title: USLV: Unspanned Stochastic Local Volatility Model

abstract:
  We propose a new framework for modeling stochastic local volatility, with
potential applications to modeling derivatives on interest rates, commodities,
credit, equity, FX etc., as well as hybrid derivatives. Our model extends the
linearity-generating unspanned volatility term structure model by Carr et al.
(2011) by adding a local volatility layer to it. We outline efficient numerical
schemes for pricing derivatives in this framework for a particular four-factor
specification (two "curve" factors plus two "volatility" factors). We show that
the dynamics of such a system can be approximated by a Markov chain on a
two-dimensional space (Z_t,Y_t), where coordinates Z_t and Y_t are given by
direct (Kroneker) products of values of pairs of curve and volatility factors,
respectively. The resulting Markov chain dynamics on such partly "folded" state
space enables fast pricing by the standard backward induction. Using a
nonparametric specification of the Markov chain generator, one can accurately
match arbitrary sets of vanilla option quotes with different strikes and
maturities. Furthermore, we consider an alternative formulation of the model in
terms of an implied time change process. The latter is specified
nonparametrically, again enabling accurate calibration to arbitrary sets of
vanilla option quotes.


title:
The Bivariate Size-luminosity Relations for Lyman Break Galaxies at z ~
  4 - 5

abstract:
  We study the bivariate size-luminosity distribution of Lyman Break Galaxies
(LBGs) selected at redshifts around 4 and 5 in GOODS and the HUDF fields. We
model the size-luminosity distribution as a combination of log-normal
distribution (in size) and Schechter function (in luminosity), therefore it
enables a more detailed study of the selection effects. We perform extensive
simulations to quantify the dropout-selection completenesses and measurement
biases and uncertainties in two-dimensional size and magnitude bins, and
transform the theoretical size-luminosity distribution to the expected
distribution for the observed data. Using maximum-likelihood estimator (MLE),
we find that the Schechter function parameters for B-dropouts are
\alpha=-1.68^{+0.068}_{-0.095}, M*=-20.60^{+0.13}_{-0.17}, and
\phi*=1.79^{+0.32}_{-0.52} x 10^{-3} Mpc^{-3}. The log-normal size distribution
is characterized by the peak R_0=1.34^{+0.099}_{-0.108} kpc at M_{1500}=-21
mag, width \sigma_{\lnR}=0.83^{+0.046}_{-0.044}, and the slope of the
size-luminosity (RL) relation \beta=0.22^{+0.058}_{-0.056}. Similarly, for
V-dropouts we find \alpha=-1.74^{+0.15}_{-0.20}, M*=-20.53^{+0.24}_{-0.27},
\phi*=1.55^{+0.62}_{-0.77} x 10^{-3} Mpc}^{-3}, R_0=1.19^{+0.21}_{-0.16} kpc,
\sigma_{\lnR}=0.90^{+0.15}_{-0.065}, and \beta=0.25^{+0.15}_{-0.14}. The
Schechter function parameters are consistent with the values in the literature,
while the size distributions are wider than expected from the angular momentum
distribution of the underlying dark matter halos. The slope of the
size-luminosity (RL) relation is similar to those found for local disk
galaxies, but considerably shallower than local early-type galaxies.


title: Binary Diversity for Non-Binary LDPC Codes over the Rayleigh Channel

abstract:
  In this paper we analyze the performance of several bit-interleaving
strategies applied to Non-Binary Low-Density Parity-Check (LDPC) codes over the
Rayleigh fading channel. The technique of bit-interleaving used over fading
channel introduces diversity which could provide important gains in terms of
frame error probability and detection.
  This paper demonstrates the importance of the way of implementing the
bit-interleaving, and proposes a design of an optimized bit-interleaver
inspired from the Progressive Edge Growth algorithm. This optimization
algorithm depends on the topological structure of a given LDPC code and can
also be applied to any degree distribution and code realization.
  In particular, we focus on non-binary LDPC codes based on graph with constant
symbol-node connection $d_v = 2$. These regular $(2,dc)$-NB-LDPC codes
demonstrate best performance, thanks to their large girths and improved
decoding thresholds growing with the order of Finite Field. Simulations show
excellent results of the proposed interleaving technique compared to the random
interleaver as well as to the system without interleaver.


title: Cosmic Ray Heating of the Warm Ionized Medium

abstract:
  Observations of line ratios in the Milky Way's warm ionized medium (WIM)
suggest that photoionization is not the only heating mechanism present. For the
additional heating to explain the discrepancy it would have to have a weaker
dependence on the gas density than the cooling rate, $\Lambda n_e^2$.
\cite{reynolds99} suggested turbulent dissipation or magnetic field
reconnection as possible heating sources. We investigate here the viability of
MHD-wave mediated cosmic ray heating as a supplemental heating source. This
heating rate depends on the gas density only through its linear dependence on
the Alfv\'en speed, which goes as $n_e^{-1/2}$. We show that, scaled to
appropriate values of cosmic ray energy density, cosmic ray heating can be
significant. Furthermore, this heating is stable to perturbations. These
results should also apply to warm ionized gas in other galaxies.


title: Virtually splitting the map from Aut(G) to Out(G)

abstract:
  We give an elementary criterion on a group G for the map from Aut(G) to
Out(G) to split virtually. This criterion applies to many residually finite
CAT(0) groups and hyperbolic groups, and in particular to all finitely
generated Coxeter groups. As a consequence the outer automorphism group of any
finitely generated Coxeter group is residually finite and virtually
torsion-free.


title: Extending the Hyades

abstract:
  We explore the implications of models of the Hyades moving group in which it
has a resonant origin, for regions of the Galaxy beyond the Solar
neighbourhood. We show that while models associated with different resonances
can produce nearly identical substructure in the local velocity distribution,
the velocity distribution away from the Solar neighbourhood has different
properties for different models. In particular there is a variation between
different models of where in Galactocentric radius the observed Hyades signal
in velocity space is strongest, at a given Galactic azimuth. We note, however,
that the uncertainties in currently available data, primarily due to uncertain
distances to stars, hide these signatures rather effectively, meaning we are
not yet able to determine which resonance is the cause of the Hyades.


title: Proposal to solve a few puzzles in semileptonic B decays

abstract:
  We discussed the impact of the existence of B -> D' l nu decays to radially
excited D' mesons on various long-standing puzzles in the experimental data of
semileptonic b -> c ell nu decays, as summarized in our recent article
arXiv:1202.1834, and updated some numbers.


title:
Influence of Chain Structure and Swelling on the Elasticity of Rubbery
  Materials: Localization Model Description

abstract:
  Classical network elasticity theories are based on the concept of flexible
volumeless polymers fixed into a network in which there are no excluded volume,
or even topological interactions, and where the chains explore accessible
configurations by Brownian motion. In this type of model, the elasticity of the
network derives from the entropic changes arising from a displacement of the
network junction positions. The shortcoming of this approach is clear from the
observation that unswollen rubbery materials are nearly incompressible,
reflecting the existence of strong intermolecular interactions that restrict
the polymer chains to an exploration of their local tube-like molecular
environments. The imposition of a deformation of these solid rubbery materials
then necessitates a consideration of how the local molecular packing
constraints become modified under deformation and the impact of these changes
on the macroscopic elasticity of the material as a whole. Many researchers have
struggled with this difficult problem, in the present paper we focus on the
simple localization model of rubber elasticity of Gaylord and Douglas, which
provides a simple minimal model for the network elasticity of rubbers having
strong intermolecular interactions in the dense polymer state. Particular
emphasis is given in the implications of this model in describing how network
elasticity changes with swelling by a solvent, a phenomenon where large
deviations from classical elasticity have been observed and a situation
relevant to numerous applications involving rubbery materials. We also discuss
the nature of entanglement based on the same packing picture and deduce general
relationships for entanglement in terms of molecular parameters and we find
that our predictions accord with recent experimental correlations relating
chain molecular structure to the entanglement molecular mass


title:
On positivity and semistability of vector bundles in finite and mixed
  characteristics

abstract:
  We survey results concerning behavior of positivity of line bundles and
possible vanishing theorems in positive characteristic. We also try to describe
variation of positivity in mixed characteristic. These problems are very much
related to behavior of strong semistability of vector bundles, which is another
main topic of the paper.


title: On the logical depth function

abstract:
  For a finite binary string $x$ its logical depth $d$ for significance $b$ is
the shortest running time of a program for $x$ of length $K(x)+b$. There is
another definition of logical depth. We give a new proof that the two versions
are close. There is an infinite sequence of strings of consecutive lengths such
that for every string there is a $b$ such that incrementing $b$ by 1 makes the
associated depths go from incomputable to computable. The maximal gap between
depths resulting from incrementing appropriate $b$'s by 1 is incomputable. The
size of this gap is upper bounded by the Busy Beaver function. Both the upper
and the lower bound hold for the depth with significance 0. As a consequence,
the minimal computation time of the associated shortest programs rises faster
than any computable function but not so fast as the Busy Beaver function.


title: Applications of the Stochastic LapH Method

abstract:
  Progress in computing the hadron spectrum in lattice QCD using stochastic
LapH quark propaga- tors is described. The stochastic LapH algorithm is a
particular quark smearing algorithm that also allows the computation of
all-to-all quark propagators. All-to-all quark propagators are required in our
approach of using a large set of spatially extended hadron operators and
explicit multi- particle operators to access excited states. We report on the
progress made in the various isospin channels on 2+1 dynamical, anisotropic
lattices generated by the Hadron Spectrum Collaboration.


title:
Habitable Planets Eclipsing Brown Dwarfs: Strategies for Detection and
  Characterization

abstract:
  Given the very close proximity of their habitable zones, brown dwarfs
represent high-value targets in the search for nearby transiting habitable
planets that may be suitable for follow-up occultation spectroscopy. In this
paper we develop search strategies to find habitable planets transiting brown
dwarfs depending on their maximum habitable orbital period (PHZ out). Habitable
planets with PHZ out shorter than the useful duration of a night (e.g. 8-10
hrs) can be screened with 100 percent completeness from a single location and
in a single night (near-IR). More luminous brown dwarfs require continuous
monitoring for longer duration, e.g. from space or from a longitude-distributed
network (one test scheduling achieved - 3 telescopes, 13.5 contiguous hours).
Using a simulated survey of the 21 closest known brown dwarfs (within 7 pc) we
find that the probability of detecting at least one transiting habitable planet
is between 4.5 +5.6-1.4 and 56 +31-13 percent, depending on our assumptions. We
calculate that brown dwarfs within 5-10 pc are characterizable for potential
biosignatures with a 6.5 m space telescope using approx. 1 percent of a 5-year
mission's life-time spread over a contiguous segment only one fifth to one
tenth of this duration.


title: Generalization of exotic quark searches

abstract:
  General limits on exotic heavy quarks T, B and X with masses above 300 GeV
are presented for arbitrary branching fractions of T=>Wb, T=>Zt, T=>Ht, B=>Wt,
B=>Zb, B=>Hb and X=>Wt. The results are based on a CMS search in final states
with three isolated leptons (electron or muon) or two isolated leptons with the
same electric charge. Exotic heavy quark pair production through the strong
interaction is considered. In the context of vector-like quark models, T quarks
with a mass mT < 480 GeV and mT < 550 GeV are excluded for weak isospin
singlets and doublets, respectively, and B quarks with a mass mB < 480 GeV are
excluded for singlets, all at 95% confidence level. Mass limits at 95%
confidence level for T and B singlets, (T,B) doublets and (X,T) doublets are
presented as a function of the corresponding heavy quark masses. For equal mass
mT = mB and mX = mT vector-like quarks are excluded at 95% confidence level
with masses below 550 GeV for T and B singlets, 640 GeV for a (T,B) doublet and
640 GeV for a (X,T) doublet.


title:
The QED contribution to $J/\psi$ plus light hadrons production at
  B-factories

abstract:
  To understand the direct $J/\psi+X_{\mathrm{non-c\bar{c}}}$ production
mechanism in $e^{+}e^{-}$ annihilation, in this work, we propose to measure the
inclusive $J/\psi$ plus light hadrons (LH) production at B-factories and
present a detailed study on its QED production due to $\psi(2S)$ feed-down,
where the $\psi(2S)$ are produced in $e^{+}e^{-}\to \psi(2S)+\gamma$ and
$e^{+}e^{-}\to \psi(2S)+f\bar{f}, f=lepton,light quark$, and QED contribution
to direct $J/\psi+q\bar{q}$ production with $q=u,d,s$ quark. We find that the
QED contribution is huge in the whole phase space region, but can be reduced
largely and is in the same order as the QCD contribution when a suitable cut on
the angel $\theta_{J/\psi}$ between $J/\psi$ and the $e^{+}e^{-}$ beam is made.
In this way, the cross section of $J/\psi+LH$ QCD production %which was
predicted theoretical at next-to-leading order QCD together with relativistic
correction, can be obtained by subtracting the QED contribution from the
experimental measurement on inclusive $J/\psi$ plus light hadrons. To help to
remove the QED background, we also calculate the angular and momentum
distribution of $J/\psi$ in the QED contribution.


title: Pretangent spaces with nonpositive and nonnegative Aleksandrov curvature

abstract:
  We find conditions under which the pretangent spaces to general metric spaces
have the nonpositive Aleksandrov curvature or nonnegative one. The
infinitesimal structure of general metric cpaces with Busemann convex
pretangent spaces is also described.


title:
Odd spin glueball masses and the odderon Regge trajectories from the
  holographic hardwall model

abstract:
  We use the holographic hardwall model to calculate the masses of light
glueball states with odd spin and P= C= -1 associated with odderons.
Considering Dirichlet and Neumann boundary conditions we obtain expressions for
the odderon Regge trajectories consistent with those calculated using other
approaches.


title:
Probing Correlations, Indistinguishability and Entanglement in Microwave
  Two-Photon Interference

abstract:
  Interference at a beam splitter reveals both classical and quantum properties
of electromagnetic radiation. When two indistinguishable single photons impinge
at the two inputs of a beam splitter they coalesce into a pair of photons
appearing in either one of its two outputs. This effect is due to the bosonic
nature of photons and was first experimentally observed by Hong, Ou, and Mandel
(HOM) [1]. Here, we present the observation of the HOM effect with two
independent single-photon sources in the microwave frequency domain. We probe
the indistinguishability of single photons, created with a controllable delay,
in time-resolved second-order cross- and auto-correlation function
measurements. Using quadrature amplitude detection we are able to resolve
different photon numbers and detect coherence in and between the output arms.
This measurement scheme allows us to observe the HOM effect and, in addition,
to fully characterize the two-mode entanglement of the spatially separated beam
splitter output modes. Our experiments constitute a first step towards using
two-photon interference at microwave frequencies for quantum communication and
information processing, e.g. for distributing entanglement between nodes of a
quantum network [2, 3] and for linear optics quantum computation [4, 5].


title:
Composition of simplicial complexes, polytopes and multigraded Betti
  numbers

abstract:
  For a simplicial complex K on m vertices and simplicial complexes K1,...,Km a
composed simplicial complex K(K1,...,Km) is introduced. This construction
generalizes an iterated simplicial wedge construction studied by A. Bahri, M.
Bendersky, F. R. Cohen and S. Gitler and allows to describe the combinatorics
of generalized joins of polytopes P(P1,...,Pm) defined by G. Agnarsson. The
composition defines a structure of an operad on a set of finite simplicial
complexes. We prove the following: (1) a composed complex K(K1,...,Km) is a
simplicial sphere iff K is a simplicial sphere and Ki are the boundaries of
simplices; (2) a class of spherical nerve-complexes is closed under the
operation of composition (3) finally, we express multigraded Betti numbers of
K(K1,...,Km) in terms of multigraded Betti numbers of K, K1,...,Km using a
composition of generating functions.


title: Orientation-dependent handedness and chiral design

abstract:
  Chirality occupies a central role in fields ranging from biological
self-assembly to the design of optical metamaterials. The definition of
chirality, as given by Lord Kelvin, associates chirality with the lack of
mirror symmetry: the inability to superpose an object on its mirror image.
While this definition has guided the classification of chiral objects for over
a century, the quantification of handed phenomena based on this definition has
proven elusive, if not impossible, as manifest in the paradox of chiral
connectedness. In this work, we put forward a quantification scheme in which
the handedness of an object depends on the direction in which it is viewed.
While consistent with familiar chiral notions, such as the right-hand rule,
this framework allows objects to be simultaneously right and left handed. We
demonstrate this orientation dependence in three different systems - a
biomimetic elastic bilayer, a chiral propeller, and optical metamaterial - and
find quantitative agreement with chirality pseudotensors whose form we
explicitly compute. The use of this approach resolves the existing paradoxes
and naturally enables the design of handed metamaterials from symmetry
principles.


title: Sure-Success Quantum Algorithms on Weight Decision Problem

abstract:
  Conditions on sure-success decidability of weights of Boolean functions are
presented for a given number of generalized Grover iterations. It is shown that
the decidability problem reduces to a system of algebraic equations of a single
variable. For problems that require a large number of iterations, it is
observed that the iteration number of sure-success quantum algorithms scale as
the square root of the iteration number of the corresponding classical
probabilistic algorithms. It is also demonstrated that for a few iterations,
quantum algorithms can be more efficient than this.


title: The quantum Rabi model for two qubits

abstract:
  We study the two-qubit Rabi model in the most general case where the qubits
are different from each other. The spectrum of the system in the
ultrastrong-coupling regime is shown to converge to two forced oscillator
chains by perturbation theory. An even and odd decomposition of the Hilbert
space allows us to calculate the spectra in any given parameter regime; the
cases studied confirm our perturbation theory prediction in the
ultrastrong-coupling regime and point to crossings in the spectra within each
parity subspace in the moderate-coupling regime. The normal modes of the system
are calculated by two different methods, the first a linear algebra approach
via the parity bases that delivers a four-term recurrence relation for the
amplitudes of the proper states and, the second, via Bargmann representation
for the field that delivers five-term recurrence relations. Finally, we show
some examples of the time evolution of the mean photon number, population
inversion, von Neuman entropy and Wootters concurrence under the two-qubit
quantum Rabi Hamiltonian by taking advantage of the parity decomposition.


title: Non-random overshoots of L\'evy processes

abstract:
  The class of Levy processes for which overshoots are almost surely constant
quantities is precisely characterized.


title: Compressive consolidation of strongly aggregated particle gels

abstract:
  The compressive yield stress of particle gels shows a highly nonlinear
dependence on the packing fraction. We have studied continuous compression
processes, and discussed the packing fraction dependence with the particle
scale rearrangements. The 2D simulation of uniaxial compression was applied to
fractal networks, and the required compressive stresses were evaluated for a
wide range of packing fractions that approached close packing. The compression
acts to reduce the size of the characteristic structural entities (i.e. the
correlation length of the structure). We observed three stages of compression:
(I) elastic-dominant regime; (II) single-mode plastic regime, where the network
strengths are determined by the typical length scale and the rolling mode; and
(III) multi-mode plastic regime, where sliding mode and connection breaks are
important. We also investigated the way of losing the fractal correlation under
compression. It turns out that both fractal dimension $D_{\mathrm{f}}$ and
correlation length $\xi$ start to change from the early stage of compression,
which is different from the usual assumption in theoretical models.


title:
New formulas for decreasing rearrangements and a class of Orlicz-Lorentz
  spaces

abstract:
  Using a nonlinear version of the well known Hardy-Littlewood inequalities, we
derive new formulas for decreasing rearrangements of functions and sequences in
the context of convex functions. We use these formulas for deducing several
properties of the modular functionals defining the function and sequence spaces
$M_{\varphi,w}$ and $m_{\varphi,w}$ respectively, introduced earlier in
\cite{HKM} for describing the K\"othe dual of ordinary Orlicz-Lorentz spaces in
a large variety of cases ($\varphi$ is an Orlicz function and $w$ a {\it
decreasing} weight). We study these $M_{\varphi,w}$ classes in the most general
setting, where they may even not be linear, and identify their K\"othe duals
with ordinary (Banach) Orlicz-Lorentz spaces. We introduce a new class of
rearrangement invariant Banach spaces $\mathcal{M}_{\varphi,w}$ which proves to
be the K\"othe biduals of the $M_{\varphi,w}$ classes. In the case when the
class $M_{\varphi,w}$ is a separable quasi-Banach space,
$\mathcal{M}_{\varphi,w}$ is its Banach envelope.


title:
Adiabatic stability under semi-strong interactions: The weakly damped
  regime

abstract:
  We rigorously derive multi-pulse interaction laws for the semi-strong
interactions in a family of singularly-perturbed and weakly-damped
reaction-diffusion systems in one space dimension. Most significantly, we show
the existence of a manifold of quasi-steady N-pulse solutions and identify a
"normal-hyperbolicity" condition which balances the asymptotic weakness of the
linear damping against the algebraic evolution rate of the multi-pulses. Our
main result is the adiabatic stability of the manifolds subject to this normal
hyperbolicity condition. More specifically, the spectrum of the linearization
about a fixed N-pulse configuration contains essential spectrum that is
asymptotically close to the origin as well as semi-strong eigenvalues which
move at leading order as the pulse positions evolve. We characterize the
semi-strong eigenvalues in terms of the spectrum of an explicit N by N matrix,
and rigorously bound the error between the N-pulse manifold and the evolution
of the full system, in a polynomially weighted space, so long as the
semi-strong spectrum remains strictly in the left-half complex plane, and the
essential spectrum is not too close to the origin.


title: Effective Field Theory for Long Strings

abstract:
  In previous work we used magnetic SU(N) gauge theory with adjoint
representation Higgs scalars to describe the long distance quark-antiquark
interaction in pure Yang-Mills theory, and later to obtain an effective string
theory. The empirically determined parameters of the non-Abelian effective
theory yielded $Z_N$ flux tubes resembling those of the Abelian Higgs model
with Landau-Ginzburg parameter equal to $ 1/\sqrt{2}$, corresponding to a
superconductor on the border between type I and type II. However, the physical
significance of the differences between the Abelian and the $Z_N$ vortices was
not elucidated and no principle was found to fix the value of the
'Landau-Ginzburg parameter' $\kappa$ of the non-Abelian theory determining the
structure of the $Z_N$ vortices. Here we reexamine this point of view. We
propose a consistency condition on $Z_N$ vortices underlying a confining
string. This fixes the value of $\kappa$. The transverse distribution of
pressure $p(r)$ in the resulting $Z_N$ flux tubes provides a physical picture
of these vortices which differs essentially from that of the vortices of the
Abelian Higgs model. We speculate that this general picture is valid
independent of the details of the effective magnetic gauge theory from which it
was obtained. Long wavelength fluctuations of the axis of the $Z_N$ vortices
lead from an effective field theory to an effective string theory with the
Nambu-Goto action. This effective string theory depends on a single parameter,
the string tension $\sigma$. In contrast, the effective field theory has a
second parameter, the intrinsic width 1/M of the flux tube.


title:
Interfacial roughening in non-ideal fluids: Dynamic scaling in the weak-
  and strong-damping regime

abstract:
  Interfacial roughening denotes the nonequilibrium process by which an
initially flat interface reaches its equilibrium state, characterized by the
presence of thermally excited capillary waves. Roughening of fluid interfaces
has been first analyzed by Flekkoy and Rothman [Phys. Rev. Lett. 75, 260
(1995)], where the dynamic scaling exponents in the weakly damped case in two
dimensions were found to agree with the Kardar-Parisi-Zhang universality class.
We extend this work by taking into account also the strong-damping regime and
perform extensive fluctuating hydrodynamics simulations in two dimensions using
the Lattice Boltzmann method. We show that the dynamic scaling behavior is
different in the weakly and strongly damped case.


title:
Production of $c \bar c c \bar c$ in double-parton scattering within
  $k_{t}$-factorization approach -- meson-meson correlations

abstract:
  We discuss production of two pairs of $c \bar c$ in proton-proton collisions
at the LHC. Both double-parton scattering (DPS) and single-parton scattering
(SPS) contributions are included in the analysis. Each step of DPS is
calculated within $k_t$-factorization approach, i.e. effectively including
next-to-leading order corrections. The conditions how to identify the DPS
contribution are presented. The discussed mechanism unavoidably leads to the
production of pairs of mesons: $D_i D_j$ (each containing $c$ quarks) or $\bar
D_i \bar D_j$ (each containing $\bar c$ antiquarks). We calculate corresponding
production rates for different combinations of charmed mesons as well as some
differential distribution for $(D^0 D^0$ + $\bar D^0 \bar D^0)$ production.
Within large theoretical uncertainties the predicted DPS cross section is
fairly similar to the cross section measured recently by the LHCb
collaboration. The best description is obtained with the Kimber-Martin-Ryskin
(KMR) unintegrated gluon distribution, which very well simulates higher-order
corrections. The contribution of SPS, calculated in the high-energy
approximation, turned out to be rather small. Finally, we emphasize significant
contribution of DPS mechanism to inclusive charmed meson spectra measured
recently by ALICE, ATLAS and LHCb.


title: High Multiplicity pp and pA Collisions: Hydrodynamics at its Edge

abstract:
  With growing multiplicity, the pp and pA collisions enter the domain where
the macroscopic description (thermodynamics and hydrodynamics) becomes
applicable. We discuss this situation, first with simplified thought
experiments, then with some idealized representative cases, and finally address
the real data. For clarity, we don't do it numerically but analytically, using
the Gubser solution. We found that the radial flow is expected to increase from
central AA to central pA, while the elliptic flow decreases, with higher
harmonics being comparable. In the second part of the paper we approach the
problem from the opposite side, using a string-based Pomeron model. We
extensively study the magnitude and distribution of the viscous corrections, in
Navier-Stokes and Israel-Stuart approximations, ending with higher gradient
re-summation proposed by Lublinsky and Shuryak. We found those corrections
growing, from AA to pA to pp, but remaining at the manageable size even in the
last case.


title:
Multi-photon nonclassical correlations in entangled squeezed vacuum
  states

abstract:
  Photon-number correlation measurements are performed on bright squeezed
vacuum states using a standard Bell-test setup, and quantum correlations are
observed for conjugate polarization-frequency modes. We further test the
entanglement witnesses for these states and demonstrate the violation of the
separability criteria, which infers that all the macroscopic Bell states,
containing typically $10^6$ photons per pulse, are polarization entangled. The
study also reveals the symmetry of macroscopic Bell states with respect to
local polarization transformations.


title:
Localized states in the conserved Swift-Hohenberg equation with cubic
  nonlinearity

abstract:
  The conserved Swift-Hohenberg equation with cubic nonlinearity provides the
simplest microscopic description of the thermodynamic transition from a fluid
state to a crystalline state. The resulting phase field crystal model describes
a variety of spatially localized structures, in addition to different spatially
extended periodic structures. The location of these structures in the
temperature versus mean order parameter plane is determined using a combination
of numerical continuation in one dimension and direct numerical simulation in
two and three dimensions. Localized states are found in the region of
thermodynamic coexistence between the homogeneous and structured phases, and
may lie outside of the binodal for these states. The results are related to the
phenomenon of slanted snaking but take the form of standard homoclinic snaking
when the mean order parameter is plotted as a function of the chemical
potential, and are expected to carry over to related models with a conserved
order parameter.


title: Super Efimov effect of resonantly interacting fermions in two dimensions

abstract:
  We study a system of spinless fermions in two dimensions with a short-range
interaction fine-tuned to a p-wave resonance. We show that three such fermions
form an infinite tower of bound states of orbital angular momentum l=\pm1 and
their binding energies obey a universal doubly exponential scaling
E_3^{(n)}\propto\exp(-2e^{3\pi n/4+\theta}) at large n. This "super Efimov
effect" is found by a renormalization group analysis and confirmed by solving
the bound state problem. We also provide an indication that there are l=\pm2
four-body resonances associated with every three-body bound state at
E_4^{(n)}\propto\exp(-2e^{3\pi n/4+\theta-0.188}). These universal few-body
states may be observed in ultracold atom experiments and should be taken into
account in future many-body studies of the system.


title: TAU2012 Summary

abstract:
  The main highlights discussed at TAU2012 are briefly summarized. Besides the
standard topics on lepton physics covered also at previous conferences
(universality, QCD tests, V_{us} determination from tau decay, g-2, neutrino
oscillations, lepton-flavour violation), the tau lepton is playing now a very
important role in searches for new physics phenomena.


title:
Characterization of the lack of compactness of $H^2_{rad}(\R^4)$ into
  the Orlicz space

abstract:
  This paper is devoted to the description of the lack of compactness of the
Sobolev space $H^2_{rad}(\R^4)$ in the Orlicz space $\mathcal{L}(\R^4)$. The
approach that we adopt to establish this characterization is in the spirit of
the one adopted in the case of $H^1_{rad}(\R^2)$ into the Orlicz space
$\mathcal{L}(\R^2)$ in \cite{Bahouri}.


title: Several transformation formulas for basic hypergeometric series

abstract:
  In 1981, Andrews gave a four-variable generalization of Ramanujan's
${_1\psi_1}$ summation formula. We establish a six-variable generalization of
Andrews' identity according to the transformation formula for two ${_8\phi_7}$
series and Bailey's transformation formula for three ${_8\phi_7}$ series. Then
it is used to find a six-variable generalization of Ramanujan's reciprocity
theorem, which is different from Liu's formula. We derive the generalizations
of Bailey's two $_3\psi_3$ summation formulas in terms of two limiting
relations and Bailey's another transformation formula for three $_8\phi_7$
series. Based on the two limiting relations, some different results involving
bilateral basic hypergeometric series are also deduced from the Guo--Schlosser
transformation formula and other two transformation formulas.


title:
VLT/XSHOOTER & Subaru/MOIRCS Spectroscopy of HUDF-YD3: No Evidence for
  Lyman-alpha Emission at z=8.55

abstract:
  We present spectroscopic observations with VLT/XSHOOTER and Subaru/MOIRCS of
a relatively bright Y-band drop-out galaxy in the Hubble Ultra Deep Field,
first selected by Bunker et al. (2010), McLure et al. (2010) and Bouwens et al.
(2010) to be a likely z~8-9 galaxy on the basis of its colours in the HST ACS
and WFC3 images. This galaxy, HUDF.YD3 (also known as UDFy-38135539) has been
targetted for VLT/SINFONI integral field spectroscopy by Lehnert et al. (2010),
who published a candidate Lyman-alpha emission line at z=8.55 from this source.
In our independent spectroscopy using two different infrared spectrographs (5
hours with VLT/XSHOOTER and 11 hours with Subaru/MOIRCS) we are unable to
reproduce this line. We do not detect any emission line at the spectral and
spatial location reported in Lehnert et al. (2010), despite the expected signal
in our combined MOIRCS & XSHOOTER data being 5-sigma. The line emission also
seems to be ruled out by the faintness of this object in recently extremely
deep F105W (Y-band) HST/WFC3 imaging from HUDF12; the line would fall within
this filter and such a galaxy should have been detected at Y(AB)=28.6mag (~20
sigma) rather than the marginal Y(AB)~30mag observed in the Y-band image, >3
times fainter than would be expected if the emission lie was real. Hence it
appears highly unlikely that the reported Lyman-alpha line emission at z>8 is
real, meaning that the highest-redshift sources for which Lyman-alpha emission
has been seen are at z=6.9-7.2. It is conceivable that Lyman-alpha does not
escape galaxies at higher redshifts, where the Gunn-Peterson absorption renders
the Universe optically thick to this line. However, deeper spectroscopy on a
larger sample of candidate z>7 galaxies will be needed to test this.


title:
Local-Search based Approximation Algorithms for Mobile Facility Location
  Problems

abstract:
  We consider the {\em mobile facility location} (\mfl) problem. We are given a
set of facilities and clients located in a common metric space. The goal is to
move each facility from its initial location to a destination and assign each
client to the destination of some facility so as to minimize the sum of the
movement-costs of the facilities and the client-assignment costs. This
abstracts facility-location settings where one has the flexibility of moving
facilities from their current locations to other destinations so as to serve
clients more efficiently by reducing their assignment costs.
  We give the first {\em local-search based} approximation algorithm for this
problem and achieve the best-known approximation guarantee. Our main result is
$(3+\epsilon)$-approximation for this problem for any constant $\epsilon>0$
using local search. The previous best guarantee was an 8-approximation
algorithm based on LP-rounding. Our guarantee {\em matches} the best-known
approximation guarantee for the $k$-median problem. Since there is an
approximation-preserving reduction from the $k$-median problem to \mfl, any
improvement of our result would imply an analogous improvement for the
$k$-median problem. Furthermore, {\em our analysis is tight} (up to $o(1)$
factors) since the tight example for the local-search based 3-approximation
algorithm for $k$-median can be easily adapted to show that our local-search
algorithm has a tight approximation ratio of 3. One of the chief novelties of
the analysis is that in order to generate a suitable collection of local-search
moves whose resulting inequalities yield the desired bound on the cost of a
local-optimum, we define a tree-like structure that (loosely speaking)
functions as a "recursion tree", using which we spawn off local-search moves by
exploring this tree to a constant depth.


title: Vortical and Self-similar Flows of 2D Compressible Euler Equations

abstract:
  This paper presents the vortical and self-similar solutions for 2D
compressible Euler equations using the separation method. These solutions
complement Makino's solutions in radial symmetry without rotation. The
rotational solutions provide new information that furthers our understanding of
ocean vortices and reference examples for numerical methods. In addition, the
corresponding blowup, time-periodic or global existence conditions are
classified through an analysis of the new Emden equation. A conjecture
regarding rotational solutions in 3D is also made.


title:
Deformations of complex structures and the coupled K\"ahler-Yang-Mills
  equations

abstract:
  In this work we define a deformation theory for the Coupled
K\"ahler-Yang-Mills equations in arXiv:1102.0991, generalizing work of
Sz\'ekelyhidi on constant scalar curvature K\"ahler metrics. We use the theory
to find new solutions of the equations via deformation of the complex structure
of a polarised manifold endowed with a holomorphic vector bundle. We also study
the deformations of the recent examples of Keller and T{\o}nnesen-Friedman.


title: Clustering and Uncertainty in Perfect Chaos Systems

abstract:
  The goal of this investigation was to derive strictly new properties of
chaotic systems and their mutual relations. The generalized Fokker-Planck
equation with a non stationary diffusion has been derived and used for chaos
analysis. An anomalous transport turned out to be natural property of this
equation. A nonlinear dispersion of the considered motion allowed to find a
principal consequence: a chaotic system with uniform dynamic properties tends
to unstable clustering. Small fluctuations of particles density increase by
time and form attractors and stochastic islands even if the initial transport
properties have uniform distribution. It was shown that an instability of phase
trajectories leads to the nonlinear dispersion law and consequently to a space
instability. A fixed boundary system was considered, using a standard
Fokker-Planck equation. We have derived that such a type of dynamic systems has
a discrete diffusive and energy spectra. It was shown that phase space
diffusion is the only parameter that defines a dynamic accuracy in this case.
The uncertainty relations have been obtained for conjugate phase space
variables with account of transport properties. Given results can be used in
the area of chaotic systems modelling and turbulence investigation.


title:
One-Dimensional Potential Model for Image States on Free-Standing
  Graphene

abstract:
  In the framework of the non-local dielectric theory the static non-local
self-energy of an electron near an ultra-thin polarizable layer has been
calculated and applied to study image-states near free-standing graphene. The
corresponding series of eigenvalues and eigenfunctions have been obtained by
solving numerically the one-dimensional Schr{\"o}dinger equation. We compare
with the Rydgberg's series for a perfect metal and with experimental values
measured on graphene layers grown on Ir and Ru surfaces. For free standing
films, the appearance of states with binding energies in between the classical
series is discussed.


title:
Casadio-Fabbri-Mazzacurati Black Strings and Braneworld-induced Quasars
  Luminosity Corrections

abstract:
  This paper aims to evince the corrections on the black string warped horizon
in the braneworld paradigm, and their drastic physical consequences, as well as
to provide subsequent applications in astrophysics. Our analysis concerning
black holes on the brane departs from the Schwarzschild case, where the black
string is unstable to large-scale perturbation. The cognizable measurability of
the black string horizon corrections due to braneworld effects is investigated,
as well as their applications in the variation of quasars luminosity. We delve
into the case wherein two solutions of Einstein's equations proposed by
Casadio, Fabbri, and Mazzacurati, regarding black hole metrics presenting a
post-Newtonian parameter measured on the brane. In this scenario, it is
possible to analyze purely the braneworld corrected variation in quasars
luminosity, by an appropriate choice of the post-Newtonian parameter that
precludes Hawking radiation on the brane: the variation in quasars luminosity
is uniquely provided by pure braneworld effects, as the Hawking radiation on
the brane is suppressed.


title: Hofer geometry and cotangent fibers

abstract:
  For a class of Riemannian manifolds that include products of arbitrary
compact manifolds with manifolds of nonpositive sectional curvature on the one
hand, or with certain positive-curvature examples such as spheres of dimension
at least 3 and compact semisimple Lie groups on the other, we show that the
Hamiltonian diffeomorphism group of the cotangent bundle contains as subgroups
infinite-dimensional normed vector spaces that are bi-Lipschitz embedded with
respect to Hofer's metric; moreover these subgroups can be taken to consist of
diffeomorphisms supported in an arbitrary neighborhood of the zero section. In
fact, the orbit of a fiber of the cotangent bundle with respect to any of these
subgroups is quasi-isometrically embedded with respect to the induced Hofer
metric on the orbit of the fiber under the whole group. The diffeomorphisms in
these subgroups are obtained from reparametrizations of the geodesic flow. Our
proofs involve a study of the Hamiltonian-perturbed Floer complex of a pair of
cotangent fibers (or, more generally, of a conormal bundle together with a
cotangent fiber). Although the homology of this complex vanishes, an analysis
of its boundary depth yields the lower bounds on the Lagrangian Hofer metric
required for our main results.


title: Bousfield lattices of non-Noetherian rings: some quotients and products

abstract:
  In the context of a well generated tensor triangulated category, Section 3
investigates the relationship between the Bousfield lattice of a quotient and
quotients of the Bousfield lattice. In Section 4 we develop a general framework
to study the Bousfield lattice of the derived category of a commutative or
graded-commutative ring, using derived functors induced by extension of
scalars. Section 5 applies this work to extend results of Dwyer and Palmieri
[DP08] to new non-Noetherian rings.


title: Nonstandard approach to gravity for the dark sector of the Universe

abstract:
  We summarize the present state of research on the darkon fuid as a model for
the dark sector of the Universe. Nonrelativistic massless particles are
introduced as a realization of the Galilei group in an enlarged phase space.
The additional degrees of freedom allow for a nonstandard, minimal coupling to
gravity respecting Einstein's equivalence principle. Extended to a
self-gravitating fluid the Poisson equation for the gravitational potential
contains a dynamically generated effective gravitational mass density of either
sign. The equations of motion (EOMs) contain no free parameters and are
invariant w.r.t. Milne gauge transformations. Fixing the gauge eliminates the
unphysical degrees of freedom. The resulting Lagrangian possesses no free
particle limit. The particles it describes, darkons, exist only as fluid
particles of a self-gravitating fluid. This darkon fluid realizes the zero-mass
Galilean algebra extended by dilations with dynamical exponent z = 5/3. We
reduce the EOMs to Friedmann-like equations, derive conserved quantities and a
unique Hamiltonian dynamics by implementing dilation symmetry. By the Casimir
of the Poisson-bracket (PB)-algebra we foliate the phase space and construct a
Lagrangian in reduced phase space. We solve the Friedmann-like equations with
the transition redshift and the value of the Casimir as integration constants.
We obtain a deceleration phase for the early Universe and an acceleration phase
for the late Universe in agreement with observations. Steady state equations in
the spherically symmetric case may model a galactic halo. Numerical solutions
of a nonlinear differential equation for the gravitational potential lead to
predictions for the dark matter (DM) part of the rotation curves (RCs) of
galaxies in qualitative agreement with observational data. We also present a
general covariant generalization of the model.


title:
Unusual persistence of superconductivity against high magnetic fields in
  the strongly-correlated iron-chalcogenide film FeTe:O$_{x}$

abstract:
  We report an unusual persistence of superconductivity against high magnetic
fields in the iron chalcogenide film FeTe:O$_{x}$ below ~ 2.5 K. Instead of
saturating like a mean-field behavior with a single order parameter, the
measured low-temperature upper critical field increases progressively,
suggesting a large supply of superconducting states accessible via magnetic
field or low-energy thermal fluctuations. We demonstrate that superconducting
states of finite momenta can be realized within the conventional theory,
despite its questionable applicability. Our findings reveal a fundamental
characteristic of superconductivity and electronic structure in the
strongly-correlated iron-based superconductors.


title: Twisted Bilayer Graphene Superlattices

abstract:
  Twisted bilayer graphene (tBLG) provides us with a large rotational freedom
to explore new physics and novel device applications, but many of its basic
properties remain unresolved. Here we report the synthesis and systematic Raman
study of tBLG. Chemical vapor deposition was used to synthesize hexagon- shaped
tBLG with a rotation angle that can be conveniently determined by relative edge
misalignment. Superlattice structures are revealed by the observation of two
distinctive Raman features: folded optical phonons and enhanced intensity of
the 2D-band. Both signatures are strongly correlated with G-line resonance,
rotation angle and laser excitation energy. The frequency of folded phonons
decreases with the increase of the rotation angle due to increasing size of the
reduced Brillouin zone (rBZ) and the zone folding of transverse optic (TO)
phonons to the rBZ of superlattices. The anomalous enhancement of 2D-band
intensity is ascribed to the constructive quantum interference between two
Raman paths enabled by a near-degenerate Dirac cone. The fabrication and Raman
identification of superlattices pave the way for further basic study and new
applications of tBLG.


title:
Numerically exact, time-dependent study of correlated electron transport
  in model molecular junctions

abstract:
  The multilayer multiconfiguration time-dependent Hartree theory within second
quantization representation of the Fock space is applied to study correlated
electron transport in models of single-molecule junctions. Extending previous
work, we consider models which include both electron-electron and
electronic-vibrational interaction. The results show the influence of the
interactions on the transient and the stationary electrical current. The
underlying physical mechanisms are analyzed in conjunction with the
nonequilibrium electronic population of the molecular bridge.


title:
Regional Consistency: Programmability and Performance for
  Non-Cache-Coherent Systems

abstract:
  Parallel programmers face the often irreconcilable goals of programmability
and performance. HPC systems use distributed memory for scalability, thereby
sacrificing the programmability advantages of shared memory programming models.
Furthermore, the rapid adoption of heterogeneous architectures, often with
non-cache-coherent memory systems, has further increased the challenge of
supporting shared memory programming models. Our primary objective is to define
a memory consistency model that presents the familiar thread-based shared
memory programming model, but allows good application performance on
non-cache-coherent systems, including distributed memory clusters and
accelerator-based systems. We propose regional consistency (RegC), a new
consistency model that achieves this objective. Results on up to 256 processors
for representative benchmarks demonstrate the potential of RegC in the context
of our prototype distributed shared memory system.


title: Strained Layer Crystalline Undulator

abstract:
  Ultrarelativistic charged particles are predicted to emit hard
electromagnetic radiation of undulator type while being channeled in a crystal
with periodically bent crystallographic planes. The recently proposed
crystalline undulator with the bending amplitude smaller than the distance
between the bent planes and the bending period shorter than the period of
channeling oscillations is far superior to what was proposed previously. In the
same time, it is more challenging from the technical point of view because its
bending period has to be in the sub-micron range. It is shown that a mixed
crystal of silicon-germanium with properly varying germanium fraction can have
the necessary bending parameters. Moreover, it is predicted to be stable
against misfit dislocations.


title:
Constructing gapless spin liquid state for the spin-1/2 J1-J2 Heisenberg
  model on a square lattice

abstract:
  We construct a class of projected entangled pair states (PEPS) which is
exactly the resonating valence bond (RVB) wavefunctions endowed with both short
range and long range valence bonds. With an energetically preferred RVB
pattern, the wavefunction is simplified to live in a one parameter variational
space. We tune this variational parameter to minimize the energy for the
frustrated spin 1/2 J1-J2 antiferromagnetic Heisenberg model on the square
lattice. Taking a cylindrical geometry, we are able to construct four
topological sectors with even or odd number of fluxes penetrating the cylinder
and even or odd number of spinons on the boundary. The energy splitting in
different topological sectors is exponentially small with the cylinder
perimeter. We find a power law decay of the dimer correlation function on a
torus, and a lnL correction to the entanglement entropy, indicating a gapless
spin liquid phase at the optimum parameter.


title:
Comment on "Proximity breakdown of hydrides in superconducting niobium
  cavities" [arXiv:1212.3384]

abstract:
  Comment on Proximity breakdown of hydrides in superconducting niobium
cavities [arXiv:1212.3384].


title: DiracQ: A Quantum Many-Body Physics Package

abstract:
  We present a software package DiracQ, for use in quantum many-body Physics.
It is designed for helping with typical algebraic manipulations that arise in
quantum Condensed Matter Physics and Nuclear Physics problems, and also in some
subareas of Chemistry. DiracQ is invoked within a Mathematica session, and
extends the symbolic capabilities of Mathematica by building in standard
commutation and anticommutation rules for several objects relevant in many-body
Physics. It enables the user to carry out computations such as evaluating the
commutators of arbitrary combinations of spin, Bose and Fermi operators defined
on a discrete lattice, or the position and momentum operators in the continuum.
Some examples from popular systems, such as the Hubbard model, are provided to
illustrate the capabilities of the package.

categories: cond-mat.str-el hep-th math-ph math.MP nucl-th


title:
Collapse and Fragmentation of Magnetic Molecular Cloud Cores with the
  Enzo AMR MHD Code. I. Uniform Density Sphere

abstract:
  Magnetic fields are important contributers to the dynamics of collapsing
molecular cloud cores, and can have a major effect on whether collapse results
in a single protostar or fragmentation into a binary or multiple protostar
system. New models are presented of the collapse of magnetic cloud cores using
the adaptive mesh refinement (AMR) code Enzo2.0. The code was used to calculate
the ideal magnetohydrodynamics (MHD) of initially spherical, uniform density
and rotation clouds with density perturbations, i.e., the Boss and Bodenheimer
(1979) standard isothermal test case for three dimensional (3D) hydrodynamics
(HD) codes. After first verifying that Enzo reproduces the binary fragmentation
expected for the non-magnetic test case, a large set of models was computed
with varied initial magnetic field strengths and directions with respect to the
cloud core axis of rotation (parallel or perpendicular), density perturbation
amplitudes, and equations of state. Three significantly different outcomes
resulted: (1) contraction without sustained collapse, forming a denser cloud
core, (2) collapse to form a single protostar with significant spiral arms, and
(3) collapse and fragmentation into binary or multiple protostar systems, with
multiple spiral arms. Comparisons are also made with previous MHD calculations
of similar clouds with barotropic equations of state. These results for the
collapse of initially uniform density spheres illustrate the central importance
of both magnetic field direction and field strength for determining the outcome
of dynamic protostellar collapse.


title: Panchromatic spectral energy distributions of Herschel sources

abstract:
  (abridged) Far-infrared Herschel photometry from the PEP and HerMES programs
is combined with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields.
Based on this rich dataset, we reproduce the restframe UV to FIR ten-colors
distribution of galaxies using a superposition of multi-variate Gaussian modes.
The median SED of each mode is then fitted with a modified version of the
MAGPHYS code that combines stellar light, emission from dust heated by stars
and a possible warm dust contribution heated by an AGN. The defined Gaussian
grouping is also used to identify rare sources. The zoology of outliers
includes Herschel-detected ellipticals, very blue z~1 Ly-break galaxies,
quiescent spirals, and torus-dominated AGN with star formation. Out of these
groups and outliers, a new template library is assembled, consisting of 32 SEDs
describing the intrinsic scatter in the restframe UV-to-submm colors of
infrared galaxies. This library is tested against L(IR) estimates with and
without Herschel data included, and compared to eight other popular methods
often adopted in the literature. When implementing Herschel photometry, these
approaches produce L(IR) values consistent with each other within a median
absolute deviation of 10-20%, the scatter being dominated more by fine tuning
of the codes, rather than by the choice of SED templates. Finally, the library
is used to classify 24 micron detected sources in PEP GOODS fields. AGN appear
to be distributed in the stellar mass (M*) vs. star formation rate (SFR) space
along with all other galaxies, regardless of the amount of infrared luminosity
they are powering, with the tendency to lie on the high SFR side of the "main
sequence". The incidence of warmer star-forming sources grows for objects with
higher specific star formation rates (sSFR), and they tend to populate the
"off-sequence" region of the M*-SFR-z space.


title:
The Strikingly Similar Relation between Satellite and Central Galaxies
  and Their Dark Matter Halos Since z=2

abstract:
  Satellite galaxies in rich clusters are subject to numerous physical
processes that can significantly influence their evolution. However, the
typical L* satellite galaxy resides in much lower mass galaxy groups, where the
processes capable of altering their evolution are generally weaker and have had
less time to operate. To investigate the extent to which satellite and central
galaxy evolution differs, we separately model the stellar mass - halo mass (M*
-Mh) relation for these two populations over the redshift interval 0 < z < 1.
This relation for central galaxies is constrained by the galaxy stellar mass
function while the relation for satellite galaxies is constrained against
recent measurements of the galaxy two-point correlation function (2PCF). At z ~
0 the satellites, on average, have ~10% larger stellar masses at fixed peak
subhalo mass compared to central galaxies of the same halo mass. This is
required in order to reproduce the observed stellar mass-dependent 2PCF and
satellite fractions. At low masses our model slightly under-predicts the
correlation function at ~1 Mpc scales. At z ~ 1 the satellite and central
galaxy M*-Mh relations are consistent within the errors, and the model provides
an excellent fit to the clustering data. At present, the errors on the
clustering data at z ~ 2 are too large to constrain the satellite model. A
simple model in which satellite and central galaxies share the same M*-Mh
relation is able to reproduce the extant z ~ 2 clustering data. We speculate
that the striking similarity between the satellite and central galaxy M*-Mh
relations since z ~ 2 arises because the central galaxy relation evolves very
weakly with time and because the stellar mass of the typical satellite galaxy
has not changed significantly since it was accreted. [Abridged]


title: Nyx: A Massively Parallel AMR Code for Computational Cosmology

abstract:
  We present a new N-body and gas dynamics code, called Nyx, for large-scale
cosmological simulations. Nyx follows the temporal evolution of a system of
discrete dark matter particles gravitationally coupled to an inviscid ideal
fluid in an expanding universe. The gas is advanced in an Eulerian framework
with block-structured adaptive mesh refinement (AMR); a particle-mesh (PM)
scheme using the same grid hierarchy is used to solve for self-gravity and
advance the particles. Computational results demonstrating the validation of
Nyx on standard cosmological test problems, and the scaling behavior of Nyx to
50,000 cores, are presented.


title:
NIFTY - Numerical Information Field Theory - a versatile Python library
  for signal inference

abstract:
  NIFTY, "Numerical Information Field Theory", is a software package designed
to enable the development of signal inference algorithms that operate
regardless of the underlying spatial grid and its resolution. Its
object-oriented framework is written in Python, although it accesses libraries
written in Cython, C++, and C for efficiency. NIFTY offers a toolkit that
abstracts discretized representations of continuous spaces, fields in these
spaces, and operators acting on fields into classes. Thereby, the correct
normalization of operations on fields is taken care of automatically without
concerning the user. This allows for an abstract formulation and programming of
inference algorithms, including those derived within information field theory.
Thus, NIFTY permits its user to rapidly prototype algorithms in 1D, and then
apply the developed code in higher-dimensional settings of real world problems.
The set of spaces on which NIFTY operates comprises point sets, n-dimensional
regular grids, spherical spaces, their harmonic counterparts, and product
spaces constructed as combinations of those. The functionality and diversity of
the package is demonstrated by a Wiener filter code example that successfully
runs without modification regardless of the space on which the inference
problem is defined.

categories: astro-ph.IM cs.IT cs.MS math-ph math.IT math.MP physics.data-an stat.CO


title: Accretion Does Not Drive the Turbulence in Galactic Disks

abstract:
  Rapid accretion of cold gas plays a crucial role in getting gas into
galaxies. It has been suggested that this accretion proceeds along narrow
streams that might also directly drive the turbulence in galactic gas,
dynamical disturbances, and bulge formation. In cosmological simulations,
however, it is impossible to isolate and hence disentangle the effect of
accretion from internal instabilities and mergers. Moreover, in most
cosmological simulations, the phase structure and turbulence in the ISM arising
from stellar feedback are treated in a sub-grid manner, so that feedback cannot
generate ISM turbulence. In this paper we therefore test the effects of cold
streams in extremely high-resolution simulations of otherwise isolated galaxy
disks using detailed models for star formation and feedback; we then include or
exclude mock cold flows falling onto the galaxies with accretion rates,
velocities and geometry set to maximize their effect on the disk. We find: (1)
Turbulent velocity dispersions in gas disks are identical with or without the
cold flow; the energy injected by the flow is dissipated where it meets the
disk. (2) In runs without stellar feedback, the presence of a cold flow has
essentially no effect on runaway local collapse, resulting in star formation
rates (SFRs) that are far too large. (3) Disks in runs with feedback and cold
flows have higher SFRs, but only insofar as they have more gas. (4) Because
flows are extended relative to the disk, they do not trigger strong resonant
responses and so induce weak morphological perturbation (bulge formation via
instabilities is not accelerated). (5) However, flows can thicken the disk by
direct contribution of out-of-plane streams. We conclude that while inflows are
critical over cosmological timescales to determine the supply and angular
momentum of gas disks, they have weak instantaneous dynamical effects on
galaxies.


title: All-Sky Analysis of the General Relativistic Galaxy Power Spectrum

abstract:
  We perform an all-sky analysis of the general relativistic galaxy power
spectrum using the well-developed spherical Fourier decomposition. Spherical
Fourier analysis expresses the observed galaxy fluctuation in terms of the
spherical harmonics and spherical Bessel functions that are angular and radial
eigenfunctions of the Helmholtz equation, providing a natural orthogonal basis
for all-sky analysis of the large-scale mode measurements. Accounting for all
the relativistic effects in galaxy clustering, we compute the spherical power
spectrum and its covariance matrix and compare it to the standard
three-dimensional power spectrum to establish a connection. The spherical power
spectrum recovers the three-dimensional power spectrum at each wavenumber k
with its angular dependence mu_k encoded in angular multipole l, and the
contributions of the line-of-sight projection to galaxy clustering such as the
gravitational lensing effect can be readily accommodated in the spherical
Fourier analysis. A complete list of formulas for computing the relativistic
spherical galaxy power spectrum is also presented.


title: The scale of soft resummation in SCET vs perturbative QCD

abstract:
  We summarize and extend previous results on the comparison of threshold
resummation, performed, using soft-collinear effective theory (SCET), in the
Becher-Neubert approach, to the standard perturbative QCD formalism based on
factorization and resummation of Mellin moments of partonic cross sections. We
show that the logarithmic accuracy of this SCET result can be extended by half
a logarithmic order, thereby bringing it in full agreement with the standard
QCD result if a suitable choice is made for the soft scale mu_s which
characterizes the SCET result. We provide a master formula relating the two
approaches for other scale choices. We then show that with the Becher-Neubert
scale choice the Landau pole, which in the perturbative QCD approach is usually
removed through power- or exponentially suppressed terms, in the SCET approach
is removed by logarithmically subleading terms which break factorization. Such
terms may become leading for generic choices of parton distributions, and are
always leading when resummation is used far enough from the hadronic threshold.


title:
Kepler's Optical Secondary Eclipse of HAT-P-7b and Probable Detection of
  Planet-Induced Stellar Gravity Darkening

abstract:
  We present observations spanning 355 orbital phases of HAT-P-7 observed by
Kepler from May 2009 to March 2011 (Q1-9). We find a shallower secondary
eclipse depth than initially announced, consistent with a low optical albedo
and detection of nearly exclusively thermal emission, without a reflected light
component. We find an approximately 10 ppm perturbation to the average transit
light curve near phase -0.02 that we attribute to a temperature decrease on the
surface of the star, phased to the orbit of the planet. This cooler spot is
consistent with planet-induced gravity darkening, slightly lagging the
sub-planet position due to the finite response time of the stellar atmosphere.
The brightness temperature of HAT-P-7b in the Kepler bandpass is T_B = 2733 +/-
21 K and the amplitude of the deviation in stellar surface temperature due to
gravity darkening is approximately -0.18 K. The detection of the spot is not
statistically unequivocal due its small amplitude, though additional Kepler
observations should be able to verify the astrophysical nature of the anomaly.


title: Quantum Computation vs. Firewalls

abstract:
  In this paper we discuss quantum computational restrictions on the types of
thought experiments recently used by Almheiri, Marolf, Polchinski, and Sully to
argue against the smoothness of black hole horizons. We argue that the quantum
computations required to do these experiments take a time which is exponential
in the entropy of the black hole under study, and we show that for a wide
variety of black holes this prevents the experiments from being done. We
interpret our results as motivating a broader type of non-locality than is
usually considered in the context of black hole thought experiments, and claim
that once this type of non-locality is allowed there may be no need for
firewalls. Our results do not threaten the unitarity of of black hole
evaporation or the ability of advanced civilizations to test it.


title: Black Hole Complementarity and the Harlow-Hayden Conjecture

abstract:
  Black hole complementarity, as originally formulated in the 1990's by
Preskill, 't Hooft, and myself is now being challenged by the
Almheiri-Marolf-Polchinski-Sully firewall argument. The AMPS argument relies on
an implicit assumption---the ``proximity postulate---which says that the
interior of a black hole must be constructed from degrees of freedom that are
physically near the black hole. The proximity postulate manifestly contradicts
the idea that interior information is redundant with information in Hawking
radiation, which is very far from the black hole. AMPS argue that a violation
of the proximity postulate would lead to a contradiction in a
thought-experiment in which Alice distills the Hawking radiation and brings a
bit back to the black hole. According to AMPS the only way to protect against
the contradiction is for a firewall to form at the Page time. But the
measurement that Alice must make, is of such a fine-grained nature that
carrying it out before the black hole evaporates may be impossible. Harlow and
Hayden have found evidence that the limits of quantum computation do in fact
prevent Alice from carrying out her experiment in less than exponential time.
If their conjecture is correct then black hole complementarity may be alive and
well.
  My aim here is to give an overview of the firewall argument, and its basis in
the proximity postulate; as well as the counterargument based on computational
complexity, as conjectured by Harlow and Hayden.


title:
Projection Methods: Swiss Army Knives for Solving Feasibility and Best
  Approximation Problems with Halfspaces

abstract:
  We model a problem motivated by road design as a feasibility problem.
Projections onto the constraint sets are obtained, and projection methods for
solving the feasibility problem are studied. We present results of numerical
experiments which demonstrate the efficacy of projection methods even for
challenging nonconvex problems.


title: Search for the rare decay Bs->mumu

abstract:
  We perform a search for the rare decay Bs->mumu using data collected by the
D0 experiment at the Fermilab Tevatron Collider. This result is based on the
full D0 Run II dataset corresponding to 10.4 fb^(-1) of ppbar collisions at
sqrt(s) = 1.96 TeV. We use a multivariate analysis to increase the sensitivity
of the search. In the absence of an observed number of events above the
expected background, we set an upper limit on the decay branching fraction of
BR(Bs->mumu) < 15x10^(-9) at the 95% C.L.


title:
Comment on "Z2-slave-spin theory for strongly correlated fermions" +
  Reply to the Reply to the "Comment on ?Z2-slave-spin theory for strongly
  correlated" fermions?

abstract: We discusss the results published by Ruegg et al in PRB 81, 155118 (2010).


title:
Improved nanopatterning for YBCO nanowires approaching the depairing
  current

abstract:
  An improved nanopatterning procedure has been developed to obtain YBCO
nanowires with cross sections as small as 50x50 nm^2, protected by an Au
capping layer. To probe the effective role of the Au protecting layer, we have
measured the current-voltage characteristics and the resistive transition in
temperature of the nanowires. Critical current densities up to 10^8 A/cm^2 have
been achieved at T=4.2 K, approaching the theoretical depairing current limit.
The resistance, measured as a function of temperature close to Tc, has been
fitted with a thermal activated phase slip model, including the effect of the
gold layer. The extracted values of the superconducting coherence length and of
the London penetration depth give current densities consistent with the
measured ones. These results cannot be achieved with same nanowires, without
the Au capping layer.


title: Geometric nullstellensatz and symbolic powers on arbitrary varieties

abstract:
  In recent years, a multiplier ideal defined on arbitrary varieties, so called
Mather multiplier ideal, has been developed independently by Ein-Ishii-Mustata,
and de Fernex-Docampo. With this new tool, we have a chance of extending some
classical results proved in nonsingular case to arbitrary varieties to
establish their general forms. In this paper, we first extend a result of
geometric nullstellensatz due to Ein-Lazarsfeld in nonsingular case to any
projective varieties. Then we prove a result on comparison of symbolic powers
with ordinary powers on any varieties, which extends results of
Ein-Lazarsfeld-Smith and Hochster-Huneke.


title:
Separation of the largest eigenvalues in eigenanalysis of genotype data
  from discrete subpopulations

abstract:
  We present a mathematical model, and the corresponding mathematical analysis,
that justifies and quantifies the use of principal component analysis of
biallelic genetic marker data for a set of individuals to detect the number of
subpopulations represented in the data. We indicate that the power of the
technique relies more on the number of individuals genotyped than on the number
of markers.


title:
Asymmetry-induced effects in Kondo quantum dots coupled to ferromagnetic
  leads

abstract:
  We study the spin-resolved transport through single-level quantum dots
strongly coupled to ferromagnetic leads in the Kondo regime, with a focus on
contact and material asymmetry-related effects. By using the numerical
renormalization group method, we analyze the dependence of relevant spectral
functions, linear conductance and tunnel magnetoresistance on the system
asymmetry parameters. In the parallel magnetic configuration of the device the
Kondo effect is generally suppressed due to the presence of exchange field,
irrespective of system's asymmetry. In the antiparallel configuration, on the
other hand, the Kondo effect can develop if the system is symmetric. We show
that even relatively weak asymmetry may lead to the suppression of the Kondo
resonance in the antiparallel configuration and thus give rise to nontrivial
behavior of the tunnel magnetoresistance. In addition, by using the
second-order perturbation theory we derive general formulas for the exchange
field in both magnetic configurations of the system.


title:
Current induced torques and interfacial spin-orbit coupling:
  Semiclassical Modeling

abstract:
  In bilayer nanowires consisting of a ferromagnetic layer and a non-magnetic
layer with strong spin-orbit coupling, currents create torques on the
magnetization beyond those found in simple ferromagnetic nanowires. The
resulting magnetic dynamics appear to require torques that can be separated
into two terms, damping-like and field-like. The damping-like torque is
typically derived from models describing the bulk spin Hall effect and the spin
transfer torque, and the field-like torque is typically derived from a Rashba
model describing interfacial spin-orbit coupling. We derive a model based on
the Boltzmann equation that unifies these approaches. We also consider an
approximation to the Boltzmann equation, the drift-diffusion model, that
qualitatively reproduces the behavior, but quantitatively fails to reproduce
the results. We show that the Boltzmann equation with physically reasonable
parameters can match the torques for any particular sample, but in some cases,
it fails to describe the experimentally observed thickness dependences.


title: Perturbations of basic Dirac operators on Riemannian foliations

abstract:
  Using the method of Witten deformation, we express the basic index of a
transversal Dirac operator over a Riemannian foliation as the sum of integers
associated to the critical leaf closures of a given foliated bundle map.


title:
$|V_{cd}|$ and $|V_{cs}|$ from Semileptonic and Leptonic decays using
  lattice QCD methods

abstract:
  In this paper, we review recent calculations of the CKM matrix elements
$|V_{cd}|$ and $|V_{cs}|$ from semileptonic and leptonic decays of $D$ and
$D_s$ mesons using lattice QCD methods.


title:
Transcript length mediates developmental timing of gene expression
  across Drosophila

abstract:
  The time required to transcribe genes with long primary transcripts may limit
their ability to be expressed in cells with short mitotic cycles, a phenomenon
termed intron delay. As such short cycles are a hallmark of the earliest stages
of insect development, we used Drosophila developmental timecourse expression
data to test whether intron delay affects gene expression genome-wide, and to
determine its consequences for the evolution of gene structure. We find that
long zygotically expressed, but not maternally deposited, genes show
substantial delay in expression relative to their shorter counterparts and that
this delay persists over a substantial portion of the ~24 hours of
embryogenesis. Patterns of RNA-seq coverage from the 5' and 3' ends of
transcripts show that this delay is consistent with their inability to
terminate transcription, but not with transcriptional initiation-based
regulatory control. Highly expressed zygotic genes are subject to purifying
selection to maintain compact transcribed regions, allowing conservation of
embryonic expression patterns across the Drosophila phylogeny. We propose that
intron delay is an underappreciated physical mechanism affecting both patterns
of expression as well as gene structure of many genes across Drosophila.


title: Halo orbits in cosmological disk galaxies: tracers of formation history

abstract:
  We analyze the orbits of stars and dark matter particles in the halo of a
disk galaxy formed in a cosmological hydrodynamical simulation. The halo is
oblate within the inner ~20 kpc and triaxial beyond this radius. About 43% of
orbits are short axis tubes - the rest belong to orbit families that
characterize triaxial potentials (boxes, long-axis tubes and chaotic orbits),
but their shapes are close to axisymmetric. We find no evidence that the
self-consistent distribution function of the nearly oblate inner halo is
comprised primarily of axisymmetric short-axis tube orbits. Orbits of all
families, and both types of particles are highly eccentric with mean
eccentricity >0.6. We find that randomly selected samples of halo stars show no
substructure in "integrals of motion" space. However individual accretion
events can be clearly identified in plots of metallicity versus formation time.
Dynamically young tidal debris is found primarily on a single type of orbit.
However, stars associated with older satellites become chaotically mixed during
the formation process (possibly due to scattering by the central bulge and
disk, and baryonic processes), and appear on all four types of orbits. We find
that the tidal debris in cosmological hydrodynamical simulations experiences
significantly more chaotic evolution than in collisionless simulations, making
it much harder to identify individual progenitors using phase space coordinates
alone. However by combining information on stellar ages and chemical abundances
with the orbital properties of halo stars in the underlying self-consistent
potential, the identification of progenitors is likely to be possible.


title: Presentation of the Motzkin Monoid

abstract:
  In 2010, Tom Halverson and Georgia Benkart introduced the Motzkin algebra, a
generalization of the Temperley-Lieb algebra, whose elements are diagrams that
can be multiplied by stacking one on top of the other. Halverson and Benkart
gave a diagrammatic algorithm for decomposing any Motzkin diagram into diagrams
of three subalgebras: the Right Planar Rook algebra, the Temperley-Lieb
algebra, and the Left Planar Rook algebra. We first explore the Right and Left
Planar Rook monoids, by finding presentations for these monoids by generators
and relations, using a counting argument to prove that our relations suffice.
We then turn to the newly-developed Motzkin monoid, where we describe
Halverson's decomposition algorithm algebraically, find a presentation by
generators and relations, and use a counting argument but with a much more
sophisticated algorithm.


title:
Homogeneously Saturated Model for Development in Time of the Price of an
  Asset

abstract:
  The time development of the price of a financial asset is considered by
constructing and solving Langevin equations for a homogeneously saturated
model, and for comparison, for a standard model and for a logistic model. The
homogeneously saturated model uses coupled rate equations for the money supply
and for the price of the asset, similar to the coupled rate equations for
population inversion and power density in a simple model of a homogeneously
broadened laser.
  Predictions of the models are compared for random numbers drawn from a
Student's t-distribution. It is known that daily returns of the DJIA and S&P
500 indices are fat tailed and are described well by Student's t-distributions
over the range of observed values. The homogeneously saturated model shows
returns that are consistent with daily returns for the indices (in the range of
-30% to +30%) whereas the standard model and the logistic model show returns
that are far from consistent with observed daily returns for the indices.


title: An improved sink particle algorithm for SPH simulations

abstract:
  Numerical simulations of star formation frequently rely on the implementation
of sink particles, (a) to avoid expending computational resource on the
detailed internal physics of individual collapsing protostars, (b) to derive
mass functions, binary statistics and clustering kinematics (and hence to make
comparisons with observation), and (c) to model radiative and mechanical
feedback; sink particles are also used in other contexts, for example to
represent accreting black holes in galactic nuclei. We present a new algorithm
for creating and evolving sink particles in SPH simulations, which appears to
represent a significant improvement over existing algorithms {\refrpt --
particularly in situations where sinks are introduced after the gas has become
optically thick to its own cooling radiation and started to heat up by
adiabatic compression}. (i) It avoids spurious creation of sinks. (ii) It
regulates the accretion of matter onto a sink so as to mitigate non-physical
perturbations in the vicinity of the sink. (iii) Sinks accrete matter, but the
associated angular momentum is transferred back to the surrounding medium. With
the new algorithm -- and modulo the need to invoke sufficient resolution to
capture the physics preceding sink formation -- the properties of sinks formed
in simulations are essentially independent of the user-defined parameters of
sink creation, or the number of SPH particles used.


title:
The ACS Nearby Galaxy Survey Treasury XI. The Remarkably Undisturbed NGC
  2403 Disk

abstract:
  We present detailed analysis of color-magnitude diagrams of NGC2403, obtained
from a deep (m<28) Hubble Space Telescope (HST) Wide Field Planetary Camera 2
observation of the outer disk of NGC2403, supplemented by several shallow
(m<26) HST Advanced Camera for Surveys fields. We derive the spatially resolved
star formation history of NGC2403 out to 11 disk scale lengths. In the inner
portions of the galaxy, we compare the recent star formation rates (SFRs) we
derive from the resolved stars with those measured using GALEX FUV + Spitzer
24-micron fluxes, finding excellent agreement between the methods. Our
measurements also show that the radial gradient in recent SFR mirror s the disk
exponential profile to 11 scale lengths with no break, extending to SFR
densities a factor of 100 lower than those that can be measured with GALEX and
Spitzer (2x10^{-6} M_{\sun} yr^{-1} kpc^{-2}). Furthermore, we find that the
cumulative stellar mass of the disk was formed at similar times at all radii.
We compare these characteristics of NGC2403 to those of its "morphological
twins," NGC300 and M33, showing that the structure and age distributions of the
NGC2403 disk are more similar to those of the relatively isolated system NGC300
than to those of the Local Group analog M33. We also discuss the environments
and HI morphologies of these three nearby galaxies, comparing them to
integrated light studies of larger samples of more distant galaxy disks. Taken
together, the physical properties and evolutionary history of NGC2403 suggest
that the galaxy has had no close encounters with other M81 group members and
may be falling into the group for the first time.


title:
3D mixing in hot Jupiter atmospheres. I. application to the day/night
  cold trap in HD 209458b

abstract:
  Hot Jupiters exhibit atmospheric temperatures ranging from hundreds to
thousands of Kelvin. Because of their large day-night temperature differences,
condensable species that are stable in the gas phase on the dayside, such as
TiO and silicates, may condense and gravitationally settle on the nightside.
Atmospheric circulation may counterbalance this tendency to gravitationally
settle. This three dimensional (3D) mixing of chemical species has not
previously been studied for hot Jupiters, yet it is crucial to assess the
existence and distribution of TiO and silicates in the atmospheres of these
planets. We perform 3D global circulation models of HD209458b including passive
tracers that advect with the 3D flow, including a source/sink on the nightside
to represent condensation and gravitational settling of haze particles. We show
that global advection patterns produce strong vertical mixing that can keep
condensable species lofted as long as they are trapped in particles of sizes of
a few microns or less on the night side. We show that vertical mixing results
not from small-scale convection but from the large-scale circulation driven by
the day-night heating contrast. Although this vertical mixing is not diffusive
in any rigorous sense, a comparison of our results with idealized diffusion
models allows a rough estimate of the vertical diffusion coefficient.
Kzz=5x10**4/Sqrt(Pbar) m2/s can be used in 1D models of HD 209458b. Moreover,
our models exhibit strong spatial and temporal variability in the tracer
concentration that could result in observable variations during transit or
secondary eclipse measurements. Finally, we apply our model to the case of TiO
in HD209458b and show that the day-night cold trap would deplete TiO if it
condenses into particles bigger than a few microns on the planet's night side,
making it unable to create the observed stratosphere of the planet.


title: On the Prompt Signals of Gamma Ray Bursts

abstract:
  We introduce a new model of gamma ray burst (GRB) that explains its observed
prompt signals, namely, its primary quasi-thermal spectrum and high energy
tail. This mechanism can be applied to either assumption of GRB progenitor:
coalescence of compact objects or hypernova explosion. The key ingredients of
our model are: (1) The initial stage of a GRB is in the form of a relativistic
quark-gluon plasma "lava"; (2) The expansion and cooling of this lava results
in a QCD phase transition that induces a sudden gravitational stoppage of the
condensed non-relativistic baryons and form a hadrosphere; (3) Acoustic shocks
and Alfven waves (magnetoquakes) that erupt in episodes from the epicenter
efficiently transport the thermal energy to the hadrospheric surface and induce
a rapid detachment of leptons and photons from the hadrons; (4) The detached
$e^+e^-$ and $\gamma$ form an opaque, relativistically hot leptosphere, which
expands and cools to $T \sim mc^2$, or 0.5 MeV, where $e^+e^- \to 2\gamma$ and
its reverse process becomes unbalanced, and the GRB photons are finally
released; (5) The "mode-conversion" of Alfven waves into electromagnetic waves
in the leptosphere provides a "snowplow" acceleration and deceleration that
gives rise to both the high energy spectrum of GRB and the erosion of its
thermal spectrum down to a quasi-thermal distribution. According to this model,
the observed GRB photons should have a redshifted peak frequency at $E_p \sim
\Gamma(1 + \beta/2)mc^2/(1 + z),$ where $\Gamma\sim {\cal{O}}(1)$ is the
Lorentz factor of the bulk flow of the lava, which may be determined from the
existing GRB data.


title:
Model Reduction of Descriptor Systems by Interpolatory Projection
  Methods

abstract:
  In this paper, we investigate interpolatory projection framework for model
reduction of descriptor systems. With a simple numerical example, we first
illustrate that employing subspace conditions from the standard state space
settings to descriptor systems generically leads to unbounded H2 or H-infinity
errors due to the mismatch of the polynomial parts of the full and
reduced-order transfer functions. We then develop modified interpolatory
subspace conditions based on the deflating subspaces that guarantee a bounded
error. For the special cases of index-1 and index-2 descriptor systems, we also
show how to avoid computing these deflating subspaces explicitly while still
enforcing interpolation. The question of how to choose interpolation points
optimally naturally arises as in the standard state space setting. We answer
this question in the framework of the H2-norm by extending the Iterative
Rational Krylov Algorithm (IRKA) to descriptor systems. Several numerical
examples are used to illustrate the theoretical discussion.


title: Distributions on symmetric cones II: Beta-Riesz distribution

abstract:
  This article derives several properties of the Riesz distributions, such as
their corresponding Bartlett decompositions, the inverse Riesz distributions
and the distribution of the generalised variance for real normed division
algebras. In addition, introduce a kind of generalised beta distribution termed
beta-Riesz distribution for real normed division algebras. Two versions of this
distributions are proposed and some properties are studied.


title: Variational theory of soliplasmon resonances

abstract:
  We present a first-principles derivation of the variational equations
describing the dynamics of the interaction of a spatial soliton and a surface
plasmon polariton (SPP) propagating along a metal/dielectric interface. The
variational ansatz is based on the existence of solutions exhibiting
differentiated and spatially resolvable localized soliton and SPP components.
These states, referred to as soliplasmons, can be physically understood as
bound states of a soliton and a SPP. Their respective dispersion relations
permit the existence of a resonant interaction between them, as pointed out in
Ref.[1]. The existence of soliplasmon states and their interesting nonlinear
resonant behavior has been validated already by full-vector simulations of the
nonlinear Maxwell's equations, as reported in Ref.[2]. Here, we provide the
theoretical demonstration of the nonlinear resonator model previously
introduced in our previous work and analyze all the approximations needed to
obtain it. We also provide some extensions of the model to improve its
applicability.


title:
Comparative Study of Chemically Synthesized and Exfoliated Multilayer
  MoS2 Field-Effect Transistors

abstract:
  We report the realization of field-effect transistors (FETs) made with
chemically synthesized multilayer 2D crystal semiconductor MoS2. Electrical
properties such as the FET mobility, subthreshold swing, on/off ratio, and
contact resistance of chemically synthesized (s-) MoS2 are indistinguishable
from that of mechanically exfoliated (x-) MoS2, however flat-band voltages are
different, possibly due to polar chemical residues originating in the transfer
process. Electron diffraction studies and Raman spectroscopy show the
structural similarity of s-MoS2 to x-MoS2. This initial report on the behavior
and properties of s-MoS2 illustrates the feasibility of electronic devices
using synthetic layered 2D crystal semiconductors.


title: Gradient estimates for SDEs Driven by Multiplicative L\'evy Noise

abstract:
  Gradient estimates are derived, for the first time, for the semigroup
associated to a class of stochastic differential equations driven by
multiplicative L\'evy noise. In particular, the estimates are sharp for
$\alpha$-stable type noises. To derive these estimates, a new derivative
formula of Bismut-Elworthy-Li's type is established for the semigroup by using
the Malliavin calculus and a finite-jump approximation argument.


title: Average-Case Performance of Rollout Algorithms for Knapsack Problems

abstract:
  Rollout algorithms have demonstrated excellent performance on a variety of
dynamic and discrete optimization problems. Interpreted as an approximate
dynamic programming algorithm, a rollout algorithm estimates the value-to-go at
each decision stage by simulating future events while following a greedy
policy, referred to as the base policy. While in many cases rollout algorithms
are guaranteed to perform as well as their base policies, there have been few
theoretical results showing additional improvement in performance. In this
paper we perform a probabilistic analysis of the subset sum problem and
knapsack problem, giving theoretical evidence that rollout algorithms perform
strictly better than their base policies. Using a stochastic model from the
existing literature, we analyze two rollout methods that we refer to as the
consecutive rollout and exhaustive rollout, both of which employ a simple
greedy base policy. For the subset sum problem, we prove that after only a
single iteration of the rollout algorithm, both methods yield at least a 30%
reduction in the expected gap between the solution value and capacity, relative
to the base policy. Analogous results are shown for the knapsack problem.


title:
Conditional Results for a Class of Arithmetic Functions: a variant of H.
  L. Montgomery and R. C. Vaughan's method

abstract:
  Let $a, b,c $ and $k$ be positive integers such that $1\leq a\leq
b,a<c<2(a+b), c\ne b$ and $(a,b,c)=1$. Define the arithmetic function
$f_k(a,b;c;n)$ by $$ \sum_{n=1}^{\infty}\frac{f_k(a,b;c;n)}{n^s}=\frac{\zeta
(as)\zeta (bs)}{\zeta^k(cs)}, \Re s >1.$$
  Let $\Delta_k(a,b;c;x)$ denote the error term of the summatory function of
the function $f_k(a,b;c;n).$ IN this paper we shall give two expressions of
$\Delta_k(a,b;c;x)$. As applications, we study the so-called $(l,r)$-integers,
the generalized square-full integers, the $e-r$-free integers, the divisor
problem over $r$-free integers, the $e$-square-free integers.
  An important tool is a generalization of a method of H. L. Montgomery and R.
C. Vaughan.


title: Reconstruct Lame parameters of linear isotropic elasticity system

abstract:
  Transient Elastography enables detection and characterization of tissue
abnormalities. In this paper we assume that the displacements are modeled by
linear isotropic elasticity system and the tissue displacement has been
obtained by the first step in hybrid methods. Then we reconstruct the Lam\'e
parameters of this system from knowledge of tissue displacement. We show that
for a sufficiently large number of solutions of the elasticity system and for
an open set of the well-chosen boundary conditions, $(\lambda,\mu)$ can be
uniquely and stably reconstructed. The set of well-chosen boundary conditions
is characterized in terms of appropriate complex geometrical optics solutions.


title: Mass function and particle creation in Schwarzschild-de Sitter spacetime

abstract:
  We construct a mass or energy function for the non-Nariai class
Schwarzschild-de Sitter black hole spacetime in the region between the black
hole and the cosmological event horizons. The mass function is local, positive
definite, continuous and increases monotonically with the radial distance from
the black hole event horizon. We derive the Smarr formula using this mass
function, and demonstrate that the mass function reproduces the two-temperature
Schwarzschild-de Sitter black hole thermodynamics, along with a term
corresponding to the negative pressure due to positive cosmological constant.
We further give a field theoretic derivation of the particle creation by both
the horizons and discuss its connection with the mass function.


title:
Modeling a nanocantilever based biosensor using a stochastically
  perturbed harmonic oscillator

abstract:
  Nanoscale biosensors are devices designed to detect analytes by combining
biological components and physicochemical detectors. One of the well known
methods of constructing these sensors is by using nanocantilevers. These
microscopic 'diving boards' are coated with binding probes that have an
affinity to a particular amino acid, enzyme or protein in living organisms.
When these probes attract some target particles, such as biomolecules, they
change the vibrating frequency of the cantilever. This process is random in
nature and produces fluctuations in the frequency and damping of the
cantilever. In this paper, we studied the effect of these fluctuations using a
stochastically perturbed classical harmonic oscillator.


title:
Determination of approximate nonlinear self-adjointenss and approximate
  conservation law

abstract:
  Approximate nonlinear self-adjointness is an effective method to construct
approximate conservation law of perturbed partial differential equations
(PDEs). In this paper, we study the relations between approximate nonlinear
self-adjointness of perturbed PDEs and nonlinear self-adjointness of the
corresponding unperturbed PDEs, and consequently provide a simple approach to
discriminate approximate nonlinear self-adjointness of perturbed PDEs.
Moreover, a succinct approximate conservation law formula by virtue of the
known conservation law of the unperturbed PDEs is given in an explicit form. As
an application, we classify a class of perturbed wave equations to be
approximate nonlinear self-adjointness and construct the general approximate
conservation laws formulae. The specific examples demonstrate that approximate
nonlinear self-adjointness can generate new approximate conservation laws.


title:
Applications and a Three-dimensional Desktop Environment for an
  Immersive Virtual Reality System

abstract:
  We developed an application launcher called Multiverse for scientific
visualizations in a CAVE-type virtual reality (VR) system. Multiverse can be
regarded as a type of three-dimensional (3D) desktop environment. In
Multiverse, a user in a CAVE room can browse multiple visualization
applications with 3D icons and explore movies that float in the air. Touching
one of the movies causes "teleportation" into the application's VR space. After
analyzing the simulation data using the application, the user can jump back
into Multiverse's VR desktop environment in the CAVE.


title:
Measurement of the differential cross sections for isolated direct
  photon pair production in $p \bar p$ collisions at $\sqrt{s} = 1.96$ TeV

abstract:
  We present measurements of direct photon pair production cross sections using
8.5 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron
$p \bar p$ collider. The results are presented as differential distributions of
the photon pair invariant mass $d\sigma/dM_{\gamma \gamma}$, pair transverse
momentum $d \sigma /dp^{\gamma \gamma}_T$, azimuthal angle between the photons
$d\sigma/d\Delta \phi_{\gamma \gamma}$, and polar scattering angle in the
Collins-Soper frame $d\sigma /d|\cos \theta^*|$. Measurements are performed for
isolated photons with transverse momenta $p^{\gamma}_T>18 ~(17)$ GeV for the
leading (next-to-leading) photon in $p_T$, pseudorapidities
$|\eta^{\gamma}|<0.9$, and a separation in $\eta-\phi$ space $\Delta\mathcal
R_{\gamma\gamma} > 0.4$. We present comparisons with the predictions from Monte
Carlo event generators {\sc diphox} and {\sc resbos} implementing QCD
calculations at next-to-leading order, $2\gamma${\sc nnlo} at
next-to-next-to-leading order, and {\sc sherpa} using matrix elements with
higher-order real emissions matched to parton shower.