title: DynaNewton - Accelerating Newton's Method for Machine Learning

abstract:
  Newton's method is a fundamental technique in optimization with quadratic
convergence within a neighborhood around the optimum. However reaching this
neighborhood is often slow and dominates the computational costs. We exploit
two properties specific to empirical risk minimization problems to accelerate
Newton's method, namely, subsampling training data and increasing strong
convexity through regularization. We propose a novel continuation method, where
we define a family of objectives over increasing sample sizes and with
decreasing regularization strength. Solutions on this path are tracked such
that the minimizer of the previous objective is guaranteed to be within the
quadratic convergence region of the next objective to be optimized. Thereby
every Newton iteration is guaranteed to achieve super-linear contractions with
regard to the chosen objective, which becomes a moving target. We provide a
theoretical analysis that motivates our algorithm, called DynaNewton, and
characterizes its speed of convergence. Experiments on a wide range of data
sets and problems consistently confirm the predicted computational savings.


title:
How particles can emerge in a relativistic version of Bohmian Quantum
  Field Theory

abstract:
  It is shown how bosonic material particles can emerge from a covariant
formulation of de Broglie-Bohm theory. The formulation is based on the work of
Nikolic. Material particles are continuous fields, formed as the eigenvalue of
the Schrodinger field operator, evaluated along a Bohmian trajectory.


title:
Exploring connections between statistical mechanics and Green's
  functions for realistic systems. Temperature dependent electronic entropy and
  internal energy from a self-consistent second-order Green's function

abstract:
  Including finite-temperature effects from the electronic degrees of freedom
in electronic structure calculations of semiconductors and metals is desired;
however, in practice it remains exceedingly difficult when using
zero-temperature methods, since these methods require an explicit evaluation of
multiple excited states in order to account for any finite-temperature effects.
Using a Matsubara Green's function formalism remains a viable alternative,
since in this formalism it is easier to include thermal effects and to connect
the dynamic quantities such as the self-energy with static thermodynamic
quantities such as the Helmholtz energy, entropy, and internal energy. However,
despite the promising properties of this formalism, little is know about the
multiple solutions of the non-linear equations present in the self-consistent
Matsubara formalism and only a few cases involving a full Coulomb Hamiltonian
were investigated in the past. Here, to shed some light onto the iterative
nature of the Green's function solutions, we self-consistently evaluate the
thermodynamic quantities for a one-dimensional (1D) hydrogen solid at various
interatomic separations and temperatures using the self-energy approximated to
second-order (GF2). At many points in the phase diagram of this system,
multiple phases such as a metal and an insulator exist, and we are able to
determine the most stable phase from the analysis of Helmholtz energies.
Additionally, we show the evolution of the spectrum of 1D boron nitride (BN) to
demonstrate that GF2 is capable of qualitatively describing the temperature
effects influencing the size of the band gap.


title: Double-Sided Energy Auction Equilibrium Under Price Anticipation

abstract:
  This paper investigates the problem of proportionally fair double sided
energy auction involving buying and selling agents. The grid is assumed to be
operating under islanded mode. A distributed auction algorithm that can be
implemented by an aggregator, as well as a possible approach by which the
agents may approximate price anticipation is considered. Equilibrium conditions
arising due to price anticipation is analyzed. A modified auction to mitigate
the resulting loss in efficiency due to such behavior is suggested. This
modified auction allows the aggregate social welfare of the agents to be
arbitrarily close to that attainable with price taking agents. Next,
equilibrium conditions when the aggregator collects a surcharge price per unit
of energy traded is examined. A biobjective optimization problem is identified
that takes into account both the agents social welfare as well as the
aggregator revenue from the surcharge. Results of extensive simulations, which
corroborate the theoretical analysis, are reported.


title: Mean curvature flow in Fuchsian manifolds

abstract:
  Motivated by questions in detecting minimal surfaces in hyperbolic manifolds,
we study the behavior of geometric flows in complete hyperbolic
three-manifolds. In most cases the flows develop singularities in finite time.
In this paper, we investigate the mean curvature flow in a class of complete
hyperbolic 3-manifolds (Fuchsian manifolds) which are warped products of a
closed surface of genus at least two and the real line. In particular, we prove
that there exists a large class of closed initial surfaces, as geodesic graphs
over the totally geodesic surface $\Sigma$, such that the mean curvature flow
exists for all time and converges to $\Sigma$. This is among the first examples
of converging mean curvature flows of compact hypersurfaces in Riemannian
manifolds. We also provide some useful calculations for the general warped
product setting.


title: Decomposing Treatment Effect Variation

abstract:
  Understanding and characterizing treatment effect variation in randomized
experiments has become essential for going beyond the "black box" of the
average treatment effect. Nonetheless, traditional statistical approaches often
ignore or assume away such variation. In the context of randomized experiments,
this paper proposes a framework for decomposing overall treatment effect
variation into a systematic component explained by observed covariates and a
remaining idiosyncratic component. Our framework is fully randomization-based,
with estimates of treatment effect variation that are entirely justified by the
randomization itself. Our framework can also account for noncompliance, which
is an important practical complication. We make several contributions. First,
we show that randomization-based estimates of systematic variation are very
similar in form to estimates from fully-interacted linear regression and two
stage least squares. Second, we use these estimators to develop an omnibus test
for systematic treatment effect variation, both with and without noncompliance.
Third, we propose an $R^2$-like measure of treatment effect variation explained
by covariates and, when applicable, noncompliance. Finally, we assess these
methods via simulation studies and apply them to the Head Start Impact Study, a
large-scale randomized experiment.


title: The Frontier Fields: Survey Design

abstract:
  The Frontier Fields are a director's discretionary time campaign with HST and
the Spitzer Space Telescope to see deeper into the universe than ever before.
The Frontier Fields combine the power of HST and Spitzer with the natural
gravitational telescopes of massive high-magnification clusters of galaxies to
produce the deepest observations of clusters and their lensed galaxies ever
obtained. Six clusters - Abell 2744, MACSJ0416.1-2403, MACSJ0717.5+3745,
MACSJ1149.5+2223, Abell S1063, and Abell 370 - were selected based on their
lensing strength, sky darkness, Galactic extinction, parallel field
suitability, accessibility to ground-based facilities, HST, Spitzer and JWST
observability, and pre-existing ancillary data. These clusters have been
targeted by the HST ACS/WFC and WFC3/IR with coordinated parallels of adjacent
blank fields for over 840 HST orbits. The Spitzer Space Telescope has dedicated
> 1000 hours of director's discretionary time to obtain IRAC 3.6 and 4.5 micron
imaging to ~26.5, 26.0 ABmag 5-sigma point-source depths in the six cluster and
six parallel Frontier Fields. The Frontier Field parallel fields are the
second-deepest observations thus far by HST with ~29th ABmag 5-sigma point
source depths in seven optical - near-infrared bandpasses. Galaxies behind the
Frontier Field cluster lenses experience typical magnification factors of a
few, with small regions near the critical curves magnified by factors 10-100.
Therefore, the Frontier Field cluster HST images achieve intrinsic depths of
~30-33 magnitudes over very small volumes. Early studies of the Frontier Fields
have probed galaxies fainter than any seen before during the epoch of
reionization 6 < z < 10, mapped out the cluster dark matter to unprecedented
resolution, and followed lensed transient events.


title: Derived categories of Gushel-Mukai varieties

abstract:
  We study the derived categories of coherent sheaves on Gushel-Mukai
varieties. In the derived category of such a variety, we isolate a special
semiorthogonal component, which is a K3 or Enriques category according to
whether the dimension of the variety is even or odd. We analyze the basic
properties of this category using Hochschild homology, Hochschild cohomology,
and the Grothendieck group.
  We study the K3 category of a Gushel-Mukai fourfold in more detail. Namely,
we show that this category is equivalent to the derived category of a K3
surface for a certain codimension 1 family of rational fourfolds, and to the K3
category of a birational cubic fourfold for a certain codimension 3 family. The
first of these results verifies a special case of a duality conjecture which we
formulate. We discuss our results in the context of the rationality problem for
Gushel-Mukai varieties, which was one of the main motivations for this work.


title:
The Atacama Cosmology Telescope: The polarization-sensitive ACTPol
  instrument

abstract:
  The Atacama Cosmology Telescope (ACT) is designed to make high angular
resolution measurements of anisotropies in the Cosmic Microwave Background
(CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for
ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3
degree field of view, 100 mK cryogenics with continuous cooling, and meta
material anti-reflection coatings. ACTPol comprises three arrays with separate
cryogenic optics: two arrays at a central frequency of 148 GHz and one array
operating simultaneously at both 97 GHz and 148 GHz. The combined instrument
sensitivity, angular resolution, and sky coverage are optimized for measuring
angular power spectra, clusters via the thermal Sunyaev-Zel'dovich and kinetic
Sunyaev-Zel'dovich signals, and CMB lensing due to large scale structure. The
receiver was commissioned with its first 148 GHz array in 2013, observed with
both 148 GHz arrays in 2014, and has recently completed its first full season
of operations with the full suite of three arrays. This paper provides an
overview of the design and initial performance of the receiver and related
systems.


title: Sub-Ramsey numbers for arithmetic progressions

abstract:
  Let the integers $1,\ldots,n$ be assigned colors. Szemer\'edi's theorem
implies that if there is a dense color class then there is an arithmetic
progression of length three in that color. We study the conditions on the color
classes forcing totally multicolored arithmetic progressions of length 3.
  Let $f(n)$ be the smallest integer $k$ such that there is a coloring of $\{1,
\ldots, n\}$ without totally multicolored arithmetic progressions of length
three and such that each color appears on at most $k$ integers. We provide an
exact value for $f(n)$ when $n$ is sufficiently large, and all extremal
colorings. In particular, we show that $f(n)= 8n/17 + O(1)$. This completely
answers a question of Alon, Caro and Tuza.


title:
Nuevos resultados sobre la cinem\'atica global y nuclear de NGC 253:
  movimientos no circulares y emisi\'on en Br-gamma

abstract:
  Continuing with previous research (Camperi et al. 2011),new heliocentric
radial velocity distributions are presented for the nearby galaxy NGC 253,
obtained from the ionized hydrogen recombination line H-alpha. These
distributions have been derived from long-slit spectroscopy for various
position angles. It is also shown the heliocentric radial velocity distribution
corresponding to part of the infrared data (ionized hydrogen recombination line
Br-gamma) observed with the Phoenix spectrograph of the Gemini South
Observatory. Sequential mapping with the long slit using this instrument will
enable to study in detail the kinematics of the galaxy's core, which is
strongly obscured by dust.


title: A note on short cycles in a hypercube

abstract:
  How many edges can a quadrilateral-free subgraph of a hypercube have? This
question was raised by Paul Erd\H{o}s about $27$ years ago. His conjecture that
such a subgraph asymptotically has at most half the edges of a hypercube is
still unresolved. Let $f(n,C_l)$ be the largest number of edges in a subgraph
of a hypercube $Q_n$ containing no cycle of length $l$. It is known that $f(n,
C_l) = o(|E(Q_n)|)$, when $l= 4k$, $k\geq 2$ and that $f(n, C_6) \geq
\frac{1}{3} |E(Q_n)|$. It is an open question to determine $f(n, C_l)$ for
$l=4k+2$, $k\geq 2$. Here, we give a general upper bound for $f(n,C_l)$ when
$l=4k+2$ and provide a coloring of $E(Q_n)$ by $4$ colors containing no induced
monochromatic $C_{10}$.


title:
Astrometry of mutual approximations between natural satellites.
  Application to the Galilean moons

abstract:
  Typically we can deliver astrometric positions of natural satellites with
errors in the 50-150 mas range. Apparent distances from mutual phenomena, have
much smaller errors, less than 10 mas. However, this method can only be applied
during the equinox of the planets. We developed a method that can provide
accurate astrometric data for natural satellites -- the mutual approximations.
The method can be applied when any two satellites pass close by each other in
the apparent sky plane. The fundamental parameter is the central instant $t_0$
of the passage when the distances reach a minimum.
  We applied the method for the Galilean moons. All observations were made with
a 0.6 m telescope with a narrow-band filter centred at 889 nm with width of 15
nm which attenuated Jupiter's scattered light. We obtained central instants for
14 mutual approximations observed in 2014-2015. We determined $t_0$ with an
average precision of 3.42 mas (10.43 km). For comparison, we also applied the
method for 5 occultations in the 2009 mutual phenomena campaign and for 22
occultations in the 2014-2015 campaign. The comparisons of $t_0$ determined by
our method with the results from mutual phenomena show an agreement by less
than 1-sigma error in $t_0$, typically less than 10 mas. This new method is
particularly suitable for observations by small telescopes.


title: On the strong chromatic number of graphs

abstract:
  The strong chromatic number, $\chi_S(G)$, of an $n$-vertex graph $G$ is the
smallest number $k$ such that after adding $k\lceil n/k\rceil-n$ isolated
vertices to $G$ and considering {\bf any} partition of the vertices of the
resulting graph into disjoint subsets $V_1, \ldots, V_{\lceil n/k\rceil}$ of
size $k$ each, one can find a proper $k$-vertex-coloring of the graph such that
each part $V_i$, $i=1, \ldots, \lceil n/k\rceil$, contains exactly one vertex
of each color.
  For any graph $G$ with maximum degree $\Delta$, it is easy to see that
$\chi_S(G)\geq\Delta+1$. Recently, Haxell proved that $\chi_S(G) \leq 3\Delta
-1$. In this paper, we improve this bound for graphs with large maximum degree.
We show that $\chi_S(G)\leq 2\Delta$ if $\Delta \geq n/6$ and prove that this
bound is sharp.


title:
Observational Signatures of a Massive Distant Planet on the Scattering
  Disk

abstract:
  The orbital element distribution of trans-Neptunian objects (TNOs) with large
pericenters has been suggested to be influenced by the presence of an
undetected, large planet at >200 AU from the Sun. To find additional
observables caused by this scenario, we here present the first detailed
emplacement simulation in the presence of a massive ninth planet on the distant
Kuiper Belt. We perform 4 Gyr N-body simulations with the currently known Solar
System planetary architecture, plus a 10 Earth mass planet with similar orbital
parameters to those suggested by Trujillo & Sheppard (2014) or Batygin & Brown
(2016), and 10^5 test particles in an initial planetesimal disk. We find that
including a distant superearth-mass planet produces a substantially different
orbital distribution for the scattering and detached TNOs, raising the
pericenters and inclinations of moderate semimajor axis (50<a<500 AU) objects.
We test whether this signature is detectable via a simulator with the
observational characteristics of four precisely characterized TNO surveys. We
find that the qualitatively very distinct Solar System models that include a
ninth planet are essentially observationally indistinguishable from an outer
Solar System produced solely by the four giant planets. We also find that the
mass of the Kuiper Belt's current scattering and detached populations is
required to be 3-10 times larger in the presence of an additional planet. We do
not find any evidence for clustering of orbital angles in our simulated TNO
population. Wide-field, deep surveys targeting inclined high-pericenter objects
will be required to distinguish between these different scenarios.


title: A model for the clustered distribution of SNPs in the human genome

abstract:
  Motivated by a non-random but clustered distribution of SNPs, we introduce a
phenomenological model to account for the clustering properties of SNPs in the
human genome. The phenomenological model is based on a preferential mutation to
the closer proximity of existing SNPs. With the Hapmap SNP data, we empirically
demonstrate that the preferential model is better for illustrating the
clustered distribution of SNPs than the random model. Moreover, the model is
applicable not only to autosomes but also to the X chromosome, although the X
chromosome has different characteristics from autosomes. The analysis of the
estimated parameters in the model can explain the pronounced population
structure and the low genetic diversity of the X chromosome. In addition,
correlation between the parameters reveals the population-wise difference of
the mutation probability. These results support the mutational non-independence
hypothesis against random mutation.


title: Avoiding patterns in matrices via a small number of changes

abstract:
  Let ${\cal A}=\{A_1,\ldots, A_r\}$ be a partition of a set
$\{1,\ldots,m\}\times\{1,\ldots, n\}$ into $r$ nonempty subsets, and
$A=(a_{ij})$ be an $m\times n$ matrix. We say that $A$ has a pattern ${\cal A}$
provided that $a_{ij}=a_{i'j'}$ if and only if $(i,j),(i',j')\in A_t$ for some
$t\in\{1,\ldots,r\}$. In this note we study the following function $f$ defined
on the set of all $m\times n$ matrices $M$ with $s$ distinct entries: $f(M;
{\cal A})$ is the smallest number of positions where the entries of $M$ need to
be changed such that the resulting matrix does not have any submatrix with
pattern ${\cal A}$. We give an asymptotically tight value for $$ f(m,n; s,
{\cal A}) = \max\{f(M; {\cal A}): M \mbox{ is an } m\times n\mbox{ matrix with
at most } s \mbox{ distinct entries}\} . $$


title: Landau-Lifshitz theory of the magnon-drag thermopower

abstract:
  Metallic ferromagnets subjected to a temperature gradient exhibit a magnonic
drag of the electric current. We address this problem by solving a stochastic
Landau-Lifshitz equation to calculate the magnon-drag thermopower. The
long-wavelength magnetic dynamics result in two contributions to the
electromotive force acting on electrons: (1) An adiabatic Berry-phase force
related to the solid angle subtended by the magnetic precession and (2) a
dissipative correction thereof, which is rooted microscopically in the
spin-dephasing scattering. The first contribution results in a net force
pushing the electrons towards the hot side, while the second contribution drags
electrons towards the cold side, i.e., in the direction of the magnonic drift.
The ratio between the two forces is proportional to the ratio between the
Gilbert damping coefficient $\alpha$ and the coefficient $\beta$ parametrizing
the dissipative contribution to the electromotive force.


title: One-dimensional Nonstationary Process Variance Function Estimation

abstract:
  Many spatial processes exhibit nonstationary features. We estimate a variance
function from a single process observation where the errors are nonstationary
and correlated. We propose a difference-based approach for a one-dimensional
nonstationary process and develop a bandwidth selection method for smoothing,
taking into account the correlation in the errors. The estimation results are
compared to that of a local-likelihood approach proposed by Anderes and
Stein(2011). A simulation study shows that our method has a smaller integrated
MSE, easily fixes the boundary bias problem, and requires far less computing
time than the likelihood-based method.


title:
Fabrication of polarization-independent single-mode waveguides in
  lithium niobate crystal with femtosecond laser pulses

abstract:
  We report on fabrication of depressed cladding optical waveguides buried in
lithium niobate crystal with shaped femtosecond laser pulses. Depressed
cladding waveguides of variable mode-field sizes are fabricated by forming the
four sides of the cladding using a slit-beam shaping technique. We show that
the waveguides fabricated by our technique allows single-mode propagation of
the light polarized in both vertical and horizontal directions.


title:
On the Rate of Convergence of the Power-of-Two-Choices to its Mean-Field
  Limit

abstract:
  This paper studies the rate of convergence of the power-of-two-choices, a
celebrated randomized load balancing algorithm for many-server queueing
systems, to its mean field limit. The convergence to the mean-field limit has
been proved in the literature, but the rate of convergence remained to be an
open problem. This paper establishes that the sequence of stationary
distributions, indexed by $M,$ the number of servers in the system, converges
in mean-square to its mean-field limit with rate $O\left(\frac{(\log M)^3
(\log\log M)^2}{M}\right).$


title: Compensation for Booster Leakage Field in the Duke Storage Ring

abstract:
  The High Intensity Gamma-ray Source (HIGS) at Duke University is an
accelerator-driven Compton gamma-ray source, providing high flux gamma-ray beam
from 1 MeV to 100 MeV for photo-nuclear physics research. The HIGS facility
operates three accelerators, a linac pre-injector (0.16 GeV), a booster
injector (0.16-1.2 GeV), and an electron storage ring (0.24-1.2 GeV). Because
of proximity of the booster injector to the storage ring, the magnetic field of
the booster dipoles close to the ring can significantly alter the closed orbit
in the storage ring being operated in the low energy region. This type of orbit
distortion can be a problem for certain precision experiments which demand a
high degree of the energy consistency of the gamma-ray beam. This energy
consistency can be achieved by maintaining consistent aiming of the gamma-ray
beam, therefore, a steady electron beam orbit and angle at the Compton
collision point. To overcome the booster leakage field problem, we have
developed an orbit compensation scheme. This scheme is developed using two fast
orbit correctors and implemented as a feedforward which is operated
transparently together with the slow orbit feedback system. In this paper, we
will describe the development of this leakage field compensation scheme, and
report the measurement results which have demonstrated the effectiveness of the
scheme.


title: Breadth and characteristic sequence of nilpotent Lie algebras

abstract:
  The notion of breadth of a nilpotent Lie algebra was introduced by B.
Khuhirun, K.C. Misra and E. Stitzinger and used to approach problems of
classification up to isomorphism. In the present paper, we study this invariant
in terms of characteristic sequence, another invariant introduced by M. Goze
and J.M. Ancochea-Bermudez. This permits to complete the determination of Lie
algebras of breadth 2 and to begin the work for Lie algebras with breadth
greater than 2.


title:
Amplitude dependence of image quality in atomically-resolved bimodal
  atomic microscopy

abstract:
  In bimodal FM-AFM, two flexural modes are excited simultaneously. The total
vertical oscillation deflection range of the tip is the sum of the peak-to-peak
amplitudes of both flexural modes (sum amplitude). We show atomically resolved
images of KBr(100) in ambient conditions in bimodal AFM that display a strong
correlation between image quality and sum amplitude. When the sum amplitude
becomes larger than about 200 pm, the signal-to-noise ratio (SNR) is
drastically decreased. We propose this is caused by the temporary presence of
one or more water layers in the tip-sample gap. These water layers screen the
short range interaction and must be displaced with each oscillation cycle.
Further decreasing the sum amplitude, however, causes a decrease in SNR.
Therefore, the highest SNR in ambient conditions is achieved when the sum
amplitude is slightly less than the thickness of the primary hydration layer.


title:
Bayesian Analysis of Modified Weibull distribution under progressively
  censored competing risk model

abstract:
  In this paper we study bayesian analysis of Modified Weibull distribution
under progressively censored competing risk model. This study is made for
progressively censored data. We use deterministic scan Gibbs sampling combined
with slice sampling to generate from the posterior distribution. Posterior
distribution is formed by taking prior distribution as reference prior. A real
life data analysis is shown for illustrative purpose.


title: Two No-Go Theorems on Superconductivity

abstract:
  We study lattice superconductors such as attractive Hubbard models. As is
well known, Bloch's theorem asserts absence of persistent current in ground
states and equilibrium states for general fermion systems. While the statement
of the theorem is true, we can show that the theorem cannot exclude possibility
of a surface persistent current. Such a current can be stabilized by boundary
magnetic fields which do not penetrate into the bulk region of a
superconductor, provided emergence of massive photons, i.e., Meissner effect.
Therefore, we can expect that a surface persistent current is realized for a
ground/equilibrium state in the sense of stability against local perturbations.
We also apply Elitzur's theorem to superconductors at finite temperatures. As a
result, we prove absence of symmetry breaking of the global $U(1)$ phase of
electrons for almost all gauge fields. These observations suggest that the
nature of superconductivity is the emergence of massive photons rather than the
symmetry breaking of the $U(1)$ phase of electrons.

categories: math-ph cond-mat.str-el cond-mat.supr-con hep-lat hep-th math.MP


title: Optical disassembly of cellular clusters by tunable tug-of-war tweezers

abstract:
  Bacterial biofilms underlie many persistent infections, posing major hurdles
in antibiotic treatment. Here, we design and demonstrate tug-of-war optical
tweezers that can facilitate assessment of cell-cell adhesion - a key
contributing factor to biofilm development, thanks to the combined actions of
optical scattering and gradient forces. With a customized optical landscape
distinct from that of conventional tweezers, not only can such tug-of-war
tweezers stably trap and stretch a rod-shaped bacterium in the observing plane,
but, more importantly, they can also impose a tunable lateral force that pulls
apart cellular clusters without any tethering or mechanical movement. As a
proof of principle, we examined a Sinorhizobium meliloti strain that forms
robust biofilms and found that the strength of intercellular adhesion depends
on the growth medium. This technique may herald new photonic tools for optical
manipulation and biofilm study, as well as other biological applications.


title: Optimal Number of Choices in Rating Contexts

abstract:
  In many settings people must give numerical scores to entities from a small
discrete set. For instance, rating physical attractiveness from 1--5 on dating
sites, or papers from 1--10 for conference reviewing. We study the problem of
understanding when using a different number of options is optimal. We consider
the case when scores are uniform random and Gaussian. We study computationally
when using 2, 3, 4, 5, and 10 options out of a total of 100 is optimal in these
models (though our theoretical analysis is for a more general setting with $k$
choices from $n$ total options as well as a continuous underlying space). One
may expect that using more options would always improve performance in this
model, but we show that this is not necessarily the case, and that using fewer
choices---even just two---can surprisingly be optimal in certain situations.
While in theory for this setting it would be optimal to use all 100 options, in
practice this is prohibitive, and it is preferable to utilize a smaller number
of options due to humans' limited computational resources. Our results could
have many potential applications, as settings requiring entities to be ranked
by humans are ubiquitous. There could also be applications to other fields such
as signal or image processing where input values from a large set must be
mapped to output values in a smaller set.

categories: cs.AI cs.IT cs.SI eess.SP math.IT math.PR


title:
Large compact clusters and fast dynamics in coupled nonequilibrium
  systems

abstract:
  We demonstrate particle clustering on macroscopic scales in a coupled
nonequilibrium system where two species of particles are advected by a
fluctuating landscape and modify the landscape in the process. The phase
diagram generated by varying the particle-landscape coupling, valid for all
particle density and in both one and two dimensions, shows novel nonequilibrium
phases. While particle species are completely phase separated, the landscape
develops macroscopically ordered regions coexisting with a disordered region,
resulting in coarsening and steady state dynamics on time scales which grow
algebraically with size, not seen earlier in systems with pure domains.


title: Local Matrix Homotopies and Soft Tori

abstract:
  We present solutions to local connectivity problems in matrix representations
of the form $C([-1,1]^{N}) \to A_{n,\varepsilon} \leftarrow
C_{\varepsilon}(\mathbb{T}^{2})$ for any $\varepsilon\in[0,2]$ and any integer
$n\geq 1$, where $A_{n,\varepsilon}\subseteq M_n$ and where
$C_{\varepsilon}(\mathbb{T}^{2})$ denotes the {\bf Soft Torus}. We solve the
connectivity problems by introducing the so called toroidal matrix links, which
can be interpreted as normal contractive matrix analogies of free homotopies in
differential algebraic topology.
  In order to deal with the locality constraints, we have combined some
techniques introduced in this document with some techniques from matrix
geometry, combinatorial optimization, classification and representation theory
of C$^*$-algebras.


title:
Average spatial distribution of cosmic rays behind the interplanetary
  shock -Global Muon Detector Network observations-

abstract:
  We analyze the galactic cosmic ray (GCR) density and its spatial gradient in
Forbush Decreases (FDs) observed with the Global Muon Detector Network (GMDN)
and neutron monitors (NMs). By superposing the GCR density and density gradient
observed in FDs following 45 interplanetary shocks (IP-shocks), each associated
with an identified eruption on the sun, we infer the average spatial
distribution of GCRs behind IP-shocks. We find two distinct modulations of GCR
density in FDs, one in the magnetic sheath and the other in the coronal mass
ejection (CME) behind the sheath. The density modulation in the sheath is
dominant in the western flank of the shock, while the modulation in the CME
ejecta stands out in the eastern flank. This east-west asymmetry is more
prominent in GMDN data responding to $\sim$ 60 GV GCRs than in NM data
responding to $\sim$ 10 GV GCRs, because of softer rigidity spectrum of the
modulation in the CME ejecta than in the sheath. The GSE-y component of the
density gradient, $G_y$ shows a negative (positive) enhancement in FDs caused
by the eastern (western) eruptions, while $G_z$ shows a negative (positive)
enhancement in FDs by the northern (southern) eruptions. This implies the GCR
density minimum being located behind the central flank of IP-shock and
propagating radially outward from location of the solar eruption. We also
confirmed the average $G_z$ changing its sign above and below the heliospheric
current sheet, in accord with the prediction of the drift model for the
large-scale GCR transport in the heliosphere.


title: A local regularity theorem for mean curvature flow with triple edges

abstract:
  Mean curvature flow of clusters of n-dimensional surfaces in R^{n+k} that
meet in triples at equal angles along smooth edges and higher order junctions
on lower dimensional faces is a natural extension of classical mean curvature
flow. We call such a flow a mean curvature flow with triple edges. We show that
if a smooth mean curvature flow with triple edges is weakly close to a static
union of three n-dimensional unit density half-planes, then it is smoothly
close. Extending the regularity result to a class of integral Brakke flows, we
show that this implies smooth short-time existence of the flow starting from an
initial surface cluster that has triple edges, but no higher order junctions.


title:
Online Influence Maximization under Independent Cascade Model with
  Semi-Bandit Feedback

abstract:
  We study the online influence maximization problem in social networks under
the independent cascade model. Specifically, we aim to learn the set of "best
influencers" in a social network online while repeatedly interacting with it.
We address the challenges of (i) combinatorial action space, since the number
of feasible influencer sets grows exponentially with the maximum number of
influencers, and (ii) limited feedback, since only the influenced portion of
the network is observed. Under a stochastic semi-bandit feedback, we propose
and analyze IMLinUCB, a computationally efficient UCB-based algorithm. Our
bounds on the cumulative regret are polynomial in all quantities of interest,
achieve near-optimal dependence on the number of interactions and reflect the
topology of the network and the activation probabilities of its edges, thereby
giving insights on the problem complexity. To the best of our knowledge, these
are the first such results. Our experiments show that in several representative
graph topologies, the regret of IMLinUCB scales as suggested by our upper
bounds. IMLinUCB permits linear generalization and thus is both statistically
and computationally suitable for large-scale problems. Our experiments also
show that IMLinUCB with linear generalization can lead to low regret in
real-world online influence maximization.


title:
Analyses of kinetic glass transition in short-range attractive colloids
  based on time-convolutionless mode-coupling theory

abstract:
  The kinetic glass transition in short-range attractive colloids is
theoretically studied by time-convolutionless mode-coupling theory (TMCT). By
numerical calculations, TMCT is shown to recover all the remarkable features
predicted by the mode-coupling theory for attractive colloids, namely the
glass-liquid-glass reentrant, the glass-glass transition, and the higher-order
singularities. It is also demonstrated through the comparisons with the results
of molecular dynamics for the binary attractive colloids that TMCT improves the
critical values of the volume fraction. In addition, a schematic model of three
control parameters is investigated analytically. It is thus confirmed that TMCT
can describe the glass-glass transition and higher-order singularities even in
such a schematic model.


title:
WAHRSIS: A Low-cost, High-resolution Whole Sky Imager With Near-Infrared
  Capabilities

abstract:
  Cloud imaging using ground-based whole sky imagers is essential for a
fine-grained understanding of the effects of cloud formations, which can be
useful in many applications. Some such imagers are available commercially, but
their cost is relatively high, and their flexibility is limited. Therefore, we
built a new daytime Whole Sky Imager (WSI) called Wide Angle High-Resolution
Sky Imaging System. The strengths of our new design are its simplicity, low
manufacturing cost and high resolution. Our imager captures the entire
hemisphere in a single high-resolution picture via a digital camera using a
fish-eye lens. The camera was modified to capture light across the visible as
well as the near-infrared spectral ranges. This paper describes the design of
the device as well as the geometric and radiometric calibration of the imaging
system.


title: Cohomological orientifold Donaldson-Thomas invariants as Chow groups

abstract:
  We establish a geometric interpretation of orientifold Donaldson-Thomas
invariants of $\sigma$-symmetric quivers with involution. More precisely, we
prove that the cohomological orientifold Donaldson-Thomas invariant is
isomorphic to the rational Chow group of the moduli space of $\sigma$-stable
self-dual quiver representations. As an application we prove that the Chow
Betti numbers of moduli spaces of stable $m$-tuples in classical Lie algebras
can be computed numerically. We also prove a cohomological wall-crossing
formula relating semistable Hall modules for different stabilities.


title:
Adaptive Algorithm and Platform Selection for Visual Detection and
  Tracking

abstract:
  Computer vision algorithms are known to be extremely sensitive to the
environmental conditions in which the data is captured, e.g., lighting
conditions and target density. Tuning of parameters or choosing a completely
new algorithm is often needed to achieve a certain performance level,
especially when there is a limitation of the computation source. In this paper,
we focus on this problem and propose a framework to adaptively select the
"best" algorithm-parameter combination and the computation platform under
performance and cost constraints at design time, and adapt the algorithms at
runtime based on real-time inputs. This necessitates developing a mechanism to
switch between different algorithms as the nature of the input video changes.
Our proposed algorithm calculates a similarity function between a test video
scenario and each training scenario, where the similarity calculation is based
on learning a manifold of image features that is shared by both the training
and test datasets. Similarity between training and test dataset indicates the
same algorithm can be applied to both of them and achieve similar performance.
We design a cost function with this similarity measure to find the most similar
training scenario to the test data. The "best" algorithm under a given platform
is obtained by selecting the algorithm with a specific parameter combination
that performs the best on the corresponding training data. The proposed
framework can be used first offline to choose the platform based on performance
and cost constraints, and then online whereby the "best" algorithm is selected
for each new incoming video segment for a given platform. In the experiments,
we apply our algorithm to the problems of pedestrian detection and tracking. We
show how to adaptively select platforms and algorithm-parameter combinations.
Our results provide optimal performance on 3 publicly available datasets.


title:
The missing link: tracing molecular gas in the outer filament of
  Centaurus A

abstract:
  We report the detection, using observations of the CO(2-1) line performed
with the Atacama Pathfinder EXperiment (APEX), of molecular gas in the region
of the outer filament of Centaurus A, a complex region known to show various
signatures of an interaction between the radio jet, an HI cloud, and ionised
gas filaments. We detect CO(2-1) at all observed locations, which were selected
to represent regions with very different physical conditions. The H_2 masses of
the detections range between 0.2 x 10^6 and 1.1 x 10^6 \msun, for conservative
choices of the CO to H_2 conversion factor. Surprisingly, the stronger
detections are not coincident with the HI cloud, but instead are in the region
of the ionised filaments. We also find variations in the widths of the CO(2-1)
lines throughout the region, with broader lines in the region of the ionised
gas, i.e. where the jet--cloud interaction is strongest, and with narrow
profiles in the HI cloud. This may indicate that the molecular gas in the
region of the ionised gas has the momentum of the jet-cloud interaction encoded
in it, in the same way as the ionised gas does. These molecular clouds may
therefore be the result of very efficient cooling of the down-stream gas photo-
or shock-ionised by the interaction. On the other hand, the molecular clouds
with narrower profiles, which are closer to or inside the HI cloud, could be
pre-existing cold H_2 cores which manage to survive the effects of the passing
jet.


title:
An inverse problem for the magnetic Schr\"odinger equation in infinite
  cylindrical domains

abstract:
  We study the inverse problem of determining the magnetic field and the
electric potential entering the Schr\"odinger equation in an infinite 3D
cylindrical domain, by Dirichlet-to-Neumann map. The cylindrical domain we
consider is a closed waveguide in the sense that the cross section is a bounded
domain of the plane. We prove that the knowledge of the Dirichlet-to-Neumann
map determines uniquely, and even H\"older-stably, the magnetic field induced
by the magnetic potential and the electric potential. Moreover, if the maximal
strength of both the magnetic field and the electric potential, is attained in
a fixed bounded subset of the domain, we extend the above results by taking
finitely extended boundary observations of the solution, only.


title: Non-local form factors for curved-space antisymmetric fields

abstract:
  In the recent paper Buchbinder, Kirillova and Pletnev presented formal
arguments concerning quantum equivalence of free massive antisymmetric tensor
fields of second and third rank to the free Proca theory and massive scalar
field with minimal coupling to gravity, respectively. We confirm this result
using explicit covariant calculations of non-local form factors based on the
heart-kernel technique, and discuss the discontinuity of quantum contributions
in the massless limit.


title:
Investigation of the solutions of the Cauchy problem and boundary-value
  problems for the ordinary differential equations with continuously changing
  order of the derivative

abstract:
  As is known, the problems for the differential equations with continuously
changing order of the derivatives are not considered completely. In this paper
we consider the initial and boundary value problems for this type of linear
ordinary differential equations with constant coefficients and obtain analytic
representations of solutions of these problems. It should be noted that this
area is one of the less studied fields of modern mathematics and there are not
effective methods for the study of problems for such differential equations,
just as we study the problem for partial differential equations, with both with
additive and a multiplicative derivatives. The method used here is based on an
invariant for the above mentioned derivative, i.e. on the functions that do not
change for the derivative of any real positive order.


title: Mean curvature in manifolds with Ricci curvature bounded from below

abstract:
  Let $M$ be a compact Riemannian manifold of nonnegative Ricci curvature and
$\Sigma$ a compact embedded 2-sided minimal hypersurface in $M$. It is proved
that there is a dichotomy: If $\Sigma$ does not separate $M$ then $\Sigma$ is
totally geodesic and $M\setminus\Sigma$ is isometric to the Riemannian product
$\Sigma\times(a,b)$, and if $\Sigma$ separates $M$ then the map
$i_*:\pi_1(\Sigma)\rightarrow \pi_1(M)$ induced by inclusion is surjective.
This surjectivity is also proved for a compact 2-sided hypersurface with mean
curvature $H\geq(n-1)\sqrt{k}$ in a manifold of Ricci curvature
$Ric_M\geq-(n-1)k,k>0$, and for a free boundary minimal hypersurface in a
manifold of nonnegative Ricci curvature with nonempty strictly convex boundary.
As an application it is shown that a compact $n$-dimensional manifold $N$ with
the number of generators of $\pi_1(N)<n$ cannot be minimally embedded in the
flat torus $T^{n+1}$.


title:
Study of Rydberg blockade mediated optical non-linearity in thermal
  vapor using optical heterodyne detection technique

abstract:
  We demonstrate the phenomenon of blockade in two-photon excitations to the
Rydberg state in thermal vapor. A technique based on optical heterodyne is used
to measure the dispersion of a probe beam far off resonant to the D2 line of
rubidium in the presence of a strong laser beam that couples to the Rydberg
state via two-photon resonance. Density dependent suppression of the dispersion
peak is observed while coupling to the Rydberg state with principal quantum
number, n = 60. The experimental observation is explained using the phenomenon
of Rydberg blockade. The blockade radius is measured to be about 2.2 {\mu}m
which is consistent with the scaling due to the Doppler width of 2-photon
resonance in thermal vapor. Our result promises the realization of single
photon source and strong single photon non-linearity based on Rydberg blockade
in thermal vapor.


title:
Origin of in-plane anisotropic resistivity in the antiferromagnetic
  phase of Fe$_{1+x}$Te

abstract:
  Motivated by a recent experimental report on in-plane anisotropic resistivity
in the double-striped antiferromagnetic phase of FeTe, we theoretically
calculate in-plane resistivity by applying a memory function approach to the
ordered phase. We find that the resistivity is larger along an
antiferromagnetically ordered direction than along a ferromagnetically ordered
one, consistent with experimental observation. The anisotropic results are
mainly contributed from Drude weight, whose behavior is attributed to Fermi
surface topology of the ordered phase.


title: Propagators of resonances and rescatterings of the decay products

abstract:
  Hadronic resonance propagators which take into account the analytical
properties of decay processes are built in terms of the dispersion relation
technique. Such propagators can describe multi-component systems, for example,
those when quark degrees of freedom create a resonance state, and decay
products correct the corresponding pole by adding hadronic deuteron-like
components. Meson and baryon states are considered, examples of particles with
different spins are presented.


title:
Mapping color fluctuations in the photon in ultraperipheral heavy ion
  collisions at the Large Hadron Collider

abstract:
  We model effects of color fluctuations (CFs) in the light-cone photon wave
function and for the first time make predictions for the distribution over the
number of wounded nucleons $\nu$ in the inelastic photon-nucleus scattering. We
show that CFs lead to a dramatic enhancement of this distribution at $\nu=1$
and large $\nu > 10$. We also study the implications of different scales and
CFs in the photon wave function on the total transverse energy $\Sigma E_T$ and
other observables in inelastic $\gamma A$ scattering with different triggers.
Our predictions can be tested in proton-nucleus and nucleus-nucleus
ultraperipheral collisions at the LHC and will help to map CFs, whose first
indications have already been observed at the LHC.


title:
Measure for degree heterogeneity in complex networks and its application
  to recurrence network analysis

abstract:
  We propose a novel measure of degree heterogeneity, for unweighted and
undirected complex networks, which requires only the degree distribution of the
network for its computation. We show that the proposed measure can be applied
to all types of network topology with ease and increases with the diversity of
node degrees in the network. The measure is applied to compute the
heterogeneity of synthetic (both random and scale free) and real world networks
with its value normalized in the interval [0, 1]. To define the measure, we
introduce a limiting network whose heterogeneity can be expressed analytically
with the value tending to 1 as the size of the network N tends to infinity. We
numerically study the variation of heterogeneity for random graphs (as a
function of p and N) and for scale free networks with and N as variables.
Finally, as a specific application, we show that the proposed measure can be
used to compare the heterogeneity of recurrence networks constructed from the
time series of several low dimensional chaotic attractors9thereby providing a
single index to compare the structural complexity of chaotic attractors.


title: Public Key Encryption in Non-Abelian Groups

abstract:
  In this paper, we propose a brand new public key encryption scheme in the Lie
group that is a non-abelian group. In particular, we firstly investigate the
intractability assumptions in the Lie group, including the non-abelian
factoring assumption and non-abelian inserting assumption. After that, by using
the FO technique, a CCA secure public key encryption scheme in the Lie group is
proposed. At last, we present the security proof in the random oracle based on
the non-abelian inserting assumption.


title:
Dynamics of open quantum spin systems: An assessment of the quantum
  master equation approach

abstract:
  Data of the numerical solution of the time-dependent Schr\"odinger equation
of a system containing one spin-1/2 particle interacting with a bath of up to
32 spin-1/2 particles is used to construct a Markovian quantum master equation
describing the dynamics of the system spin. The procedure of obtaining this
quantum master equation, which takes the form of a Bloch equation with
time-independent coefficients, accounts for all non-Markovian effects in as
much the general structure of the quantum master equation allows. Our
simulation results show that, with a few rather exotic exceptions, the
Bloch-type equation with time-independent coefficients provides a simple and
accurate description of the dynamics of a spin-1/2 particle in contact with a
thermal bath. A calculation of the coefficients that appear in the Redfield
master equation in the Markovian limit shows that this perturbatively derived
equation quantitatively differs from the numerically estimated Markovian master
equation, the results of which agree very well with the solution of the
time-dependent Schr\"odinger equation.


title: Vulnerable GPU Memory Management: Towards Recovering Raw Data from GPU

abstract:
  In this paper, we present that security threats coming with existing GPU
memory management strategy are overlooked, which opens a back door for
adversaries to freely break the memory isolation: they enable adversaries
without any privilege in a computer to recover the raw memory data left by
previous processes directly. More importantly, such attacks can work on not
only normal multi-user operating systems, but also cloud computing platforms.
  To demonstrate the seriousness of such attacks, we recovered original data
directly from GPU memory residues left by exited commodity applications,
including Google Chrome, Adobe Reader, GIMP, Matlab. The results show that,
because of the vulnerable memory management strategy, commodity applications in
our experiments are all affected.


title:
Spin-Orbit-Induced Spin, Charge, and Energy Transport in Diffusive
  Superconductors

abstract:
  We consider the spin-orbit-induced spin Hall effect and spin swapping in
diffusive superconductors. By employing the non-equilibrium Keldysh Green's
function technique in the quasiclassical approximation, we derive coupled
transport equations for the spectral spin and particle distributions and for
the energy density in the elastic scattering regime. We compute four
contributions to the spin Hall conductivity, namely, skew scattering,
side-jump, anomalous velocity, and the Yafet contribution. The reduced density
of states in the superconductor causes a renormalization of the spin Hall
angle. We demonstrate that all four of these contributions to the spin Hall
conductivity are renormalized in the same way in the superconducting state. In
its simplest manifestation, spin swapping transforms a primary spin current
into a secondary spin current with swapped current and polarization directions.
We find that the spin-swapping coefficient is not explicitly but only
implicitly affected by superconducting correlations through the renormalized
diffusion coefficients. We discuss experimental consequences for measurements
of the (inverse) spin Hall effect and spin swapping in four-terminal
geometries. In our geometry, below the superconducting transition temperature,
the spin-swapping signal is increased an order of magnitude while changes in
the (inverse) spin Hall signal are moderate.


title: Michel parameters in radiative muon decay

abstract:
  Radiative muon and tau lepton decays are described within the
model-independent approach with the help of generalized Michel parameters. The
exact dependence on charged lepton masses is taken into account. The results
are relevant for modern and future experiments on muon and tau lepton decays.


title:
Evaporation Spectrum of Black Holes from a Local Quantum Gravity
  Perspective

abstract:
  We revisit the hypothesis of a possible line structure in the Hawking
evaporation spectrum of black holes. Because of nonperturbative quantum gravity
effects, this would take place arbitrarily far away from the Planck mass. We
show, based on a speculative but consistent hypothesis, that this naive
prediction might in fact hold in the specific context of loop quantum gravity.
A small departure from the ideal case is expected for some low-spin transitions
and could allow us to distinguish several quantum gravity models. We also show
that the effect is not washed out by the dynamics of the process, by existence
of a mass spectrum up to a given width, or by the secondary component induced
by the decay of neutral pions emitted during the time-integrated evaporation.


title:
Molecular shear heating and vortex dynamics in thermostatted
  two-dimensional Yukawa liquids

abstract:
  It is well known that two-dimensional macroscale shear flows are susceptible
to instabilities leading to macroscale vortical structures. The linear and
nonlinear fate of such a macroscale flow in a strongly coupled medium is a
fundamental problem. A popular example of a strongly coupled medium is a dusty
plasma, often modelled as a Yukawa liquid. Recently, laboratory experiments and
MD studies of shear flows in strongly coupled Yukawa liquids, indicated
occurrence of strong molecular shear heating, which is found to reduce the
coupling strength exponentially leading to destruction of macroscale vorticity.
To understand the vortex dynamics of strongly coupled molecular fluids
undergoing macroscale shear flows and molecular shear heating, MD simulation
has been performed, which allows the macroscopic vortex dynamics to evolve
while at the same time, "removes" the microscopically generated heat without
using the velocity degrees of freedom. We demonstrate that by using a
configurational thermostat in a novel way, the microscale heat generated by
shear flow can be thermostatted out efficiently without compromising the large
scale vortex dynamics. In present work, using MD simulations, a comparative
study of shear flow evolution in Yukawa liquids in presence and absence of
molecular or microscopic heating is presented for a prototype shear flow
namely, Kolmogorov flow.


title:
Efficient and Compact Representations of Some Non-Canonical Prefix-Free
  Codes

abstract:
  For many kinds of prefix-free codes there are efficient and compact
alternatives to the traditional tree-based representation. Since these put the
codes into canonical form, however, they can only be used when we can choose
the order in which codewords are assigned to symbols. In this paper we first
show how, given a probability distribution over an alphabet of $\sigma$
symbols, we can store an optimal alphabetic prefix-free code in $\Oh{\sigma
\log L}$ bits such that we can encode and decode any codeword of length $\ell$
in $\Oh{\min (\ell, \log L)}$ time, where $L$ is the maximum codeword length.
With $\Oh{2^{L^\epsilon}}$ further bits, for any constant $\epsilon>0$, we can
encode and decode $\Oh{\log \ell}$ time. We then show how to store a nearly
optimal alphabetic prefix-free code in \(o (\sigma)\) bits such that we can
encode and decode in constant time. We also consider a kind of optimal
prefix-free code introduced recently where the codewords' lengths are
non-decreasing if arranged in lexicographic order of their reverses. We reduce
their storage space to $\Oh{\sigma \log L}$ while maintaining encoding and
decoding times in $\Oh{\ell}$. We also show how, with $\Oh{2^{\epsilon L}}$
further bits, we can encode and decode in constant time. All of our results
hold in the word-RAM model.


title:
Investigation of nulling and subpulse drifting properties of PSR
  J1727$-$2739

abstract:
  Aims. To make a detailed study of the nulling and subpulse drifting in PSR
J1727$-$2739 for investigation of its radiation properties. Methods. The
observations were carried out on 20 March, 2004 using the Parkes 64-m radio
telescope, with a central frequency of 1518 MHz. A total of 5568 single pulses
were analysed. Results. This pulsar shows well defined nulls with lengths
lasting from 6 to 281 pulses and separated by burst phases ranging from 2 to
133 pulses. We estimate a nulling fraction of around 68\%. No emission in the
average pulse profile integrated over all null pulses is detected with
significance above $3\sigma$. Most transitions from nulls to bursts are within
a few pulses, whereas the transitions from bursts to nulls exhibit two patterns
of decay: decrease gradually or rapidly. In the burst phase, we find that there
are two distinct subpulse drift modes with vertical spacing between the drift
bands of $9.7 \pm 1.6$ and $5.2 \pm 0.9$ pulse periods, while sometimes there
is a third mode with no subpulse drifting. Some mode transitions occur within a
single burst, while others are separated by nulls. Different modes have
different average pulse profiles. Possible physical mechanisms are discussed.


title: Global and Local Horizon Quantum Mechanics

abstract:
  Horizons are classical causal structures that arise in systems with sharply
defined energy and corresponding gravitational radius. A global gravitational
radius operator can be introduced for a static and spherically symmetric
quantum mechanical matter state by lifting the classical "Hamiltonian"
constraint that relates the gravitational radius to the ADM mass, thus giving
rise to a "horizon wave-function". This minisuperspace-like formalism is shown
here to be able to consistently describe also the local gravitational radius
related to the Misner-Sharp mass function of the quantum source, provided its
energy spectrum is determine by spatially localised modes.


title:
Large deviations for locally monotone stochastic partial differential
  equations driven by Levy noise

abstract:
  In this paper, we establish a large deviation principle for a type of
stochastic partial differential equations (SPDEs) with locally monotone
coefficients driven by L\'evy noise. The weak convergence method plays an
important role.


title:
Make Workers Work Harder: Decoupled Asynchronous Proximal Stochastic
  Gradient Descent

abstract:
  Asynchronous parallel optimization algorithms for solving large-scale machine
learning problems have drawn significant attention from academia to industry
recently. This paper proposes a novel algorithm, decoupled asynchronous
proximal stochastic gradient descent (DAP-SGD), to minimize an objective
function that is the composite of the average of multiple empirical losses and
a regularization term. Unlike the traditional asynchronous proximal stochastic
gradient descent (TAP-SGD) in which the master carries much of the computation
load, the proposed algorithm off-loads the majority of computation tasks from
the master to workers, and leaves the master to conduct simple addition
operations. This strategy yields an easy-to-parallelize algorithm, whose
performance is justified by theoretical convergence analyses. To be specific,
DAP-SGD achieves an $O(\log T/T)$ rate when the step-size is diminishing and an
ergodic $O(1/\sqrt{T})$ rate when the step-size is constant, where $T$ is the
number of total iterations.


title: Tensor products and the semi-Browder joint spectra

abstract:
  Given two complex Banach spaces $X_1$ and $X_2$, a tensor product of $X_1$
and $X_2$, $X_1\tilde{\otimes}X_2$, in the sense of J. Eschmeier ([5]), and two
finite tuples of commuting operators, $S=(S_1,\ldots ,S_n)$ and $T=(T_1,\ldots
,T_m)$, defined on $X_1$ and $X_2$ respectively, we consider the $(n+m)$-tuple
of operators defined on $X_1\tilde{\otimes}X_2$, $(S\otimes I,I\otimes T)=
(S_1\otimes I,\ldots ,S_n\otimes I,I\otimes T_1,\ldots ,I \otimes T_m)$, and we
give a description of the semi-Browder joint spectra introduced by V. Kordula,
V. M\"uller and V. Rako$\check{c}$evi$\acute{ c}$ in [7] and of the split
semi-Browder joint spectra (see section 3), of the $(n+m)$-tuple $(S\otimes I
,I\otimes T)$, in terms of the corresponding joint spectra of $S$ and $T$. This
result is in some sense a generalization of a formula obtained for other
various Browder spectra in Hilbert spaces and for tensor products of operators
and for tuples of the form $(S\otimes I ,I\otimes T)$. In addition, we also
describe all the mentioned joint spectra for a tuple of left and right
multiplications defined on an operator ideal between Banach spaces in the sense
of [5].


title: Revisiting the theory of ferroelectric negative capacitance

abstract:
  In this paper we revisit the theory of negative capacitance, in a (i)
standalone ferroelectric, (ii) ferroelectric-dielectric, and (iii)
ferroelectric-semiconductor series combination, and show that it is important
to minimize the total Gibbs free energy of the combined system (and not just
the free energy of the ferroelectric) to obtain the correct states. The theory
is explained both analytically and using numerical simulation, for
ferroelectric materials with first order and second order phase transitions.
The exact conditions for different regimes of operation in terms of hysteresis
and gain are derived for ferroelectric-dielectric combination. Finally the
ferroelectric-semiconductor series combination is analyzed to gain insights
into the possibility of realization of steep slope transistors in a hysteresis
free manner.


title: The mode switching of PSR B2020+28

abstract:
  This paper reports on polarimetric radiation properties based on the
switching modes of normal PSR B2020+28 by analysing the data acquired from the
Nanshan 25-m radio telescope at 1556 MHz. With nearly 8 hours quasi-continuous
observation, the data presented some striking and updated phenomena. The change
of relative intensity between the leading and trailing components is the
predominant feature of mode switching. The intensity ratio between the leading
and trailing components are measured for the individual profiles averaged over
30 seconds. It is found that there is an excess of high ratios over the normal
distribution, which indicates that two modes exist in the pulsar. The
distribution of abnormal mode has a narrower width indicating that the abnormal
mode is more stable than the normal mode. A total of 76 mode switching events
are detected in our data. It spends 89\% in the normal mode and 11\% in the
abnormal mode. The intrinsic distributions of mode timescales are constrained
with power-law distributions. The significant difference in the index of the
duration distribution between normal and abnormal modes possibly indicates that
the timescale for the abnormal mode to get stable is shorter than that for the
normal mode. The frequent switching between both modes may indicate that the
oscillations between different magnetospheric states are rapid.


title:
Valley Coherent Hot Carriers and Thermal Relaxation in Monolayer
  Transition Metal Dichalcogenides

abstract:
  We show room temperature valley coherence with in MoS2, MoSe2, WS2 and WSe2
monolayers using linear polarization resolved hot photoluminescence (PL), at
energies close to the excitation - demonstrating preservation of valley
coherence before sufficient scattering events. The features of the co-polarized
hot luminescence allow us to extract the lower bound of the binding energy of
the A exciton in monolayer MoS2 as 0.42 (+/- 0.02) eV. The broadening of the PL
peak is found to be dominated by Boltzmann-type hot luminescence tail, and
using the slope of the exponential decay, the carrier temperature is extracted
in-situ at different stages of energy relaxation. The temperature of the
emitted optical phonons during the relaxation process are probed by exploiting
the corresponding broadening of the Raman peaks due to temperature induced
anharmonic effects. The findings provide a physical picture of photo-generation
of valley coherent hot carriers, and their subsequent energy relaxation path
ways.


title: Green's formulas and variational equations

abstract:
  In this paper, I give an extension to the banachic - non linear- case of the
work of B. Hanouzet and J.L. Joly which is quoted below in the bibliography and
which was elaborated in the hilbertian- linear- case.


title:
Magnetism and Superconductivity in Ferromagnetic Heavy Fermion System
  UCoGe under In-plane Magnetic Fields

abstract:
  We study the ferromagnetic superconductor UCoGe at ambient pressure under
$ab$-plane magnetic fields $\vec{H}$ which are perpendicular to the
ferromagnetic easy axis. It is shown that, by taking into account the
Dyaloshinskii-Moriya interaction arising from the zigzag chain crystal
structure of UCoGe, we can qualitatively explain the experimentally observed
in-plane anisotropy for critical magnetic fields of the paramagnetic
transition. Because of this strong dependence on the magnetic field direction,
upper critical fields of superconductivity, which is mediated by ferromagnetic
spin fluctuations, also become strongly anisotropic. The experimental
observation of "S-shaped" $H_{c2}\parallel b$-axis is qualitatively explained
as a result of enhancement of the spin fluctuations due to decreased Curie
temperature by the $b$-axis magnetic field. We also show that the S-shaped
$H_{c2}$ is accompanied by a rotation of the $d$-vector, which would be a key
to understand the experiments not only at ambient pressure but also under
pressure.


title:
Stability results, almost global generalized Beltrami fields and
  applications to vortex structures in the Euler equations

abstract:
  Strong Beltrami fields have long played a key role in fluid mechanics and
magnetohydrodynamics. In particular, they are the kind of stationary solutions
of the Euler equations where one has been able to show the existence of vortex
structures (vortex tubes and vortex lines) of arbitrarily complicated topology.
On the contrary, there are very few results about the existence of generalized
Beltrami fields, that is, divergence-free fields whose curl is the field itself
times a non-constant function. In fact, generalized Beltrami fields (which are
also stationary solutions to the Euler equations) have been recently shown to
be rare, in the sense that for "most" proportionality factors there are no
nontrivial Beltrami fields of high enough regularity (e.g., of class
$C^{6,\alpha}$), not even locally.
  We show that, nevertheless, there are "many" Beltrami fields with
non-constant factor, even realizing arbitrarily complicated vortex structures.
The core results are an "almost global" stability theorem for strong Beltrami
fields, which ensures that a global strong Beltrami field with suitable decay
at infinity can be perturbed to get "many" Beltrami fields with non-constant
factor of arbitrarily high regularity and defined in the exterior of an
arbitrarily small ball, and a "local" stability theorem for generalized
Beltrami fields, which is an analogous perturbative result that is valid for
any kind of Beltrami field (not just with a constant factor) but only applies
to small enough domains.
  The proof relies on an iterative scheme of Grad-Rubin type. For this purpose,
we study the Neumann problem for the inhomogeneous Beltrami equation in
exterior domains via a boundary integral equation method and we obtain H\"older
estimates, a sharp decay at infinity and some compactness properties for these
sequences of approximate solutions.


title: Evolution of galaxy habitability

abstract:
  We combine a semi-analytic model of galaxy evolution with constraints on
circumstellar habitable zones and the distribution of terrestrial planets to
probe the suitability of galaxies of different mass and type to host habitable
planets, and how it evolves with time. We find that the fraction of stars with
terrestrial planets in their habitable zone (known as habitability) depends
only weakly on galaxy mass, with a maximum around 4e10 Msun. We estimate that
0.7% of all stars in Milky Way type galaxies to host a terrestrial planet
within their habitable zone, consistent with the value derived from Kepler
observations. On the other hand, the habitability of passive galaxies is
slightly but systematically higher, unless we assume an unrealistically high
sensitivity of planets to supernovae. We find that the overall habitability of
galaxies has not changed significantly in the last ~8 Gyr, with most of the
habitable planets in local disk galaxies having formed ~1.5 Gyr before our own
solar system. Finally, we expect that ~1.4e9 planets similar to present-day
Earth have existed so far in our galaxy.


title:
An algorithm to obtain linear determinantal representations of smooth
  plane cubics over finite fields

abstract:
  We give a brief report on our computations of linear determinantal
representations of smooth plane cubics over finite fields. After recalling a
classical interpretation of linear determinantal representations as rational
points on the affine part of Jacobian varieties, we give an algorithm to obtain
all linear determinantal representations up to equivalence. We also report our
recent study on computations of linear determinantal representations of twisted
Fermat cubics defined over the field of rational numbers. This paper is a
summary of the author's talk at the JSIAM JANT workshop on algorithmic number
theory in March, 2016. Details will appear elsewhere.


title:
Positron surface state as a spectroscopic probe for characterizing
  surfaces of topological insulator materials

abstract:
  Topological insulators are attracting considerable interest due to their
potential for technological applications and as platforms for exploring
wide-ranging fundamental science questions. In order to exploit, fine-tune,
control and manipulate the topological surface states, spectroscopic tools
which can effectively probe their properties are of key importance. Here, we
demonstrate that positrons provide a sensitive probe for topological states,
and that the associated annihilation spectrum provides a new technique for
characterizing these states. Firm experimental evidence for the existence of a
positron surface state near Bi$_2$Te$_2$Se with a binding energy of $E_b = 2.7
\pm 0.2 \, \text{eV}$ is presented, and is confirmed by first-principles
calculations. Additionally, the simulations predict a significant signal
originating from annihilation with the topological surface states and shows the
feasibility to detect their spin-texture through the use of spin-polarized
positron beams.


title:
Ripple formation on silver after irradiation with radially polarized
  ultrashort-pulsed lasers

abstract:
  We report on the morphological effects induced by the inhomogeneous
absorption of cylindrically polarized femtosecond laser irradiation of silver
(Ag) in sub-ablation conditions. A theoretical prediction of the role of
surface plasmon excitation in the production of self-formed periodic ripples
structures is evaluated. Furthermore, a combined hydrodynamical and
thermoelastic model is presented to account for the influence of
temperature-related lattice movements in laser beam conditions that are
sufficient to produce material melting. The ability to control the size of the
morphological changes via modulating the beam polarization aims to provide a
systematic methodology for controlling and optimizing the outcome of laser
micro-processing.


title: Analogues of the Ramanujan--Mordell Theorem

abstract:
  The Ramanujan--Mordell Theorem for sums of an even number of squares is
extended to other quadratic forms and quadratic polynomials.


title: Congruences for truncated hypergeometric series ${}_2F_1$

abstract:
  Rodriguez-Villegas conjectured four supercongruences associated to certain
elliptic curves, which were first confirmed by Mortenson by using the
Gross-Koblitz formula. In this paper, we aim to prove four supercongruences
between two truncated hypergeometric series ${}_2F_1$. This generalizes these
four Rodriguez-Villegas supercongruences.


title:
Density shift of Bose gas due to the Casimir effect and mean field
  potential

abstract:
  The shift of density of Bose gas due to the mean field potential (MFP) and
the Casimir effect is systematically investigated in the $d$-dimensional
configuration space from the point of thermodynamic consideration. We show
that, for $d=3$, the shift of density arises completely due to the Casimir
effect and, the MFP remains totally ineffective regardless of the state,
condensate or non-condensate. But for dimension $d>3$ the MFP plays an active
role in shifting the density of Bose gas along with the Casimir interaction.
The sign of density shift becomes positive in the present case. So, the
corresponding critical temperature shift would be negative, because these two
shifts are related as $\Delta n_{c}$/$n_{c}$ $\approx$ -$\Delta T_{c}$/$T_{c}$.
It is important to note that, the MFP causes a shift of density for $d>3$ even
when the Casimir effect is not there, and the sign of shift becomes negative
then; consequently, the critical temperature shift would be positive with MFP
alone in this particular situation.


title: Nodal solutions for Lane-Emden problems in almost-annular domains

abstract:
  In this paper we prove an existence result to the problem
$$\left\{\begin{array}{ll} -\Delta u = |u|^{p-1} u \qquad & \text{in} \Omega,
\\ u= 0 & \text{on} \partial\Omega, \end{array} \right. $$ where $\Omega$ is a
bounded domain in ${\mathbb R}^{N}$ which is a perturbation of the annulus.
Then there exists a sequence $p_1<p_2<..$ with
$\lim\limits_{k\rightarrow+\infty}p_k=+\infty$ such that for any real number
$p>1$ and $p\ne p_k$ there exist at least one solution with $m$ nodal zones.
  In doing so, we also investigate the radial nodal solution in an annulus: we
provide an estimate of its Morse index and analyze the asymptotic behavior as
$p\to 1$.
  Keywords: semilinear elliptic equations, nodal solutions, supercritical
problems.


title: Mirror Reflections of a Black Hole

abstract:
  An exact correspondence between a black hole and an accelerating mirror is
demonstrated. It is shown that for a massless minimally coupled scalar field
the same Bogolubov coefficients connecting the "in" and "out" states occur for
a (1+1)D flat spacetime with a particular perfectly reflecting accelerating
boundary trajectory and a (1+1)D curved spacetime in which a null shell
collapses to form a black hole. Generalization of the latter to the (3+1)D case
is discussed. The spectral dynamics is computed in both (1+1)-dimensional
spacetimes along with the energy flux in the spacetime with a mirror. It is
shown that the approach to equilibrium is monotonic, asymmetric in terms of the
rate, and there is a specific time which characterizes the system when it is
the most out-of-equilibrium.


title: Deep Transfer Learning with Joint Adaptation Networks

abstract:
  Deep networks have been successfully applied to learn transferable features
for adapting models from a source domain to a different target domain. In this
paper, we present joint adaptation networks (JAN), which learn a transfer
network by aligning the joint distributions of multiple domain-specific layers
across domains based on a joint maximum mean discrepancy (JMMD) criterion.
Adversarial training strategy is adopted to maximize JMMD such that the
distributions of the source and target domains are made more distinguishable.
Learning can be performed by stochastic gradient descent with the gradients
computed by back-propagation in linear-time. Experiments testify that our model
yields state of the art results on standard datasets.


title:
Red, Straight, no bends: primordial power spectrum reconstruction from
  CMB and large-scale structure

abstract:
  We present a minimally parametric, model independent reconstruction of the
shape of the primordial power spectrum. Our smoothing spline technique is
well-suited to search for smooth features such as deviations from scale
invariance, and deviations from a power law such as running of the spectral
index or small-scale power suppression. We use a comprehensive set of the
state-of the art cosmological data: {\it Planck} observations of the
temperature and polarisation anisotropies of the cosmic microwave background,
WiggleZ and Sloan Digital Sky Survey Data Release 7 galaxy power spectra and
the Canada-France-Hawaii Lensing Survey correlation function. This
reconstruction strongly supports the evidence for a power law primordial power
spectrum with a red tilt and disfavours deviations from a power law power
spectrum including small-scale power suppression such as that induced by
significantly massive neutrinos. This offers a powerful confirmation of the
inflationary paradigm, justifying the adoption of the inflationary prior in
cosmological analyses.


title: A note on a conjecture of Gy\'arf\'as

abstract:
  This note proves that, given one member, $T$, of a particular family of
radius-three trees, every radius-two, triangle-free graph, $G$, with large
enough chromatic number contains an induced copy of $T$.


title: Decay of correlations for billiards with flat points I: channel effect

abstract:
  In this paper we constructed a special family of semidispersing billiards
bounded on a rectangle with a few dispersing scatters. We assume there exists a
pair of flat points (with zero curvature) on the boundary of these scatters,
whose tangent lines form a channel in the billiard table that is perpendicular
to the vertical sides of the rectangle. The billiard can be induced to a Lorenz
gas with infinite horizon when replacing the rectangle by a torus. We study the
mixing rates of the one-parameter family of the semi-dispersing billiards and
the Lorenz gas on a torus; and show that the correlation functions of both maps
decay polynomially.


title: Programming with a Differentiable Forth Interpreter

abstract:
  Given that in practice training data is scarce for all but a small set of
problems, a core question is how to incorporate prior knowledge into a model.
In this paper, we consider the case of prior procedural knowledge for neural
networks, such as knowing how a program should traverse a sequence, but not
what local actions should be performed at each step. To this end, we present an
end-to-end differentiable interpreter for the programming language Forth which
enables programmers to write program sketches with slots that can be filled
with behaviour trained from program input-output data. We can optimise this
behaviour directly through gradient descent techniques on user-specified
objectives, and also integrate the program into any larger neural computation
graph. We show empirically that our interpreter is able to effectively leverage
different levels of prior program structure and learn complex behaviours such
as sequence sorting and addition. When connected to outputs of an LSTM and
trained jointly, our interpreter achieves state-of-the-art accuracy for
end-to-end reasoning about quantities expressed in natural language stories.


title:
First-order magneto-structural transition in single crystals of the
  honeycomb lattice Ruthenate Li$_{2}$RuO$_3$

abstract:
  Li$_2$RuO$_3$ is known to crystallize in either $C2/m$ or $P2_1/m$ structures
at room temperature. We report the first single crystal growth of Li$_2$RuO$_3$
and Na substituted crystals (Li$_{0.95}$Na$_{0.05}$)$_{2}$RuO$_3$ crystallizing
in the $P2_1/m$ structure where a magneto-structural transition is observed at
high temperatures. Using high temperature ($T \leq 1000$~K) magnetic
susceptibility $\chi$ measurements we study the magnetic anisotropy across the
magneto-structural transition. Our results show for the first time that for
Li$_2$RuO$_3$ the magnetic and structural transitions most likely occur at
slightly different temperatures. The structural transition which is first
order-like occurs first ($T \approx 570$~K) and drives the magnetic transition
($T \approx 540$~K). Rather surprisingly, just $5\%$ Na substitution for Li
affects the magneto-structural transition in an interesting way. The first
order transition temperature stays $\approx 540$~K, the magnetic anisotropy is
reversed, and the Ru-Ru dimerization pattern changes from two short and four
long Ru-Ru bonds per honeycomb in an armchair pattern for Li$_2$RuO$_3$ to four
short and two long bonds per honeycomb in (Li$_{0.95}$Na$_{0.05}$)$_{2}$RuO$_3$
which can be viewed as two inter-penetrating armchair patterns.


title: A Master Space for Moduli Spaces of Gieseker-Stable Sheaves

abstract:
  We consider a notion of stability for sheaves, which we call multi-Gieseker
stability that depends on several ample polarisations $L_1, \dots, L_N$ and on
an additional parameter $\sigma \in \mathbb{Q}_{\geq 0}^N\setminus\{0\}$. The
set of semi stable sheaves admits a projective moduli space $\mathcal
M_{\sigma}$. We prove that given a finite collection of parameters $\sigma$,
there exists a sheaf- and representation-theoretically defined master space $Y$
such that each corresponding moduli space is obtained from $Y$ as a Geometric
Invariant Theory (GIT) quotient. In particular, any two such spaces are related
by a finite number of "Thaddeus-flips". As a corollary, we deduce that any two
Gieseker-moduli space of sheaves (with respect to different polarisations $L_1$
and $L_2$) are related via a GIT-master space. This confirms an old expectation
and generalises results from the surface case to arbitrary dimension.


title:
The emergence of a giant component in random subgraphs of pseudo-random
  graphs

abstract:
  Let $G$ be a $d$-regular graph $G$ on $n$ vertices. Suppose that the
adjacency matrix of $G$ is such that the eigenvalue $\lambda$ which is second
largest in absolute value satisfies $\lambda=o(d)$. Let $G_p$ with
$p=\frac{\alpha}{d}$ be obtained from $G$ by including each edge of $G$
independently with probability $p$. We show that if $\alpha<1$ then whp the
maximum component size of $G_p$ is $O(\log n)$ and if $\alpha>1$ then $G_p$
contains a unique giant component of size $\Omega(n)$, with all other
components of size $O(\log n)$.


title:
Deep convolutional networks on the pitch spiral for musical instrument
  recognition

abstract:
  Musical performance combines a wide range of pitches, nuances, and expressive
techniques. Audio-based classification of musical instruments thus requires to
build signal representations that are invariant to such transformations. This
article investigates the construction of learned convolutional architectures
for instrument recognition, given a limited amount of annotated training data.
In this context, we benchmark three different weight sharing strategies for
deep convolutional networks in the time-frequency domain: temporal kernels;
time-frequency kernels; and a linear combination of time-frequency kernels
which are one octave apart, akin to a Shepard pitch spiral. We provide an
acoustical interpretation of these strategies within the source-filter
framework of quasi-harmonic sounds with a fixed spectral envelope, which are
archetypal of musical notes. The best classification accuracy is obtained by
hybridizing all three convolutional layers into a single deep learning
architecture.


title:
Full-Pose Tracking Control for Aerial Robotic Systems with
  Laterally-Bounded Input Force

abstract:
  In this paper, we define a general class of abstract aerial robotic systems
named Laterally Bounded Force (LBF) vehicles, in which most of the control
authority is expressed along a principal thrust direction, while in the lateral
directions a (smaller and possibly null) force may be exploited to achieve
full-pose tracking. This class approximates well platforms endowed with
non-coplanar/non-collinear rotors that can use the tilted propellers to
slightly change the orientation of the total thrust w.r.t. the body frame. For
this broad class of systems, we introduce a new geometric control strategy in
SE(3) to achieve, whenever made possible by the force constraints, the
independent tracking of position-plus-orientation trajectories. The exponential
tracking of a feasible full-pose reference trajectory is proven using a
Lyapunov technique in SE(3). The method can deal seamlessly with both under-
and fully-actuated LBF platforms. The controller guarantees the tracking of at
least the positional part in the case that an unfeasible full-pose reference
trajectory is provided. The paper provides several experimental tests clearly
showing the practicability of the approach and the sharp improvement with
respect to state of-the-art approaches.


title: Numerical integration of subtraction terms

abstract:
  Numerical approaches to higher-order calculations often employ subtraction
terms, both for the real emission and the virtual corrections. These
subtraction terms have to be added back. In this paper we show that at NLO the
real subtraction terms, the virtual subtraction terms, the integral
representations of the field renormalisation constants and -- in the case of
initial-state partons -- the integral representation for the collinear
counterterm can be grouped together to give finite integrals, which can be
evaluated numerically. This is useful for an extension towards NNLO.


title: Tripartite Version of the Corr\'adi-Hajnal Theorem

abstract:
  Let $G$ be a tripartite graph with $N$ vertices in each vertex class. If each
vertex is adjacent to at least $(2/3)N$ vertices in each of the other classes,
then either $G$ contains a subgraph that consists of $N$ vertex-disjoint
triangles or $G$ is a specific graph in which each vertex is adjacent to
exactly $(2/3)N$ vertices in each of the other classes.


title:
Mott Transitions and Staggered Orders in the Three-component Fermionic
  System: Variational Cluster Approach

abstract:
  The variational cluster approximation is used to study the ground-state
properties and single-particle spectra of the three-component fermionic Hubbard
model defined on the two-dimensional square lattice at half filling. First, we
show that either a paired Mott state or color-selective Mott state is realized
in the paramagnetic system, depending on the anisotropy in the interaction
strengths, except around the SU(3) symmetric point, where a paramagnetic
metallic state is maintained. Then, by introducing Weiss fields to observe
spontaneous symmetry breakings, we show that either a color-density-wave state
or color-selective antiferromagnetic state is realized depending on the
interaction anisotropy and that the first-order phase transition between these
two states occurs at the SU(3) point. We moreover show that these staggered
orders originate from the gain in potential energy (or Slater mechanism) near
the SU(3) point but originate from the gain in kinetic energy (or Mott
mechanism) when the interaction anisotropy is strong. The staggered orders near
the SU(3) point disappear when the next-nearest-neighbor hopping parameters are
introduced, indicating that these orders are fragile, protected only by the
Fermi surface nesting.


title:
Electrically tunable quantum interfaces between photons and spin qubits
  in carbon nanotube quantum dots

abstract:
  We present a new scheme for quantum interfaces to accomplish the
interconversion of photonic qubits and spin qubits based on optomechanical
resonators and the spin-orbit-induced interactions in suspended carbon nanotube
quantum dots. This interface implements quantum spin transducers and further
enables electrical manipulation of local electron spin qubits, which lays the
foundation for all-electrical control of state transfer protocols between two
distant quantum nodes in a quantum network. We numerically evaluate the state
transfer processes and proceed to estimate the effect of each coupling strength
on the operation fidelities.


title: Latent Tree Models for Hierarchical Topic Detection

abstract:
  We present a novel method for hierarchical topic detection where topics are
obtained by clustering documents in multiple ways. Specifically, we model
document collections using a class of graphical models called hierarchical
latent tree models (HLTMs). The variables at the bottom level of an HLTM are
observed binary variables that represent the presence/absence of words in a
document. The variables at other levels are binary latent variables, with those
at the lowest latent level representing word co-occurrence patterns and those
at higher levels representing co-occurrence of patterns at the level below.
Each latent variable gives a soft partition of the documents, and document
clusters in the partitions are interpreted as topics. Latent variables at high
levels of the hierarchy capture long-range word co-occurrence patterns and
hence give thematically more general topics, while those at low levels of the
hierarchy capture short-range word co-occurrence patterns and give thematically
more specific topics. Unlike LDA-based topic models, HLTMs do not refer to a
document generation process and use word variables instead of token variables.
They use a tree structure to model the relationships between topics and words,
which is conducive to the discovery of meaningful topics and topic hierarchies.


title: Gambler's Ruin Bandit Problem

abstract:
  In this paper, we propose a new multi-armed bandit problem called the
Gambler's Ruin Bandit Problem (GRBP). In the GRBP, the learner proceeds in a
sequence of rounds, where each round is a Markov Decision Process (MDP) with
two actions (arms): a continuation action that moves the learner randomly over
the state space around the current state; and a terminal action that moves the
learner directly into one of the two terminal states (goal and dead-end state).
The current round ends when a terminal state is reached, and the learner incurs
a positive reward only when the goal state is reached. The objective of the
learner is to maximize its long-term reward (expected number of times the goal
state is reached), without having any prior knowledge on the state transition
probabilities. We first prove a result on the form of the optimal policy for
the GRBP. Then, we define the regret of the learner with respect to an
omnipotent oracle, which acts optimally in each round, and prove that it
increases logarithmically over rounds. We also identify a condition under which
the learner's regret is bounded. A potential application of the GRBP is optimal
medical treatment assignment, in which the continuation action corresponds to a
conservative treatment and the terminal action corresponds to a risky treatment
such as surgery.


title: Bending the Curve: Improving the ROC Curve Through Error Redistribution

abstract:
  Classification performance is often not uniform over the data. Some areas in
the input space are easier to classify than others. Features that hold
information about the "difficulty" of the data may be non-discriminative and
are therefore disregarded in the classification process. We propose a
meta-learning approach where performance may be improved by post-processing.
This improvement is done by establishing a dynamic threshold on the
base-classifier results. Since the base-classifier is treated as a "black box"
the method presented can be used on any state of the art classifier in order to
try an improve its performance. We focus our attention on how to better control
the true-positive/false-positive trade-off known as the ROC curve. We propose
an algorithm for the derivation of optimal thresholds by redistributing the
error depending on features that hold information about difficulty. We
demonstrate the resulting benefit on both synthetic and real-life data.


title:
Statistical Multiplexing Gain Analysis of Heterogeneous Virtual Base
  Station Pools in Cloud Radio Access Networks

abstract:
  Cloud radio access network (C-RAN) is proposed recently to reduce network
cost, enable cooperative communications, and increase system flexibility
through centralized baseband processing. By pooling multiple virtual base
stations (VBSs) and consolidating their stochastic computational tasks, the
overall computational resource can be reduced, achieving the so-called
statistical multiplexing gain. In this paper, we evaluate the statistical
multiplexing gain of VBS pools using a multi-dimensional Markov model, which
captures the session-level dynamics and the constraints imposed by both radio
and computational resources. Based on this model, we derive a recursive formula
for the blocking probability and also a closed-form approximation for it in
large pools. These formulas are then used to derive the session-level
statistical multiplexing gain of both real-time and delay-tolerant traffic.
Numerical results show that VBS pools can achieve more than 75% of the maximum
pooling gain with 50 VBSs, but further convergence to the upper bound
(large-pool limit) is slow because of the quickly diminishing marginal pooling
gain, which is inversely proportional to a factor between the one-half and
three-fourth power of the pool size. We also find that the pooling gain is more
evident under light traffic load and stringent Quality of Service (QoS)
requirement.


title: Likelihood Gradient Evaluation Using Square-Root Covariance Filters

abstract:
  Using the array form of numerically stable square-root implementation methods
for Kalman filtering formulas, we construct a new square-root algorithm for the
log-likelihood gradient (score) evaluation. This avoids the use of the
conventional Kalman filter with its inherent numerical instabilities and
improves the robustness of computations against roundoff errors. The new
algorithm is developed in terms of covariance quantities and based on the
"condensed form" of the array square-root filter.


title: The Spectral Energy Distribution of the Coldest Known Brown Dwarf

abstract:
  WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known
brown dwarf (~250 K) and the fourth closest known system to the Sun (2.2 pc).
It has been previously detected only in the J band and two mid-IR bands. To
better measure its spectral energy distribution (SED), we have performed deep
imaging of WISE 0855-0714 in six optical and near-IR bands with Gemini
Observatory, the Very Large Telescope, and the Hubble Space Telescope. Five of
the bands show detections, although one detection is marginal (S/N~3). We also
have obtained two epochs of images with the Spitzer Space Telescope for use in
refining the parallax of the brown dwarf. By combining astrometry from this
work and previous studies, we have derived a parallax of 0.449+/-0.008"
(2.23+/-0.04 pc). We have compared our photometry for WISE 0855-0714 to data
for known Y dwarfs and to the predictions of three suites of models by Saumon
et al. (2012) and Morley et al. (2012, 2014) that are defined by the presence
or absence of clouds and non-equilibrium chemistry. Our estimates of Y-J and
J-H for WISE 0855-0714 are redder than colors of other Y dwarfs, confirming a
predicted reversal of near-IR colors to redder values at temperatures below
300-400 K. In color-magnitude diagrams, no single suite of models provides a
clearly superior match to the sequence formed by WISE 0855-0714 and other Y
dwarfs. Instead, the best fitting model changes from one diagram to the next.
Similarly, all of the models have substantial differences from the SED of WISE
0855-0714. As a result, we are currently unable to constrain the presence of
clouds or non-equilibrium chemistry in its atmosphere.


title:
Response of the Unruh-DeWitt detector in flat spacetime with a compact
  dimension

abstract:
  In a flat spacetime with one spatial dimension compactified, inertial
reference frames are not all equivalent, but there are the preferred ones. This
paper investigates the nonequivalence of inertial frames and also that of
uniformly accelerated frames in connection with the response of the
Unruh-DeWitt detector coupled to a massless scalar field. The detector's
transition rates of both excitation and de-excitation are studied in depth for
three different cases: (i) the detector moving at an arbitrary constant
velocity, (ii) moving with a constant acceleration in the compact direction,
and (iii) moving with a constant acceleration in noncompact directions. The
instantaneous transition rate in relation to the switching function is also
taken into account.


title: Note on the universality and the functoriality of the perfect F-locality

abstract:
  In "Frobenius Categories versus Brauer Blocks" we have proved some
universality of the so-called localizing functor associated with a Frobenius
$P$-category $F$, where $P$ is a finite $p$-group, with respect to the coherent
$F$-localities $(\tau,L,\pi)$ such that the contravariant functor $Ker (\pi)$
maps any subgroup of $P$ to an Abelian $p$-group. The purpose of this Note is
both to move from the localizing functor to the perfect locality associated
with $F$ and to remove the Abelian hypothesis in the target. As a consequence,
we get the functoriality for the perfect localities in the strongest form,
improving the Theorem 9.15 in "Existence, uniqueness and functoriality of the
perfect locality over a Frobenius $P$-category".