title:
Directly probing spin dynamics in insulating antiferromagnets using
  ultrashort terahertz pulses

abstract:
  We investigate spin dynamics in the antiferromagnetic (AFM) multiferroic
TbMnO3 using optical- pump, terahertz (THz)-probe spectroscopy. Photoexcitation
results in a broadband THz transmission change, with an onset time of 25 ps at
6 K that becomes faster at higher temperatures. We attribute this time constant
to spin-lattice thermalization. The excellent agreement between our
measurements and previous ultrafast resonant x-ray diffraction measurements on
the same material confirms that our THz pulse directly probes spin order. We
suggest that this could be the case in general for insulating AFM materials, if
the origin of the static absorption in the THz spectral range is magnetic.


title:
Many-soliton bound states in dispersion-managed optical fiber:
  Possibility of fiber-optic transmission of three bits per clock period

abstract:
  We study the stability and the dynamics of many-soliton molecules in
dispersion-managed (DM) optical fibers with focus on five-and seven-soliton
molecules by analytical and numerical means. In particular we calculate the
binding force, pulse durations and equilibrium separations using a variational
approach. Predicted pulse shapes are in good agreement with those found by
numerical simulations of the underlying nonlinear Schr\"odinger equation.
Within limitations soliton molecules with up to seven solitons possibly allow
to encode three bits of data per clock period.


title: A Maximum Principle for Mean-Field SDEs with time change

abstract:
  Time change is a powerful technique for generating noises and providing
flexible models. In the framework of time changed Brownian and Poisson random
measures we study the existence and uniqueness of a solution to a general
mean-field stochastic differential equation. We consider a mean-field
stochastic control problem for mean-field controlled dynamics and we present a
necessary and a sufficient maximum principle. For this we study existence and
uniqueness of solutions to mean-field backward stochastic differential
equations in the context of time change. An example of a centralised control in
an economy with specialised sectors is provided.


title: Inefficient Best Invariant Tests

abstract:
  Test statistics which are invariant under various subgroups of the orthogonal
group are shown to provide tests whose powers are asymptotically equal to their
level against the usual type of contiguous alternative in models where the
number of parameters is allowed to grow as the sample size increases. The
result is applied to the usual analysis of variance test in the Neyman-Scott
many means problem and to an analogous problem in exponential families. Proofs
are based on a method used by Cibisov(1961) to study spacings statistics in a
goodness-of-fit problem. We review the scope of the technique in this context.


title:
A Non-convex One-Pass Framework for Generalized Factorization Machine
  and Rank-One Matrix Sensing

abstract:
  We develop an efficient alternating framework for learning a generalized
version of Factorization Machine (gFM) on steaming data with provable
guarantees. When the instances are sampled from $d$ dimensional random Gaussian
vectors and the target second order coefficient matrix in gFM is of rank $k$,
our algorithm converges linearly, achieves $O(\epsilon)$ recovery error after
retrieving $O(k^{3}d\log(1/\epsilon))$ training instances, consumes $O(kd)$
memory in one-pass of dataset and only requires matrix-vector product
operations in each iteration. The key ingredient of our framework is a
construction of an estimation sequence endowed with a so-called Conditionally
Independent RIP condition (CI-RIP). As special cases of gFM, our framework can
be applied to symmetric or asymmetric rank-one matrix sensing problems, such as
inductive matrix completion and phase retrieval.


title: Photometric and spectroscopic study of the new FUor star V2493 Cyg

abstract:
  The recent results from photometric and spectroscopic study of the FUor star
V2493 Cyg (HBC 722) are presented in the paper. The outburst of V2493 Cyg was
registered during the summer of 2010 before the brightness of the star to reach
the maximum value. V2493 Cyg is the first FUor object, whose outburst was
observed from its very beginning in all spectral ranges. The recent photometric
data show that the star keeps its maximum brightness during the period
September 2013 - May 2016 and the recorded amplitude of the outburst is 5.1
mag. (V) Consequently, the outburst of V2493 Cyg lasts for more than six years.
Our spectral observations showed strong variability in the profiles and
intensity of emission lines especially for H alpha line. We expect that the
interest in this object will increase in the coming years and the results will
help to explore the nature of young stars.


title: OFDM Without CP in Massive MIMO

abstract:
  We study the possibility of removing the cyclic prefix (CP) overhead from
orthogonal frequency division multiplexing (OFDM) in massive multiple-input
multiple-output (MIMO) systems. We consider the uplink transmission while our
results are applicable to the downlink as well. The absence of CP increases the
spectral efficiency in expense of intersymbol interference (ISI) and
intercarrier interference (ICI). It is known that in massive MIMO, the effects
of uncorrelated noise and multiuser interference vanish as the number of base
station (BS) antennas tends to infinity. To investigate if the channel
distortions in the absence of CP fade away, we study the performance of the
standard maximum ratio combining (MRC) receiver. Our analysis reveals that in
this receiver, there always remains some residual interference leading to
saturation of signal-to-interference-plus-noise ratio (SINR). To resolve this
problem, we propose to use the time reversal (TR) technique. Moreover, in order
to further reduce the multiuser interference, we propose a zero-forcing
equalization to be deployed after the TR combining. We compare the achievable
rate of the proposed system with that of the conventional CP-OFDM. We show that
in realistic channels, a higher spectral efficiency is achieved by removing the
CP from OFDM, while reducing the computational complexity.


title: Flavor violating leptonic decays of the Higgs boson

abstract:
  Recent data from the ATLAS and CMS detectors at the Large Hadron Collider at
CERN give a hint of possible violation of flavor in the leptonic decays of the
Higgs boson. In this work we analyze the flavor violating leptonic decays
$H^0_1\to l_i \bar l_j$ ($i\neq j$) within the framework of an MSSM extension
with a vectorlike leptonic generation. Specifically we focus on the decay mode
$H^0_1\to \mu\tau$. The analysis is done including tree and loop contributions
involving exchange of $W, Z$, charge and neutral higgs and leptons and mirror
leptons, charginos and neutralinos and sleptons and mirror sleptons. It is
found that a substantial branching ratio of $H^0_1\to \mu\tau$, i.e., of as
much a ${\cal{O}}(1)\%$, can be achieved in this model, the size hinted by the
ATLAS and CMS data. The flavor violating decays $H^0_1\to e\mu, e\tau$ are also
analyzed and found to be consistent with the current experimental limits. An
analysis of the dependence of flavor violating decays on CP phases is given.
The analysis is extended to include flavor decays of the heavier Higgs bosons.
A confirmation of the flavor violation in Higgs boson decays with more data
that is expected from LHC at $\sqrt s=13$ TeV will be evidence of new physics
beyond the standard model.


title: Strongly dissipative surface diffeomorphisms

abstract:
  We introduce a class of volume-contracting surface diffeomorphisms whose
dynamics is intermediate between one-dimensional dynamics and general surface
dynamics. For that type of systems one can associate to the dynamics a reduced
one-dimensional model and it is proved a type of $C^\infty-$closing lemma on
the support of every ergodic measure. We also show that this class contains
H\'enon maps with Jacobian in $(-1/4,1/4)$.


title:
A streamlined approach to mapping the magnetic induction of skyrmionic
  materials

abstract:
  Recently, Lorentz transmission electron microscopy (LTEM) has helped
researchers advance the emerging field of magnetic skyrmions. These magnetic
quasi-particles, composed of topologically non-trivial magnetization textures,
have a large potential for application as information carriers in low-power
memory and logic devices. LTEM is one of a very few techniques for direct real
space imaging of magnetic features at the nanoscale. For Fresnel-contrast LTEM,
the transport of intensity equation (TIE) is the tool of choice for
quantitative reconstruction of the local magnetic induction through the sample
thickness. Typically this analysis requires collection of at least three
images.Here we show that for uniform thin magnetic films which includes many
skyrmionic samples, the magnetic induction can be quantitatively determined
from a single defocused image using a simplified TIE approach.


title:
A note on Beckett-Gray codes and the relationship of Gray codes to data
  structures

abstract:
  In this paper we introduce a natural mathematical structure derived from
Samuel Beckett's play "Quad". We call this structure a binary Beckett-Gray
code. We enumerate all codes for $n \leq 6$ and give examples for $n=7,8$.
Beckett-Gray codes can be realized as successive states of a queue data
structure. We show that the binary reflected Gray code can be realized as
successive states of two stack data structures.


title: Convergence of Even Simpler Robots without Location Information

abstract:
  The design of distributed gathering and convergence algorithms for tiny
robots has recently received much attention. In particular, it has been shown
that convergence problems can even be solved for very weak, \emph{oblivious}
robots: robots which cannot maintain state from one round to the next. The
oblivious robot model is hence attractive from a self-stabilization
perspective, where state is subject to adversarial manipulation. However, to
the best of our knowledge, all existing robot convergence protocols rely on the
assumption that robots, despite being "weak", can measure distances.
  We in this paper initiate the study of convergence protocols for even simpler
robots, called \emph{monoculus robots}: robots which cannot measure distances.
In particular, we introduce two natural models which relax the assumptions on
the robots' cognitive capabilities: (1) a Locality Detection ($\mathcal{LD}$)
model in which a robot can only detect whether another robot is closer than a
given constant distance or not, (2) an Orthogonal Line Agreement
($\mathcal{OLA}$) model in which robots only agree on a pair of orthogonal
lines (say North-South and West-East, but without knowing which is which).
  The problem turns out to be non-trivial, and simple median and angle
bisection strategies can easily increase the distances among robots (e.g., the
area of the enclosing convex hull) over time. Our main contribution are
deterministic self-stabilizing convergence algorithms for these two models,
together with a complexity analysis. We also show that in some sense, the
assumptions made in our models are minimal: by relaxing the assumptions on the
\textit{monoculus robots} further, we run into impossibility results.


title:
Systematic construction of spin liquids on the square lattice from
  tensor networks with SU(2) symmetry

abstract:
  We elaborate a simple classification scheme of all rank-5 SU(2)-spin
rotational symmetric tensors according to i) the on-site physical spin-$S$,
(ii) the local Hilbert space $V^{\otimes 4}$ of the four virtual (composite)
spins attached to each site and (iii) the irreducible representations of the
$C_{4v}$ point group of the square lattice. We apply our scheme to draw a
complete list of all SU(2)-symmetric translationally and rotationally-invariant
Projected Entangled Pair States (PEPS) with bond dimension $D\leqslant 6$. All
known SU(2)-symmetric PEPS on the square lattice are recovered and simple
generalizations are provided in some cases. More generally, to each of our
symmetry class can be associated a $({\cal D}-1)$-dimensional manifold of spin
liquids (potentially) preserving lattice symmetries and defined in terms of
${\cal D}$ independent tensors of a given bond dimension $D$. In addition,
generic (low-dimensional) families of PEPS explicitly breaking either (i)
particular point-group lattice symmetries (lattice nematics) or (ii) time
reversal symmetry (chiral spin liquids) or (iii) SU(2)-spin rotation symmetry
down to $U(1)$ (spin nematics or N\'eel antiferromagnets) can also be
constructed. We apply this framework to search for new topological chiral spin
liquids characterized by well-defined chiral edge modes, as revealed by their
entanglement spectrum. In particular, we show how the symmetrization of a
double-layer PEPS leads to a chiral topological state with a gapless edge
described by a SU(2)$_2$ Wess-Zumino-Witten model.


title:
The background Friedmannian Hubble constant in relativistic
  inhomogeneous cosmology and the age of the Universe

abstract:
  In relativistic inhomogeneous cosmology, structure formation couples to
average cosmological expansion. A conservative approach to modelling this
assumes an Einstein--de Sitter model (EdS) at early times and extrapolates this
forward in cosmological time as a "background model" against which average
properties of today's Universe can be measured. This requires adopting an
early-epoch--normalised background Hubble constant $H_1^{bg}$. Here, we show
that the $\Lambda$CDM model can be used as an observational proxy to estimate
$H_1^{bg}$ rather than choose it arbitrarily. We assume (i) an EdS model at
early times; (ii) a zero dark energy parameter; (iii) bi-domain scalar
averaging---division of the spatial sections into over- and underdense regions;
and (iv) virialisation (stable clustering) of collapsed regions. We find
$H_1^{bg}= 37.7 \pm 0.4$ km/s/Mpc (random error only) based on a Planck
$\Lambda$CDM observational proxy. Moreover, since the scalar-averaged expansion
rate is expected to exceed the (extrapolated) background expansion rate, the
expected age of the Universe should be much less than $2/(3 H_1^{bg}) = 17.3$
Gyr. The maximum stellar age of Galactic Bulge microlensed low-mass stars (most
likely: 14.7 Gyr; 68\% confidence: 14.0--15.0 Gyr) suggests an age about a Gyr
older than the (no-backreaction) $\Lambda$CDM estimate.


title:
Space-Time Block Diagonalization for Frequency-Selective MIMO Broadcast
  Channels

abstract:
  The most relevant linear precoding method for frequency-flat MIMO broadcast
channels is block diagonalization (BD) which, under certain conditions, attains
the same nonlinear dirty paper coding channel capacity. However, BD is not
easily translated to frequency-selective channels, since space-time information
is required for transceiver design. In this paper, we demonstrate that BD is
feasible in frequency-selective MIMO broadcast channels to eliminate inter-user
interference (IUI) if the transmit block length is sufficiently large, and if
the number of transmit antennas is greater than the number of users. We also
propose three different approaches to mitigate/eliminate inter-symbol
interference (ISI) in block transmissions: i) time-reversal-based BD (TRBD)
which maximizes spatial focusing around the receivers using transmitter
processing only, ii) equalized BD (EBD) which minimizes the ISI using
transmitter processing only, and iii) joint processing BD (JPBD), which uses
linear processing at the transmitter and the receiver to suppress ISI. We
analyze the theoretical diversity and multiplexing gains of these techniques,
and we demonstrate that JPBD approximates full multiplexing gain for a
sufficiently large transmit block length. Extensive numerical simulations show
that the achievable rate and probability of error performance of all the
proposed methods improve those of conventional time-reversal beamforming.
Moreover, JPBD provides the highest achievable rate region for
frequency-selective MIMO broadcast channels.


title:
A preservation theorem for theories without the tree property of the
  first kind

abstract:
  We prove that the NTP$_1$ property of a geometric theory $T$ is inherited by
theories of lovely pairs and $H$-structures associated to $T$. We also provide
a class of examples of nonsimple geometric NTP$_1$ theories.


title: Distributed Probabilistic Bisection Search using Social Learning

abstract:
  We present a novel distributed probabilistic bisection algorithm using social
learning with application to target localization. Each agent in the network
first constructs a query about the target based on its local information and
obtains a noisy response. Agents then perform a Bayesian update of their
beliefs followed by an averaging of the log beliefs over local neighborhoods.
This two stage algorithm consisting of repeated querying and averaging runs
until convergence. We derive bounds on the rate of convergence of the beliefs
at the correct target location. Numerical simulations show that our method
outperforms current state of the art methods.


title:
Geometrically induced reversion of Hall current in a topological
  insulator cavity

abstract:
  An electric charge near the surface of a topological insulator induces an
image magnetic monopole. Here, we show that if the topological insulator
surface has a negative curvature, namely in the case of a semispherical cavity,
the induced Hall current reverses its rotation as the electric charge crosses
the semisphere geometric focus. Such a reversion is shown to be equivalent of
inverting the charge of the image magnetic monopole. We also discuss upon the
case of a semicylindrical cavity, where Hall current reversion appears to be
feasible of probing in realistic experiments.


title: The Random Access Zipper: Simple, Purely-Functional Sequences

abstract:
  We introduce the Random Access Zipper (RAZ), a simple, purely-functional data
structure for editable sequences. A RAZ combines the structure of a zipper with
that of a tree: like a zipper, edits at the cursor require constant time; by
leveraging tree structure, relocating the edit cursor in the sequence requires
logarithmic time. While existing data structures provide these time bounds,
none do so with the same simplicity and brevity of code as the RAZ. The
simplicity of the RAZ provides the opportunity for more programmers to extend
the structure to their own needs, and we provide some suggestions for how to do
so.


title: Feedback-Controlled Sequential Lasso Screening

abstract:
  One way to solve lasso problems when the dictionary does not fit into
available memory is to first screen the dictionary to remove unneeded features.
Prior research has shown that sequential screening methods offer the greatest
promise in this endeavor. Most existing work on sequential screening targets
the context of tuning parameter selection, where one screens and solves a
sequence of $N$ lasso problems with a fixed grid of geometrically spaced
regularization parameters. In contrast, we focus on the scenario where a target
regularization parameter has already been chosen via cross-validated model
selection, and we then need to solve many lasso instances using this fixed
value. In this context, we propose and explore a feedback controlled sequential
screening scheme. Feedback is used at each iteration to select the next problem
to be solved. This allows the sequence of problems to be adapted to the
instance presented and the number of intermediate problems to be automatically
selected. We demonstrate our feedback scheme using several datasets including a
dictionary of approximate size 100,000 by 300,000.


title:
A geometric solution to a maximin problem involving determinants of sets
  of unit vectors in finite dimensional real or complex vector spaces

abstract:
  Given $n+1$ unit vectors in $\mathbf{R}^n$ or $\mathbf{C}^n,$ consider the
absolute values of the determinants of the vectors taken $n$ at a time. By
taking a geometric perspective, we show that the minimum of these determinants
is maximized when the vectors point from the origin to the vertices of a
regular simplex inscribed in the unit sphere in $\mathbf{R}^n,$ even in the
complex case. We also discuss variations on this problem and a few connections
to other problems.


title: A Vision for Online Verification-Validation

abstract:
  Today's programmers face a false choice between creating software that is
extensible and software that is correct. Specifically, dynamic languages permit
software that is richly extensible (via dynamic code loading, dynamic object
extension, and various forms of reflection), and today's programmers exploit
this flexibility to "bring their own language features" to enrich extensible
languages (e.g., by using common JavaScript libraries). Meanwhile, such
library-based language extensions generally lack enforcement of their
abstractions, leading to programming errors that are complex to avoid and
predict.
  To offer verification for this extensible world, we propose online
verification-validation (OVV), which consists of language and VM design that
enables a "phaseless" approach to program analysis, in contrast to the standard
static-dynamic phase distinction. Phaseless analysis freely interposes abstract
interpretation with concrete execution, allowing analyses to use dynamic
(concrete) information to prove universal (abstract) properties about future
execution.
  In this paper, we present a conceptual overview of OVV through a motivating
example program that uses a hypothetical database library. We present a generic
semantics for OVV, and an extension to this semantics that offers a simple
gradual type system for the database library primitives. The result of
instantiating this gradual type system in an OVV setting is a checker that can
progressively type successive continuations of the program until a continuation
is fully verified. To evaluate the proposed vision of OVV for this example, we
implement the VM semantics (in Rust), and show that this design permits
progressive typing in this manner.


title:
Internally $4$-connected binary matroids with every element in three
  triangles

abstract:
  Let $M$ be an internally $4$-connected binary matroid with every element in
three triangles. Then $M$ has at least four elements $e$ such that si$(M/e)$ is
internally 4-connected.


title: The Symmetry of a Simple Optimization Problem in Lasso Screening

abstract:
  Recently dictionary screening has been proposed as an effective way to
improve the computational efficiency of solving the lasso problem, which is one
of the most commonly used method for learning sparse representations. To
address today's ever increasing large dataset, effective screening relies on a
tight region bound on the solution to the dual lasso. Typical region bounds are
in the form of an intersection of a sphere and multiple half spaces. One way to
tighten the region bound is using more half spaces, which however, adds to the
overhead of solving the high dimensional optimization problem in lasso
screening. This paper reveals the interesting property that the optimization
problem only depends on the projection of features onto the subspace spanned by
the normals of the half spaces. This property converts an optimization problem
in high dimension to much lower dimension, and thus sheds light on reducing the
computation overhead of lasso screening based on tighter region bounds.


title: The Energetics of White-light Flares Observed by SDO/HMI and RHESSI

abstract:
  White-light (WL) flares have been observed and studied more than a century
since the first discovery. However, some fundamental physics behind the
brilliant emission remains highly controversial. One of the important facts in
addressing the flare energetics is the spatialtemporal correlation between the
white-light emission and the hard X-ray radiation, presumably suggesting that
the energetic electrons are the energy sources. In this study, we present a
statistical analysis of 25 strong flares (?greater than or equal to M5)
observed simultaneously by the Helioseismic and Magnetic Imager (HMI) on board
the Solar Dynamics Observatory (SDO) and the Reuven Ramaty High Energy Solar
Spectroscopic Imager (RHESSI). Among these events, WL emission was detected by
SDO/HMI in 13 flares, associated with HXR emission. To quantitatively describe
the strength of WL emission, equivalent area (EA) is defined as the integrated
contrast enhancement over the entire flaring area. Our results show that the
equivalent area is inversely proportional to the HXR power index, indicating
that stronger WL emission tends to be associated with larger population of high
energy electrons. However, no obvious correlation is found between WL emission
and flux of non-thermal electrons at 50 keV. For the other group of 13 flares
without detectable WL emission, the HXR spectra are softer (larger power index)
than those flares with WL emission, especially for the X-class flares in this
group.


title: Computing Maximum Flow with Augmenting Electrical Flows

abstract:
  We present an $\tilde{O}\left(m^{\frac{10}{7}}U^{\frac{1}{7}}\right)$-time
algorithm for the maximum $s$-$t$ flow problem and the minimum $s$-$t$ cut
problem in directed graphs with $m$ arcs and largest integer capacity $U$. This
matches the running time of the
$\tilde{O}\left((mU)^{\frac{10}{7}}\right)$-time algorithm of M\k{a}dry (FOCS
2013) in the unit-capacity case, and improves over it, as well as over the
$\tilde{O}\left(m \sqrt{n} \log U\right)$-time algorithm of Lee and Sidford
(FOCS 2014), whenever $U$ is moderately large and the graph is sufficiently
sparse. By well-known reductions, this also gives similar running time
improvements for the maximum-cardinality bipartite $b$-matching problem.
  One of the advantages of our algorithm is that it is significantly simpler
than the ones presented in Madry (FOCS 2013) and Lee and Sidford (FOCS 2014).
In particular, these algorithms employ a sophisticated interior-point method
framework, while our algorithm is cast directly in the classic augmenting path
setting that almost all the combinatorial maximum flow algorithms use. At a
high level, the presented algorithm takes a primal dual approach in which each
iteration uses electrical flows computations both to find an augmenting $s$-$t$
flow in the current residual graph and to update the dual solution. We show
that by maintain certain careful coupling of these primal and dual solutions we
are always guaranteed to make significant progress.


title: On the cone of weighted graphs generated by triangles

abstract:
  Motivated by problems involving triangle-decompositions of graphs, we examine
the facet structure of the cone $\tau_n$ of weighted graphs on $n$ vertices
generated by triangles. Our results include enumeration of facets for small
$n$, a construction producing facets of $\tau_{n+1}$ from facets of $\tau_n$,
and an arithmetic condition on entries of the normal vectors. We also point out
that a copy of $\tau_n$ essentially appears via the perimeter inequalities at
one vertex of the metric polytope.


title: Quark self-energy in an ellipsoidally anisotropic quark-gluon plasma

abstract:
  We calculate the quark self-energy in a quark-gluon plasma that possesses an
ellipsoidal momentum-space anisotropy in the local rest frame. By introducing
additional transverse momentum anisotropy parameters into the parton
distribution functions, we generalize previous results which were obtained for
the case of a spheroidal anisotropy. Our results demonstrate that the presence
of anisotropies in the transverse directions affects the real and imaginary
parts of quark self-energy and, consequently, the self-energy depends on both
the polar and azimuthal angles in the local rest frame of the matter. Our
results for the quark self-energy set the stage for the calculation of the
effects of ellipsoidal momentum-space anisotropy on quark-gluon plasma photon
spectra and collective flow.


title: Domain Separation Networks

abstract:
  The cost of large scale data collection and annotation often makes the
application of machine learning algorithms to new tasks or datasets
prohibitively expensive. One approach circumventing this cost is training
models on synthetic data where annotations are provided automatically. Despite
their appeal, such models often fail to generalize from synthetic to real
images, necessitating domain adaptation algorithms to manipulate these models
before they can be successfully applied. Existing approaches focus either on
mapping representations from one domain to the other, or on learning to extract
features that are invariant to the domain from which they were extracted.
However, by focusing only on creating a mapping or shared representation
between the two domains, they ignore the individual characteristics of each
domain. We suggest that explicitly modeling what is unique to each domain can
improve a model's ability to extract domain-invariant features. Inspired by
work on private-shared component analysis, we explicitly learn to extract image
representations that are partitioned into two subspaces: one component which is
private to each domain and one which is shared across domains. Our model is
trained not only to perform the task we care about in the source domain, but
also to use the partitioned representation to reconstruct the images from both
domains. Our novel architecture results in a model that outperforms the
state-of-the-art on a range of unsupervised domain adaptation scenarios and
additionally produces visualizations of the private and shared representations
enabling interpretation of the domain adaptation process.


title:
Multipliers for von Neumann-Schatten Bessel sequences in separable
  Banach spaces

abstract:
  In this paper we introduce the concept of von Neumann-Schatten Bessel
multipliers and obtain some of their characterizations. Finally, special
attention is devoted to the study of invertible Hilbert--Schmidt frame
multipliers. These results are not only of interest in their own right, but
also they pave the way for obtaining some new results for diagonalization of
matrices in finite dimensional setting as well as for dual $g$-frames. In
particular, we show that a $g$-frame is uniquely determined by the set of its
$g$-frames.


title: Biased Graphs. VI. Synthetic Geometry

abstract:
  A biased graph is a graph with a class of selected circles ("cycles",
"circuits"), called balanced, such that no theta subgraph contains exactly two
balanced circles. A biased graph $\Omega$ has two natural matroids, the frame
matroid $G(\Omega)$, and the lift matroid $L(\Omega)$, and their extensions the
full frame matroid $G^{{}^{{}_{{}_\bullet}}\!}(\Omega)$ and the extended (or
complete) lift matroid $L_0(\Omega)$. In Part IV we used algebra to study the
representations of these matroids by vectors over a skew field and the
corresponding embeddings in Desarguesian projective spaces. Here we redevelop
those representations, independently of Part IV and in greater generality, by
using synthetic geometry.


title: The fluctuations of quadrangular flow

abstract:
  The ATLAS Collaboration has measured for the first time the fourth cumulant
of quadrangular flow, $v_4\{4\}^4$. Unlike the fourth cumulants of elliptic and
triangular flows, it presents a change of sign above 30\% centrality. We show
that this change of sign is predicted by event-by-event hydrodynamics. We argue
that it results from the combined effects of a nonlinear hydrodynamic response,
which couples quadrangular flow to elliptic flow, and elliptic flow
fluctuations.


title: Spin and Valley Control of Free Carriers in Single-Layer WS$_2$

abstract:
  The semiconducting single-layer transition metal dichalcogenides have been
identified as ideal materials for accessing and manipulating spin- and
valley-quantum numbers due to a set of favorable optical selection rules in
these materials. Here, we apply time- and angle-resolved photoemission
spectroscopy to directly probe optically excited free carriers in the
electronic band structure of a high quality single layer of WS$_2$. We observe
that the optically generated free hole density in a single valley can be
increased by a factor of 2 using a circularly polarized optical excitation.
Moreover, we find that by varying the photon energy of the excitation we can
tune the free carrier density in a given spin-split state around the valence
band maximum of the material. The control of the photon energy and polarization
of the excitation thus permits us to selectively excite free electron-hole
pairs with a given spin and within a single valley.


title: Decomposition of Quantum Markov Chains and Its Applications

abstract:
  Markov chains have been widely employed as a fundamental model in the studies
of probabilistic and stochastic communicating and concurrent systems. It is
well-understood that decomposition techniques play a key role in reachability
analysis and model-checking of Markov chains. (Discrete-time) quantum Markov
chains have been introduced as a model of quantum communicating systems [1] and
also a semantic model of quantum programs [2]. The BSCC (Bottom Strongly
Connected Component) and stationary coherence decompositions of quantum Markov
chains were introduced in [3, 4, 5]. This paper presents a new decomposition
technique, namely periodic decomposition, for quantum Markov chains. We further
establish a limit theorem for them. As an application, an algorithm to find a
maximum dimensional noiseless subsystem of a quantum communicating system is
given using decomposition techniques of quantum Markov chains.


title:
Enumerative Properties of Posets Corresponding to a Certain Class of No
  Strategy Games

abstract:
  In this paper, we consider a game beginning with a multiset of elements from
a group. On a move, two elements are replaced by their sum. This is a no
strategy game, and can be modeled as a graded poset with the rank of a node
equal to the cardinality of its multiset. We study the enumerative properties
of certain variations of this game, such as the number of ways to play them and
their numbers of end states. This leads to several new sequences, as well as
new interpretations of classic sequences such as those found in the Catalan and
Motzkin triangles.


title:
Energy Efficient Cooperative Network Coding with Joint Relay Scheduling
  and Power Allocation

abstract:
  The energy efficiency (EE) of a multi-user multi-relay system with the
maximum diversity network coding (MDNC) is studied. We explicitly find the
connection among the outage probability, energy consumption and EE and
formulate the maximizing EE problem under the outage probability constraints.
Relay scheduling (RS) and power allocation (PA) are applied to schedule the
relay states (transmitting, sleeping, \emph{etc}) and optimize the transmitting
power under the practical channel and power consumption models. Since the
optimization problem is NP-hard, to reduce computational complexity, the outage
probability is first tightly approximated to a log-convex form. Further, the EE
is converted into a subtractive form based on the fractional programming. Then
a convex mixed-integer nonlinear problem (MINLP) is eventually obtained. With a
generalized outer approximation (GOA) algorithm, RS and PA are solved in an
iterative manner. The Pareto-optimal curves between the EE and the target
outage probability show the EE gains from PA and RS. Moreover, by comparing
with the no network coding (NoNC) scenario, we conclude that with the same
number of relays, MDNC can lead to EE gains. However, if RS is implemented,
NoNC can outperform MDNC in terms of the EE when more relays are needed in the
MDNC scheme.


title: Surprisal-Driven Feedback in Recurrent Networks

abstract:
  Recurrent neural nets are widely used for predicting temporal data. Their
inherent deep feedforward structure allows learning complex sequential
patterns. It is believed that top-down feedback might be an important missing
ingredient which in theory could help disambiguate similar patterns depending
on broader context. In this paper we introduce surprisal-driven recurrent
networks, which take into account past error information when making new
predictions. This is achieved by continuously monitoring the discrepancy
between most recent predictions and the actual observations. Furthermore, we
show that it outperforms other stochastic and fully deterministic approaches on
enwik8 character level prediction task achieving 1.37 BPC on the test portion
of the text.


title:
Steady States of Infinite-Size Dissipative Quantum Chains via Imaginary
  Time Evolution

abstract:
  Directly in the thermodynamic limit, we show how to combine imaginary and
real time evolution of tensor networks to efficiently and accurately find the
nonequilibrium steady states (NESS) of one-dimensional dissipative quantum
lattices governed by the Lindblad master equation. The imaginary time evolution
first bypasses any highly correlated portions of the real-time evolution
trajectory by directly converging to the weakly correlated subspace of the
NESS, after which real time evolution completes the convergence to the NESS
with high accuracy. We demonstrate the power of the method with the dissipative
transverse field quantum Ising chain. We show that a crossover of an order
parameter shown to be smooth in previous finite-size studies remains smooth in
the thermodynamic limit.


title: Algebraicity of the image of period map

abstract:
  We prove that the image of period map is algebraic, as conjectured by
Griffiths.


title:
Overview of HiFi -- implicit spectral element code framework for
  multi-fluid plasma applications

abstract:
  An overview of the algorithm and a sampling of plasma applications of the
implicit, adaptive high order finite (spectral) element modeling framework,
HiFi, is presented. The distinguishing capabilities of the HiFi code include
adaptive spectral element spatial representation with flexible geometry, highly
parallelizable implicit time advance, and general flux-source form of the
partial differential equations and boundary conditions that can be implemented
in its framework. Early algorithm development and extensive verification
studies of the two-dimensional version of the code, known as SEL, have been
previously described [A.H. Glasser & X.Z. Tang, Comp. Phys. Comm., 164 (2004);
V.S. Lukin, Ph.D. thesis, Princeton University (2008)]. Here, substantial
algorithmic improvements and extensions are presented together with examples of
two- and three- dimensional applications of the HiFi framework. These include a
Cartesian two-dimensional incompressible magnetohydrodynamic simulation of low
dissipation magnetic reconnection in a large system, a two-dimensional
axisymmetric simulation of self-similar compression of a magnetic plasma
confinement configuration, and a three-dimensional Hall MHD simulation of
spheromak tilting and relaxation. Some planned efforts to further improve and
expand the capabilities of the HiFi modeling framework are discussed.


title: Towards Instance Optimal Bounds for Best Arm Identification

abstract:
  In the classical best arm identification (Best-$1$-Arm) problem, we are given
$n$ stochastic bandit arms, each associated with a reward distribution with an
unknown mean. We would like to identify the arm with the largest mean with
probability at least $1-\delta$, using as few samples as possible.
Understanding the sample complexity of Best-$1$-Arm has attracted significant
attention since the last decade. However, the exact sample complexity of the
problem is still unknown.
  Recently, Chen and Li made the gap-entropy conjecture concerning the instance
sample complexity of Best-$1$-Arm. Given an instance $I$, let $\mu_{[i]}$ be
the $i$th largest mean and $\Delta_{[i]}=\mu_{[1]}-\mu_{[i]}$ be the
corresponding gap. $H(I)=\sum_{i=2}^n\Delta_{[i]}^{-2}$ is the complexity of
the instance. The gap-entropy conjecture states that
$\Omega\left(H(I)\cdot\left(\ln\delta^{-1}+\mathsf{Ent}(I)\right)\right)$ is an
instance lower bound, where $\mathsf{Ent}(I)$ is an entropy-like term
determined by the gaps, and there is a $\delta$-correct algorithm for
Best-$1$-Arm with sample complexity
$O\left(H(I)\cdot\left(\ln\delta^{-1}+\mathsf{Ent}(I)\right)+\Delta_{[2]}^{-2}\ln\ln\Delta_{[2]}^{-1}\right)$.
If the conjecture is true, we would have a complete understanding of the
instance-wise sample complexity of Best-$1$-Arm.
  We make significant progress towards the resolution of the gap-entropy
conjecture. For the upper bound, we provide a highly nontrivial algorithm which
requires \[O\left(H(I)\cdot\left(\ln\delta^{-1}
+\mathsf{Ent}(I)\right)+\Delta_{[2]}^{-2}\ln\ln\Delta_{[2]}^{-1}\mathrm{polylog}(n,\delta^{-1})\right)\]
samples in expectation. For the lower bound, we show that for any Gaussian
Best-$1$-Arm instance with gaps of the form $2^{-k}$, any $\delta$-correct
monotone algorithm requires $\Omega\left(H(I)\cdot\left(\ln\delta^{-1} +
\mathsf{Ent}(I)\right)\right)$ samples in expectation.


title: The MacMahon $q$-Catalan is convex

abstract:
  Let $n\geq2$ be an integer. In this paper, we study the convexity of the
so-called MacMahon's $q$-Catalan polynomials $C_n(q)=\frac1{[n+1]_q}\left[ 2n
\atop n \right]_q$ as functions of $q$. Along the way, several intermediate
results on inequalities are presented including a commentary on the convexity
of the generation function for the integer partitions.


title: Deterministic and Fast Randomized Test-and-Set in Optimal Space

abstract:
  The test-and-set object is a fundamental synchronization primitive for shared
memory systems. A test-and-set object stores a bit, initialized to 0, and
supports one operation, test&set(), which sets the bit's value to 1 and returns
its previous value. This paper studies the number of atomic registers required
to implement a test-and-set object in the standard asynchronous shared memory
model with n processes. The best lower bound is log(n)-1 for obstruction-free
(Giakkoupis and Woelfel, 2012) and deadlock-free (Styer and Peterson, 1989)
implementations. Recently a deterministic obstruction-free implementation using
O(sqrt(n)) registers was presented (Giakkoupis, Helmi, Higham, and Woelfel,
2013). This paper closes the gap between these known upper and lower bounds by
presenting a deterministic obstruction-free implementation of a test-and-set
object from Theta(log n) registers of size Theta(log n) bits. We also provide a
technique to transform any deterministic obstruction-free algorithm, in which,
from any configuration, any process can finish if it runs for b steps without
interference, into a randomized wait-free algorithm for the oblivious
adversary, in which the expected step complexity is polynomial in n and b. This
transformation allows us to combine our obstruction-free algorithm with the
randomized test-and-set algorithm by Giakkoupis and Woelfel (2012), to obtain a
randomized wait-free test-and-set algorithm from Theta(log n) registers, with
expected step-complexity Theta(log* n) against the oblivious adversary.


title: Springer correspondence for the split symmetric pair in type $A$

abstract:
  In this paper we establish Springer correspondence for the symmetric pair
$(\mathrm{SL}(N),\mathrm{SO}(N))$ using Fourier transform, parabolic induction
functor, and a nearby cycle sheaves construction due to Grinberg. As
applications, we obtain results on cohomology of Hessenberg varieties and
geometric constructions of irreducible representations of Hecke algebras of
symmetric groups at $q=-1$.


title: Peculiar Magnetism of UAu$_{2}$Si$_{2}$

abstract:
  Single-crystalline UAu$_2$Si$_2$ has been grown by a floating-zone melting
method, and its magnetic, thermal and transport properties have been
investigated through measurements of magnetization, specific heat and
electrical resistivity to reveal its peculiar magnetism. It is shown that
UAu$_2$Si$_2$ undergoes a second-order phase transition at \tm = 19 K, which
had been believed to be ferromagnetic ordering in the literature, from a
paramagnetic phase to an uncompensated antiferromagnetic phase with spontaneous
magnetization along the tetragonal $c$-axis (the easy magnetization direction).
The magnetic entropy analysis points to the itinerant character of 5f electrons
in the magnetic ordered state of UAu$_2$Si$_2$ with large enhancement of the
electronic specific heat coefficient of $\gamma$ $\sim$ 150 mJ/K$^2$mol at 2 K.
It also reveals the relatively isotropic crystalline electric field effect of
this compound, with contrast to the other relative isostructural compounds. The
observed magnetization curves strongly suggest that there is a parasitic
ferromagnetic component developing below $\sim$ 50 K in high coercivity with
the easy axis along the tetragonal $c$-axis. The results are discussed in the
context of evolution of magnetism within the entire family of isostructural
U$T_2$Si$_2$ compounds.


title: Professor Nambu, String Theory and Moonshine Phenomenon

abstract:
  I first recall the last occasion of meeting the late Professor Yoichiro Nambu
in a hospital in Osaka. I then present a brief introduction to the moonshine
phenomenon in string theory which is under recent investigations.


title:
Lets keep it simple, Using simple architectures to outperform deeper and
  more complex architectures

abstract:
  Major winning Convolutional Neural Networks (CNNs), such as AlexNet, VGGNet,
ResNet, GoogleNet, include tens to hundreds of millions of parameters, which
impose considerable computation and memory overhead. This limits their
practical use for training, optimization and memory efficiency. On the
contrary, light-weight architectures, being proposed to address this issue,
mainly suffer from low accuracy. These inefficiencies mostly stem from
following an ad hoc procedure. We propose a simple architecture, called
SimpleNet, based on a set of designing principles, with which we empirically
show, a well-crafted yet simple and reasonably deep architecture can perform on
par with deeper and more complex architectures. SimpleNet provides a good
tradeoff between the computation/memory efficiency and the accuracy. Our simple
13-layer architecture outperforms most of the deeper and complex architectures
to date such as VGGNet, ResNet, and GoogleNet on several well-known benchmarks
while having 2 to 25 times fewer number of parameters and operations. This
makes it very handy for embedded system or system with computational and memory
limitations. We achieved state-of-the-art result on CIFAR10 outperforming
several heavier architectures, near state of the art on MNIST and competitive
results on CIFAR100 and SVHN. Models are made available at:
https://github.com/Coderx7/SimpleNet


title: Charged Particle Monitor on the AstroSat mission

abstract:
  Charged Particle Monitor (CPM) on-board the AstroSat satellite is an
instrument designed to detect the flux of charged particles at the satellite
location. A Cesium Iodide Thallium (CsI(Tl)) crystal is used with a Kapton
window to detect protons with energies greater than 1 MeV. The ground
calibration of CPM was done using gamma-rays from radioactive sources and
protons from particle accelerators. Based on the ground calibration results,
energy deposition above 1 MeV are accepted and particle counts are recorded. It
is found that CPM counts are steady and the signal for the onset and exit of
South Atlantic Anomaly (SAA) region are generated in a very reliable and stable
manner.


title: Computing Zigzag Persistent Cohomology

abstract:
  Zigzag persistent homology is a powerful generalisation of persistent
homology that allows one not only to compute persistence diagrams with less
noise and using less memory, but also to use persistence in new fields of
application. However, due to the increase in complexity of the algebraic
treatment of the theory, most algorithmic results in the field have remained of
theoretical nature.
  This article describes an efficient algorithm to compute zigzag persistence,
emphasising on its practical interest. The algorithm is a zigzag persistent
cohomology algorithm, based on the dualisation of reflections and
transpositions transformations within the zigzag sequence.
  We provide an extensive experimental study of the algorithm. We study the
algorithm along two directions. First, we compare its performance with zigzag
persistent homology algorithm and show the interest of cohomology in zigzag
persistence. Second, we illustrate the interest of zigzag persistence in
topological data analysis by comparing it to state of the art methods in the
field, specifically optimised algorithm for standard persistent homology and
sparse filtrations. We compare the memory and time complexities of the
different algorithms, as well as the quality of the output persistence
diagrams.


title:
Characterizing the solutions to scattering equations that support
  tree-level $\text{N}^{k}\text{MHV}$ gauge/gravity amplitudes

abstract:
  In this paper we define, independent of theories, two discriminant matrices
involving a solution to the scattering equations in four dimensions, the ranks
of which are used to divide the solution set into a disjoint union of subsets.
We further demonstrate, {entirely within the Cachazo-He-Yuan formalism,} that
each subset of solutions gives nonzero contribution to tree-level
$\text{N}^{k}\text{MHV}$ gauge/gravity amplitudes only for a specific value of
$k$. Thus the solutions can be characterized by the rank of their discriminant
matrices, which in turn determines the value of $k$ of the $\text{N}^{k}
\text{MHV}$ amplitudes a solution can support. As another application of the
technique developed, we show analytically that in Einstein-Yang-Mills theory,
if all gluons have the same helicity, the tree-level single-trace amplitudes
must vanish.


title: Hybrid Duplex Switching in Heterogeneous Networks

abstract:
  In this paper, a novel hybrid-duplex scheme based on received power is
proposed for heterogeneous networks (HetNets). In the proposed scheme, the
duplex mode (half- or full-duplex) of each user is switchable according to the
received power from its serving base station (BS). The
signal-to-interference-plus-noise-ratio (SINR) and spectral efficiency are
analyzed for both downlink and uplink channels by using the tools of
\emph{inhomogeneous} Poisson point process. Furthermore, determining power
threshold for duplex mode switching is investigated for sum rate maximization,
which is formulated as a nonlinear integer programming problem and a greedy
algorithm is proposed to solve this problem. The theoretical analysis and the
proposed algorithm are evaluated by numerical simulations. Simulation results
show that the proposed hybrid-duplex scheme outperforms the half-duplex or
full-duplex HetNet schemes.


title:
The Casimir frictional drag force between a SiO2 tip and a
  graphene-covered SiO2 substrate

abstract:
  The possibility of the mechanical detection of the Casimir friction using the
non-contact force microscope is discussed. On a SiO2 tip situated above a
graphene-covered SiO2 substrate will act the frictional drag force mediated by
a fluctuating electromagnetic field produced by a current in the graphene
sheet. This friction force will produce the bending of the cantilever, which
can be measured by state-of-art non-contact force microscope. Both the thermal
and quantum contributions to the Casimir frictional drag force can be studied
using this experimental setup. This result paves the ways for the mechanical
detection of the Casimir friction and for the application of the frictional
drag effect in micro- and nano- electromechanical devices (MEMS and NEMS).


title: Context Gates for Neural Machine Translation

abstract:
  In neural machine translation (NMT), generation of a target word depends on
both source and target contexts. We find that source contexts have a direct
impact on the adequacy of a translation while target contexts affect the
fluency. Intuitively, generation of a content word should rely more on the
source context and generation of a functional word should rely more on the
target context. Due to the lack of effective control over the influence from
source and target contexts, conventional NMT tends to yield fluent but
inadequate translations. To address this problem, we propose context gates
which dynamically control the ratios at which source and target contexts
contribute to the generation of target words. In this way, we can enhance both
the adequacy and fluency of NMT with more careful control of the information
flow from contexts. Experiments show that our approach significantly improves
upon a standard attention-based NMT system by +2.3 BLEU points.


title:
Efficient stopping of current-driven domain wall using a local Rashba
  field

abstract:
  We theoretically show that a locally-embedded Rashba interaction acts as a
strong pinning center for current-driven domain walls and demonstrate efficient
capturing and depinning of the wall using a weak Rashba interaction of the
order of 0.01 eV{\AA}. Our discovery is expected to be useful for the highly
reliable control of domain walls in racetrack memories.


title: Optimal Switching under Ambiguity and Its Applications in Finance

abstract:
  In this paper, we study optimal switching problems under ambiguity. To
characterize the optimal switching under ambiguity in the finite horizon, we
use multidimensional reflected backward stochastic differential equations
(multidimensional RBSDEs) and show that a value function of the optimal
switching under ambiguity coincides with a solutions to multidimensional RBSDEs
with allowing negative switching costs. Furthermore, we naturally extend the
finite horizon problem to the infinite horizon problem. In some applications,
we show that ambiguity affects an optimal switching strategy with the different
way to a usual switching problem without ambiguity.


title:
The complete equivalence canonical form of four matrices over an
  arbitrary division ring

abstract:
  In this paper, we give the complete structures of the equivalence canonical
form of four matrices over an arbitrary division ring. As applications, we
derive some practical necessary and sufficient conditions for the solvability
to some systems of generalized Sylvester matrix equations using the ranks of
their coefficient matrices. The results of this paper are new and available
over the real number field, the complex number field, and the quaternion
algebra.


title:
Entanglement of two hybrid optomechanical cavities composed of BEC atoms
  under Bell detection

abstract:
  In this paper, firstly, we consider bipartite entanglement between each part
of an optomechanical cavity composed of one dimensional Bose-Einstein
condensate (BEC). we investigate atomic collision on the behavior of the BEC in
the week photon-atom coupling constant, and use Bogoliubov approximation for
the BEC. Secondly under above condition, we propose a scheme for entanglement
swapping protocol wich involves tripartite systems. In our investigation, we
consider a scenario where BECs, moving mirrors, and optical cavity modes are
given in a Gaussian state with a covariance matrix (CM). By applying the Bell
measurment to the output optical field modes, we show how the remote
entanglement between two BECs, two moving mirrors, and BEC-mirror modes in
different optomechanical cavity can be generated.


title:
Survey of resampling techniques for improving classification performance
  in unbalanced datasets

abstract:
  A number of classification problems need to deal with data imbalance between
classes. Often it is desired to have a high recall on the minority class while
maintaining a high precision on the majority class. In this paper, we review a
number of resampling techniques proposed in literature to handle unbalanced
datasets and study their effect on classification performance.


title: Local Binary Convolutional Neural Networks

abstract:
  We propose local binary convolution (LBC), an efficient alternative to
convolutional layers in standard convolutional neural networks (CNN). The
design principles of LBC are motivated by local binary patterns (LBP). The LBC
layer comprises of a set of fixed sparse pre-defined binary convolutional
filters that are not updated during the training process, a non-linear
activation function and a set of learnable linear weights. The linear weights
combine the activated filter responses to approximate the corresponding
activated filter responses of a standard convolutional layer. The LBC layer
affords significant parameter savings, 9x to 169x in the number of learnable
parameters compared to a standard convolutional layer. Furthermore, the sparse
and binary nature of the weights also results in up to 9x to 169x savings in
model size compared to a standard convolutional layer. We demonstrate both
theoretically and experimentally that our local binary convolution layer is a
good approximation of a standard convolutional layer. Empirically, CNNs with
LBC layers, called local binary convolutional neural networks (LBCNN), achieves
performance parity with regular CNNs on a range of visual datasets (MNIST,
SVHN, CIFAR-10, and ImageNet) while enjoying significant computational savings.


title:
Limits on gravitational Einstein Equivalence Principle violation from
  monitoring atomic clock frequencies during a year

abstract:
  Sun's gravitation potential at earth varies during a year due to varying
Earth-Sun distance. Comparing the results of very accurate measurements of
atomic clock transitions performed at different time in the year allows us to
study the dependence of the atomic frequencies on the gravitational potential.
We examine the measurement data for the ratio of the frequencies in Hg$^+$ and
Al$^+$ clock transitions and absolute frequency measurements (with respect to
caesium frequency standard) for Dy, Sr, H, hyperfine transitions in Rb and H,
and obtain significantly improved limits on the values of the gravity related
parameter of the Einstein Equivalence Principle violating term in the Standard
Model Extension Hamiltonian $c_{00} = (3.0 \pm 5.7) \times 10^{-7}$ and the
parameter for the gravity-related variation of the fine structure constant
$\kappa_{\alpha} = (-5.3 \pm 10) \times 10^{-8}$.


title: AstroSat - a multi-wavelength astronomy satellite

abstract:
  AstroSat is a multi-wavelength astronomy satellite, launched on 2015
September 28. It carries a suite of scientific instruments for multi-wavelength
observations of astronomical sources. It is a major Indian effort in space
astronomy and the context of AstroSat is examined in a historical perspective.
The Performance Verification phase of AstroSat has been completed and all
instruments are working flawlessly and as planned. Some brief highlights of the
scientific results are also given here.


title: Higher syzygies on abelian surfaces

abstract:
  Based on the theory of an infinitesimal Newton-Okounkov body, we extend the
results of Lazarsfeld-Pareschi-Popa on abelian surfaces. Moreover, we show that
the higher syzygies of $(X,L)$ are completely determined by its Seshadri
constant when $L^{2}$ is large. As an application, we improve the existing
lower bound of $(L^{2})$ for higher syzygies of a polarized abelian surface
$(X,L)$.


title: K-stability of smooth del Pezzo surfaces

abstract:
  In an algebro-geometric way, we completely determine whether smooth del Pezzo
surfaces are K-(semi)stable or not.


title:
PowerWalk: Scalable Personalized PageRank via Random Walks with
  Vertex-Centric Decomposition

abstract:
  Most methods for Personalized PageRank (PPR) precompute and store all
accurate PPR vectors, and at query time, return the ones of interest directly.
However, the storage and computation of all accurate PPR vectors can be
prohibitive for large graphs, especially in caching them in memory for
real-time online querying. In this paper, we propose a distributed framework
that strikes a better balance between offline indexing and online querying. The
offline indexing attains a fingerprint of the PPR vector of each vertex by
performing billions of "short" random walks in parallel across a cluster of
machines. We prove that our indexing method has an exponential convergence,
achieving the same precision with previous methods using a much smaller number
of random walks. At query time, the new PPR vector is composed by a linear
combination of related fingerprints, in a highly efficient vertex-centric
decomposition manner. Interestingly, the resulting PPR vector is much more
accurate than its offline counterpart because it actually uses more random
walks in its estimation. More importantly, we show that such decomposition for
a batch of queries can be very efficiently processed using a shared
decomposition. Our implementation, PowerWalk, takes advantage of advanced
distributed graph engines and it outperforms the state-of-the-art algorithms by
orders of magnitude. Particularly, it responses to tens of thousands of queries
on graphs with billions of edges in just a few seconds.


title:
Charge and orbital order due to cooperative Jahn-Teller effect in
  manganite chains

abstract:
  We derive an effective Hamiltonian that takes into account the quantum nature
of phonons and models cooperative Jahn-Teller effect in the adiabatic regime
and at strong electron-phonon coupling in one dimension. Our approach involves
mapping a strong-coupling problem to a weak-coupling one by using a duality
transformation. Subsequently, a sixth-order perturbation theory is employed in
the polaronic frame of reference where the small parameter is inversely
(directly) proportional to the coupling (adiabaticity). We study charge and
orbital order in ferromagnetic manganite chains and address the pronounced
electron-hole asymmetry in the observed phase diagram. In particular, at strong
coupling, we offer an explanation for the observed density dependence of the
wavevector of charge modulation, i.e., wavevector is proportional to
(independent of) electron density on the electron-doped (hole-doped) side of
the phase diagram of manganites. We also provide a picture for the charge and
orbital order at special fillings $ \frac{1}{2}$, $\frac{1}{3}$, $\frac{1}{4}$,
and $ \frac{1}{5}$; while focusing on the ordering controversy at fillings
$\frac{1}{3}$ and $\frac{1}{4}$, we find that Wigner-crystal arrangement is
preferred over bi-stripe order.


title:
Intrinsic large gap quantum anomalous Hall insulators in La$X$ ($X$=Br,
  Cl, I)

abstract:
  We report a theoretical prediction of a new class of bulk and intrinsic
quantum Anomalous Hall (QAH) insulators La$X$ ($X$=Br, Cl, and I) via
relativistic first-principle calculations. We find that these systems are
innate long-ranged ferromagnets which, with the help of intrinsic spin-orbit
coupling, become QAH insulators. A low-energy multiband tight binding model is
developed to understand the origin of the QAH effect. Finally integer Chern
number is obtained via Berry phase computation for each two-dimensional plane.
These materials have the added benefit of a sizable band gap of as large as
$\sim$ 25 meV, with the flexibility of enhancing it to above 75 meV via strain
engineering. The synthesis of La$X$ materials will provide the impurity-free
single crystals and thin-film QAH insulators for versatile experiments and
functionalities.


title:
MIMO Gaussian Broadcast Channels with Common, Private and Confidential
  Messages

abstract:
  The two-user multiple-input multiple-output (MIMO) Gaussian broadcast channel
(BC) with common, private and confidential messages is considered. The
transmitter sends a common message to both users, a confidential message to
User 1 and a private (non-confidential) message to User 2. The secrecy-capacity
region is characterized by showing that certain inner and outer bounds coincide
and that the boundary points are achieved by Gaussian inputs, which enables the
development of a tight converse. The proof relies on factorization of upper
concave envelopes and a variant of dirty-paper coding (DPC). It is shown that
the entire region is exhausted by using DPC to cancel out the signal of the
non-confidential message at Receiver 1, thus making DPC against the signal of
the confidential message unnecessary. A numerical example illustrates the
secrecy-capacity results.


title:
Self-Optimized Superconductivity Attainable by Interlayer Phase
  Separation at Cuprate Interfaces

abstract:
  Stabilizing superconductivity at high temperatures and elucidating its
mechanism have long been major challenges of materials research in condensed
matter physics. Meanwhile, recent progress in nanostructuring offers
unprecedented possibilities for designing novel functionalities. Above all,
thin films of cuprate and iron-based high-temperature superconductors exhibit
remarkably better superconducting characteristics (e.g. higher critical
temperatures) than in the bulk, but the underlying mechanism is still not
understood. Solving microscopic models suitable for cuprates, here, we
demonstrate that at an interface between a Mott insulator and an overdoped
non-superconducting metal, the superconducting amplitude stays always pinned at
the optimum achieved in the bulk, independently of the carrier concentration in
the metal. This is in contrast to the dome-like dependence in bulk
superconductors, but consistent with the astonishing independence of the
critical temperature from the carrier density x observed at interfaces of
La2CuO4 and La2-xSrxCuO4. We furthermore identify a self-organization mechanism
as responsible for the pinning at the optimum amplitude: An emergent electronic
structure induced by interlayer phase separation eludes bulk phase separation
and inhomogeneities that would kill superconductivity in the bulk. Thus,
interfaces provide an ideal tool to enhance and stabilize superconductivity.
This interfacial example opens up further ways of shaping superconductivity by
suppressing competing instabilities, with direct perspectives for designing
devices.


title: Explicit Serre weights for two-dimensional Galois representations

abstract:
  We prove the explicit version of the Buzzard--Diamond--Jarvis conjecture
formulated by Diamond--Demb\'el\'e--Roberts. More precisely, we prove that it
is equivalent to the original Buzzard--Diamond--Jarvis conjecture, which was
proved for odd primes (under a mild Taylor--Wiles hypothesis) in earlier work
of the third author and coauthors.


title:
Numerical Methods and Comparisons for 1D and Quasi 2D Fluid Streamer
  Propagation Models

abstract:
  In this work, we propose and compare four different strategies to simulate
the fluid model for streamer propagation in one-dimension (1D) and quasi
two-dimension (2D), which consists of a Poisson's equation for particle
velocity and two continuity equations for particle transport. Each strategy
involves of one method for solving Poisson's equation and the other for solving
continuity equations, and a total variation diminishing three-stage Runge-Kutta
method in temporal discretization. The numerical methods for Poisson's equation
include finite volume method, discontinuous Galerkin methods, mixed finite
element method and least-squared finite element method. The numerical method
for continuity equations is chosen from the family of discontinuous Galerkin
methods. The accuracy tests and comparisons show that all of these four
strategies are suitable and competitive in streamer simulations from the
aspects of accuracy and efficiency. Results show these methods are compatible.
By applying any strategy in real simulations, we can study the dynamics of
streamer propagations in both 1D and quasi 2D models.


title:
On the optimal order of integration in Hermite spaces with finite
  smoothness

abstract:
  We study the numerical approximation of integrals over $\mathbb{R}^s$ with
respect to the standard Gaussian measure for integrands which lie in certain
Hermite spaces of functions. The decay rate of the associated sequence is
specified by a single integer parameter which determines the smoothness classes
and the inner product can be expressed via $L_2$ norms of the derivatives of
the function.
  We map higher order digital nets from the unit cube to a suitable subcube of
$\mathbb{R}^s$ via a linear transformation and show that such rules achieve,
apart from powers of $\log N$, the optimal rate of convergence of the
integration error.


title: Remarks on PBW bases of Ringel-Hall algebras of cyclic quivers

abstract:
  In this paper, we give a recursive formula for the interesting PBW basis
$E_{A}$ of composition subalgebras of Ringel-Hall algebras $\fkH_\vartri(n)$ of
cyclic quivers after \cite{DengDuXiao2007generic}, and another construction of
canonical bases of $\U_v^+(\wih{\fks\fkl}_n)$ from the monomial bases $m^{(A)}$
follow \cite{DuZhaomultiplication}. As an application, we will determined all
the canonical basis of $\U_v^+(\wih{\fks\fkl}_2)$ associated with modules of
Lowery length $\leqs3$. Finally, we will discuss the relation of canonical
bases of Ringel-Hall algebras and those of affine quantum Schur algebras.


title:
Affine Geometric Crystal of $A^{(1)}_n$ and Limit of
  Kirillov-Reshetikhin Perfect Crystals

abstract:
  Let $\mathfrak g$ be an affine Lie algebra with index set $I = \{0, 1, 2,
\cdots , n\}$ and ${\mathfrak g}^L$ be its Langlands dual. It is conjectured by
Kashiwara et al.([16]) that for each $k \in I \setminus \{0\}$ the affine Lie
algebra $\mathfrak g$ has a positive geometric crystal whose
ultra-discretization is isomorphic to the limit of certain coherent family of
perfect crystals for ${\mathfrak g}^L$. Motivated by this conjecture we
construct a positive geometric crystal for the affine Lie algebra ${\mathfrak
g}= A^{(1)}_n$ for each Dynkin index $k\in I\setminus\{0\}$ and show that its
ultra-discretization is isomorphic to the limit of a coherent family of perfect
crystals for $A^{(1)}_n$ given by Okado et al.([29]). In the process we develop
and use some lattice-path combinatorics.


title:
Superconductivity and electronic fluctuations in
  Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$ studied by Raman scattering

abstract:
  Using polarization-resolved electronic Raman scattering we study under-doped,
optimally-doped and over-doped Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$ samples in the
normal and superconducting states. We show that low-energy nematic fluctuations
are universal for all studied doping range. In the superconducting state, we
observe two distinct superconducting pair breaking peaks corresponding to one
large and one small superconducting gaps. In addition, we detect a collective
mode below the superconducting transition in the B$_{2g}$ channel and determine
the evolution of its binding energy with doping. Possible scenarios are
proposed to explain the origin of the in-gap collective mode. In the
superconducting state of the under-doped regime, we detect a re-entrance
transition below which the spectral background changes and the collective mode
vanishes.


title: Scaling Laws for Ergodic Spectral Efficiency in MIMO Poisson Networks

abstract:
  In this paper, we examine the benefits of multiple antenna communication in
random wireless networks, the topology of which is modeled by stochastic
geometry. The setting is that of the Poisson bipolar model introduced in [1],
which is a natural model for ad-hoc and device-to-device (D2D) networks. The
primary finding is that, with knowledge of channel state information between a
receiver and its associated transmitter, by zero-forcing successive
interference cancellation, and for appropriate antenna configurations, the
ergodic spectral efficiency can be made to scale linearly with both 1) the
minimum of the number of transmit and receive antennas, 2) the density of nodes
and 3) the path-loss exponent. This linear gain is achieved by using the
transmit antennas to send multiple data streams (e.g. through an open-loop
transmission method) and by exploiting the receive antennas to cancel
interference. Furthermore, when a receiver is able to learn channel state
information from a certain number of near interferers, higher scaling gains can
be achieved when using a successive interference cancellation method. A major
implication of the derived scaling laws is that spatial multiplexing
transmission methods are essential for obtaining better and eventually optimal
scaling laws in multiple antenna random wireless networks. Simulation results
support this analysis.


title:
Electronic Structure of the Kitaev Material $\alpha$-$\textrm{RuCl}_3$
  Probed by Photoemission and Inverse Photoemission Spectroscopies

abstract:
  Recently, $\alpha$-$\textrm{RuCl}_3$ has attracted much attention as a
possible material realization of the honeycomb Kitaev model, which may
stabilize a quantum-spin-liquid state. Compared to extensive studies on its
magnetic properties, there is still a lack of understanding on its electronic
structure, which is strongly related with its Kitaev physics. Here, the
electronic structure of $\alpha$-$\textrm{RuCl}_3$ is investigated by
photoemission (PE) and inverse photoemission (IPE) spectroscopies. The band
gap, directly measured from PE/IPE spectra, is found to be 1.9 eV, much larger
than previous estimations. The LDA calculations show that the on-site Coulomb
interaction $\textit{U}$ can open the band gap without spin-orbit coupling
(SOC). However, the SOC should also be incorporated to reproduce the proper gap
size, indicating that the interplay between $\textit{U}$ and SOC plays an
essential role in the physics of $\alpha$-$\textrm{RuCl}_3$. There exist some
spectral features in PE/IPE spectra which cannot be explained by the LDA
calculations. To explain such discrepancies, we perform the
configuration-interaction calculations for a ${\textrm{RuCl}}_6^{3-}$ cluster.
The experimental data and calculations demonstrate that the 4$\textit{d}$
compound $\alpha$-$\textrm{RuCl}_3$ is a $J_{\textrm{eff}}$ = 1/2 Mott
insulator rather than a quasimolecular-orbital insulator. Our study also
provides important physical parameters, required in verifying the proposed
Kitaev physics in $\alpha$-$\textrm{RuCl}_3$.


title:
Effects of Base-Station Spatial Interdependence on Interference
  Correlation and Network Performance

abstract:
  The spatial-and-temporal correlation of interference has been well studied in
Poisson networks where the interfering base stations (BSs) are independent of
each other. However, there exists spatial interdependence including attraction
and repulsion among the BSs in practical wireless networks, affecting the
interference distribution and hence the network performance. In view of this,
by modeling the network as a Poisson clustered process, we quantify the effects
of spatial interdependence among BSs on the interference correlation and
analytically prove that BS clustering increases the level of interference
correlation. In particular, it is shown that the level increases as the
attraction between the BSs increases. Furthermore, we study the effects of
spatial interdependence among BSs on network performance with a retransmission
scheme via considering heterogeneous cellular networks in which small-cell BSs
exhibit a clustered topology in practice. It is shown that the interference
correlation degrades the network performance and the degradation increases as
the attraction between BSs increases. Finally, a correlation-aware
retransmission scheme is proposed to improve the network performance by taking
advantage of the interference correlation and avoiding the blind
retransmissions.


title: Correlated photon dynamics in dissipative Rydberg media

abstract:
  Rydberg blockade physics in optically dense atomic media under the conditions
of electromagnetically induced transparency (EIT) leads to strong dissipative
interactions between single photons. We introduce a new approach to analyzing
this challenging many-body problem in the limit of large optical depth per
blockade radius. In our approach, we separate the single-polariton EIT physics
from Rydberg-Rydberg interactions in a serialized manner while using a
hard-sphere model for the latter, thus capturing the dualistic particle-wave
nature of light as it manifests itself in dissipative Rydberg-EIT media. Using
this approach, we analyze the saturation behavior of the transmission through
one-dimensional Rydberg-EIT media in the regime of non-perturbative dissipative
interactions relevant to current experiments. Our model is able to capture the
many-body dynamics of bright, coherent pulses through these strongly
interacting media. We compare our model with available experimental data in
this regime and find good agreement. We also analyze a scheme for generating
regular trains of single photons from continuous-wave input and derive its
scaling behavior in the presence of imperfect single-photon EIT.


title: Moduli spaces of Type~$\mathcal{B}$ surfaces with torsion

abstract:
  We examine moduli spaces of locally homogeneous surfaces of
Type~$\mathcal{B}$ with torsion where the symmetric Ricci tensor is
non-degenerate. We also determine the space of affine Killing vector fields in
this context.


title: The Leggett-Garg inequality and Page-Wootters mechanism

abstract:
  Violation of the Leggett-Garg inequality (LGI) implies quantum phenomena. In
this light we establish that the Moreva \textit{et al.} \cite{moreva}
experiment demonstrating the Page-Wootter's mechanism \cite{wootters} falls in
the quantum domain. An observer outside a 2-photons world does not detect any
change in the $2-$photons state,i.e. there is no time parameter for the outside
observer. But an observer attached to one of the photons sees the other photon
evolving and this means there is an "internal" time. The LGI is violated for
the clock photon whose state evolves with the internal time as measured by the
system photon. Conditional probabilities in this 2-photons system are computed
for both sharp and unsharp measurements. The conditional probability increases
for entangled states as obtained by Page and Wootters for both ideal and also
unsharp measurements. We discuss how the conditional probabilities can be used
to distinguish between massless and massive gravitons. This is important in the
context of gravitational waves.


title: Quantum cryptography over non-Markovian channels

abstract:
  A set of schemes for secure quantum communication are analyzed under the
influence of non-Markovian channels. By comparing with the corresponding
Markovian cases, it is seen that the average fidelity in all these schemes can
be maintained for relatively longer periods of time. The effects of
non-Markovian noise on a number of facets of quantum cryptography, such as
quantum secure direct communication, deterministic secure quantum communication
and their controlled counterparts, quantum dialogue, quantum key distribution,
quantum key agreement, etc., have been extensively investigated. Specifically,
a scheme for controlled quantum dialogue (CQD) is analyzed over damping,
dephasing and depolarizing non-Markovian channels, and subsequently, the effect
of these non-Markovian channels on the other schemes of secure quantum
communication is deduced from the results obtained for CQD. The damped
non-Markovian channel causes, a periodic revival in the fidelity; while
fidelity is observed to be sustained under the influence of the dephasing
non-Markovian channel. The depolarizing channel, as well as the other
non-Markovian channels discussed here, show that the obtained average fidelity
subjected to noisy environment depends on the strength of coupling between the
quantum system with its surroundings and the number of rounds of quantum
communication involved in a particular scheme.


title: Uniform Generalization, Concentration, and Adaptive Learning

abstract:
  One fundamental goal in any learning algorithm is to mitigate its risk for
overfitting. Mathematically, this requires that the learning algorithm enjoys a
small generalization risk, which is defined either in expectation or in
probability. Both types of generalization are commonly used in the literature.
For instance, generalization in expectation has been used to analyze
algorithms, such as ridge regression and SGD, whereas generalization in
probability is used in the VC theory, among others. Recently, a third notion of
generalization has been studied, called uniform generalization, which requires
that the generalization risk vanishes uniformly in expectation across all
bounded parametric losses. It has been shown that uniform generalization is, in
fact, equivalent to an information-theoretic stability constraint, and that it
recovers classical results in learning theory. It is achievable under various
settings, such as sample compression schemes, finite hypothesis spaces, finite
domains, and differential privacy. However, the relationship between uniform
generalization and concentration remained unknown. In this paper, we answer
this question by proving that, while a generalization in expectation does not
imply a generalization in probability, a uniform generalization in expectation
does imply concentration. We establish a chain rule for the uniform
generalization risk of the composition of hypotheses and use it to derive a
large deviation bound. Finally, we prove that the bound is tight.


title:
The Study of a Temperature Dependence of the Dark Rate of Single
  Electrons Emitted from a Cathode of a Multi-Cathode Counter as a Method to
  Search for Hidden Photons of CDM

abstract:
  The dark rate of single electrons emitted from a metal cathode of the counter
depends upon a temperature. At cryogenic temperatures the dark rate measured
with bi-alkaline cathodes of PMT has been found to increase by lowering the
temperature of the detector. One of the possible interpretations of this effect
suggests the energy trapping mechanism from the conversion of Hidden Photons of
CDM at the surface of a photocathode. The measurements are planned by using a
Multi-Cathode Counter (MCC) with a copper and aluminum cathodes of 0.2 m2 at
temperatures from 300 K down to 220 K to spot the increase of cryogenic dark
rate from Hidden Photons of CDM. The physical motivation and the description of
the experiment are presented.


title:
Momentum dependence of the imaginary part of the $\omega$- and
  $\eta^\prime$-nucleus optical potential

abstract:
  The photoproduction of $\omega$ and $\eta^\prime$ mesons off carbon and
niobium nuclei has been measured as a function of the meson momentum for
incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The
mesons have been identified via the $\omega \rightarrow \pi^0 \gamma
\rightarrow 3 \gamma$ and $\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6
\gamma$ decays, respectively, registered with the CBELSA/TAPS detector system.
From the measured meson momentum distributions the momentum dependence of the
transparency ratio has been determined for both mesons. Within a Glauber
analysis the in-medium $\omega$ and $\eta^\prime$ widths and the corresponding
absorption cross sections have been deduced as a function of the meson
momentum. The results are compared to recent theoretical predictions for the
in-medium $\omega$ width and $\eta^\prime$-N absorption cross sections. The
energy dependence of the imaginary part of the $\omega$- and
$\eta^\prime$-nucleus optical potential has been extracted. The finer binning
of the present data compared to the existing data allows a more reliable
extrapolation towards the production threshold. The modulus of the imaginary
part of the $\eta^\prime$ nucleus potential is found to be about three times
smaller than recently determined values of the real part of the
$\eta^\prime$-nucleus potential, which makes the $\eta^\prime$ meson a suitable
candidate for the search for meson-nucleus bound states. For the $\omega$
meson, the modulus of the imaginary part near threshold is comparable to the
modulus of the real part of the potential. As a consequence, only broad
structures can be expected which makes the observation of $\omega$ mesic states
very difficult experimentally.


title: Variance-based uncertainty relations for incompatible observables

abstract:
  We formulate uncertainty relations for arbitrary finite number of
incompatible observables. Based on the sum of variances of the observables,
both Heisenberg-type and Schr\"{o}dinger-type uncertainty relations are
provided. These new lower bounds are stronger in most of the cases than the
ones derived from some existing inequalities. Detailed examples are presented.


title:
New economic windows on income and wealth: The k-generalized family of
  distributions

abstract:
  Over the last decades, the distribution of income and wealth has been
deteriorating in many countries, leading to increased inequalities within and
between societies. This tendency has revived the interest in the subject
greatly, yet it still receives very little attention within the realm of
mainstream economic thinking. One reason for this is that the basic paradigm of
"standard economics", the representative-agent General Equilibrium framework,
is badly equipped to cope with distributional issues. Here we argue that when
the economy is treated as a complex system composed of many heterogeneous
interacting agents who give rise to emergent phenomena, to address the main
stylized facts of income/wealth distribution requires leaving the toolbox of
mainstream economics in favour of alternative approaches. The "k-generalized"
family of income/wealth distributions, building on the categories of
complexity, is an example of how advances in the field can be achieved within
new interdisciplinary research contexts.


title: Geometry of generalized amoebas

abstract:
  Recently Krichever proposed a generalization of the amoeba and the Ronkin
function of a plane algebraic curve. In our paper higher-dimensional version of
this generalization is studied. We translate to the generalized case different
geometric results known in the standard amoebas case.


title: Integral laminations on non-orientable surfaces

abstract:
  We describe triangle coordinates for integral laminations on a non-orientable
surface $N_{k,n}$ of genus $k$ with $n$ punctures and one boundary component,
and give an explicit bijection from the set of integral laminations on
$N_{k,n}$ to $(\mathbb{Z}^{2(n+k-2)}\times \mathbb{Z}^k)\setminus
\left\{0\right\}$.


title:
A novel framework for assessing metadata quality in epidemiological and
  public health research settings

abstract:
  Metadata are critical in epidemiological and public health research. However,
a lack of biomedical metadata quality frameworks and limited awareness of the
implications of poor quality metadata renders data analyses problematic. In
this study, we created and evaluated a novel framework to assess metadata
quality of epidemiological and public health research datasets. We performed a
literature review and surveyed stakeholders to enhance our understanding of
biomedical metadata quality assessment. The review identified 11 studies and
nine quality dimensions; none of which were specifically aimed at biomedical
metadata. 96 individuals completed the survey; of those who submitted data,
most only assessed metadata quality sometimes, and eight did not at all. Our
framework has four sections: a) general information; b) tools and technologies;
c) usability; and d) management and curation. We evaluated the framework using
three test cases and sought expert feedback. The framework can assess
biomedical metadata quality systematically and robustly.


title: Worst case QC-MDPC decoder for McEliece cryptosystem

abstract:
  McEliece encryption scheme which enjoys relatively small key sizes as well as
a security reduction to hard problems of coding theory. Furthermore, it remains
secure against a quantum adversary and is very well suited to low cost
implementations on embedded devices.
  Decoding MDPC codes is achieved with the (iterative) bit flipping algorithm,
as for LDPC codes. Variable time decoders might leak some information on the
code structure (that is on the sparse parity check equations) and must be
avoided. A constant time decoder is easy to emulate, but its running time
depends on the worst case rather than on the average case. So far
implementations were focused on minimizing the average cost. We show that the
tuning of the algorithm is not the same to reduce the maximal number of
iterations as for reducing the average cost. This provides some indications on
how to engineer the QC-MDPC-McEliece scheme to resist a timing side-channel
attack.


title:
Well-posedness for the microcurl model in both single and polycrystal
  gradient plasticity

abstract:
  We consider the recently introduced microcurl model which is a variant of
strain gradient plasticity in which the curl of the plastic distortion is
coupled to an additional micromorphic-type field. For both single crystal and
polycrystal cases, we formulate the model and show its well-posedness in the
rate-independent case provided some local hardening (isotropic or linear
kinematic) is taken into account. To this end, we use the functional analytical
framework developed by Han-Reddy. We also compare the model to the relaxed
micromorphic model as well as to a dislocation-based gradient plasticity model.


title: Extension of the Lieb-Schultz-Mattis and Kolb theorem

abstract:
  The theorem of Lieb, Schultz and Mattis (LSM), which states that the S=1/2
XXZ spin chain has gapless or degenerate ground states, can be applied to
broader models. Independently, Kolb considered the relation between the wave
number $q$ and the twisting boundary condition, and he obtained a similar
result as LSM. However, in frustrating cases it is known that there exist
several exceptions for the assumption of the unique lowest state for the finite
size, which is important in the traditional LSM theorem. In our previous paper,
without the assumption of the uniqueness, we have extended the LSMK theorem for
frustrating and non-symmetric cases. However, there remains a complexity in the
proof of continuity. In this paper, we will simplify the proof than the
previous work.


title:
Current dependence of the hot-spot response spectrum of superconducting
  single-photon detectors with different layouts

abstract:
  We show that avoiding bends in a current-carrying superconducting nanowire
enhances the probability for low energy photons to be detected and that this
enhancement is entirely due to the increase in the experimentally achievable
critical current. We studied nanowires shaped as either meander or spiral. The
spirals had different layouts, a double-spiral layout with an S-turn in the
middle and a single-spiral layout without such turn. Nanowires were prepared
from films of niobium nitride with a thickness of 5 nm. For specimens with each
layout we measured the spectra of the single-photon response in the wavelength
range from 400 nm to 1600 nm and defined the cut-off wavelength ${\lambda}c$
beyond which the response rolls off. The largest and the smallest ${\lambda}c$
were found for the single-spiral layout and for the meander, respectively. For
all three layouts the relationship between ${\lambda}c$ and the relative bias
current falls onto a universal curve which has been predicted earlier in the
framework of the modified hot-spot model. For the single-spiral layout, the
efficiency of photon detection at wavelengths smaller than ${\lambda}c$ reaches
the expected absorbance of the spiral structure and the timing jitter per unit
length of the nanowire has the smallest value.


title: Propositional dynamic logic with Belnapian truth values

abstract:
  We introduce BPDL, a combination of propositional dynamic logic PDL with the
basic four-valued modal logic BK studied by Odintsov and Wansing (`Modal logics
with Belnapian truth values', J. Appl. Non-Class. Log. 20, 279--301 (2010)). We
modify the standard arguments based on canonical models and filtration to suit
the four-valued context and prove weak completeness and decidability of BPDL.


title:
Four dimensional quantum oscillator and magnetic-monopole with U(1)
  dynamical group

abstract:
  By using of an appropriate transformation, it was shown that the quantum
system of 4 dimensional simple harmonic oscillator can describe the motion of a
charged particle in the presence of a magnetic monopole field. It was shown
that the Dirac magnetic monopole has the hidden algebra of U(1) symmetry and by
reducing of the dimensions of space, the U(1)*U(1) dynamical group for 4D
harmonic oscillator quantum system was obtained. Using the group representation
and based on explicit solution of the obtained differential equation, the
spectrum of system was calculated.


title: Power of Two as sums of Three Pell Numbers

abstract:
  In this paper, we find all the solutions of the Diophantine equation $P_\ell
+ P_m +P_n=2^a$, in nonnegative integer variables $(n,m,\ell, a)$ where $P_k$
is the $k$-th term of the Pell sequence $\{P_n\}_{n\ge 0}$ given by $P_0=0$,
$P_1=1$ and $P_{n+1}=2P_{n}+ P_{n-1}$ for all $n\geq 1$.


title:
Developing Ecospheres on Transiently Habitable Planets: The Genesis
  Project

abstract:
  It is often presumed, that life evolves relatively fast on planets with
clement conditions, at least in its basic forms, and that extended periods of
habitability are subsequently needed for the evolution of higher life forms.
Many planets are however expected to be only transiently habitable. On a large
set of otherwise suitable planets life will therefore just not have the time to
develop on its own to a complexity level as it did arise on earth with the
cambrian explosion. The equivalent of a cambrian explosion may however have the
chance to unfold on transiently habitable planets if it would be possible to
fast forward evolution by 3-4 billion years (with respect to terrestrial
timescales). We argue here, that this is indeed possible when seeding the
candidate planet with the microbial lifeforms, bacteria and unicellular
eukaryotes alike, characterizing earth before the cambrian explosion. An
interstellar mission of this kind, denoted the `Genesis project', could be
carried out by a relatively low-cost robotic microcraft equipped with a
on-board gene laboratory for the in situ synthesis of the microbes.
  We review here our current understanding of the processes determining the
timescales shaping the geo-evolution of an earth-like planet, the prospect of
finding Genesis candidate planets and selected issues regarding the mission
layout. Discussing the ethical aspects connected with a Genesis mission, which
would be expressively not for human benefit, we will also touch the risk that a
biosphere incompatibility may arise in the wake of an eventual manned
exploration of a second earth.


title:
Triharmonic Riemannian submersions from 3-dimensional manifolds of
  constant curvature

abstract:
  For biharmonic maps, there is a famous conjecture named Chen's conjecture. In
later paper, Wang and Ou gave an affirmative partial answer to submersion
version of Chen's conjecture. In this paper, we give an affirmative partial
answer to submersion version of generalized Chen's conjecture, that is,
triharmonic Riemannian submersions from a 3-dimensional space form into a
surface is harmonic.


title: Modeling of non-rotating neutron stars in minimal dilatonic gravity

abstract:
  The model of minimal dilatonic gravity (MDG), called also the massive
Branse-Dicke model with $\omega =0$, is an alternative model of gravitation,
which uses one Branse-Dicke gravitation-dilaton field $\Phi$ and offers a
simultaneous explanation of the effects of dark energy (DE) and dark matter
(DM). Here we present an extensive research of non-rotating neutron star models
in MDG with four different realistic equations of state (EOS), which are in
agreement with the latest observational data. The equations describing static
spherically symmetric stars in MDG are solved numerically. The effects
corresponding to DE and DM are clearly seen and discussed.


title:
A High Resolution Spectrograph for the 72 cm Waltz Telescope at
  Landessternwarte, Heidelberg

abstract:
  The Waltz Spectrograph is a fiber-fed high-resolution \'echelle spectrograph
for the 72 cm Waltz Telescope at the Landessternwarte, Heidelberg. It uses a
31.6 lines/mm 63.5$^{\circ}$ blaze angle \'echelle grating in white-pupil
configuration, providing a spectral resolving power of $R\sim$65,000 covering
the spectral range between 450$-$800\,nm in one CCD exposure. A prism is used
for cross-dispersion of \'echelle orders. The spectrum is focused by a
commercial apochromat onto a 2k$\times$2k CCD detector with 13.5$\mu$m per
pixel. An exposure meter will be used to obtain precise photon-weighted
midpoints of observations, which will be used in the computation of the
barycentric corrections of measured radial velocities. A stabilized, newly
designed iodine cell is employed for measuring radial velocities with high
precision. Our goal is to reach a radial velocity precision of better than 5
m/s, providing an instrument with sufficient precision and sensitivity for the
discovery of giant exoplanets. Here we describe the design of the Waltz
spectrograph and early on-sky results.


title: On the queue-number of graphs with bounded tree-width

abstract:
  A queue layout of a graph consists of a linear order on the vertices and an
assignment of the edges to queues, such that no two edges in a single queue are
nested. The minimum number of queues needed in a queue layout of a graph is
called its queue-number.
  We show that for each $k\geq1$, graphs with tree-width at most $k$ have
queue-number at most $2^k-1$. This improves upon double exponential upper
bounds due to Dujmovi\'c et al. and Giacomo et al. As a consequence we obtain
that these graphs have track-number at most $2^{O(k^2)}$.
  We complement these results by a construction of $k$-trees that have
queue-number at least $k+1$. Already in the case $k=2$ this is an improvement
to existing results and solves a problem of Rengarajan and Veni Madhavan,
namely, that the maximal queue-number of $2$-trees is equal to $3$.


title: A Toy Penrose Inequality and its Proof

abstract:
  We formulate and prove a toy version of the Penrose inequality. The
formulation mimics the original Penrose inequality in which the scenario is the
following: A shell of null dust collapses in Minkowski space and a marginally
trapped surface forms on it. Through a series of arguments relying on
established assumptions, an inequality relating the area of this surface to the
total energy of the shell is formulated. Then a further reformulation turns the
inequality into a statement relating the area and the outer null expansion of a
class of surfaces in Minkowski space itself. The inequality has been proven to
hold true in many special cases, but there is no proof in general. In the toy
version here presented, an analogous inequality in (2+1)-dimensional anti-de
Sitter space turns out to hold true.