet/star
flux ratio peaks before the secondary eclipse. Our simulations also provide
reasonable matches to the Spitzer secondary-eclipse depths at 4.5, 5.8, 8, 16,
and 24 microns and the groundbased upper limit at 2.2 microns. However, we
substantially underpredict the 3.6-micron secondary-eclipse depth, suggesting
that our simulations are too cold in the 0.1-1 bar region. Predicted temporal
variability in secondary-eclipse depths is ~1% at Spitzer bandpasses,
consistent with recent observational upper limits at 8 microns. We also show
that nonsynchronous rotation can significantly alter the jet structure. For HD
209458b, we include TiO and VO opacity; these simulations develop a hot (>2000
K) dayside stratosphere. Despite this stratosphere, we do not reproduce current
Spitzer photometry of this planet. Light curves in Spitzer bandpasses show
modest phase variation and satisfy the observational upper limit on day-night
phase variation at 8 microns. (abridged)


title: Suzaku Observations of Local Ultraluminous Infrared Galaxies

abstract:
  We report the results from our analysis of {\it Suzaku} XIS (0.5-10 keV) and
HXD/PIN (15-40 keV) observations of five well-known local ULIRGs: {\em IRAS}
F05189-2524, {\em IRAS} F08572+3915, Mrk 273, PKS 1345+12, and Arp 220. The XIS
observations of F05189-2524 and Mrk 273 reveal strong iron lines consistent
with Fe K$\alpha$ and changes in spectral shapes with respect to previous {\it
Chandra} and {\it XMM-Newton} observations. Mrk 273 is also detected by the
HXD/PIN at $\sim$1.8-$\sigma$. For F05189-2524, modeling of the data from the
different epochs suggests that the change in spectral shape is likely due to
the central source switching off, leaving behind a residual reflection
spectrum, or an increase in the absorbing column. An increase in the covering
fraction of the absorber can describe the spectral variations seen in Mrk 273,
although a reduction in the intrinsic AGN luminosity cannot be formally ruled
out. The {\it Suzaku} spectra of Mrk 273 are well fit by a ~94% covering
fraction model with a column density of $\sim10^{24}$ cm$^{-2}$. The
absorption-corrected log[$L_{\rm 2-10 keV}$ / $L_{\rm IR}$] ratio is consistent
with those found in PG Quasars. The 0.5-10 keV spectrum of PKS 1345+12 and Arp
220 seem unchanged from previous observations and their hard X-ray emission is
not convincingly detected by the HXD/PIN. The large column density derived from
CO observations and the large equivalent width of an ionized Fe line in Arp 220
can be reconciled by an ionized reflection model. F08572+3915 is undetected in
both the XIS and HXD/PIN, but the analysis of unpublished {\em Chandra} data
provides a new measurement at low energies.


title:
Properties of Galaxies Hosting X-ray Selected Active Galactic Nuclei in
  the Cl1604 Supercluster at z=0.9

abstract:
  To investigate the role of feedback from Active Galactic Nuclei (AGN) in
driving the evolution of their host galaxies, we have carried out a study of
the environments and optical properties of galaxies harboring X-ray luminous
AGN in the Cl1604 supercluster at z~0.9. Making use of Chandra, HST/ACS and
Keck/DEIMOS observations, we examine the integrated colors, morphologies and
spectral properties of nine moderate-luminosity (L_x ~ 10^43 erg s^-1) type 2
Seyferts detected in the Cl1604 complex. We find that the AGN are predominantly
hosted by luminous spheroids and/or bulge dominated galaxies which have colors
that place them in the valley between the blue cloud and red sequence in
color-magnitude space, consistent with predictions that AGN hosts should
constitute a transition population. Half of the hosts have bluer overall colors
as a result of blue resolved cores in otherwise red spheroids and a majority
show signs of recent or pending interactions. We also find a substantial number
exhibit strong Balmer absorption features indicative of post-starburst
galaxies, despite the fact that we detect narrow [OII] emission lines in all of
the host spectra. If the [OII] lines are due in part to AGN emission, as we
suspect, then this result implies that a significant fraction of these galaxies
(44%) have experienced an enhanced level of star formation within the last ~1
Gyr which was rapidly suppressed. Overall we find that the properties of the
nine host galaxies are generally consistent with a scenario in which recent
interactions have triggered both increased levels of nuclear activity and an
enhancement of centrally concentrated star formation, followed by a rapid
truncation of the latter, possibly as a result of feedback from the AGN itself.
[Abridged]


title:
The Observations of Redshift Evolution in Large Scale Environments
  (ORELSE) Survey : I. The Survey Design and First Results on Cl 0023+0423 at z
  = 0.84 and RX J1821.6+6827 at z = 0.82

abstract:
  We present the Observations of Redshift Evolution in Large Scale Environments
(ORELSE) survey, a systematic search for structure on scales greater than 10
Mpc around 20 well-known clusters at 0.6 < z < 1.3. We describe the survey
design, the cluster sample, and our extensive observational data covering at
least 25' around each target cluster. We use adaptively-smoothed red galaxy
density maps from our wide-field optical imaging to identify candidate
groups/clusters and intermediate-density large scale filaments/walls in each
cluster field. Because photometric techniques can be highly uncertain, the
crucial component of this survey is the unprecedented amount of spectroscopic
coverage. We are using the wide-field, multi-object spectroscopic capabilities
of the DEep Multi-Object Imaging Spectrograph to obtain 100-200+ confirmed
cluster members in each field. Our survey has already discovered the Cl 1604
supercluster at z = 0.9. Here, we present the results on two additional
clusters, Cl 0023+0423 at z = 0.84 and RX J1821.6+6827 at z = 0.82. The
optically-selected Cl 0023+0423 is a four-way group-group merger with
constituent groups having velocity dispersions between 206-479 km/s. The galaxy
population is dominated by blue, star-forming galaxies, with a substantial
contribution from recent starbursts. In contrast, the X-ray-selected RX
J1821.6+6827 is a largely-isolated, massive cluster with a measured velocity
dispersion of 926 +/- 77 km/s. The cluster exhibits a well defined red sequence
with a large quiescent galaxy population. The results from these two targets,
along with preliminary findings on other ORELSE clusters, suggest that optical
selection may be more effective than X-ray surveys at detecting less-evolved,
dynamically-active systems at these redshifts. [Abridged]


title: An approximation algorithm for approximation rank

abstract:
  One of the strongest techniques available for showing lower bounds on quantum
communication complexity is the logarithm of the approximation rank of the
communication matrix--the minimum rank of a matrix which is entrywise close to
the communication matrix. This technique has two main drawbacks: it is
difficult to compute, and it is not known to lower bound quantum communication
complexity with entanglement.
  Linial and Shraibman recently introduced a norm, called gamma_2^{alpha}, to
quantum communication complexity, showing that it can be used to lower bound
communication with entanglement. Here the parameter alpha is a measure of
approximation which is related to the allowable error probability of the
protocol. This bound can be written as a semidefinite program and gives bounds
at least as large as many techniques in the literature, although it is smaller
than the corresponding alpha-approximation rank, rk_alpha. We show that in fact
log gamma_2^{alpha}(A)$ and log rk_{alpha}(A)$ agree up to small factors. As
corollaries we obtain a constant factor polynomial time approximation algorithm
to the logarithm of approximate rank, and that the logarithm of approximation
rank is a lower bound for quantum communication complexity with entanglement.


title: Polarized Far-Infrared and Submillimeter Emission from Interstellar Dust

abstract:
  Polarized far-infrared and submillimeter emission is calculated for models of
nonspherical dust grains that are constrained to reproduce the observed
wavelength-dependent extinction and polarization of starlight. For emission
from regions where the magnetic field is perpendicular to the line-of-sight,
the far-infrared emission is expected to have substantial linear polarization
at wavelengths longer than 100 microns, but the degree of linear polarization,
and its variation with wavelength, is model-dependent. Models in which the
starlight polarization is produced by both amorphous silicate and graphite
grains have linear polarizations between 6% and 10% at wavelengths longer than
100 microns, but for some models in which only silicate grains are spheroidal,
the linear polarization increases from about 3% at 100 microns to about 15% at
1 mm. We briefly discuss the implications of these results for removal of the
polarized dust emission from maps of the Cosmic Microwave Background, as well
as the possibility of discriminating among interstellar dust models based on
observations of far-infrared and submillimeter linear polarization.


title:
Kozai cycles, tidal friction and the dynamical evolution of binary minor
  planets

abstract:
  In recent years many binary minor planets (BMPs) have been discovered in the
Solar system. Many models have been suggested for their formation, but these
encounter difficulties explaining their observed characteristics. Here we show
that secular perturbations by the Sun (Kozai mechanism) fundamentally change
the evolution and the initial distribution of BMPs predicted by such models and
lead to unique observational signatures. The Kozai mechanism can lead to a
large periodic oscillations in the eccentricity and inclination of highly
inclined BMP orbits, where we predict such effects to be observable with
current accuracy within a few years (e.g. for the binary asteroid Huenna). In
addition, the combined effects of the Kozai mechanism and tidal friction (KCTF)
drives BMPs into short period circular orbits. We predict a specific
inclination dependent distribution of the separation and eccentricity of BMPs,
due to these effects, including a zone of avoidance at the highest
inclinations. Specifically the Kozai evolution could explain the recently
observed peculiar orbit of the Kuiper belt binary 2001 QW322 . Additionally,
the KCTF process could lead to BMPs coalescence and serve as an important route
for the formation of irregular shaped single minor planets with large axial
tilts.


title: Electroweak scale seesaw and heavy Dirac neutrino signals at LHC

abstract:
  Models of type I seesaw can be implemented at the electroweak scale in a
natural way provided that the heavy neutrino singlets are quasi-Dirac
particles. In such case, their contribution to light neutrino masses has the
suppression of a small lepton number violating parameter, so that light
neutrino masses can arise naturally even if the seesaw scale is low and the
heavy neutrino mixing is large. We implement the same mechanism with fermionic
triplets in type III seesaw, deriving the interactions of the new quasi-Dirac
neutrinos and heavy charged leptons with the SM fermions. We then study the
observability of heavy Dirac neutrino singlets (seesaw I) and triplets (seesaw
III) at LHC. Contrarily to common wisdom, we find that heavy Dirac neutrino
singlets with a mass around 100 GeV are observable at the 5 sigma level with a
luminosity of 13 fb^-1. Indeed, in the final state with three charged leptons
l+- l+- l-+, not previously considered, Dirac neutrino signals can be
relatively large and backgrounds are small. In the triplet case, heavy
neutrinos can be discovered with a luminosity of 1.5 fb^-1 for a mass of 300
GeV in the same channel.


title: Algorithms for Locating Constrained Optimal Intervals

abstract:
  In this work, we obtain the following new results.
  1. Given a sequence $D=((h_1,s_1), (h_2,s_2) ..., (h_n,s_n))$ of number
pairs, where $s_i>0$ for all $i$, and a number $L_h$, we propose an O(n)-time
algorithm for finding an index interval $[i,j]$ that maximizes
$\frac{\sum_{k=i}^{j} h_k}{\sum_{k=i}^{j} s_k}$ subject to $\sum_{k=i}^{j} h_k
\geq L_h$.
  2. Given a sequence $D=((h_1,s_1), (h_2,s_2) ..., (h_n,s_n))$ of number
pairs, where $s_i=1$ for all $i$, and an integer $L_s$ with $1\leq L_s\leq n$,
we propose an $O(n\frac{T(L_s^{1/2})}{L_s^{1/2}})$-time algorithm for finding
an index interval $[i,j]$ that maximizes $\frac{\sum_{k=i}^{j}
h_k}{\sqrt{\sum_{k=i}^{j} s_k}}$ subject to $\sum_{k=i}^{j} s_k \geq L_s$,
where $T(n')$ is the time required to solve the all-pairs shortest paths
problem on a graph of $n'$ nodes. By the latest result of Chan \cite{Chan},
$T(n')=O(n'^3 \frac{(\log\log n')^3}{(\log n')^2})$, so our algorithm runs in
subquadratic time $O(nL_s\frac{(\log\log L_s)^3}{(\log L_s)^2})$.


title: Photometric redshift and classification for the XMM-COSMOS sources

abstract:
  We present photometric redshifts and spectral energy distribution (SED)
classifications for a sample of 1542 optically identified sources detected with
XMM in the COSMOS field. Our template fitting classifies 46 sources as stars
and 464 as non-active galaxies, while the remaining 1032 require templates with
an AGN contribution. High accuracy in the derived photometric redshifts was
accomplished as the result of 1) photometry in up to 30 bands with high
significance detections, 2) a new set of SED templates including 18 hybrids
covering the far-UV to mid-infrared, which have been constructed by the
combination of AGN and non-active galaxies templates, and 3) multi-epoch
observations that have been used to correct for variability (most important for
type 1 AGN). The reliability of the photometric redshifts is evaluated using
the sub-sample of 442 sources with measured spectroscopic redshifts. We
achieved an accuracy of $\sigma_{\Delta z/(1+z_{spec})} = 0.014$ for
i$_{AB}^*<$22.5 ($\sigma_{\Delta z/(1+z_{spec})} \sim0.015$ for
i$_{AB}^*<$24.5). The high accuracies were accomplished for both type 2 (where
the SED is often dominated by the host galaxy) and type 1 AGN and QSOs out to
$z=4.5$. The number of outliers is a large improvement over previous
photometric redshift estimates for X-ray selected sources (4.0% and 4.8%
outliers for i$_{AB}^*<$22.5 and i$_{AB}^*<$24.5, respectively). We show that
the intermediate band photometry is vital to achieving accurate photometric
redshifts for AGN, whereas the broad SED coverage provided by mid infrared
(Spitzer/IRAC) bands is important to reduce the number of outliers for normal
galaxies.


title: Acceleration of Galactic Supershells by Lyman Alpha Radiation

abstract:
  Scattering of Lyman Alpha (hereafter Lya) photons by neutral hydrogen gas in
a single outflowing 'supershell' around star forming regions often explains the
shape and offset of the observed Lya emission line from galaxies. We compute
the radiation pressure that is exerted by this scattered Lya radiation on the
outflowing material. We show that for reasonable physical parameters, Lya
radiation pressure alone can accelerate supershells to velocities in the range
v_sh=200-400 km/s. These supershells possibly escape from the gravitational
potential well of their host galaxies and contribute to the enrichment of the
intergalactic medium. We compute the physical properties of expanding
supershells that are likely to be present in a sample of known high-redshift
(z=2.7-5.0) galaxies, under the assumption that they are driven predominantly
by Lya radiation pressure. We predict ranges of radii r_sh=0.1-10 kpc, ages
t_sh=1-100 Myr, and energies E_sh=1e53-1e55 ergs, which are in reasonable
agreement with the properties of local galactic supershells. Furthermore, we
find that the radius, r_sh, of a Lya-driven supershell of constant mass depends
uniquely on the intrinsic Lya luminosity of the galaxy, L_alpha, the HI column
density of the supershell, N_HI, and the shell speed, v_sh, through the scaling
relation r_sh ~ L_alpha/(N_HI v_sh^2). We derive mass outflow rates in
supershells that reach ~10-100% of the star formation rates of their host
galaxies.


title: On topological spin excitations on a rigid torus

abstract:
  We study Heisenberg model of classical spins lying on the toroidal support,
whose internal and external radii are $r$ and $R$, respectively. The isotropic
regime is characterized by a fractional soliton solution. Whenever the torus
size is very large, $R\to\infty$, its charge equals unity and the soliton
effectively lies on an infinite cylinder. However, for R=0 the spherical
geometry is recovered and we obtain that configuration and energy of a soliton
lying on a sphere. Vortex-like configurations are also supported: in a ring
torus ($R>r$) such excitations present no core where energy could blow up. At
the limit $R\to\infty$ we are effectively describing it on an infinite
cylinder, where the spins appear to be practically parallel to each other,
yielding no net energy. On the other hand, in a horn torus ($R=r$) a singular
core takes place, while for $R<r$ (spindle torus) two such singularities
appear. If $R$ is further diminished until vanish we recover vortex
configuration on a sphere.


title: COSMOS Photometric Redshifts with 30-bands for 2-deg2

abstract:
  We present accurate photometric redshifts in the 2-deg2 COSMOS field. The
redshifts are computed with 30 broad, intermediate, and narrow bands covering
the UV (GALEX), Visible-NIR (Subaru, CFHT, UKIRT and NOAO) and mid-IR
(Spitzer/IRAC). A chi2 template-fitting method (Le Phare) was used and
calibrated with large spectroscopic samples from VLT-VIMOS and Keck-DEIMOS. We
develop and implement a new method which accounts for the contributions from
emission lines (OII, Hbeta, Halpha and Ly) to the spectral energy distributions
(SEDs). The treatment of emission lines improves the photo-z accuracy by a
factor of 2.5. Comparison of the derived photo-z with 4148 spectroscopic
redshifts (i.e. Delta z = zs - zp) indicates a dispersion of sigma_{Delta
z/(1+zs)}=0.007 at i<22.5, a factor of 2-6 times more accurate than earlier
photo-z in the COSMOS, CFHTLS and COMBO-17 survey fields. At fainter magnitudes
i<24 and z<1.25, the accuracy is sigma_{Delta z/(1+zs)}=0.012. The deep NIR and
IRAC coverage enables the photo-z to be extended to z~2 albeit with a lower
accuracy (sigma_{Delta z/(1+zs)}=0.06 at i~24). The redshift distribution of
large magnitude-selected samples is derived and the median redshift is found to
range from z=0.66 at 22<i<22.5 to z=1.06 at 24.5<i<25. At i<26.0, the
multi-wavelength COSMOS catalog includes approximately 607,617 objects. The
COSMOS-30 photo-z enable the full exploitation of this survey for studies of
galaxy and large scale structure evolution at high redshift.


title: Gregor Wentzel

abstract: We review the life and remarkable contributions to Physics of Gregor Wentzel.


title: How hole defects modify vortex dynamics in ferromagnetic nanodisks

abstract:
  Defects introduced in ferromagnetic nanodisks may deeply affect the structure
and dynamics of stable vortex-like magnetization. Here, analytical techniques
are used for studying, among other dynamical aspects, how a small cylindrical
cavity modify the oscillatory modes of the vortex. For instance, we have
realized that if the vortex is nucleated out from the hole its gyrotropic
frequencies are shifted below. Modifications become even more pronounced when
the vortex core is partially or completely captured by the hole. In these
cases, the gyrovector can be partially or completely suppressed, so that the
associated frequencies increase considerably, say, from some times to several
powers. Possible relevance of our results for understanding other aspects of
vortex dynamics in the presence of cavities and/or structural defects are also
discussed.


title: Inflation scenario via the Standard Model Higgs boson and LHC

abstract:
  We consider a quantum corrected inflation scenario driven by a generic GUT or
Standard Model type particle model whose scalar field playing the role of an
inflaton has a strong non-minimal coupling to gravity. We show that currently
widely accepted bounds on the Higgs mass falsify the suggestion of the paper
arXiv:0710.3755 (where the role of radiative corrections was underestimated)
that the Standard Model Higgs boson can serve as the inflaton. However, if the
Higgs mass could be raised to $\sim 230$ GeV, then the Standard Model could
generate an inflationary scenario with the spectral index of the primordial
perturbation spectrum $n_s\simeq 0.935$ (barely matching present observational
data) and the very low tensor-to-scalar perturbation ratio $r\simeq 0.0006$.


title: Magnetic monopole and string excitations in a two-dimensional spin ice

abstract:
  We study the magnetic excitations of a square lattice spin-ice recently
produced in an artificial form, as an array of nanoscale magnets. Our analysis,
based upon the dipolar interaction between the nanomagnetic islands, correctly
reproduces the ground-state observed experimentally. In addition, we find
magnetic monopole-like excitations effectively interacting by means of the
usual Coulombic plus a linear confining potential, the latter being related to
a string-like excitation binding the monopoles pairs, what indicates that the
fractionalization of magnetic dipoles may not be so easy in two dimensions.
These findings contrast this material with the three-dimensional analogue,
where such monopoles experience only the Coulombic interaction. We discuss,
however, two entropic effects that affect the monopole interactions: firstly,
the string configurational entropy may loose the string tension and then, free
magnetic monopoles should also be found in lower dimensional spin ices;
secondly, in contrast to the string configurational entropy, an entropically
driven Coulomb force, which increases with temperature, has the opposite effect
of confining the magnetic defects.


title: Grand Unification and Light Color-Octet Scalars at the LHC

abstract:
  We study the properties and production mechanisms of color-octet scalars at
the LHC. We focus on the single production of both charged and neutral members
of an (8,2)_1/2 doublet through bottom quark initial states. These channels
provide a window to the underlying Yukawa structure of the scalar sector.
Color-octet scalars naturally appear in grand unified theories based on the
SU(5) gauge symmetry. In the context of adjoint SU(5) these fields are expected
to be light to satisfy constraints coming from unification and proton decay,
and may have TeV-scale masses. One combination of their couplings is defined by
the relation between the down-quark and charged-lepton Yukawa couplings.
Observation of these states at the LHC gives an upper bound on the proton
lifetime if they truly arise from this grand unified theory. We demonstrate
that TeV-mass scalars can be observed over background at the LHC using boosted
top quark final states, and study how well the scalar Yukawa parameters can be
measured.


title: Cosmological backreaction and spatially averaged spatial curvature

abstract:
  It has been suggested that the accelerated expansion of the Universe is due
to backreaction of small scale density perturbations on the large scale
spacetime geometry. While evidence against this suggestion has accumulated, it
has not yet been definitively ruled out. Many investigations of this issue have
focused on the Buchert formalism, which computes spatial averages of quantities
in synchronous comoving gauge. We argue that, for the deceleration parameter of
this formalism to agree with observations, the spatial average of the three
dimensional Ricci scalar (spatial curvature) must be large today, with an
$\Omega_k$ in the range of $1 \le \Omega_k \le 1.3$. We argue that this
constraint is difficult to reconcile with observations of the location of the
first Doppler peak of the CMBR. We illustrate the argument with a simple toy
model for the effect of backreaction, which we show is generically incompatible
with observations.


title:
Singe ferroelectric and chiral magnetic domain of single-crystalline
  BiFeO$_3$ in an electric field

abstract:
  We report polarized neutron scattering and piezoresponse force microscopy
studies of millimeter-sized single crystals of multiferroic BiFeO$_3$. The
crystals, grown below the Curie temperature, consist of a single ferroelectric
domain. Two unique electric polarization directions, as well as the populations
of equivalent spiral magnetic domains, can be switched reversibly by an
electric field. A ferroelectric monodomain with a single-$q$ single-helicity
spin spiral can be obtained. This level of control, so far unachievable in thin
films, makes single-crystal BiFeO$_3$ a promising object for multiferroics
research.


title: Josephson current noise above Tc in superconducting tunnel junctions

abstract:
  Tunnel junction between two superconductors is considered in the vicinity of
the critical temperature. Superconductive fluctuations above Tc give rise to
the noise of the ac Josephson current although the current itself is zero in
average. As a result of fluctuations, current noise spectrum is peaked at the
Josephson frequency, which may be considered as precursor of superconductivity
in the normal state. Temperature dependence and shape of the Josephson current
noise resonance line is calculated for various junction configurations.


title:
Optically induced spin gates in coupled quantum dots using the
  electron-hole exchange interaction

abstract:
  We propose a fast optically induced two-qubit \textsc{c-phase} gate between
two resident spins in a pair of coupled quantum dots. An excited bound state
which extends over the two dots provides an effective electron-electron
exchange interaction. The gate is made possible by the electron-hole exchange
interaction, which isolates a single transition in the system. When combined
with appropriate single qubit rotations, this gate generates an entangled state
of the two spins.


title: Organizing Volumes of Right-Angled Hyperbolic Polyhedra

abstract:
  This article defines a pair of combinatorial operations on the combinatorial
structure of compact right-angled hyperbolic polyhedra in dimension three
called decomposition and edge surgery. It is shown that these operations
simplify the combinatorics of such a polyhedron, while keeping it within the
class of right-angled objects, until it is a disjoint union of L\"obell
polyhedra, a class of polyhedra which generalizes the dodecahedron.
Furthermore, these combinatorial operations are shown to have geometric
realizations which are volume decreasing. This allows for an organization of
the volumes of right-angled hyperbolic polyhedra and allows, in particular, the
determination of the polyhedra with smallest and second-smallest volumes.


title:
Near-Infrared spectral diagnostics for unresolved stellar population
  galaxies

abstract:
  We want to develop spectral diagnostics of stellar populations in the
near-infrared (NIR), for unresolved stellar populations. We created a
semi-empirical population model and we compare the model output with the
observed spectra of a sample of elliptical and bulge-dominated galaxies that
have reliable Lick-indices from literature to test if the correlation between
Mg2 and CO 1.62 micron remains valid in galaxies and to calibrate it as an
abundance indicator. We find that (i) there are no significant correlations
between any NIR feature and the optical Mg2; (ii) the CaI, NaI and CO trace the
alpha-enhancement; and (iii) the NIR absorption features are not influenced by
the galaxy's age.


title: Mapping of ion beam induced current changes in FinFETs

abstract:
  We report on progress in ion placement into silicon devices with scanning
probe alignment. The device is imaged with a scanning force microscope (SFM)
and an aligned argon beam (20 keV, 36 keV) is scanned over the transistor
surface. Holes in the lever of the SFM tip collimate the argon beam to sizes of
1.6 um and 100 nm in diameter. Ion impacts upset the channel current due to
formation of positive charges in the oxide areas. The induced changes in the
source-drain current are recorded in dependence of the ion beam position in
respect to the FinFET. Maps of local areas responding to the ion beam are
obtained.


title: Renormalization and blow up for the critical Yang-Mills problem

abstract:
  We consider the Yangs-Mills equations in 4+1 dimensions. This is the energy
critical case and we show that it admits a family of solutions which blow up in
finite time. They are obtained by the spherically symmetric ansatz in the SO(4)
gauge group and result by rescaling of the instanton solution. The rescaling is
done via a prescribed rate which in this case is a modification of the
self-similar rate by a power of |log t|. The powers themselves take any value
exceeding 3/2 and thus form a continuum of distinct rates leading to blow-up.
The methods are related to the authors' previous work on wave maps and the
energy critical semi-linear equation. However, in contrast to these equations,
the linearized Yang-Mills operator (around an instanton) exhibits a zero energy
eigenvalue rather than a resonance. This turns out to have far-reaching
consequences, amongst which are a completely different family of rates leading
to blow-up (logarithmic rather than polynomial corrections to the self-similar
rate).


title: Control of wavepacket spreading in nonlinear finite disordered lattices

abstract:
  In the absence of nonlinearity all normal modes (NMs) of a chain with
disorder are spatially localized (Anderson localization). We study the action
of nonlinearity, whose strength is ramped linearly in time. It leads to a
spreading of a wavepacket due to interaction with and population of distant
NMs. Eventually the nonlinearity induced frequency shifts take over, and the
wavepacket becomes selftrapped. On finite chains a critical ramping speed is
obtained, which separates delocalized final states from localized ones. The
critical value depends on the strength of disorder and is largest when the
localization length matches the system size.


title:
Remarks on Automorphisms of $\mathbb{C}^* \times \mathbb{C}^*$ and their
  basins

abstract:
  We study basins of attraction of automorphisms of $\CC^2$ tangent to the
identity that fix both axes. Our main result is that, if a well known
conjecture about automorphisms of $\CC^*\times\CC^*$ holds, then there are no
basins of attraction associated to the non-degenerate characteristic directions
(in the sense of Hakim), and therefore we cannot find a Fatou-Bieberbach domain
that does not intersect both axis with this method.


title: Synchronization on directed small worlds: feed forward loops and cycles

abstract:
  In this paper we investigate the influence of directed motifs on the
synchronization properties of Kuramoto oscillators on directed networks.
Building different types of sparse directed small world networks similar to the
Watts and Strogatz procedure we establish that feed forward loops favour
synchronization on directed networks. The paper highlights the importance of
local network characteristics for synchronization.


title:
Bosonization of Matter $\beta\gamma$ CFT, Non-compact Coordinate and
  Noncritical String Theory

abstract:
  We consider a (supersymmetric) bosonization of general commuting matter
$\beta\gamma$ CFT. Unlike the conventional ghost $\beta\gamma$ CFT
bosonization, which is typically described in terms of one scalar and one set
of $\xi\eta$ CFT, the matter $\beta\gamma$ CFT is naturally bosonized to two
scalar CFTs. Surprisingly, there exists an independent subsector, which
satisfies a constraint necessary for consistent bosonization, while the usual
sector has a description in terms of two compact coordinates. The subsector
itself is a complete system which is equivalent to the original $\beta\gamma$
CFT. Furthermore, a non-compact coordinate naturally emerges in this
"non-compact subsector". As an immediate application, we consider the
bosonization of matter $\beta\gamma$ CFT in the context of full string theory
and find the connection to noncritical string theories in the light-cone gauge.


title:
Universality in the Photophysics of pi-Conjugated Polymers and
  Single-Walled Carbon Nanotubes

abstract:
  We describe both pi-conjugated polymers and semiconducting single-walled
carbon nanotubes because of the remarkable similarities in their behavior under
photoexcitation. The common themes between these two seemingly different
classes of materials are pi-conjugation, quasi one-dimensionality, and strong
Coulomb interactions. Theoretical understanding of both systems requires going
beyond traditional band theory. We present our current understanding of the
electronic structures and excited state absorptions in both systems within a
common theoretical model. Our aim is to give physical interpretations of
experiments that have been performed and to give guidance to future
experimental work.


title:
Frequency Variation of the Kilohertz Quasi-periodic Oscillations and the
  Flux of the Band-limited Noise in Scorpius X-1

abstract:
  We study the kilohertz quasi-periodic oscillations (kHz QPOs) and the
band-limited noise (BLN) in the 0.5--16 Hz range observed simultaneously on the
horizontal branch (HB) and on the upper normal branch (NB) of the brightest
neutron star Low-mass X-ray Binary (LMXB) Scorpius X--1 with the observations
performed with the {\it Rossi X-Ray Timing Explorer (RXTE)}. We find that the
twin kHz QPO frequencies are positively correlated with the flux variations
taking place on the BLN time scales on the HB, in contrast to the
anti-correlation held on the time scale of the normal branch oscillation (NBO)
on the NB reported previously, suggesting that although they occur in sequence
along the color-color tracks, the BLN and the NBO are of different origins. We
also show the evidence that the frequency separation between the twin kHz QPOs
decreases with the flux by $2\sim~3$ Hz on the BLN time scales, which is
consistent with the trend on the longer time scale that the Z source traces the
HB. This further suggests that the flux variation associated with the BLN
originates from the mass accretion rate variation in the disk accretion flow.
We discuss the implications of these results for our understanding of the BLN.


title:
Morphisms from Azumaya prestable curves with a fundamental module to a
  projective variety: Topological D-strings as a master object for curves

abstract:
  This is a continuation of our study of the foundations of D-branes from the
viewpoint of Grothendieck in the region of the related Wilson's theory-space
where "branes" are still branes. In this work, we focus on D-strings and
construct the moduli stack of morphisms from Azumaya prestable curves $C^{Az}$
with a fundamental module ${\cal E}$ to a fixed target $Y$ of a given
combinatorial type. Such a morphism gives a prototype for a Wick-rotated
D-string of B-type on $Y$, following the Polchinski-Grothendieck Ansatz, and
this stack serves as a ground toward a mathematical theory of topological
D-string world-sheet instantons.


title: Dimensionality reduction in translational noninvariant wave guides

abstract:
  A scheme to reduce translational noninvariant quasi-one-dimensional wave
guides into singly or multiply connected one-dimensional (1D) lines is
proposed. It is meant to simplify the analysis of wave guides, with the
low-energy properties of the guides preserved. Guides comprising
uniform-cross-sectional sections and discontinuities such as bends and
branching junctions are considered. The uniform sections are treated as 1D
lines, and the discontinuities are described by equations sets connecting the
wave functions on the lines. The procedures to derive the equations and to
solve reduced systems are illustrated by examples, and the scheme is found to
apply when the discontinuities are distant and the energy is low. When the
scheme applies, it may substantially simplify the analysis of a wave guide, and
hence the scheme may find uses in the study of related problems, such as
quantum wire networks.


title:
Statefinder parameters for quantum effective Yang-Mills condensate dark
  energy model

abstract:
  The quantum effective Yang-Mills condensate (YMC) dark energy model has some
distinguished features that it naturally solves the coincidence problem and, at
the same time, is able to give an equation of state $w$ crossing -1. In this
work we further employ the Statefinder pair $(r,s)$ introduced by Sahni et al
to diagnose the YMC model for three cases: the non-coupling, the YMC decaying
into matter only, and the YMC decaying into both matter and radiation. The
trajectories $(r,s)$ and $(r,q)$, and the evolutions $r(z)$, $s(z)$ are
explicitly presented. It is found that, the YMC model in all three cases has
$r\simeq 1$ for $ z < 10$ and $s\simeq 0$ for $z<5$ with only small deviations
$\simeq 0.02$, quite close to the cosmological constant model (LCDM), but is
obviously differentiated from other dark energy models, such as quiesence,
kinessence etc.


title:
Iterated function systems, moments, and transformations of infinite
  matrices

abstract:
  We study the moments of equilibrium measures for iterated function systems
(IFSs) and draw connections to operator theory. Our main object of study is the
infinite matrix which encodes all the moment data of a Borel measure on R^d or
C. To encode the salient features of a given IFS into precise moment data, we
establish an interdependence between IFS equilibrium measures, the encoding of
the sequence of moments of these measures into operators, and a new
correspondence between the IFS moments and this family of operators in Hilbert
space. For a given IFS, our aim is to establish a functorial correspondence in
such a way that the geometric transformations of the IFS turn into
transformations of moment matrices, or rather transformations of the operators
that are associated with them.
  We first examine the classical existence problem for moments, culminating in
a new proof of the existence of a Borel measure on R or C with a specified list
of moments. Next, we consider moment problems associated with affine and
non-affine IFSs. Our main goal is to determine conditions under which an
intertwining relation is satisfied by the moment matrix of an equilibrium
measure of an IFS. Finally, using the famous Hilbert matrix as our prototypical
example, we study boundedness and spectral properties of moment matrices viewed
as Kato-Friedrichs operators on weighted l^2 spaces.


title:
Numerical solution of a certain type of integral equations on the real
  half-line

abstract:
  We develop a numerical method for solving a system of nonlinear integral
equations involving two integral terms: at the current time t, one integral is
taken from 0 to t, and a different integral is taken from t to infinity. We
prove the convergence and the rate of convergence of our method. The
discretization results in an infinite-dimensional nonlinear system, and we also
prove results on the approximation of the solution of the infinite-dimensional
system by solution of finite truncations.


title: An Atomic-resolution nanomechanical mass sensor

abstract:
  Mechanical resonators are widely used as inertial balances to detect small
quantities of adsorbed mass through shifts in oscillation frequency[1].
Advances in lithography and materials synthesis have enabled the fabrication of
nanoscale mechanical resonators[2, 3, 4, 5, 6], which have been operated as
precision force[7], position[8, 9] and mass sensors[10, 11, 12, 13, 14, 15].
Here we demonstrate a room-temperature, carbon-nanotube-based nanomechanical
resonator with atomic mass resolution. This device is essentially a mass
spectrometer with a mass sensitivity of 1.3 times 10^-25 kg Hz^-1/2 or,
equivalently, 0.40 gold atoms Hz^-1/2. Using this extreme mass sensitivity, we
observe atomic mass shot noise, which is analogous to the electronic shot
noise[16, 17] measured in many semiconductor experiments. Unlike traditional
mass spectrometers, nanomechanical mass spectrometers do not require the
potentially destructive ionization of the test sample, are more sensitive to
large molecules, and could eventually be incorporated on a chip.


title:
Generalized Whittaker functions for degenerate principal series of
  $GL(4,\R)$

abstract:
  We give a characterization of a generalized Whittaker model of a degenerate
principal series representation of $GL(n,\R)$ as the kernel of some
differential operators. By this characterization, we investigate some examples
on $GL(4,\R)$. We obtain the dimensions of the generalized Whittaker models and
give their basis in terms of hypergeometric functions of one and two variables.
We show the multiplicity one of the generalized Whittaker models by using the
theory of hypergeometric functions.


title: Reactor monitoring and safeguards using antineutrino detectors

abstract:
  Nuclear reactors have served as the antineutrino source for many fundamental
physics experiments. The techniques developed by these experiments make it
possible to use these very weakly interacting particles for a practical
purpose. The large flux of antineutrinos that leaves a reactor carries
information about two quantities of interest for safeguards: the reactor power
and fissile inventory. Measurements made with antineutrino detectors could
therefore offer an alternative means for verifying the power history and
fissile inventory of a reactors, as part of International Atomic Energy Agency
(IAEA) and other reactor safeguards regimes. Several efforts to develop this
monitoring technique are underway across the globe.


title:
Exact Results for the Kuramoto Model with a Bimodal Frequency
  Distribution

abstract:
  We analyze a large system of globally coupled phase oscillators whose natural
frequencies are bimodally distributed. The dynamics of this system has been the
subject of long-standing interest. In 1984 Kuramoto proposed several
conjectures about its behavior; ten years later, Crawford obtained the first
analytical results by means of a local center manifold calculation.
Nevertheless, many questions have remained open, especially about the
possibility of global bifurcations. Here we derive the system's complete
stability diagram for the special case where the bimodal distribution consists
of two equally weighted Lorentzians. Using an ansatz recently discovered by Ott
and Antonsen, we show that in this case the infinite-dimensional problem
reduces exactly to a flow in four dimensions. Depending on the parameters and
initial conditions, the long-term dynamics evolves to one of three states:
incoherence, where all the oscillators are desynchronized; partial synchrony,
where a macroscopic group of phase-locked oscillators coexists with a sea of
desynchronized ones; and a standing wave state, where two counter-rotating
groups of phase-locked oscillators emerge. Analytical results are presented for
the bifurcation boundaries between these states. Similar results are also
obtained for the case in which the bimodal distribution is given by the sum of
two Gaussians.


title: The volume of a differentiable stack

abstract:
  We extend the notion of the cardinality of a discrete groupoid (equal to the
Euler characteristic of the corresponding discrete orbifold) to the setting of
Lie groupoids. Since this quantity is an invariant under equivalence of
groupoids, we call it the volume of the associated stack rather than of the
groupoid itself. Since there is no natural measure in the smooth case like the
counting measure in the discrete case, we need extra data to define the volume.
This data has the form of an invariant section of a natural line bundle over
the groupoid. Sections of a square root of this line bundle constitute an
"intrinsic Hilbert space" of the stack.


title: Accurate statistics of a flexible polymer chain in shear flow

abstract:
  We present exact and analytically accurate results for the problem of a
flexible polymer chain in shear flow. Under such a flow the polymer tumbles,
and the probability distribution of the tumbling times $\tau$ of the polymer
decays exponentially as $\sim \exp(-\alpha \tau/\tau_0)$ (where $\tau_0$ is the
longest relaxation time). We show that for a Rouse chain, this nontrivial
constant $\alpha$ can be calculated in the limit of large Weissenberg number
(high shear rate) and is in excellent agreement with our simulation result of
$\alpha \simeq 0.324$. We also derive exactly the distribution functions for
the length and the orientational angles of the end-to-end vector of the
polymer.


title:
A Correlation of Spectral Lag Evolution with Prompt Optical Emission in
  GRBs?

abstract:
  We report on observations of correlated behavior between the prompt gamma-ray
and optical emission from GRB 080319B, which (i) strongly suggest that they
occurred within the same astrophysical source region and (ii) indicate that
their respective radiation mechanisms were most likely dynamically coupled. Our
preliminary results, based upon a new cross-correlation function (CCF)
methodology for determining the time-resolved spectral lag, are summarized as
follows. First, the evolution in the arrival offset of prompt gamma-ray photon
counts between Swift-BAT 15-25 keV and 50-100 keV energy bands (intrinsic
gamma-ray spectral lag) appears to be anti-correlated with the arrival offset
between prompt 15-350 keV gamma-rays and the optical emission observed by
TORTORA (extrinsic optical/gamma-ray spectral lag), thus effectively
partitioning the burst into two main episodes at ~T+28+/-2 sec. Second, prompt
optical emission is nested within intervals of (a) trivial intrinsic gamma-ray
spectral lag (~T+12+-2 and ~T+50+/-2 sec) with (b) discontinuities in the hard
to soft evolution of the photon index for a power law fit to 15-150 keV
Swift-BAT data (~T+8+/-2 and ~T+48+/-1 sec), both of which coincide with the
rise (~T+10+/-1 sec) and decline (~T+50+/-1 sec) of prompt optical emission.
This potential discovery, robust across heuristic permutations of BAT energy
channels and varying temporal bin resolution, provides the first observational
evidence for an implicit connection between spectral lag and the dynamics of
shocks in the context of canonical fireball phenomenology.


title: High speed quantum gates with cavity quantum electrodynamics

abstract:
  Cavity quantum electrodynamic schemes for quantum gates are amongst the
earliest quantum computing proposals. Despite continued progress, and the
dramatic recent demonstration of photon blockade, there are still issues with
optimal coupling and gate operation involving high-quality cavities. Here we
show dynamic control techniques that allow scalable cavity-QED based quantum
gates, that use the full bandwidth of the cavities. When applied to quantum
gates, these techniques allow an order of magnitude increase in operating
speed, and two orders of magnitude reduction in cavity Q, over passive
cavity-QED architectures. Our methods exploit Stark shift based Q-switching,
and are ideally suited to solid-state integrated optical approaches to quantum
computing.


title: Containment in (s,t)-core Partitions

abstract:
  We introduce the idea of (s,t)-closure and delta-sets and show that
(s,t)-closed beta-sets which are contained set-wise in (s,t)-closed delta-sets
are also contained partition-wise. This implies the maximal (s,t)-core
partition theorem of Olsson and Stanton. Along the way, we reprove the
(s,s+1)-core case, originally proved by Olsson and Stanton, using new
techniques, and several lemmas and propositions regarding the containment of
partitions are presented as well. Finally, we study how these apply to
partitions which are T-core.


title: Extending Cantor Paradox

abstract:
  The inconsistencies involved in the foundation of set theory were invariably
caused by infinity and self-reference; and only with the opportune axiomatic
restrictions could them be obviated. Throughout history, both concepts have
proved to be an exhaustible source of paradoxes and contradictions. It seems
therefore legitimate to pose some questions concerning their formal
consistency. This is just the objective of this paper. Starting from an
extension of Cantor's paradox that suggests the inconsistency of the actual
infinity, the paper makes a short review of its controversial history and
proposes a new way of criticism based on w-order. Self-reference is also
examined from a critique perspective which includes syntactic and semantic
considerations. The critique affects the formal sentence involved in Godel's
first incompleteness theorem and its ordinary language interpretation.


title: The Potluck Problem

abstract:
  This paper proposes the Potluck Problem as a model for the behavior of
independent producers and consumers under standard economic assumptions, as a
problem of resource allocation in a multi-agent system in which there is no
explicit communication among the agents.