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initial-state dependence of phase behaviors in a dense active system

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Chinese Physics B 2023年第8期32卷 355-360页

作者：陈璐张博凯涂展春 Department of Physics Beijing Normal UniversityBeijing 100875China Complex Systems Division Beijing Computational Science Research CenterBeijing 100193China School of Physical Science and Technology Southwest UniversityChongqing 400715China

There are rich emergent phase behaviors in non-equilibrium active systems.Flocking and clustering are two representative dynamic phases.The relationship between both the phases is still unclear.Herein,we numerically investigate the evolution of flocking and clustering in a system consisting of self-propelled particles with active reorientation.We consider the interplay between flocking and clustering phases with different initial configurations,and observe a domain in steady state order parameter phase diagrams sensitive to the choice of initial configurations.Specifically,by tuning the initial degree of polar ordering,either a more ordered flocking or a disordered clustering state can be observed in the steady state.These results enlighten us to manipulate emergent behaviors and collective motions of an active system,and are qualitatively different from the emergence of a new bi-stable regime observed in aligned active particles due to an explicit attraction[New J.Phys.14073033(2012)].

关键词： initial state flocking clustering active systems

High-energy nuclear physics meets machine learning

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Nuclear Science and Techniques 2023年第6期34卷 9-41页

作者： Wan-Bing He Yu-Gang Ma Long-Gang Pang Hui-Chao Song Kai Zhou Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai200438China Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOE) Central China Normal UniversityWuhan430079China School of Physics and Center for High Energy Physics Peking UniversityBeijing100871China Frankfurt Institute for Advanced Studies(FIAS) 60438Frankfurt am MainGermany

Although seemingly disparate,high-energy nuclear physics(HENP)and machine learning(ML)have begun to merge in the last few years,yielding interesting results.It is worthy to raise the profile of utilizing this novel mindset from ML in HENP,to help interested readers see the breadth of activities around this intersection.The aim of this mini-review is to inform the community of the current status and present an overview of the application of ML to HENP.From different aspects and using examples,we examine how scientific questions involving HENP can be answered using ML.

关键词： Heavy-ion collisions Machine learning initial state Bulk properties Medium effects Hard probes Observables

Asymptotic-de sitter inflation in the light of the planck data

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Chinese Physics C 2018年第11期42卷 131-136页

作者： Ata Sojasi Ebrahim Yusofi Majid Mohsenzadeh Department of physics Rasht Branch Islamic Azad University Department of Physics Ayatollah Amoli Branch Islamic Azad University Department of Physics Qom Branch Islamic Azad University

Planck 2015 data, emphasize that the background geometry during inflation is not pure de Sitter, but from the slow variation of Hubble parameter during the inflationary era, it can be quasi-de Sitter. This motivates us to consider an Asymptotic-de Sitter mode function for reconstructing of initial mode and primordial power spec- trum of curvature perturbation. Using Markov Chain Monte Carlo （MCMC） method together with applying recent observational constraints from the Cosmic Microwave Background （CMB） data for the parameterized asymptotic initial mode in term of c, show some deviation from Bunch-Davies mode （c=1）. Based on Planck 2015 data release the amplitude of scalar perturbations in 68% confidence level is 10^9As=9-0.42^＋0.42 and deviation from Bunch-Davies mode is - 0.05, i.e. c,- 1.05. In this parametrization, the CMB power spectrum of our model shows more red-tilt in comparison with ACDM model. Furthermore, we found upper limits for tensor-to-scaler ratio with different pivot scales.

关键词： inflation cosmic microwave background initial state

Higher order corrections to asymptotic-de Sitter inflation

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Chinese Physics C 2017年第8期41卷 112-117页

作者： M.Mohsenzadeh E.Yusofi Department of Physics Qom BranchIslamic Azad UniversityQomIran Department of Physics Ayatollah Amoli BranchIslamic Azad UniversityAmolMazandaranIrana School of Astronomy Institute for Research in Fundamental Sciences(IPM)P.O.Box 19395-5531TehranIran

Since trans-Planckian considerations can be associated with the re-definition of the initial vacuum, we investigate further the influence of trans-Planckian physics on the spectra produced by the initial quasi-de Sitter（d S） state during inflation. We use the asymptotic-d S mode to study the trans-Planckian correction of the power spectrum to the quasi-d S inflation. The obtained spectra consist of higher order corrections associated with the type of geometry and harmonic terms sensitive to the fluctuations of space-time（or gravitational waves） during inflation.As an important result, the amplitude of the power spectrum is dependent on the choice of c, i.e. the type of spacetime in the period of inflation. Also, the results are always valid for any asymptotic d S space-time and particularly coincide with the conventional results for d S and flat space-time.

关键词： initial state trans-Planckian effects inflation

Large angular scale CMB anisotropy from an excited initial mode

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Chinese Physics C 2016年第7期40卷 85-89页

作者： A.So jasi M.Mohsenzadeh E.Yusofi Department of Physics Rasht Branch Islamic Azad University Department of Physics Qom Branch Islamic Azad University Department of Physics Ayatollah Amoli Branch Islamic Azad University

According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect observables such as the CMB power spectrum. In this study a quasi-de Sitter inflationary background with approximate de Sitter mode function built over the Bunch-Davies mode is applied to investigate the scale-dependency of the CMB anisotropy. The recent Planck constraint on spectral index motivated us to examine the effect of a new excited mode function （instead of pure de Sitter mode） on the CMB anisotropy at large angular scales. In so doing, it is found that the angular scale-invariance in the CMB temperature fluctuations is broken and in the limit l 〈 200 a tiny deviation appears. Also, it is shown that the power spectrum of CMB anisotropy is dependent on a free parameter with mass dimension H 〈〈 M＊〈 Mp and on the slow-roll parameter ε.

关键词： initial state power spectrum CMB anisotropy

Arranging transient process used in iterative learning control system

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Journal of Pharmaceutical Analysis 2009年第1期21卷 42-45页

作者： Li-chuan Hui, Hui Lin School of Automation, Northwestern Polytechnical University, Xi’an 710129, China. School of Automation Northwestern Polytechnical University Xi'an 710129 China

Considering the same initial state error in each repetitive operation in the iterative learning system, a method of arranging the transient process is given. During the current iteration, the system will track the transient function firstly, and then the expected trajectory. After several iterations, the learning system output will trend to the arranged curve, which has avoided the effect of the initial error on the controller. Also the transient time can be changed as you need, which makes the designing simple and the operation easy. Then the detailed designing steps are given via the robot system. At last the simulation of the robot system is given, which shows the validity of the method.

关键词： iterative learning initial state transient process robot system

More relaxed conditions for model predictive control with guaranteed stability

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控制理论与应用（英文版） 2005年第2期3卷 189-194页

作者： Bin LIU Yugeng XI Institute of Automation Shanghai Jiaotong University Shanghai 200030 China

For the model predictive controller, terminal state satisfying a certain inequality can guarantee the stability but it is somewhat conservative. In this paper, we give a more relaxed stability condition by considering the effect of the initial state. Based on that we propose an algorithm to guarantee that the closed loop system is asymptotically stable. Finally, the conclusions are verified by a simttlation.

关键词： Model predictive control Stability initial state Terminal state set