检索结果-南通市图书馆

Chinese Physics C 2024年第8期48卷 104-112页

作者： Zhi-Guo He Xiao-Bo Jin Bernd A.Kniehl Rong Li Department of Physics and Electronics School of Mathematics and PhysicsBeijing University of Chemical TechnologyBeijing 100029China II.institut für theoretische physik Universität HamburgLuruper Chaussee 14922761 HamburgGermany institut für theoretische physik Universität Regensburg93040 RegensburgGermany Center of Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of PhysicsXi’an Jiaotong UniversityXi’an 710049China institute of Theoretical Physics Xi’an Jiaotong UniversityXi’an 710049China

Within the framework of nonrelativistic-QCD factorization,we calculate both the next-to-leading-order relativistic and QCD corrections to prompt J/ψpair production,with feed-down fromψ(2S)mesons,via photon-photon collisions at future e^(+)e^(−)colliders,including the Future Circular Lepton Collider(FCC-ee),the Circular Electron Positron Collider(CEPC),and the Compact Linear Collider(CLIC).We present total cross sections and distributions in single J/ψtransverse momentum and rapidity,as well as in J/ψpair invariant *** relativistic and QCD corrections both turn out to be large and ***,the production rates are large enough for useful experimental studies.

关键词： heavy quarkonium perturbative calculation two-photon collisions

Nuclear Dynamics at the Particle Threshold

在线全文

学校读者我要写书评

暂无评论

原子核物理评论 2015年第2期32卷 129-136页

作者： Nadia Tsoneva Horst Lenske institut fur theoretische physik Universitat Gieβen

Recently, new low-energy modes of excitation called pygmy resonances have been *** distinct feature is the close connection to nuclear skin oscillations. A successful description of the pygmy resonances could be achieved in a microscopic theoretical approach which incorporates the density functional theory and QRPA formalism extended with multi-phonon degrees of freedom. The latter is found of crucial importance for the understanding of the fine structure of nuclear electric and magnetic excitations at low energies. Corresponding microscopic multi-phonon response functions are implemented in the studies of s-process of nucleosynthesis.

关键词： microscopic nuclear model density functional theory extended quasiparticle-random-phase-approximation nucleon-capture reactions stellar nucleosynthesis

Quantum Impurity Models with Coupled Cluster Method

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2010年第9期54卷 509-517页

作者： Clive Emary Tobias Brandes institut für theoretische physik

We investigate the ground-state properties of the Anderson single impurity model （finite Coulomb impurity repulsion） with the Coupled Cluster Method. We consider different CCM reference states and approximation schemes and make comparison with exact Green＇s function results for the non-interacting model and with Brillouin-Wigner perturbation theory for the full interacting model. Our results show that coupled cluster techniques are well suited to quantum impurity problems.

关键词： strongly correlated electrons Anderson model coupled-cluster method quantum impurity

Pressure and Spectral Density of Fermions at Finite Temperature

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1999年第10期16卷 709-711页

作者： HOU De-fu U.Heinz LI Jia-rong institute of Particle Physics Huazhong Normal UniversityWuhan 430079 institut fur theoretische physik Universitat RegensburgD-93040 RegensburgGermany

The pressure of a fermion system is expressed as a mass integral over the full two-point spectral densities within the real time formalism by use of the Keldysh representation for the *** simpliSes the calculation significantly and allows a Dyson *** expression is used to demonstrate that potential infrared divergences are rendered *** apply it to check the pressures of an ideal fermion gas and of a chemically non-equilibrated quantum chromodynamics plasma.

关键词： Fermi apply render

Production of the X(4014)as the Spin-2 Partner of X(3872)in e^(+)e^(-)Collisions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2024年第3期41卷 30-36页

作者： Pan-Pan Shi Vadim Baru Feng-Kun Guo Christoph Hanhart Alexey Nefediev CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Departamento de F′ısica Te′orica and IFIC Centro Mixto Universidad de Valencia-CSIC Institutos de Investigaci′on de PaternaAptdo.2208546071 ValenciaSpain institut fur theoretische physik II Ruhr-Universitat BochumD-44780 BochumGermany Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China institute for Advanced Simulation Institut fur Kernphysik and Julich Center for Hadron PhysicsForschungszentrum JulichD-52425 JulichGermany Jozef Stefan institute Jamova 391000LjubljanaSlovenia CeFEMA Center of Physics and Engineering of Advanced MaterialsInstituto Superior T′ecnicoAvenida Rovisco Pais 11049-001 LisboaPortugal

In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion *** the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).

关键词： process X(3872) Collisions

Uncertainty relations for general phase spaces

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2016年第3期11卷 51-60页

作者： Reinhard F. Werner institut fiir theoretische physik Leibniz Universitiit Hannover Germany

We describe a setup for obtain!ing uncertainty relations for arbitrary pairs of observables related by a Fourier transform. The physical examples discussed here are the standard position and momentum, number and angle, finite qudit systems, and strings of qubits for quantum information applications. The uncertainty relations allow for an arbitrary choice of metric for the outcome distance, and the choice of an exponent distinguishing, e.g., absolute and root mean square deviations. The emphasis of this article is on developing a unified treatment, in which one observable takes on values in an arbitrary locally compact Abelian group and the other in the dual group. In all cases, the phase space symmetry implies the eciuality of measurement and preparation uncertainty bounds. There is also a straightforward method for determining the optimal bounds.

关键词： uncertainty relations phase space measurement uncertainty

Weak Gravity Conjecture and extremal black holes

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 69-86页

作者： William Cottrell Gary Shiu Pablo Soler Department of Physics University of WisconsinMadison WI53706USA institut fur theoretische physik Universitat HeidelbergPhilosophenweg19Heidelberg D-69120Germany

Motivated by the desire to improve our understanding of the Weak Gravity Conjecture, we compute the one-loop correction of charged particles to the geometry and entropy of extremal black holes in 4D. We use the entropy function formalism to extend previous analysis that dealt with neutral particles, and obtain the corrections to the horizon entropy for different regimes of black hole masses. These corrections are small in general. They are furthermore reduced when supersymmetry is present, and disappear in N = 4 supergravity. We provide some speculative arguments that in a theory with only sub-extremal particles, classical Reissner-Nordstrom black holes actually possess an infinite microcanonical entropy, though only a finite amount is visible to an external observer, as shown by the horizon entropy computation.

关键词： black holes string theory entropy

Multiply Charged Anions,Maximum Charge Acceptance,and Higher Electron Affinities of Molecules,Superatoms,and Clusters

在线全文

学校读者我要写书评

暂无评论

物理化学学报 2018年第6期34卷 675-682页

作者： VON SZENTPáLY László institut fur theoretische Chemie Universitat Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany.

The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or *** this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-phase molecules,X,and the electronic stability of MCAs X^(Q-),are *** drawbacks encountered when applying computational and/or conceptual density functional theory(DFT)to MCAs are *** develop and test a different model based on the valence-state *** in DFT,the electronic energy,E(N,v_(ex)),is a continuous function of the average electron number,N,and the external potential,v_(ex),of the *** valence-state-parabola is a second-order polynomial that allows extending E(N,v_(ex))to dianions and higher *** model expresses the maximum electron acceptance,Q_(max),and the higher electron affinities,A_Q,as simple functions of the firstelectron affinity,A_1,and the ionization energy,I,of the"ancestor"***,the maximum electron acceptance is Q_(max,calc)=1+12A_1/7(I-A_1).The ground-state parabola model of the conceptual DFT yields approximately half of this value,and it is termed Q_(max,GS)=?+A_1/(I-A_1).A large variety of molecules are evaluated including fullerenes,metal clusters,super-pnictogens,super-halogens(OF_3),super-alkali species(OLi_3),and neutral or charged transition-metal complexes,AB_(m )L_n^(0/+/-).The calculated second electron affinity A_(2,calc)=A_1-(7/12)(I-A_1)is linearly correlated to the literature references A_(2,lit) with a correlation coefficient R=0.998.A_2 or A_3 values are predicted for further 24 *** appearance sizes,n_(ap)^(3-),of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.

关键词： Multiply charged negative ions Their appearance sizes Second electron affinity Third electronaffinity Conceptual density-functional theory Valence-state parabola model of electronegativity

Bistability in Coupled Oscillators Exhibiting Synchronized Dynamics

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2010年第5期53卷 815-824页

作者： O.I.Olusola U.E.Vincent A.N.Njah J.A.Olowofela Department of Physics University of Agriculture Department of Physics Lancaster University institut fur theoretische physik Technische Universitt Clausthal Department of Physics Olabisi Onabanjo University

We report some new results associated with the synchronization behavior of two coupled double-well Duffing oscillators （DDOs）. Some sufficient algebraic criteria for global chaos synchronization of the drive and response DDOs via linear state error feedback control are obtained by means of Lyapunov stability theory. The synchronization is achieved through a bistable state in which a periodic attractor co-exists with a chaotic attractor. Using the linear perturbation analysis, the prevalence of attractors in parameter space and the associated bifurcations are examined. Subcritical and supercritical Hopf bifurcations and abundance of Arnold tongues -- a signature of mode locking phenomenon are found.

关键词： chaos synchronization Duffing oscillator bistability Lyapunov stability theory

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第1期49卷 229-230页

作者： TANG Xiao-Yan Padma Kant Shukla Department of Physics Shanghai Jiao Tong University Shanghai 200240 China institut fur theoretische physik IV Fakultat fur Physik und Astronomie Ruhr-Universitat Bochum D-44870 Bochum Germany School of Physics University of KwaZulu-Natal 4000 Durban South Africa

Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented in a previous work [F. Huang, Commun. Theor. Phys. （Beijing, China） 42 （2004） 903]. A general finite transformation group is obtained based on the full Lie point symmetry, furthermore, two new types of similarity reduction solutions are obtained.

关键词： Lie symmetry similarity reductions potential vorticity equation