title: Bijections for the Shi and Ish arrangements

abstract:
  The {\sf Shi hyperplane arrangement} Shi(n) was introduced by Shi to study
the Kazhdan-Lusztig cellular structure of the affine symmetric group. The {\sf
Ish hyperplane arrangement} Ish(n) was introduced by Armstrong in the study of
diagonal harmonics. Armstrong and Rhoades discovered a deep combinatorial
similarity between the Shi and Ish arrangements. We solve a collection of
problems posed by Armstrong and Armstrong-Rhoades by giving bijections between
regions of Shi(n) and Ish(n) which preserve certain statistics. Our bijections
generalize to the `deleted arrangements' Shi(G) and Ish(G) which depend on a
subgraph G of the complete graph K_n on n vertices. The key tools in our
bijections are the introduction of an Ish analog of parking functions called
{\sf rook words} and a new instance of the cycle lemma of enumerative
combinatorics.


title:
Energy transfer and dissipation in equilibrium and nonequilibrium
  turbulence

abstract:
  The nonequilibrium dissipation behaviour discovered for decaying fractal
square grid-generated turbulence is experimentally investigated using hot-wire
anemometry in a wind tunnel. The previous results are consolidated and
benchmarked with turbulence generated by regular square-mesh grids, designed to
retain certain geometrical parameters of the fractal square grid. This
comparison shows that the nonequilibrium behaviour is manifested in both
fractal square grid- and regular square-mesh grid-generated turbulence for a
downstream region during the turbulence decay up to the first few multiples of
the wake interaction distance. For one of the regular grids it is shown that
beyond this region there is a transition to the classical dissipation behaviour
if the local turbulent Reynolds number is sufficiently high. A sharp conclusion
can thus be drawn that this behaviour is more general than initially thought
and therefore of much greater scientific and engineering significance. The
nonequilibrium dissipation phenomena is further investigated by experimentally
measuring the terms of an inhomogeneous von Karman-Howarth-Monin equation. This
equation is essentially a scale-by-scale energy transfer budget. From the data
it is shown that the inhomogeneity of the turbulent flow does not tamper with
the nonequilibrium phenomena and that the scaling of the nonlinear energy
transfer, i.e. the transfer of energy to the small-scales, is out of balance
with the dissipation. This imbalance leads to the growth of the small-scale
advection to compensate for the increasing gap between the energy transferred
and the energy dissipated. For the highest Reynolds number data it is also
shown that the nonequilibrium dissipation scaling appears to be consistent with
the expectation that it is asymptotically independent of the viscosity with a
power-law spectra with the Kolmogorov-Obukhov exponent -5/3.


title: Why there is no noon-midnight red shift in the GPS

abstract:
  Although the effects of solar (and lunar) gravitational potentials on the
frequencies of orbiting Global Positioning System (GPS) clocks are actually no
more than a few parts in 10^(15), a na\"ive calculation appears to show that
such effects are much larger, and depend on whether the orbiting clock is
between the earth and the sun, or on the side of the earth opposite to the sun.
Consequently questions about whether such effects have been properly accounted
for in the GPS continue to arise. This issue has been discussed in a misleading
way in terms of cancellations arising from a second-order Doppler shift in the
literature for almost 50 years. The purpose of this article is to provide a
correct argument, based on fundamental relativity principles, so that one may
understand in a simple way why the effects of external solar system bodies on
orbiting or earth-bound clocks in the GPS are so small. The relativity of
simultaneity plays a crucial role in these arguments.


title:
Charge expulsion, charge inhomogeneity and phase separation in dynamic
  Hubbard models

abstract:
  Dynamic Hubbard models are extensions of the conventional Hubbard model that
take into account the fact that atomic orbitals expand upon double occupancy.
It is shown here that systems described by dynamic Hubbard models have a
tendency to expel negative charge from their interior to the surface, and to
develop charge inhomogeneity and even phase separation in the bulk. These
effects are associated with lowering of electronic kinetic energy. We propose
that these models may explain the charge inhomogeneity and negatively charged
grain boundaries observed in cuprate oxides and other materials.


title:
Alpha invariants and K-stability for general polarisations of Fano
  varieties

abstract:
  We provide a sufficient condition for polarisations of Fano varieties to be
K-stable in terms of Tian's alpha invariant, which uses the log canonical
threshold to measure singularities of divisors in the linear system associated
to the polarisation. This generalises a result of Odaka-Sano in the
anti-canonically polarised case, which is the algebraic counterpart of Tian's
analytic criterion implying the existence of a K\"{a}hler-Einstein metric. As
an application, we give new K-stable polarisations of a general degree one del
Pezzo surface. We also prove a corresponding result for log K-stability.


title:
Incentives, Quality, and Risks: A Look Into the NSF Proposal Review
  Pilot

abstract:
  The National Science Foundation (NSF) will be experimenting with a new
distributed approach to reviewing proposals, whereby a group of principal
investigators (PIs) or proposers in a subfield act as reviewers for the
proposals submitted by the same set of PIs. To encourage honesty, PIs' chances
for getting funded are tied to the quality of their reviews (with respect to
the reviews provided by the entire group), in addition to the quality of their
proposals. Intuitively, this approach can more fairly distribute the review
workload, discourage frivolous proposal submission, and encourage high quality
reviews. On the other hand, this method has already raised concerns about the
integrity of the process and the possibility of strategic manipulation. In this
paper, we take a closer look at three specific issues in an attempt to gain a
better understanding of the strengths and limitations of the new process beyond
first impressions and anecdotal evidence. We start by considering the benefits
and drawbacks of bundling the quality of PIs' reviews with the scientific merit
of their proposals. We then consider the issue of collusion and favoritism.
Finally, we examine whether the new process puts controversial proposals at a
disadvantage. We conclude that some benefits of using review quality as an
incentive mechanism may outweigh its drawbacks. On the other hand, even a
coalition of two PIs can cause significant harm to the process, as the built-in
incentives are not strong enough to deter collusion. While we also confirm the
common suspicion that the process is skewed toward non-controversial proposals,
the more unexpected finding is that among equally controversial proposals,
those of lower quality get a leg up through this process. Thus the process not
only favors non-controversial proposals, but in some sense, mediocrity. We also
discuss possible ways to improve this review process.


title: Preheating in a DBI Inflation Model

abstract:
  We study the preheating process in a model of DBI inflation with a DBI-type
inflaton coupling to a canonical entropy field. At the end of inflation, the
inflaton field oscillates around its vacuum which can arise from an infrared
cutoff parameter on the warp factor and correspondingly the evolution of its
fluctuations can be approximately described by a generalized Hill's equation in
third order. We study the field fluctuations numerically and show that they
could grow exponentially since the instability bands commonly exist in the DBI
models if the amplitudes of background oscillations are of order or larger than
the cutoff parameter. Our numerical result also reveals that the particle
excitation of the matter field is more dramatic than that in usual case since
the parametric resonance lasts longer when the effect of a warp factor is taken
into account. Therefore, we conclude that the preheating process in the model
of DBI inflation could be more efficient than that in standard inflation
models.


title: Probabilistic Fr\'echet Means for Time Varying Persistence Diagrams

abstract:
  In order to use persistence diagrams as a true statistical tool, it would be
very useful to have a good notion of mean and variance for a set of diagrams.
In 2011, Mileyko and his collaborators made the first study of the properties
of the Fr\'echet mean in $(\mathcal{D}_p,W_p)$, the space of persistence
diagrams equipped with the p-th Wasserstein metric. In particular, they showed
that the Fr\'echet mean of a finite set of diagrams always exists, but is not
necessarily unique. The means of a continuously-varying set of diagrams do not
themselves (necessarily) vary continuously, which presents obvious problems
when trying to extend the Fr\'echet mean definition to the realm of vineyards.
  We fix this problem by altering the original definition of Fr\'echet mean so
that it now becomes a probability measure on the set of persistence diagrams;
in a nutshell, the mean of a set of diagrams will be a weighted sum of atomic
measures, where each atom is itself a persistence diagram determined using a
perturbation of the input diagrams. This definition gives for each $N$ a map
$(\mathcal{D}_p)^N \to \mathbb{P}(\mathcal{D}_p)$. We show that this map is
H\"older continuous on finite diagrams and thus can be used to build a useful
statistic on time-varying persistence diagrams, better known as vineyards.


title: Fundamental domains in the Einstein Universe

abstract:
  We will discuss fundamental domains for actions of discrete groups on the
3-dimensional Einstein Universe. These will be bounded by crooked surfaces,
which are conformal compactifications of surfaces that arise in the
construction of Margulis spacetimes. We will show that there exist pairwise
disjoint crooked surfaces in the 3-dimensional Einstein Universe. As an
application, we can construct explicit examples of groups acting properly on an
open subset of that space.


title:
Discovery of WASP-65b and WASP-75b: Two Hot Jupiters Without Highly
  Inflated Radii

abstract:
  We report the discovery of two transiting hot Jupiters, WASP-65b (M_pl = 1.55
+/- 0.16 M_J; R_pl = 1.11 +/- 0.06 R_J), and WASP-75b (M_pl = 1.07 +/- 0.05
M_J; R_pl = 1.27 +/- 0.05 R_J). They orbit their host star every 2.311, and
2.484 days, respectively. The planet host WASP-65 is a G6 star (T_eff = 5600 K,
[Fe/H] = -0.07 +/- 0.07, age > 8 Gyr); WASP-75 is an F9 star (T_eff = 6100 K,
[Fe/H] = 0.07 +/- 0.09, age of 3 Gyr). WASP-65b is one of the densest known
exoplanets in the mass range 0.1 and 2.0 M_J (rho_pl = 1.13 +/- 0.08 rho_J), a
mass range where a large fraction of planets are found to be inflated with
respect to theoretical planet models. WASP-65b is one of only a handful of
planets with masses of around 1.5 M_J, a mass regime surprisingly
underrepresented among the currently known hot Jupiters. The radius of
Jupiter-mass WASP-75b is slightly inflated (< 10%) as compared to theoretical
planet models with no core, and has a density similar to that of Saturn (rho_pl
= 0.52 +/- 0.06 rho_J).


title:
Universal commutator relations, Bogomolov multipliers, and commuting
  probability

abstract:
  Let $G$ be a finite $p$-group. We prove that whenever the commuting
probability of $G$ is greater than $(2p^2 + p - 2)/p^5$, the unramified Brauer
group of the field of $G$-invariant functions is trivial. Equivalently, all
relations between commutators in $G$ are consequences of some universal ones.
The bound is best possible, and gives a global lower bound of $1/4$ for all
finite groups. The result is attained by describing the structure of groups
whose Bogomolov multipliers are nontrivial, and Bogomolov multipliers of all of
their proper subgroups and quotients are trivial. Applications include a
classification of $p$-groups of minimal order that have nontrivial Bogomolov
multipliers and are of nilpotency class $2$, a nonprobabilistic criterion for
the vanishing of the Bogomolov multiplier, and establishing a sequence of
Bogomolov's absolute $\gamma$-minimal factors which are $2$-groups of
arbitrarily large nilpotency class, thus providing counterexamples to some of
Bogomolov's claims. In relation to this, we fill a gap in the proof of
triviality of Bogomolov multipliers of finite simple groups.


title: The Conformal Stealth of any Standard Cosmology

abstract:
  It is shown that any homogeneous and isotropic universe, independently of its
spatial topology and matter content, allows for the presence of a conformal
stealth, i.e. a nontrivial conformally invariant scalar field with vanishing
energy-momentum tensor, which evolves along with the universe without causing
even the smallest backreaction. Surprisingly, this gravitationally invisible
universal witness is inhomogeneous with zero consequences for the underlying
cosmology. Additionally, it is shown that these results are not exclusive of a
four-dimensional universe by generalizing them to higher dimensions.


title: Computing conformal maps onto circular domains

abstract:
  We show that, given a non-degenerate, finitely connected domain $D$, its
boundary, and the number of its boundary components, it is possible to compute
a conformal mapping of $D$ onto a circular domain \emph{without} prior
knowledge of the circular domain. We do so by computing a suitable bound on the
error in the Koebe construction (but, again, without knowing the circular
domain in advance). As a scientifically sound model of computation with
continuous data, we use Type-Two Effectivity.


title: Viscous dark matter growth in (neo-)Newtonian cosmology

abstract:
  We assume cold dark matter to possess a small bulk-viscous pressure which
typically attenuates the growth of inhomogeneities. Explicit calculations,
based on Eckart's theory of dissipative processes, reveal that for viscous cold
dark matter the usual Newtonian approximation for perturbation scales smaller
than the Hubble scale is no longer valid. We advocate the use of a
neo-Newtonian approach which consistently incorporates pressure effects into
the fluid dynamics and correctly reproduces the general relativistic dynamics.
This result is of interest for numerical simulations of nonlinear structure
formation involving nonstandard dark-matter fluids. We obtain upper limits on
the magnitude of the viscous pressure by requiring that relevant perturbation
amplitudes should grow sufficiently to enter the nonlinear stage.


title: The TeV Cosmic-Ray Anisotropy from Local Dark Matter Annihilation

abstract:
  Several experiments have reported regions in the TeV sky with an excess of
cosmic rays. Here we consider the possibility that the excess cosmic rays are
coming from dark matter annihilation in nearby subhalos. We provide motivation
for dark matter as the source of the excess and show that dark matter
annihilations can naturally produce the cosmic ray anisotropy without the need
for exotic dark matter models. We show that viable dark matter explanations of
the cosmic ray excess are consistent with current measurements of antiprotons,
positrons, and gamma-rays. Additionally, we show that the dark matter
interpretation of the observed anisotropy predicts detections in several cosmic
ray channels by the next generation of experiments.


title: Period Finding with Adiabatic Quantum Computation

abstract:
  We outline an efficient quantum-adiabatic algorithm that solves Simon's
problem, in which one has to determine the `period', or xor-mask, of a given
black-box function. We show that the proposed algorithm is exponentially faster
than its classical counterpart and has the same complexity as the corresponding
circuit-based algorithm. Together with other related studies, this result
supports a conjecture that the complexity of adiabatic quantum computation is
equivalent to the circuit-based computational model in a stronger sense than
the well-known, proven polynomial equivalence between the two paradigms. We
also discuss the importance of the algorithm and its theoretical and
experimental implications for the existence of an adiabatic version of Shor's
integer factorization algorithm that would have the same complexity as the
original algorithm.


title: Quantifying playmaking ability in hockey

abstract:
  It is often said that a sign of a great player is that he makes the players
around him better. The player may or may not score much himself, but his
teammates perform better when he plays. One way a hockey player can improve his
or her teammates' performance is to create goal scoring opportunities.
Unfortunately, in hockey goal scoring is relatively infrequent, and statistics
like assists can be unreliable as a measure of a player's playmaking ability.
Assists also depend on playing time, power play usage, the strength of a
player's linemates, and other factors. In this paper we develop a metric for
quantifying playmaking ability that addresses these issues. Our playmaking
metric has two benefits over assists for which we can provide statistical
evidence: it is more consistent than assists, and it is better than assists at
predicting future assists. Quantifying player contributions using this measure
can assist decision-makers in identifying, acquiring, and integrating
successful playmakers into their lineups.


title: Infinite-body optimal transport with Coulomb Cost

abstract:
  We introduce and analyze symmetric infinite-body optimal transport (OT)
problems with cost function of pair potential form. We show that for a natural
class of such costs, the optimizer is given by the independent product measure
all of whose factors are given by the one-body marginal. This is in striking
contrast to standard finite-body OT problems, in which the optimizers are
typically highly correlated, as well as to infinite-body OT problems with
Gangbo-Swiech cost. Moreover, by adapting a construction from the study of
exchangeable processes in probability theory, we prove that the corresponding
$N$-body OT problem is well approximated by the infinite-body problem.
  To our class belongs the Coulomb cost which arises in many-electron quantum
mechanics. The optimal cost of the Coulombic N-body OT problem as a function of
the one-body marginal density is known in the physics and quantum chemistry
literature under the name SCE functional, and arises naturally as the
semiclassical limit of the celebrated Hohenberg-Kohn functional. Our results
imply that in the inhomogeneous high-density limit (i.e. $N\to\infty$ with
arbitrary fixed inhomogeneity profile $\rho/N$), the SCE functional converges
to the mean field functional.
  We also present reformulations of the infinite-body and N-body OT problems as
two-body OT problems with representability constraints and give a dual
characterization of representable two-body measures which parallels an
analogous result by Kummer on quantum representability of two-body density
matrices.


title: The strategic form of quantum prisoners' dilemma

abstract:
  In its normal form prisoners' dilemma (PD) is represented by a payoff matrix
showing players strategies and payoffs. To obtain distinguishing trait and
strategic form of PD certain constraints are imposed on the elements of its
payoff matrix. We quantize PD by generalized quantization scheme to analyze its
strategic behavior in quantum domain. The game starts with general entangled
state of the form $\left}\psi\right\rangle =\cos\frac{\xi}%
{2}\left|00\right\rangle +i\sin\frac{\xi}{2}\left|11\right\rangle $ and the
measurement for payoffs is performed in entangled and product bases. We show
that for both measurements there exist respective cutoff values of entanglement
of initial quantum state up to which strategic form of game remains intact.
Beyond these cutoffs the quantized PD behaves like chicken game up to another
cutoff value. For the measurement in entangled basis the dilemma is resolved
for\ $\sin\xi>\frac{1}{7}$ with $Q\otimes Q$ as a NE but the quantized game
behaves like PD when $\sin\xi>\frac{1}{3}$; whereas in the range
$\frac{1}{7}<\sin\xi<\frac{1}{3}$ it behaves like chicken game (CG)\ with
$Q\otimes Q$ as a NE. For the measurement in product basis the quantized PD
behaves like classical PD for $\sin^{2}\frac{\xi}{2}<\frac{1}{3}$ with
$D\otimes D$ as a NE. In region $\frac{1}{3}<\sin^{2}\frac{\xi}{2}%
<\frac{3}{7}$ the quantized PD behaves like classical CG with $C\otimes D$ and
$D\otimes C$ as NE.


title:
Selection Mammogram Texture Descriptors Based on Statistics Properties
  Backpropagation Structure

abstract:
  Computer Aided Diagnosis (CAD) system has been developed for the early
detection of breast cancer, one of the most deadly cancer for women. The benign
of mammogram has different texture from malignant. There are fifty mammogram
images used in this work which are divided for training and testing. Therefore,
the selection of the right texture to determine the level of accuracy of CAD
system is important. The first and second order statistics are the texture
feature extraction methods which can be used on a mammogram. This work
classifies texture descriptor into nine groups where the extraction of features
is classified using backpropagation learning with two types of multi-layer
perceptron (MLP). The best texture descriptor as selected when the value of
regression 1 appears in both the MLP-1 and the MLP-2 with the number of epoches
less than 1000. The results of testing show that the best selected texture
descriptor is the second order (combination) using all direction (0, 45, 90 and
135) that have twenty four descriptors.


title: Exact blocking formulas for spin and gauge models

abstract:
  Using the example of the two-dimensional (2D) Ising model, we show that in
contrast to what can be done in configuration space, the tensor renormalization
group (TRG) formulation allows one to write exact, compact, and manifestly
local blocking formulas and exact coarse grained expressions for the partition
function. We argue that similar results should hold for most models studied by
lattice gauge theorists. We provide exact blocking formulas for several 2D spin
models (the O(2) and O(3) sigma models and the SU(2) principal chiral model)
and for the 3D gauge theories with groups Z_2, U(1) and SU(2). We briefly
discuss generalizations to other groups, higher dimensions and practical
implementations.


title:
Veni Vidi Vici, A Three-Phase Scenario For Parameter Space Analysis in
  Image Analysis and Visualization

abstract:
  Automatic analysis of the enormous sets of images is a critical task in life
sciences. This faces many challenges such as: algorithms are highly
parameterized, significant human input is intertwined, and lacking a standard
meta-visualization approach. This paper proposes an alternative iterative
approach for optimizing input parameters, saving time by minimizing the user
involvement, and allowing for understanding the workflow of algorithms and
discovering new ones. The main focus is on developing an interactive
visualization technique that enables users to analyze the relationships between
sampled input parameters and corresponding output. This technique is
implemented as a prototype called Veni Vidi Vici, or "I came, I saw, I
conquered." This strategy is inspired by the mathematical formulas of numbering
computable functions and is developed atop ImageJ, a scientific image
processing program. A case study is presented to investigate the proposed
framework. Finally, the paper explores some potential future issues in the
application of the proposed approach in parameter space analysis in
visualization.


title: Geometrical CP violation with a complete fermion sector

abstract:
  We consider Delta(27) models featuring geometrical CP violation, and analyse
several structures that can obtain the observed lepton masses and mixing. The
leptonic structures considered are entirely consistent with structures that
reproduce the experimental data in the quark sector. This constitutes an
existence proof of geometrical CP violation models accounting for the masses
and mixing of all fermions.


title:
New higher-derivative invariants in N=2 supergravity and the
  Gauss-Bonnet term

abstract:
  A new class of N=2 locally supersymmetric higher-derivative invariants is
constructed based on logarithms of conformal primary chiral superfields. They
characteristically involve a coupling to R_{\mu\nu}^2 - 1/3*R^2, which equals
the non-conformal part of the Gauss-Bonnet term. Upon combining one such
invariant with the known supersymmetric version of the square of the Weyl
tensor, one obtains the supersymmetric extension of the Gauss-Bonnet term. The
construction is carried out in the context of both conformal superspace and the
superconformal multiplet calculus. The new class of supersymmetric invariants
resolves two open questions. The first concerns the proper identification of
the 4D supersymmetric invariants that arise from dimensional reduction of the
5D mixed gauge-gravitational Chern-Simons term. The second is why the pure
Gauss-Bonnet term without supersymmetric completion has reproduced the correct
result in calculations of the BPS black hole entropy in certain models.


title: A spectral sequence for Iwasawa adjoints

abstract:
  We establish a purely algebraic tool for studying the Iwasawa adjoints of
some natural Iwasawa modules for $p$-adic Lie group extensions of number
fields, by relating them to certain continuous Galois cohomology groups via a
spectral sequence.


title:
Time-Domain Large Signal Investigation on Dynamic Responses of the GDCC
  Quarterly Wavelength Shifted Distributed Feedback Semiconductor Laser

abstract:
  A numerical investigation on the dynamic large-signal analysis using a
time-domain traveling wave model of quarter wave-shifted distributed feedback
semiconductor lasers diode with a Gaussian distribution of the coupling
coefficient (GDCC) is presented. It is found that the single-mode behavior and
the more hole-burning effect corrections of quarter wave-shifted distributed
feedback laser with large coupling coefficient can be improved significantly by
this new proposed light source.


title: Making Laplacians commute

abstract:
  In this paper, we construct multimodal spectral geometry by finding a pair of
closest commuting operators (CCO) to a given pair of Laplacians. The CCOs are
jointly diagonalizable and hence have the same eigenbasis. Our construction
naturally extends classical data analysis tools based on spectral geometry,
such as diffusion maps and spectral clustering. We provide several synthetic
and real examples of applications in dimensionality reduction, shape analysis,
and clustering, demonstrating that our method better captures the inherent
structure of multi-modal data.


title: Photonic density of states enhancement in finite graphene multilayers

abstract:
  We consider the optical properties of finite systems composed of a series of
graphene sheets separated by thin dielectric layers. Because these systems
respond as conductors to electric fields in the plane of the graphene sheets
and as insulators to perpendicular electric fields, they can be expected to
have properties similar to those of hyperbolic metamaterials. We show that
under typical experimental conditions graphene/dielectric multilayers have
enhanced Purcell factors, and enhanced photonic densities-of-states in both the
THz and mid-IR frequency range. These behaviors can be traced to the coupled
plasmon modes of the multi-layer graphene system. We show that these results
can be obtained with just a few layers of graphene.


title:
Uniqueness of extremizers for an endpoint inequality of the $k$-plane
  transform

abstract:
  The $k$-plane transform is a bounded operator from $\lp$ to $L^q$ of the
Grassmann manifold of all affine $k$-planes in $\R^n$ for certain exponents
depending on $k$ and $n$. In the endpoint case $q=n+1$, we identify all
extremizers of the associated inequality for the general $k$-plane transform.


title: An exciton-polariton mediated all-optical router

abstract:
  We propose an all-optical nonlinear router based on a double barrier gate
connected to periodically modulated guides. A semiconductor microcavity is
driven nonresonantly in-between the barriers to form an exciton-polariton
condensate on a discrete state that is subject to the exciton blueshift. The
subsequent coherent optical signal is allowed to propagate through a guide
provided that the condensate energy is resonant with a miniband or is blocked
if it faces a gap. While a symmetric sample operates as an optical switch, its
asymmetric counterpart embodies a router turned to be polarization selective
under applied magnetic field.


title:
The dependence of Galactic outflows on the properties and orientation of
  zCOSMOS galaxies at z ~ 1

abstract:
  We present an analysis of cool outflowing gas around galaxies, traced by MgII
absorption lines in the co-added spectra of a sample of 486 zCOSMOS galaxies at
1 < z < 1.5. These galaxies span a range of stellar masses (9.45<
log[M*/Msun]<10.7) and star formation rates (0.14 < log [SFR/Msun/yr] < 2.35).
We identify the cool outflowing component in the MgII absorption and find that
the equivalent width of the outflowing component increases with stellar mass.
The outflow equivalent width also increases steadily with the increasing star
formation rate of the galaxies. At similar stellar masses the blue galaxies
exhibit a significantly higher outflow equivalent width as compared to red
galaxies. The outflow equivalent width shows strong effect with star formation
surface density ({\Sigma}SFR) of the sample. For the disk galaxies, the outflow
equivalent width is higher for the face-on systems as compared to the edge-on
ones, indicating that for the disk galaxies, the outflowing gas is primarily
bipolar in geometry. Galaxies typically exhibit outflow velocities ranging from
-200 km/s to -300 km/s and on average the face-on galaxies exhibit higher
outflow velocity as compared to the edge-on ones. Galaxies with irregular
morphologies exhibit outflow equivalent width as well as outflow velocities
comparable to face on disk galaxies. These galaxies exhibit minimum mass
outflow rates > 5-7 Msun/yr and a mass loading factor ({\eta} = dMout/dt /SFR)
comparable to the star formation rates of the galaxies.


title:
New Electron Beam-Dump Experiments to Search for MeV to few-GeV Dark
  Matter

abstract:
  In a broad class of consistent models, MeV to few-GeV dark matter interacts
with ordinary matter through weakly coupled GeV-scale mediators. We show that a
suitable meter-scale (or smaller) detector situated downstream of an electron
beam-dump can sensitively probe dark matter interacting via sub-GeV mediators,
while B-factory searches cover the 1-5 GeV range. Combined, such experiments
explore a well-motivated and otherwise inaccessible region of dark matter
parameter space with sensitivity several orders of magnitude beyond existing
direct detection constraints. These experiments would also probe invisibly
decaying new gauge bosons ("dark photons") down to kinetic mixing of \epsilon ~
10^{-4}, including the range of parameters relevant for explaining the
(g-2)_{\mu} discrepancy. Sensitivity to other long-lived dark sector states and
to new milli-charge particles would also be improved.


title: The Circular Velocity Function of Group Galaxies

abstract:
  A robust prediction of $\Lambda{\rm CDM}$ cosmology is the halo circular
velocity function (CVF), a dynamical cousin of the halo mass function. The
correspondence between theoretical and observed CVFs is uncertain, however:
cluster galaxies are reported to exhibit a power-law CVF consistent with
$N$-body simulations, but that of the field is distinctly Schechter-like,
flattened relative to $\Lambda{\rm CDM}$ expectations at circular velocities
$v_c \lesssim 200\, {\rm km\, s^{-1}}$. Groups offer a powerful probe of the
role environment plays in this discrepancy as they bridge the field and
clusters. Here, we construct the CVF for a large, mass- and
multiplicity-complete sample of group galaxies from the Sloan Digital Sky
Survey. Using independent photometric $v_c$ estimators, we find no transition
from a field- to $\Lambda{\rm CDM}$-shaped CVF above $v_c = 50\, {\rm km\,
s^{-1}}$ as a function of group halo mass. All groups with $12.4 \lesssim \log
M_{\rm halo} / M_{\odot} \lesssim 15.1$ (Local Group analogs to rich clusters)
display similar Schechter-like CVFs marginally suppressed at low-$v_c$ compared
to that of the field. Conversely, some agreement with $N$-body results emerges
for samples saturated with late-type galaxies, with isolated late-types
displaying a CVF similar in shape to $\Lambda{\rm CDM}$ predictions. We
conclude that the flattening of the low-$v_c$ slope in groups is due to their
depressed late-type fractions -- environment affecting the CVF only to the
extent that it correlates with this quantity -- and that previous cluster
analyses may suffer from interloper contamination. These results serve as
useful benchmarks for cosmological simulations of galaxy formation.


title: A Tidal Flare Candidate in Abell 1795

abstract:
  As part of our ongoing archival X-ray survey of galaxy clusters for tidal
flares, we present evidence of an X-ray transient source within 1 arcmin of the
core of Abell 1795. The extreme variability (a factor of nearly 50), luminosity
(> 2 x 10^42 erg s^{-1}), long duration (> 5 years) and supersoft X-ray
spectrum (< 0.1 keV) are characteristic signatures of a stellar tidal
disruption event according to theoretical predictions and to existing X-ray
observations, implying a massive >~10^5 M_sun black hole at the centre of that
galaxy. The large number of X-ray source counts (~700) and long temporal
baseline (~12 years with Chandra and XMM-Newton) make this one of the
best-sampled examples of any tidal flare candidate to date. The transient may
be the same EUV source originally found contaminating the diffuse ICM
observations of Bowyer et al. (1999), which would make it the only tidal flare
candidate with reported EUV observations and implies an early source luminosity
1-2 orders of magnitude greater. If the host galaxy is a cluster member then it
must be a dwarf galaxy, an order of magnitude less massive than the quiescent
galaxy Henize 2-10 which hosts a massive black hole that is difficult to
reconcile with its low mass. The unusual faintness of the host galaxy may be
explained by tidal stripping in the cluster core.


title:
Cosmogenic nuclide enhancement via deposition from long-period comets as
  a test of the Younger Dryas impact hypothesis

abstract:
  We explore the idea that detectable excursions in 26Al may arise from direct
deposition by any bolide, and excursions in 14C and 10Be abundances in the
atmosphere may result from long-period comet impacts. This is very different
from the usual processes of production by cosmic rays within Earths atmosphere.
Long-period comets experience greatly increased cosmic ray flux beyond the
protection of the suns magnetic field. We report the computed amount of 14C,
10Be, and 26Al present on long-period comets as a function of comet mass. We
find that the amount of nuclide mass on large long-period comets entering the
Earths atmosphere may be sufficient for creating anomalies in the records of
14C and 10Be from past impacts. In particular, the estimated mass of the
proposed Younger Dryas comet is consistent with its having deposited sufficient
isotopes to account for recorded 14C and 10Be increases at that time. The
26Al/10Be ratio is much larger in extraterrestrial objects than in the
atmosphere, and so, we note that measuring this ratio in ice cores is a
suitable definitive test for the Younger Dryas impact hypothesis, even if the
hypothetical bolide is not a long-period comet and/or did not contribute to the
14C and 10Be increases.

categories: astro-ph.EP astro-ph.HE physics.ao-ph physics.geo-ph physics.space-ph


title:
Kepler observations of the eclipsing cataclysmic variable KIS
  J192748.53+444724.5

abstract:
  We present results from long cadence Kepler observations covering 97.6 days
of the newly discovered eclipsing cataclysmic variable KIS
J192748.53+444724.5/KIC 8625249. We detect deep eclipses of the accretion disk
by the donor star every 3.97 hours. Additionally, the Kepler observations also
cover a full outburst for this cataclysmic variable, making KIS
J192748.53+444724.5 the second known eclipsing cataclysmic variable system in
the Kepler field of view. We show how in quiescence a significant component
associated to the hot-spot is visible preceding the eclipse, and that this
component is swamped by the brightness increase during the outburst,
potentially associated with the accretion disk. Furthermore we present evidence
for accretion disk radius changes during the outburst by analysing the
out-of-eclipse light levels and eclipse depth through each orbital cycle. We
show how these parameters are linearly correlated in quiescence, and discuss
how their evolution during the outburst is suggesting disk radius changes
and/or radial temperature gradient variations in the disk.


title: The Optical Green Valley vs Mid-IR Canyon in Compact Groups

abstract:
  Compact groups of galaxies provide conditions similar to those experienced by
galaxies in the earlier universe. Recent work on compact groups has led to the
discovery of a dearth of mid-infrared transition galaxies (MIRTGs) in IRAC (3.6
- 8.0 micron) color space (Johnson et al. 2007; Walker et al. 2012) as well as
at intermediate specific star formation rates (Tzanavaris et al. 2010).
However, we find that in compact groups these mid-infrared (mid-IR) transition
galaxies in the mid-infrared dearth have already transitioned to the optical
([g-r]) red sequence. We investigate the optical color-magnitude diagram (CMD)
of 99 compact groups containing 348 galaxies and compare the optical CMD with
mid-IR color space for compact group galaxies. Utilizing redshifts available
from SDSS, we identified new galaxy members for 6 groups. By combining optical
and mid-IR data, we obtain information on both the dust and the stellar
populations in compact group galaxies. We also compare with more isolated
galaxies and galaxies in the Coma cluster, which reveals that, similar to
clusters, compact groups are dominated by optically red galaxies. While we find
that compact group transition galaxies lie on the optical red sequence,
LVL+SINGS mid-IR transition galaxies span the range of optical colors. The
dearth of mid-IR transition galaxies in compact groups may be due to a lack of
moderately star forming low mass galaxies; the relative lack of these galaxies
could be due to their relatively small gravitational potential wells. This
makes them more susceptible to this dynamic environment, thus causing them to
more easily lose gas or be accreted by larger members.


title:
Ultraviolet Emission-Line Correlations in Hubble/COS Spectra of Active
  Galactic Nuclei: Single-Epoch Black Hole Masses

abstract:
  Effective methods of measuring supermassive black hole masses in active
galactic nuclei (AGN) are of critical importance to studies of galaxy
evolution. While there has been much success obtaining masses through
reverberation mapping, the extensive observing time required by this method has
limited the practicality of applying it to large samples at a variety of
redshifts. This limitation highlights the need to estimate these masses using
single-epoch spectroscopy of ultraviolet emission lines. We use ultraviolet
spectra of 44 AGN from HST/COS, IUE, and FUSE of the CIV 1549, OVI 1035, OIII]
1664, HeII 1640, CII 1335, and MgII 2800 emission lines and explore their
potential as tracers of the broad-line region and supermassive black hole mass.
The higher S/N and better spectral resolution of the Cosmic Origins
Spectrograph on Hubble Space Telescope resolves AGN intrinsic absorption and
produces more accurate line widths. From these, we test the viability of
mass-scaling relationships based on line widths and luminosities and carry out
a principal component analysis based on line luminosities, widths, skewness,
and kurtosis. At L_{1450} < 10^{45} erg/s, the UV line luminosities correlate
well with Hbeta, as does the 1450 Angstrom continuum luminosity. We find that
CIV, OVI, and MgII can be used as reasonably accurate estimators of AGN black
hole masses, while HeII and CII are uncorrelated.


title: Carbon Monoxide in the Cold Debris of Supernova 1987A

abstract:
  We report spectroscopic and imaging observations of rotational transitions of
cold CO and SiO in the ejecta of SN1987A, the first such emission detected in a
supernova remnant. In addition to line luminosities for the CO J=1-0, 2-1, 6-5,
and 7-6 transitions, we present upper limits for all other transitions up to
J=13-12, collectively measured from the Atacama Large Millimeter Array (ALMA),
the Atacama Pathfinder EXperiment (APEX), and the Herschel Spectral and
Photometric Imaging REceiver (SPIRE). Simple models show the lines are emitted
from at least 0.01 solar masses of CO at a temperature > 14 K, confined within
at most 35% of a spherical volume expanding at ~ 2000 km/s. Moreover, we locate
the emission within 1'' of the central debris. These observations, along with a
partial observation of SiO, confirm the presence of cold molecular gas within
supernova remnants and provide insight into the physical conditions and
chemical processes in the ejecta. Furthermore, we demonstrate the powerful new
window into supernova ejecta offered by submillimeter observations.


title: Constraints on 2d CFT partition functions

abstract:
  Modular invariance is known to constrain the spectrum of 2d conformal field
theories. We investigate this constraint systematically, using the linear
functional method to put new improved upper bounds on the lowest gap in the
spectrum. We also consider generalized partition functions of N = (2,2)
superconformal theories and discuss the application of our results to
Calabi-Yau compactifications. For Calabi-Yau threefolds with no enhanced
symmetry we find that there must always be non-BPS primary states of weight 0.6
or less.


title:
The specific frequency and the globular cluster formation efficiency in
  Milgromian dynamics

abstract:
  Previous studies of globular cluster (GC) systems show that there appears to
be a universal specific GC formation efficiency $\eta$ which relates the total
mass of GCs to the virial mass of host dark matter halos, $M_{vir}$ (Georgiev
et al 2010, Spitler & Forbes2009). In this paper, the specific frequency,
$S_N$, and specific GC formation efficiency, $\eta$, are derived as functions
of $M_{vir}$ in Milgromian dynamics, i.e., in modified Newtonian dynamics
(MOND). In Milgromian dynamics, for the galaxies with GCs, the mass of the GC
system, $M_{GC}$, is a two-component function of $M_{vir}$ instead of a simple
linear relation. An observer in a Milgromian universe, who interprets this
universe as being Newtonian/Einsteinian, will incorrectly infer a universal
constant fraction between the mass of the GC system and a (false) dark matter
halo of the baryonic galaxy. In contrast to a universal constant of $\eta$, in
a Milgromian universe, for galaxies with $M_{vir} <= 10^{12}\msun$, $\eta$
decreases with the increase of $M_{vir}$, while for massive galaxies with
$M_{vir}>10^{12}\msun$, $\eta$ increases with the increase of $M_{vir}$.


title:
The preferentially magnified active nucleus in IRAS F10214+4724 - I.
  Lens model and spatially resolved radio emission

abstract:
  This is the first paper in a series that present a multi-wavelength analysis
of the archetype Ultra-Luminous InfraRed Galaxy (ULIRG) IRAS FSC10214+4724, a
gravitationally lensed, starburst/AGN at z=2.3. Here we present a new lens
model and spatially-resolved radio data, as well as a deep HST F160W map. The
lens modelling employs a Bayesian Markov Chain Monte Carlo algorithm with
extended-source, forward ray-tracing. Using these high resolution HST, MERLIN
and VLA maps, the algorithm allows us to constrain the level of distortion to
the continuum spectral energy distribution resulting from emission components
with differing magnification factors, due to their size and proximity to the
caustic. Our lens model finds the narrow line region (NLR), and by proxy the
active nucleus, is preferentially magnified. This supports previous claims that
preferential magnification could mask the expected polycyclic aromatic
hydrocarbon spectral features in the Spitzer mid-infrared spectrum which
roughly trace the star-forming regions. Furthermore, we show the
arc-to-counter-image flux ratio is not a good estimate of the magnification in
this system, despite its common use in the IRAS FSC10214+4724 literature. Our
lens modelling suggests magnifications of \mu ~ 15-20+-2 for the HST F814W,
MERLIN 1.7 GHz and VLA 8 GHz maps, significantly lower than the canonical
values of \mu = 50-100 often used for this system. Systematic errors such as
the dark matter density slope and co-location of stellar and dark matter
centroids dominate the uncertainties in the lens model at the 40 percent level.


title:
The preferentially magnified active nucleus in IRAS F10214+4724 - II.
  Spatially resolved cold molecular gas

abstract:
  We present JVLA observations of the cold (CO (1-0)) molecular gas in IRAS
F10214+4724, a lensed ULIRG at z=2.3 with an obscured active nucleus. The
galaxy is spatially and spectrally well-resolved in the CO (1-0) emission line.
A CO (1-0) counter-image is detected at the 3-sigma level. Five of the 42 km/s
channels (with >5-sigma detections) are mapped back into the source plane and
their total magnification posterior PDFs sampled. This reveals a roughly linear
arrangement, tentatively a rotating disk. We derive a molecular gas mass of
M_gas = 1.2 +- 0.2 x 10^10 M_sun, assuming a ULIRG L_{CO}-to-M_{gas} conversion
ratio of \alpha = 0.8 M_sun / (K km/s pc^2) that agrees well with the derived
range of \alpha = 0.3 - 1.3 for separate dynamical mass estimates at assumed
inclinations of i = 90 - 30 degrees. Based on the AGN and CO (1-0) peak
emission positions and the lens model, we predict a distortion of the CO
Spectral Line Energy Distribution (SLED) where higher order J lines that may be
partially excited by AGN heating will be preferentially lensed owing to their
smaller solid angles and closer proximity to the AGN and therefore the cusp of
the caustic. Comparison with other lensing inversion results shows that the
narrow line region and AGN radio core in IRAS F10214+4724 are preferentially
lensed by a factor >~ 3 and 11 respectively, relative to the molecular gas
emission. This distorts the global continuum emission Spectral Energy
Distribution (SED) and suggests caution in unsophisticated uses of IRAS
F10214+4724 as an archetype high-redshift ULIRG. We explore two Large Velocity
Gradient (LVG) models, incorporating spatial CO (1-0) and (3-2) information and
present tentative evidence for an extended, low excitation cold gas component
that implies that the total molecular gas mass in IRAS F10214+4724 is a factor
>~2 greater than that calculated using spatially unresolved CO observations.


title:
The preferentially magnified active nucleus in IRAS F10214+4724 - III.
  VLBI observations of the radio core

abstract:
  We report 1.7 GHz Very Long Baseline Interferometry (VLBI) observations of
IRAS F10214+4724, a lensed z=2.3 obscured quasar with prodigious star
formation. We detect what we argue to be the obscured active nucleus with an
effective angular resolution of < 50 pc at z = 2.3 . The S_{1.7} = 210 micro-Jy
(9-\sigma) detection of this unresolved source is located within the HST
rest-frame ultraviolet/optical arc, however, >~100 mas northward of the arc
centre of curvature. This leads to a source plane inversion that places the
European VLBI Network detection to within milli-arcseconds of the modelled cusp
caustic, resulting in a very large magnification (\mu ~70), over an order of
magnitude larger than the CO (1-0) derived magnification of a spatially
resolved JVLA map, using the same lens model. We estimate the quasar bolometric
luminosity from a number of independent techniques and with our X-ray modelling
find evidence that the AGN may be close to Compton-thick, with an intrinsic
bolometric luminosity log(L_{bol,QSO} / L_sun) = 11.34 +- 0.27 dex. We make the
first black hole mass estimate of IRAS F10214+4724 and find log(M_{BH}/M_sun) =
8.36 +- 0.56 which suggests a low black hole accretion rate (\lambda = \dot{M}
/ \dot{M}_{Edd} ~ 3\pm^7_2 percent). We find evidence for a M_{BH}/M_{spheroid}
ratio that is 1-2 orders of magnitude larger than that of submillimetre
galaxies (SMGs) at z~2. At face value, this suggests IRAS F10214+4724 has
undergone a different evolutionary path compared to SMGs at the same epoch. A
primary result of this work is the demonstration that emission regions of
differing size and position can undergo significantly different magnification
boosts (> 1 dex) and therefore distort our view of high-redshift,
gravitationally lensed galaxies.


title: Supersymmetry on curved spaces and superconformal anomalies

abstract:
  We study the consequences of unbroken rigid supersymmetry of four-dimensional
field theories placed on curved manifolds. We show that in Lorentzian signature
the background vector field coupling to the R-current is determined by the Weyl
tensor of the background metric. In Euclidean signature, the same holds if two
supercharges of opposite R-charge are preserved, otherwise the (anti-)self-dual
part of the vector field-strength is fixed by the Weyl tensor. As a result of
this relation, the trace and R-current anomalies of superconformal field
theories simplify, with the trace anomaly becoming purely topological. In
particular, in Lorentzian signature, or in the presence of two Euclidean
supercharges of opposite R-charge, supersymmetry of the background implies that
the term proportional to the central charge c vanishes, both in the trace and
R-current anomalies. This is equivalent to the vanishing of a superspace Weyl
invariant. We comment on the implications of our results for holography.


title: Decaying WIMP dark matter for AMS-02 cosmic positron excess

abstract:
  For explaining the AMS-02 cosmic positron excess, which was recently
reported, we consider a scenario of thermally produced and decaying dark matter
(DM) into the standard model (SM) leptons with an extremely small decay rate,
\Gamma_{DM} \sim 10^{-26} sec.^{-1}. Since the needed DM mass is relatively
heavy (700 GeV < m_{DM} < 3000 GeV), we introduce another DM component apart
from the lightest supersymmetric particle ("LSP"). For its (meta-) stability
and annihilation into other particles, the new DM should be accompanied with
another Z_2 symmetry apart from the R-parity. Sizable renormalizable couplings
of the new DM with SM particles, which are necessary for its thermalization in
the early universe, cannot destabilize the new DM because of the new Z_2
symmetry. Since the new DM was thermally produced, it can naturally explain the
present energy density of the universe. The new DM can decay into the SM
leptons (and the LSP) only through non-renormalizable operators suppressed by a
superheavy squared mass parameter after the new symmetry is broken around TeV
scale. We realize this scenario in a model of "gauged vector-like leptons,"
which was proposed recently for the naturalness of the Higgs boson.


title: Alignment of supermassive black hole binary orbits and spins

abstract:
  Recent studies of accretion onto supermassive black hole binaries suggest
that much, perhaps most, of the matter eventually accretes onto one hole or the
other. If so, then for binaries whose inspiral from ~1 pc to 0.001 - 0.01 pc is
driven by interaction with external gas, both the binary orbital axis and the
individual black hole spins can be reoriented by angular momentum exchange with
this gas. Here we show that, unless the binary mass ratio is far from unity,
the spins of the individual holes align with the binary orbital axis in a time
few-100 times shorter than the binary orbital axis aligns with the angular
momentum direction of the incoming circumbinary gas; the spin of the secondary
aligns more rapidly than that of the primary by a factor ~(m_1/m_2)^{1/2}>1.
Thus the binary acts as a stabilizing agent, so that for gas-driven systems,
the black hole spins are highly likely to be aligned (or counteraligned if
retrograde accretion is common) with each other and with the binary orbital
axis. This alignment can significantly reduce the recoil speed resulting from
subsequent black hole merger.


title: The 1st Fermi LAT SNR Catalog: Probing the Gamma-ray Population

abstract:
  While supernova remnants (SNRs) are widely thought to be powerful
accelerators, evidence comes largely from a small number of well-studied cases.
Here we systematically determine the gamma-ray emission from all known Galactic
SNRs, disentangling them from the sea of Galactic cosmic rays. Using Fermi LAT
data we have characterized the GeV emission in all regions containing SNRs,
accounting for systematic uncertainties caused by source confusion, diffuse
emission modeling, and instrumental response. More than a dozen remnants are
identified through spatial extension or detection at TeV energies, with
potential associations for >40 more. From this population study, two clear
classes of gamma-ray-emitting SNRs emerge: young remnants and those interacting
with a dense medium. This large statistical sample also reveals a possible
correlation between GeV and radio flux. The growing number of identified SNRs
will help to disentangle the effects of age and environment on the aggregate
properties of SNRs at high energies.


title: The 1st Fermi LAT SNR Catalog: Constraining the Cosmic Ray Contribution

abstract:
  Despite tantalizing evidence that supernova remnants (SNRs) are the source of
Galactic cosmic rays (CRs), including the recent detection of a spectral
signature of hadronic gamma-ray emission from two SNRs, their origin in
aggregate remains elusive. We address the long-standing question of Galactic CR
nuclei origins using our statistically significant GeV SNR sample to estimate
the contribution of SNRs to directly observed CRs. Interactions between CRs and
ambient gas near the SNRs emit photons via pion decay at GeV energies,
providing an in situ tracer for CRs otherwise measured directly with
balloon-borne and satellite experiments near the Earth. To date, the Fermi LAT
SNR Catalog has detected more than 50 SNRs and potential associations in
classes with a variety of properties, yet all remain possible accelerators. We
investigate the GeV and multiwavelength (MW) emission from SNRs to constrain
their maximal contribution to observed Galactic CRs. Our work demonstrates the
need for improvements to previously sufficient simple models describing the GeV
and MW emission from these objects.


title:
The 1st Fermi LAT SNR Catalog: the Impact of Interstellar Emission
  Modeling

abstract:
  Galactic interstellar emission contributes substantially to Fermi LAT
observations in the Galactic plane, the location of the majority of supernova
remnants (SNRs). To explore some systematic effects on SNRs' properties caused
by interstellar emission modeling, we have developed a method comparing the
official LAT interstellar emission model results to eight alternative models.
We created the eight alternative Galactic interstellar models by varying a few
input parameters to GALPROP, namely the height of the cosmic ray propagation
halo, cosmic ray source distribution in the Galaxy, and atomic hydrogen spin
temperature. We have analyzed eight representative SNRs chosen to encompass a
range of Galactic locations, extensions, and spectral properties using the
eight different interstellar emission models. We will present the results and
method in detail and discuss the implications for studies such as the 1st Fermi
LAT SNR Catalog.


title: An elementary proof of Franks' lemma for geodesic flows

abstract:
  Given a Riemannian manifold $(M,g)$ and a geodesic $\gamma$, the
perpendicular part of the derivative of the geodesic flow $\phi_g^t: SM
\rightarrow SM$ along $\gamma$ is a linear symplectic map. We give an
elementary proof of the following Franks' lemma, originally found in [G.
Contreras and G. Paternain, 2002] and [G. Contreras, 2010]: this map can be
perturbed freely within a neighborhood in $Sp(n)$ by a $C^2$-small perturbation
of the metric $g$ that keeps $\gamma$ a geodesic for the new metric. Moreover,
the size of these perturbations is uniform over fixed length geodesics on the
manifold. When $\dim M \geq 3$, the original metric must belong to a
$C^2$--open and dense subset of metrics.


title: Parallelizing Windowed Stream Joins in a Shared-Nothing Cluster

abstract:
  The availability of large number of processing nodes in a parallel and
distributed computing environment enables sophisticated real time processing
over high speed data streams, as required by many emerging applications.
Sliding window stream joins are among the most important operators in a stream
processing system. In this paper, we consider the issue of parallelizing a
sliding window stream join operator over a shared nothing cluster. We propose a
framework, based on fixed or predefined communication pattern, to distribute
the join processing loads over the shared-nothing cluster. We consider various
overheads while scaling over a large number of nodes, and propose solution
methodologies to cope with the issues. We implement the algorithm over a
cluster using a message passing system, and present the experimental results
showing the effectiveness of the join processing algorithm.


title: Cosmic ray acceleration in young supernova remnants

abstract:
  We investigate the appearance of magnetic field amplification resulting from
a cosmic ray escape current in the context of supernova remnant shock waves.
The current is inversely proportional to the maximum energy of cosmic rays, and
is a strong function of the shock velocity. Depending on the evolution of the
shock wave, which is drastically different for different circumstellar
environments, the maximum energy of cosmic rays as required to generate enough
current to trigger the non-resonant hybrid instability that confines the cosmic
rays follows a different evolution and reaches different values. We find that
the best candidates to accelerate cosmic rays to ~few PeV energies are young
remnants in a dense environment, such as a red supergiant wind, as may be
applicable to Cassiopeia A. We also find that for a typical background magnetic
field strength of 5 microG the instability is quenched in about 1000 years,
making SN1006 just at the border of candidates for cosmic ray acceleration to
high energies.


title:
Spreading Speeds and Traveling Waves of Nonlocal Monostable Equations in
  Time and Space Periodic Habitats

abstract:
  This paper is devoted to the investigation of spatial spreading speeds and
traveling wave solutions of monostable evolution equations with nonlocal
dispersal in time and space periodic habitats. It has been shown in an earlier
work by the first two authors of the current paper that such an equation has a
unique time and space periodic positive stable solution $u^*(t,x)$. In this
paper, we show that such an equation has a spatial spreading speed $c^*(\xi)$
in the direction of any given unit vector $\xi$. A variational characterization
of $c^*(\xi)$ is given. Under the assumption that the nonlocal dispersal
operator associated to the linearization of the monostable equation at the
trivial solution $0$ has a principal eigenvalue, we also show that the
monostable equation has a continuous periodic traveling wave solution
connecting $u^*(\cdot,\cdot)$ and $0$ propagating in any given direction of
$\xi$ with speed $c>c^*(\xi)$.


title: Nuclear polarization corrections in the mu-4He+ Lamb shift

abstract:
  Stimulated by the proton radius conundrum, measurements of the Lamb shift in
various light muonic atoms are planned at PSI. The aim is to extract the rms
charge radius with high precision, limited by the uncertainty in the nuclear
polarization corrections. We present an ab-initio calculation of the nuclear
polarization for mu-4He+ leading to an energy correction in the 2S-2P
transitions of $\delta_{pol}=-2.47$ meV $\pm$ 6%. We use two different
state-of-the-art nuclear Hamiltonians and utilize the Lorentz integral
transform with hyperspherical harmonics expansion as few-body methods. We take
into account the leading multipole contributions, plus Coulomb, relativistic
and finite-nucleon-size corrections. Our main source of uncertainty is the
nuclear Hamiltonian, which currently limits the attainable accuracy. Our
predictions considerably reduce the uncertainty with respect to previous
estimates and should timely serve the mu-4He+ experiment planned for 2013.


title:
Existence and symmetry for elliptic equations in R^n with arbitrary
  growth in the gradient

abstract:
  We study the semilinear elliptic equation $\Delta u + g(x,u,Du) = 0$ in
$\R^n$. The nonlinearities $g$ can have arbitrary growth in $u$ and $Du$,
including in particular the exponential behavior. No restriction is imposed on
the behavior of $g(x,z,p)$ at infinity except in the variable $x$. We obtain a
solution $u$ that is locally unique and inherits many of the symmetry
properties of $g$. Positivity and asymptotic behavior of the solution are also
addressed. Our results can be extended to other domains like half-space and
exterior domains. We give some examples.


title: Compressible impurity flow in the TJ-II stellarator

abstract:
  Fully-ionised carbon impurity flow is studied in ion-root, neutral beam
heated plasmas by means of Charge Exchange Recombination Spectroscopy (CXRS) in
the TJ-II stellarator. Perpendicular flows are found to be in reasonable
agreement with neoclassical calculations of the radial electric field. The
parallel flow of the impurity is obtained at two locations of the same flux
surface after subtraction of the calculated Pfirsch-Schl\"uter parallel
velocity. For the medium density plasmas studied, $\bar{n}_{\rm
e}\in(1.2-2.4)\times 10^{19}$ m$^{-3}$, the measured impurity flow is found to
be inconsistent with a total incompressible flow, i.e. $\nabla\cdot{\bf
u}_z\ne0$, thus contradicting the usual assumption of a constant density on
each flux surface. The experimentally observed velocity deviations are compared
with the parallel return flow calculated from a modelled impurity density
redistribution driven by ion-impurity friction. Although the calculated return
flow substantially modifies the incompressible velocity pattern, the
modifications do not explain the in-surface variations of impurity parallel
mass flow at the precise locations of the CXRS measurements. Small
inhomogeneities of the electrostatic potential in a surface are also shown to
affect the impurity redistribution but do not provide a better understanding of
the measurements.


title: A simple non-bisimple congruence-free finitely presented monoid

abstract:
  We exhibit an example of a finitely presented monoid that is congruence-free
and simple but not bisimple.


title: Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC (2013 update)

abstract:
  We present updated results on the complementarity between high-energy
colliders and dark matter direct detection experiments in the context of
Universal Extra Dimensions (UED). In models with relatively small mass
splittings between the dark matter candidate and the rest of the (colored)
spectrum, the collider sensitivity is diminished, but direct detection rates
are enhanced. UED provide a natural framework to study such mass degeneracies.
We discuss the detection prospects for the KK photon $\gamma_1$ and the KK
$Z$-boson $Z_1$, combining the expected LHC reach with cosmological constraints
from WMAP/Planck, and the sensitivity of current or planned direct detection
experiments. Allowing for general mass splittings, neither colliders, nor
direct detection experiments by themselves can explore all of the relevant KK
dark matter parameter space. Nevertheless, they probe different parameter space
regions, and the combination of the two types of constraints can be quite
powerful.


title: Open problems and conjectures on submanifolds of finite type revisited

abstract:
  Submanifolds of finite type were introduced by the author during the late
1970s. The first results on this subject had been collected in author's book
[Total mean curvature and sub manifolds of finite type, World Scientific, NJ,
1984]. A list of ten open problems and three conjectures on submanifolds of
finite type was published in 1981. The main purpose of this article is to
provide some updated information on the three conjectures.


title:
A Measure of Control for Secondary Cytokine-Induced Injury of Articular
  Cartilage: A Computational Study

abstract:
  In previous works, the author and collaborators establish a mathematical
model for injury response in articular cartilage. In this paper we use
mathematical software and computational techniques, applied to an existing
model to explore in more detail how the behavior of cartilage cells is
influenced by several of, what are believed to be, the most significant
mechanisms underlying cartilage injury response at the cellular level. We
introduce a control parameter, the radius of attenuation, and present some new
simulations that shed light on how inflammation associated with cartilage
injuries impacts the metabolic activity of cartilage cells. The details
presented in the work can help to elucidate targets for more effective
therapies in the preventative treatment of post-traumatic osteoarthritis.


title:
Globally aligned states and hydrodynamic traffic jams in confined active
  suspensions

abstract:
  Strongly confined active liquids are subject to unique hydrodynamic
interactions due to momentum screening and lubricated friction by the confining
walls. Using numerical simulations, we demonstrate that 2D dilute suspensions
of fore-aft asymmetric polar swimmers in a Hele-Shaw geometry can exhibit a
rich variety of novel phase behaviors depending on particle shape, including:
coherent polarized density waves with global alignment, stationary asters,
persistent counter-rotating vortices, density shocks and rarefaction waves. We
also explain these phenomena using a linear stability analysis and a nonlinear
traffic flow model, both derived from a mean-field kinetic theory.

categories: cond-mat.soft nlin.CD physics.bio-ph physics.flu-dyn


title:
The PTI Carbon Star Angular Size Survey: Effective Temperatures and
  Non-Sphericity

abstract:
  We report new interferometric angular diameter observations of 41 carbon
stars observed with the Palomar Testbed Interferometer (PTI). Two of these
stars are CH carbon stars and represent the first such measurements for this
subtype. Of these, 39 have Yamashita (1972,1975) spectral classes and are of
sufficiently high quality that we may determine the dependence of effective
temperature on spectral type. We find that there is a tendency for the
effective temperature to increase with increasing temperature index by ~120K
per step, starting at T_EFF ~= 2500K for C3,y, although there is a large amount
of scatter about this relationship. Overall, the median effective temperature
for the carbon star sample is found to be 2800 +- 270K, and the median linear
radius is 360 +- 100 R_SUN. We also find agreement on average within 15K with
the T_EFF determinations of Bergeat (2001,2002a,b), and a refinement of carbon
star angular size prediction based on V & K magnitudes is presented that is
good to an rms of 12%. A subsample of our stars have sufficient {u,v} coverage
to permit non-spherical modeling of their photospheres, and a general tendency
for detection of statistically significant departures from sphericity with
increasing signal-to-noise of the interferometric data is seen. The
implications of most - and potentially all - carbon stars being non-spherical
is considered in the context of surface inhomogeneities and a rotation-mass
loss connection.


title: GRB 120521C at z~6 and the Properties of High-redshift GRBs

abstract:
  We present optical, near-infrared, and radio observations of the afterglow of
GRB 120521C. By modeling the multi-wavelength dataset, we derive a photometric
redshift of z~6.0, which we confirm with a low signal-to-noise ratio spectrum
of the afterglow. We find that a model with a constant-density environment
provides a good fit to the afterglow data, with an inferred density of
0.05/cm^3. The radio observations reveal the presence of a jet break at 7 d,
corresponding to a jet opening angle of ~ 3 deg. The beaming-corrected
gamma-ray and kinetic energies are both ~ 3e50 erg. We quantify the
uncertainties in our results using a detailed Markov Chain Monte Carlo
analysis, which allows us to uncover degeneracies between the physical
parameters of the explosion. To compare GRB 120521C to other high-redshift
bursts in a uniform manner we re-fit all available afterglow data for the two
other bursts at z>6 with radio detections (GRBs 050904 and 090423). We find a
jet break at ~ 15 d for GRB 090423, in contrast to previous work. Based on
these three events, we find that GRBs at z>6 appear to explode in
constant-density environments, and exhibit a wide range of energies and
densities that span the range inferred for lower redshift bursts. On the other
hand, we find a hint for narrower jets in the z>6 bursts, potentially
indicating a larger true event rate at these redshifts. Overall, our results
indicate that long GRBs share a common progenitor population at least to z~8.


title:
First Measurement of the Electromagnetic Form Factor of the Neutral Kaon
  at a Large Momentum Transfer and the Effect of $SU(3)$ Breaking

abstract:
  At large momentum transfers the photon interacts with the charges and spins
of the constituent partons in a hadron. It is expected that the neutral kaon
can acquire finite electromagnetic form factors because its wave function is
affected by the order of magnitude difference between the mass of the strange
quark and that of the down quark, or flavor $SU(3)$ breaking. We report on the
first measurement of the form factor of neutral kaons at the large timelike
momentum transfer of $|Q^2|=17.4$ GeV$^2$ by measuring the cross section for
$e^+e^-\to K_SK_L$ at $\sqrt{s}=4.17$ GeV using CLEO-c data with an integrated
luminosity of 586 pb$^{-1}$. We obtain
$F_{K_SK_L}(17.4~\textrm{GeV}^2)=5.3\times10^{-3}$, with a 90% C.L. interval of
$(2.9-8.2)\times10^{-3}$. This is nearly an order of magnitude smaller than
$F_{K^+K^-}(17.4~\textrm{GeV}^2)=(44\pm1)\times10^{-3}$, and indicates that the
effect of $SU(3)$ breaking is small. In turn, this makes it unlikely that the
recently observed strong violation of the pQCD prediction,
$F_{\pi^+\pi^-}(|Q^2|)/F_{K^+K^-}(|Q^2|)=f_\pi^2/f_K^2$, which is based on the
assumption of similar wave functions for the pions and kaons, can be attributed
to $SU(3)$ breaking alone.


title:
Metal-Poor, Cool Gas in the Circumgalactic Medium of a z = 2.4
  Star-Forming Galaxy: Direct Evidence for Cold Accretion?

abstract:
  In our current galaxy formation paradigm, high-redshift galaxies are
predominantly fuelled by accretion of cool, metal-poor gas from the
intergalactic medium. Hydrodynamical simulations predict that this material
should be observable in absorption against background sightlines within a
galaxy's virial radius, as optically thick Lyman-limit systems (LLSs) with low
metallicities. Here we report the discovery of exactly such a strong metal-poor
absorber at an impact parameter R_perp = 58 kpc from a star-forming galaxy at z
= 2.44. Besides strong neutral hydrogen [N(HI) = 10^(19.50 +/- 0.16) cm^-2] we
detect neutral deuterium and oxygen, allowing a precise measurement of the
metallicity: log10(Z / Zsolar) = -2.0 +/- 0.17, or (7-15) x 10^-3 solar.
Furthermore, the narrow deuterium linewidth requires a cool temperature <
20,000 K. Given the striking similarities between this system and the
predictions of simulations, we argue that it represents the direct detection of
a high redshift cold-accretion stream. The low-metallicity gas cloud is a
single component of an absorption system exhibiting a complex velocity,
ionization, and enrichment structure. Two other components have metallicities >
0.1 solar, ten times larger than the metal-poor component. We conclude that the
photoionized circumgalactic medium (CGM) of this galaxy is highly
inhomogeneous: the majority of the gas is in a cool, metal-poor and
predominantly neutral phase, but the majority of the metals are in a
highly-ionized phase exhibiting weak neutral hydrogen absorption but strong
metal absorption. If such inhomogeneity is common, then high-resolution spectra
and detailed ionization modelling are critical to accurately appraise the
distribution of metals in the high-redshift CGM.


title: Type Ia supernovae observations do not show time dilation

abstract:
  The standard analysis for type Ia supernovae uses a set of templates to
overcome the intrinsic variation of the supernova light curves with wavelength.
This paper shows that standard templates contain an anomaly in that the width
of the template light curve is proportional to the emitted wavelength.
Furthermore this anomaly is exactly what would be produced if epoch differences
were not subject to time dilation and yet time dilation corrections were
applied. It is the specific nature of this anomaly that is evidence for a
static universe. The lack of time dilation is verified by direct analysis of
the original supernovae data.


title: A Theory of Partitioned Global Address Spaces

abstract:
  Partitioned global address space (PGAS) is a parallel programming model for
the development of applications on clusters. It provides a global address space
partitioned among the cluster nodes, and is supported in programming languages
like C, C++, and Fortran by means of APIs. In this paper we provide a formal
model for the semantics of single instruction, multiple data programs using
PGAS APIs. Our model reflects the main features of popular real-world APIs such
as SHMEM, ARMCI, GASNet, GPI, and GASPI.
  A key feature of PGAS is the support for one-sided communication: a node may
directly read and write the memory located at a remote node, without explicit
synchronization with the processes running on the remote side. One-sided
communication increases performance by decoupling process synchronization from
data transfer, but requires the programmer to reason about appropriate
synchronizations between reads and writes. As a second contribution, we propose
and investigate robustness, a criterion for correct synchronization of PGAS
programs. Robustness corresponds to acyclicity of a suitable happens-before
relation defined on PGAS computations. The requirement is finer than the
classical data race freedom and rules out most false error reports.
  Our main result is an algorithm for checking robustness of PGAS programs. The
algorithm makes use of two insights. Using combinatorial arguments we first
show that, if a PGAS program is not robust, then there are computations in a
certain normal form that violate happens-before acyclicity. Intuitively,
normal-form computations delay remote accesses in an ordered way. We then
devise an algorithm that checks for cyclic normal-form computations.
Essentially, the algorithm is an emptiness check for a novel automaton model
that accepts normal-form computations in streaming fashion. Altogether, we
prove the robustness problem is PSpace-complete.


title: Non-simple principally polarised abelian varieties

abstract:
  The paper investigates the locus of non-simple principally polarised abelian
$g$-folds. We show that the irreducible components of this locus are
$\Is^g_{D}$, defined as the locus of principally polarised $g$-folds having an
abelian subvariety with induced polarisation of type $D=(d_1,\ldots,d_k)$,
where $k\leq\frac{g}{2}$. The main theorem produces Humbert-like equations for
irreducible components of $\Is^g_{D}$ for any $g$ and $D$. Moreover, there are
theorems which characterise the Jacobians of curves that are \'etale double
covers or double covers branched in two or four points.


title: Entanglement spectroscopy of SU(2)-broken phases in two dimensions

abstract:
  In magnetically ordered systems the breaking of SU(2) symmetry in the
thermodynamic limit is associated with the appearance of a special type of
low-lying excitations in finite size energy spectra, the so called tower of
states (TOS). In the present work we numerically demonstrate that there is a
correspondence between the SU(2) tower of states and the lower part of the
ground state entanglement spectrum (ES). Using state-of-the-art DMRG
calculations, we examine the ES of the 2D antiferromagnetic J1-J2 Heisenberg
model on both the triangular and kagom\'e lattice. At large ferromagnetic J2
the model exhibits a magnetically ordered ground state. Correspondingly, its ES
contains a family of low-lying levels that are reminiscent of the energy tower
of states. Their behavior (level counting, finite size scaling in the
thermodynamic limit) sharply reflects tower of states features, and is
characterized in terms of an effective entanglement Hamiltonian that we
provide. At large system sizes TOS levels are divided from the rest by an
entanglement gap. Our analysis suggests that (TOS) entanglement spectroscopy
provides an alternative tool for detecting and characterizing SU(2)-broken
phases using DMRG.


title:
Using [CI] to probe the Interstellar Medium in z~2.5 Sub-Millimeter
  Galaxies

abstract:
  We present new [CI](1-0) and 12CO(4-3) Plateau de Bure Interferometer
observations of five Sub-Millimeter Galaxies (SMGs) and combine these with all
available [CI](1-0) literature detections in SMGs to probe the gas distribution
within a sample of 14 systems. We explore the [CI](1-0) properties of the SMG
population, particularly investigating the ratio of the [CI](1-0) luminosity to
various 12CO transition and far-infrared luminosities. We find that the SMGs
with new observations extend the spread of L[CI](1-0)/LFIR to much higher
values than found before, with our complete sample providing a good
representation of the diverse z>2 SMG population. We compare the line ratios to
the outputs of photodissociation region (PDR) models to constrain the average
density (n) and radiation field (in terms of the local field value, G0) of the
SMGs. We find the SMGs are most comparable to local ULIRGs in G0 and n, however
a significant tail of 5 of the 14 SMGs are likely best compared to less
compact, local starburst galaxies, providing new evidence that many SMGs have
extended star formation distributions and are therefore not simply scaled up
versions of local ULIRGs. We explore the limitations of using simple PDR models
to understand [CI], which may be concomitant with the bulk H2 mass rather than
PDR-distributed. We therefore also assess [CI] as a tracer of H2, finding that
for our sample SMGs, the H2 masses derived from [CI] are often consistent with
those determined from low excitation 12CO. We conclude that [CI] observations
provide a useful tool to probe the bulk gas and gas processes occurring within
merging SMGs, however more detailed, resolved observations are required to
fully exploit [CI] as a diagnostic.


title: Robust forward simulations of recurrent hitchhiking

abstract:
  Evolutionary forces shape patterns of genetic diversity within populations
and contribute to phenotypic variation. In particular, recurrent positive
selection has attracted significant interest in both theoretical and empirical
studies. However, most existing theoretical models of recurrent positive
selection cannot easily incorporate realistic confounding effects such as
interference between selected sites, arbitrary selection schemes, and
complicated demographic processes. It is possible to quantify the effects of
arbitrarily complex evolutionary models by performing forward population
genetic simulations, but forward simulations can be computationally prohibitive
for large population sizes ($> 10^5$). A common approach for overcoming these
computational limitations is rescaling of the most computationally expensive
parameters, especially population size. Here, we show that ad hoc approaches to
parameter rescaling under the recurrent hitchhiking model do not always provide
sufficiently accurate dynamics, potentially skewing patterns of diversity in
simulated DNA sequences. We derive an extension of the recurrent hitchhiking
model that is appropriate for strong selection in small population sizes, and
use it to develop a method for parameter rescaling that provides the best
possible computational performance for a given error tolerance. We perform a
detailed theoretical analysis of the robustness of rescaling across the
parameter space. Finally, we apply our rescaling algorithms to parameters that
were previously inferred for Drosophila, and discuss practical considerations
such as interference between selected sites.


title: Models of true arithmetic are integer parts of nice real closed fields

abstract:
  Exploring further the connection between exponentiation on real closed fields
and the existence of an integer part modelling strong fragments of arithmetic,
we demonstrate that each model of true arithmetic is an integer part of an
exponential real closed field that is elementary equivalent to the reals with
exponentiation.


title: Motivic Hopf elements and relations

abstract:
  We use Cayley-Dickson algebras to produce Hopf elements eta, nu and sigma in
the motivic stable homotopy groups of spheres, and we prove via geometric
arguments that the the products eta*nu and nu*sigma both vanish. Along the way
we develop several basic facts about the motivic stable homotopy ring.


title: Changing quantum reference frames

abstract:
  We consider the process of changing reference frames in the case where the
reference frames are quantum systems. We find that, as part of this process,
decoherence is necessarily induced on any quantum system described relative to
these frames. We explore this process with examples involving reference frames
for phase and orientation. Quantifying the effect of changing quantum reference
frames serves as a first step in developing a relativity principle for theories
in which all objects including reference frames are necessarily quantum.


title: The PBW property for associative algebras as an integrability condition

abstract:
  We develop an elementary method for proving the PBW theorem for associative
algebras with an ascending filtration. The idea is roughly the following. At
first, we deduce a proof of the PBW property for the {\it ascending} filtration
(with the filtered degree equal to the total degree in $x_i$'s) to a suitable
PBW-like property for the {\it descending} filtration (with the filtered degree
equal to the power of a polynomial parameter $\hbar$, introduced to the
problem). This PBW property for the descending filtration guarantees the
genuine PBW property for the ascending filtration, for almost all
specializations of the parameter $\hbar$. At second, we develop some very
constructive method for proving this PBW-like property for the descending
filtration by powers of $\hbar$, emphasizing its integrability nature.
  We show how the method works in three examples. As a first example, we give a
proof of the classical Poincar\'{e}-Birkhoff-Witt theorem for Lie algebras. As
a second, much less trivial example, we present a new proof of a result of
Etingof and Ginzburg [EG] on PBW property of algebras with a cyclic
non-commutative potential in three variables. Finally, as a third example, we
found a criterium, for a general quadratic algebra which is the
quotient-algebra of $T(V)[\hbar]$ by the two-sided ideal, generated by
$(x_i\otimes x_j-x_j\otimes x_i-\hbar\phi_{ij})_{i,j}$, with $\phi_{ij}$
general quadratic non-commutative polynomials, to be a PBW for generic
specialization $\hbar=a$. This result seems to be new.


title: Towards a Church-Turing-Thesis for Infinitary Computations

abstract:
  We consider the question whether there is an infinitary analogue of the
Church-Turing-thesis. To this end, we argue that there is an intuitive notion
of transfinite computability and build a canonical model, called Idealized
Agent Machines ($IAM$s) of this which will turn out to be equivalent in
strength to the Ordinal Turing Machines defined by P. Koepke.


title: Low-Temperature Phonoemissive Tunneling Rates in Single Molecule Magnets

abstract:
  Tunneling between the two lowest energy levels of single molecule magnets
with Ising type anisotropy, accompanied by the emission or absorption of
phonons, is considered. Quantitatively accurate calculations of the rates for
such tunneling are performed for a model Hamiltonian especially relevant to the
best studied example, \Fe8. Two different methods are used: high-order
perturbation theory in the spin-phonon interaction and the non-Ising-symmetric
parts of the spin Hamiltonian, and a novel semiclassical approach based on
spin-coherent-state-path-integral instantons. The methods are found to be in
good quantitative agreement with other, and consistent with previous approaches
to the problem. The implications of these results for magnetization of
molecular solids of these molecules are discussed briefly.


title:
Enhancement of NEST Capabilities for Simulating Low-Energy Recoils in
  Liquid Xenon

abstract:
  The Noble Element Simulation Technique (NEST) is an exhaustive collection of
models explaining both the scintillation light and ionization yields of noble
elements as a function of particle type (nuclear recoil, electron recoil,
alphas), electric field, and incident energy or energy loss dE/dx. It is
packaged as C++ code for Geant4 that implements said models, overriding the
default model which does not account for certain complexities, such as the
reduction in yields for nuclear recoils (NR) compared to electron recoils (ER).
We present here improvements to the existing NEST models and updates to the
code which make the package even more realistic and turn it into a more
full-fledged Monte Carlo simulation. All available liquid xenon data on NR and
ER to date have been taken into consideration in arriving at the current
models. Furthermore, NEST addresses the question of the magnitude of the light
and charge yields of nuclear recoils, including their electric field
dependence, thereby shedding light on the possibility of detection or exclusion
of a low-mass dark matter WIMP by liquid xenon detectors.


title: Improved Limits on Long-Range Parity-Odd Interactions of the Neutron

abstract:
  We show that a previous polarized 3He experiment at Princeton, plus Eot-Wash
equivalence-principle tests, constrain exotic, long-ranged (lambda > 0.15m)
parity-violating interactions of neutrons at levels well below those inferred
from a recent study of the parity-violating spin-precession of neutrons
transmitted through liquid 4He. For lambda > 1.0e8 meters the bounds on gAgV
are improved by a 11 orders of magnitude.


title:
Gravitational Collapse In Husain Space-time For Brans-Dicke Gravity
  Theory with Power-law Potential

abstract:
  The motive of this work is to study gravitational collapse in Husain
space-time in Brans-Dicke gravity theory. Among many scalar-tensor theories of
gravity, Brans-Dicke is the simplest and the impact of it can be regulated by
two parameters associated with it, namely, the Brans-Dicke parameter, $\omega$,
and the potential-scalar field dependency parameter $n$ respectively. V.
Husain's work on exact solution for null fluid collapse in 1996 has influenced
many authors to follow his way to find the end-state of the
homogeneous/in-homogeneous dust cloud. Vaidya's metric is used all over to
follow the nature of future outgoing radial null geodesics. Detecting whether
the central singularity is naked or wrapped by an event horizon, by the
existence of future directed radial null geodesic emitted in past from the
singularity is the basic objective. To point out the existence of positive
trajectory tangent solution, both particular parametric cases(through tabular
forms) and wide range contouring process have been applied. Precisely, perfect
fluid's EoS satisfies a wide range of phenomena : from dust to exotic fluid
like dark energy. We have used the EoS parameter $k$ to determine the end state
of collapse in different cosmological era. Our main target is to check low
$\omega$ (more deviations from Einstein gravity-more Brans Dicke effect) and
negative $k$ zones. This particularly throws light on the nature of the
end-state of collapse in accelerated expansion in Brans Dicke gravity. It is
seen that for positive values of EoS parameter $k$, the collapse results in a
black hole, whereas for negative values of $k$, naked singularity is the only
outcome. It is also to be noted that "low $\omega$" leads to the possibility of
getting more naked singularities even for a non-accelerating universe.


title:
Visualization of a particle's wave function in the double slits
  experiment

abstract:
  The double slits experiment is a basic phenomenon, which allows to explain
principal behaviour of quantum systems. However, textbooks present static
pictures of corresponding interference patterns. At the same time, modern
computer software for PDE solution provides an opportunity for dynamical
modeling of a wave function behaviour using a numerical solution of
Schroedinger's equation and to use the obtained demonstrations in a teaching of
physics. This material presents such a dynamical animated simulation.


title: Phase inversion and collapse of the cross-spectral function

abstract:
  Cross-spectral analysis is a mathematical tool for extracting the power
spectral density of a correlated signal from two time series in the presence of
uncorrelated interfering signals. We demonstrate and explain a set of
conditions where the detection of the desired signal using cross-spectral fails
partially or entirely in the presence of a second uncorrelated signal. Not
understanding when and how this effect occurs can lead to dramatic
underreporting of the desired signal. Theoretical, simulated and experimental
demonstrations of this effect as well as mitigating methods are presented.


title: Counting Square Discriminants

abstract:
  Counting integral binary quadratic forms with certain restrictions is a
classical problem. In this paper, we count binary quadratic forms of fixed
discriminant given restrictions on the size of their coefficients. We
accomplish this by investigating the analytic properties of a certain double
Dirichlet series, which is a shifted convolution sum of certain classical
automorphic forms.


title: Steady-state Physics, Effective Temperature Dynamics in Holography

abstract:
  Using the gauge-gravity duality, we argue that for a certain class of
out-of-equilibrium steady-state systems in contact with a thermal background at
a given temperature, the macroscopic physics can be captured by an effective
thermodynamic description. The steady-state is obtained by applying a constant
electric field that results in a stationary current flow. Within holography, we
consider generic probe systems where an open string equivalence principle and
an open string metric govern the effective thermodynamics. This description
comes equipped with an effective temperature, which is larger than the
background temperature, and a corresponding effective entropy. For conformal or
scale-invariant theories, certain scaling behaviours follow immediately. In
general, in the large electric field limit, this effective temperature is also
observed to obey generic relations with various physical parameters in the
system.


title:
Comparing Dawn, Hubble Space Telescope, and Ground-Based Interpretations
  of (4) Vesta

abstract:
  Observations of asteroid 4 Vesta by NASA's Dawn spacecraft are interesting
because its surface has the largest range of albedo, color and composition of
any other asteroid visited by spacecraft to date. These hemispherical and
rotational variations in surface brightness and composition have been
attributed to impact processes since Vesta's formation. Prior to Dawn's arrival
at Vesta, its surface properties were the focus of intense telescopic
investigations for nearly a hundred years. Ground-based photometric and
spectroscopic observations first revealed these variations followed later by
those using Hubble Space Telescope. Here we compare interpretations of Vesta's
rotation period, pole, albedo, topographic, color, and compositional properties
from ground-based telescopes and HST with those from Dawn. Rotational spectral
variations observed from ground-based studies are also consistent with those
observed by Dawn. While the interpretation of some of these features was
tenuous from past data, the interpretations were reasonable given the
limitations set by spatial resolution and our knowledge of Vesta and HED
meteorites at that time. Our analysis shows that ground-based and HST
observations are critical for our understanding of small bodies and provide
valuable support for ongoing and future spacecraft missions.

categories: astro-ph.EP astro-ph.IM physics.geo-ph physics.ins-det physics.space-ph


title: Compression for Quadratic Similarity Queries

abstract:
  The problem of performing similarity queries on compressed data is
considered. We focus on the quadratic similarity measure, and study the
fundamental tradeoff between compression rate, sequence length, and reliability
of queries performed on compressed data. For a Gaussian source, we show that
queries can be answered reliably if and only if the compression rate exceeds a
given threshold - the identification rate - which we explicitly characterize.
Moreover, when compression is performed at a rate greater than the
identification rate, responses to queries on the compressed data can be made
exponentially reliable. We give a complete characterization of this exponent,
which is analogous to the error and excess-distortion exponents in channel and
source coding, respectively.
  For a general source we prove that, as with classical compression, the
Gaussian source requires the largest compression rate among sources with a
given variance. Moreover, a robust scheme is described that attains this
maximal rate for any source distribution.


title:
Information bounds for inverse problems with application to
  deconvolution and L\'evy models

abstract:
  If a functional in an inverse problem can be estimated with parametric rate,
then the minimax rate gives no information about the ill-posedness of the
problem. To have a more precise lower bound, we study semiparametric efficiency
in the sense of H\'ajek-Le Cam for functional estimation in regular indirect
models. These are characterized as models that can be locally approximated by a
linear white noise model that is described by the generalized score operator. A
convolution theorem for regular indirect models is proved. This applies to a
large class of statistical inverse problems, which is illustrated for the
prototypical white noise and deconvolution model. It is especially useful for
nonlinear models. We discuss in detail a nonlinear model of deconvolution type
where a L\'evy process is observed at low frequency, concluding an information
bound for the estimation of linear functionals of the jump measure.


title: A single-oscillator quantum model for magnetochiral birefringence

abstract:
  We derive an analytical expression for the magnetochiral birefringence of a
dilute diamagnetic chiral molecular medium subjet to a constant magnetic field.
We use the single-oscillator model of Condon et al. [1, 2] to describe the
optical properties of the individual molecules. The result is a function of the
refractive index and the rotatory power. This result is compared to
experimental data.


title: Exact results in N=2 gauge theories

abstract:
  We derive exact formulae for the partition function and the expectation
values of Wilson/'t Hooft loops, thus directly checking their S-duality
transformations. We focus on a special class of N=2 gauge theories on S^4 with
fundamental matter. In particular we show that, for a specific choice of the
masses, the matrix model integral defining the gauge theory partition function
localizes around a finite set of critical points where it can be explicitly
evaluated and written in terms of generalized hypergeometric functions. From
the AGT perspective the gauge theory partition function, evaluated with this
choice of masses, is viewed as a four point correlator involving the insertion
of a degenerated field. The well known simplicity of the degenerated correlator
reflects the fact that for these choices of masses only a very restrictive type
of instanton configurations contributes to the gauge theory partition function.


title: Magnetic responses of randomly depleted spin ladders

abstract:
  The magnetic responses of a spin-1/2 ladder doped with non-magnetic
impurities are studied using various methods and including the regime where
frustration induces incommensurability. Several improvements are made on the
results of the seminal work of Sigrist and Furusaki [J. Phys. Soc. Jpn. 65,
2385 (1996)]. Deviations from the Brillouin magnetic curve due to interactions
are also analyzed. First, the magnetic profile around a single impurity and
effective interactions between impurities are analyzed within the bond-operator
mean-field theory and compared to density-matrix renormalization group
calculations. Then, the temperature behavior of the Curie constant is studied
in details. At zero-temperature, we give doping-dependent corrections to the
results of Sigrist and Furusaki on general bipartite lattice and compute
exactly the distribution of ladder cluster due to chain breaking effects. Using
exact diagonalization and quantum Monte-Carlo methods on the effective model,
the temperature dependence of the Curie constant is compared to a random dimer
model and a real-space renormalization group scenario. Next, the low-part of
the magnetic curve corresponding to the contribution of impurities is computed
using exact diagonalization. The random dimer model is shown to capture the
bulk of the curve, accounting for the deviation from the Brillouin response. At
zero-temperature, the effective model prediction agrees relatively well with
density-matrix renormalization group calculations. Finite-temperature effects
are displayed within the effective model and for large depleted ladder models
using quantum Monte-Carlo simulations. In all, the effect of incommensurability
does not display a strong qualitative effect on both the magnetic
susceptibility and the magnetic curve. Consequences for experiments on the
BiCu2PO6 compound and other spin-gapped materials are briefly discussed.