检索结果-南通市图书馆

Criticality-based quantum metrology in the presence of decoherence

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2023年第3期18卷 175-181页

作者： Wan-Ting He Cong-Wei Lu Yi-Xuan Yao Hai-Yuan Zhu Qing Ai Department of Physics Applied Optics Beijing Area Major LaboratoryBeijing Normal UniversityBeijing 100875China

Because quantum critical systems are very sensitive to the variation of parameters around the quantum phase transition(QPT),quantum criticality has been presented as an efficient resource for *** this paper,we address the issue whether the divergent feature of the inverted variance is realizable in the presence of noise when approaching the *** the quantum Rabi model(QRM)as an example,we obtain the analytical result for the inverted variance with single-photon *** show that the inverted variance may be convergent in time due to the *** the precision of the metrology is very sensitive to the noise,as a remedy,we propose squeezing the initial state to improve the precision under *** addition,we also investigate the criticality-based metrology under the influence of the two-photon ***,although the maximum inverted variance still manifests a power-law dependence on the energy gap,the exponent is positive and depends on the dimensionless coupling *** observation implies that the criticality may not enhance but weaken the precision in the presence of two-photon relaxation,due to the non-linearity introduced by the twophoton relaxation.

关键词： criticality quantum metrology decoherence

Entanglement Dynamics of Multipartite Systems Under decoherence from a Spin Environment

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第1X期46卷 73-76页

作者： XIE Guo-Qiu WANG An-Min MA Xiao-San Department of Modern Physics University of Science and Technology of China Hefei 230026 China Department of Electronic Information and Engineering Huangshan University Huangshan 245000 China

The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structure of quantum states, but also on the exchange couplings with environment. The decoherence-free subspaces have been identified by using the linear entropy.

关键词： entanglement dynamics decoherence a spin environment

Entanglement and discord assisted entropic uncertainty relations under decoherence

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第9期57卷 1703-1711页

作者： YAO ChunMei CHEN ZhiHua MA ZhiHao SEVERINI Simone SERAFINI Alessio Department of Physics and Electronic Science Hunan University of Arts and Science Department of Physics and Astronomy University College London Department of Science Zhijiang College Zhejiang University of Technology Centre for Quantum Technologies National University of Singapore Department of Mathematics Shanghai JiaoTong University Department of Computer Science University College London Gower Street

The uncertainty principle is a crucial aspect of quantum *** has been shown that quantum entanglement as well as more general notions of correlations,such as quantum discord,can relax or tighten the entropic uncertainty relation in the presence of an ancillary *** explored the behaviour of entropic uncertainty relations for system of two qubits—one of which subjects to several forms of independent quantum noise,in both Markovian and non-Markovian *** uncertainties and their lower bounds,identified by the entropic uncertainty relations,increase under independent local unital Markovian noisy channels,but they may decrease under non-unital *** behaviour of the uncertainties(and lower bounds)exhibit periodical oscillations due to correlation dynamics under independent non-Markovian *** addition,we compare different entropic uncertainty relations in several special cases and find that discord-tightened entropic uncertainty relations offer in general a better estimate of the uncertainties in play.

关键词： entropic uncertainty relation entanglement quantum discord decoherence Markovian and non-Markovian reservoirs

Controllable Amplification of Entanglement for Two Qutrits under decoherence

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2011年第4期55卷 569-572页

作者：郑强谢晓尧支启军任中洲 School of Mathematics and Computer Science Guizhou Normal University School of Physics and Electronics Guizhou Normal University School of Physics Nanjing University

Entanglement dynamics of a two-qutrit Heisenberg spin chain with the external magnetic fields and DM interaction under the intrinsic deeoherence is investigated. Depending on whether there is inhomogeneous magnetic field, the entanglement amplification, i.e. the phenomenon that the finally stable entanglement is bigger than that of the initial one, is found for one kind of initial states. The reasons for the controllable entanglement amplification are discussed.

关键词： entanglement DM interaction qutrit decoherence

Protecting Distribution Entanglement by Weak Measurement and Reversal under Various decoherence Sources

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2014年第4期61卷 464-468页

作者：王琼姚春梅 Hunan Province Key Laboratory of Photoelectric Information Integration Optical Manufacturing Technology Department of Physics and Electronic ScienceHunan University of Arts and Science

Protection of entanglement from disturbance of the environment is an essential task marion processing. We examine the validity and limitation of the weak measurement and reversal in quantum infor- （WMR） operation in the protection of distributed entanglement from various decoherence sources. Since the entanglement variation can be investigated analytically for an arbitrarily entangled bipartite pure state under three kinds of typical noisy quantum channels, we show explicitly that the WMR operation indeed helps for protecting distributed entanglement from ampli- tude damping and phase damping, but not for depolarizing. Bxperimental feasibility for testing our results is discussed using current laboratory techniques.

关键词： weak measurement and reversal quantum entanglement decoherence

Influence of decoherence on Interference Between Two Bose-Einstein Condensates

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2004年第1期41卷 41-44页

作者： ZENGAi-Hua KUANGLe-Man DepartmentofPhysics ShaoyangCollegeShaoyang422004China DepartmentofPhysics HunanNormalUniversityChangsha410081China

The influence of decoherence on interference between two trapped Bose-Einstein condensates with arbitraryinitial states is studied. Analytic expressions of the intensity and visibility of the interference pattern are found. It isshown that the decoherence weakens the interference intensity and decreases the visibility of the interference pattern.

关键词： Bose-Einstein condensate decoherence interference

A Numerical Study of Quantum decoherence

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2012年第6期12卷 85-108页

作者： Riccardo Adami Claudia Negulescu Dipartimento di Matematica e Applicazioni Universita di Milano Bicoccavia R.Cozzi5320125 MilanoItaly CMI/LATP(UMR 6632) Universit´e de Provence39rue Joliot Curie13453 Marseille Cedex 13France

The present paper provides a numerical investigation of the decoherence effect induced on a quantum heavy particle by the scattering with a light *** time dependent two-particle Schr¨odinger equation is solved by means of a time-splitting *** damping undergone by the non-diagonal terms of the heavy particle density matrix is estimated numerically,as well as the error in the Joos-Zeh approximation formula.

关键词： Quantum mechanics Schr¨odinger equation heavy-light particle scattering interference decoherence numerical discretization numerical analysis splitting scheme

Simulation of decoherence by Averaged Semiquantum Method

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 Computational Physics 2010年第4期7卷 718-737页

作者： Zhuo Wang Quanlin Jie Shi-Hui Zhang Department of Physics Wuhan UniversityWuhan 430072China

We investigate the dynamics of a system coupled to an environment by averaged semiquantum method. The theory origins from the time-dependent variationalprinciple (TDVP) formulation and contains nondiagonal matrix elements, thus it canbe applied to study dissipation, measurement and decoherence problems in the *** the calculation, the influence of the environment governed by differential dynamical equation is incorporated using a mean field. We have performed averaged semiquantum method for a spin-boson model, which reproduces the results from stochasticSchrodinger equation method and Hierarchical approach quite accurately. Moreover,we validate our results with noninteracting-blip approximation (NIBA) and generalized Smoluchowski equation (GSE). The problem dynamics in nonequilibrium environments has also been studied by our method. When applied to the harmonic oscillator model coupled to a heat bath with different coupling strengths and dimensionalities of the bath, we find that the loss of coherence predicted by semiquantum methodis identical to the result of master equation with different initial state (Gaussian wavepacket and superposed wave packets).

关键词： Quantum chaos spin-boson model decoherence harmonic oscillator system environment averaged semiquantum method.

Suppression of decoherence by bath ordering

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 2007年第6期16卷 1489-1504页

作者：景俊马红孺 Institute of Theoretical Physics Shanghai Jiaotong University Shanghai 200240 China

The dynamics of two coupled spins-1/2 coupled to a spin-bath is studied as an extended model of the Tessieri- Wilkie Hamiltonian. The pair of spins served as an open subsystem is prepared in one of the Bell states and the bath consisting of some spins-1/2 is in a thermal equilibrium state from the very beginning. It is found that with increasing coupling strength of the bath spins, the bath forms a resonant antiferromagnetic order. The polarization correlation between the two spins of the subsystem and the concurrence of it are recovered to some extent in the isolated subsystem. This suppression of the subsystem decoherence may be used to control the quantum devices in practical applications.

关键词： decoherence open subsystem Bell states thermal equilibrium polarization correlation