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This paper presents a 125$\mu$W, area efficient (0.042mm2) 81dB DR, 8kS/s
current sensing ADC in 45nm CMOS capable of sensing sub-pA currents. Our
approach combines the transimpedance amplifier (TIA) and ADC into a unified
structure by folding a low-noise capacitive TIA into the first stage integrator
of a 2nd order Delta-Sigma modulator. The dominant DAC feedback noise is
mitigated by utilizing current scaling via slope modification by an integrator
and differentiator pair.
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We present the proof of renormalization of the Horava theory, in the
nonprojectable version. We obtain a form of the quantum action that exhibits a
manifest BRST-symmetry structure. Previous analysis have shown that the
divergences produced by irregular loops cancel completely between them. The
remaining divergences are local. The renormalization is achieved by using the
approach developed by Barvinsky et al. with the background-field formalism.
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Using exceptional theta correspondences we construct a family of Arthur
packets for the exceptional group of type D4, and establish the global Arthur
multiplicity formula.
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We consider a tachyon field whose Fourier components correspond to spatial
momenta with modulus smaller than the mass parameter. The plane wave solutions
have them a time evolution which is a real exponential. The field is quantized
and the solution of the eigenvalue problem for the Hamiltonian leads to the
evaluation of the vacuum expectation value of products of field operators. The
propagator turns out to be half-advanced and half-retarded. This completes the
proof [4] that the total propagator is the Wheeler Green function [4,7].
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In this paper, quantum mechanics on a circle with finite number of
{\alpha}-uniformly distributed points is discussed. The angle operator and
translation operator are defined. Using discrete angle representation, two
types of discrete angular momentum operators and Hermitian Hamiltonian on a
circle with d {\alpha}-distributed discrete angles are constructed. The energy
levels are computed for a free particle on a circle where the wave function is
defined in the d {\alpha}-distributed discrete angles.
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We extend recent analyses of stochastic effects in game dynamical learning to
cases of multi-player games, and to games defined on networked structures. By
means of an expansion in the noise strength we consider the weak-noise limit,
and present an analytical computation of spectral properties of fluctuations in
multi-player public good games. This extends existing work on two-player games.
In particular we show that coherent cycles may emerge driven by noise in the
adaptation dynamics. These phenomena are not too dissimilar from cyclic
strategy switching observed in experiments of behavioural game theory.
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We report the codiscovery of the spatially-resolved dust disk of the
Vega-like star HR 4796A. Images of the thermal dust emission at $\lambda = 18
\mu$m show an elongated structure approximately 200 AU in diameter surrounding
the central A0V star. The position angle of the disk, $30^{\circ} \pm
10^{\circ}$, is consistent to the position angle of the M companion star,
$225^{\circ}$, suggesting that the disk-binary system is being seen nearly
along its orbital plane. The surface brightness distribution of the disk is
consistent with the presence of an inner disk hole of approximately 50 AU
radius, as was originally suggested by Jura et al. on the basis of the infrared
spectrum. HR 4796 is a unique system among the Vega-like or $\beta$ Pictoris
stars in that the M star companion (a weak-emission T Tauri star) shows that
the system is relatively young, $\sim 8 \pm 3$ Myr. The inner disk hole may
provide evidence for coagulation of dust into larger bodies on a timescale
similar to that suggested for planet formation in the solar system.
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Correlated quantum systems feature a wide range of nontrivial effects
emerging from interactions between their constituting particles. In
nonequilibrium scenarios, these manifest in phenomena such as many-body
insulating states and anomalous scaling laws of currents of conserved
quantities, crucial for applications in quantum circuit technologies. In this
work we propose a giant rectification scheme based on the asymmetric interplay
between strong particle interactions and a tilted potential, each of which
induces an insulating state on their own. While for reverse bias both cooperate
and induce a strengthened insulator with an exponentially suppressed current,
for forward bias they compete generating conduction resonances; this leads to a
rectification coefficient of many orders of magnitude. We uncover the mechanism
underlying these resonances as enhanced coherences between energy eigenstates
occurring at avoided crossings in the system's bulk energy spectrum.
Furthermore, we demonstrate the complexity of the many-body nonequilibrium
conducting state through the emergence of enhanced density matrix impurity and
operator space entanglement entropy close to the resonances. Our proposal paves
the way for implementing a perfect diode in currently-available electronic and
quantum simulation platforms.
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In this paper, we propose Energy-efficient Adaptive Scheme for Transmission
(EAST) in WSNs. EAST is IEEE 802.15.4 standard compliant. In this approach,
open-loop is used for temperature-aware link quality estimation and
compensation. Whereas, closed-loop feedback helps to divide network into three
logical regions to minimize overhead of control packets on basis of Threshold
transmitter power loss (RSSIloss) for each region and current number of
neighbor nodes that help to adapt transmit power according to link quality
changes due to temperature variation. Simulation results show that propose
scheme; EAST effectively adapts transmission power to changing link quality
with less control packets overhead and energy consumption compared to classical
approach with single region in which maximum transmitter power assigned to
compensate temperature variation.
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We prove a hydrodynamic limit for the totally asymmetric simple exclusion
process with spatially inhomogeneous jump rates given by a speed function that
may admit discontinuities. The limiting density profiles are described with a
variational formula. This formula enables us to compute explicit density
profiles even though we have no information about the invariant distributions
of the process. In the case of a two-phase flow for which a suitable p.d.e.
theory has been developed we also observe that the limit profiles are entropy
solutions of the corresponding scalar conservation law with a discontinuous
speed function.
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We study the synchronization of coupled dynamical systems on a variety of
networks. The dynamics is governed by a local nonlinear map or flow for each
node of the network and couplings connecting different nodes via the links of
the network. For small coupling strengths nodes show turbulent behavior but
form synchronized clusters as coupling increases. When nodes show synchronized
behaviour, we observe two interesting phenomena. First, there are some nodes of
the floating type that show intermittent behaviour between getting attached to
some clusters and evolving independently. Secondly, we identify two different
ways of cluster formation, namely self-organized clusters which have mostly
intra-cluster couplings and driven clusters which have mostly inter-cluster
couplings.
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For a connected reductive group $ G $ defined over a number field $ k $, we
construct the Schwartz space $ \mathcal{S}(G(k)\backslash G(\mathbb{A})) $.
This space is an adelic version of Casselman's Schwartz space $
\mathcal{S}(\Gamma\backslash G_\infty) $, where $ \Gamma $ is a discrete
subgroup of $ G_\infty:=\prod_{v\in V_\infty}G(k_v) $. We study the space of
tempered distributions $ \mathcal{S}(G(k)\backslash G(\mathbb A))' $ and
investigate applications to automorphic forms on $ G(\mathbb A) $. In
particular, we study the representation $ \left(r',\mathcal{S}(G(k)\backslash
G(\mathbb{A}))'\right) $ contragredient to the right regular representation $
(r,\mathcal{S}(G(k)\backslash G(\mathbb{A}))) $ of $ G(\mathbb{A}) $ and
describe the closed irreducible admissible subrepresentations of $
\mathcal{S}(G(k)\backslash G(\mathbb{A}))' $ assuming that $ G $ is semisimple.
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The ALICE experiment features multiple particle identification systems. The
measurement of the identified charged hadron $p_{t}$ spectra in proton-proton
collisions at $\sqrt{s}=900$ GeV will be discussed. In the central rapidity
region ($|\eta|<0.9$) particle identification and tracking are performed using
the Inner Tracking System (ITS), which is the closest detector to the beam
axis, the Time Projection Chamber (TPC) and a dedicated time-of-flight system
(TOF). Particles are mainly identified using the energy loss signal in the ITS
and TPC. In addition, the information from TOF is used to identify hadrons at
higher momenta. Finally, the kink topology of the weak decay of charged kaons
provides an alternative method to extract the transverse momentum spectra of
charged kaons. This combination allows to track and identify charged hadrons in
the transverse momentum ($p_{t}$) range from 100 MeV/c up to 2.5 GeV/$c$.
Mesons containing strange quarks (\kos, $\phi$) and both singly and doubly
strange baryons (\lam, \lambar, and \xip + \xim) are identified by their decay
topology inside the TPC detector. Results obtained with the various
identification tools above described and a comparison with theoretical models
and previously published data will be presented.
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Generation and manipulation of many-body entangled states is of considerable
interest, for applications in quantum simulation or sensing, for example.
Measurement and verification of the resulting many-body state presents a
formidable challenge, however, which can be simplified by multiplexed readout
using shared measurement resources. In this work, we analyze and demonstrate
state retrodiction for a system of optomechanical oscillators coupled to a
single-mode optical cavity. Coupling to the shared cavity field facilitates
simultaneous optical measurement of the oscillators' transient dynamics at
distinct frequencies. Optimal estimators for the oscillators' initial state can
be defined as a set of linear matched filters, derived from a detailed model
for the detected homodyne signal. We find that the optimal state estimate for
optomechanical retrodiction is obtained from high-cooperativity measurements,
reaching estimate sensitivity at the Standard Quantum Limit (SQL). Simultaneous
estimation of the state of multiple oscillators places additional limits on the
estimate precision, due to the diffusive noise each oscillator adds to the
optomechanical signal. However, we show that the sensitivity of simultaneous
multi-mode state retrodiction reaches the SQL for sufficiently well-resolved
oscillators. Finally, an experimental demonstration of two-mode retrodiction is
presented, which requires further accounting for technical fluctuations of the
oscillator frequency.
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Identification of features is a critical task in microbiome studies that is
complicated by the fact that microbial data are high dimensional and
heterogeneous. Masked by the complexity of the data, the problem of separating
signals from noise becomes challenging and troublesome. For instance, when
performing differential abundance tests, multiple testing adjustments tend to
be overconservative, as the probability of a type I error (false positive)
increases dramatically with the large numbers of hypotheses. Moreover, the
grouping effect of interest can be obscured by heterogeneity. These factors can
incorrectly lead to the conclusion that there are no differences in the
microbiome compositions. We translate and represent the problem of identifying
differential features as a dynamic layout of separating the signal from its
random background. We propose progressive permutation as a method to achieve
this process and show converging patterns. More specifically, we progressively
permute the grouping factor labels of the microbiome samples and perform
multiple differential abundance tests in each scenario. We then compare the
signal strength of the top features from the original data with their
performance in permutations, and observe an apparent decreasing trend if these
top features are true positives identified from the data. We have developed
this into a user-friendly RShiny tool and R package, which consist of functions
that can convey the overall association between the microbiome and the grouping
factor, rank the robustness of the discovered microbes, and list the
discoveries, their effect sizes, and individual abundances.
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Rare-earth-based triangular-lattice magnets provide the fertile ground to
explore the exotic quantum magnetic state. Herein, we report a new family of
RE-based triangular-lattice magnets Ba6RE2Ti4O17(RE= rare earth ions)
crystallized into the hexagonal structure with space group of P63 mmc, where
magnetic rare earth ions form an ideal triangular lattice within the ab-plane
and stack in an AA -type fashion along the c-axis. The low-temperature magnetic
susceptibility results reveal all the serial compounds have the dominant
antiferromagnetic interactions and an absence of magnetic ordering down to 1.8
K. The magnetization and electron spin resonance results indicate distinct
magnetic anisotropy for the compounds with different RE ions. Moreover,
Ba6Nd2Ti4O17 single crystal is successfully grown and it exhibits strong Ising
like anisotropy with magnetic easy-axis perpendicular to the triangle-lattice
plane, being a candidate to explore quantum spin liquid state with dominant
Ising-type interaction.
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We analyze the performance of a variant of Newton method with quadratic
regularization for solving composite convex minimization problems. At each step
of our method, we choose regularization parameter proportional to a certain
power of the gradient norm at the current point. We introduce a family of
problem classes characterized by H\"older continuity of either the second or
third derivative. Then we present the method with a simple adaptive search
procedure allowing an automatic adjustment to the problem class with the best
global complexity bounds, without knowing specific parameters of the problem.
In particular, for the class of functions with Lipschitz continuous third
derivative, we get the global $O(1/k^3)$ rate, which was previously attributed
to third-order tensor methods. When the objective function is uniformly convex,
we justify an automatic acceleration of our scheme, resulting in a faster
global rate and local superlinear convergence. The switching between the
different rates (sublinear, linear, and superlinear) is automatic. Again, for
that, no a priori knowledge of parameters is needed.
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Measurements of the energy spectrum and of the vortex-density fluctuation
spectrum in superfluid turbulence seem to contradict each other. Using a
numerical model, we show that at each instance of time the total vortex line
density can be decomposed into two parts: one formed by metastable bundles of
coherent vortices, and one in which the vortices are randomly oriented. We show
that the former is responsible for the observed Kolmogorov energy spectrum, and
the latter for the spectrum of the vortex line density fluctuations.
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Nearby interstellar clouds at high Galactic latitudes are ideal objects in
which the interaction of interstellar dust with photons from the
well-characterized interstellar radiation field can be studied. Scattering and
UV-excited photoluminescence at optical wavelengths as well as thermal emission
at mid- and far-infrared wavelengths are observable manifestations of such
interactions. Here we report initial results from an optical imaging survey of
optically thin high-Galactic-latitude clouds, which is designed to study the
surface brightness, structure, and spectral energy distribution of these
objects. The primary aim of this paper is to study the extended red emission
(ERE) that has been reported at high Galactic latitudes in earlier
investigations and which is attributed to ultraviolet-excited photoluminescence
of an as yet unidentified component of interstellar dust. We find strong
evidence for dust emission in the form of a broad (>1000 A FWHM) ERE band with
peak emission near 600 nm wavelength and peak intensity of ~ 5x10^-9 (erg cm^-2
s^-1 A^-1 sr^-1) in optically-thin clouds. This amounts to about 30% of the
total optical surface brightness of these clouds, the remainder being
consistent with expectations for dust-scattered light. This supports claims for
the ubiquitous presence of the ERE carrier throughout the diffuse interstellar
medium of the Milky Way Galaxy. We suggest that the ERE carrier is involved in
the radiative processing of about 20% to 30% of the dust-absorbed UV/optical
luminosity of the Milky Way galaxy, with the bulk of this energy being emitted
in the near- to mid-infrared spectral regions.
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We prove in this paper the global Lorentz estimate in term of
fractional-maximal function for gradient of weak solutions to a class of
p-Laplace elliptic equations containing a non-negative Schr\"odinger potential
which belongs to reverse H\"older classes. In particular, this class of
p-Laplace operator includes both degenerate and non-degenerate cases. The
interesting idea is to use an efficient approach based on the level-set
inequality related to the distribution function in harmonic analysis.
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Since the end of 90s till today when all the elements confirming Georgian
State System have practically been established, budget system and policy
remains as the most difficult Georgian macroeconomics challenge and even still
half-and-half unsolved problem. One side of the fiscal policy is quite
crucially formulated and administrative Tax Code, and the other side is the
weak, unmanaged and incomplete law on Budget System. According to the
above-mentioned the elaboration and adoption of the Budget Code having equal
force as Tax Code is necessary by which the following are to be determined:
excellence of government responsibility when it will not perform the budget
obligations specified by the law permanently; the rights and responsibilities
of the state, the optimal distribution of the funds mobilized by the tax
towards each member of the society. For optimization of the budget system
effective correlation between the state, regional and local budgets revenues
and expenditures is particularly important as the social-economic development
of the regions and territorial units of the country is impossible without the
financial relations. For it the just differentiation of tax base in the section
of state, regional and local budgets and transfers system for support of the
budgets of the territorial units from the central budget are necessary. Solving
the most part of these problems is possible by the adoption of the budget code
which, in our opinion, is to be considered as the closest decisive task for the
current legislative and executive authority.
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Flow measurements of multi-strange baryons from Au + Au collisions at RHIC
energies demonstrate that collectivity develops before hadronization, among
partons. To pin down the partonic EOS of matter produced at RHIC, the status of
thermalization in such collisions has to be addressed. We propose to measure
collective flow of heavy-flavor quarks, e.g. charm quarks, as an indicator of
thermalization of light flavors ($u,d,s$). The completion of the time of flight
barrel and the proposed upgrade with a $\mu$Vertex detector for heavy-flavor
identification in STAR are well suited for achieving these goals.
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In this study, the effect of online cooperative learning homework practices
on academic success of students is searched. The experience group of the
research consists of 58 students from Anadolu University Education Faculty
Education of Computer and Instruction Technology Section. Students in A section
are taken to traditional method by neutral appointment; those in B section are
taken to online homework practice method. In each class consisting of 29
people, it's decided that 14 students prepare their homework individually; the
rest 15 students prepare their homework with cooperative as triple groups. It's
students' own choice to prepare their homework individually or cooperatively.
There has been a success scale at the end of the teaching period. According to
research results, there isn't statistically considerable difference between
students who attend traditional homework practices and online homework
practices. According to research results, there isn't statistically
considerable difference between students who attend individual homework
practices and cooperative homework practices. The academic success of the
students who attend online-based individual homework practices is higher than
traditional individual and online based cooperative learning homework
practices.
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We introduce a non-linear extension of Proca's field theory for massive
vector (spin $1$) bosons. The associated relativistic nonlinear wave equation
is related to recently advanced nonlinear extensions of the Schroedinger,
Dirac, and Klein-Gordon equations inspired on the non-extensive generalized
thermostatistics. This is a theoretical framework that has been applied in
recent years to several problems in nuclear and particle physics, gravitational
physics, and quantum field theory. The nonlinear Proca equation investigated
here has a power-law nonlinearity characterized by a real parameter $q$
(formally corresponding to the Tsallis entropic parameter) in such a way that
the standard linear Proca wave equation is recovered in the limit $q
\rightarrow 1$. We derive the nonlinear Proca equation from a Lagrangian that,
besides the usual vectorial field $\Psi^{\mu}(\vec{x},t)$, involves an
additional field $\Phi^{\mu}(\vec{x},t)$. We obtain exact time dependent
soliton-like solutions for these fields having the form of a $q$-plane wave,
and show that both field equations lead to the relativistic energy-momentum
relation $E^{2} = p^{2}c^{2} + m^{2}c^{4}$ for all values of $q$. This suggests
that the present nonlinear theory constitutes a new field theoretical
representation of particle dynamics. In the limit of massless particles the
present $q$-generalized Proca theory reduces to Maxwell electromagnetism, and
the $q$-plane waves yield localized, transverse solutions of Maxwell equations.
Physical consequences and possible applications are discussed.
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The summation of all rainbow diagrams in QED in a strong magnetic field leads
to a dynamical electron mass on the light-cone. Further contributions to this
summation however can cause problems with light-cone singularities. It is shown
that these problems are generally avoided by applying the point-splitting
regularization to every diagram. The possibility of implementing this procedure
into the Lagrangian of the theory is discussed.
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We investigate the strongly correlated ion dynamics and the degree of
coupling achievable in the evolution of freely expanding ultracold neutral
plasmas. We demonstrate that the ionic Coulomb coupling parameter $\Gamma_{\rm
i}$ increases considerably in later stages of the expansion, reaching the
strongly coupled regime despite the well-known initial drop of $\Gamma_{\rm i}$
to order unity due to disorder-induced heating. Furthermore, we formulate a
suitable measure of correlation and show th at $\Gamma_{\rm i}$ calculated from
the ionic temperature and density reflects the degree of order in the system if
it is sufficiently close to a quasisteady state. At later times, however, the
expansion of the plasma cloud becomes faster than the relaxation of
correlations, and the system does not reach thermodynamic equilibrium anymore.
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This paper describes a new way to predict real time series using
complex-valued elements. An example is given in the case of the short-term
probabilistic global solar irradiance forecasts with measurement as real part
and an estimate of the volatility as imaginary part. A simple complex
autoregressive model is tested with data collected in Corsica island (France).
Results show that, even if this approach is simple to set up and requires very
little resource and data, both deterministic and probabilistic forecasts
generated by this model are in agreement with experimental data (root mean
square error ranging from 0.196 to 0.325 considering all studied horizons). In
addition, it exhibits sometimes a better accuracy than classical models like
Gaussian process, bootstrap methodology or even more sophisticated model like
quantile regression. The number of models that it is possible to build by
generating complex-valued time series is substantial. Indeed, by using
exogenous or ordinal variables and computed quantities coupled with complex (or
multi-complex) numbers, many studies and many fields of physics could benefit
from this methodology and from the many models that result from it.
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Motivated by questions asked by Erdos, we prove that any set
$A\subset{\mathbb N}$ with positive upper density contains, for any
$k\in{\mathbb N}$, a sumset $B_1+\cdots+B_k$, where
$B_1,\dots,B_k\subset{\mathbb N}$ are infinite. Our proof uses ergodic theory
and relies on structural results for measure preserving systems. Our techniques
are new, even for the previously known case of $k=2$.
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Using the graphical method developed in hep-th/9908082, we obtain the full
curve corresponding to the hyperk\"ahler quotient from the extended E_7 Dynkin
diagram. As in the E_6 case discussed in the same paper above, the resulting
curve is the same as the one obtained by Minahan and Nemeschansky. Our results
seem to indicate that it is possible to define a generalized Coulomb branch
such that four dimensional mirror symmetry would act by interchanging the
generalized Coulomb branch with the Higgs branch of the dual theory. To
understand these phenomena, we discuss mirror symmetry and F-theory
compactifications probed by D3 branes.
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The article presents some aspects on the use of computer in teaching general
relativity for undergraduate students with some experience in computer
manipulation. The article presents some simple algebraic programming (in
REDUCE+EXCALC package) procedures for obtaining and the study of some exact
solutions of the Einstein equations in order to convince a dedicated student in
general relativity about the utility of a computer algebra system.
|
While there have been many developments in computational probes of both
strongly-correlated molecular systems and machine-learning accelerated
molecular dynamics, there remains a significant gap in capabilities between
them, where it is necessary to describe the accurate electronic structure over
timescales in which atoms move. We describe a practical approach to bridge
these fields by interpolating the correlated many-electron state through
chemical space, whilst avoiding the exponential complexity of these underlying
states. With a small number of accurate correlated wave function calculations
as a training set, we demonstrate provable convergence to near-exact potential
energy surfaces for subsequent dynamics with propagation of a valid many-body
wave function and inference of its variational energy at all points, whilst
retaining a mean-field computational scaling. This represents a profoundly
different paradigm to the direct interpolation of properties through chemical
space in established machine-learning approaches. It benefits from access to
all electronic properties of interest from the same model without relying on
local descriptors, and demonstrates improved performance compared to the direct
training on energies themselves. We combine this with modern
systematically-improvable electronic structure methods to resolve the molecular
dynamics for a number of correlated electron problems, including the proton
dynamics of a Zundel cation trajectory, where we highlight the qualitative
improvement from traditional machine learning or ab initio dynamics on
mean-field surfaces.
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A scalar-tensor theory of gravity is formulated in which $G$ and particle
masses are allowed to vary. The theory yields a globally static cosmological
model with no evolutionary timescales, no cosmological coincidences, and no
flatness and horizon `problems'. It can be shown that the energy densities of
dark energy ($\rho_{DE}$) and non-relativistic baryons and dark matter
($\rho_{M}$) are related by $\rho_{DE}=2\rho_{M}$, in agreement with current
observations, if DE is associated with the canonical kinetic and potential
energy densities of the scalar fields. Under general assumptions, the model
favors light fermionic dark matter candidates (e.g., sterile neutrinos). The
main observed features of the CMB are naturally explained in this model,
including the spectral flatness of its perturbations on the largest angular
scales, and the observed adiabatic and gaussian nature of density
perturbations. More generally, we show that many of the cosmological
observables, normally attributed to the dynamics of expanding space, could be
of kinematic origin. In gravitationally bound systems, the values of G and
particle masses spontaneously freeze out by a symmetry breaking of the
underlying conformal symmetry, and the theory reduces to standard general
relativity (with, e.g., all solar system tests satisfied).
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During the past several years, experiments at RHIC have established that a
dense partonic medium is produced in Au+Au collisions at sqrt(s)=200 GeV.
Subsequently, a primary goal of analysis has been to understand and
characterize the dynamics underlying this new form of matter. Among the many
probes available, the measurements with respect to the reaction plane has
proven to be crucial to our understanding of a wide range of topics, from the
hydrodynamics of the initial expansion of the collision region to high-pt jet
quenching phenomena. Few tools have the ability to shed light on such a wide
variety of observables as the reacion plane. In this article, we discuss recent
PHENIX measurements with respect to the reaction plane, and the implications
for understanding the underlying physics of RHIC collisions.
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We construct a superfield formulation for non-relativistic
Chern-Simons-Matter theories with manifest dynamical supersymmetry. By
eliminating all the auxiliary fields, we show that the simple action reduces to
the one obtained by taking non-relativistic limit from the relativistic
Chern-Simons-Matter theory proposed in the literature. As a further
application, we give a manifestly supersymmetric derivation of the
non-relativistic ABJM theory.
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Dawning neutron physics was more complex than one might expect. The chance
that the neutron comprised a proton and an electron was diffusely taken into
account after the discovery of the neutron. Moreover, uncertainties persisted
about the composition of beryllium radiation until it was realized that the
latter comprised both neutrons and gamma-rays. The interaction of neutrons with
matter and nuclei was soon investigated. Both a spatial symmetry, a symmetry of
charge, and a symmetry in the nuclear reactions soon emerged. The relation of
negative beta-decay to the neutron abundance in nuclei was moreover reviewed.
Positive beta-radioactivity induced by alpha-particles was eventually
announced, having been foreseen some weeks before. Accelerated deutons and
protons shortly afterwards revealed to be efficient in inducing radioactivity.
The physics institute in Rome got ready to start research on neutrons, but
apparently it only planned to go through alpha-induced radioactivity, at first.
If so, it is then plausible that some new results achieved by foreign
laboratories eventually bent Fermi to neutrons. Fermi's discovery of
neutron-induced radioactivity is reviewed with regard to investigations then
current, once more showing simplicity as a distinctive trait of Fermi's way of
doing physics.
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We introduce a chain complex associated to a Liouville domain $(\overline{W},
d\lambda)$ whose boundary $Y$ admits a Boothby--Wang contact form (i.e. is a
prequantization space). The differential counts cascades of Floer solutions in
the completion $W$ of $\overline{W}$, in the spirit of Morse--Bott homology (as
in work of Bourgeois, Frauenfelder arXiv:math/0309373 and Bourgeois-Oancea
arXiv:0704.1039). The homology of this complex is the symplectic homology of
the completion $W$.
We identify a class of simple cascades and show that their moduli spaces are
cut out transversely for generic choice of auxiliary data. If $X$ is obtained
by collapsing the boundary along Reeb orbits and $\Sigma$ is the quotient of
$Y$ by the $S^1$-action induced by the Reeb flow, we also establish
transversality for certain moduli spaces of holomorphic spheres in $X$ and in
$\Sigma$.
Finally, under monotonicity assumptions on $X$ and $\Sigma$, we show that for
generic data, the differential in our chain complex counts elements of moduli
spaces that are transverse. Furthermore, by some index estimates, we show that
very few combinatorial types of cascades can appear in the differential.
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This paper provides full sky maps of foreground emission in all WMAP
channels, with very low residual contamination from the Cosmic Microwave
Background (CMB) anisotropies and controlled level of instrumental noise.
Foreground maps are obtained by subtraction of a properly filtered CMB map,
obtained from linear combinations of needlet-based representations of all WMAP
observations and of a 100-micron map. The error in the reconstructed foreground
maps on large scales is significantly lower than the original error due to CMB
contamination, while remaining of the order of the original WMAP noise on small
scales. The level of the noise is estimated, which permits to implement local
filters for maximising the local signal to noise ratio. An example of such
filtering, which reduces the small scale noise using latitude dependent filters
is implemented. This enhances significantly the contrast of galactic emission,
in particular on intermediate angular scales and at intermediate galactic
latitude. The clean WMAP foreground maps can be used to study the galactic
interstellar medium, in particular for the highest frequency channels for which
the proper subtraction of CMB contamination is mandatory. The foregrounds maps
can be downloaded from a dedicated web site.
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We propose an object detector for top-view grid maps which is additionally
trained to generate an enriched version of its input. Our goal in the joint
model is to improve generalization by regularizing towards structural knowledge
in form of a map fused from multiple adjacent range sensor measurements. This
training data can be generated in an automatic fashion, thus does not require
manual annotations. We present an evidential framework to generate training
data, investigate different model architectures and show that predicting
enriched inputs as an additional task can improve object detection performance.
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In this paper we give a lower bound for the codimension of the
Andreotti-Mayer loci in the moduli space of principally polarized complex
abelian varieties. We also present a conjecture on this codimension.
|
Personalization in Federated Learning (FL) aims to modify a collaboratively
trained global model according to each client. Current approaches to
personalization in FL are at a coarse granularity, i.e. all the input instances
of a client use the same personalized model. This ignores the fact that some
instances are more accurately handled by the global model due to better
generalizability. To address this challenge, this work proposes Flow, a
fine-grained stateless personalized FL approach. Flow creates dynamic
personalized models by learning a routing mechanism that determines whether an
input instance prefers the local parameters or its global counterpart. Thus,
Flow introduces per-instance routing in addition to leveraging per-client
personalization to improve accuracies at each client. Further, Flow is
stateless which makes it unnecessary for a client to retain its personalized
state across FL rounds. This makes Flow practical for large-scale FL settings
and friendly to newly joined clients. Evaluations on Stackoverflow, Reddit, and
EMNIST datasets demonstrate the superiority in prediction accuracy of Flow over
state-of-the-art non-personalized and only per-client personalized approaches
to FL.
|
We initiate the study of stochastic optimization with oblivious noise,
broadly generalizing the standard heavy-tailed noise setup. In our setting, in
addition to random observation noise, the stochastic gradient may be subject to
independent oblivious noise, which may not have bounded moments and is not
necessarily centered. Specifically, we assume access to a noisy oracle for the
stochastic gradient of $f$ at $x$, which returns a vector $\nabla f(\gamma, x)
+ \xi$, where $\gamma$ is the bounded variance observation noise and $\xi$ is
the oblivious noise that is independent of $\gamma$ and $x$. The only
assumption we make on the oblivious noise $\xi$ is that $\mathbf{Pr}[\xi = 0]
\ge \alpha$ for some $\alpha \in (0, 1)$. In this setting, it is not
information-theoretically possible to recover a single solution close to the
target when the fraction of inliers $\alpha$ is less than $1/2$. Our main
result is an efficient list-decodable learner that recovers a small list of
candidates, at least one of which is close to the true solution. On the other
hand, if $\alpha = 1-\epsilon$, where $0< \epsilon < 1/2$ is sufficiently small
constant, the algorithm recovers a single solution. Along the way, we develop a
rejection-sampling-based algorithm to perform noisy location estimation, which
may be of independent interest.
|
In this letter, we develop a model formalism to study the structure of a
relativistic, viscous, optically thin, advective accretion flow around a
rotating black hole in presence of radiative coolings. We use this model to
examine the physical parameters of the Ultra-luminous X-ray sources (ULXs),
namely mass ($M_{\rm BH}$), spin ($a_{\rm k}$) and accretion rate (${\dot m}$),
respectively. While doing this, we adopt a recently developed effective
potential to mimic the spacetime geometry around the rotating black holes. We
solve the governing equations to obtain the shock induced global accretion
solutions in terms of ${\dot m}$ and viscosity parameter ($\alpha$). Using
shock properties, we compute the Quasi-periodic Oscillation (QPO) frequency
($\nu_{\rm QPO}$) of the post-shock matter (equivalently post-shock corona,
hereafter PSC) pragmatically, when the shock front exhibits Quasi-periodic
variations. We also calculate the luminosity of the entire disc for these shock
solutions. Employing our results, we find that the present formalism is
potentially promising to account the observed $\nu_{\rm QPO}$ and bolometric
luminosity ($L_{\rm bol}$) of a well studied ULX source IC 342 X-1. Our
findings further imply that the central source of IC 342 X-1 seems to be
rapidly rotating and accretes matter at super-Eddington accretion rate provided
IC 342 X-1 harbors a massive stellar mass black hole ($M_{\rm BH} < 100
M_\odot$) as indicated by the previous studies.
|
It has been argued in previous papers that an ion-proton plasma is formed at
the polar caps of neutron stars with positive polar-cap corotational charge
density. The present paper does not offer a theory of the development of
turbulence from the unstable Langmuir modes that grow in the outward
accelerated plasma, but attempts to describe in qualitative terms the factors
relevant to the emission of polarized radiation at frequencies below 1 - 10
GHz. The work of Karastergiou and Johnston is of particular importance in this
respect because it demonstrates in high-resolution measurements of the profiles
of 17 pulsars that the relative phase retardation between the O- and E-modes of
the plasma is no greater than of the order of pi. Provided the source of the
radiation is at low altitudes, as favoured by recent observations, this order
of retardation is possible only for a plasma of baryonic-mass particles.
|
A Monte Carlo simulator is presented to reproduce data of nucleus-nucleus
interactions at high energies. The program is designed in a microscopic point
of view, where the cascade approach is applied. Moreover, each nucleon from
both the target and the projectile is followed up on the time scale along the
collision time. The effect of the mean field that depends on the nuclear
density is considered. Elastic and inelastic scattering are allowed for the
nucleon binary collisions during the cascade according to their center of mass
energies. Particle productions are studied through the fragmentation of strings
and sub-strings, which may be formed due to the color field between the
interacting quarks rather than the gluing interactions. The predictions of the
Monte Carlo are fairly compared with the recent CERN data of p-32S and 32S-32S
collisions at 200 A GeV incident energy.
|
Freezing or solidification of impacting droplets is omnipresent in nature and
technology, be it a rain droplet falling on a supercooled surface, be it in
inkjet printing where often molten wax is used, be it in added manufacturing or
in metal production processes or in extreme ultraviolet lithography (EUV) for
the chip production where molten tin is used to generate the EUV radiation. For
many of these industrial applications, a detailed understanding of the
solidification process is essential. Here, by adopting a totally new optical
technique in the context of freezing, namely TIR (Total-Internal-Reflection),
we elucidate the freezing kinetics during the solidification of a droplet while
it impacts on an undercooled surface. We show for the first time that at
sufficiently high undercooling a peculiar freezing morphology exists that
involves sequential advection of frozen fronts from the centre of the droplet
to its boundaries. This phenomenon is examined by combining elements of
classical nucleation theory to the large scale hydrodynamics on the droplet
scale, bringing together two subfields which traditionally have been quite
separated. Furthermore, we report a peculiar self-peeling phenomenon of a
frozen splat that is driven by the existence of a transient crystalline state
during solidification.
|
Quantum entanglement associated with transverse wave vectors of down
conversion photons is investigated based on the Schmidt decomposition method.
We show that transverse entanglement involves two variables: orbital angular
momentum and transverse frequency. We show that in the monochromatic limit high
values of entanglement are closely controlled by a single parameter resulting
from the competition between (transverse) momentum conservation and
longitudinal phase matching. We examine the features of the Schmidt eigenmodes,
and indicate how entanglement can be enhanced by suitable mode selection
methods.
|
In this paper we present 43 new inequalities related to integer part and
fractional part.
|
This paper develops on-line inference for the multivariate local level model,
with the focus being placed on covariance estimation of the innovations. We
assess the application of the inverse Wishart prior distribution in this
context and find it too restrictive since the serial correlation structure of
the observation and state innovations is forced to be the same. We generalize
the inverse Wishart distribution to allow for a more convenient correlation
structure, but still retaining approximate conjugacy. We prove some relevant
results for the new distribution and we develop approximate Bayesian inference,
which allows simultaneous forecasting of time series data and estimation of the
covariance of the innovations of the model. We provide results on the steady
state of the level of the time series, which are deployed to achieve
computational savings. Using Monte Carlo experiments, we compare the proposed
methodology with existing estimation procedures. An example with real data
consisting of production data from an industrial process is given.
|
Physical Ising machines rely on nature to guide a dynamical system towards an
optimal state which can be read out as a heuristical solution to a
combinatorial optimization problem. Such designs that use nature as a computing
mechanism can lead to higher performance and/or lower operation costs and hence
have attracted research and prototyping efforts from industry and academia.
Quantum annealers are a prominent example of such efforts. However, some
physics-centric Ising machines require stringent operating conditions that
result in significant bulk and energy budget. Such disadvantages may be
acceptable if these designs provide some significant intrinsic advantages at a
much larger scale in the future, which remains to be seen. But for now,
integrated electronic designs of Ising machines allow more immediate
applications. We propose one such design that uses bistable nodes, coupled with
programmable and variable strengths. The design is fully CMOS compatible for
chip-scale applications and demonstrates competitive solution quality and
significantly superior execution time and energy.
|
The resolvent formulation of McKeon & Sharma (2010) is applied to supersonic
turbulent boundary layers to study the validity of Morkovin's hypothesis, which
postulates that high-speed turbulence structures in zero pressure-gradient
turbulent boundary layers remain largely the same as its incompressible
counterpart. Supersonic zero-pressure-gradient turbulent boundary layers with
adiabatic wall boundary conditions at Mach numbers ranging from 2 to 4 are
considered. Resolvent analysis highlights two distinct regions of the
supersonic turbulent boundary layer in the wave parameter space: the relatively
supersonic region and the relatively subsonic region. In the relatively
supersonic region, where the flow is supersonic relative to the freestream,
resolvent modes display structures consistent with Mach wave radiation that are
absent in the incompressible regime. In the relatively subsonic region, we show
that the low-rank approximation of the resolvent operator is an effective
approximation of the full system and that the response modes predicted by the
model exhibit universal and geometrically self-similar behaviour via a
transformation given by the semi-local scaling. Moreover, with the semi-local
scaling, we show that the resolvent modes follow the same scaling law as their
incompressible counterparts in this region, which has implications for
modelling and the prediction of turbulent high-speed wall-bounded flows. We
also show that the thermodynamic variables exhibit similar mode shapes to the
streamwise velocity modes, supporting the strong Reynolds analogy. Finally, we
demonstrate that the principal resolvent modes can be used to capture the
energy distribution between momentum and thermodynamic fluctuations.
|
In this paper we report a new PNP Surface Accumulation Layer Transistor
(SALTran) on SOI which uses the concept of surface accumulation of holes near
the emitter contact to significantly improve the current gain. Using
two-dimensional simulation, we have evaluated the performance of the proposed
device in detail by comparing its characteristics with those of the previously
published conventional PNP lateral bipolar transistor (LBT) structure. From our
simulation results it is observed that depending on the choice of the emitter
doping and the emitter length, the proposed SALTran exhibits a current gain
enhancement of around 20 times that of the compatible lateral bipolar
transistor without deteriorating the cut-off frequency. We have discussed the
reasons for the improved performance of the SALTran based on our detailed
simulation results.
|
We investigate the influence of the electron-phonon interaction on the decay
dynamics of a quantum dot coupled to an optical microcavity. We show that the
electron-phonon interaction has important consequences on the dynamics,
especially when the quantum dot and cavity are tuned out of resonance, in which
case the phonons may add or remove energy leading to an effective non-resonant
coupling between quantum dot and cavity. The system is investigated using two
different theoretical approaches: (i) a second-order expansion in the bare
phonon coupling constant, and (ii) an expansion in a polaron-photon coupling
constant, arising from the polaron transformation which allows an accurate
description at high temperatures. In the low temperature regime we find
excellent agreement between the two approaches. An extensive study of the
quantum dot decay dynamics is performed, where important parameter dependencies
are covered. We find that in general the electron-phonon interaction gives rise
to a greatly increased bandwidth of the coupling between quantum dot and
cavity. At low temperature an asymmetry in the quantum dot decay rate is
observed, leading to a faster decay when the quantum dot has a larger energy
than to the cavity. We explain this as due to the absence of phonon absorption
processes. Furthermore, we derive approximate analytical expressions for the
quantum dot decay rate, applicable when the cavity can be adiabatically
eliminated. The expressions lead to a clear interpretation of the physics and
emphasizes the important role played by the effective phonon density,
describing the availability of phonons for scattering, in quantum dot decay
dynamics. Based on the analytical expressions we present the parameter regimes
where phonon effects are expected to be important. Also, we include all
technical developments in appendices.
|
The two-dimensional scaling Ising model in a magnetic field at critical
temperature is integrable and possesses eight stable particles A_i (i=1,...,8)
with different masses. The heaviest five lie above threshold and owe their
stability to integrability. We use form factor perturbation theory to compute
the decay widths of the first two particles above threshold when integrability
is broken by a small deviation from the critical temperature. The lifetime
ratio t_4/t_5 is found to be 0.233; the particle A_5 decays at 47% in the
channel A_1A_1 and for the remaining fraction in the channel A_1A_2. The
increase of the lifetime with the mass, a feature which can be expected in two
dimensions from phase space considerations, is in this model further enhanced
by the dynamics.
|
Quantum corrections to the Schwarzschild metric generated by loop diagrams
have been considered by Bjerrum-Bohr, Donoghue, and Holstein (BHD) [Phys. Rev.
D68, 084005 (2003)], and Khriplovich and Kirilin (KK) [J. Exp. Theor. Phys. 98,
1063 (2004)]. Though the same field variables in a covariant gauge are used,
the results obtained differ from one another. The reason is that the different
sets of diagrams have been used. Here we will argue that the quantum
corrections to metric must be independent of the choice of field variables,
i.e., must be reparametrization invariant. Using simple reparametrization
transformation, we will show that the contribution considered by BDH, is not
invariant under it. Meanwhile the contribution of the complete set of the
diagrams, considered by KK, satisfies the requirement of the invariance.
|
Cosmological inflation generates a spectrum of density perturbations that can
seed the cosmic structures we observe today. These perturbations are usually
computed as the result of the gravitationally-induced spontaneous creation of
perturbations from an initial vacuum state. In this paper, we compute the
perturbations arising from gravitationally-induced stimulated creation when
perturbations are already present in the initial state. The effect of these
initial perturbations is not diluted by inflation and survives to its end, and
beyond. We consider a generic statistical density operator $\rho$ describing an
initial mixed state that includes probabilities for nonzero numbers of scalar
perturbations to be present at early times during inflation. We analyze the
primordial bispectrum for general configurations of the three different
momentum vectors in its arguments. We find that the initial presence of quanta
can significantly enhance non-gaussianities in the so-called squeezed limit.
Our results show that an observation of non-gaussianities in the squeezed limit
can occur for single-field inflation when the state in the very early
inflationary universe is not the vacuum, but instead contains early-time
perturbations. Valuable information about the initial state can then be
obtained from observations of those non-gaussianities.
|
The operation of a source of entangled electron spins, based on a
superconductor and two quantum dots in parallel\cite{loss}, is described in
detail with the help of quantum master equations. These are derived including
the main parasitic processes in a fully consistent and non-perturbative way,
starting from a microscopic Hamiltonian. The average current is calculated,
including the contribution of entangled and non-entangled pairs. The
constraints on the operation of the device are illustrated by a calculation of
the various charge state probabilities.
|
We first review spacelike stretched warped AdS$_3$ and we describe its black
hole quotients by using accelerating and Poincar\'e coordinates. We then
describe the maximal analytic extension of the black holes and present their
causal diagrams. Finally, we calculate spacetime limits of the black hole phase
space $(T_R,T_L)$. This is done by requiring that the identification vector
$\partial_\theta$ has a finite non-zero limit. The limits we obtain are the
self-dual solution in accelerating or Poincar\'e coordinates, depending
respectively on whether the limiting spacetimes are non-extremal or extremal,
and warped AdS with a periodic proper time identification.
|
This paper is devoted to a dispersion analysis of a class of perturbed
p-Laplacians. Besides the p-Laplacian-like eigenvalue problems we also deal
with new and non-standard eigenvalue problems, which can not be solved by the
methods used in nonlinear eigenvalue problems for p-Laplacians and similar
operators. Original techniques are suggested for solving these new problems
(see Section 3). In addition, dispersion relations between the
eigen-parameters, quantitative analysis of eigenvectors and variational
principles for eigenvalues of perturbed p-Laplacians are also studied in this
paper. The problems, we study in this paper arise from the real world problems.
|
Document clustering as an unsupervised approach extensively used to navigate,
filter, summarize and manage large collection of document repositories like the
World Wide Web (WWW). Recently, focuses in this domain shifted from traditional
vector based document similarity for clustering to suffix tree based document
similarity, as it offers more semantic representation of the text present in
the document. In this paper, we compare and contrast two recently introduced
approaches to document clustering based on suffix tree data model. The first is
an Efficient Phrase based document clustering, which extracts phrases from
documents to form compact document representation and uses a similarity measure
based on common suffix tree to cluster the documents. The second approach is a
frequent word/word meaning sequence based document clustering, it similarly
extracts the common word sequence from the document and uses the common
sequence/ common word meaning sequence to perform the compact representation,
and finally, it uses document clustering approach to cluster the compact
documents. These algorithms are using agglomerative hierarchical document
clustering to perform the actual clustering step, the difference in these
approaches are mainly based on extraction of phrases, model representation as a
compact document, and the similarity measures used for clustering. This paper
investigates the computational aspect of the two algorithms, and the quality of
results they produced.
|
The main result of this paper is some "annulus" formula for the relative
extremal function in the context of Stein spaces (Theorem 1.1). Our result may
be useful in the theory of the extension of separately holomorphic functions on
generalized (N,k)-crosses lying in the product of Stein manifolds (Theorem
4.6).
|
We consider orthogonal polynomials on the surface of a double cone or a
hyperboloid of revolution, either finite or infinite in axis direction, and on
the solid domain bounded by such a surface and, when the surface is finite, by
hyperplanes at the two ends. On each domain a family of orthogonal polynomials,
related to the Gegebauer polynomials, is study and shown to share two
characteristic properties of spherical harmonics: they are eigenfunctions of a
second order linear differential operator with eigenvalues depending only on
the polynomial degree, and they satisfy an addition formula that provides a
closed form formula for the reproducing kernel of the orthogonal projection
operator. The addition formula leads to a convolution structure, which provides
a powerful tool for studying the Fourier orthogonal series on these domains.
Furthermore, another family of orthogonal polynomials, related to the Hermite
polynomials, is defined and shown to be the limit of the first family, and
their properties are derived accordingly.
|
We present magnetic susceptibility, heat capacity, and neutron diffraction
measurements of polycrystalline Nd2Ru2O7 down to 0.4 K. Three anomalies in the
magnetic susceptibility measurements at 146, 21 and 1.8 K are associated with
an antiferromagnetic ordering of the Ru4+ moments, a weak ferromagnetic signal
attributed to a canting of the Ru4+ and Nd3+ moments, and a long-range-ordering
of the Nd3+ moments, respectively. The long-range order of the Nd3+ moments was
observed in all the measurements, indicating that the ground state of the
compound is not a spin glass. The magnetic entropy of Rln2 accumulated up to 5
K, suggests the Nd3+ has a doublet ground state. Lattice distortions accompany
the transitions, as revealed by neutron diffraction measurements, and in
agreement with earlier synchrotron x-ray studies. The magnetic moment of the
Nd3+ ion at 0.4 K is estimated to be 1.54(2){\mu}B and the magnetic structure
is all-in all-out as determined by our neutron diffraction measurements.
|
Establishing dense correspondences between a pair of images is an important
and general problem. However, dense flow estimation is often inaccurate in the
case of large displacements or homogeneous regions. For most applications and
down-stream tasks, such as pose estimation, image manipulation, or 3D
reconstruction, it is crucial to know when and where to trust the estimated
matches.
In this work, we aim to estimate a dense flow field relating two images,
coupled with a robust pixel-wise confidence map indicating the reliability and
accuracy of the prediction. We develop a flexible probabilistic approach that
jointly learns the flow prediction and its uncertainty. In particular, we
parametrize the predictive distribution as a constrained mixture model,
ensuring better modelling of both accurate flow predictions and outliers.
Moreover, we develop an architecture and training strategy tailored for robust
and generalizable uncertainty prediction in the context of self-supervised
training. Our approach obtains state-of-the-art results on multiple challenging
geometric matching and optical flow datasets. We further validate the
usefulness of our probabilistic confidence estimation for the task of pose
estimation. Code and models are available at
https://github.com/PruneTruong/PDCNet.
|
In this paper, we present our participation to CLEF MC2 2018 edition for the
task 2 Mining opinion argumentation. It consists in detecting the most
argumentative and diverse Tweets about some festivals in English and French
from a massive multilingual collection. We measure argumentativity of a Tweet
computing the amount of argumentation compounds it contains. We consider
argumentation compounds as a combination between opinion expression and its
support with facts and a particular structuration. Regarding diversity, we
consider the amount of festival aspects covered by Tweets. An initial step
filters the original dataset to fit the language and topic requirements of the
task. Then, we compute and integrate linguistic descriptors to detect claims
and their respective justifications in Tweets. The final step extracts the most
diverse arguments by clustering Tweets according to their textual content and
selecting the most argumentative ones from each cluster. We conclude the paper
describing the different ways we combined the descriptors among the different
runs we submitted and discussing their results.
|
The expanding model size and computation of deep neural networks (DNNs) have
increased the demand for efficient model deployment methods. Quantization-aware
training (QAT) is a representative model compression method to leverage
redundancy in weights and activations. However, most existing QAT methods
require end-to-end training on the entire dataset, which suffers from long
training time and high energy costs. Coreset selection, aiming to improve data
efficiency utilizing the redundancy of training data, has also been widely used
for efficient training. In this work, we propose a new angle through the
coreset selection to improve the training efficiency of quantization-aware
training. Based on the characteristics of QAT, we propose two metrics: error
vector score and disagreement score, to quantify the importance of each sample
during training. Guided by these two metrics of importance, we proposed a
quantization-aware adaptive coreset selection (ACS) method to select the data
for the current training epoch. We evaluate our method on various networks
(ResNet-18, MobileNetV2), datasets(CIFAR-100, ImageNet-1K), and under different
quantization settings. Compared with previous coreset selection methods, our
method significantly improves QAT performance with different dataset fractions.
Our method can achieve an accuracy of 68.39% of 4-bit quantized ResNet-18 on
the ImageNet-1K dataset with only a 10% subset, which has an absolute gain of
4.24% compared to the baseline.
|
Let $(X,J) $ be an almost complex manifold with a (smooth) involution
$\sigma:X\to X$ such that $Fix(\sigma)\neq \emptyset$. Assume that $\sigma$ is
a complex conjugation, i.e, the differential of $\sigma$ anti-commutes with
$J$. The space $P(m,X):=\mathbb{S}^m\times X/\!\sim$ where $(v,x)\sim
(-v,\sigma(x))$ is known as a generalized Dold manifold. Suppose that a group
$G\cong \mathbb Z_2^s$ acts smoothly on $X$ such that $g\circ \sigma
=\sigma\circ g$ for all $g\in G$. Using the action of the diagonal subgroup
$D=O(1)^{m+1}\subset O(m+1)$ on the sphere $\mathbb S^{m}$ for which there are
only finitely many pairs of antipodal points that are stablized by $D$, we
obtain an action of $\mathcal G=D\times G$ on $\mathbb S^m\times X$, which
descends to a (smooth) action of $\mathcal G$ on $P(m,X)$. When the stationary
point set $X^G$ for the $G$ action on $X$ is finite, the same also holds for
the $\mathcal G$ action on $P(m,X)$. The main result of this note is that the
equivariant cobordism class $[P(m,X),\mathcal G]$ vanishes if and only if
$[X,G]$ vanishes. We illustrate this result in the case when $X$ is the complex
flag manifold, $\sigma$ is the natural complex conjugation and $G\cong (\mathbb
Z_2)^n$ is contained in the diagonal subgroup of $U(n)$.
|
We propose a new long video dataset (called Track Long and Prosper - TLP) and
benchmark for single object tracking. The dataset consists of 50 HD videos from
real world scenarios, encompassing a duration of over 400 minutes (676K
frames), making it more than 20 folds larger in average duration per sequence
and more than 8 folds larger in terms of total covered duration, as compared to
existing generic datasets for visual tracking. The proposed dataset paves a way
to suitably assess long term tracking performance and train better deep
learning architectures (avoiding/reducing augmentation, which may not reflect
real world behaviour). We benchmark the dataset on 17 state of the art trackers
and rank them according to tracking accuracy and run time speeds. We further
present thorough qualitative and quantitative evaluation highlighting the
importance of long term aspect of tracking. Our most interesting observations
are (a) existing short sequence benchmarks fail to bring out the inherent
differences in tracking algorithms which widen up while tracking on long
sequences and (b) the accuracy of trackers abruptly drops on challenging long
sequences, suggesting the potential need of research efforts in the direction
of long-term tracking.
|
We investigate the 5d transition metal oxide BaOsO$_3$ within a combination
of density functional theory (DFT) and dynamical mean-field theory (DMFT),
using a matrix-product-state impurity solver. BaOsO$_3$ has 4 electrons in the
t$_{2g}$ shell akin to ruthenates but stronger spin-orbit coupling (SOC) and is
thus expected to reveal an interplay of Hund's metal behavior with SOC. We
explore the paramagnetic phase diagram as a function of SOC and Hubbard
interaction strengths, identifying metallic, band (van-Vleck) insulating and
Mott insulating regions. At the physical values of the two couplings we find
that BaOsO$_3$ is still situated inside the metallic region and has a moderate
quasiparticle renormalization $m^*/m \approx 2$; consistent with specific heat
measurements. SOC plays an important role in suppressing electronic
correlations (found in the vanishing SOC case) through the splitting of a
van-Hove singularity (vHs) close to the Fermi energy, but is insufficient to
push the material into an insulating van-Vleck regime. In spite of the strong
effect of SOC, BaOsO$_3$ can be best pictured as a moderately correlated Hund's
metal.
|
In this paper, we introduce a new notion of biprojectivity, called
$WAP$-biprojectivity for $F(\mathcal{A})$, the enveloping dual Banach algebra
associated to a Banach algebra $\mathcal{A}$. We find some relations between
Connes biprojectivity, Connes amenability and this new notion. We show that,
for a given dual Banach algebra $\mathcal{A}$, if $F(\mathcal{A})$ is Connes
amenable, then $\mathcal{A}$ is Connes amenable.
For an infinite commutative compact group $G$, we show that the convolution
Banach algebra $F(L^2(G))$ is not $WAP$-biprojective. Finally, we provide some
examples of the enveloping dual Banach algebras and we study their
$WAP$-biprojectivity and Connes amenability.
|
In his proof of the fundamental lemma, Ng\^o established the product formula
for the Hitchin fibration over the anisotropic locus. One expects this formula
over the larger generically regular semisimple locus, and we confirm this by
deducing the relevant vanishing statement for torsors over loop groups $R((t))$
from a general formula for $\mathrm{Pic}(R((t)))$. In the build up to the
product formula, we present general algebraization, approximation, and
invariance under Henselian pairs results for torsors, give short new proofs for
the Elkik approximation theorem and the Chevalley isomorphism $\mathfrak{g}//G
\cong \mathfrak{t}/W$, and improve results on the geometry of the Chevalley
morphism $\mathfrak{g} \rightarrow \mathfrak{g}//G$.
|
We show existence of the weak large deviation principle, with a convex rate
function, for the renormalized distance from the starting point of irreducible
random walks on relatively hyperbolic groups. Under the assumption of
finiteness of exponential moments, the full large deviation principle holds,
and the rate function governing it can be expressed as the Fenchel-Legendre
transform of the limiting logarithmic moment generating function of the
sequence of renormalized distances.
|
A compact hyperbolic "cobweb" manifold (hyperbolic space form) of symbol
$Cw(6,6,6)$ will be constructed in Fig.1,4,5 as a representant of a presumably
infinite series $Cw(2p,2p,2p)$ $(3 \le p \in \bN$ natural numbers). This is a
by-product of our investigations \cite{MSz16}. In that work dense ball packings
and coverings of hyperbolic space $\HYP$ have been constructed on the base of
complete hyperbolic Coxeter orthoschemes $\mathcal{O}=W_{uvw}$ and its extended
reflection groups $\bG$ (see diagram in Fig.~3. and picture of fundamental
domain in Fig.~2). Now $u=v=w=6 (=2p)$. Thus the maximal ball contained in
$Cw(6,6,6)$, moreover its minimal covering bal l (so diameter) can also be
determined. The algorithmic procedure provides us with the proof of our
statements.
|
Detecting large-scale flux ropes (FRs) embedded in interplanetary coronal
mass ejections (ICMEs) and assessing their geoeffectiveness are essential since
they can drive severe space weather. At 1 au, these FRs have an average
duration of 1 day. Their most common magnetic features are large, smoothly
rotating magnetic fields. Their manual detection has become a relatively common
practice over decades, although visual detection can be time-consuming and
subject to observer bias. Our study proposes a pipeline that utilizes two
supervised binary-classification machine learning (ML) models trained with
solar wind magnetic properties to automatically detect large-scale FRs and
additionally determine their geoeffectiveness. The first model is used to
generate a list of auto-detected FRs. Using the properties of southward
magnetic field the second model determines the geoeffectiveness of FRs. Our
method identifies 88.6\% and 80\% large-scale ICMEs (duration $\ge 1$ day)
observed at 1 au by Wind and Sun Earth Connection Coronal and Heliospheric
Investigation (STEREO) mission, respectively. While testing with a continuous
solar wind data obtained from Wind, our pipeline detected 56 of the 64
large-scale ICMEs during 2008 - 2014 period (recall= 0.875) but many false
positives (precision= 0.56) as we do not take into account any additional solar
wind properties than the magnetic properties. We found an accuracy of 0.88 when
estimating the geoeffectiveness of the auto-detected FRs using our method.
Thus, in space weather now-casting and forecasting at L1 or any planetary
missions, our pipeline can be utilized to offer a first-order detection of
large-scale FRs and geoeffectiveness.
|
PayPal is an account-based system that allows anyone with an email address to
send and receive online payment s. This service is easy to use for customers.
Members can instantaneously send money to anyone. Recipients are informed by
email that they have received a payment. PayPal is also available to people in
38 countries. This paper starts with introduction to the company and its
services. The information about the history and the current company situation
are covered. Later some interesting and different technical issues are
discussed. The Paper ends with analysis of the company and several future
recommendations.
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Compressed Sensing (CS) significantly speeds up Magnetic Resonance Image
(MRI) processing and achieves accurate MRI reconstruction from under-sampled
k-space data. According to the current research, there are still several
problems with dynamic MRI k-space reconstruction based on CS. 1) There are
differences between the Fourier domain and the Image domain, and the
differences between MRI processing of different domains need to be considered.
2) As three-dimensional data, dynamic MRI has its spatial-temporal
characteristics, which need to calculate the difference and consistency of
surface textures while preserving structural integrity and uniqueness. 3)
Dynamic MRI reconstruction is time-consuming and computationally
resource-dependent. In this paper, we propose a novel robust low-rank dynamic
MRI reconstruction optimization model via highly under-sampled and Discrete
Fourier Transform (DFT) called the Robust Depth Linear Error Decomposition
Model (RDLEDM). Our method mainly includes linear decomposition, double Total
Variation (TV), and double Nuclear Norm (NN) regularizations. By adding linear
image domain error analysis, the noise is reduced after under-sampled and DFT
processing, and the anti-interference ability of the algorithm is enhanced.
Double TV and NN regularizations can utilize both spatial-temporal
characteristics and explore the complementary relationship between different
dimensions in dynamic MRI sequences. In addition, Due to the non-smoothness and
non-convexity of TV and NN terms, it is difficult to optimize the unified
objective model. To address this issue, we utilize a fast algorithm by solving
a primal-dual form of the original problem. Compared with five state-of-the-art
methods, extensive experiments on dynamic MRI data demonstrate the superior
performance of the proposed method in terms of both reconstruction accuracy and
time complexity.
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Core-collapse supernova explosions are driven by a central engine that
converts a small fraction of the gravitational binding energy released during
core collapse to outgoing kinetic energy. The suspected mode for this energy
conversion is the neutrino mechanism, where a fraction of the neutrinos emitted
from the newly formed protoneutron star are absorbed by and heat the matter
behind the supernova shock. Accurate neutrino-matter interaction terms are
crucial for simulating these explosions. In this proceedings for IAUS 331, SN
1987A, 30 years later, we explore several corrections to the neutrino-nucleon
scattering opacity and demonstrate the effect on the dynamics of the
core-collapse supernova central engine via two dimensional
neutrino-radiation-hydrodynamics simulations. Our results reveal that the
explosion properties are sensitive to corrections to the neutral-current
scattering cross section at the 10-20% level, but only for densities at or
above $\sim 10^{12}$ g cm$^{-3}$
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Quotations are crucial for successful explanations and persuasions in
interpersonal communications. However, finding what to quote in a conversation
is challenging for both humans and machines. This work studies automatic
quotation generation in an online conversation and explores how language
consistency affects whether a quotation fits the given context. Here, we
capture the contextual consistency of a quotation in terms of latent topics,
interactions with the dialogue history, and coherence to the query turn's
existing content. Further, an encoder-decoder neural framework is employed to
continue the context with a quotation via language generation. Experiment
results on two large-scale datasets in English and Chinese demonstrate that our
quotation generation model outperforms the state-of-the-art models. Further
analysis shows that topic, interaction, and query consistency are all helpful
to learn how to quote in online conversations.
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Deep learning-based reduced order models (DL-ROMs) have been recently
proposed to overcome common limitations shared by conventional reduced order
models (ROMs) - built, e.g., through proper orthogonal decomposition (POD) -
when applied to nonlinear time-dependent parametrized partial differential
equations (PDEs). These might be related to (i) the need to deal with
projections onto high dimensional linear approximating trial manifolds, (ii)
expensive hyper-reduction strategies, or (iii) the intrinsic difficulty to
handle physical complexity with a linear superimposition of modes. All these
aspects are avoided when employing DL-ROMs, which learn in a non-intrusive way
both the nonlinear trial manifold and the reduced dynamics, by relying on deep
(e.g., feedforward, convolutional, autoencoder) neural networks. Although
extremely efficient at testing time, when evaluating the PDE solution for any
new testing-parameter instance, DL-ROMs require an expensive training stage,
because of the extremely large number of network parameters to be estimated. In
this paper we propose a possible way to avoid an expensive training stage of
DL-ROMs, by (i) performing a prior dimensionality reduction through POD, and
(ii) relying on a multi-fidelity pretraining stage, where different physical
models can be efficiently combined. The proposed POD-DL-ROM is tested on
several (both scalar and vector, linear and nonlinear) time-dependent
parametrized PDEs (such as, e.g., linear advection-diffusion-reaction,
nonlinear diffusion-reaction, nonlinear elastodynamics, and Navier-Stokes
equations) to show the generality of this approach and its remarkable
computational savings.
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We report calculations of the electronic structure and optical properties of
doped $n$-type perovskite BaSnO3 and layered perovskites. While doped BaSnO$_3$
retains its transparency for energies below the valence to conduction band
onset, the doped layered compounds exhibit below band edge optical conductivity
due to transitions from the lowest conduction band. This gives absorption in
the visible for Ba2SnO4. Thus it is important to minimize this phase in
transparent conducting oxide (TCO) films. Ba3Sn2O7 and Ba4Sn3O10 have strong
transitions only in the red and infrared, respectively. Thus there may be
opportunities for using these as wavelength filtering TCO.
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Based on the collision rules for hard needles we derive a hydrodynamic
equation that determines the coupled translational and rotational dynamics of a
tagged thin rod in an ensemble of identical rods. Specifically, based on a
Pseudo-Liouville operator for binary collisions between rods, the Mori-Zwanzig
projection formalism is used to derive a continued fraction representation for
the correlation function of the tagged particle's density, specifying its
position and orientation. Truncation of the continued fraction gives rise to a
generalised Enskog equation, which can be compared to the phenomenological
Perrin equation for anisotropic diffusion. Only for sufficiently large density
do we observe anisotropic diffusion, as indicated by an anisotropic mean square
displacement, growing linearly with time. For lower densities, the Perrin
equation is shown to be an insufficient hydrodynamic description for hard
needles interacting via binary collisions. We compare our results to
simulations and find excellent quantitative agreement for low densities and
qualtitative agreement for higher densities.
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Open-vocabulary object detection (OVD) requires solid modeling of the
region-semantic relationship, which could be learned from massive region-text
pairs. However, such data is limited in practice due to significant annotation
costs. In this work, we propose RTGen to generate scalable open-vocabulary
region-text pairs and demonstrate its capability to boost the performance of
open-vocabulary object detection. RTGen includes both text-to-region and
region-to-text generation processes on scalable image-caption data. The
text-to-region generation is powered by image inpainting, directed by our
proposed scene-aware inpainting guider for overall layout harmony. For
region-to-text generation, we perform multiple region-level image captioning
with various prompts and select the best matching text according to CLIP
similarity. To facilitate detection training on region-text pairs, we also
introduce a localization-aware region-text contrastive loss that learns object
proposals tailored with different localization qualities. Extensive experiments
demonstrate that our RTGen can serve as a scalable, semantically rich, and
effective source for open-vocabulary object detection and continue to improve
the model performance when more data is utilized, delivering superior
performance compared to the existing state-of-the-art methods.
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We investigate the influence of spatially inhomogeneous chiral
symmetry-breaking condensates in a magnetic field background on the equation of
state for compact stellar objects. After building a hybrid star composed of
nuclear and quark matter using the Maxwell construction, we find, by solving
the Tolman-Oppenheimer-Volkoff equations for stellar equilibrium, that our
equation of state supports stars with masses around 2 $M_\odot$ for values of
the magnetic field that are in accordance with those inferred from magnetar
data. The inclusion of a weak vector interaction term in the quark part allows
one to reach 2 solar masses for relatively small central magnetic fields,
making this composition a viable possibility for describing the internal
degrees of freedom of this class of astrophysical objects.
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We have measured total absolute cross sections for the Mutual Neutralization
(MN) of O- with O+/N+. A fine resolution (of about 50 meV) in the kinetic
energy spectra of the product neutral atoms allows unique identification of the
atomic states participating in the mutual neutralization process. Cross
sections and branching ratios have also been calculated down to 1 meV
center-of-mass collision energy for these two systems with a multi-channel
Landau-Zener model and an asymptotic method for the ionic-covalent coupling
matrix elements. The importance of two-electron processes in one-electron
transfer is demonstrated by the dominant contribution of a core-excited
configuration of the nitrogen atom in N+ + O- collisions. This effect is
partially accounted for by introducing configuration mixing in the evaluation
of coupling matrix elements.
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We present microwave experiments on the symmetry reduced 5-disk billiard
studying the transition from a closed to an open system. The measured microwave
reflection signal is analyzed by means of the harmonic inversion and the
counting function of the resulting resonances is studied. For the closed system
this counting function shows the Weyl asymptotic with a leading exponent equal
to 2. By opening the system successively this exponent decreases smoothly to an
non-integer value. For the open systems the extraction of resonances by the
harmonic inversion becomes more challenging and the arising difficulties are
discussed. The results can be interpreted as a first experimental indication
for the fractal Weyl conjecture for resonances.
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We study chaotic size dependence of the low temperature correlations in the
SK spin glass. We prove that as temperature scales to zero with volume, for any
typical coupling realization, the correlations cycle through every spin
configuration in every fixed observation window. This cannot happen in
short-ranged models as there it would mean that every spin configuration is an
infinite-volume ground state. Its occurrence in the SK model means that the
commonly used `modified clustering' notion of states sheds little light on the
RSB solution of SK, and conversely, the RSB solution sheds little light on the
thermodynamic structure of EA models.
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We propose a continuous non-convex variational model for Single Molecule
Localisation Microscopy (SMLM) super-resolution in order to overcome light
diffraction barriers. Namely, we consider a variation of the Continuous Exact
$\ell_0$ (CEL0) penalty recently introduced to relax the $\ell_2-\ell_0$
problem where a weighted-$\ell_2$ data fidelity is considered to model
signal-dependent Poisson noise. For the numerical solution of the associated
minimisation problem, we consider an iterative reweighted $\ell_1$ (IRL1)
strategy for which we detail efficient parameter computation strategies. We
report qualitative and quantitative molecule localisation results showing that
the proposed weighted-CEL0 (wCEL0) model improves the results obtained by CEL0
and state-of-the art deep-learning approaches for the high-density SMLM ISBI
2013 dataset.
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Non-parametric tests can determine the better of two stochastic optimization
algorithms when benchmarking results are ordinal, like the final fitness values
of multiple trials. For many benchmarks, however, a trial can also terminate
once it reaches a pre-specified target value. When only some trials reach the
target value, two variables characterize a trial's outcome: the time it takes
to reach the target value (or not) and its final fitness value. This paper
describes a simple way to impose linear order on this two-variable trial data
set so that traditional non-parametric methods can determine the better
algorithm when neither dominates. We illustrate the method with the
Mann-Whitney U-test. A simulation demonstrates that U-scores are much more
effective than dominance when tasked with identifying the better of two
algorithms. We test U-scores by having them determine the winners of the CEC
2022 Special Session and Competition on Real-Parameter Numerical Optimization.
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Entanglement is a unique nature of quantum theory and has tremendous
potential for application. Nevertheless, the complexity of quantum entanglement
grows exponentially with an increase in the number of entangled particles. Here
we introduce a quantum state concentration scheme which decomposes the
multipartite entangled state into a set of bipartite and tripartite entangled
states. It is shown that the complexity of the entanglement induced by the
large number of particles is transformed into the high dimensions of bipartite
and tripartite entangled states for pure quantum systems. The results not only
simplify the tedious work of verifying the (in)equivalence of multipartite
entangled states, but also are instructive to the quantum many-body problem
involving multipartite entanglement.
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We show that the theorem of Ellenberg and Venkatesh on representation of
integral quadratic forms by integral positive definite quadratic forms is valid
under weaker conditions on the represented form.
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In an intensive observational campaign in the 9 month duration of Chandra
X-ray Visionary Project that was conducted in the year 2012, 39 large X-ray
flares of Sgr A* were recorded. An analysis of the times of the observed flares
reveals that the 39 flares are separated in time by intervals that are grouped
around integer numbers times 0.10333 days. This time interval is thus the
period of a uniform grid of equally spaced points on the time axis. The
grouping of the flares around tic marks of this grid is derived from the data
with at least a 3.2 {\sigma} level of statistical significance. No signal of
any period can be found among 22 flares recorded by Chandra in the years
2013-2014. If the 0.10333 d period is that of a nearly circular Keplerian orbit
around the blackhole at the center of the Galaxy, its radius is at 7.6
Schwarzschild radii. Large flares were more likely to be triggered when the
agent responsible for their outbursts was near the peri-center phase of its
slightly eccentric orbit.
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We report the discovery of an eclipsing binary - HS 0705+6700 - being an sdB
star with a faint companion. From its light curve the orbital period of 8263.87
s, the mass ratio of the system q = 0.28, the inclination of 84.4 deg and other
system parameters are derived. The companion does not contribute to the optical
light of the system except through a strong reflection effect. The
semi-amplitude of the radial velocity curve K1 = 85.8 km/s and a mass function
of f(m) = 0.00626 Msun are determined. A spectroscopic analysis of the blue
spectra results in Teff = 28800K, log g = 5.40, and log n(He)/n(H) = -2.68.
These characteristics are typical for sdB stars, as is its mass of 0.48 Msun.
According to its mass (0.13 Msun) and radius (0.19 Rsun), the companion is an M
dwarf. The primary is in a core helium burning phase of evolution, and the
system must have gone through a common envelope stage when the primary was near
the tip of the red giant branch.
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Let $\Gamma$ be an amenable countable discrete group. Fix an ergodic free
nonsingular action of $\Gamma$ on a nonatomic standard probability space. Let
$G$ be a compactly generated locally compact second countable group such that
the closure of the group of inner automorphisms of $G$ is compact in the
natural topology. It is shown that there exists a {\it bounded} ergodic
$G$-valued cocycle of $\Gamma$.
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By employing angle-resolved photoemission spectroscopy combined with
first-principles calculations, we performed a systematic investigation on the
electronic structure of LaBi, which exhibits extremely large magnetoresistance
(XMR), and is theoretically predicted to possess band anticrossing with
nontrivial topological properties. Here, the observations of the Fermi-surface
topology and band dispersions are similar to previous studies on LaSb [Phys.
Rev. Lett. 117, 127204 (2016)], a topologically trivial XMR semimetal, except
the existence of a band inversion along the $\Gamma$-$X$ direction, with one
massless and one gapped Dirac-like surface state at the $X$ and $\Gamma$
points, respectively. The odd number of massless Dirac cones suggests that LaBi
is analogous to the time-reversal $Z_2$ nontrivial topological insulator. These
findings open up a new series for exploring novel topological states and
investigating their evolution from the perspective of topological phase
transition within the family of rare-earth monopnictides.
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An important problem in contemporary physics concerns quantum-critical
fluctuations in metals. A scaling function for the momentum, frequency,
temperature and magnetic field dependence of the correlation function near a
2D-ferromagnetic quantum-critical point (QCP) is constructed, and its
singularities are determined by comparing to the recent calculations of the
correlation functions of the dissipative quantum XY model (DQXY). The
calculations are motivated by the measured properties of the metallic compound
YFe$_2$Al$_{10}$, which is a realization of the DQXY model in 2D. The
frequency, temperature and magnetic field dependence of the scaling function as
well as the singularities measured in the experiments are given by the theory
without adjustable exponents. The same model is applicable to the
superconductor-insulator transitions, classes of metallic AFM-QCPs, and as
fluctuations of the loop-current ordered state in hole-doped cuprates. The
results presented here lend credence to the solution found for the 2D-DQXY
model, and its applications in understanding quantum-critical properties of
diverse systems.
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A quantum simulator of U(1) lattice gauge theories can be implemented with
superconducting circuits. This allows the investigation of confined and
deconfined phases in quantum link models, and of valence bond solid and spin
liquid phases in quantum dimer models. Fractionalized confining strings and the
real-time dynamics of quantum phase transitions are accessible as well. Here we
show how state-of-the-art superconducting technology allows us to simulate
these phenomena in relatively small circuit lattices. By exploiting the strong
non-linear couplings between quantized excitations emerging when
superconducting qubits are coupled, we show how to engineer gauge invariant
Hamiltonians, including ring-exchange and four-body Ising interactions. We
demonstrate that, despite decoherence and disorder effects, minimal circuit
instances allow us to investigate properties such as the dynamics of electric
flux strings, signaling confinement in gauge invariant field theories. The
experimental realization of these models in larger superconducting circuits
could address open questions beyond current computational capability.
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Given the spectrum of a Hamiltonian, a methodology is developed which employs
the Landau-Ginsburg method for characterizing phase transitions in infinite
systems to identify phase transition remnants in finite fermion systems. As a
first application of our appproach we discuss pairing in finite nuclei.
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Aiming to help researchers capture output from the early stages of
engineering design projects, this article presents a new research tool for
digitally capturing physical prototypes. The motivation for this work is to
collect observations that can aid in understanding prototyping in the early
stages of engineering design projects, and this article investigates if and how
digital capture of physical prototypes can be used for this purpose.
Early-stage prototypes are usually rough and of low-fidelity and are thus often
discarded or substantially modified through the projects. Hence, retrospective
access to prototypes is a challenge when trying to gather accurate empirical
data. To capture the prototypes developed through the early stages of a
project, a new research tool has been developed for capturing prototypes
through multi-view images, along with metadata describing by whom, why, when
and where the prototypes were captured. Over the course of 17 months, this
research tool has been used to capture more than 800 physical prototypes from
76 individual users across many projects. In this article, one project is shown
in detail to demonstrate how this capturing system can gather empirical data
for enriching engineering design project cases that focus on prototyping for
concept generation. The authors also analyse the metadata provided by the
system to give understanding into prototyping patterns in the projects. Lastly,
through enabling digital capture of large quantities of data, the research tool
presents the foundations for training artificial intelligence-based predictors
and classifiers that can be used for analysis in engineering design research.
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Computers today aren't just confined to laptops and desktops. Mobile gadgets
like mobile phones and laptops also make use of it. However, one input device
that hasn't changed in the last 50 years is the QWERTY keyboard. Users of
virtual keyboards can type on any surface as if it were a keyboard thanks to
sensor technology and artificial intelligence. In this research, we use the
idea of image processing to create an application for seeing a computer
keyboard using a novel framework which can detect hand gestures with precise
accuracy while also being sustainable and financially viable. A camera is used
to capture keyboard images and finger movements which subsequently acts as a
virtual keyboard. In addition, a visible virtual mouse that accepts finger
coordinates as input is also described in this study. This system has a direct
benefit of reducing peripheral cost, reducing electronics waste generated due
to external devices and providing accessibility to people who cannot use the
traditional keyboard and mouse.
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(Draft 3) A generalized differential operator on the real line is defined by
means of a limiting process. These generalized derivatives include, as a
special case, the classical derivative and current studies of fractional
differential operators. All such operators satisfy properties such as the sum,
product/quotient rules, chain rule, etc. We study a Sturm-Liouville eigenvalue
problem with generalized derivatives and show that the general case is actually
a consequence of standard Sturm-Liouville Theory. As an application of the
developments herein we find the general solution of a generalized harmonic
oscillator. We also consider the classical problem of a planar motion under a
central force and show that the general solution of this problem is still
generically an ellipse, and that this result is true independently of the
choice of the generalized derivatives being used modulo a time shift. The
previous result on the generic nature of phase plane orbits is extended to the
classical gravitational n-body problem of Newton to show that the global nature
of these orbits is independent of the choice of the generalized derivatives
being used in defining the force law (modulo a time shift). Finally,
restricting the generalized derivatives to a special class of fractional
derivatives, we consider the question of motion under gravity with and without
resistance and arrive at a new notion of time that depends on the fractional
parameter. The results herein are meant to clarify and extend many known
results in the literature and intended to show the limitations and use of
generalized derivatives and corresponding fractional derivatives.
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Recent measurements in single-walled carbon nanotubes show that, on
resonance, all nanotubes display the same peak optical conductivity of
approximately 8 $e^2/h$, independent of radius or chirality [Joh \emph{et al.},
\emph{Nature Nanotechnology} \textbf{6}, 51 (2011)]. We show that this uniform
peak conductivity is a consequence of the relativistic band structure and
strength of the Coulomb interaction in carbon nanotubes. We further construct a
minimalist model of exciton dynamics that describes the general phenomenology
and provides an accurate prediction of the numerical value of the peak optical
conductivity. The work illustrates the need for careful treatment of relaxation
mechanisms in modeling the optoelectronic properties of carbon nanotubes.
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