物理学学术速递[1.10]
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physics物理学，共计49篇
【1】 Correlation energy of the uniform gas determined by ground state conditional probability density functional theory
标题：用基态条件概率密度泛函理论确定均匀气体的关联能
链接：https://arxiv.org/abs/2201.02599
摘要：Conditional-probability density functional theory (CP-DFT) is a formally
exact method for finding correlation energies from Kohn-Sham DFT without
evaluating an explicit energy functional. We present details on how to generate
accurate exchange-correlation energies for the ground-state uniform gas. We
also use the exchange hole in a CP antiparallel spin calculation to extract the
high-density limit. We give a highly accurate analytic solution to the
Thomas-Fermi model for this problem, showing its performance relative to
Kohn-Sham and may be useful at high temperatures. We explore several
approximations to the CP potential. Results are compared to accurate
parameterizations for both exchange-correlation energies and holes.
【2】 Explainable deep learning for insights in El Nino and river flows
标题：可解释的深度学习，以洞察厄尔尼诺现象和河流流动
链接：https://arxiv.org/abs/2201.02596
摘要：The El Nino Southern Oscillation (ENSO) is a semi-periodic fluctuation in sea
surface temperature (SST) over the tropical central and eastern Pacific Ocean
that influences interannual variability in regional hydrology across the world
through long-range dependence or teleconnections. Recent research has
demonstrated the value of Deep Learning (DL) methods for improving ENSO
prediction as well as Complex Networks (CN) for understanding teleconnections.
However, gaps in predictive understanding of ENSO-driven river flows include
the black box nature of DL, the use of simple ENSO indices to describe a
complex phenomenon and translating DL-based ENSO predictions to river flow
predictions. Here we show that eXplainable DL (XDL) methods, based on saliency
maps, can extract interpretable predictive information contained in global SST
and discover novel SST information regions and dependence structures relevant
for river flows which, in tandem with climate network constructions, enable
improved predictive understanding. Our results reveal additional information
content in global SST beyond ENSO indices, develop new understanding of how
SSTs influence river flows, and generate improved river flow predictions with
uncertainties. Observations, reanalysis data, and earth system model
simulations are used to demonstrate the value of the XDL-CN based methods for
future interannual and decadal scale climate projections.
【3】 Fieldable Muon Momentum Measurement using Coupled Pressurized Gaseous Cherenkov Detectors
标题：用耦合加压气态切伦科夫探测器测量可场µ子动量
链接：https://arxiv.org/abs/2201.02591
备注：Transactions of American Nuclear Society Winter meeting, 125 (1), 400-403, 2021
摘要：Cosmic ray muons present a large part of the radiation background and
depending on the application of interest muons can be seen as background noise,
e.g., radiation mapping, radiation protection, dosimetry, or as a useful
interrogation probe such as cosmic ray muon tomography. It is worth noting
recent developments on muon scattering tomography which has emerged as a
prospective noninvasive monitoring method for many applications including spent
nuclear fuel cask monitoring and geotomography. However, it is still very
challenging to measure muon momentum in the field, despite the apparent
benefits, without resorting to large and expensive calorimeters, ring imagers,
or time of flight detectors. Recent efforts at CNL and INFN have developed
large prototypes based on multiple Coulomb scattering coupled with the muon
momentum reconstruction algorithms. While these efforts show promise, no
portable detectors exist that can measure muon momentum in the field. In this
work, we present a new concept for measuring muon momentum using coupled
pressurized gaseous Cherenkov radiators. By carefully selecting the gas
pressure at each radiator we can optimize the muon momentum threshold for which
a muon signal will be detected. This way, a muon passing through the radiators
will only trigger those radiators with momentum threshold less than the actual
muon momentum. By measuring the presence of Cherenkov signals in each radiator,
our system can then estimate the muon momentum. The primary benefit of such a
concept is that it can be compact and portable enough so that it can be
deployed in the field separately or in combination with existing tomography
systems.
【4】 Fractional calculus modeling of cell viscoelasticity quantifies drug response and maturation more robustly than integer order models
标题：细胞粘弹性的分数微积分模型比整数阶模型更可靠地量化药物反应和成熟度
链接：https://arxiv.org/abs/2201.02589
备注：20 pages, 6 figures
摘要：It has recently been discovered that the viscoelastic properties of cells are
inherent markers reflecting the complex biological states, functions and
malfunctions of the cells. Although the extraction of model parameters from the
viscoelasticity data of many cell types has been done successfully using
integer order mechanical and power-law viscoelastic models, there are some cell
types and conditions where the goodness of fits falls behind. Thus, fractional
order viscoelastic models have been proposed as more general and better suited
for such modeling. In this work, we test such proposed generality using
published data already fitted by integer order models. We find that cell
viscoelasticity data can be fitted using fractional order viscoelastic models
in more situations than integer order. For macrophages, which are among the
white blood cells that function in the immune system, the fractional order
Kelvin-Voigt model best captures pharmacological interventions and maturation
of the cells. The steady state viscosity of macrophages decreases following
depolymerization of F-actin using the drug cytochalasin D, and also decreases
following myosin II breakdown using Blebbistatin. When macrophages are treated
with a bacterium-derived chemoattractant, the steady state viscosity decreases.
Interestingly, both the steady state viscosity and elastic modulus are
progressively altered as the cells become mature and approach senescence. Taken
together, these results show that fractional viscoelastic modeling, more
robustly than integer order modeling, enables the further quantification of
cell function and malfunction, with potential diagnostic and therapeutic
applications especially in cases of cancer and immune system dysfunctions.
【5】 Study of two-electron one-photon transition produced in collision of Ne6+ ions with Al target at low energies
标题：低能Ne~(6+)离子与Al靶碰撞产生的两电子单光子跃迁研究
链接：https://arxiv.org/abs/2201.02566
摘要：Two-electron one-photon transitions have been successfully observed for the
Ne projectile and Al target at low energy regime. Experimental energy values of
two-electron one-photon transitions are compared with previously reported
theoretical and experimental values. Ionization cross-section of two-electron
one-photon transition is reported.
【6】 Effects of vaccination efficacy on wealth distributionin kinetic epidemic models
标题：动态流行病模型中疫苗接种效果对财富分配的影响
链接：https://arxiv.org/abs/2201.02553
备注：22 pages, 20 figures
摘要：The spreading of Covid-19 pandemic has highlighted the close link between
economics and health in the context of emergency management. A widespread
vaccination campaign is considered the main tool to contain the economic
consequences. This paper will focus, at the level of wealth distribution
modelling, on the economic improvements induced by the vaccination campaign in
terms of its effectiveness rate. The economic trend during the pandemic is
evaluated resorting to a mathematical model joining a classical compartmental
model including vaccinated individuals with a kinetic model of wealth
distribution based on binary wealth exchanges. The interplay between wealth
exchanges and the progress of the infectious disease is realized by assuming on
the one hand that individuals in different compartments act differently in the
economic process and on the other hand that the epidemic affects risk in
economic transactions. Using the mathematical tools of kinetic theory, it is
possible to identify the equilibrium states of the system and the formation of
inequalities due to the pandemic in the wealth distribution of the population.
Numerical experiments highlight the importance of the vaccination campaign and
its positive effects in reducing economic inequalities in the multi-agent
society.
【7】 Optical Frequency Combs in Aqueous and Air Environments at Visible to Near-IR Wavelengths
标题：水和空气环境中可见光到近红外波段的光频梳
链接：https://arxiv.org/abs/2201.02536
摘要：The ability to detect and identify molecules at high sensitivity without the
use of labels or capture agents is important for medical diagnostics, threat
identification, environmental monitoring, and basic science. Microtoroid
optical resonators, when combined with noise reduction techniques, have been
shown capable of label-free single molecule detection, however, they still
require a capture agent and prior knowledge of the target molecule. Optical
frequency combs can potentially provide high precision spectroscopic
information on molecules within the evanescent field of the microresonator;
however, this has not yet been demonstrated in air or aqueous biological
sensing. For aqueous solutions in particular, impediments include coupling and
thermal instabilities, reduced Q factor, and changes to the mode spectrum. Here
we overcome a key challenge toward single-molecule spectroscopy using optical
microresonators: the generation of a frequency comb at visible to near-IR
wavelengths when immersed in either air or aqueous solution. The required
dispersion is achieved via intermodal coupling, which we show is attainable
using larger microtoroids, but with the same shape and material that has
previously been shown ideal for ultra-high sensitivity biosensing. We believe
that the continuous evolution of this platform will allow us in the future to
simultaneously detect and identify single molecules in both gas and liquid at
any wavelength without the use of labels.
【8】 Unexpected Coincidences in Scintillation Detector Measurements on Cosmic Rays
标题：宇宙线闪烁探测器测量中的意外巧合
链接：https://arxiv.org/abs/2201.02509
备注：12 pages, 22 figures, 6 tables
摘要：Using two scintillation detectors at various positions, we have made
measurements on signals of very low amplitude originating from cosmic rays. We
have used a slightly modified signal analyzer from the MuonLab project,
designed for measurements on the lifetime and the velocity of muons from cosmic
radiation by high school students. In our experiment we focused on the
possibilities of the apparatus to measure the time difference 'deltatime DT'
between signals in two scintillation detectors and on the signal amplitude
'pulse height PH' of the signal in one of the detectors. Time differences
between the signals at the two analyzer inputs are measured with a resolution
of 0.5 ns, the measurement of the pulse height has a resolution of about 8 mV.
We observe that as well in the vertical as in the horizontal arrangement of the
detectors deltatime measurements show unexpected coincidences between signals
at very low amplitudes in both detectors. Under usual circumstances these
effects are not observed because the amplification in the PMT and the value of
the threshold voltage are intentionally chosen in a way to avoid noise and high
count rates. The rate at which the coincidences occur is very small, less than
1 pro mille of the count rate of the individual detectors. Measurement of the
deltatime spectrum, however, turns out to be a sensitive way to detect the
presence of some rare and unexpected coincidences. It is estimated that the low
amplitude signals that are involved in the coincidences have to correspond to
energy absorptions in the order of 100 keV in the scintillator material.
【9】 Simulating a Catalyst induced Quantum Dynamical Phase Transition of a Heyrovsky reaction with different models for the environment
标题：用不同环境模型模拟催化剂诱导的Heyrovsky反应的量子动力学相变
链接：https://arxiv.org/abs/2201.02471
摘要：Through an appropriate election of the molecular orbital basis, we show
analytically that the molecular dissociation occurring in a Heyrovsky reaction
can be interpreted as a Quantum Dynamical Phase Transition, i.e., an analytical
discontinuity in the molecular energy spectrum induced by the catalyst. The
metallic substrate plays the role of an environment that produces an energy
uncertainty on the adatom. This broadening induces a critical behavior not
possible in a quantum closed system. We use suitable approximations on
symmetry, together with both Lanczos and canonical transformations, to give
analytical estimates for the critical parameters of molecular dissociation.
This occurs when the bonding to the surface is (\sqrt{2}) times the molecular
bonding. This value is slightly weakened for less symmetric situations. However
simple, this conclusion involves a high order perturbative solution of the
molecule-catalyst system. This model is further simplified to discuss how an
environment-induced critical phenomenon can be evaluated through an idealized
perturbative tunneling microscopy set-up. In this case, the energy
uncertainties in one or both atoms are either Lorentzian or Gaussian. The
former results from the Fermi Golden Rule, i.e., a Markovian approximation. The
Gaussian uncertainty, associated with non-Markovian decoherent processes,
requires the introduction of a particular model of a spin bath. The partially
coherent tunneling current is obtained from the Generalized Landauer-B\"uttiker
Equations. The resonances observed in these transport parameters reflect, in
many cases, the critical properties of the resonances in the molecular
spectrum.
【10】 Reply to the Comment on "Thermal, quantum antibunching and lasing thresholds from single emitters to macroscopic devices"
链接：https://arxiv.org/abs/2201.02468
备注：1 Figure
摘要：We deconstruct and address a comment to Carroll et al. [Phys Rev Lett 126,
063902 (2021)] (PRL) that has been posted on arXiv appearing as two versions
[arXiv:2106.15242v1] and [arXiv:2106.15242v2]. This comment claimed that a term
in the model presented in the PRL had been incorrectly omitted and that, hence,
the laser threshold predicted by the model in the PRL is unattainable. We show
that the term in question was correctly neglected because it represents
collective effects that are not observable in the devices modelled in the PRL.
Moreover, even if this term were to be included, the laser threshold would
still be present, contrary to what was claimed in the comment. We conclude that
the model presented in PRL is correct and that its results are innovative and
of wide application in laser physics and quantum optics.
【11】 Commissioning of a hybrid readout TPC test set-up and gas gain simulations
标题：混合读出TPC测试装置的调试和气体增益模拟
链接：https://arxiv.org/abs/2201.02464
备注：Proceedings of TIPP 2021, submitted to: Journal of Physics: Conference Series
摘要：A hybrid readout Time Projection Chamber (TPC) has a simultaneous optical-
and charge readout. The optical readout provides 2D images of particle tracks
in the active volume, whilst the charge readout provides additional information
on the particle position perpendicular to the image plane. A hybrid readout TPC
working at high pressure is an attractive device for physics cases where an
excellent space point resolution and a high target density is required as e.g.
measuring a neutrino beam at the source of a long baseline neutrino oscillation
experiment. In this paper we present two different lines of work towards the
goal of developing hybrid TPC technology: a) Commissioning of a set-up with gas
electron multipliers employing optical and charge readout. b) An analytical
parametrisation of the gas gain for a multi wire proportional chamber based on
garfield++ simulations, which - when validated with measurements - allows to
skip these simulations in the future altogether.
【12】 Migration studies with a Compositional Data approach: a case study of population structure in the Capital Region of Denmark
标题：成分数据方法在移民研究中的应用--以丹麦首都地区人口结构为例
链接：https://arxiv.org/abs/2201.02451
摘要：Data normalization for removing the influence of population density in
Population Geography is a common procedure that may come with an unperceived
risk. In this regard, data are constrained to a constant sum and they are
therefore not independent observations, a fundamental requirement for applying
standard multivariate statistical tools. Compositional Data (CoDa) techniques
were developed to solve the issues that the standard statistical tools have
with close data (i.e., spurious correlations, predictions outside the range,
and sub-compositional incoherence) but they are still not commonly used in the
field. Hence, we present in this article a case study where we analyse at
parish level the spatial distribution of Danes, Western migrants and
non-Western migrants in the Capital region of Denmark. By applying CoDa
techniques, we have been able to identify the spatial population segregation in
the area and we have recognized some patterns that can be used for interpreting
housing prices variations. Our exercise is a basic example of the potential of
CoDa techniques, which generate more robust and reliable results than standard
statistical procedures, but it can be generalized to other population datasets
with more complex structures.
【13】 Bayesian tomography with prior-knowledge-based parametrization and surrogate modeling
标题：基于先验知识参数化和代理建模的贝叶斯层析成像
链接：https://arxiv.org/abs/2201.02444
备注：27 pages, 14 images
摘要：We present a Bayesian tomography framework operating with
prior-knowledge-based parametrization that is accelerated by surrogate models.
Standard high-fidelity forward solvers solve wave equations with natural
spatial parametrizations based on fine discretization. Similar
parametrizations, typically involving tens of thousand of variables, are
usually employed to parameterize the subsurface in tomography applications.
When the data do not allow to resolve details at such finely parameterized
scales, it is often beneficial to instead rely on a prior-knowledge-based
parametrization defined on a lower dimension domain (or manifold). Due to the
increased identifiability in the reduced domain, the concomitant inversion is
better constrained and generally faster. We illustrate the potential of a
prior-knowledge-based approach by considering ground penetrating radar (GPR)
travel-time tomography in a crosshole configuration. An effective
parametrization of the input (i.e., the permittivity distributions) and
compression in the output (i.e., the travel-time gathers) spaces are achieved
via data-driven principal component decomposition based on random realizations
of the prior Gaussian-process model with a truncation determined by the
performances of the standard solver on the full and reduced model domains. To
accelerate the inversion process, we employ a high-fidelity polynomial chaos
expansion (PCE) surrogate model. We show that a few hundreds design data sets
is sufficient to provide reliable Markov chain Monte Carlo inversion.
Appropriate uncertainty quantification is achieved by reintroducing the
truncated higher-order principle components in the original model space after
inversion on the manifold and by adapting a likelihood function that accounts
for the fact that the truncated higher-order components are not completely
located in the null-space.
【14】 Entrainment, diffusion and effective compressibility in a self-similar turbulent jet
标题：自相似湍流射流中的卷吸、扩散和有效压缩率
链接：https://arxiv.org/abs/2201.02443
备注：Submitted to Journal of Fluid Mechanics
摘要：An experimental Lagrangian study based on particle tracking velocimetry has
been completed in an incompressible turbulent round water jet freely spreading
into water. The jet is seeded with tracers only through the nozzle:
inhomogeneous seeding called nozzle seeding. The Lagrangian flow tagged by
these tracers therefore does not contain any contribution from particles
entrained into the jet from the quiescent surrounding fluid. The mean velocity
field of the nozzle seeded flow, $\langle \boldsymbol{U_\varphi} \rangle$, is
found to be essentially indistinguishable from the global mean velocity field
of the jet, $\langle \boldsymbol{U} \rangle$, for the axial velocity while
significant deviations are found for the radial velocity. This results in an
effective compressibility of the nozzle seeded flow for which
$\boldsymbol{\nabla \cdot} \langle \boldsymbol{U_\varphi} \rangle \neq 0$ even
though the global background flow is fully incompressible. By using mass
conservation and self-similarity, we quantitatively explain the modified radial
velocity profile and analytically express the missing contribution associated
to entrained fluid particles. By considering a classical advection-diffusion
description, we explicitly connect turbulent diffusion of mass (through the
turbulent diffusivity $K_T$) and momentum (through the turbulent viscosity
$\nu_T$) to entrainment. This results in new practical relations to
experimentally determine the non-uniform spatial profiles of $K_T$ and $\nu_T$
(and hence of the turbulent Prandtl number $\sigma_T = \nu_T/K_T$) from simple
measurements of the mean tracer concentration and axial velocity profiles.
Overall, the proposed approach based on nozzle seeded flow gives new
experimental and theoretical elements for a better comprehension of turbulent
diffusion and entrainment in turbulent jets.
【15】 A new Lagrangian drift mechanism due to current-bathymetry interactions: applications in coastal cross-shelf transport
标题：由海流-测深相互作用引起的一种新的拉格朗日漂移机制：在海岸跨陆架运输中的应用
链接：https://arxiv.org/abs/2201.02422
摘要：We show that in free surface flows, a uniform, streamwise current over
small-amplitude rippled bottom topography generates cross-stream drift
velocity. This Lagrangian drift, referred to as the current-bathymetry
interaction induced drift (CBIID), is specifically understood in the context of
a simplified nearshore environment, consisting of uniform alongshore current,
onshore propagating surface waves, and monochromatic rippled bathymetry making
an oblique angle with the shoreline. CBIID is found to originate from the
steady, non-homogeneous solution of the governing system of equations. Similar
to Stokes drift induced by surface waves, CBIID can also have important
implications in cross-shelf tracer transport. CBIID increases with particle's
depth, bottom ripple's wavelength and amplitude, and the magnitude of the
alongshore current. Moreover, maximum cross-shelf transport by CBIID is
obtained when the bottom ripple wave-vector approximately makes $\pi/4$ angle
with the shoreline. Depending on the angle between the alongshore current and
the bottom ripple wave-vector, CBIID can lead to onshoreward or offshoreward
tracer transport. Unlike Stokes drift, particle excursions due to
current-bathymetry interactions might not be small, hence analytical
expressions based on small-excursion approximation could be inaccurate. We
provide an alternative $z$-bounded approximation, which provides highly
accurate expressions of drift velocity and time period for particles near the
free surface. Realistic parametric analysis reveals that in situations where
the Stokes drift and CBIID velocities have comparable magnitudes, they are
order separated both in length and time scales. We infer that high-resolution
coastal bathymetry maps are crucial for accurate predictions of tracer
transport pathways in the nearshore environment.
【16】 Laser-Driven, Ion-Scale Magnetospheres in Laboratory Plasmas. II. Particle-in-cell Simulations
标题：实验室等离子体中激光驱动的离子尺度磁层。II.细胞内粒子模拟
链接：https://arxiv.org/abs/2201.02416
摘要：Ion-scale magnetospheres have been observed around comets, weakly-magnetized
asteroids, and localized regions on the Moon, and provide a unique environment
to study kinetic-scale plasma physics, in particular in the collisionless
regime. In this work, we present the results of particle-in-cell simulations
that replicate recent experiments on the Large Plasma Device at the University
of California, Los Angeles. Using high-repetition rate lasers, ion-scale
magnetospheres were created to drive a plasma flow into a dipolar magnetic
field embedded in a uniform background magnetic field. The simulations are
employed to evolve idealized 2D configurations of the experiments, study
highly-resolved, volumetric datasets and determine the magnetospheric
structure, magnetopause location and kinetic-scale structures of the plasma
current distribution. We show the formation of a magnetic cavity and a magnetic
compression in the magnetospheric region, and two main current structures in
the dayside of the magnetic obstacle: the diamagnetic current, supported by the
driver plasma flow, and the current associated to the magnetopause, supported
by both the background and driver plasmas with some time-dependence. From
multiple parameter scans, we show a reflection of the magnetic compression,
bounded by the length of the driver plasma, and a higher separation of the main
current structures for lower dipolar magnetic moments.
【17】 Camel back shaped Kirkwood-Buff Integrals
标题：驼背形Kirkwood-Buff积分
链接：https://arxiv.org/abs/2201.02406
摘要：Some binary mixtures, such as specific alcohol-alkane mixtures, or even
water-tbutanol, exhibit two humps camel back shaped KBI. This is in sharp
contrast with usual KBI of binary mixtures having a single extremum. This
extremum is interpreted as the region of maximum concentration fluctuations,
and usually occurs in binary mixtures presenting appreciable micro-segregation,
and corresponds to where the mixture exhibit a percolation of the two species
domains. In this paper, it is shown that two extrema occur in binary mixtures
when one species forms "meta-particle" aggregates, the latter which act as a
meta-species, and have their own concentration fluctuations, hence their own
KBI extremum. This "meta-extremum" occurs at low concentration of the
aggregate-forming species (such as alcohol in alkane), and is independant of
the other usual extremum observed at mid volume fraction occupancy. These
systems are a good illustration of the concept of the duality between
concentration fluctuations and micro-segregation.
【18】 Hyperparameter Search using Genetic Algorithm for Surrogate Modeling of Geophysical Flows
标题：基于遗传算法的地球物理流代理建模超参数搜索
链接：https://arxiv.org/abs/2201.02389
摘要：The computational models for geophysical flows are computationally very
expensive to employ in multi-query tasks such as data assimilation, uncertainty
quantification, and hence surrogate models sought to alleviate the
computational burden associated with these full order models. Researchers have
started applying machine learning algorithms, particularly neural networks, to
build data-driven surrogate models for geophysical flows. The performance of
the neural network highly relies upon its architecture design and selection of
other hyperparameters. These neural networks are usually manually designed
through trial and error to maximize their performance. This often requires
domain knowledge of the neural network as well as the problems of interest.
This limitation can be addressed by using an evolutionary algorithm to
automatically design architecture and select optimal hyperparameters of the
neural network. In this paper, we apply the genetic algorithm to effectively
design the long short-term memory (LSTM) neural network to build the
non-intrusive reduced order model of the sea-surface temperature field.
【19】 Systematic treatment of hypernuclear data and application to the hypertriton
标题：超核数据的系统处理及其在超中子中的应用
链接：https://arxiv.org/abs/2201.02368
备注：6 pages, 3 figures, HADRON 2021 Proceeding
摘要：A database is under construction to provide a complete collection of
published basic properties of hypernuclei such as {\Lambda} binding energies,
lifetimes, or excitation energies. From these values, averages with related
errors are computed in a systematic way. For each property, the overall
experimental situation is depicted in form of an ideogram showing the combined
probability density function of the measurements. The database is accessible
via a dynamic website at https://hypernuclei.kph.uni-mainz.de with an user
interface offering customizable visualizations, selections, or unit
conversions. The capabilities of the database are demonstrated for the puzzling
and disputed data situation of the hypertriton.
【20】 Highly coordinated nationwide massive travel restrictions are central to effective mitigation and control of COVID-19 outbreaks in China
标题：全国范围内高度协调的大规模旅行限制是有效缓解和控制中国冠状病毒爆发的核心
链接：https://arxiv.org/abs/2201.02353
备注：22 pages, 5 figures
摘要：The COVID-19, the disease caused by the novel coronavirus 2019 (SARS-CoV-2),
has caused graving woes across the globe since first reported in the epicenter
Wuhan, Hubei, China, December 2019. The spread of COVID-19 in China has been
successfully curtailed by massive travel restrictions that put more than 900
million people housebound for more than two months since the lockdown of Wuhan
on 23 January 2020 when other provinces in China followed suit. Here, we assess
the impact of China's massive lockdowns and travel restrictions reflected by
the changes in mobility patterns before and during the lockdown period. We
quantify the synchrony of mobility patterns across provinces and within
provinces. Using these mobility data, we calibrate movement flow between
provinces in combination with an epidemiological compartment model to quantify
the effectiveness of lockdowns and reductions in disease transmission. Our
analysis demonstrates that the onset and phase of local community transmission
in other provinces depends on the cumulative population outflow received from
the epicenter Hubei. As such, infections can propagate further into other
interconnected places both near and far, thereby necessitating synchronous
lockdowns. Moreover, our data-driven modeling analysis shows that lockdowns and
consequently reduced mobility lag a certain time to elicit an actual impact on
slowing down the spreading and ultimately putting the epidemic under check. In
spite of the vastly heterogeneous demographics and epidemiological
characteristics across China, mobility data shows that massive travel
restrictions have been applied consistently via a top-down approach along with
high levels of compliance from the bottom up.
【21】 Can bus bunching reduce waiting time?
标题：公交车挤在一起能缩短候车时间吗？
链接：https://arxiv.org/abs/2201.02343
摘要：Bus bunching is ostensibly regarded as a detrimental phenomenon in bus
systems. We study a bus loop with two bus stops, one regular and one spike bus
stop, where bunched buses can outperform staggered buses. The spike bus stop
models a bus stop connected to a train or metro service, where passengers
arrive in groups at periodic intervals (spikes). We introduce the configuration
of synchronised bunched buses, where bunched buses wait for the spike in
demand. For a wide range of parameters, synchronised bunched buses outperform
perfectly staggered buses in terms of minimising the waiting time of commuters.
We present an analytical formulation of the average waiting time in the case of
bunched buses, synchronised bunched buses and perfectly staggered buses with
the consideration of different passenger demand, number of buses, and bus
capacity. We demonstrate the validity of our analytical results through an
agent-based simulation of the bus loop system.
【22】 Towards an accelerated decarbonization of chemical industry by electrolysis
标题：用电解法加速化学工业脱碳
链接：https://arxiv.org/abs/2201.02335
摘要：The transition towards carbon-neutral chemicals production is challenging due
to the fundamental reliance of the chemical sector on petrochemical feedstocks
inputs. Electrolysis-based manufacturing, powered by renewables, is a rapidly
evolving technology that might be capable of a drastic reduction of CO2
emissions from the chemical sector. However, will it be possible to scale-up
electrolysis systems to an extent necessary to entirely decarbonize all
chemical plants? Applying a forward looking scenario, this perspective
estimates how much energy will be needed to power full-scale electrolysis based
chemical manufacturing by 2050. A significant gap is identified between the
currently planned renewable energy expansion, and the energy input necessary to
electrify the chemical production. To cover this gap, several strategies
enabling a meaningful reduction of energy input to electrolysis are being
discussed from the perspective of both a single electrolysis system and an
integrated electro-plant. Several scale-up oriented research priorities are
formulated to underpin timely development and commercial availability of
described technologies, as well as to explore synergies and support further
growth of the renewable energy sector, essential to realize described paradigm
shift in chemical manufacturing.
【23】 Mitigation of thermoacoustic instability in a turbulent combustor via self-coupling
标题：湍流燃烧室中热声不稳定性的自耦合缓解
链接：https://arxiv.org/abs/2201.02328
备注：17 pages, 6 figures, Preprint under review in Proceedings of The Combustion Institute
摘要：In this paper, we report the first observation of complete mitigation of
thermoacoustic instability in a bluff-body stabilized turbulent combustor
through the method of self-coupling. Self-coupling is achieved by coupling the
acoustic field of the combustor to itself through a coupling tube. We
characterize the effects of such acoustic self-feedback on the thermoacoustic
instability of the system by varying the length and diameter of the coupling
tube. We observe that the amplitude and the dominant frequency of the acoustic
pressure fluctuations gradually decrease as the length of the coupling tube is
increased. A complete suppression of thermoacoustic instability is observed
when the coupling tube length is nearly 1.5 times the combustor length.
Meanwhile, as we approach the suppression of thermoacoustic instability, the
dynamical behavior of acoustic pressure changes from the state of limit cycle
oscillations to low amplitude aperiodic oscillations via intermittency. We also
study the coupling between the acoustic field and the unsteady flame dynamics
for different conditions of self-coupling in the combustor. As the combustor
approaches the state of complete suppression, the temporal synchrony between
the acoustic pressure and the global heat release rate signals changes from the
state of synchronized periodicity to desynchronized aperiodicity through
intermittent synchronization. From the spatiotemporal analysis of the combustor
flow field, we find complete disruption of the coherent spatial structures of
acoustic energy production observed during the state of thermoacoustic
instability when the combustor is self-coupled with a tube of optimized size.
Thus, we anticipate self-coupling to be a viable option to mitigate high
amplitude thermoacoustic oscillations in turbulent combustion systems present
in gas turbines and rocket engines.
【24】 Reconstructing Rayleigh-Bénard flows out of temperature-only measurements using nudging
标题：用Nudging方法重建纯温度测量的Rayleigh-Bénard流
链接：https://arxiv.org/abs/2201.02306
摘要：Nudging is a data assimilation technique that has proved to be capable of
reconstructing several highly turbulent flows from a set of partial
spatiotemporal measurements. In this study we apply the nudging protocol on the
temperature field in a Rayleigh-B\'enard Convection system at varying levels of
turbulence. We assess the global, as well as scale by scale, success in
reconstructing the flow and the transition to full synchronization while
varying both the quantity and quality of the information provided by the sparse
measurements either on the Eulerian or Lagrangian domain. We asses the
statistical reproduction of the dynamic behaviour of the system by studying the
spectra of the nudged fields as well as the correct prediction of the heat
transfer properties as measured by the Nusselt number. Further, we analyze the
results in terms of the complexity of the solutions at various Rayleigh numbers
and discuss the more general problem of predicting all state variables of a
system given partial or full measurements of only one subset of the fields, in
particular temperature. This study sheds new light on the correlation between
velocity and temperature in thermally driven flows and on the possibility to
control them by acting on the temperature only.
【25】 Epidemics on evolving networks with varying degrees
标题：不同程度进化网络上的流行病
链接：https://arxiv.org/abs/2201.02299
摘要：Epidemics on complex networks is a widely investigated topic in the last few
years, mainly due to the last pandemic events. Usually, real contact networks
are dynamic, hence much effort has been invested in studying epidemics on
evolving networks. Here we propose and study a model for evolving networks
based on varying degrees, where at each time step a node might get, with
probability $r$, a new degree and new neighbors according to a given degree
distribution, instead of its former neighbors. We find analytically, using the
generating functions framework, the epidemic threshold and the probability for
a macroscopic spread of disease depending on the rewiring rate $r$. Our
analytical results are supported by numerical simulations. We find surprisingly
that the impact of the rewiring rate $r$ has qualitative different trends for
networks having different degree distributions. That is, in some structures,
such as random regular networks the dynamics enhances the epidemic spreading
while in others such as scale free the dynamics reduces the spreading. In
addition, for scale-free networks, we reveal that fast dynamics of the network,
$r=1$, changes the epidemic threshold to nonzero rather than zero found for
$r<1$, which is similar to the known case of $r=0$, \textit{i.e.}, a static
network. Finally, we find the epidemic threshold also for a general
distribution of the recovery time.
【26】 Verification of Operational Numerical Weather Prediction Model Forecasts of Precipitation Using Satellite Rainfall Estimates over Africa
标题：使用非洲上空卫星降雨量估计的降水预报业务数值天气预报模式的验证
链接：https://arxiv.org/abs/2201.02296
备注：50 pages, 10 figures, 3 supplementary figures
摘要：Rainfall is an important variable to be able to monitor and forecast across
Africa, due to its impact on agriculture, food security, climate related
diseases and public health. Numerical Weather Models (NWM) are an important
component of this work, due to their complete spatial coverage, high
resolution, and ability to forecast into the future. In this study, we seek to
evaluate the spatiotemporal skill of short-term rainfall forecasts of rainfall
across Africa. Specifically, the European Centre for Medium-Range Weather
Forecasts (ECMWF) and the National Centers for Environmental Prediction-Global
Forecast System (NCEP-GFS) forecast models are verified by Rainfall Estimates
2.0 (RFE2) and African Rainfall Climatology Version 2 (ARC2), which are fused
products of satellite and in-situ observations and are commonly used in
analysis of African rainfall. We found that the model rainfall forecasts show
good consistency with the satellite rainfall observations in spatial
distribution over Africa on the seasonal timescale. Evaluation metrics show
high spatial and seasonal variations over the African continent, including a
strong link to the location of the inter-tropical convergence zone (ITCZ) and
topographically enhanced precipitation. The rainfall forecasts at one week
aggregation time are improved against daily forecasts.
【27】 FLASH Depletion of Oxygen in Tumor and Normal Tissue, and its Likely Consequences
标题：肿瘤和正常组织中的快速耗氧性及其可能的后果
链接：https://arxiv.org/abs/2201.02278
摘要：Ultra-high dose rate (FLASH) radiation has been reported to efficiently
suppress tumor growth while sparing normal tissue, however, the mechanism of
the differential tissue sparing effect is still not known. Oxygen has long been
known to profoundly impact radiobiological responses, and radiolytic oxygen
depletion has been considered to be a possible cause or contributor to the
FLASH phenomenon. This work investigates the impact of tissue pO2 profiles,
oxygen depletion per unit dose, and the oxygen concentration yielding
half-maximal radiosensitization in tumor and normal tissue. Previously reported
ranges and uncertainties in the aforementioned parameters were used to
calculate the response of normal breast and breast tumor based on the linear
quadratic-linear (LQ-L) model. The results suggest that the therapeutic
efficacy of FLASH oxygen depletion is likely patient dependent and beneficial
in a minority of cases. Circumstances under which FLASH oxygen depletion could
be of therapeutic benefit or deficit were identified.
【28】 Photoelectron circular dichroism in angle-resolved photoemission from liquid fenchone
标题：液体芬太尼角度分辨光电发射中的光电子圆二色性
链接：https://arxiv.org/abs/2201.02277
备注：Main manuscript: 11 pages, 3 figures. Supporting information: 6 pages, 7 figures
摘要：We present an experimental X-ray photoelectron circular dichroism (PECD)
study of liquid fenchone at the C 1s edge. A novel setup to enable PECD
measurements on a liquid microjet [S. Malerz et al., arXiv:2109.14365 (2021)]
was used. For the C 1s line assigned to fenchone's carbonyl carbon, a
non-vanishing asymmetry is found in the intensity of photoelectron spectra
acquired under a fixed angle in the backward-scattering plane. This experiment
paves the way towards a novel probe of the chirality of organic/biological
molecules in aqueous solution.
【29】 Reflections on the Fifth International Conference on Women in Physics
标题：关于第五届国际物理妇女大会的几点思考
链接：https://arxiv.org/abs/2201.02276
备注：None
摘要：This article describes reflections on the Fifth International Conference on
Women in Physics which was a conference attended by 215 female physicists and a
few male physicists from 49 different countries. The article focuses on the
barriers that women face in their professional advancement in physics and the
extent to which the situation is different in various countries.
【30】 LA-CoNGA physics: an Open Science Collaboration in Advanced Physics between Latin-America and Europe
标题：La-COMGA物理学：拉丁美洲和欧洲在高等物理领域的开放式科学合作
链接：https://arxiv.org/abs/2201.02256
备注：The European Physical Society Conference on High Energy Physics (EPS-HEP2021), 26-30 July 2021
摘要：LA-CoNGA physics (for Latin-American alliance for Capacity buildiNG in
Advance physics) is an ERASMUS+ project aiming to support the modernization of
university infrastructure and its pedagogical offer in advanced physics in four
Latin-American countries: Colombia, Ecuador, Per\'u and Venezuela. This project
is co-funded by the Education, Audiovisual and Culture Executive Agency of the
European Commission. This virtual teaching and research network comprises three
partner universities in Europe and eight in Latin America; high-level
scientific partners (CEA, CERN, CNRS, DESY, ICTP), and several and two
industrial partners.
During 2019 we prepared the syllabuses and selected the lecturers. In 2020
the strict lockdowns modified our pedagogical strategies. The planned model --
an eight-node network of universities made-up by local groups for discussions
-- was transformed into low-quality home participation. We simplified the
connectivity requirements to the minimum bandwidth to operate remote labs. We
also changed the lecture interaction and evaluation model, balancing the
teamwork on course projects and continuous evaluation based on class exercises.
Despite the lockdown scenario, we managed to support the needs of our
instrumentation and computing courses thanks to the contribution and enthusiasm
of our partners. With the support of 30 instructors, we gave 100 lectures to 67
students in four countries. We are now promoting the second cohort due to start
in January 2022
【31】 The effect of co-location of human communication networks
标题：人类通信网络的共址效应
链接：https://arxiv.org/abs/2201.02230
备注：19 pages, 2500 words, 5 figures. Supplementary information included as appendix
摘要：The ability to rewire ties in communication networks is vital for large-scale
human cooperation and the spread of new ideas. Especially important for
knowledge dissemination is the ability to form new weak ties -- ties which act
as bridges between distant parts of the social system and enable the flow of
novel information. Here we show that lack of researcher co-location during the
COVID-19 lockdown caused the loss of more than 4800 weak ties over 18 months in
the email network of a large North American university -- the MIT campus.
Furthermore, we find that the re-introduction of partial co-location through a
hybrid work mode starting in September 2021 led to a partial regeneration of
weak ties, especially between researchers who work in close proximity. We
quantify the effect of co-location in renewing ties -- a process that we have
termed nexogenesis -- through a novel model based on physical proximity, which
is able to reproduce all empirical observations. Results highlight that
employees who are not co-located are less likely to form ties, weakening the
spread of information in the workplace. Such findings could contribute to a
better understanding of the spatio-temporal dynamics of human communication
networks -- and help organizations that are moving towards the implementation
of hybrid work policies to evaluate the minimum amount of in-person interaction
necessary for a healthy work life.
【32】 Bi-layer voter model: Modeling intolerant/tolerant positions and bots in opinion dynamics
标题：双层投票者模型：在意见动力学中对不容忍/容忍立场和机器人进行建模
链接：https://arxiv.org/abs/2201.02218
备注：None
摘要：The diffusion of opinions in Social Networks is a relevant process for
adopting positions and attracting potential voters in political campaigns.
Opinion polarization, bias, targeted diffusion, and the radicalization of
postures are key elements for understanding voting dynamics. In particular,
social bots are a new element that can have a pronounced effect on the
formation of opinions during elections by, for instance, creating fake accounts
in social networks to manipulate elections. Here we propose a voter model
incorporating bots and radical or intolerant individuals in the decision-making
process. The dynamics of the system occur in a multiplex network of interacting
agents composed of two layers, one for the dynamics of opinions where agents
choose between two possible alternatives, and the other for the tolerance
dynamics, in which agents adopt one of two tolerance levels. The tolerance
accounts for the likelihood to change opinion in an interaction, with tolerant
(intolerant) agents switching opinion with probability $1.0$ ($\gamma \le 1$).
We find that intolerance leads to a consensus of tolerant agents during an
initial stage that scales as $\tau^+ \sim \gamma^{-1} \ln N$, who then reach an
opinion consensus during the second stage in a time that scales as $\tau \sim
N$, where $N$ is the number of agents. Therefore, very intolerant agents
($\gamma \ll 1$) could considerably slow down dynamics towards the final
consensus state. We also find that the inclusion of a fraction
$\sigma_{\mathbb{B}}^-$ of bots breaks the symmetry between both opinions,
driving the system to a consensus of intolerant agents with the bots' opinion.
Thus, bots eventually impose their opinion to the entire population, in a time
that scales as $\tau_B^- \sim \gamma^{-1}$ for $\gamma \ll
\sigma_{\mathbb{B}}^-$ and $\tau_B^- \sim 1/\sigma_{\mathbb{B}}^-$ for
$\sigma_{\mathbb{B}}^- \ll \gamma$.
【33】 Sub-surface granular dynamics in the context of oblique, low-velocity impacts into angular granular media
标题：倾斜低速撞击角状颗粒介质背景下的地下颗粒动力学
链接：https://arxiv.org/abs/2201.02585
摘要：Oblique, low-velocity impacts onto extraterrestrial terrain are an inevitable
occurrence during space exploration. We conduct two-dimensional discrete
simulations to model such impacts into a bed of triangular grains. Finite
element method provides the basis for simulation, enabling the angular grain
geometry. Our findings re-create the three classes of impact behavior
previously noted from experiments: full-stop, rollout, and ricochet
\citep*{Wright2020}. An application of Set Voronoi tessellation assesses
packing fraction at a high resolution, revealing how grains shift relative to
each other during an impact event. Calculation of Von Mises strain
distributions then reveal how grains shift relative to the overall system,
leading to the notion of the 'skin zone'. Intuition would suggest that the
region of perturbed grains would grow deeper with higher velocity impacts,
results instead show that increasing velocity may actually evoke a change in
the grains' dissipative response that boosts lateral perturbation. Finally, we
consider as a whole how sub-surface response could link with impactor dynamics
to deepen our understanding of oblique, low-velocity impact events and help to
improve mission outcomes.
【34】 In Situ Data Summaries for Flexible Feature Analysis in Large-Scale Multiphase Flow Simulations
标题：大尺度多相流模拟中柔性特征分析的现场数据汇总
链接：https://arxiv.org/abs/2201.02557
摘要：The study of multiphase flow is essential for understanding the complex
interactions of various materials. In particular, when designing chemical
reactors such as fluidized bed reactors (FBR), a detailed understanding of the
hydrodynamics is critical for optimizing reactor performance and stability. An
FBR allows experts to conduct different types of chemical reactions involving
multiphase materials, especially interaction between gas and solids. During
such complex chemical processes, formation of void regions in the reactor,
generally termed as bubbles, is an important phenomenon. Study of these bubbles
has a deep implication in predicting the reactor's overall efficiency. But
physical experiments needed to understand bubble dynamics are costly and
non-trivial. Therefore, to study such chemical processes and bubble dynamics, a
state-of-the-art massively parallel computational fluid dynamics discrete
element model (CFD-DEM), MFIX-Exa is being developed for simulating multiphase
flows. Despite the proven accuracy of MFIX-Exa in modeling bubbling phenomena,
the very-large size of the output data prohibits the use of traditional post
hoc analysis capabilities in both storage and I/O time. To address these issues
and allow the application scientists to explore the bubble dynamics in an
efficient and timely manner, we have developed an end-to-end visual analytics
pipeline that enables in situ detection of bubbles using statistical
techniques, followed by a flexible and interactive visual exploration of bubble
dynamics in the post hoc analysis phase. Positive feedback from the experts has
indicated the efficacy of the proposed approach for exploring bubble dynamics
in very-large scale multiphase flow simulations.
【35】 Numerical Simulations of Pressure Induced $sp^2$-$sp^3$ Transitions in Defect Carbon Nanotubes
标题：缺陷碳纳米管中压力诱导的$sp^2$-$sp^3$相变的数值模拟
链接：https://arxiv.org/abs/2201.02544
备注：8 pages, 13 figures
摘要：The combination of pressure and vacancy defects are investigated to find the
ideal conditions that would create meaningful $sp^3$ interlinking without
causing severe damage to the single-walled carbon nanotubes (SWCNTs). Naturally
occurring defects fail to induce interlinking. The introduction of vacancy type
defects reduces the collapse pressure of the SWCNTs. The combination of vacancy
defects, high temperature and low pressure induces $sp^3$ without causing
severe damage to the nanotubes. Structural changes caused before and after
pressurization of the nanotubes were analyzed using Raman spectroscopy.
【36】 Residual stresses and shear-induced overaging in boehmite gels
标题：薄水铝石凝胶中的残余应力和剪切诱导的过时效
链接：https://arxiv.org/abs/2201.02528
备注：5 pages, 4 figures
摘要：Colloidal gels respond like soft solids at rest, whereas they flow like
liquids under external shear. Starting from a fluidized state under an applied
shear rate $\dot\gamma_{p}$, abrupt flow cessation triggers a liquid-to-solid
transition during which the stress relaxes towards a so-called \textit{residual
stress} $\sigma_{\rm res}$ that tallies a macroscopic signature of previous
shear history. Here, we report on the liquid-to-solid transition in gels of
boehmite, an aluminum oxide, that shows a remarkable non-monotonic stress
relaxation towards a residual stress $\sigma_{\rm res}(\dot\gamma_{p})$
characterized by a dual behavior relative to a critical value $\dot\gamma_{c}$
of the shear rate $\dot\gamma_{p}$. Following shear at
$\dot\gamma_{p}>\dot\gamma_{c}$, the gel obtained upon flow cessation is
insensitive to shear history, and the residual stress is negligible. However,
for $\dot\gamma_{p}<\dot\gamma_{c}$, the gel encodes some memory of the shear
history, and $\sigma_{\rm res}$ increases for decreasing shear rate, directly
contributing to reinforcing the gel viscoelastic properties. Moreover, we show
that both $\sigma_{\rm res}$ and the gel viscoelastic properties increase
logarithmically with the strain accumulated during the shear period preceding
flow cessation. Such a shear-induced "overaging" phenomenon bears great
potential for tuning the rheological properties of colloidal gels.
【37】 Vertex finding in neutrino-nucleus interaction: A Model Architecture Comparison
标题：中微子-原子核相互作用中的顶点发现：一种模型结构比较
链接：https://arxiv.org/abs/2201.02523
摘要：We compare different neural network architectures for Machine Learning (ML)
algorithms designed to identify the neutrino interaction vertex position in the
MINERvA detector. The architectures developed and optimized by hand are
compared with the architectures developed in an automated way using the package
"Multi-node Evolutionary Neural Networks for Deep Learning" (MENNDL), developed
at Oak Ridge National Laboratory (ORNL). The two architectures resulted in a
similar performance which suggests that the systematics associated with the
optimized network architecture are small. Furthermore, we find that while the
domain expert hand-tuned network was the best performer, the differences were
negligible and the auto-generated networks performed well. There is always a
trade-off between human, and computer resources for network optimization and
this work suggests that automated optimization, assuming resources are
available, provides a compelling way to save significant expert time.
【38】 Asymmetric comb waveguide for strong interactions between atoms and light
标题：用于原子与光强相互作用的非对称梳状波导
链接：https://arxiv.org/abs/2201.02507
备注：12 pages, 6 figures
摘要：We propose a new type of periodic dielectric waveguide that provides strong
interactions between atoms and guided photons. We design an asymmetric comb
waveguide that supports a slow mode with an unusual quartic dispersion around a
zero-group-velocity point and an electric field that extends far into the air
cladding for an optimal interaction with atoms. We calculate the potential of a
two-color trap made by using blue-detuned and red-detuned guided modes. We show
that cold Rubidium atoms can be trapped as close as 100 nm from the structure
in a 1.3-mK-deep potential well. Finally, we calculate that, for atoms trapped
at this position, the emission into guided photons is largely favored. The
radiative decay rate into the guided slow mode is 10 times larger than the
free-space decay rate and the beta factor is as high as 0.88.
【39】 Optimizing broad ion beam polishing of zircaloy-4 for electron backscatter diffraction analysis
标题：用于电子背散射衍射分析的锆-4合金宽离子束抛光工艺优化
链接：https://arxiv.org/abs/2201.02501
备注：as submitted
摘要：Microstructural analysis with electron backscatter diffraction (EBSD)
involves sectioning and polishing to create a flat and preparation-artifact
free surface. The quality of EBSD analysis is often dependant on this step, and
this motivates us to explore how broad ion beam (BIB) milling can be optimised
for the preparation of zircaloy-4 with different grain sizes. We systematically
explore the role of ion beam angle, ion beam voltage, polishing duration and
polishing temperature and how this changes the surface roughness and indexing
quality. Our results provide a method to routinely prepare high-quality
Zircaloy-4 surfaces, and methods to optimise BIB polishing of other materials
for high-quality EBSD studies.
【40】 Position-dependent memory kernel in generalized Langevin equations: theory and numerical estimation
标题：广义Langevin方程的位置相关记忆核：理论和数值估计
链接：https://arxiv.org/abs/2201.02457
备注：16 pages, 3 figures
摘要：Generalized Langevin equations with non-linear forces and position-dependent
linear friction memory kernels, such as commonly used to describe the effective
dynamics of coarse-grained variables in molecular dynamics, are rigorously
derived within the Mori-Zwanzig formalism. The derivation also yields
Volterra-type equations for the kernel, which can be used for a numerical
parametrization of the model from all-atom simulations.
【41】 Simulating linear optical properties of molecules on a superconducting quantum processor
标题：在超导量子处理器上模拟分子的线性光学性质
链接：https://arxiv.org/abs/2201.02426
备注：27 pages, 5 figures, with Supplementary Information
摘要：Predictive simulation of molecular response properties such as electronic
absorption spectra is of great technological importance, but remains a
long-standing computational challenge for electronic structure methods on
classical computers. While quantum computers hold the promise to solve this
problem more efficiently in the long run, existing quantum algorithms requiring
deep quantum circuits are infeasible for near-term noisy quantum processors.
Here, we report the first ever simulation of linear optical properties of
molecules on a superconducting quantum processor enabled by a hybrid
quantum-classical approach. We demonstrate the feasibility of this approach for
computing dynamic polarizabilities of the hydrogen molecule, and then apply it
to tackle two representative problems of practical significance, including
simulating ultraviolet-visible absorption spectra of polyacenes and X-ray
absorption spectra of carbon monoxide. These results represent an initial step
towards exploring quantum computing for reliably simulating linear and
nonlinear response properties of more challenging systems in the near future.
【42】 The Dynamic Coupling of Streamers and Pseudostreamers to the Heliosphere
标题：流光和假流光与日光层的动态耦合
链接：https://arxiv.org/abs/2201.02388
摘要：The slow solar wind is generally believed to result from the interaction of
open and closed coronal magnetic flux at streamers and pseudostreamers. We use
3-dimensional magnetohydrodynamic simulations to determine the detailed
structure and dynamics of open-closed interactions that are driven by
photospheric convective flows. The photospheric magnetic field model includes a
global dipole giving rise to a streamer together with a large parasitic
polarity region giving rise to a pseudostreamer that separates a satellite
coronal hole from the main polar hole. Our numerical domain extends out to 30
solar radii and includes an isothermal solar wind, so that the coupling between
the corona and heliosphere can be calculated rigorously. This system is driven
by imposing a large set of quasi-random surface flows that capture the driving
of coronal flux in the vicinity of streamer and pseudostreamer boundaries by
the supergranular motions. We describe the resulting structures and dynamics.
Interchange reconnection dominates the evolution at both streamer and
pseudostreamer boundaries, but the details of the resulting structures are
clearly different from one another. Additionally, we calculate in situ
signatures of the reconnection and determine the dynamic mapping from the inner
heliosphere back to the Sun for a test spacecraft orbit. We discuss the
implications of our results for interpreting observations from inner
heliospheric missions, such as Parker Solar Probe and Solar Orbiter, and for
space weather modeling of the slow solar wind.
【43】 Malleable patterns from the evaporation of colloidal liquid bridge: coffee ring to the scallop shell
标题：胶体液桥蒸发的延展性模式：咖啡环到扇贝壳
链接：https://arxiv.org/abs/2201.02382
摘要：The present article highlights an approach to generate contrasting patterns
from drying droplets in a liquid bridge configuration, different from
well-known coffee rings. Reduction of the confinement distance (the gap between
the solid surfaces) leads to systematized nano-particle agglomeration yielding
to spokes-like patterns similar to those found on scallop shells instead of
circumferential edge deposition. Alteration of the confinement length modulates
the curvature that entails variations in the evaporation flux across the
liquid-vapor interface. Consequently, flow inside different liquid bridges
(LBs) varies significantly for different confinement lengths. Small confinement
lengths result in the stick-slip motion of squeezed liquid bridges. On the
contrary, the stretched LBs exhibit pinned contact lines. We decipher a
proposition that a drying liquid thin film present during dewetting near the
three-phase contact line is responsible for the aligned deposition of
particles. The confinement distance determines the height of this thin film,
and its theoretical estimations are validated against the experimental
observations using reflection interferometry, further exhibiting good agreement
(in order of magnitude). Modulating the particle size does not significantly
influence the precipitate patterns; however, particle concentration can
substantially affect the deposition patterns. The differences in deposition
patterns are attributed to the complex interplay of the gradient of evaporation
flux induced motion of contact line in combination with the drying of thin
liquid film during dewetting.
【44】 Energy transfer, discontinuities and heating in the inner solar wind measured with a weak and local formulation of the Politano-Pouquet law
标题：用波利塔诺-普奎定律的弱局域公式测量内太阳风中的能量转移、间断和加热
链接：https://arxiv.org/abs/2201.02377
备注：13 pages, 9 figures, submitted to The Astrophysical Journal
摘要：The solar wind is a highly turbulent plasma for which the mean rate of energy
transfer $\varepsilon$ has been measured for a long time using the
Politano-Pouquet (PP98) exact law. However, this law assumes statistical
homogeneity that can be violated by the presence of discontinuities. Here, we
introduce a new method based on the inertial dissipation $\Dis$ whose
analytical form is derived from incompressible magnetohydrodynamics (MHD); it
can be considered as a weak and {\it local} (in space) formulation of the PP98
law whose expression is recovered after integration is space. We used $\Dis$ to
estimate the local energy transfer rate from the \textit{THEMIS-B} and
\textit{Parker Solar Probe} (PSP) data taken in the solar wind at different
heliospheric distances. Our study reveals that discontinuities near the Sun
lead to a strong energy transfer that affects a wide range of scales $\sigma$.
We also observe that switchbacks seem to be characterized by a singular
behavior with an energy transfer varying as $\sigma^{-3/4}$, which slightly
differs from classical discontinuities characterized by a $\sigma^{-1}$
scaling. A comparison between the measurements of $\varepsilon$ and $\Dis$
shows that in general the latter is significantly larger than the former.
【45】 Roles of liquid structural ordering in glass transition, crystallization, and water's anomalies
标题：液体结构有序化在玻璃化转变、结晶和水异常中的作用
链接：https://arxiv.org/abs/2201.02334
备注：None
摘要：The liquid state is one of the fundamental and essential states of matter,
but its physical understanding is far behind the other states, such as the gas
and solid states, due to the difficulties associated with the high density
causing many-body correlations and the lack of long-range order. Significant
open problems in liquid science include glass transition, crystallization, and
water's anomalies. Austen Angell has contributed tremendously to these problems
and proposed many new concepts of fundamental importance. In this article, we
review how these concepts have influenced our work on liquid physics, focusing
on the roles of liquid structural ordering in glass transition,
crystallization, and water's anomalies.
【46】 A model of double coronal hard X-ray sources in solar flares
标题：太阳耀斑中的双冕硬X射线源模型
链接：https://arxiv.org/abs/2201.02293
备注：Submitted to ApJL
摘要：A number of double coronal X-ray sources have been observed during solar
flares by RHESSI, where the two sources reside at different sides of the
inferred reconnection site. However, where and how are these X-ray-emitting
electrons accelerated remains unclear. Here we present the first model of the
double coronal hard X-ray (HXR) sources, where electrons are accelerated by a
pair of termination shocks driven by bi-directional fast reconnection outflows.
We model the acceleration and transport of electrons in the flare region by
numerically solving the Parker transport equation using velocity and magnetic
fields from the macroscopic magnetohydrodynamic simulation of a flux rope
eruption. We show that electrons can be efficiently accelerated by the
termination shocks and high-energy electrons mainly concentrate around the two
shocks. The synthetic HXR emission images display two distinct sources
extending to $>$100 keV below and above the reconnection region, with the upper
source much fainter than the lower one. The HXR energy spectra of the two
coronal sources show similar spectral slopes, consistent with the observations.
Our simulation results suggest that the flare termination shock can be a
promising particle acceleration mechanism in explaining the double-source
nonthermal emissions in solar flares.
【47】 ScS_{2} Monolayer as a Potential Cathode Material for Alkali-ion Batteries and Beyond
标题：SCS_{2}单分子膜作为潜在的碱性离子电池正极材料
链接：https://arxiv.org/abs/2201.02268
摘要：Sc is the lightest transition metal that could help to achieve the goal of
high theoretical capacity. Hence, we here explored the performance of ScS_{2}
monolayer as a cathode material for alkali-ion batteries (Li, Na, K) and other
multi-valent metal-ion batteries (Mg, Al). Previous studies on ScS_{2} have
focused only on the fundamental electronic and magnetic properties of the
ScS_{2} monolayer, but not on its possible applications. Our first-principles
calculations show that 2D ScS_{2} is able to deliver a large theoretical
capacity of 491.36 mAh g^{-1} for alkali-ions and 324.29 mAh g^{-1} for Mg and
Al-ions while maintaining good average open-circuit voltages. We also studied
the diffusivity of these metal ions on the ScS_{2} surface which is related to
the charge/discharge rate capability of batteries. Our results suggest low
diffusion barriers for all metal ions except Al. Owing to these results, we,
therefore, believe that the ScS_{2} monolayer can be an interesting candidate
for cathode material to be used in alkali-ion batteries and beyond.
【48】 Second-Order Ultrasound Elastography with L1-norm Spatial Regularization
标题：基于L1范数空间正则化的二阶超声弹性成像
链接：https://arxiv.org/abs/2201.02226
摘要：Time delay estimation (TDE) between two radio-frequency (RF) frames is one of
the major steps of quasi-static ultrasound elastography, which detects tissue
pathology by estimating its mechanical properties. Regularized
optimization-based techniques, a prominent class of TDE algorithms, optimize a
non-linear energy functional consisting of data constancy and spatial
continuity constraints to obtain the displacement and strain maps between the
time-series frames under consideration. The existing optimization-based TDE
methods often consider the L2-norm of displacement derivatives to construct the
regularizer. However, such a formulation over-penalizes the displacement
irregularity and poses two major issues to the estimated strain field. First,
the boundaries between different tissues are blurred. Second, the visual
contrast between the target and the background is suboptimal. To resolve these
issues, herein, we propose a novel TDE algorithm where instead of L2-, L1-norms
of both first- and second-order displacement derivatives are taken into account
to devise the continuity functional. We handle the non-differentiability of
L1-norm by smoothing the absolute value function's sharp corner and optimize
the resulting cost function in an iterative manner. We call our technique
Second-Order Ultrasound eLastography with L1-norm spatial regularization
(L1-SOUL). In terms of both sharpness and visual contrast, L1-SOUL
substantially outperforms GLUE, OVERWIND, and SOUL, three recently published
TDE algorithms in all validation experiments performed in this study. In cases
of simulated, phantom, and in vivo datasets, respectively, L1-SOUL achieves
67.8%, 46.81%, and 117.35% improvements of contrast-to-noise ratio (CNR) over
SOUL. The L1-SOUL code can be downloaded from http://code.sonography.ai.
【49】 Coplanar Antenna Design for Microwave Entangled Signals Propagating in Open Air
标题：露天传输微波纠缠信号的共面天线设计
链接：https://arxiv.org/abs/2009.03021
摘要：Open-air microwave quantum communication and metrology protocols must be able
to transfer quantum resources from a fridge, where they are created, into an
environment dominated by thermal noise. Indeed, the states that carry such
quantum resources are generated in a cryostat at $T_\text{in} \simeq 10^{-2}
$~K and with $Z_\text{in} = 50 \, \Omega$ intrinsic impedance, and require an
antenna-like device to transfer them into the open air, characterized by an
intrinsic impedance of $Z_\text{out} = 377 \, \Omega$ and a temperature of
$T_\text{out} \simeq 300$ K, with minimal losses. This device accomplishes a
smooth impedance matching between the cryostat and the open air. Here, we study
the transmission of two-mode squeezed thermal states, developing a technique to
design the optimal shape of a coplanar antenna to preserve the entanglement.
Based on a numerical optimization procedure we find the optimal shape of the
impedance is exponential, and we adjust this shape to an analytical function.
Additionally, this study reveals that losses are very sensitive to this shape,
and small changes dramatically affect the outcoming entanglement, which could
have been a limitation in previous experiments employing commercial antennae.
This work will impact the fields of quantum sensing and quantum metrology, as
well as any open-air microwave quantum communication protocol, with special
application to the development of the quantum radar.
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