检索结果-南通市图书馆

Nonadiabatic geometric phase in a doubly driven two-level system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第5期32卷 314-320页

作者：刘伟新汪涛李卫东 Institute of Theoretical Physics and Department of Physics State Key Laboratory of Quantum Optics and Quantum Optics DevicesCollaborative Innovation Center of Extreme OpticsShanxi UniversityTaiyuan 030006China Department of Physics and Center of Quantum Materials and DevicesChongqing UniversityChongqing 401331China Chongqing Key Laboratory for Strongly Coupled Physics Chongqing 401331China Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Advanced Material Diagnostic Technologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118China

We study theoretically the nonadiabatic geometric phase of a doubly driven two-level system with an additional relative phase between the two driving modes introduced in. It is shown that the time evolution of the system strongly depends on this relative phase. The condition for the system returning to its initial state after a single period is given by the means of the Landau–Zener–Stückelberg–Majorana destructive interference. The nonadiabatic geometric phase accompanying a cyclic evolution is shown to be related to the Stokes phase as well as this relative phase. By controlling the relative phase, the geometric phase can characterize two distinct phases in the adiabatic limit.

关键词： two-level system geometric phase Landau–Zener–Stückelberg–Majorana interference

Steady-state relation of a two-level system strongly coupled to a many-body quantum chaotic environment

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2023年第2期75卷 56-59页

作者： Hua Yan Jiaozi Wang Wen-ge Wang Department of Modern Physics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Microscale Magnetic Resonance University of Science and Technology of ChinaHefei 230026China Department of Physics University of OsnabrückD-49076 OsnabrückGermany

We study the long-time average of the reduced density matrix(RDM)of a two-level system as the central system,which is locally coupled to a many-body quantum chaotic system as the environment,under an overall Schr?dinger evolution.A phenomenological relation among elements of the RDM is proposed for a dissipative interaction in the strong coupling regime and is tested numerically with the environment as a defect Ising chain,as well as a mixed-field Ising chain.

关键词： steady-state relations eigenstate thermalization hypothesis quantum chaos two-level system

Features of Excitation of a two-level system by Short Nonresonance Laser Pulses

在线全文

学校读者我要写书评

暂无评论

Journal of Physical Science and Application 2013年第4期3卷 269-277页

作者： Valeriy Alexandrovich Astapenko Vitaliy Anatoljevich Bagan Moscow Institute of Physics and Technology Dolgoprudnyi 141700 Moscow Region Russia

This paper is devoted to theoretical investigation of characteristic features arising during excitation by short nonresonance laser pulses. The treatment is made within the applicability of perturbation is given to the dependence of total excitation probability from eigenfrequency of TLS. Various laser pulse shapes of TLS on the pulse duration for different detuning are considered. two-level system （TLS） approach. Main attention of carrier laser frequency

关键词： Ultra-short laser pulse two-level system photo-excitation.

Exact analytical results for a two-level quantum system under a Lorentzian-shaped pulse field

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 B 2020年第6期29卷 104-108页

作者： Qiong-Tao Xie Xiao-Liang Liu College of Physics and Electronic Engineering Hainan Normal UniversityHaikou 571158China School of Physics and Electronics Central South UniversityChangsha 410083China

We investigate a two-level quantum system driven by a Lorentzian-shaped pulse *** analytical solution is presented in terms of the confluent Heun *** is shown that for specially chosen parameter conditions,there are a number of the exact analytical solutions in an explicit *** dependence of the final transition probabilities in the two levels on the system parameters is derived analytically and confirmed numerically.

关键词： exact solution Lorentzian-shaped pulse two-level system

Quantum Computation with two-level systems in Current-Biased Josephson Junction

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 855-860页

作者：余龙宝 Laboratory of Quantum Information Technology ICMP and SPTE South China Normal University

We present a feasible scheme that realizes quantum computation using the two-level systems （TLSs） in Current-biased Josephson junction （CBJJ） under the present experimental technology. Effective manipulation of the TLSs by CBJJ serving as register qubit can be obtained, such as initialization, single-qubit rotations, two-qubit gates, entanglement generation, and read out, etc. In addition, we also discuss the experimental feasibility and efficiency of the scheme.

关键词： quantum computation two-level system superconducting qubit

Weak-Coupling Theory for Low-Frequency Periodically Driven two-level systems

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第8期50卷 493-496页

作者： CHEN Ai-Xi HUANG Ke-Lin WANG Zhi-Ping Department of Applied Physics East China Jiaotong University Nanchang 330013 China

We generalize the Wu-Yang strong-coupling theory to solve analytically periodically driven two-level systems in the weak-coupling and low-frequency regimes for single- and multi-period periodic driving of continuous-wave-type and pulse-type including ultrashort pulses of a few *** also derive a general formula of the AC Stark shift suitable for such diverse situations.

关键词： two-level system weak-coupling ultrashort pulse

Quantum dynamic behaviour in a coupled cavities system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第6期21卷 26-32页

作者：彭俊邬云文李小娟 College of Physics Mechanical and Electrical EngineeringJishou University

The dynamic behaviour of the two-site coupled cavities model which is doped with ta wo-level system is investi-gated. The exact dynamic solutions in the general condition are obtained via Laplace transform. The simple analytical solutions are obtained in several particular cases, which demonstrate the clear and simple physical picture for the quan-tum state transition of the system. In the large detuning or hoppling case, the quantum states transferring between qubits follow a slow periodic oscillation induced by the very weak excitation of the cavity mode. In the large coupling case, the system can be interpreted as two Jaynes-Cummings model subsystems which interact through photon hop between the two cavities. In the case of λ≈△〉〉 g, the quantum states transition of qubits is accompanied by the excitation of the cavity, and the cavity modes have the same dynamic behaviours and the amplitude of probability is equM to 0.25 which does not change with the variation of parameter.

关键词： coupled cavities quantum dynamics behaviour detuning two-level system

Observation of EIA in closed and open caesium atomic system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2005年第4期14卷 725-728页

作者：赵建明赵延霆黄涛肖连团贾锁堂 StateKeyLaboratoryofQuantumOpticsandQuantumOpticsDevices andCollegeofPhysicsandElectronicsEngineeringShanxiUniversityTaiyuan030006China

We present an experimental study on electromagnetically induced absorption (EIA) in the closed transition of a degenerate two-level Cs atomic system. The coupling and probe lasers coupled with the transition 6S1/2F=4 →6P3/2F'=5 of caesium atom. The signal of EIA was obtained and the frequency detuning and intensity effect of the pumping laser were experimentally investigated. The EIA signal in 6S1/2 F=4 → 6P3/2 F'=4 and 6S1/2 F=4 → 6P3/2F'=3 open transitions was also obtained. As the repumping laser couples with the transition of 6S1/2 F=3 → 6P3/2F'=4, the EIA signal is increased due to the hyperfine optical pumping.

关键词： EIA caesium atom degenerate two-level system

Dynamics of 2×2 matrix non-Hermitian quantum systems on Bloch sphere

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

Communications in Theoretical Physics 2024年第4期76卷 66-71页

作者： Libin Fu Graduate School of China Academy of Engineering Physics Beijing 100193China

By casting evolution to the Bloch sphere, the dynamics of 2 × 2 matrix non-Hermitian systems are investigated in detail. This investigation reveals that there are four kinds of dynamical modes for such systems. The different modes are classified by different kinds of fixed points, namely,the elliptic point, spiral point, critical node, and degenerate point. The Hermitian systems and the unbroken PT non-Hermitian cases belong to the category with elliptic points. The degenerate point just corresponds to the systems with exceptional point(EP). The topological properties of the fixed point are also discussed. It is interesting that the topological charge for the degenerate point is two, while the others are one.

关键词： non-Hermitian quantum system two-level system dynamics on the Bloch sphere PT-symmetry fixed points