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arxiv_dataset-64001507.02339 | Combined study of $2S$ and $1D$ open-charm mesons with natural
spin-parity
hep-ph hep-ex
In this paper, we perform a combined study of $2S$ and $1D$ open-charm mesons
with natural spin-parity. Our results indicate that
$D^*_1(2600)/D^*_{s1}(2700)$ and $D^*_1(2760)/D^*_{s1}(2860)$ are predominantly
the $2^3S_1$ and $1^3D_1$ charmed/charmed-strange mesons, respectively, while
$D_3^*(2760)/D_{s3}^*(2860)$ can be regarded as the $1^3D_3$
charmed/charmed-strange mesons. In addition, some typical ratios of partial
widths of the discussed natural states are predicted, by which future
experiments can test these assignments, especially for the $2S$-$1D$ mixing
scheme existing in $D^*_1(2600)/D^*_1(2760)$ and
$D^*_{s1}(2700)/D^*_{s1}(2860)$.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-64011507.02439 | Automated Matchmaking to Improve Accuracy of Applicant Selection for
University Education System
cs.AI cs.CY
The accurate applicant selection for university education is imperative to
ensure fairness and optimal use of institutional resources. Although various
approaches are operational in tertiary educational institutions for selecting
applicants, a novel method of automated matchmaking is explored in the current
study. The method functions by matching a prospective students skills profile
to a programmes requisites profile.
Empirical comparisons of the results, calculated by automated matchmaking and
two other selection methods, show matchmaking to be a viable alternative for
accurate selection of applicants. Matchmaking offers a unique advantage that it
neither requires data from other applicants nor compares applicants with each
other. Instead, it emphasises norms that define admissibility to a programme.
We have proposed the use of technology to minimize the gap between students
aspirations, skill sets and course requirements. It is a solution to minimize
the number of students who get frustrated because of mismatched course
selection.
| arxiv topic:cs.AI cs.CY |
arxiv_dataset-64021507.02539 | Distribution of the eigenvalues of a random system of homogeneous
polynomials
math.AG
Let $f=(f_1,\ldots,f_n)$ be a system of $n$ complex homogeneous polynomials
in $n$ variables of degree $d$. We call $\lambda\in\mathbb{C}$ an eigenvalue of
$f$ if there exists $v\in\mathbb{C}^n\backslash\{0\}$ with $f(v)=\lambda v$,
generalizing the case of eigenvalues of matrices ($d=1$). We derive the
distribution of $\lambda$ when the $f_i$ are independently chosen at random
according to the unitary invariant Weyl distribution and determine the limit
distribution for $n\to\infty$.
| arxiv topic:math.AG |
arxiv_dataset-64031507.02639 | Modification by pion exchange of near threshold resonance line shape in
open heavy flavor channel
hep-ph hep-ex
The effect of the pion exchange on the line shape of near threshold
bottomoniumlike resonances decaying into an $S$ wave pair of $B^{(*)}$ mesons
is considered. It is pointed out that this effect, parametrically enhanced by
the heavy meson mass, can be of a practical significance in determining the
parameters of the bottomoniumlike resonances such as the known $Z_b(10610)$ and
$Z_b(10650)$ states.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-64041507.02739 | Design of the Millennium Villages Project Sampling Plan: a simulation
study for a multi-module survey
stat.AP
The Millennium Villages Project (MVP) is a ten-year integrated rural
development project implemented in ten sub-Saharan African sites. At its
conclusion we will conduct an evaluation of its causal effect on a variety of
development outcomes, measured via household surveys in treatment and
comparison areas. Outcomes are measured by six survey modules, with sample
sizes for each demographic group determined by budget, logistics, and the
group's vulnerability. We design a sampling plan that aims to reduce effort for
survey enumerators and maximize precision for all outcomes. We propose
two-stage sampling designs, sampling households at the first stage, followed by
a second stage sample that differs across demographic groups. Two-stage designs
are usually constructed by simple random sampling (SRS) of households and
proportional within-household sampling, or probability proportional to size
sampling (PPS) of households with fixed sampling within each. No measure of
household size is proportional for all demographic groups, putting PPS schemes
at a disadvantage. The SRS schemes have the disadvantage that multiple
individuals sampled per household decreases efficiency due to intra-household
correlation. We conduct a simulation study (using both design- and model-based
survey inference) to understand these tradeoffs and recommend a sampling plan
for the Millennium Villages Project. Similar design issues arise in other
studies with surveys that target different demographic groups.
| arxiv topic:stat.AP |
arxiv_dataset-64051507.02839 | Principle of maximum force and holographic principle: two principles or
one?
gr-qc cs.IT math.IT
We show how the maximum force principle can be derived from the holographic
principle and vice versa, thus demonstrating equivalence of the two principles.
| arxiv topic:gr-qc cs.IT math.IT |
arxiv_dataset-64061507.02939 | Vector variational problem with knitting boundary conditions
math.AP
We consider a variational problem with a polyconvex integrand and nonstandard
boundary conditions that can be treated as minimization of the stress energy
during the suturing process in the plastic surgery. Ex- istence of minimizers
is proved as well as necessary optimality conditions are discussed.
| arxiv topic:math.AP |
arxiv_dataset-64071507.03039 | Block-determinant formalism for an action of a multi-terminal scatterer
cond-mat.mes-hall
The scattering theory of electron transport allows for a compact and powerful
description in terms of $\check{g}^2 = 1$ Green functions, so-called circuit
theory of quantum transport. A scatterer in the theory is characterized by an
action, most generally a Keldysh one, that can be further used as a building
bock of theories describing statistics of electron transport, superconducting
correlations, time-dependent and interaction effects. The action is usually
used in the form suitable for a two-terminal scatterer.
Here we provide a comprehensive derivation of a more general form of the
action that is especially suitable and convenient for general multi-terminal
scatterers. The action is expressed as a determinant of a block of the
scattering matrix obtained by projection on the positive eigenvalues of the
Green functions characterizing the reservoirs. We start with traditional Green
function formalism introducing $\check{g}^2 = 1$ matrices and give a first
example of multi-terminal counting statistics. Further we consider
one-dimensional channels and discuss chiral anomaly arising in this context.
Generalizing on many channels and superconducting situation, we arrive at the
block-determinant relation. We give the necessary elaborative examples
reproducing basic results of counting statistics and super-currents in
multi-terminal junctions.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-64081507.03139 | Freeze-out configuration properties in the 197Au + 197Au reaction at 23
AMeV
nucl-ex
Data from the experiment on the 197Au + 197Au reaction at 23 AMeV are
analyzed with an aim to find signatures of exotic nuclear configurations such
as toroid-shaped objects. The experimental data are compared with predictions
of the ETNA code dedicated to look for such configurations and with the QMD
model. A novel criterion of selecting events possibly resulting from the
formation of exotic freeze-out configurations, "the efficiency factor", is
tested. Comparison between experimental data and model predictions may indicate
for the formation of flat/toroidal nuclear systems.
| arxiv topic:nucl-ex |
arxiv_dataset-64091507.03239 | Assessing the robustness of spatial pattern sequences in a dryland
vegetation model
nlin.PS
A particular sequence of patterns, "$\text{gaps} \to \text{labyrinth} \to
\text{spots}$," occurs with decreasing precipitation in previously reported
numerical simulations of PDE dryland vegetation models. These observations have
led to the suggestion that this sequence of patterns can serve as an early
indicator of desertification in some ecosystems. Since parameter values can
take on a range of plausible values in the vegetation models, it is important
to investigate whether the pattern sequence prediction is robust to variation.
For a particular model, we find that a quantity calculated via
bifurcation-theoretic analysis appears to serve as a proxy for the pattern
sequences that occur in numerical simulations across a range of parameter
values. We find in further analysis that the quantity takes on values
consistent with the standard sequence in an ecologically relevant limit of the
model parameter values. This suggests that the standard sequence is a robust
prediction of the model, and we conclude by proposing a methodology for
assessing the robustness of the standard sequence in other models and
formulations.
| arxiv topic:nlin.PS |
arxiv_dataset-64101507.03339 | Accurate non-covalent interaction energies via an efficient MP2 scaling
procedure
physics.chem-ph cond-mat.mtrl-sci
Using the observed proportionality of CCSD(T) and MP2 correlation interaction
energies [I. Grabowski, E. Fabiano, F. Della Sala, Phys. Chem. Chem. Phys. 15,
15485 (2013)] we propose a simple scaling procedure to compute accurate
interaction energies of non-covalent complexes. Our method makes use of MP2 and
CCSD(T) correlation energies, computed in relatively small basis sets, and
fitted scaling coefficients to yield interaction energies of almost complete
basis set limit CCSD(T) quality. Thanks to the good transferability of the
scaling coefficients involved in the calculations, good results can be easily
obtained for different intermolecular distances.
| arxiv topic:physics.chem-ph cond-mat.mtrl-sci |
arxiv_dataset-64111507.03439 | Polynomial Kernels for Weighted Problems
cs.CC
Kernelization is a formalization of efficient preprocessing for NP-hard
problems using the framework of parameterized complexity. Among open problems
in kernelization it has been asked many times whether there are deterministic
polynomial kernelizations for Subset Sum and Knapsack when parameterized by the
number $n$ of items.
We answer both questions affirmatively by using an algorithm for compressing
numbers due to Frank and Tardos (Combinatorica 1987). This result had been
first used by Marx and V\'egh (ICALP 2013) in the context of kernelization. We
further illustrate its applicability by giving polynomial kernels also for
weighted versions of several well-studied parameterized problems. Furthermore,
when parameterized by the different item sizes we obtain a polynomial
kernelization for Subset Sum and an exponential kernelization for Knapsack.
Finally, we also obtain kernelization results for polynomial integer programs.
| arxiv topic:cs.CC |
arxiv_dataset-64121507.03539 | Beam-Energy Dependence of Charge Balance Functions from Au+Au Collisions
at RHIC
nucl-ex hep-ex nucl-th
Balance functions have been measured in terms of relative pseudorapidity
($\Delta \eta$) for charged particle pairs at the Relativistic Heavy-Ion
Collider (RHIC) from Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 7.7 GeV to 200
GeV using the STAR detector. These results are compared with balance functions
measured at the Large Hadron Collider (LHC) from Pb+Pb collisions at
$\sqrt{s_{\rm NN}}$ = 2.76 TeV by the ALICE Collaboration. The width of the
balance function decreases as the collisions become more central and as the
beam energy is increased. In contrast, the widths of the balance functions
calculated using shuffled events show little dependence on centrality or beam
energy and are larger than the observed widths. Balance function widths
calculated using events generated by UrQMD are wider than the measured widths
in central collisions and show little centrality dependence. The measured
widths of the balance functions in central collisions are consistent with the
delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing
of the balance function in central collisions at $\sqrt{s_{\rm NN}}$ = 7.7 GeV
implies that a QGP is still being created at this relatively low energy.
| arxiv topic:nucl-ex hep-ex nucl-th |
arxiv_dataset-64131507.03639 | Splitting of ISGMR strength in the light-mass nucleus $^{24}$Mg due to
ground-state deformation
nucl-ex nucl-th
The isoscalar giant monopole resonance (ISGMR) strength distribution in
$^{24}$Mg has been determined from background-free inelastic scattering of
386-MeV $\alpha$ particles at extreme forward angles, including 0$^{\circ}$.
The ISGMR strength distribution has been observed for the first time to have a
two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is
explained well by microscopic theory in terms of the prolate deformation of the
ground state of $^{24}$Mg.
| arxiv topic:nucl-ex nucl-th |
arxiv_dataset-64141507.03739 | High cooperativity coupling between a phosphorus donor spin ensemble and
a superconducting microwave resonator
quant-ph cond-mat.mtrl-sci
We investigate the coupling of an ensemble of phosphorus donors in an
isotopically purified $^{28}$Si host lattice interacting with a superconducting
coplanar waveguide resonator. The microwave transmission spectrum of the
resonator shows a normal mode splitting characteristic for high cooperativity.
The evaluated collective coupling strength $g_{\mathrm{eff}}$ is of the same
order as the loss rate of the spin system $\gamma$, indicating the onset of
strong coupling. We develop a statistical model to describe the influence of
temperature on the coupling strength from $50\,\mathrm{mK}$ to
$3.5\,\mathrm{K}$ and find a scaling of the coupling strength with the square
root of the number of thermally polarized spins.
| arxiv topic:quant-ph cond-mat.mtrl-sci |
arxiv_dataset-64151507.03839 | Transmit Power Minimization in Small Cell Networks Under Time Average
QoS Constraints
cs.IT math.IT
We consider a small cell network (SCN) consisting of N cells, with the small
cell base stations (SCBSs) equipped with Nt \geq 1 antennas each, serving K
single antenna user terminals (UTs) per cell. Under this set up, we address the
following question: given certain time average quality of service (QoS) targets
for the UTs, what is the minimum transmit power expenditure with which they can
be met? Our motivation to consider time average QoS constraint comes from the
fact that modern wireless applications such as file sharing, multi-media etc.
allow some flexibility in terms of their delay tolerance. Time average QoS
constraints can lead to greater transmit power savings as compared to
instantaneous QoS constraints since it provides the flexibility to dynamically
allocate resources over the fading channel states. We formulate the problem as
a stochastic optimization problem whose solution is the design of the downlink
beamforming vectors during each time slot. We solve this problem using the
approach of Lyapunov optimization and characterize the performance of the
proposed algorithm. With this algorithm as the reference, we present two main
contributions that incorporate practical design considerations in SCNs. First,
we analyze the impact of delays incurred in information exchange between the
SCBSs. Second, we impose channel state information (CSI) feedback constraints,
and formulate a joint CSI feedback and beamforming strategy. In both cases, we
provide performance bounds of the algorithm in terms of satisfying the QoS
constraints and the time average power expenditure. Our simulation results show
that solving the problem with time average QoS constraints provide greater
savings in the transmit power as compared to the instantaneous QoS constraints.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-64161507.03939 | The role of modeling in troubleshooting: an example from electronics
physics.ed-ph
Troubleshooting systems is integral to experimental physics in both research
and instructional laboratory settings. The recently adopted AAPT Lab Guidelines
identify troubleshooting as an important learning outcome of the undergraduate
laboratory curriculum. We investigate students' model-based reasoning on a
troubleshooting task using data collected in think-aloud interviews during
which pairs of students attempted to diagnose and repair a malfunctioning
circuit. Our analysis scheme is informed by the Experimental Modeling
Framework, which describes physicists' use of mathematical and conceptual
models when reasoning about experimental systems. We show that this framework
is a useful lens through which to characterize the troubleshooting process.
| arxiv topic:physics.ed-ph |
arxiv_dataset-64171507.04039 | Hyper Heterogeneous Cloud-based IMS Software Architecture: A
Proof-of-Concept and Empirical Analysis
cs.DC
The IP Multimedia Subsystem (IMS) defined by the 3GPP has been mainly
developed and deployed by telephony vendors on vendor-specific hardware. Recent
advances in Network Function Virtualisation (NFV) technology paved the way for
virtualized hardware and telephony function elasticity. As such, Telecom
vendors have started to embrace the cloud as a deployment platform, usually
selecting a privileged virtualization platform. Operators would like to deploy
telecom functionality on their already existing IT cloud platforms. Achieving
such flexibility would require the telecom vendors to adopt a software
architecture allowing deployment on many cloud platforms or even heterogeneous
cloud platforms. We propose a distributed software architecture enabling the
deployment of a single software version on multiple cloud platforms thus
allowing for a solution-based deployment. We also present a prototype we
developed to study the characteristics of this architecture.
| arxiv topic:cs.DC |
arxiv_dataset-64181507.04139 | Structural anomalies and short-range magnetic correlations in the
orbitally degenerated system Sr$_2$VO$_4$
cond-mat.str-el
We report on the electronic ground state of a layered perovskite vanadium
oxide Sr$_2$VO$_4$ studied by the combined use of synchrotron radiation x-ray
diffraction (SR-XRD) and muon spin rotation/relaxation ($\mu$SR) techniques,
where $\mu$SR measurements were extended down to 30 mK. We found an
intermediate orthorhombic phase between $T_{\rm c2} \sim$~130 K and $T_{\rm c1}
\sim$~100 K, whereas a tetragonal phase appears for $T > T_{\rm c2}$ and $T <
T_{\rm c1}$. The absence of long-range magnetic order was confirmed by $\mu$SR
at the reentrant tetragonal phase below $T_{\rm c1}$, where the relative
enhancement in the $c$-axis length versus that of the $a$-axis length was
observed. However, no clear indication of the lowering of the tetragonal
lattice symmetry with superlattice modulation, which is expected in the orbital
order state with superstructure of $d_{yz}$ and $d_{zx}$ orbitals, was observed
by SR-XRD below $T_{\rm c1}$. Instead, it was inferred from $\mu$SR that a
magnetic state developed below $T_{\rm c0} \sim$~10 K, which was characterized
by the highly inhomogeneous and fluctuating local magnetic fields down to 30
mK. We argue that the anomalous magnetic ground state below $T_{\rm c0}$
originates from the coexistence of ferromagnetic and antiferromagnetic
correlations.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-64191507.04239 | Puzzles of eta-deformed AdS_5 x S^5
hep-th
We derive the part of the Lagrangian for the sigma model on the eta-deformed
AdS_5 x S^5 space which is quadratic in fermions and has the full dependence on
bosons. We then show that there exists a field redefinition which brings the
corresponding Lagrangian to the standard form of type IIB Green-Schwarz
superstring. Reading off the corresponding RR couplings, we observe that they
fail to satisfy the supergravity equations of motion, despite the presence of
kappa-symmetry. However, in a special scaling limit our solution reproduces the
supergravity background found by Maldacena and Russo. Further, using the
fermionic Lagrangian, we compute a number of new matrix elements of the tree
level world-sheet scattering matrix. We then show that after a unitary
transformation on the basis of two-particle states which is not one-particle
factorisable, the corresponding T-matrix factorises into two equivalent parts.
Each part satisfies the classical Yang-Baxter equation and coincides with the
large tension limit of the q-deformed S-matrix.
| arxiv topic:hep-th |
arxiv_dataset-64201507.04339 | Infinitesimal Newton-Okounkov bodies and jet separation
math.AG
In this paper we explore the connection between asymptotic base loci and
Newton-Okounkov bodies associated to infinitesimal flags. Analogously to the
surface case, we obtain complete characterizations of augmented and restricted
base loci. Interestingly enough, an integral part of the argument is a study of
the relationship between certain simplices contained in Newton-Okoukov bodies
and jet separation; our results also lead to a convex geometric description of
moving Seshadri constants.
| arxiv topic:math.AG |
arxiv_dataset-64211507.04439 | Discovery of Massive, Mostly Star-formation Quenched Galaxies with
Extremely Large Lyman-alpha Equivalent Widths at z ~ 3
astro-ph.GA
We report a discovery of 6 massive galaxies with both extremely large Lya
equivalent width and evolved stellar population at z ~ 3. These MAssive
Extremely STrong Lya emitting Objects (MAESTLOs) have been discovered in our
large-volume systematic survey for strong Lya emitters (LAEs) with twelve
optical intermediate-band data taken with Subaru/Suprime-Cam in the COSMOS
field. Based on the SED fitting analysis for these LAEs, it is found that these
MAESTLOs have (1) large rest-frame equivalent width of EW_0(Lya) ~ 100--300 A,
(2) M_star ~ 10^10.5--10^11.1 M_sun, and (3) relatively low specific star
formation rates of SFR/M_star ~ 0.03--1 Gyr^-1. Three of the 6 MAESTLOs have
extended Ly$\alpha$ emission with a radius of several kpc although they show
very compact morphology in the HST/ACS images, which correspond to the
rest-frame UV continuum. Since the MAESTLOs do not show any evidence for AGNs,
the observed extended Lya emission is likely to be caused by star formation
process including the superwind activity. We suggest that this new class of
LAEs, MAESTLOs, provides a missing link from star-forming to passively evolving
galaxies at the peak era of the cosmic star-formation history.
| arxiv topic:astro-ph.GA |
arxiv_dataset-64221507.04539 | On comparison of simulated and observed seismicity
physics.geo-ph
Numerical simulation of seismicity has been successfully developed and used
for the two last decades. Presently, the general theory of modeling and the
progress in computational techniques provide wide options for simulation of
seismic and aseismic events with various source mechanisms accounting for
blocky structure of rock mass, inclusions, faults, cracks, complicated contact
conditions and various mechanical properties of rock. Meanwhile, in practical
applications, the input data are limited and uncertain. The data on observed
seismicity are also often limited with a few parameters, like coordinates and
time. The paper aims to agree the input and output data, used in and provided
by numerical simulations, with uncertain and limited data of direct
observations. For the input parameters, we suggest their minimal set, which
complies with commonly available data. For output seismic parameters, we
distinguish three major groups, which are provided by field observations. The
first group includes the common (minimal) data on distributions of the event
location. These distributions are of special value for improving the input data
on geometrical features of a problem. The second group employs the data
(commonly available, as well) on the event magnitude. These distributions are
of exceptional need for evaluating the risk of strong events. The third group
employs data on the event source mechanism. It is based on the tensor of
seismic moment/potency, provided by advanced mining seismic systems. This group
includes distributions of the geometrical parameters of the event source
(orientation of nodal planes, B, P and T directions). It is especially
important when establishing and using the connection between stresses and
seismicity. The exposition is illustrated by considering an example of
long-wall mining in a coal seam.
| arxiv topic:physics.geo-ph |
arxiv_dataset-64231507.04639 | Quantum reflection of bright solitary matter-waves from a narrow
attractive potential
physics.atom-ph cond-mat.quant-gas quant-ph
We report the observation of quantum reflection from a narrow, attractive,
potential using bright solitary matter-waves formed from a 85Rb Bose-Einstein
condensate. We create narrow potentials using a tightly focused, red-detuned
laser beam, and observe reflection of up to 25% of the atoms, along with the
trapping of atoms at the position of the beam. We show that the observed
reflected fraction is much larger than theoretical predictions for a narrow
Gaussian potential well; a more detailed model of bright soliton propagation,
accounting for the generic presence of small subsidiary intensity maxima in the
red-detuned beam, suggests that these small intensity maxima are the cause of
this enhanced reflection.
| arxiv topic:physics.atom-ph cond-mat.quant-gas quant-ph |
arxiv_dataset-64241507.04739 | Counting matchings in irregular bipartite graphs and random lifts
math.CO cs.DM math-ph math.MP
We give a sharp lower bound on the number of matchings of a given size in a
bipartite graph. When specialized to regular bipartite graphs, our results
imply Friedland's Lower Matching Conjecture and Schrijver's theorem proven by
Gurvits and Csikvari. Indeed, our work extends the recent work of Csikvari done
for regular and bi-regular bipartite graphs. Moreover, our lower bounds are
order optimal as they are attained for a sequence of $2$-lifts of the original
graph as well as for random $n$-lifts of the original graph when $n$ tends to
infinity.
We then extend our results to permanents and subpermanents sums. For
permanents, we are able to recover the lower bound of Schrijver recently proved
by Gurvits using stable polynomials. Our proof is algorithmic and borrows ideas
from the theory of local weak convergence of graphs, statistical physics and
covers of graphs. We provide new lower bounds for subpermanents sums and obtain
new results on the number of matching in random $n$-lifts with some
implications for the matching measure and the spectral measure of random
$n$-lifts as well as for the spectral measure of infinite trees.
| arxiv topic:math.CO cs.DM math-ph math.MP |
arxiv_dataset-64251507.04839 | Distance-regular graphs with valency k having smallest eigenvalue at
most -k/2
math.CO
In this paper, we study the non-bipartite distance-regular graphs with
valency k and having a smallest eigenvalue at most -k/2.
| arxiv topic:math.CO |
arxiv_dataset-64261507.04939 | Gapped Excitations of unconventional FQHE states in the Second Landau
Level
cond-mat.mes-hall
We report the observation of low-lying collective charge and spin excitations
in the second Landau level at {\nu} = 2 + 1/3 and also for the very fragile
states at {\nu} = 2 + 2/5, 2 + 3/8 in inelastic light scattering experiments.
These modes exhibit a clear dependence on filling factor and temperature
substantiating the unique access to the characteristic neutral excitation
spectra of the incompressible FQHE states. A detailed mode analysis reveals low
energy modes at around 70 {\mu}eV and a sharp mode slightly below the Zeeman
energy interpreted as gap and spin wave excitation, respectively. The lowest
energy collective charge excitation spectrum at {\nu} = 2 + 1/3 exhibits
significant similarities and a universal scaling of the energies with its
cousin state in the lowest Landau level at {\nu} = 1/3 suggesting similar
underlying physics. The observed excitation spectra facilitate to distinguish
between theoretical descriptions of the nature of those FQHE states. A striking
polarization dependence in light scattering is discussed in the framework of
anisotropic electron phases that allow for the stabilization of nematic FQHE
states.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-64271507.05039 | Trial for a proof of the Syracuse conjecture
math.GM
The infamous 3x+1 conjecture spread by Lothar Collatz in 1952, despite its
elementary formulation, remained unproved for over 60 years. From the
heuristical probabilistic approach to the complex mapping of the algorithm, the
scientific community has fetched for many methods to try to prove it formally,
and thus, mathematicians like Erdos tend to believe that "mathematics are not
yet ready for such problems". In this research report, covering domains like
algebra and graph theory, it is shown a trial of proof of the conjecture by
disproval of its two antitheses: the existence of an ever-growing Syracuse
suite and the existence of a cycle different from the cycle 4,2,1.
| arxiv topic:math.GM |
arxiv_dataset-64281507.05139 | On classification of modular categories by rank
math.QA
The feasibility of a classification-by-rank program for modular categories
follows from the Rank-Finiteness Theorem. We develop arithmetic, representation
theoretic and algebraic methods for classifying modular categories by rank. As
an application, we determine all possible fusion rules for all rank=$5$ modular
categories and describe the corresponding monoidal equivalence classes.
| arxiv topic:math.QA |
arxiv_dataset-64291507.05239 | On the Partition Dimension of Circulant Graphs
math.CO
For a vertex $v$ of a connected graph $G(V,E)$ and a subset $S$ of $V$, the
distance between $v$ and $S$ is defined by $d(v,S)=min\{d(v,x):x \in S \}.$ For
an ordered \emph{k}-partition $\Pi=\{S_1,S_2\ldots S_k\}$ of $V$, the
representation of $v$ with respect to $\Pi$ is the $k$-vector $r(v|\Pi)
=(d(v,S_1),d(v,S_2)\ldots d(v,S_k)).$ The $k$-partition $\Pi$ is a resolving
partition if the $k$-vectors $r(v|\Pi)$, $v \in V$ are distinct. The minimum
$k$ for which there is a resolving $k$-partition of $V$ is the \emph{partition
dimension} of $G$. Salman et al.{\rm\cite{SaJaCh12}} claimed that
\emph{partition dimension} of a class of circulant graphs $C(n,\pm \{1,2\})$,
for all even $n\geq6$ is 4 and it is 3 when $n$ is odd. In this paper we obtain
the partition dimension of circulant graphs $G=C(n, \pm \{1,2 \ldots j\}),
1\leq j < \lfloor \frac{n}{2}\rfloor$, $n \geq(j+k)(j+1)$, $n \equiv \ k \ mod
\ (2j)$ and $k$ and $2j$ are co-primes as, \begin{eqnarray*} pd(G) &=& j+1 \ \
\ \ \ \ \ when \ j \ \ is \ even \ and\ all \ k=2m-1, 1 \leq m \leq j \\
pd(G)&=& j+1\ \ \ \ \ \ \ when \ j \ \ is \ odd \ and\ all \ k=2m, 1 \leq m
\leq j. \end{eqnarray*}
| arxiv topic:math.CO |
arxiv_dataset-64301507.05339 | Path-integral Evidence
astro-ph.CO
Here we present a Bayesian formalism for the goodness-of-fit that is the
evidence for a fixed functional form over the evidence for all functions that
are a general perturbation about this form. This is done under the assumption
that the statistical properties of the data can be modelled by a multivariate
Gaussian distribution. We use this to show how one can optimise an experiment
to find evidence for a fixed function over perturbations about this function.
We apply this formalism to an illustrative problem of measuring perturbations
in the dark energy equation of state about a cosmological constant.
| arxiv topic:astro-ph.CO |
arxiv_dataset-64311507.05439 | Landau quantization and mass-radius relation of magnetized White Dwarfs
in general relativity
astro-ph.SR gr-qc nucl-th
Recently, several white dwarfs have been proposed with masses significantly
above the Chandrasekhar limit, known as Super-Chandrasekhar White Dwarfs, to
account for the overluminous Type Ia supernovae. In the present work, Equation
of State of a completely degenerate relativistic electron gas in magnetic field
based on Landau quantization of charged particles in a magnetic field is
developed. The mass-radius relations for magnetized White Dwarfs are obtained
by solving the Tolman-Oppenheimer-Volkoff equations. The effects of the
magnetic energy density and pressure contributed by a density-dependent
magnetic field are treated properly to find the stability configurations of
realistic magnetic White Dwarf stars.
| arxiv topic:astro-ph.SR gr-qc nucl-th |
arxiv_dataset-64321507.05539 | Putting Logic-Based Distributed Systems on Stable Grounds
cs.LO
In the Declarative Networking paradigm, Datalog-like languages are used to
express distributed computations. Whereas recently formal operational semantics
for these languages have been developed, a corresponding declarative semantics
has been lacking so far. The challenge is to capture precisely the amount of
nondeterminism that is inherent to distributed computations due to concurrency,
networking delays, and asynchronous communication. This paper shows how a
declarative, model-based semantics can be obtained by simply using the
well-known stable model semantics for Datalog with negation. We show that the
model-based semantics matches previously proposed formal operational semantics.
| arxiv topic:cs.LO |
arxiv_dataset-64331507.05639 | Fate of classical solitons in one-dimensional quantum systems
cond-mat.str-el
We study one-dimensional quantum systems near the classical limit described
by the Korteweg-de Vries (KdV) equation. The excitations near this limit are
the well-known solitons and phonons. The classical description breaks down at
long wavelengths, where quantum effects become dominant. Focusing on the
spectra of the elementary excitations, we describe analytically the entire
classical-to-quantum crossover. We show that the ultimate quantum fate of the
classical KdV excitations is to become fermionic particles and holes. We
discuss in detail two exactly solvable models exhibiting such crossover, the
Lieb-Liniger model of bosons with weak contact repulsion and the quantum Toda
model. We argue that the results obtained for these models are universally
applicable to all quantum one-dimensional systems with a well-defined classical
limit described by the KdV equation.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-64341507.05739 | Structural Analysis of Criminal Network and Predicting Hidden Links
using Machine Learning
cs.SI physics.soc-ph
Analysis of criminal networks is inherently difficult because of the nature
of the topic. Criminal networks are covert and most of the information is not
publicly available. This leads to small datasets available for analysis. The
available criminal network datasets consists of entities, i.e. individual or
organizations, which are linked to each other. The links between entities
indicates that there is a connection between these entities such as involvement
in the same criminal event, having commercial ties, and/or memberships in the
same criminal organization. Because of incognito criminal activities, there
could be many hidden links from entities to entities, which makes the publicly
available criminal networks incomplete. Revealing hidden links introduces new
information, e.g. affiliation of a suspected individual with a criminal
organization, which may not be known with public information. What will we be
able to find if we can run analysis on a larger dataset and use link prediction
to reveal the implicit connections? We plan to answer this question by using a
dataset that is an order of magnitude more than what is used in most criminal
networks analysis. And by using machine learning techniques, we will convert a
link prediction problem to a binary classification problem. We plan to reveal
hidden links and potentially hidden key attributes of the criminal network.
With a more complete picture of the network, we can potentially use this data
to thwart criminal organizations and/or take a Pareto approach in targeting key
nodes. We conclude our analysis with an effective destruction strategy to
weaken criminal networks and prove the effectiveness of revealing hidden links
when attacking to criminal networks.
| arxiv topic:cs.SI physics.soc-ph |
arxiv_dataset-64351507.05839 | Bose-Einstein condensates in neutron stars
nucl-th astro-ph.HE cond-mat.quant-gas hep-ph
In the two decades since the appearance of the book "Bose-Einstein
Condensation" in 1995, there have been a number of developments in our
understanding of dense matter. After a brief overview of neutron star structure
and the Bose-Einstein condensed phases that have been proposed, we describe
selected topics, including neutron and proton pairing gaps, the physics of the
inner crust of neutron stars, where a neutron fluid penetrates a lattice of
nuclei, meson condensates, and pairing in dense quark matter. Especial emphasis
is placed on basic physical effects and on connections to the physics of cold
atomic gases.
| arxiv topic:nucl-th astro-ph.HE cond-mat.quant-gas hep-ph |
arxiv_dataset-64361507.05939 | Reversibility and further properties of FCFS infinite bipartite matching
math.PR
The model of FCFS infinite bipartite matching was introduced in
caldentey-kaplan-weiss 2009. In this model there is a sequence of items that
are chosen i.i.d. from $\mathcal{C}=\{c_1,\ldots,c_I\}$ and an independent
sequence of items that are chosen i.i.d. from $\mathcal{S}=\{s_1,\ldots,s_J\}$,
and a bipartite compatibility graph $G$ between $\mathcal{C}$ and
$\mathcal{S}$. Items of the two sequences are matched according to the
compatibility graph, and the matching is FCFS, each item in the one sequence is
matched to the earliest compatible unmatched item in the other sequence. In
adan-weiss 2011 a Markov chain associated with the matching was analyzed, a
condition for stability was verified, a product form stationary distribution
was derived and the rates $r_{c_i,s_j}$ of matches between compatible types
$c_i$ and $s_j$ were calculated.
In the current paper, we present several new results that unveil the
fundamental structure of the model. First, we provide a pathwise Loynes' type
construction which enables to prove the existence of a unique matching for the
model defined over all the integers. Second, we prove that the model is
dynamically reversible: we define an exchange transformation in which we
interchange the positions of each matched pair, and show that the items in the
resulting permuted sequences are again independent and i.i.d., and the matching
between them is FCFS in reversed time. Third, we obtain product form stationary
distributions of several new Markov chains associated with the model. As a by
product, we compute useful performance measures, for instance the link lengths
between matched items.
| arxiv topic:math.PR |
arxiv_dataset-64371507.06039 | Multi-band Eilenberger theory of superconductivity: Systematic
low-energy projection
cond-mat.supr-con
We propose the general multi-band quasiclassical Eilenberger theory of
superconductivity to describe quasiparticle excitations in inhomogeneous
systems. With the use of low-energy projection matrix, the $M$-band
quasiclassical Eilenberger equations are systematically obtained from $N$-band
Gor'kov equations. Here $M$ is the internal degrees of freedom in the bands
crossing the Fermi energy and $N$ is the degree of freedom in a model. Our
framework naturally includes inter-band off-diagonal elements of Green's
functions, which have usually been neglected in previous multi-band
quasiclassical frameworks. The resultant multi-band Eilenberger and Andreev
equations are similar to the single-band ones, except for multi-band effects.
The multi-band effects can exhibit the non-locality and the anisotropy in the
mapped systems. Our framework can be applied to an arbitrary Hamiltonian (e.g.
a tight-binding Hamiltonian derived by the first-principle calculation). As
examples, we use our framework in various kinds of systems, such as
noncentrosymmetric superconductor CePt$_{3}$Si, three-orbital model for
Sr$_{2}$RuO$_{4}$, heavy fermion CeCoIn$_{5}$/YbCoIn$_{5}$ superlattice, a
topological superconductor with the strong spin-orbit coupling
Cu$_{x}$Bi$_{2}$Se$_{3}$, and a surface system on a topological insulator.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-64381507.06139 | Quantum Error Correction for State Transfer in Noisy Spin Chains
quant-ph
Can robustness against experimental imperfections and noise be embedded into
a quantum simulation? In this paper, we report on a special case in which this
is possible. A spin chain can be engineered such that, in the absence of
imperfections and noise, an unknown quantum state is transported from one end
of the chain to the other, due only to the intrinsic dynamics of the system. We
show that an encoding into a standard error correcting code (a
Calderbank-Shor-Steane code) can be embedded into this simulation task such
that a modified error correction procedure on read-out can recover from
sufficiently low rates of noise during transport.
| arxiv topic:quant-ph |
arxiv_dataset-64391507.06239 | Fast Desynchronization For Decentralized Multichannel Medium Access
Control
cs.SY cs.IT cs.MA math.IT math.OC
Distributed desynchronization algorithms are key to wireless sensor networks
as they allow for medium access control in a decentralized manner. In this
paper, we view desynchronization primitives as iterative methods that solve
optimization problems. In particular, by formalizing a well established
desynchronization algorithm as a gradient descent method, we establish novel
upper bounds on the number of iterations required to reach convergence.
Moreover, by using Nesterov's accelerated gradient method, we propose a novel
desynchronization primitive that provides for faster convergence to the steady
state. Importantly, we propose a novel algorithm that leads to decentralized
time-synchronous multichannel TDMA coordination by formulating this task as an
optimization problem. Our simulations and experiments on a densely-connected
IEEE 802.15.4-based wireless sensor network demonstrate that our scheme
provides for faster convergence to the steady state, robustness to hidden
nodes, higher network throughput and comparable power dissipation with respect
to the recently standardized IEEE 802.15.4e-2012 time-synchronized channel
hopping (TSCH) scheme.
| arxiv topic:cs.SY cs.IT cs.MA math.IT math.OC |
arxiv_dataset-64401507.06339 | Separation of Timescales in a Quantum Newton's Cradle
cond-mat.quant-gas
For strongly repulsive bosons in one dimension, we provide detailed modeling
of the Bragg pulse used in quantum Newton's cradle-like settings or in Bragg
spectroscopy experiments. By employing the Fermi-Bose mapping for a finite
harmonically trapped gas and the Quench Action approach for a thermodynamic
system on a ring, we reconstruct the exact post-pulse many-body time evolution
of Lieb-Liniger gases in the Tonks-Girardeau limit, together with their
changing local density profile and momentum distribution. Our results display a
clear separation of timescales between rapid and trap-insensitive relaxation
immediately after the pulse, followed by slow in-trap periodic behaviour.
| arxiv topic:cond-mat.quant-gas |
arxiv_dataset-64411507.06439 | Exact solutions for Weyl fermions with gravity
gr-qc hep-th math-ph math.MP
We consider the single-handed spinor field in interaction with its own
gravitational field described by the set of field equations given by Weyl field
equations written in terms of derivatives that are covariant with respect to
the gravitational connection plus Einstein field equations soured with the
energy tensor of the spinor: for the Weyl spinor and the ensuing spacetime of
Weyl-Lewis-Papapetrou structure, we will find all exact solutions. The obtained
solution for the metric tensor is that of a PP-wave spacetime while the spinor
field is a flag-dipole.
| arxiv topic:gr-qc hep-th math-ph math.MP |
arxiv_dataset-64421507.06539 | Multi-particle content of Majorana zero-modes in the interacting p-wave
wire
cond-mat.mes-hall
In the topological phase of p-wave superconductors, zero-energy Majorana
quasi-particle excitations can be well-defined in the presence of local
density-density interactions. Here we examine this phenomenon from the
perspective of matrix representations of the commutator $\mathcal{H}
=[H,\bullet]$ ,with the aim of characterising the multi-particle content of the
many-body Majorana mode. To do this we show that, for quadratic fermionic
systems, $\mathcal{H}$ can always be decomposed into sub-blocks that act as
multi-particle generalisations of the BdG/Majorana forms that encode
single-particle excitations. In this picture, density-density like interactions
will break this exact excitation-number symmetry, coupling different sub-blocks
and lifting degeneracies so that the eigen-operators of the commutator
$\mathcal{H}$ take the form of individual eigenstate transitions $|n\rangle
\langle m|$. However, the Majorana mode is special in that zero-energy
transitions are not destroyed by local interactions and it becomes possible to
define many-body Majoranas as the odd-parity zero-energy solutions of
$\mathcal{H}$ that minimise their excitation number. This idea forms the basis
for an algorithm which is used to characterise the multi-particle excitation
content of the Majorana zero modes of the one-dimensional p-wave lattice model.
We find that the multi-particle content of the Majorana zero-mode operators is
significant even at modest interaction strengths. This has important
consequences for the stability of Majorana based qubits when they are coupled
to a heat bath. We will also discuss how these findings differ from previous
work regarding the structure of the many-body-Majorana operators and point out
that this should affect how certain experimental features are interpreted.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-64431507.06639 | SKA Engineering Change Proposal: Gridded Visibilities to Enable
Precision Cosmology with Radio Weak Lensing
astro-ph.IM astro-ph.CO
This document was submitted as supporting material to an Engineering Change
Proposal (ECP) for the Square Kilometre Array (SKA). This ECP requests gridded
visibilities as an extra imaging data product from the SKA, in order to enable
bespoke analysis techniques to measure source morphologies to the accuracy
necessary for precision cosmology with radio weak lensing. We also discuss the
properties of an SKA weak lensing data set and potential overlaps with other
cosmology science goals.
| arxiv topic:astro-ph.IM astro-ph.CO |
arxiv_dataset-64441507.06739 | Selective inference with a randomized response
math.ST stat.TH
Inspired by sample splitting and the reusable holdout introduced in the field
of differential privacy, we consider selective inference with a randomized
response. We discuss two major advantages of using a randomized response for
model selection. First, the selectively valid tests are more powerful after
randomized selection. Second, it allows consistent estimation and weak
convergence of selective inference procedures. Under independent sampling, we
prove a selective (or privatized) central limit theorem that transfers
procedures valid under asymptotic normality without selection to their
corresponding selective counterparts. This allows selective inference in
nonparametric settings. Finally, we propose a framework of inference after
combining multiple randomized selection procedures. We focus on the classical
asymptotic setting, leaving the interesting high-dimensional asymptotic
questions for future work.
| arxiv topic:math.ST stat.TH |
arxiv_dataset-64451507.06839 | Intrinsic Instrumental Polarization and High-Precision Pulsar Timing
astro-ph.IM
Radio telescopes are used to accurately measure the time of arrival (ToA) of
radio pulses in pulsar timing experiments that target mostly millisecond
pulsars (MSPs) due to their high rotational stability. This allows for detailed
study of MSPs and forms the basis of experiments to detect gravitational waves.
Apart from intrinsic and propagation effects, such as pulse-to-pulse jitter and
dispersion variations in the interstellar medium, timing precision is limited
in part by the following: polarization purity of the telescope's orthogonally
polarized receptors, the signal-to-noise ratio (S/N) of the pulsar profile, and
the polarization fidelity of the system. Using simulations, we present how
fundamental limitations in recovering the true polarization reduce the
precision of ToA measurements. Any real system will respond differently to each
source observed depending on the unique pulsar polarization profile. Using the
profiles of known MSPs we quantify the limits of observing system
specifications that yield satisfactory ToA measurements, and we place a
practical design limit beyond which improvement of the system results in
diminishing returns. Our aim is to justify limits for the front-end
polarization characteristics of next generation radio telescopes, leading to
the Square Kilometre Array (SKA).
| arxiv topic:astro-ph.IM |
arxiv_dataset-64461507.06939 | Center problem, Abel equation and the Faa di Bruno Hopf algebra for
output feedback
math.RA math.CO
A combinatorial interpretation is given of Devlin's word problem underlying
the classical center-focus problem of Poincare for non-autonomous differential
equations. It turns out that the canonical polynomials of Devlin are from the
point of view of connected graded Hopf algebras intimately related to the
graded components of a Hopf algebra antipode applied to the formal power series
of Ferfera. The link is made by passing through control theory since the Abel
equation, which describes a center, is equivalent to an output feedback
equation, and the Hopf algebra of output feedback is derived from the
composition of iterated integrals rather than just the products of iterated
integrals, which yields the shuffle algebra. This means that the primary
algebraic structure at play in Devlin's approach is actually not the shuffle
algebra, but a Faa di Bruno type Hopf algebra, which is defined in terms of the
shuffle product but is a distinct algebraic structure.
| arxiv topic:math.RA math.CO |
arxiv_dataset-64471507.07039 | High Performance Computing of Gene Regulatory Networks using a
Message-Passing Model
q-bio.QM q-bio.MN
Gene regulatory network reconstruction is a fundamental problem in
computational biology. We recently developed an algorithm, called PANDA
(Passing Attributes Between Networks for Data Assimilation), that integrates
multiple sources of 'omics data and estimates regulatory network models. This
approach was initially implemented in the C++ programming language and has
since been applied to a number of biological systems. In our current research
we are beginning to expand the algorithm to incorporate larger and most diverse
data-sets, to reconstruct networks that contain increasing numbers of elements,
and to build not only single network models, but sets of networks. In order to
accomplish these "Big Data" applications, it has become critical that we
increase the computational efficiency of the PANDA implementation. In this
paper we show how to recast PANDA's similarity equations as matrix operations.
This allows us to implement a highly readable version of the algorithm using
the MATLAB/Octave programming language. We find that the resulting M-code much
shorter (103 compared to 1128 lines) and more easily modifiable for potential
future applications. The new implementation also runs significantly faster,
with increasing efficiency as the network models increase in size. Tests
comparing the C-code and M-code versions of PANDA demonstrate that this
speed-up is on the order of 20-80 times faster for networks of similar
dimensions to those we find in current biological applications.
| arxiv topic:q-bio.QM q-bio.MN |
arxiv_dataset-64481507.07139 | Nonparametric volatility estimation in scalar diffusions: Optimality
across observation frequencies
stat.AP math.PR
The nonparametric volatility estimation problem of a scalar diffusion process
observed at equidistant time points is addressed. Using the spectral
representation of the volatility in terms of the invariant density and an
eigenpair of the infinitesimal generator the first known estimator that attains
the minimax optimal convergence rates for both high and low-frequency
observations is constructed. The proofs are based on a posteriori error bounds
for generalized eigenvalue problems as well as the path properties of scalar
diffusions and stochastic analysis. The finite sample performance is
illustrated by a numerical example.
| arxiv topic:stat.AP math.PR |
arxiv_dataset-64491507.07239 | Halo effective field theory constrains the solar Beryllium-7 + proton ->
Boron-8 + photon rate
nucl-th astro-ph.SR nucl-ex
We report an improved low-energy extrapolation of the cross section for the
process Beryllium-7+proton -> Boron-8+photon, which determines the Boron-8
neutrino flux from the Sun. Our extrapolant is derived from Halo Effective
Field Theory (EFT) at next-to-leading order. We apply Bayesian methods to
determine the EFT parameters and the low-energy S-factor, using measured cross
sections and scattering lengths as inputs. Asymptotic normalization
coefficients of Boron-8 are tightly constrained by existing radiative capture
data, and contributions to the cross section beyond external direct capture are
detected in the data at E < 0.5 MeV. Most importantly, the S-factor at zero
energy is constrained to be S(0)= 21.3 + - 0.7 eV b, which is an uncertainty
smaller by a factor of two than previously recommended. That recommendation was
based on the full range for S(0) obtained among a discrete set of models judged
to be reasonable. In contrast, Halo EFT subsumes all models into a controlled
low-energy approximant, where they are characterized by nine parameters at
next-to-leading order. These are fit to data, and marginalized over via Monte
Carlo integration to produce the improved prediction for S(E).
| arxiv topic:nucl-th astro-ph.SR nucl-ex |
arxiv_dataset-64501507.07339 | Balancer effects in opinion dynamics
physics.soc-ph math.DS
We introduce a novel type of contrarian agent, the balancer, to Galam model
of opinion dynamics, in order to account for the existence of social skepticism
over one-sidedness. We find that the inclusion of balancers, along with
majoritarian floaters and single-sided inflexibles, brings about the emergence
of a critical point on parametric plane of the dynamical system. Around the
critical point, three distinct phases of opinion dynamics separated by
discontinuous changes are found.
| arxiv topic:physics.soc-ph math.DS |
arxiv_dataset-64511507.07439 | Centers of Leavitt path algebras and their completions
math.RA
In [8, 9] M. G. Corrales Garcia, D. M. Barquero, C. Martin Gonzalez, M. Siles
Molina, J. F Solanilla Hernandez described the center of a Leavitt path algebra
and characterized it in terms of the underlying graph. We offer a different
characterization of the center. In particular, we prove that the Boolean
algebra of central idempotents \ of a Leavitt path algebra of a finite graph is
isomorphic to the Boolean algebra of finitary annihilator hereditary subsets of
the graph.
| arxiv topic:math.RA |
arxiv_dataset-64521507.07539 | Transport through graphene-like flakes with intrinsic spin orbit
interactions
cond-mat.mes-hall
It has been shown recently [J. L. Lado et al., Phys. Rev. Lett. 113, 027203
(2014)] that edge magnetic moments in graphene-like nanoribbons are strongly
influenced by the intrinsic spin-orbit interaction. Due to this interaction an
anisotropy comes about which makes the in-plane arrangement of magnetic moments
energetically more favorable than that corresponding to the out-of-plane
configuration. In this paper we raise both the edge magnetism problem as well
as differential conductance and shot noise Fano factor issues, in the context
of finite-size flakes within the Coulomb blockade (CB) transport regime. Our
findings elucidate the following problems: (i) modification of the CB diamonds
by the appearance of the in-plane magnetic moments, (ii) modification of the CB
diamonds by intrinsic spin-orbit interaction.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-64531507.07639 | Family Gauge Boson Mass Estimated from $K^+ \rightarrow \pi^+ \nu
\bar{\nu}$
hep-ph
It is emphasized that a rare decay $K^+ \rightarrow \pi^+ \nu \bar{\nu}$
becomes promising in a future search for a new particle, because the
theoretical treatment is well established and the value of the branching ratio
$Br(K^+ \rightarrow \pi^+ \nu \bar{\nu})$ is sensitive to a search for a new
particle with a TeV scale mass. As an example, according to a U(3) family gauge
boson model which predicts the lowest family gauge boson with a few TeV mass
$M_{11}$, the branching ratio $Br(K^+ \rightarrow \pi^+ \nu \bar{\nu})$ is
discussed. If we can obtain, in future, a slightly lower value $Br^{obs} \sim
0.9 \times 10^{-10}$ compared with the present observed value $Br^{obs}=(1.7\pm
1.1)\times 10^{-10}$, we can conclude $M_{11} \sim$ a few TeV.
| arxiv topic:hep-ph |
arxiv_dataset-64541507.07739 | Forensic Analysis of WhatsApp Messenger on Android Smartphones
cs.CR
We present the forensic analysis of the artifacts left on Android devices by
\textit{WhatsApp Messenger}, the client of the WhatsApp instant messaging
system. We provide a complete description of all the artifacts generated by
WhatsApp Messenger, we discuss the decoding and the interpretation of each one
of them, and we show how they can be correlated together to infer various types
of information that cannot be obtained by considering each one of them in
isolation.
By using the results discussed in this paper, an analyst will be able to
reconstruct the list of contacts and the chronology of the messages that have
been exchanged by users. Furthermore, thanks to the correlation of multiple
artifacts, (s)he will be able to infer information like when a specific contact
has been added, to recover deleted contacts and their time of deletion, to
determine which messages have been deleted, when these messages have been
exchanged, and the users that exchanged them.
| arxiv topic:cs.CR |
arxiv_dataset-64551507.07839 | Simple top-down preparation of magnetic
Bi$_{0.9}$Gd$_{0.1}$Fe$_{1-x}$Ti$_x$O$_3$ nanoparticles by ultrasonication of
multiferroic bulk material
cond-mat.mes-hall
We present a simple technique to synthesize ultrafine nanoparticles directly
from bulk multiferroic perovskite powder. The starting materials, which were
ceramic pellets of the nominal compositions of
Bi$_{0.9}$Gd$_{0.1}$Fe$_{1-x}$Ti$_x$O$_3$ (x = 0.00-0.20), were prepared
initially by a solid state reaction technique, then ground into
micrometer-sized powders and mixed with isopropanol or water in an ultrasonic
bath. The particle size was studied as a function of sonication time with
transmission electron microscopic imaging and electron diffraction that
confirmed the formation of a large fraction of single-crystalline nanoparticles
with a mean size of 11-13 nm. A significant improvement in the magnetic
behavior of Bi$_{0.9}$Gd$_{0.1}$Fe$_{1-x}$Ti$_x$O$_3$ nanoparticles compared to
their bulk counterparts was observed at room temperature. This sonication
technique may be considered as a simple and promising route to prepare
ultrafine nanoparticles for functional applications.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-64561507.07939 | SHARDS: A global view of the star formation activity at z~0.84 and
z~1.23
astro-ph.GA
In this paper, we present a comprehensive analysis of star-forming galaxies
(SFGs) at intermediate redshifts (z~1). We combine the ultra-deep optical
spectro-photometric data from the Survey for High-z Absorption Red and Dead
Sources (SHARDS) with deep UV-to-FIR observations in the GOODS-N field.
Exploiting two of the 25 SHARDS medium-band filters, F687W17 and F823W17, we
select [OII] emission line galaxies at z~0.84 and z~1.23 and characterize their
physical properties. Their rest-frame equivalent widths
(EW$_{\mathrm{rf}}$([OII])), line fluxes, luminosities, star formation rates
(SFRs) and dust attenuation properties are investigated. The evolution of the
EW$_{\mathrm{rf}}$([OII]) closely follows the SFR density evolution of the
universe, with a trend of EW$_{\mathrm{rf}}$([OII])$\propto$(1+z)$^3$ up to
redshift z~1, followed by a possible flattening. The SF properties of the
galaxies selected on the basis of their [OII] emission are compared with
complementary samples of SFGs selected by their MIR and FIR emission, and also
with a general mass-selected sample of galaxies at the same redshifts. We
demonstrate observationally that the UVJ diagram (or, similarly, a cut in the
specific SFR) is only partially able to distinguish the quiescent galaxies from
the SFGs. The SFR-M$_*$ relation is investigated for the different samples,
yelding a logarithmic slope ~1, in good agreement with previous results. The
dust attenuations derived from different SFR indicators (UV(1600), UV(2800),
[OII], IR) are compared and show clear trends with respect to both the stellar
mass and total SFR, with more massive and highly star-forming galaxies being
affected by stronger dust attenuation.
| arxiv topic:astro-ph.GA |
arxiv_dataset-64571507.08039 | A natural extension of the conformal Lorentz group in a field theory
context
math-ph hep-th math.MP
In this paper a finite dimensional unital associative algebra is presented,
and its group of algebra automorphisms is detailed. The studied algebra can
physically be understood as the creation operator algebra in a formal quantum
field theory at fixed momentum for a spin 1/2 particle along with its
antiparticle. It is shown that the essential part of the corresponding
automorphism group can naturally be related to the conformal Lorentz group. In
addition, the non-semisimple part of the automorphism group can be understood
as "dressing" of the pure one-particle states. The studied mathematical
structure may help in constructing quantum field theories in a non-perturbative
manner. In addition, it provides a simple example of circumventing
Coleman-Mandula theorem using non-semisimple groups, without SUSY.
| arxiv topic:math-ph hep-th math.MP |
arxiv_dataset-64581507.08139 | Flow Rounding
cs.DS
We consider flow rounding: finding an integral flow from a fractional flow.
Costed flow rounding asks that we find an integral flow with no worse cost.
Randomized flow rounding requires we randomly find an integral flow such that
the expected flow along each edge matches the fractional flow. Both problems
are reduced to cycle canceling, for which we develop an $O(m \log(n^2/m))$
algorithm.
| arxiv topic:cs.DS |
arxiv_dataset-64591507.08239 | Trajectory statistics and turbulence evolution
physics.flu-dyn
The aim of this paper is to understand the tendency to organization of the
turbulence in two-dimensional ideal fluids. We show that nonlinear processes as
inverse cascade of the energy and vorticity concentration are essentially
determined by trajectory trapping or eddying. The statistics of the
trajectories of the vorticity elements is studied using a semianalytic method.
The separation of the positive and negative vorticity is due to the attraction
produced by a large scale vortex on the small scale vortices of the same sign.
More precisely, a large scale velocity is shown to determine average transverse
drifts, which have opposite orientations for positive and negative vorticity.
They appear in the presence of trapping and lead to energy flow to large scales
due to the increase of the circulation of the large vortex. Recent results on
drift turbulence evolution in magnetically confined plasmas are discussed in
order to underline the idea that there is a link between the inverse cascade
and trajectory trapping. The physical mechanisms are different in fluids and
plasmas due to the different types of nonlinearities of the two systems, but
trajectory trapping has the main role in both cases.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-64601507.08339 | Inspection games in a mean field setting
math.OC math.PR
In this paper, we present a new development of inspection games in a mean
field setting. In our dynamic version of an inspection game, there is one
inspector and a large number N interacting inspectees with a finite state
space. By applying the mean field game methodology, we present a solution as an
epsilon-equilibrium to this type of inspection games, where epsilon goes to 0
as N tends to infinity. In order to facilitate numerical analysis of this new
type inspection game, we conduct an approximation analysis, that is we
approximate the optimal Lipschitz continuous switching strategies by smooth
switching strategies. We show that any approximating smooth switching strategy
is also an epsilon-equilibrium solution to the inspection game with a large and
finite number N of inspectees with epsilon being of order 1/N.
| arxiv topic:math.OC math.PR |
arxiv_dataset-64611507.08439 | Metadata Embeddings for User and Item Cold-start Recommendations
cs.IR
I present a hybrid matrix factorisation model representing users and items as
linear combinations of their content features' latent factors. The model
outperforms both collaborative and content-based models in cold-start or sparse
interaction data scenarios (using both user and item metadata), and performs at
least as well as a pure collaborative matrix factorisation model where
interaction data is abundant. Additionally, feature embeddings produced by the
model encode semantic information in a way reminiscent of word embedding
approaches, making them useful for a range of related tasks such as tag
recommendations.
| arxiv topic:cs.IR |
arxiv_dataset-64621507.08539 | Multilayer Network of Language: a Unified Framework for Structural
Analysis of Linguistic Subsystems
cs.CL
Recently, the focus of complex networks research has shifted from the
analysis of isolated properties of a system toward a more realistic modeling of
multiple phenomena - multilayer networks. Motivated by the prosperity of
multilayer approach in social, transport or trade systems, we propose the
introduction of multilayer networks for language. The multilayer network of
language is a unified framework for modeling linguistic subsystems and their
structural properties enabling the exploration of their mutual interactions.
Various aspects of natural language systems can be represented as complex
networks, whose vertices depict linguistic units, while links model their
relations. The multilayer network of language is defined by three aspects: the
network construction principle, the linguistic subsystem and the language of
interest. More precisely, we construct a word-level (syntax, co-occurrence and
its shuffled counterpart) and a subword level (syllables and graphemes) network
layers, from five variations of original text (in the modeled language). The
obtained results suggest that there are substantial differences between the
networks structures of different language subsystems, which are hidden during
the exploration of an isolated layer. The word-level layers share structural
properties regardless of the language (e.g. Croatian or English), while the
syllabic subword level expresses more language dependent structural properties.
The preserved weighted overlap quantifies the similarity of word-level layers
in weighted and directed networks. Moreover, the analysis of motifs reveals a
close topological structure of the syntactic and syllabic layers for both
languages. The findings corroborate that the multilayer network framework is a
powerful, consistent and systematic approach to model several linguistic
subsystems simultaneously and hence to provide a more unified view on language.
| arxiv topic:cs.CL |
arxiv_dataset-64631507.08639 | Nature of the Quantum Metal in a Two-Dimensional Crystalline
Superconductor
cond-mat.supr-con
Two-dimensional (2D) materials are not expected to be metals at low
temperature due to electron localization. Consistent with this, pioneering
studies on thin films reported only superconducting and insulating ground
states, with a direct transition between the two as a function of disorder or
magnetic field. However, more recent works have revealed the presence of an
intermediate metallic state occupying a substantial region of the phase diagram
whose nature is intensely debated. Here, we observe such a state in the
disorder-free limit of a crystalline 2D superconductor, produced by mechanical
co-lamination of NbSe$_2$ in inert atmosphere. Under a small perpendicular
magnetic field, we induce a transition from superconductor to the intermediate
metallic state. We find a new power law scaling with field in this phase, which
is consistent with the Bose metal model where metallic behavior arises from
strong phase fluctuations caused by the magnetic field.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-64641507.08739 | Magnetospherically driven optical and radio aurorae at the end of the
stellar main sequence
astro-ph.SR
Aurorae are detected from all the magnetized planets in our Solar System,
including Earth. They are powered by magnetospheric current systems that lead
to the precipitation of energetic electrons into the high-latitude regions of
the upper atmosphere. In the case of the gas-giant planets, these aurorae
include highly polarized radio emission at kilohertz and megahertz frequencies
produced by the precipitating electrons, as well as continuum and line emission
in the infrared, optical, ultraviolet and X-ray parts of the spectrum,
associated with the collisional excitation and heating of the
hydrogen-dominated atmosphere. Here we report simultaneous radio and optical
spectroscopic observations of an object at the end of the stellar main
sequence, located right at the boundary between stars and brown dwarfs, from
which we have detected radio and optical auroral emissions both powered by
magnetospheric currents. Whereas the magnetic activity of stars like our Sun is
powered by processes that occur in their lower atmospheres, these aurorae are
powered by processes originating much further out in the magnetosphere of the
dwarf star that couple energy into the lower atmosphere. The dissipated power
is at least four orders of magnitude larger than what is produced in the Jovian
magnetosphere, revealing aurorae to be a potentially ubiquitous signature of
large-scale magnetospheres that can scale to luminosities far greater than
those observed in our Solar System. These magnetospheric current systems may
also play a part in powering some of the weather phenomena reported on brown
dwarfs.
| arxiv topic:astro-ph.SR |
arxiv_dataset-64651507.08839 | Exact calculations of a quasi-bound state in the $\bar{K} \bar{K} N$
system
nucl-th
Dynamically exact calculations of a quasi-bound state in the
$\bar{K}\bar{K}N$ three-body system are performed using Faddeev-type AGS
equations. As input two phenomenological and one chirally motivated $\bar{K}N$
potentials are used, which describe the experimental information on the
$\bar{K}N$ system equally well and produce either a one- or two-pole structure
of the $\Lambda(1405)$ resonance. For the $\bar{K}\bar{K}$ interaction
separable potentials are employed that are fitted to phase shifts obtained from
two theoretical models. The first one is a phenomenological $\bar{K}\bar{K}$
potential based on meson exchange, which is derived by SU(3) symmetry arguments
from the J\"ulich $\pi \pi - \bar{K} K$ coupled-channels model. The other
interaction is a variant of the first one, which is adjusted to the $KK$ s-wave
scattering length recently determined in lattice QCD simulations. The position
and width of the $\bar{K}\bar{K}N$ quasi-bound state is evaluated in two ways:
(i) by a direct pole search in the complex energy plane and (ii) using an
"inverse determinant" method, where one needs to calculate the determinant of
the AGS system of equations only for real energies. A quasi-bound state is
found with binding energy $B_{\bar{K}\bar{K}N} = 12 - 26$ MeV and width
$\Gamma_{\bar{K}\bar{K}N} = 61 - 102$ MeV, which could correspond to the
experimentally observed $\Xi(1950)$ state.
| arxiv topic:nucl-th |
arxiv_dataset-64661507.08939 | An exotic symplectic $\mathbf{R}^6$
math.DG
An explicit example of an exotic symplectic $\mathbf{R}^6$ is given. Together
with an earlier known example on $\mathbf{R}^4$, this yields an explicit exotic
symplectic form on $\mathbf{R}^{2n}$ for all $n\geq2$.
| arxiv topic:math.DG |
arxiv_dataset-64671508.00044 | How Students Use Media: A Comparison across Faculties
cs.CY
The pervasiveness of online information services has led to substantial
changes in higher education including changes in faculty members teaching
methods and students study habits. This article presents the results of a
survey about media use for teaching and learning conducted at a large Canadian
university and highlights trends in the use of new and traditional media across
university Faculties. The results of this study support the assumption that
student media usage includes a mixture of traditional and new media.
| arxiv topic:cs.CY |
arxiv_dataset-64681508.00144 | Quantitative evaluation of the performance of discrete-time reservoir
computers in the forecasting, filtering, and reconstruction of stochastic
stationary signals
cs.ET cs.NE math.ST stat.TH
This paper extends the notion of information processing capacity for
non-independent input signals in the context of reservoir computing (RC). The
presence of input autocorrelation makes worthwhile the treatment of forecasting
and filtering problems for which we explicitly compute this generalized
capacity as a function of the reservoir parameter values using a streamlined
model. The reservoir model leading to these developments is used to show that,
whenever that approximation is valid, this computational paradigm satisfies the
so called separation and fading memory properties that are usually associated
with good information processing performances. We show that several standard
memory, forecasting, and filtering problems that appear in the parametric
stochastic time series context can be readily formulated and tackled via RC
which, as we show, significantly outperforms standard techniques in some
instances.
| arxiv topic:cs.ET cs.NE math.ST stat.TH |
arxiv_dataset-64691508.00244 | Asymptotic Shapes for Ergodic Families of Metrics on Nilpotent Groups
math.GR math.DS
Let Gamma be a finitely generated nilpotent group. We consider three closely
related problems: (i) the asymptotic cone for an equivariant ergodic family of
inner metrics on Gamma, generalizing Pansu's theorem; (ii) the limit shapes for
First Passage Percolation for general (not necessarily independent) ergodic
processes on edges of a Cayley graph of Gamma; (iii) a sub-additive ergodic
theorem over a general ergodic Gamma-action. The limiting objects are given in
terms of a Carnot-Caratheodory metric on the graded nilpotent group associated
to the Mal'cev completion of Gamma.
| arxiv topic:math.GR math.DS |
arxiv_dataset-64701508.00344 | Scattering of particles by deformed non-rotating black holes
gr-qc astro-ph.HE
We study the excitation of axial quasi-normal modes of deformed non-rotating
black holes by test-particles and we compare the associated gravitational wave
signal with that expected in general relativity from a Schwarzschild black
hole. Deviations from standard predictions are quantified by an effective
deformation parameter, which takes into account deviations from both the
Schwarzschild metric and the Einstein equations. We show that, at least in the
case of non-rotating black holes, it is possible to test the metric around the
compact object, in the sense that the measurement of the gravitational wave
spectrum can constrain possible deviations from the Schwarzschild solution.
| arxiv topic:gr-qc astro-ph.HE |
arxiv_dataset-64711508.00444 | Smoothing estimates for non-dispersive equations
math.AP math.FA
This paper describes an approach to global smoothing problems for
non-dispersive equations based on ideas of comparison principle and canonical
transformation established in authors' previous paper, where dispersive
equations were treated. For operators $a(D_x)$ of order $m$ satisfying the
dispersiveness condition $\nabla a(\xi)\neq0$ for $\xi\not=0$, the global
smoothing estimate $$ \|\langle x\rangle^{-s}|D_x|^{(m-1)/2}e^{ita(D_x)}
\varphi(x)\|_{L^2(\mathbb R_t\times\mathbb R^n_x)} \leq
C\|\varphi\|_{L^2(\mathbb R^n_x)} \quad {\rm(}s>1/2{\rm)} $$ is well-known,
while it is also known to fail for non-dispersive operators. For the case when
the dispersiveness breaks, we suggest the estimate in the form $$
\|{\langle{x}\rangle^{-s}|\nabla a(D_x)|^{1/2} e^{it
a(D_x)}\varphi(x)}\|_{L^2({\mathbb R_t\times\mathbb R^n_x})} \leq
C\|{\varphi}\|_{L^2({\mathbb R^n_x})}\quad{\rm(}s>1/2{\rm)} $$ which is
equivalent to the usual estimate in the dispersive case and is also invariant
under canonical transformations for the operator $a(D_x)$. We show that this
estimate and its variants do continue to hold for a variety of non-dispersive
operators $a(D_x)$, where $\nabla a(\xi)$ may become zero on some set.
Moreover, other types of such estimates, and the case of time-dependent
equations are also discussed.
| arxiv topic:math.AP math.FA |
arxiv_dataset-64721508.00544 | Canonical Realization of BMS Symmetry. Quadratic Casimir
hep-th
We study the canonical realization of BMS symmetry for a massive scalar field
introduced in reference \cite{LM}. We will construct an invariant scalar
product for the generalized momenta. As a consequence we will introduce a
quadratic Casimir with the supertranslations.
| arxiv topic:hep-th |
arxiv_dataset-64731508.00644 | Optical-Infrared Properties of Faint 1.3 mm Sources Detected with ALMA
astro-ph.GA
We report optical-infrared (IR) properties of faint 1.3 mm sources (S_1.3mm =
0.2-1.0 mJy) detected with the Atacama Large Millimeter/submillimeter Array
(ALMA) in the Subaru/XMM-Newton Deep Survey (SXDS) field. We searched for
optical/IR counterparts of 8 ALMA-detected sources (>=4.0 sigma, the sum of the
probability of spurious source contamination is ~1) in a K-band source catalog.
Four ALMA sources have K-band counterpart candidates within a 0.4" radius.
Comparison between ALMA-detected and undetected K-band sources in the same
observing fields shows that ALMA-detected sources tend to be brighter, more
massive, and more actively forming stars. While many of the ALMA-identified
submillimeter-bright galaxies (SMGs) in previous studies lie above the sequence
of star-forming galaxies in stellar mass--star-formation rate plane, our ALMA
sources are located in the sequence, suggesting that the ALMA-detected faint
sources are more like `normal' star-forming galaxies rather than `classical'
SMGs. We found a region where multiple ALMA sources and K-band sources reside
in a narrow photometric redshift range (z ~ 1.3-1.6) within a radius of 5" (42
kpc if we assume z = 1.45). This is possibly a pre-merging system and we may be
witnessing the early phase of formation of a massive elliptical galaxy.
| arxiv topic:astro-ph.GA |
arxiv_dataset-64741508.00744 | Low-energy singlet excitations in spin- 1/2 Heisenberg antiferromagnet
on square lattice
cond-mat.str-el
We present an approach based on a dimer expansion which describes low-energy
singlet excitations (singlons) in spin-$\frac12$ Heisenberg antiferromagnet on
simple square lattice. An operator ("effective Hamiltonian") is constructed
whose eigenvalues give the singlon spectrum. The "effective Hamiltonian" looks
like a Hamiltonian of a spin-$\frac12$ magnet in strong external magnetic field
and it has a gapped spectrum. It is found that singlet states lie above triplet
ones (magnons) in the whole Brillouin zone except in the vicinity of the point
$(\pi,0)$, where their energies are slightly smaller. Based on this finding, we
suggest that a magnon decay is possible near $(\pi,0)$ into another magnon and
a singlon which may contribute to the dip of the magnon spectrum near $(\pi,0)$
and reduce the magnon lifetime. It is pointed out that the singlon-magnon
continuum may contribute to the continuum of excitations observed recently near
$(\pi,0)$.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-64751508.00844 | Canonical formulation and conserved charges of double field theory
hep-th
We provide the canonical formulation of double field theory. It is shown that
this dynamics is subject to primary and secondary constraints. The Poisson
bracket algebra of secondary constraints is shown to close on-shell according
to the C-bracket. A systematic way of writing boundary integrals in doubled
geometry is given. By including appropriate boundary terms in the double field
theory Hamiltonian, expressions for conserved energy and momentum of an
asymptotically flat doubled space-time are obtained and applied to a number of
solutions.
| arxiv topic:hep-th |
arxiv_dataset-64761508.00944 | On the weak limit law of the maximal uniform k-spacing
math.PR
This paper gives a simple proof of a limit theorem for the lenght of the
largest interval straddling a fixed number of i.i.d. points uniformly
disributed on a unit interval. The key step in our argument is a classical
theorem of Watson (1954) on the maxima of m-dependent stationary stochastic
sequences.
| arxiv topic:math.PR |
arxiv_dataset-64771508.01044 | Vertical-Cavity In-plane Heterostructures: Physics and Applications
physics.optics
We show that the in-plane heterostructures realized in vertical cavities with
high contrast grating(HCG) reflector enables exotic configurations of
heterostructure and photonic wells. In photonic crystal heterostructures
forming a photonic well, the property of a confined mode is determined by the
well width and barrier height. We show that in vertical-cavity in-plane
heterostructures, anisotropic dispersion curvatures plays a key role as well,
leading to exotic effects such as a photonic well with conduction band like
well and a valence band like barrier. We investigate three examples to discuss
the rich potential of this heterostructure as a platform for various physics
studies and propose a system of two laterally coupled cavities which shows the
breaking of parity-time symmetry as an example.
| arxiv topic:physics.optics |
arxiv_dataset-64781508.01144 | Effective Single Photon Decay Mode of Positronium Decay via Electroweak
Interactions
physics.atom-ph hep-ph physics.chem-ph quant-ph
We consider the decay of positronium to a neutrino-antineutrino accompanied
by a single photon. Since the neutrino pair go undetected, this appears as a
single photon decay of positronium. These decay channel are mediated through
the exchange of the massive $W$ and $Z$ vector bosons of the electroweak
interaction. After summing over the various neutrino channels, the standard
model calculation yields the rate for such a single photon decay process of
$\Gamma_{Ps \rightarrow \gamma}$ = 1.72 $\times 10^{-19}$ s$^{-1}$.
| arxiv topic:physics.atom-ph hep-ph physics.chem-ph quant-ph |
arxiv_dataset-64791508.01244 | TabletGaze: Unconstrained Appearance-based Gaze Estimation in Mobile
Tablets
cs.CV
We study gaze estimation on tablets, our key design goal is uncalibrated gaze
estimation using the front-facing camera during natural use of tablets, where
the posture and method of holding the tablet is not constrained. We collected
the first large unconstrained gaze dataset of tablet users, labeled Rice
TabletGaze dataset. The dataset consists of 51 subjects, each with 4 different
postures and 35 gaze locations. Subjects vary in race, gender and in their need
for prescription glasses, all of which might impact gaze estimation accuracy.
Driven by our observations on the collected data, we present a TabletGaze
algorithm for automatic gaze estimation using multi-level HoG feature and
Random Forests regressor. The TabletGaze algorithm achieves a mean error of
3.17 cm. We perform extensive evaluation on the impact of various factors such
as dataset size, race, wearing glasses and user posture on the gaze estimation
accuracy and make important observations about the impact of these factors.
| arxiv topic:cs.CV |
arxiv_dataset-64801508.01344 | The performance of a combined solar photovoltaic (PV) and thermoelectric
generator (TEG) system
physics.ins-det
The performance of a combined solar photovoltaic (PV) and thermoelectric
generator (TEG) system is examined using an analytical model for four different
types of commercial PVs and a commercial bismuth telluride TEG. The TEG is
applied directly on the back of the PV, so that the two devices have the same
temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si),
copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells.
The degradation of PV performance with temperature is shown to dominate the
increase in power produced by the TEG, due to the low efficiency of the TEG.
For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and
has a lower efficiency than the PV alone, whereas for an a-Si cell the total
system performance may be slightly increased by the TEG.
| arxiv topic:physics.ins-det |
arxiv_dataset-64811508.01444 | Two Extensions of the Sury's Identity
math.CO math.NT
In this note we prove two extensions of the Sury's identity.
| arxiv topic:math.CO math.NT |
arxiv_dataset-64821508.01544 | Approximating Ground and Excited State Energies on a Quantum Computer
quant-ph
Approximating ground and a fixed number of excited state energies, or
equivalently low order Hamiltonian eigenvalues, is an important but
computationally hard problem. Typically, the cost of classical deterministic
algorithms grows exponentially with the number of degrees of freedom. Under
general conditions, and using a perturbation approach, we provide a quantum
algorithm that produces estimates of a constant number $j$ of different low
order eigenvalues. The algorithm relies on a set of trial eigenvectors, whose
construction depends on the particular Hamiltonian properties. We illustrate
our results by considering a special case of the time-independent Schr\"odinger
equation with $d$ degrees of freedom. Our algorithm computes estimates of a
constant number $j$ of different low order eigenvalues with error $O(\epsilon)$
and success probability at least $\frac34$, with cost polynomial in
$\frac{1}{\epsilon}$ and $d$. This extends our earlier results on algorithms
for estimating the ground state energy. The technique we present is
sufficiently general to apply to problems beyond the application studied in
this paper.
| arxiv topic:quant-ph |
arxiv_dataset-64831508.01644 | Verifiable Conditions for the Irreducibility and Aperiodicity of Markov
Chains by Analyzing Underlying Deterministic Models
math.PR
We consider Markov chains that obey the following general non-linear state
space model: $\Phi_{k+1} = F(\Phi_k, \alpha(\Phi_k, U_{k+1}))$ where the
function $F$ is $C^1$ while $\alpha$ is typically discontinuous and $\{U_k: k
\in \mathbb{Z}_{> 0} \}$ is an independent and identically distributed process.
We assume that for all $x$, the random variable $\alpha(x, U_1)$ admits a
density $p_x$ such that $(x, w) \mapsto p_x(w)$ is lower semi-continuous.
We generalize and extend previous results that connect properties of the
underlying deterministic control model to provide conditions for the chain to
be $\varphi$-irreducible and aperiodic. By building on those results, we show
that if a rank condition on the controllability matrix is satisfied for all
$x$, there is equivalence between the existence of a globally attracting state
for the control model and $\varphi$-irreducibility of the Markov chain.
Additionally, under the same rank condition on the controllability matrix, we
prove that there is equivalence between the existence of a steadily attracting
state and the $\varphi$-irreducibility and aperiodicity of the chain. The
notion of steadily attracting state is new.
Those results hold under considerably weaker assumptions on the model than
previous ones that would require $(x,u) \mapsto F(x,\alpha(x,u))$ to be
$C^\infty$ (while it can be discontinuous here). Additionally the establishment
of a necessary and sufficient condition for the $\varphi$-irreducibility and
aperiodicity without a structural assumption on the control set is novel---even
for Markov chains where $(x,u) \mapsto F(x,\alpha(x,u))$ is $C^\infty$.
We illustrate that the conditions are easy to verify on a non-trivial and
non-artificial example of Markov chain arising in the context of adaptive
stochastic search algorithms to optimize continuous functions in a black-box
scenario.
| arxiv topic:math.PR |
arxiv_dataset-64841508.01744 | Proximate transition temperatures amplify linear magnetoelectric
coupling in strain-disordered multiferroic BiMnO3
cond-mat.mtrl-sci
We report a giant linear magnetoelectric coupling in strained BiMnO3 thin
films in which the disorder associated with an islanded morphology gives rise
to extrinsic relaxor ferroelectricity that is not present in bulk
centrosymmetric ferromagnetic crystalline BiMnO3. Strain associated with the
disorder is treated as a local variable which couples to the two ferroic order
parameters, magnetization M and polarization P. A straightforward "gas under a
piston" thermodynamic treatment explains the observed correlated temperature
dependencies of the product of susceptibilities and the magnetoelectric
coefficient together with the enhancement of the coupling by the proximity of
the ferroic transition temperatures close to the relaxor freezing temperature.
Our interpretation is based on a trilinear coupling term in the free energy of
the form L(PXM) where L is a hidden antiferromagnetic order parameter,
previously postulated by theory for BiMnO3. This phenomenological invariant not
only preserves inversion and time reversal symmetry of the strain-induced
interactions but also explains the pronounced linear magnetoelectric coupling
without using the more conventional higher order biquadratic interaction
proportional to (PM)^2.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-64851508.01844 | The topology of Kuranishi atlases
math.SG
Kuranishi structures were introduced in the 1990s by Fukaya and Ono for the
purpose of assigning a virtual cycle to moduli spaces of pseudoholomorphic
curves that cannot be regularized by geometric methods. Starting from the same
core idea (patching local finite dimensional reductions) we develop a theory of
topological Kuranishi atlases and cobordisms that transparently resolves
algebraic and topological challenges in this virtual regularization approach.
It applies to any Kuranishi-type setting, e.g. atlases with isotropy, boundary
and corners, or lack of differentiable structure.
| arxiv topic:math.SG |
arxiv_dataset-64861508.01944 | Functorial CW-approximation
math.AT
The usual construction of a CW-approximation is functorial up to homotopy,
but it is not functorial. In this note, we construct a functorial
CW-approximation. Our construction takes inclusions of subspaces into
inclusions of subcomplexes, and commutes with intersections of subspaces of a
fixed space.
| arxiv topic:math.AT |
arxiv_dataset-64871508.02044 | Mode mixing in sub- and trans-critical flows over an obstacle: When
should Hawking's predictions be recovered?
gr-qc physics.flu-dyn
We reexamine the scattering coefficients of shallow water waves blocked by a
stationary counter current over an obstacle. By considering series of
background flows, we show that the most relevant parameter is $F_{\rm max}$,
the maximal value of the ratio of the flow velocity over the speed of low
frequency waves. For subcritical flows, i.e., $F_{\rm max} < 1$, there is no
analogue Killing horizon and the mode amplification is strongly suppressed.
Instead, when $F_{\rm max} \gtrsim 1.1$, the amplification is enhanced at low
frequency and the spectrum closely follows Hawking's prediction. We further
study subcritical flows close to that used in the Vancouver experiment. Our
numerical analysis suggests that their observation of the "thermal nature of
the mode conversion" is due to the relatively steep slope on the upstream side
and the narrowness of the obstacle.
| arxiv topic:gr-qc physics.flu-dyn |
arxiv_dataset-64881508.02144 | Renormalisation of q-regularised multiple zeta values
math.NT math-ph math.MP
We consider a particular one-parameter family of q-analogues of multiple zeta
values. The intrinsic q-regularisation permits an extension of these q-multiple
zeta values to negative integers. Renormalised multiple zeta values satisfying
the quasi-shuffle product are obtained using an Hopf algebraic Birkhoff
factorisation together with minimal subtraction.
| arxiv topic:math.NT math-ph math.MP |
arxiv_dataset-64891508.02244 | France new regions planning? Better order or more disorder ?
physics.soc-ph nlin.AO stat.AP
This paper grounds the critique of the 'reduction of regions in a country'
not only in its geographical and social context but also in its entropic space.
The various recent plans leading to the reduction of the number of regions in
metropolitan France are discussed, based on the mere distribution in the number
of cities in the plans and analyzed according to various distribution laws.
Each case, except the present distribution with 22 regions, on the mainland,
does not seem to fit presently used theoretical models. Beside, the number of
inhabitants is examined in each plan. The same conclusion holds. Therefore a
theoretical argument based on entropy considerations is proposed, thereby
pointing to whether more order or less disorder is the key question, -
discounting political considerations.
| arxiv topic:physics.soc-ph nlin.AO stat.AP |
arxiv_dataset-64901508.02344 | Local Algorithms for Block Models with Side Information
stat.ML cs.CC cs.DC math.PR
There has been a recent interest in understanding the power of local
algorithms for optimization and inference problems on sparse graphs. Gamarnik
and Sudan (2014) showed that local algorithms are weaker than global algorithms
for finding large independent sets in sparse random regular graphs. Montanari
(2015) showed that local algorithms are suboptimal for finding a community with
high connectivity in the sparse Erd\H{o}s-R\'enyi random graphs. For the
symmetric planted partition problem (also named community detection for the
block models) on sparse graphs, a simple observation is that local algorithms
cannot have non-trivial performance.
In this work we consider the effect of side information on local algorithms
for community detection under the binary symmetric stochastic block model. In
the block model with side information each of the $n$ vertices is labeled $+$
or $-$ independently and uniformly at random; each pair of vertices is
connected independently with probability $a/n$ if both of them have the same
label or $b/n$ otherwise. The goal is to estimate the underlying vertex
labeling given 1) the graph structure and 2) side information in the form of a
vertex labeling positively correlated with the true one. Assuming that the
ratio between in and out degree $a/b$ is $\Theta(1)$ and the average degree $
(a+b) / 2 = n^{o(1)}$, we characterize three different regimes under which a
local algorithm, namely, belief propagation run on the local neighborhoods,
maximizes the expected fraction of vertices labeled correctly. Thus, in
contrast to the case of symmetric block models without side information, we
show that local algorithms can achieve optimal performance for the block model
with side information.
| arxiv topic:stat.ML cs.CC cs.DC math.PR |
arxiv_dataset-64911508.02444 | Emergent Universality in Nonequilibrium Processes of Critical Systems
cond-mat.stat-mech cond-mat.mes-hall
We examine the Jarzynski equality for a quenching process across the critical
point of second-order phase transitions, where absolute irreversibility and the
effect of finite-sampling of the initial equilibrium distribution arise on an
equal footing. We consider the Ising model as a prototypical example for
spontaneous symmetry breaking and take into account the finite sampling issue
by introducing a tolerance parameter. For a given tolerance parameter, the
deviation from the Jarzynski equality depends onthe reduced coupling constant
and the system size. In this work, we show that the deviation from the
Jarzynski equality exhibits a universal scaling behavior inherited from the
critical scaling laws of second-order phase transitions.
| arxiv topic:cond-mat.stat-mech cond-mat.mes-hall |
arxiv_dataset-64921508.02544 | CGC/saturation approach: a new impact-parameter dependent model
hep-ph
{In this paper we propose a new impact-parameter dependent CGC/saturation
model. We introduce two new features in the model that make it consistent with
what we know theoretically about the deep inelastic scattering. They are: the
use of the exact form of the solution to the non-linear (BK) equation, whereas
in all previous attempts only the form of $r^2Q^2_s$ dependence, has been taken
into account; and the large impact parameter dependence, through the
$b$-dependence of the saturation momentum which reproduce the correct behaviour
of the amplitude at large impact parameters $b$ ($A \propto \exp\Lb - \mu
b\Rb$) as well as at large momentum transferred $Q_T$ ($A $ decreases as a
power of $Q_T$ as it follows from perturbative QCD). These improvement compared
to all previous attempts to build such models, allows us to claim, that the
experimental data are in accord with the prediction of CGC/saturation approach
while previously, based on similar models, we could only conclude that the DIS
data, perhaps, can be described by introducing the shadowing corrections at
small photon virtualities.
| arxiv topic:hep-ph |
arxiv_dataset-64931508.02644 | Crossover from $\beta$- to $\alpha$-relaxation in cooperative
facilitation dynamics
cond-mat.stat-mech
$\beta$ and $\alpha$ relaxation processes are dynamical scaling regimes of
glassy systems occurring on two separate time scales which both diverge as the
glass state is approached. We study here the crossover scaling from $\beta$- to
$\alpha$- relaxation in the cooperative facilitation scenario (CFS) and show
that it is quantitatively described, with no adjustable parameter, by the
leading order asymptotic formulas for scaling predicted by the mode-coupling
theory (MCT). These results establish: (i) the mutual universality of the MCT
and CFS, and (ii) the existence of a purely dynamic realization of MCT which is
distinct from the well established random-first order transition scenario for
disordered systems. Some implications of the emerging kinetic-static duality
are discussed.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-64941508.02744 | Accessible Proof of Standard Monomial Basis for Coordinatization of
Schubert Sets of Flags
math.CO math.RT
The main results of this paper are accessible with only basic linear algebra.
Given an increasing sequence of dimensions, a flag in a vector space is an
increasing sequence of subspaces with those dimensions. The set of all such
flags (the flag manifold) can be projectively coordinatized using products of
minors of a matrix. These products are indexed by tableaux on a Young diagram.
A basis of "standard monomials" for the vector space generated by such
projective coordinates over the entire flag manifold has long been known. A
Schubert variety is a subset of flags specified by a permutation. Lakshmibai,
Musili, and Seshadri gave a standard monomial basis for the smaller vector
space generated by the projective coordinates restricted to a Schubert variety.
Reiner and Shimozono made this theory more explicit by giving a straightening
algorithm for the products of the minors in terms of the right key of a Young
tableau. Since then, Willis introduced scanning tableaux as a more direct way
to obtain right keys. This paper uses scanning tableaux to give more-direct
proofs of the spanning and the linear independence of the standard monomials.
In the appendix it is noted that this basis is a weight basis for the dual of a
Demazure module for a Borel subgroup of GL(n). This paper contains a complete
proof that the characters of these modules (the key polynomials) can be
expressed as the sums of the weights for the tableaux used to index the
standard monomial bases.
| arxiv topic:math.CO math.RT |
arxiv_dataset-64951508.02844 | What is Holding Back Convnets for Detection?
cs.CV
Convolutional neural networks have recently shown excellent results in
general object detection and many other tasks. Albeit very effective, they
involve many user-defined design choices. In this paper we want to better
understand these choices by inspecting two key aspects "what did the network
learn?", and "what can the network learn?". We exploit new annotations
(Pascal3D+), to enable a new empirical analysis of the R-CNN detector. Despite
common belief, our results indicate that existing state-of-the-art convnet
architectures are not invariant to various appearance factors. In fact, all
considered networks have similar weak points which cannot be mitigated by
simply increasing the training data (architectural changes are needed). We show
that overall performance can improve when using image renderings for data
augmentation. We report the best known results on the Pascal3D+ detection and
view-point estimation tasks.
| arxiv topic:cs.CV |
arxiv_dataset-64961508.02944 | Topological phases of shaken quantum Ising lattices
cond-mat.quant-gas
The quantum compass model consists of a two-dimensional square spin lattice
where the orientation of the spin-spin interactions depends on the spatial
direction of the bonds. It has remarkable symmetry properties and the ground
state shows topological degeneracy. The implementation of the quantum compass
model in quantum simulation setups like ultracold atoms and trapped ions is far
from trivial, since spin interactions in those sytems typically are independent
of the spatial direction. Ising spin interactions, on the contrary, can be
induced and controlled in atomic setups with state-of-the art experimental
techniques. In this work, we show how the quantum compass model on a
rectangular lattice can be simulated by the use of the photon-assisted
tunneling induced by periodic drivings on a quantum Ising spin model. We
describe a procedure to adiabatically prepare one of the doubly-degenerate
ground states of this model by adiabatically ramping down a transverse magnetic
field, with surprising differences depending on the parity of the lattice size.
Exact diagonalizations confirm the validity of this approach for small
lattices. Specific implementations of this scheme are presented with ultracold
atoms in optical lattices in the Mott insulator regime, as well as with Rydberg
atoms.
| arxiv topic:cond-mat.quant-gas |
arxiv_dataset-64971508.03044 | Slowly rotating black hole solutions in Horndeski gravity
gr-qc astro-ph.CO hep-ph hep-th
We study black hole solutions at first order in the Hartle-Thorne
slow-rotation approximation in Horndeski gravity theories. We derive the
equations of motion including also cases where the scalar depends linearly on
time. In the Hartle-Thorne formalism, all first-order rotational corrections
are described by a single frame-dragging function. We show that the
frame-dragging function is exactly the same as in general relativity for all
known black hole solutions in shift symmetric Horndeski theories, with the
exception of theories with a linear coupling to the Gauss-Bonnet invariant. Our
results extend previous no-hair theorems for a broad class of Horndeski gravity
theories.
| arxiv topic:gr-qc astro-ph.CO hep-ph hep-th |
arxiv_dataset-64981508.03144 | Modification of Fox-Wolfram Moments for Hadron Colliders
hep-ph hep-ex
Collisions of composite particles impose an arbitrary boost in the
longitudinal direction on a given event. This implies that the centre-of-mass
frame at hadron colliders is undetermined for processes with missing energy in
the final state. This motivates the modification of the Fox-Wolfram moments
such that the moments for a given event are identical when viewed in the lab or
centre-of-mass frame of the beam. The resulting moments are invariant under
rotations in the plane transverse to the beam and boosts parallel to the beam.
These moments are then used to demonstrate improved signal separation in the
channel where the Higgs decays to two b-quarks while being produced in
association with a vector boson.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-64991508.03244 | Anomalous Lattice Dynamics of Mono-, Bi-, and Tri-layer WTe2
cond-mat.mes-hall cond-mat.mtrl-sci
Tungsten ditelluride (WTe2) is a layered material that exhibits excellent
magnetoresistance and thermoelectric behaviors, which are deeply related with
its distorted orthorhombic phase that may critically affect the lattice
dynamics. Here, for the first time, we present comprehensive characterization
of the Raman spectroscopic behavior of WTe2 from bulk to monolayer using
experimental and computational methods. We discover that mono and bi-layer WTe2
can be easily identified by Raman spectroscopy since double or single Raman
modes that are observed in higher-layer WTe2 are substantially suppressed in
the monolayer and bilayer WTe2, respectively. In addition, different from
hexagonal metal dichalcogenides, the frequency of in-plane mode of WTe2 remains
almost constant as the layer number decreases, while the other Raman modes
consistently blueshift. First-principles calculation validates the experiments
and reveals that the negligible shift of the mode is attributed to the lattice
vibration along the tungsten chains that make WTe2 structurally
one-dimensional.
| arxiv topic:cond-mat.mes-hall cond-mat.mtrl-sci |
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