title: Coherent Nonlinear Quantum Model for Composite Fermions

abstract:
  Originally proposed by Read [1] and Jain [2], the so-called
"composite-fermion" is a phenomenological attachment of two infinitely thin
local flux quanta seen as nonlocal vortices to two-dimensional (2D) electrons
embedded in a strong orthogonal magnetic field. In this letter, it is described
as a highly-nonlinear and coherent mean-field quantum process of the soliton
type by use of a 2D stationary Schroedinger-Poisson differential model with
only two Coulomb-interacting electrons. At filling factor $\nu={1}{3}$ of the
lowest Landau level, it agrees with both the exact two-electron antisymmetric
Schroedinger wave function and Laughlin's Jastrow-type guess for the fractional
quantum Hall effect, hence providing this later with a tentative physical
justification based on first principles.


title:
On the complementarity of galaxy clustering with cosmic shear and flux
  magnification

abstract:
  In this paper, we motivate the use of galaxy clustering measurements using
photometric redshift information, including a contribution from flux
magnification, as a probe of cosmology. We present cosmological forecasts when
clustering data alone is used, and when clustering is combined with a cosmic
shear analysis. We consider two types of clustering analysis: firstly,
clustering with only redshift auto-correlations in tomographic redshift bins;
secondly, using all available redshift bin correlations. Finally, we consider
how inferred cosmological parameters may be biased using each analysis when
flux magnification is neglected. Results are presented for a Stage III
ground-based survey, and a Stage IV space-based survey modelled with
photometric redshift errors, and values for the slope of the luminosity
function inferred from CFHTLenS catalogues. We find that combining clustering
information with shear can improve constraints on cosmological parameters,
giving an improvement to a Dark Energy Task Force-like figure of merit by a
factor of 1.33 when only auto-correlations in redshift are used for the
clustering analysis, rising to 1.52 when cross-correlations in redshift are
also included. The addition of galaxy-galaxy lensing gives further improvement,
with increases in figure of merit by a factor of 2.82 and 3.7 for each type of
clustering analysis respectively. The presence of flux magnification in a
clustering analysis does not significantly affect the precision of cosmological
constraints when combined with cosmic shear and galaxy-galaxy lensing. However
if magnification is neglected, inferred cosmological parameter values are
biased, with biases in some cosmological parameters larger than statistical
errors. (Abridged)


title:
Effect of magnetic field on competition between superconductivity and
  charge order below the pseudogap state

abstract:
  We theoretically investigate the T-B phase diagram of cuprates building on
the SU(2) pseudogap order recently obtained from the spin-fermion model. At low
temperatures, our analysis reveals an almost temperature-independent critical
magnetic field B_{QDW} at which d-wave superconductivity switches to the
quadrupole density wave (QDW) phase. For temperatures beyond a certain value of
the order of the zero-field superconducting transition temperature T_c, the
critical field B_{QDW}(T) sharply grows. We compare our results derived within
the effective SU(2) non-linear sigma-model with the phase diagram recently
obtained by sound velocity measurements by LeBoeuf et al. [Nat. Phys. 9, 79
(2013)].


title: Large-scale anomalies from primordial dissipation

abstract:
  We analyze an inflationary model in which part of the power in density
perturbations arises due to particle production. The amount of particle
production is modulated by an auxiliary field. Given an initial gradient for
the auxiliary field, this model produces a hemispherical power asymmetry and a
suppression of power at low multipoles similar to those observed by WMAP and
Planck in the CMB temperature. It also predicts an additive contribution to
$\delta T$ with support only at very small $l$ that is aligned with the
direction of the power asymmetry and has a definite sign, as well as small
oscillations in the power spectrum at all $l$.


title: Quantum discord and remote state preparation

abstract:
  The role played by quantum discord in mixed-state computation is widely
debated since, in spite of evidence of its importance in creating quantum
advantages, even in the absence of entanglement, there are not direct proofs of
its necessity in these computational tasks. Recently the presence of discord
was shown to be necessary and sufficient for remote state preparation for a
broad class of quantum channels [B. Daki\'c et al., Nat. Phys. 8, 666 (2012)].
Here, we show that this property is not universal. There are states whose
discord cannot be considered as a quantum resource, since it has been produced
locally, that are useful for remote state preparation, and there are bona fide
discordant states that are of no help.


title:
Reconstruction from blind experimental data for an inverse problem for a
  hyperbolic equation

abstract:
  We consider the problem of reconstruction of dielectrics from blind
backscattered experimental data. Experimental data were collected by a device,
which was built at University of North Carolina at Charlotte. This device sends
electrical pulses into the medium and collects the time resolved backscattered
data on a part of a plane. The spatially distributed dielectric constant
$\varepsilon_{r}(\mathbf{x}),\mathbf{x}\in \mathbb{R}^{3}$ is the unknown
coefficient of a wave-like PDE. This coefficient is reconstructed from those
data in blind cases. To do this, a globally convergent numerical method is
used.


title: Influence of device geometry on tunneling in \nu=5/2 quantum Hall liquid

abstract:
  Two recent experiments [I. P. Radu et al., Science 320, 899 (2008) and X. Lin
et al., Phys. Rev. B 85, 165321 (2012)] measured the temperature and voltage
dependence of the quasiparticle tunneling through a quantum point contact in
the \nu= 5/2 quantum Hall liquid. The results led to conflicting conclusions
about the nature of the quantum Hall state. In this paper, we show that the
conflict can be resolved by recognizing different geometries of the devices in
the experiments. We argue that in some of those geometries there is significant
unscreened electrostatic interaction between the segments of the quantum Hall
edge on the opposite sides of the point contact. Coulomb interaction affects
the tunneling current. We compare experimental results with theoretical
predictions for the Pfaffian, SU(2)_2, 331 and K=8 states and their
particle-hole conjugates. After Coulomb corrections are taken into account,
measurements in all geometries agree with the spin-polarized and
spin-unpolarized Halperin 331 states.


title: The Higgs sector of the 4DCHM after the XLVIII Rencontres de Moriond

abstract:
  In this proceeding, we present the current status of a $\chi^2$ fit extracted
from the profiling of the Higgs couplings performed at the LHC in the context
of the 4-Dimensional Composite Higgs Model. Especially, we consider the data
presented by the ATLAS and CMS collaborations during the XLVIII Rencontres de
Moriond.


title:
Equation of State and Constitutive Models for Numerical Simulations of
  Dust Impacts on the Solar Probe

abstract:
  This report presents new EOS and strength models for use in numerical
hydrocode simulations of dust impacts on the NASA solar probe space vehicle.
This spacecraft will be subjected to impact at velocities up to 300 km/s,
producing pressures as high as 100 TPa and temperatures as high as 200 eV.
Hence the material models must treat a variety of physical and chemical
phenomena, including solid-solid transitions, melting and vaporization,
chemical reactions, electronic excitation and ionization. The EOSPro code is
used to develop tabular EOS that include these effects. The report discusses
the theoretical methods used to create the new EOS tables and constitutive
models for six materials--Al2O3, two porous carbon materials, fused SiO2, a
silicone elastomer, and germanium--which will be used in the thermal protection
shield (TPS) and solar cells, the components most vulnerable to dust impacts.
It also presents the results of hydrocode simulations of dust impacts on the
TPS and on glass targets. It discusses the importance of radiation
contributions to the EOS and the importance of reactions between Al2O3 and
carbon during impacts. It makes recommendations for additional work, including
experiments for testing the accuracy and reliability of the hydrocode
simulations as well as for improving and calibrating the material models.

categories: astro-ph.EP astro-ph.IM cond-mat.mtrl-sci physics.chem-ph physics.space-ph


title: Decay of eigenfunctions of elliptic PDE's

abstract:
  We study exponential decay of eigenfunctions of self-adjoint higher order
elliptic operators on $\R^d$. We show that the possible critical decay rates
are determined algebraically. In addition we show absence of
super-exponentially decaying eigenfunctions and a refined exponential upper
bound.


title: Running quark and lepton parameters at various scales

abstract:
  We calculate the values and 1 sigma ranges of the running quark and lepton
Yukawa couplings as well as of the quark mixing parameters at various energy
scales, i.e. at M_Z, 1 TeV, 3 TeV, 10 TeV and at the GUT scale, to provide
useful input for model building. Above TeV energies, we assume the minimal
supersymmetric extension of the Standard Model, and include the
tan(beta)-enhanced one-loop supersymmetric threshold corrections which arise
when matching the SM to its SUSY extension. We calculate the GUT scale values
of the running parameters as well as their 1 sigma ranges, with the
supersymmetric threshold corrections included and with their effects
parametrised in a simple way.


title:
Lyapunov Functions in Piecewise Linear Systems: From Fixed Point to
  Limit Cycle

abstract:
  This paper provides a first example of constructing Lyapunov functions in a
class of piecewise linear systems with limit cycles. The method of construction
helps analyze and control complex oscillating systems through novel geometric
means. Special attention is stressed upon a problem not formerly solved: to
impose consistent boundary conditions on the Lyapunov function in each linear
region. By successfully solving the problem, the authors construct continuous
Lyapunov functions in the whole state space. It is further demonstrated that
the Lyapunov functions constructed explain for the different bifurcations
leading to the emergence of limit cycle oscillation.


title: The inside-out view on neutron star magnetospheres

abstract:
  We construct hydromagnetic neutron star equilibria which allow for a non-zero
electric current distribution in the exterior. The novelty of our models is
that the neutron star's interior field is in equilibrium with its
magnetosphere, thus bridging the gap between previous work in this area which
either solves for the interior assuming a vacuum exterior or solves for the
magnetosphere without modelling the star itself. We consider only non-rotating
stars in this work, so our solutions are most immediately applicable to
slowly-rotating systems such as magnetars. Nonetheless, we demonstrate that
magnetospheres qualitatively resembling those expected for both magnetars and
pulsars are possible within our framework. The "inside-out" approach taken in
this paper should be more generally applicable to rotating neutron stars, where
the interior and exterior regions are again not independent but evolve
together.


title: Pseudopotentials for correlated electron systems

abstract:
  A scheme is developed for creating pseudopotentials for use in
correlated-electron calculations. Pseudopotentials for the light elements H,
Li, Be, B, C, N, O, and F, are reported, based on data from high-level quantum
chemical calculations. Results obtained with these correlated electron
pseudopotentials (CEPPs) are compared with data for atomic energy levels and
the dissociation energies, molecular geometries and zero-point vibrational
energies of small molecules obtained from coupled cluster single double triple
(CCSD(T)) calculations with large basis sets. The CEPPs give better results in
correlated-electron calculations than Hartree-Fock-based pseudopotentials
available in the literature.


title: pyro: A teaching code for computational astrophysical hydrodynamics

abstract:
  We describe pyro: a simple, freely-available code to aid students in learning
the computational hydrodynamics methods widely used in astrophysics. pyro is
written with simplicity and learning in mind and intended to allow students to
experiment with various methods popular in the field, including those for
advection, compressible and incompressible hydrodynamics, multigrid, and
diffusion in a finite-volume framework. We show some of the test problems from
pyro, describe its design philosophy, and suggest extensions for students to
build their understanding of these methods.


title:
Intrinsic atomic orbitals: An unbiased bridge between quantum theory and
  chemical concepts

abstract:
  Modern quantum chemistry can make quantitative predictions on an immense
array of chemical systems. However, the interpretation of those predictions is
often complicated by the complex wave function expansions used. Here we show
that an exceptionally simple algebraic construction allows for defining atomic
core and valence orbitals, polarized by the molecular environment, which can
exactly represent self-consistent field wave functions. This construction
provides an unbiased and direct connection between quantum chemistry and
empirical chemical concepts, and can be used, for example, to calculate the
nature of bonding in molecules, in chemical terms, from first principles.


title:
Galactic electron and positron properties from cosmic ray and radio
  observations

abstract:
  We perform a consistent modeling of cosmic ray electrons, positrons and of
the radio emission of the Galaxy. For the time we reproduce all relevant data
sets between 1 GeV and 1 TeV including the recent AMS-02 positron fraction
results.
  We show that below few GeV cosmic ray and radio data require that electron
primary spectrum to be drastically suppressed and the propagated spectrum be
dominated by secondary particles. Above 10 GeV an electron + positron
extra-component with a hard spectrum is required. The positron spectrum
measured below few GeV is consistently reproduced only within low
reacceleration models. We also constrain the scale-height of the cosmic-ray
distribution showing that a thin halo ($z_t \lsim 2 \kpc$) is excluded.


title: The sub-classes of ultraluminous X-ray sources

abstract:
  Ultraluminous X-ray sources (ULXs) were an enigma since their discovery. ASCA
showed that they are accreting black holes (BHs) with unknown mass, while
Chandra & XMM data shows that the many of the lower luminosity ULXs can be
explained by extreme accretion onto stellar remnant BHs. The discovery of
hyperluminous X-ray sources has led to specu- lation that we may, once again,
have found the elusive intermediate mass black holes, yet in the last year, a
third sub-class of extreme ULXs has emerged, with their nature, as yet, un-
known. Here we define and discuss the sub-classes of these fascinating systems,
exploring possible explanations for their nature, and indicating possible
future steps in their analysis.


title:
Covariant Differential Identities and Conservation Laws in
  Metric-Torsion Theories of Gravitation. I. General Consideration

abstract:
  Arbitrary diffeomorphically invariant metric-torsion theories of gravity are
considered. It is assumed that Lagrangians of such theories contain derivatives
of field variables (tensor densities of arbitrary ranks and weights) up to a
second order only. The generalized Klein-Noether methods for constructing
manifestly covariant identities and conserved quantities are developed.
Manifestly covariant expressions are constructed without including auxiliary
structures like a background metric. In the Riemann-Cartan space, the following
\emph{manifestly generally covariant results} are presented: (a) The complete
generalized system of differential identities (the Klein-Noether identities) is
obtained. (b) The generalized currents of three types depending on an arbitrary
vector field displacements are constructed: they are the canonical Noether
current, symmetrized Belinfante current and identically conserved
Hilbert-Bergmann current. In particular, it is stated that the symmetrized
Belinfante current does not depend on divergences in the Lagrangian. (c) The
generalized boundary Klein theorem (third Noether theorem) is proved. (d) The
construction of the generalized superpotential is presented in details, and
questions related to its ambiguities are analyzed.


title:
Gamma Ray Burst and star formation rates: The physical origin for the
  redshift evolution of their ratio

abstract:
  Gamma Ray Bursts (GRBs) and galaxies at high redshift represent complementary
probes of the star formation history of the Universe. In fact, both the GRB
rate and the galaxy luminosity density are connected to the underlying star
formation. Here, we combine a star formation model for the evolution of the
galaxy luminosity function from z=0 to z=10 with a metallicity-dependent
efficiency for GRB formation to simultaneously predict the comoving GRB rate.
Our model sheds light on the physical origin of the empirical relation often
assumed between GRB rate and luminosity density-derived star formation rate:
Rgrb(z) = \epsilon(z)*SFR_{obs}(z), with \epsilon(z) (1+z)^{1.2}. At z<4,
\epsilon(z) is dominated by the effects of metallicity evolution in the GRB
efficiency. Our best-fitting model only requires a moderate preference for
low-metallicity, that is a GRB rate per unit stellar mass about four times
higher for log(Z/Zsun)<-3 compared to log(Z/Zsun)>0. Models with total
suppression of GRB formation at log(Z/Zsun)>0 are disfavored. At z>4, most of
the star formation happens in low-metallicity hosts with nearly saturated
efficiency of GRB production per unit stellar mass. However at the same epoch,
galaxy surveys miss an increasing fraction of the predicted luminosity density
because of flux limits, driving an accelerated evolution of \epsilon(z)
compared to the empirical power-law fit from lower z. Our findings are
consistent with the non-detections of GRB hosts in ultradeep imaging at z>5,
and point toward current galaxy surveys at z>8 only observing the top 15-20 %
of the total luminosity density.


title:
Preliminary Investigation of a Waveform Analysis with the WASA and the
  ACQIRIS Readout Electronics

abstract:
  The Group for the development of neutron and gamma detectors in the Central
Institute of Engineering, Electronics and Analytics (ZEA-2) at
Forschungszentrum J\"ulich (FZJ) is developing a fast Anger Camera prototype
for improving the rejection of the gamma contamination during the detection of
neutrons. The prototype is based on a scintillating plate for neutron capture
and on the subsequent generation of scintillating light collected by a matrix
of 4x4 vacuum Photomultipliers R268 by Hamamatsu. According to the impinging
point position of the incoming neutrons the light is collected by different
PMTs, and via dedicated algorithms the x and y coordinates can be calculated.
In this note the WASA and ACQIRIS readout electronics are compared while
performing a waveform analysis of the signals generated by using both an
analogue pulse generator and an LED+PMT system. Different options of
pre-amplifiers and amplifiers are considered, and the results are here
presented and commented. At this stage of the prototype development,
systematical studies were not performed while the scope of this work was only
to validate the principle of operations by using both readout systems.


title:
The SONYC survey: Towards a complete census of brown dwarfs in star
  forming regions

abstract:
  SONYC, short for "Substellar Objects in Nearby Young Clusters", is a survey
program to provide a census of the substellar population in nearby star forming
regions. We have conducted deep optical and near-infrared photometry in five
young regions (NGC1333, rho Ophiuchi, Chamaeleon-I, Upper Sco, and Lupus-3),
combined with proper motions, and followed by extensive spectroscopic campaigns
with Subaru and VLT, in which we have obtained more than 700 spectra of
candidate low-mass objects. We have identified and characterized more than 60
new substellar objects, among them a handful of objects with masses close to,
or below the Deuterium burning limit. Through SONYC and surveys by other
groups, the substellar IMF is now well characterized down to ~ 5 - 10 MJup, and
we find that the ratio of the number of stars with respect to brown dwarfs lies
between 2 and 6. A comprehensive survey of NGC 1333 reveals that, down to
~5MJup, free-floating objects with planetary masses are 20-50 times less
numerous than stars, i.e. their total contribution to the mass budget of the
clusters can be neglected.


title: New Indivisible Planetary Science Paradigm

abstract:
  I present here a new, indivisible planetary science paradigm, a wholly
self-consistent vision of the nature of matter in the Solar System, and
dynamics and energy sources of planets. Massive-core planets formed by
condensing and raining-out from within giant gaseous protoplanets at high
pressures and high temperatures. Earth's complete condensation included a 300
Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66%
of Earth's present diameter. T-Tauri eruptions stripped the gases away from the
inner planets and stripped a portion of Mercury's incompletely condensed
protoplanet, and transported it to the region between Mars and Jupiter where it
fused with in-falling oxidized condensate from the outer regions of the Solar
System and formed the parent matter of ordinary chondrite meteorites, the
main-Belt asteroids, and veneer for the inner planets, especially Mars. In
response to decompression-driven planetary volume increases, cracks form to
increase surface area and mountain ranges characterized by folding form to
accommodate changes in curvature. The differences between the inner planets are
primarily the consequence of different degrees of protoplanetary compression.
The internal composition of Mercury is calculated by analogy with the Earth.
The rationale is provided for Mars potentially having a greater subsurface
water reservoir capacity than before realized.


title: Universality at the Edge for Unitary Matrix Models

abstract:
  Using the results on the $1/n$-expansion of the Verblunsky coefficients for a
class of polynomials orthogonal on the unit circle with $n$ varying weight, we
prove that the local eigenvalue statistic for unitary matrix models is
independent of the form of the potential, determining the matrix model. Our
proof is applicable to the case of four times differentiable potentials and of
supports, consisting of one interval.


title: Two-Pulse Ionization Injection into Quasi-Linear Laser Wakefields

abstract:
  We describe a scheme for controlling electron injection into the quasi-linear
wakefield driven by a guided drive pulse via ionization of a dopant species by
a collinear injection laser pulse with a short Rayleigh range. The scheme is
analyzed by particle in cell simulations which show controlled injection and
acceleration of electrons to an energy of 370 MeV, a relative energy spread of
2%, and a normalized transverse emittance of 3.0 {\mu}m.
  This is an arXiv version of the original APS paper. It should be cited as N.
Bourgeois, J. Cowley, and S. M. Hooker, Phys. Rev. Lett. 111, 155004 (2013).
APS link here: http://link.aps.org/doi/10.1103/PhysRevLett.111.155004


title:
Optimized controlled Z gates for two superconducting qubits coupled
  through a resonator

abstract:
  Superconducting qubits are a promising candidate for building a quantum
computer. A continued challenge for fast yet accurate gates to minimize the
effects of decoherence. Here we apply numerical methods to design fast
entangling gates, specifically the controlled Z, in an architecture where two
qubits are coupled via a resonator. We find that the gates can be sped up by a
factor of two and reach any target fidelity. We also discuss how systematic
errors arising from experimental conditions affect the pulses and how to remedy
them, providing a strategy for the experimental implementation of our results.
We discuss the shape of the pulses, their spectrum and symmetry.


title: q-Bernoulli polynomials and q-umbral calculus

abstract:
  In this paper, we investigate some properties of q-Bernoulli polynomi- als
arising from q-umbral calculus. Finally, we derive some interesting identities
of q-Bernoulli polynomials from our investigation.


title: Scanning for oriented configuration spaces

abstract:
  In [Pal13] (arXiv:1106.4540) the second author proved that the sequence of
"oriented" configuration spaces on an open connected manifold exhibits
homological stability as the number of particles goes to infinity. To
complement that result we identify the corresponding limiting space, up to
homology equivalence, as a certain explicit double cover of a section space.
Along the way we also prove that the scanning map of McDuff in [McD75] for
unordered configuration spaces is acyclic in the limit.


title:
Development of sensitive long-wave infrared detector arrays for
  passively cooled space missions

abstract:
  The near-earth object camera (NEOCam) is a proposed infrared space mission
designed to discover and characterize most of the potentially hazardous
asteroids larger than 140 m in diameter that orbit near the Earth. NASA has
funded technology development for NEOCam, including the development of long
wavelength infrared detector arrays that will have excellent zodiacal
background emission-limited performance at passively cooled focal plane
temperatures. Teledyne Imaging Sensors has developed and delivered for test at
the University of Rochester the first set of approximately 10 micron cutoff,
1024 x 1024 pixel HgCdTe detector arrays. Measurements of these arrays show the
development to be extremely promising: noise, dark current, quantum efficiency,
and well depth goals have been met by this technology at focal plane
temperatures of 35 to 40 K, readily attainable with passive cooling. The next
set of arrays to be developed will address changes suggested by the first set
of deliverables.


title:
Quantum phases of incommensurate optical lattices due to cavity
  backaction

abstract:
  Ultracold bosonic atoms are confined by an optical lattice inside an optical
resonator and interact with a cavity mode, whose wave length is incommensurate
with the spatial periodicity of the confining potential. We predict that the
intracavity photon number can be significantly different from zero when the
atoms are driven by a transverse laser whose intensity exceeds a threshold
value and whose frequency is suitably detuned from the cavity and the atomic
transition frequency. In this parameter regime the atoms form clusters in which
they emit in phase into the cavity. The clusters are phase locked, thereby
maximizing the intracavity photon number. These predictions are based on a
Bose-Hubbard model, whose derivation is here reported in detail. The
Bose-Hubbard Hamiltonian has coefficients which are due to the cavity field and
depend on the atomic density at all lattice sites. The corresponding phase
diagram is evaluated using Quantum Monte Carlo simulations in one-dimension and
mean-field calculations in two dimensions. Where the intracavity photon number
is large, the ground state of the atomic gas lacks superfluidity and possesses
finite compressibility, typical of a Bose-glass.


title: Concavity properties of extensions of the parallel volume

abstract:
  In this paper we establish concavity properties of two extensions of the
classical notion of the outer parallel volume. On the one hand, we replace the
Lebesgue measure by more general measures. On the other hand, we consider a
functional version of the outer parallel sets.


title:
Nonstandard techniques and nowhere differentiable functions I: A dense
  family of generalized blancmange functions

abstract:
  We will give an elementary nonstandard proof that the family of generalized
blancmange functions are nowhere differentiable. The proof follows from the
intuitive characterization of differentiability at a point as almost $\delta$
affine along with the transfer of the functional equations these functions
satisfy. We also give elementary nonstandard proofs of the uniform density of
these functions among continuous functions. Finally, we discuss work done with
the Python programming language in displaying these functions.


title: Some identities of q-Euler polynomials arising from q-umbral calculus

abstract:
  Recently, Araci-Acikgoz-Sen derived some interesting identities on weighted
q-Euler polynomials and higher-order q-Euler polynomials from the applications
of umbral calculus (See [1]). In this paper, we develop the new method of
q-umbral calculus due to Roman and we study new q-extension of Euler numbers
and polynomials which are derived from q-umbral calculus. Finally, we give some
interesting identities on our q-Euler polynomials related to the q-Bernoulli
numbers and polynomials of Hegazi and Mansour.


title: Method of Lines Transpose: A Fast Implicit Wave Propagator

abstract:
  As a follow up to \cite{Causley2013}, we provide a detailed description of
the numerical implementation of an O(N), A-stable, second order accurate
solution of the wave equation, constructed from semi-discrete boundary value
problems. We improve on the previous algorithm by replacing the Lax-type
correction used in \cite{Causley2013}, which was necessary for convergence when
$\Delta t < \Delta x/c$, with a more accurate spatial quadrature, which we
prove is convergent.
  We also demonstrate that the resulting solver remains fast even in the case
of unstructured meshes, can incorporate domain decomposition, and allows for
the implementation of Dirichlet, Neumann, periodic and outflow boundary
conditions.
  Building upon results for the 1d formulation, we utilize alternate direction
implicit (ADI) splitting to achieve a fast O(N) solver in higher spatial
dimensions. Our solver is built upon line objects and, combined with the
flexibility of the integral solver, allows us to solve problems on arbitrary
spatial domains, by embedding the boundary in a regular Cartesian mesh. Our
solver is designed to couple with particle codes, where scale separation is an
issue. We therefore demonstrate the ability of our solver to take time steps
well beyond that of the Courant-Friedrichs-Lewy (CFL) stability limit of
explicit codes.


title: Charge fluctuations in nano-scale capacitors

abstract:
  The fluctuations of the charge on an electrode contain information on the
microscopic correlations within the adjacent fluid and their effect on the
electronic properties of the interface. We investigate these fluctuations using
molecular dynamics simulations in a constant-potential ensemble with histogram
reweighting techniques. This approach offers in particular an efficient,
accurate and physically insightful route to the differential capacitance that
is broadly applicable. We demonstrate these methods with three different
capacitors: pure water between platinum electrodes, and a pure as well as a
solvent-based organic electrolyte each between graphite electrodes. The total
charge distributions with the pure solvent and solvent-based electrolytes are
remarkably Gaussian, while in the pure ionic liquid the total charge
distribution displays distinct non-Gaussian features, suggesting significant
potential-driven changes in the organization of the interfacial fluid.


title: Prospective applications of optical quantum memories

abstract:
  An optical quantum memory can be broadly defined as a system capable of
storing a useful quantum state through interaction with light at optical
frequencies. During the last decade, intense research was devoted to their
development, mostly with the aim of fulfilling the requirements of their first
two applications, namely quantum repeaters and linear-optical quantum
computation. A better understanding of those requirements then motivated
several different experimental approaches. Along the way, other exciting
applications emerged, such as as quantum metrology, single-photon detection,
tests of the foundations of quantum physics, device-independent quantum
information processing and nonlinear processing of quantum information. Here we
review several prospective applications of optical quantum memories with a
focus on recent experimental achievements pertaining to these applications.
This review highlights that optical quantum memories have become essential for
the development of optical quantum information processing.


title:
The performance of the CMS muon detector in proton-proton collisions at
  sqrt(s) = 7 TeV at the LHC

abstract:
  The performance of all subsystems of the CMS muon detector has been studied
by using a sample of proton--proton collision data at sqrt(s) = 7 TeV collected
at the LHC in 2010 that corresponds to an integrated luminosity of
approximately 40 inverse picobarns. The measured distributions of the major
operational parameters of the drift tube (DT), cathode strip chamber (CSC), and
resistive plate chamber (RPC) systems met the design specifications. The
spatial resolution per chamber was 80-120 micrometers in the DTs, 40-150
micrometers in the CSCs, and 0.8-1.2 centimeters in the RPCs. The time
resolution achievable was 3 ns or better per chamber for all 3 systems. The
efficiency for reconstructing hits and track segments originating from muons
traversing the muon chambers was in the range 95-98%. The CSC and DT systems
provided muon track segments for the CMS trigger with over 96% efficiency, and
identified the correct triggering bunch crossing in over 99.5% of such events.
The measured performance is well reproduced by Monte Carlo simulation of the
muon system down to the level of individual channel response. The results
confirm the high efficiency of the muon system, the robustness of the design
against hardware failures, and its effectiveness in the discrimination of
backgrounds.


title: Wigner crystallization in the quantum 1D jellium at all densities

abstract:
  The jellium is a model, introduced by Wigner (1934), for a gas of electrons
moving in a uniform neutralizing background of positive charge. Wigner
suggested that the repulsion between electrons might lead to a broken
translational symmetry. For classical one-dimensional systems this fact was
proven by Kunz (1974), while in the quantum setting, Brascamp and Lieb (1975)
proved translation symmetry breaking at low densities. Here, we prove
translation symmetry breaking for the quantum one-dimensional jellium at all
densities.

categories: math-ph cond-mat.stat-mech math.MP math.PR


title:
Characterization and performances of a monitoring ionization chamber
  dedicated to IBA-universal irradiation head for Pencil Beam Scanning

abstract:
  Every radiotherapy center has to be equipped with real-time beam monitoring
devices. In 2008, the medical application group from the Laboratory of
Corpuscular Physics (LPC Caen) developed an Ionization Chamber in collaboration
with the company IBA (Ion Beam Applications). This monitoring device called
IC2/3 was developed to be used in IBAs universal irradiation head for Pencil
Beam Scanning (PBS). The objectives presented in this article are to
characterize the IC2/3 monitor in the energy and ux ranges used in
protontherapy. The equipment has been tested with an IBAs cyclotronable to
deliver proton beams from 70 to 230 MeV. This beam monitoring device has been
validated and is now installed at the Westdeutsches Protonentherapiezentrum
Essen protontherapy center (WPE, Germany). The results obtained in both terms
of spatial resolution and dose measurements are at least equal to the initials
speci cations needed for PBS purposes. The detector measures the dose with a
relative precision better than 1% in the range 0.5 Gy/min to 8 Gy/min while the
spatial resolution is higher than 250 m. The technology has been patented and
ve IC2/3 chambers were delivered to IBA. Nowadays, IBA produces the IC2/3 beam
monitoring device as part of its Proteus 235 product


title: Moriond QCD 2013 Experimental Summary

abstract:
  The article presents experimental highlights of Moriond 2013 QCD conference.
This was fantastic conference and the first Moriond QCD since the discovery of
the Higgs boson. Many new results about its properties have been presented at
the conference with Higgs-like particle becoming a Higgs as it properties match
expected for the Higgs boson pretty well. There were many new results presented
in all experimental areas including QCD, elecroweak, studies of the top, bottom
and charm quarks, searches for physics beyond Standard Model as well as studies
of the heavy ion collisions. 56 experimental talks have been presented at the
conference and it is impossible to cover each result in the summary, so
highlights are limited to what I was able to present in my summary talk
presented on March 16 2013. The proceedings of the conference cover in depth
all talks presented and I urge you to get familiar with all of them.
Theoretical Summary of the conference was given by Michelangelo Mangano, so
theory talks are not covered in the article.


title: Exact Support Recovery for Sparse Spikes Deconvolution

abstract:
  This paper studies sparse spikes deconvolution over the space of measures. We
focus our attention to the recovery properties of the support of the measure,
i.e. the location of the Dirac masses. For non-degenerate sums of Diracs, we
show that, when the signal-to-noise ratio is large enough, total variation
regularization (which is the natural extension of the L1 norm of vectors to the
setting of measures) recovers the exact same number of Diracs. We also show
that both the locations and the heights of these Diracs converge toward those
of the input measure when the noise drops to zero. The exact speed of
convergence is governed by a specific dual certificate, which can be computed
by solving a linear system. We draw connections between the support of the
recovered measure on a continuous domain and on a discretized grid. We show
that when the signal-to-noise level is large enough, the solution of the
discretized problem is supported on pairs of Diracs which are neighbors of the
Diracs of the input measure. This gives a precise description of the
convergence of the solution of the discretized problem toward the solution of
the continuous grid-free problem, as the grid size tends to zero.


title: Segre embeddings, Hilbert series and Newcomb's problem

abstract:
  Monomial ideals and toric rings are closely related. By consider a Grobner
basis we can always associated to any ideal $I$ in a polynomial ring a monomial
ideal ${\rm in}_\prec I$, in some special situations the monomial ideal ${\rm
in}_\prec I$ is square free. On the other hand given any monomial ideal $I$ of
a polynomial ring $S$, we can define the toric $K[I]\subset S$. In this paper
we will study toric rings defined by Segre embeddings, we will prove that their
$h-$ vectors coincides with the so called Simon Newcomb number's in
probabilities and combinatorics. We solve the original question of Simon
Newcomb by given a formula for the Simon Newcomb's numbers involving only
positive integer numbers.


title:
Stochastic Background of Gravitational Waves from Fermions -- Theory and
  Applications

abstract:
  Out-of-equilibrium fermions can be created in the early Universe by
non-perturbative parametric effects, both at preheating or during the thermal
era. An anisotropic stress is developed in the fermion distribution, acting as
a source of a stochastic background of gravitational waves (GW). We derive a
general formalism to calculate the spectrum of GW produced by an ensemble of
fermions, which we apply to a variety of scenarios after inflation. We discuss
in detail the regularization of the source, i.e. of the unequal-time-correlator
of the fermions' transverse-traceless anisotropic stress. We discuss how the GW
spectrum builds up in time and present a simple parametrization of its final
amplitude and peak frequency. We find that fermions may generate a GW
background with a significant amplitude at very high frequencies, similarly to
the case of preheating with scalar fields. A detection of this GW background
would shed light about the physics of the very early Universe, but new
technology at high frequencies is required, beyond the range accessible to
currently planned detectors.


title:
New Developments in Time-Independent Quantum-Mechanical Perturbation
  Theory

abstract:
  This report discusses two new ideas for using perturbation methods to solve
the time-independent Schr\"odinger equation. The first concept begins with
rewriting the perturbation equations in a form that is closely related to
matrix diagonalization methods. That allows a simple, compact derivation of the
standard (Rayleigh-Schr\"odinger) equations. But it also leads to a new
iterative solution method that is not based on the usual power series
expansion. The iterative method can also be used when the unperturbed system is
two-fold degenerate. The second concept is quite different from the first but
compatible with it. It is based on the fact that one can replace the true
Hamiltonian with a synthetic Hamiltonian having the same eigenvalues. This
approach allows one to cancel part of the perturbation and to reduce the size
of the off-diagonal matrix elements, giving better convergence of the series.
These methods are illustrated by application to three perturbed harmonic
oscillator problems--a 1-D oscillator with a linear perturbation, a 1-D
oscillator with a quartic perturbation, and a perturbed 2-D oscillator, which
involves degenerate states. The iterative method and the synthetic Hamiltonian
method are shown to give significantly better results than the standard method.


title: Calculation of Release Adiabats and Shock Impedance Matching

abstract:
  In the analysis of impedance-match experiments, the release adiabat of the
standard material is often approximated by reflecting the Hugoniot in the
pressure-particle velocity (P-UP) plane. In cases where it has been tested
experimentally, this reflected shock approximation (RSA) has been found to be
fairly accurate at pressures as high as 100 GPa. The success of the RSA is
usually attributed to the lack of thermal effects, i.e., that the Hugoniot and
release adiabat are nearly identical in the pressure-density (P-rho) plane.
This report demonstrates that this explanation is not correct. The success of
the RSA does not arise from the absence of thermal effects--it arises because
of thermal effects. When the Hugoniot and adiabat are identical in the P-rho
plane, the adiabat lies below the reflected Hugoniot when mapped into the P-UP
plane. Material strength effects also cause the exact adiabat to lie below the
RSA. A thermal offset between the Hugoniot and the adiabat compensates for
these two effects, so that the RSA turns out to give good results for many
materials, even at high pressures. However, this fortuitous cancellation of
errors does not occur in all cases. This report shows that the RSA is not
accurate for two "soft" materials, Teflon and PMMA, and for a high-strength
material, tungsten. The issues discussed here apply to use of the RSA at low
pressures, not to very high pressures, where it is already well-known to be
inaccurate.


title: Hadron Colliders and Hadron Collider Physics Symposium

abstract:
  This article summarizes main developments of the hadron colliders and physics
results obtained since their inception around forty years ago. The increase in
the collision energy of over two orders of magnitude and even larger increases
in luminosity provided experiments with unique data samples. Developments of
full acceptance detectors, particle identification and analysis methods
provided fundamental discoveries and ultra-precise measurements which
culminated in the completion and in depth verification of the Standard Model.
Hadron Collider Physics symposium provided opportunities for those working at
hadron colliders to share results of their research since 1979 and helped
greatly to develop the field of particle physics.


title: Some remarks about the old problem of recombination

abstract:
  Context: In the seminal works of Zeldovich et al. (1968) and Peebles (1968),
a procedure was outlined to obtain the equation of evolution of the hydrogen
fraction without an explicit use of the radiative transfer equation. This
procedure is based, explicitly or implicitly, on the concept of escape
probability and, using the Sobolev approximation for this problem Sobolev
(1960), has extensively been used since then in developing refined
approximations.
  Aims: To derive in a simple, rigorous and general manner the above mentioned
procedure and to obtain exact analytical expressions for the spectral density
of radiation generated at one photon and two photon recombination transitions.
These expressions are used to estimate the implications of several interesting
effects.
  Methods: Some slight re-elaborations of basic principles of transport theory.
  Results: We have obtained the expressions searched for and used them in
several explicit computations. We have found that the relative change in the
electronic fraction due to the absorption by the two photon line, 1s->2s, of
photons that have escaped from the line 2p-> 1s is 0.67%, that is a result 12%
higher than the previous ones obtained using some approximations (Kholupenko &
Ivanchik 2006; Hirata 2008). The photons generated by the transition 2s->1s and
later absorbed by the same transition (in combination with a photon more
energetic than its original partner) imply a 0.05% maximum variation of the
electronic fraction. This problem has not been treated previously analytically,
although a numerical estimate have been recently carried out in Chluba & Thomas
2011.


title: The Linear US-uP Relation in Shock-Wave Physics

abstract:
  A linear relation between shock velocity US and particle velocity UP is often
regarded as the "typical" or "standard" material response in the shock-wave
literature. It has even been proposed that this linearity follows from some
kind of universal equation of state (EOS) principle. This report presents a
theoretical analysis of this issue and a survey of the Hugoniot data for all
the elements. It demonstrates that linearity follows from the fact that US-UP
plots are rather insensitive to material properties, not from any universal
EOS. The effects of pressure and material properties on the shock response are
more easily seen and analyzed by plotting UF = US - UP as a function of UP. The
data survey shows that linear behavior is only observed in 20% of all the
elements and is not at all universal.


title:
What wormhole is traversable?: A case of a wormhole supported by a
  spherical thin shell

abstract:
  We analytically explore the effect of falling matter on a spherically
symmetric wormhole supported by a spherical shell composed of exotic matter
located at its throat. The falling matter is assumed to be also a thin
spherical shell concentric with the shell supporting the wormhole, and its
self-gravity is completely taken into account. We treat these spherical thin
shells by Israel's formalism of metric junction. When the falling spherical
shell goes through the wormhole, it necessarily collides with the shell
supporting the wormhole. To treat this collision, we assume the interaction
between these shells is only gravity. We show the conditions on the parameters
that characterize this model in which the wormhole persists after the spherical
shell goes through it.


title: The low energy limit of the AdS(3) x S(3) x M(4) spinning string

abstract:
  We derive the low-energy effective action for the spinning (GKP) string in
AdS(3) x S(3) x M(4) where M(4) = S(3) x S(1) or T(4). In the first case the
action consists of two O(4) non-linear sigma models which are coupled through
their interaction with four massless Majorana fermions (plus one free decoupled
scalar). While in the second case it consists of one O(4) sigma model coupled
to four Majorana fermions together with four free scalars from the T(4). We
show that these models are classically integrable by constructing their Lax
connections.


title:
The waiting time for a second mutation: an alternative to the Moran
  model

abstract:
  The appearance of cancer in a tissue is thought to be the result of two or
more successive mutations. We propose a stochastic model that allows for an
exact computation of the distribution of the waiting time for a second
mutation. This models the time of appearance of the first cancerous cell in a
tissue. Our model is an alternative to the Moran model with mutations.


abstract:
  As computer systems become more pervasive and complex, security is
increasingly important. Secure Transmission refers to the transfer of data such
as confidential or proprietary information over a secure channel. Many secure
transmission methods require a type of encryption. Secure transmissions are put
in place to prevent attacks such as ARP spoofing and general data loss. Hence,
in order to provide a better security mechanism, in this paper we propose
Enhanced Tiny Encryption Algorithm with Embedding (ETEA), a data hiding
technique called steganography along with the technique of encryption
(Cryptography). The advantage of ETEA is that it incorporates cryptography and
steganography. The advantage proposed algorithm is that it hides the messages.


title:
Direct evidence for a Coulombic phase in monopole-suppressed SU(2)
  lattice gauge theory

abstract:
  Further evidence is presented for the existence of a non-confining phase at
weak coupling in SU(2) lattice gauge theory. Using Monte Carlo simulations with
the standard Wilson action, gauge-invariant SO(3)-Z2 monopoles, which are
strong-coupling lattice artifacts, have been seen to undergo a percolation
transition exactly at the phase transition previously seen using Coulomb-gauge
methods, with an infinite lattice critical point near $\beta = 3.2$. The theory
with both Z2 vortices and monopoles and SO(3)-Z2 monopoles eliminated is
simulated in the strong coupling ($\beta = 0$) limit on lattices up to $60^4$.
Here, as in the high-$\beta$ phase of the Wilson action theory, finite size
scaling shows it spontaneously breaks the remnant symmetry left over after
Coulomb gauge fixing. Such a symmetry breaking precludes the potential from
having a linear term. The monopole restriction appears to prevent the
transition to a confining phase at any $\beta$. Direct measurement of the
instantaneous Coulomb potential shows a Coulombic form with moderately running
coupling possibly approaching an infrared fixed point of $\alpha \sim 1.4$. The
Coulomb potential is measured to 50 lattice spacings and 2 fm. A short-distance
fit to the 2-loop perturbative potential is used to set the scale. High
precision at such long distances is made possible through the use of open
boundary conditions, which was previously found to cut random and systematic
errors of the Coulomb gauge fixing procedure dramatically. The Coulomb
potential agrees with the gauge-invariant interquark potential measured with
smeared Wilson loops on periodic lattices as far as the latter can be
practically measured with similar statistics data.


title:
Stochastic Variational Method as Quantization Scheme I: Field
  Quantization of Complex Klein-Gordan Equation

abstract:
  Stochastic Variational Method (SVM) is the generalization of the variation
method to the case with stochastic variables. In the series of papers, we
investigate the applicability of SVM as an alternative field quantization
scheme. Here, we discuss the complex Klein-Gordon equation. In this scheme, the
Euler-Lagrangian equation for the stochastic fields leads to the functional
Schroedinger equation, which in turn can be interpreted as the ideal fluid
equation in the functional space. We show that the Fock state vector is given
by the stationary solution of these differential equations and various results
in the usual canonical quantization can be reproduced, including the effect of
anti-particles. The present formulation is a quantization scheme based on
commutable variables, so that there appears no ambiguity associated with the
ordering of operators, for example, in the definition of Noether charges.

categories: hep-th cond-mat.stat-mech gr-qc math-ph math.MP quant-ph


title:
Monte Carlo adaptive resolution simulation of multicomponent molecular
  liquids

abstract:
  Complex soft matter systems can be efficiently studied with the help of
adaptive resolution simulation methods, concurrently employing two levels of
resolution in different regions of the simulation domain. The non-matching
properties of high- and low-resolution models, however, lead to thermodynamic
imbalances between the system's subdomains. Such inhomogeneities can be healed
by appropriate compensation forces, whose calculation requires nontrivial
iterative procedures. In this work we employ the recently developed Hamiltonian
Adaptive Resolution Simulation method to perform Monte Carlo simulations of a
binary mixture, and propose an efficient scheme, based on Kirkwood
Thermodynamic Integration, to regulate the thermodynamic balance of
multi-component systems.


title: Optimal Tx-BF for MIMO SC-FDE Systems

abstract:
  Transmit beamforming (Tx-BF) for multiple-input multiple-output (MIMO)
channels is an effective means to improve system performance. In
frequency-selective channels, Tx-BF can be implemented in combination with
single-carrier frequency-domain equalization (SC-FDE) to combat inter-symbol
interference. In this paper, we consider the optimal design of the Tx-BF matrix
for a MIMO SC-FDE system employing a linear minimum mean square error (MSE)
receiver. We formulate the Tx-BF optimization problem as the minimization of a
general function of the stream MSEs, subject to a transmit power constraint.
The optimal structure of the Tx-BF matrix is obtained in closed form and an
efficient algorithm is proposed for computing the optimal power allocation. Our
simulation results validate the excellent performance of the proposed scheme in
terms of uncoded bit-error rate and achievable bit rate.


title:
Off-shell extrapolation of Regge-model NN scattering amplitudes
  describing final state interactions in $^2H(e,e'p)$

abstract:
  In this work, an off-shell extrapolation is proposed for the Regge-model $NN$
amplitudes of \cite{FVO_Reggemodel}. A prescription for extrapolating these
amplitudes for one nucleon off-shell in the initial state are given.
Application of these amplitudes to calculations of deuteron
electrodisintegration are presented and compared to the limited available
precision data in the kinematical region covered by the Regge model.


title:
Set theory and topology. An introduction to the foundations of analysis.
  Part II: Topology - Fundamental notions

abstract:
  We provide a formal introduction into the classic theorems of general
topology and its axiomatic foundations in set theory. In this second part we
introduce the fundamental concepts of topological spaces, convergence, and
continuity, as well as their applications to real numbers. Various methods to
construct topological spaces are presented.


title: Numerically Investigating the Emergent Cyclic Inflation Scenario

abstract:
  We provide a comprehensive numerical study of the Emergent Cyclic Inflation
scenario. This is a scenario where instead of traditional monotonic slow roll
inflation, the universe expands over numerous short asymmetric cycles due to
the production of entropy via interactions among different species. This is one
of the very few scenarios of inflation which provides a nonsingular
geodesically complete space-time and does not require any "reheating"
mechanism.


title:
Objective Bayesian hypothesis testing in binomial regression models with
  integral prior distributions

abstract:
  In this work we apply the methodology of integral priors to handle Bayesian
model selection in binomial regression models with a general link function.
These models are very often used to investigate associations and risks in
epidemiological studies where one goal is to exhibit whether or not an exposure
is a risk factor for developing a certain disease; the purpose of the current
paper is to test the effect of specific exposure factors. We formulate the
problem as a Bayesian model selection case and solve it using objective Bayes
factors. To construct the reference prior distributions on the regression
coefficients of the binomial regression models, we rely on the methodology of
integral priors that is nearly automatic as it only requires the specification
of estimation reference priors and it does not depend on tuning parameters or
on hyperparameters within these priors.


title:
Power indices of influence games and new centrality measures for social
  networks

abstract:
  In social network analysis, there is a common perception that influence is
relevant to determine the global behavior of the society and thus it can be
used to enforce cooperation by targeting an adequate initial set of individuals
or to analyze global choice processes. Here we propose centrality measures that
can be used to analyze the relevance of the actors in process related to spread
of influence. In [39] it was considered a multiagent system in which the agents
are eager to perform a collective task depending on the perception of the
willingness to perform the task of other individuals. The setting is modeled
using a notion of simple games called influence games. Those games are defined
on graphs were the nodes are labeled by their influence threshold and the
spread of influence between its nodes is used to determine whether a coalition
is winning or not. Influence games provide tools to measure the importance of
the actors of a social network by means of classic power indices and provide a
framework to consider new centrality criteria. In this paper we consider two of
the most classical power indices, i.e., Banzhaf and Shapley-Shubik indices, as
centrality measures for social networks in influence games. Although there is
some work related to specific scenarios of game-theoretic networks, here we use
such indices as centrality measures in any social network where the spread of
influence phenomenon can be applied. Further, we define new centrality measures
such as satisfaction and effort that, as far as we know, have not been
considered so far. We also perform a comparison of the proposed measures with
other three classic centrality measures, degree, closeness and betweenness,
considering three social networks. We show that in some cases our measurements
provide centrality hierarchies similar to those of other measures, while in
other cases provide different hierarchies.


title:
Cone Monotonicity: Structure Theorem, Properties, and Comparisons to
  Other Notions of Monotonicity

abstract:
  In search of a meaningful 2-dimensional analog to mono- tonicity, we
introduce two new definitions and give examples of and dis- cuss the
relationship between these definitions and others that we found in the
literature. Note: After we published the article in Abstract and Applied
Analysis and after we searched multiple times for previous work, we discovered
that Clarke at al. had introduced the definition of cone monotonicity and given
a characterization. See the addendum at the end of this paper for full
reference information.


title: Higgs xi-inflation for the 125-126 GeV Higgs: a two-loop analysis

abstract:
  A non-minimal coupling xi of the Standard Model Higgs field to gravity can
give rise to inflation, but large xi is required and thus leads to a violation
of perturbative unitarity at Mp/xi, which is well below the inflationary scale
Mp/sqrt(xi). We re-examine this claim for a Higgs mass in the range 125-126 GeV
for which lambda_eff(mu) runs to very small values near the Planck scale and
can significantly reduce the value of xi required for inflation. Using the
two-loop renormalization group equations and effective potential for Higgs
xi-inflation, we find that familiar inflationary solutions can have a
non-minimal coupling as small as xi ~ 400 without the potential developing a
second minimum. We also find a new observationally allowed region of Higgs
xi-inflation with xi ~ 90 and distinct inflationary predictions, including an
observable level of the tensor-to-scalar ratio r.


title: Asymmetric Sky from the Long Mode Modulations

abstract:
  The observed dipole asymmetry in Cosmic Microwave Background radiation may
have originated from the modulations of super-horizon long wavelength modes. In
this work we unveil different aspects of asymmetries generated from the long
wavelength mode modulations. We show that the same mechanism which leads to the
observed CMB power spectrum dipole asymmetry from the long mode modulations
also yields dipole asymmetry in (a): tensor perturbations power spectrum and
(b): the halo bias parameter. These are different phenomena relevant to
different cosmological histories but both share the same underlying mechanism
in generating asymmetries in the sky. We obtain the set of consistency
conditions relating the amplitude of dipole asymmetries generated on tensor
perturbations and halo bias parameter to the amplitude of dipole asymmetry
generated on CMB power spectrum. In addition, we show that this mechanism does
not produce dipole asymmetry in acceleration expansion in $\Lambda CDM$
universe because the super-horizon curvature perturbation is conserved in this
background.


title: The Recurrent Nova T CrB Did Not Erupt in 1842

abstract:
  The recurrent nova T CrB was one of the first well observed nova eruptions in
1866, and 80 years later it erupted again in 1946. Just after the 1866
eruption, Sir John Herschel reported to the Monthly Notices that he had seen
the same star in his naked-eye charting of the sky on 1842 June 9, implying
that there was a prior eruption 24 years earlier. Unfortunately, the chart in
the Monthly Notices was ambiguous and misleading, so it has long been unclear
whether T CrB did indeed have an eruption in 1842. To resolve this, I have
searched the various archives with Herschel material, and have found his
original correspondence. In one letter from 1866 to William Huggins, Herschel
enclosed his own copy of his original observations, and with this all the
ambiguities are resolved. It turns out that Herschel's indicated star was at
the same position as a steady background star (BD+25{\deg}3020, V=7.06, G8V)
and not that of T CrB, and Herschel regularly was seeing stars as faint as
V=7.5 mag because he was using an opera glass. With this, there is no evidence
for a T CrB eruption in 1842.


title:
Universal time-fluctuations in near-critical out-of-equilibrium quantum
  dynamics

abstract:
  Out of equilibrium quantum systems, on top of quantum fluctuations, display
complex temporal patterns. Such time fluctuations are generically exponentially
small in the system volume and can be therefore safely ignored in most of the
cases. However, if one consider small quench experiments, time fluctuations can
be greatly enhanced. We show that time fluctuations may become stronger than
other forms of equilibrium quantum fluctuations if the quench is performed
close to a critical point. For sufficiently relevant operators the full
distribution function of dynamically evolving observable expectation values,
becomes a universal function uniquely characterized by the critical exponents
and the boundary conditions. At regular points of the phase diagram and for non
sufficiently relevant operators the distribution becomes Gaussian. Our
predictions are confirmed by an explicit calculation on the quantum Ising
model.


title:
NoSOCS in SDSS III - The interplay between galaxy evolution and the
  dynamical state of galaxy clusters

abstract:
  We investigate relations between the color and luminosity distributions of
cluster galaxies and the evolutionary state of their host clusters. Our aim is
to explore some aspects of cluster galaxy evolution and the dynamical state of
clusters as two sides of the same process. We used 10,721 member galaxies of
183 clusters extracted from the Sloan Digital Sky Survey using a list of NoSOCS
and CIRS targets. First, we classified the clusters into two categories,
Gaussian and non-Gaussian, according to their velocity distribution
measurements, which we used as an indicator of their dynamical state. We then
used objective criteria to split up galaxies according to their luminosities,
colors, and photometric mean stellar age. This information was then used to
evaluate how galaxies evolve in their host clusters. Meaningful color
gradients, i.e., the fraction of red galaxies as a function of radius from the
center, are observed for both the Gaussian velocity distribution and the
non-Gaussian velocity distribution cluster subsamples, which suggests that
member galaxy colors change on a shorter timescale than the time needed for the
cluster to reach dynamical equilibrium. We also found that larger portions of
fainter red galaxies are found, on average, in smaller radii. The luminosity
function in Gaussian clusters has a brighter characteristic absolute magnitude
and a steeper faint-end slope than it does in the non-Gaussian velocity
distribution clusters. Our findings suggest that cluster galaxies experience
intense color evolution before virialization, while the formation of faint
galaxies through dynamical interactions probably takes place on a longer
timescale, possibly longer than the virialization time.


title:
Hybrid Density Functional Study of Structural and Electronic Properties
  of Functionalized \ce{Ti_{n+1}X_n} (X= C, N) monolayers

abstract:
  Density functional theory simulations with conventional (PBE) and hybrid
(HSE06) functionals were performed to investigate the structural and electronic
properties of MXene monolayers, \ce{Ti_{n+1}C_n} and \ce{Ti_{n+1}N_n} ($n$ =
1--9) with surfaces terminated by O, F, H, and OH groups. We find that PBE and
HSE06 give similar results. Without functional groups, MXenes have magnetically
ordered ground states. All the studied materials are metallic except for
\ce{Ti_{2}CO_{2}}, which we predict to be semiconducting. The calculated
density of states at the Fermi level of the thicker MXenes ($n$ $\geqslant$ 5)
is much higher than for thin MXenes, indicating that properties such as
electronic conductivity and surface chemistry will be different. In general,
the carbides and nitrides behave differently with the same functional groups.


title:
Local convergence of inexact Gauss-Newton like methods for
  injective-overdetermined systems of equations under a majorant condition

abstract:
  In this paper, inexact Gauss-Newton like methods for solving
injective-overdetermined systems of equations are studied. We use a majorant
condition, defined by a function whose derivative is not necessarily convex, to
extend and improve several existing results on the local convergence of the
Gauss-Newton methods.In particular, this analysis guarantees the convergence of
the methods for two important new cases.


title: Combinatorial operads from monoids

abstract:
  We introduce a functorial construction which, from a monoid, produces a
set-operad. We obtain new (symmetric or not) operads as suboperads or quotients
of the operads obtained from usual monoids such as the additive and
multiplicative monoids of integers and cyclic monoids. They involve various
familiar combinatorial objects: endofunctions, parking functions, packed words,
permutations, planar rooted trees, trees with a fixed arity, Schr\"oder trees,
Motzkin words, integer compositions, directed animals, and segmented integer
compositions. We also recover some already known (symmetric or not) operads:
the magmatic operad, the associative commutative operad, the diassociative
operad, and the triassociative operad. We provide presentations by generators
and relations of all constructed nonsymmetric operads.


title:
Nuclear \sigma-terms and Scalar-Isoscalar WIMP-Nucleus Interactions from
  Lattice QCD

abstract:
  It has been argued that the leading scalar-isoscalar WIMP-nucleus
interactions receive parametrically enhanced contributions in the context of
nuclear effective field theories. These contributions arise from meson-exchange
currents (MECs) and potentially modify the impulse approximation estimates of
these interactions by 10--60%. We point out that these MECs also contribute to
the quark mass dependence of nuclear binding energies, that is, nuclear
\sigma-terms. In this work, we use recent lattice QCD calculations of the
binding energies of the deuteron, He-3 and He-4 at pion masses near 500 MeV and
800 MeV, combined with the experimentally determined binding energies at the
physical point, to provide approximate determinations of the \sigma-terms for
these light nuclei. For each nucleus, we find that the deviation of the
corresponding nuclear \sigma-term from the single-nucleon estimate is at the
few percent level, in conflict with the conjectured enhancement. As a
consequence, lattice QCD calculations currently indicate that the cross
sections for scalar-isoscalar WIMP-nucleus interactions arising from
fundamental WIMP interactions with quarks do not suffer from significant
uncertainties due to enhanced meson-exchange currents.


title: Graphene-based quantum capacitance wireless vapor sensors

abstract:
  A wireless vapor sensor based upon the quantum capacitance effect in graphene
is demonstrated. The sensor consists of a metal-oxide-graphene variable
capacitor (varactor) coupled to an inductor, creating a resonant oscillator
circuit. The resonant frequency is found to shift in proportion to water vapor
concentration for relative humidity (RH) values ranging from 1% to 97% with a
linear frequency shift of 5.7 +- 0.3 kHz / RH%. The capacitance values
extracted from the wireless measurements agree with those determined from
capacitance-voltage measurements, providing strong evidence that the sensing
arises from the variable quantum capacitance in graphene. These results
represent a new sensor transduction mechanism and pave the way for graphene
quantum capacitance sensors to be studied for a wide range of chemical and
biological sensing applications.


title: Log-TQFT and torsion

abstract:
  Logarithmic representations of the bordism category are considered as a
framework for capturing a class of additive invariants characterising
Reidemeister torsions.

categories: math.AT math-ph math.AP math.CT math.DG math.MP


title: Beyond linear gyrocenter polarization in gyrokinetic theory

abstract:
  The concept of polarization in gyrokinetic theory is clarified and
generalized to include contributions from the guiding-center (zeroth-order)
polarization as well as the nonlinear (second-order) gyrocenter polarization.
The guiding-center polarization, which appears as the antecedent (zeroth-order)
of the standard linear (first-order) gyrocenter polarization, is obtained from
a modified guiding-center transformation. The nonlinear gyrocenter polarization
is derived either variationally from the third-order gyrocenter Hamiltonian or
directly by gyrocenter push-forward method.


title:
A PTAS for the Classical Ising Spin Glass Problem on the Chimera Graph
  Structure

abstract:
  We present a polynomial time approximation scheme (PTAS) for the minimum
value of the classical Ising Hamiltonian with linear terms on the Chimera graph
structure as defined in the recent work of McGeoch and Wang. The result follows
from a direct application of the techniques used by Bansal, Bravyi and Terhal
who gave a PTAS for the same problem on planar and, in particular, grid graphs.
We also show that on Chimera graphs, the trivial lower bound is within a
constant factor of the optimum.


title: The DeLiVerMATH project - Text analysis in mathematics

abstract:
  A high-quality content analysis is essential for retrieval functionalities
but the manual extraction of key phrases and classification is expensive.
Natural language processing provides a framework to automatize the process.
Here, a machine-based approach for the content analysis of mathematical texts
is described. A prototype for key phrase extraction and classification of
mathematical texts is presented.


title:
Leakage of power from dipole to higher multipoles due to non-symmetric
  WMAP beam

abstract:
  A number of studies of WMAP and Planck have highlighted that the power at the
low multipoles in CMB power spectrum are lower than their theoretically
predicted values. Possible angular correlation between the orientations of
these low multipoles have also been claimed. It is important to investigate the
possibility that the power deficiency at low multipoles may not be of
primordial origin and is only an observation artifact coming from the scan
procedure adapted in the WMAP or Planck satellites. Therefore, its always
important to investigate all the observational artifacts that can mimic them.
The CMB dipole which is almost 550 times higher than the quadrupole can leak to
the higher multipoles due to the non-symmetric beam shape of the WMAP. In this
paper a formalism has been developed and simulations are carried out to study
the effect of the non-symmetric beam on this power transfer. It is interesting
to observed that a small but non-negligible amount of power from the dipole can
get transferred to the quadrupole and the higher multipoles due to the
non-symmetric beam. It is shown that in case of WMAP scan strategy the shape of
the quadrupole coming due to this power leakage is very much similar to the
observed quadrupole from WMAP data. Simulations have also been carried out for
Planck scan strategy. It is seen that for Planck scan strategy the power
transfer is not only limited to the quadrupole but also to a few higher low
multipoles. Since the actual beam shapes of Planck are not publicly available
we present results in terms of upper limits on asymmetric beam parameters that
would contaminate of the quadrupole power at the level of $1\mu K$.


title: Quantum quasicrystals of spin-orbit coupled dipolar bosons

abstract:
  We study quasi-two-dimensional dipolar Bose gases in which the bosons
experience a Rashba spin-orbit coupling. We show that the degenerate dispersion
minimum due to the spin-orbit coupling, combined with the long-range dipolar
interaction, can stabilize a number of quantum crystalline and quasicrystalline
ground states. Coupling the bosons to a fermionic species can further stabilize
these phases. We estimate that the crystalline and quasicrystalline phases
should be detectable in realistic dipolar condensates, e.g., dysprosium, and
discuss their symmetries and excitations.


title:
Larger sizes of massive quiescent early-type galaxies in clusters than
  in the field at 0.8 < z < 1.5

abstract:
  [abridged] The mass-size relation of early-type galaxies (ETGs) has been
largely studied in the last years to probe the mass assembly of the most
massive objects in the Universe. In this paper, we focus on the mass-size
relation of quiescent massive ETGs (Mstar/Msol > 3*10^10) living in massive
clusters (M200 ~ 10^14 Mstar) at 0.8< z <1.5, as compared to those living in
the field at the same epoch. Our sample contains ~ 400 ETGs in clusters and the
same number in the field. Therefore, our sample is approximately an order of
magnitude larger than previous studies in the same redshift range for galaxy
clusters. We find that ETGs living in clusters are between ~30-50% larger than
galaxies with the same stellar mass residing in the field. We parametrize the
size using the mass-normalized size, gamma=Re/Mstar^0.57. The gamma
distributions in both environments peak at the same position but the
distributions in clusters are more skewed towards larger sizes. Since this size
difference is not observed in the local Universe, the size evolution at fixed
stellar mass from z~1.5 of cluster galaxies is less steep ((1+z)-0.53pm0.04)
than the evolution of field galaxies ((1+z)-0.92pm0.04).
  The size difference seems to be essentially driven by the galaxies residing
in the clusters cores (R<0.5*R200). If part of the size evolution is due to
mergers, the difference we see between cluster and field galaxies could be due
to higher merger rates in clusters at higher redshift, probably during the
formation phase of the clusters when velocity dispersions are lower. We cannot
exclude however that the difference is driven by newly quenched galaxies which
are quenched more efficiently in clusters. The implications of these results
for the hierarchical growth of ETGs will be discussed in a companion paper.


title:
Non-Fermi liquid fixed point in a Wilsonian theory of quantum critical
  metals

abstract:
  We study the problem of disorder-free metals near a continuous quantum
critical point. We depart from the standard paradigm of Hertz and Millis, and
treat both fermions and bosons i.e. order parameter fields) on equal footing.
We construct a Wilsonian effective field theory that integrates out only high
energy boson and fermion modes. Below the upper critical dimension of the
theory (d=3 spatial dimensions), we find new fixed points in which the bosons
are described by the Wilson-Fisher fixed point and are coupled to a non-Fermi
liquid metal. We describe subtleties with the renormalization group flow of
four-Fermi interactions, which can be surmounted in a controlled large N limit.
In this limit, we find that the theory has no superconducting instability.


title: Extra U(1), effective operators, anomalies and dark matter

abstract:
  A general analysis is performed on the dimension-six operators mixing an
almost hidden Z' to the Standard Model (SM), when the Z' communicates with the
SM via heavy mediators. These are fermions charged under both Z' and the SM,
while all SM fermions are neutral under Z'. We classify the operators as a
function of the gauge anomalies behaviour of mediators and explicitly compute
the dimension-six operators coupling Z' to gluons, generated at one-loop by
chiral but anomaly-free, sets of fermion mediators. We prove that only one
operator contribute to the couplings between Z' charged matter and on-shell
gluons. We then make a complete phenomenological analysis of the scenario where
the lightest fermion charged under Z' is the dark matter candidate. Combining
results from WMAP/PLANCK data, mono-jet searches at LHC, and direct/indirect
dark matter detections restrict considerably the allowed parameter space.


title:
Probing real-space and time resolved correlation functions with
  many-body Ramsey interferometry

abstract:
  We propose to use Ramsey interferometry and single-site addressability,
available in synthetic matter such as cold atoms or trapped ions, to measure
real-space and time resolved spin correlation functions. These correlation
functions directly probe the excitations of the system, which makes it possible
to characterize the underlying many-body states. Moreover they contain valuable
information about phase transitions where they exhibit scale invariance. We
also discuss experimental imperfections and show that a spin-echo protocol can
be used to cancel slow fluctuations in the magnetic field. We explicitly
consider examples of the two-dimensional, antiferromagnetic Heisenberg model
and the one-dimensional, long-range transverse field Ising model to illustrate
the technique.


title: Towards an understanding of jet substructure

abstract:
  We present first analytic, resummed calculations of the rates at which
widespread jet substructure tools tag QCD jets. As well as considering
trimming, pruning and the mass-drop tagger, we introduce modified tools with
improved analytical and phenomenological behaviours. Most taggers have double
logarithmic resummed structures. The modified mass-drop tagger is special in
that it involves only single logarithms, and is free from a complex class of
terms known as non-global logarithms. The modification of pruning brings an
improved ability to discriminate between the different colour structures that
characterise signal and background. As we outline in an extensive
phenomenological discussion, these results provide valuable insight into the
performance of existing tools and help lay robust foundations for future
substructure studies.


title: Streams in the Aquarius stellar haloes

abstract:
  We use the very high resolution, fully cosmological simulations from the
Aquarius project, coupled to a semi-analytical model of galaxy formation, to
study the phase-space distribution of halo stars in "solar neighbourhood"-like
volumes. We find that this distribution is very rich in substructure in the
form of stellar streams for all five stellar haloes we have analysed. These
streams can be easily identified in velocity space, as well as in spaces of
pseudo-conserved quantities such as E vs. Lz. In our best-resolved local
volumes, the number of identified streams ranges from ~ 300 to 600, in very
good agreement with previous analytical predictions, even in the presence of
chaotic mixing. The fraction of particles linked to (massive) stellar streams
in these volumes can be as large as 84%. The number of identified streams is
found to decrease as a power-law with galactocentric radius. We show that the
strongest limitation to the quantification of substructure in our
poorest-resolved local volumes is particle resolution rather than strong
diffusion due to chaotic mixing.


title: Vector meson production at low x from gauge/gravity duality

abstract:
  We use gauge/gravity duality to study vector meson (J/{\Psi}, {\rho}_0,
{\Omega}, {\Phi}) production in electron-proton scattering, in the limit of
high center of mass energy at fixed momentum transfer, corresponding to the
limit of low Bjorken x, where the process is dominated by pomeron exchange. Our
approach considers the pomeron at strong coupling, described by the graviton
Regge trajectory in AdS space with a hard-wall to mimic confinement effects.
Both the proton and vector mesons are described by simple holographic wave
functions in AdS. This model agrees with HERA H1 data with a {\chi}^2 per
degree of freedom below one on total cross-sections, and below two on
differential cross-sections, confirming the success of previous studies that
model low x DIS and DVCS using gauge/gravity duality.


title: Tearing up the disc: misaligned accretion on to a binary

abstract:
  In a recent paper we have shown that the evolution of a misaligned disc
around a spinning black hole can result in tearing the disc into many distinct
planes. Tearing discs with random orientations produce direct dynamical
accretion on to the hole in approximately 70% of all cases. Here we examine the
evolution of a misaligned disc around a binary system. We show that these discs
are susceptible to tearing for almost all inclinations. We also show that
tearing of the disc can result in a significant acceleration of the disc
evolution and subsequent accretion on to the binary - by factors up to 10,000
times that of a coplanar prograde disc with otherwise identical parameters.
This provides a promising mechanism for driving mergers of supermassive black
hole (SMBH) binaries on timescales much shorter than a Hubble time. Disc
tearing also suggests new observational signatures of accreting SMBH binaries,
and other systems such as protostellar binaries.


title: Virial scaling of galaxies in clusters: bright to faint is cool to hot

abstract:
  By combining galaxy tracers from high-resolution N-body and hydrodynamical
simulations, we present a consistent picture of the behaviour of galaxy
velocities in massive clusters. In haloes above ~ 10^14 Msun, the brightest
satellite galaxies are slightly cooler compared to the dark matter, while
fainter satellites are hotter. Within the virial radius of a cluster, the mean
velocity dispersion based on the 100 brightest galaxies is a factor of 1.065
+/- 0.005 (stat) +/- 0.027 (sys) higher than that of the dark matter
(corresponding to a ~10-15 per cent bias in the dynamical mass estimate) while
that based on only the five brightest galaxies is 0.868 +/- 0.039 (stat) +/-
0.035 (sys). These trends are approximately independent of redshift. The
velocity structure is sensitive to the modelling of galaxies in clusters,
indicative of the complex interplay of tidal stripping, dynamical friction, and
merging. Velocity dispersions derived from instantaneous subhalo properties are
larger than those employing either peak subhalo properties or hydrodynamical
galaxy tracers. The latter two methods are consistent, implying that stacked
spectroscopic analysis of cluster samples should, after correction for
projection, show a trend towards slightly higher velocities when fainter
galaxies are included, with an unbiased measure of dark matter velocity
dispersion coming from approximately 30 galaxies per cluster. We show evidence
that the velocity distribution function of bright galaxies near the cluster
centre has a low-velocity tail due to strong dynamical friction.


title: Thermal Stability in Turbulently Mixed Accretion Discs

abstract:
  The standard thin accretion disc model predicts that discs around stellar
mass black holes become radiation pressure dominated and thermally unstable
once their luminosity exceeds L>0.02 L_Edd. Observationally, discs in the
high/soft state of X-ray binaries show little variability in the range 0.01
L_Edd < L < 0.5 L_Edd, implying that these discs in nature are in fact quite
stable. In an attempt to reconcile this conflict, we investigate one-zone disc
models including turbulent and convective modes of vertical energy transport.
We find both mixing mechanisms to have a stabilizing effect, leading to an
increase in the L threshold up to which the disc is thermally stable. In the
case of stellar mass black hole systems, convection alone leads to only a minor
increase in this threshold, up to ~5 per cent of Eddington. However turbulent
mixing has a much greater effect -- the threshold rises up to ~20 per cent
Eddington under reasonable assumptions. In optimistic models with
superefficient turbulent mixing, we even find solutions that are completely
thermally stable for all accretion rates. Similar results are obtained for
supermassive black holes, except that all critical accretion rates are a factor
~10 lower in Eddington ratio.


title: Jet substructure with analytical methods

abstract:
  We consider the mass distribution of QCD jets after the application of jet
substructure methods, specifically the mass-drop tagger, pruning, trimming and
their variants. In contrast to most current studies employing Monte Carlo
methods, we carry out analytical calculations at the next-to-leading order
level, which are sufficient to extract the dominant logarithmic behaviour for
each technique, and compare our findings to exact fixed-order results. Our
results should ultimately lead to a better understanding of these jet
substructure methods which in turn will influence the development of future
substructure tools for LHC phenomenology.


title:
Optimal Binary Codes and Measurements for Classical Communication over
  Qubit Channels

abstract:
  We propose constructive approaches for the optimization of binary classical
communication over a general noisy qubit quantum channel, for both the error
probability and the classical capacity functionals. After showing that the
optimal measurements are always associated to orthogonal projections, we
construct a parametrization of the achievable transition probabilities via the
coherence vector representation. We are then able to rewrite the problem in a
form that can be solved by standard, efficient numerical algorithms and
provides insights on the form of the solutions.


title: Realistic Control of Network Dynamics

abstract:
  The control of complex networks is of paramount importance in areas as
diverse as ecosystem management, emergency response, and cell reprogramming. A
fundamental property of networks is that perturbations to one node can affect
other nodes, potentially causing the entire system to change behavior or fail.
Here, we show that it is possible to exploit the same principle to control
network behavior. Our approach accounts for the nonlinear dynamics inherent to
real systems, and allows bringing the system to a desired target state even
when this state is not directly accessible due to constraints that limit the
allowed interventions. Applications show that this framework permits
reprogramming a network to a desired task as well as rescuing networks from the
brink of failure---which we illustrate through the mitigation of cascading
failures in a power-grid network and the identification of potential drug
targets in a signaling network of human cancer.

categories: cond-mat.dis-nn math.OC nlin.AO physics.soc-ph q-bio.MN


title:
The Cosmic Infrared Background Experiment (CIBER): the Narrow Band
  Spectrometer

abstract:
  We have developed a near-infrared spectrometer designed to measure the
absolute intensity of the Solar 854.2 nm CaII Fraunhofer line, scattered by
interplanetary dust, in the Zodiacal light spectrum. Based on the known
equivalent line width in the Solar spectrum, this measurement can derive the
Zodiacal brightness, testing models of the Zodiacal light based on morphology
that are used to determine the extragalactic background light in absolute
photometry measurements. The spectrometer is based on a simple high-resolution
tipped filter placed in front of a compact camera with wide-field refractive
optics to provide the large optical throughput and high sensitivity required
for rocket-borne observations. We discuss the instrument requirements for an
accurate measurement of the absolute Zodiacal light brightness, the measured
laboratory characterization, and the instrument performance in flight.


title: A Systematic Analysis of Caustic Methods for Galaxy Cluster Masses

abstract:
  We quantify the expected observed statistical and systematic uncertainties of
the escape velocity as a measure of the gravitational potential and total mass
of galaxy clusters. We focus our attention on low redshift (z < 0.15) clusters,
where large and deep spectroscopic datasets currently exist. Utilizing a suite
of Millennium Simulation semi-analytic galaxy catalogs, we find that the
dynamical mass, as traced by either the virial relation or the escape velocity,
is robust to variations in how dynamical friction is applied to "orphan"
galaxies in the mock catalogs (i.e., those galaxies whose dark matter halos
have fallen below the resolution limit). We find that the caustic technique
recovers the known halo masses (M_200) with a third less scatter compared to
the virial masses. The bias we measure increases quickly as the number of
galaxies used decreases. For N_gal > 25, the scatter in the escape velocity
mass is dominated by projections along the line-of-sight. Algorithmic
uncertainties from the determination of the projected escape velocity profile
are negligible. We quantify how target selection based on magnitude, color, and
projected radial separation can induce small additional biases into the escape
velocity masses. Using N_gal = 150 (25), the caustic technique has a per
cluster scatter in ln(M|M_200) of 0.3 (0.5) and bias 1+/-3% (16+/-5%) for
clusters with masses > 10^14M_solar at z<0.15.


title: Velocity Anisotropy and Shape Bias in the Caustic Technique

abstract:
  We use the Millennium Simulation to quantify the statistical accuracy and
precision of the escape velocity technique for measuring cluster-sized halo
masses at z~0.1. We show that in 3D, one can measure nearly unbiased (<4%) halo
masses (>1.5x10^14 M_solar h^-1) with 10-15% scatter. Line-of-sight projection
effects increase the scatter to ~25%, where we include the known velocity
anisotropies. The classical "caustic" technique incorporates a calibration
factor which is determined from N-body simulations. We derive and test a new
implementation which eliminates the need for calibration and utilizes only the
observables: the galaxy velocities with respect to the cluster mean v, the
projected positions r_p, an estimate of the Navarro-Frenk-White (NFW) density
concentration and an estimate of the velocity anisotropies, beta. We find that
differences between the potential and density NFW concentrations induce a 10%
bias in the caustic masses. We also find that large (100%) systematic errors in
the observed ensemble average velocity anisotropies and concentrations
translate to small (5%-10%) biases in the inferred masses.


title: Pressure Driven Fermi surface reconstruction of chromium

abstract:
  We have observed a massive reconstruction of the Fermi surface of single
crystal chromium as a function of high pressure and high magnetic fields caused
by the spin-flip transition, with multiple new orbits appearing above 0.93 GPa.
Additionally, some orbits have field-induced effective masses of ~0.06-0.07 me,
seen only at high magnetic fields. Based on the temperature insensitivity
displayed by the oscillation amplitudes at these frequencies, we attribute the
orbits to quantum interference rather than to Landau quantization.


title:
Variation of the fine-structure constant: an update of statistical
  analyses with recent data

abstract:
  We analyze the consistency of different astronomical data of the variation in
the fine-structure constant obtained with KECK and VLT. We tested the
consistency using the Student test and confidence intervals. We splited the
data sets in to smaller intervals and grouped them acording to redshift and
angular position. Another statistical analysis is proposed that considers
phenomenological models for the variation in \alpha. Results show consistency
for the reduced intervals for each pair of data sets and suggests that the
variation in \alpha is significant at higher redshifts. Even though the dipole
model seems to be the most accurate phenomenological model, the statistical
analyses indicate that the variation in \alpha might be depending on both
redshift and angular position.


title:
The Efficiency of Second-Order Fermi Acceleration by Weakly Compressible
  MHD Turbulence

abstract:
  We investigate the effects of pitch-angle scattering on the efficiency of
particle heating and acceleration by MHD turbulence using phenomenological
estimates and simulations of non-relativistic test particles interacting with
strong, subsonic MHD turbulence. We include an imposed pitch-angle scattering
rate, which is meant to approximate the effects of high frequency plasma waves
and/or velocity space instabilities. We focus on plasma parameters similar to
those found in the near-Earth solar wind, though most of our results are more
broadly applicable. An important control parameter is the size of the particle
mean free path lambda_{mfp} relative to the scale of the turbulent fluctuations
L. For small scattering rates, particles interact quasi-resonantly with
turbulent fluctuations in magnetic field strength. Scattering increases the
long-term efficiency of this resonant heating by factors of a few-10, but the
distribution function does not develop a significant non-thermal power-law
tail. For higher scattering rates, the interaction between particles and
turbulent fluctuations becomes non-resonant, governed by particles heating and
cooling adiabatically as they encounter turbulent density fluctuations. Rapid
pitch-angle scattering can produce a power-law tail in the proton distribution
function but this requires fine-tuning of parameters. Moreover, in the
near-Earth solar wind, a significant power-law tail cannot develop by this
mechanism because the particle acceleration timescales are longer than the
adiabatic cooling timescale set by the expansion of the solar wind. Our results
thus imply that MHD-scale turbulent fluctuations are unlikely to be the origin
of the v^{-5} tail in the proton distribution function observed in the solar
wind.


title: Herschel Reveals Massive Cold Clumps in NGC 7538

abstract:
  We present the first overview of the Herschel observations of the nearby
high-mass star-forming region NGC 7538, taken as part of the Herschel imaging
study of OB Young Stellar objects (HOBYS) Key Programme. These PACS and SPIRE
maps cover an approximate area of one square degree at five submillimeter and
far-infrared wavebands. We have identified 780 dense sources and classified 224
of those. With the intention of investigating the existence of cold massive
starless or class 0-like clumps that would have the potential to form
intermediate- to high-mass stars, we further isolate 13 clumps as the most
likely candidates for followup studies. These 13 clumps have masses in excess
of 40 M_sun and temperatures below 15 K. They range in size from 0.4 pc to 2.5
pc and have densities between 3x10^3 cm^-3 to 4x10^4 cm^-3. Spectral energy
distributions are then used to characterize their energetics and evolutionary
state through a luminosity-mass diagram. NGC 7538 has a highly filamentary
structure, previously unseen in the dust continuum of existing submillimeter
surveys. We report the most complete imaging to date of a large, evacuated ring
of material in NGC 7538 which is bordered by many cool sources.


title:
Contribution of the twist-3 fragmentation function to single
  transverse-spin asymmetry in SIDIS

abstract:
  We study the contribution of the twist-3 fragmentation function to the single
transverse-spin asymmetry in SIDIS within the framework of the collinear
factorization. Using the Ward-Takahashi identity in QCD, we establish the
collinear twist-3 formalism in the Feynman gauge to calculate its non-pole
contribution to the asymmetry.


title:
Investigation of "Enhancing flexibility and robustness in multi-agent
  task scheduling"

abstract:
  Wilson et al. propose a measure of flexibility in project scheduling problems
and propose several ways of distributing flexibility over tasks without
overrunning the deadline. These schedules prove quite robust: delays of some
tasks do not necessarily lead to delays of subsequent tasks. The number of
tasks that finish late depends, among others, on the way of distributing
flexibility.
  In this paper I study the different flexibility distributions proposed by
Wilson et al. and the differences in number of violations (tasks that finish
too late). I show one factor in the instances that causes differences in the
number of violations, as well as two properties of the flexibility distribution
that cause them to behave differently. Based on these findings, I propose three
new flexibility distributions. Depending on the nature of the delays, these new
flexibility distributions perform as good as or better than the distributions
by Wilson et al.