期刊文献+
共找到38篇文章
< 1 2 >
每页显示 20 50 100
Functional Integrals and Quantum Fluctuations on Two-Dimensional Noncommutative Space-Time 被引量:5
1
作者 YAN Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第9期445-448,共4页
The generalized Thirring model with impurity coupling is defined on two-dimensional noncommutativespace-time,a modified propagator and free energy are derived by means of functional integrals method.Moreover,quantum f... The generalized Thirring model with impurity coupling is defined on two-dimensional noncommutativespace-time,a modified propagator and free energy are derived by means of functional integrals method.Moreover,quantum fluctuations and excitation energies are calculated on two-dimensional black hole and soliton background. 展开更多
关键词 functional integrals quantum fluctuations noncommutative space-time
下载PDF
New Way to Quantize Time-Dependent RLC Electric Circuit and Quantum Fluctuations
2
作者 梁麦林 袁兵 赵林 《Transactions of Tianjin University》 EI CAS 2002年第1期8-11,共4页
According to the physical mechanism of the generation of the resistance or the electron phonon interaction, a new method is proposed to quantize the RLC electric circuit. Calculations show that the quantum fluctuatio... According to the physical mechanism of the generation of the resistance or the electron phonon interaction, a new method is proposed to quantize the RLC electric circuit. Calculations show that the quantum fluctuations under this new quantization are smaller than those by the traditional effective Hamiltonian method. And squeezed states can be generated if the inductance and capacity are time dependent. Meanwhile, the shortcoming of the traditional method that the electric charge and current will vanish in the long time limit is overcome. 展开更多
关键词 RLC electric circuit lattice oscillation quantum fluctuation squeezed state
下载PDF
Properties of ground state and anomalous quantum fluctuations in one-dimensional polaron-soliton systems-the effects of electron-two-phonon interaction and non-adiabatic quantum correlations
3
作者 罗质华 曹锡金 余超凡 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第6期372-383,共12页
Based on the Holstein model Hamiltonian of one-dimensional molecular crystals, by making use of the expansion approach of the correlated squeezed-coherent states of phonon instead of the two-phonon coherent state expa... Based on the Holstein model Hamiltonian of one-dimensional molecular crystals, by making use of the expansion approach of the correlated squeezed-coherent states of phonon instead of the two-phonon coherent state expansion scheme, the properties of the ground state and the anomalous quantum fluctuations are investigated in a strongly coupled electron-phonon system with special consideration of the electron-two-phonon interaction. The effective renormalization (ai) of the displacement of the squeezed phonons with the effect of the squeezed-coherent states of phonon and both the electron-displaced pbonon and the polaron-squeezed phonon correlations have been combined to obtain the anomalous quantum fluctuations for the corrections of the coherent state. Due to these non-adiabatic correlations, the effective displacement parameter ai is larger than the ordinary parameter ai (0) In comparison with the electron-one-phonon interaction (g) corrected as oig, we have found the electron-two-phonon interaction (gl) corrected as ai2gi is enhanced significantly. For this reason, the ground state energy (E(2)) contributed by the electron-two-phonon interaction is more negative than the single-phonon case (E01)) and the soliton solution is more stable. At the same time, the effects of the electron-two-phonon interaction greatly increase the polaron energy and the quantum fluctuations. Furthermore, in a deeper level, we have considered the effect of the polaron-squeezed phonon correlation (f-correlation). Since this correlation parameter f 〉 1, this effect will strengthen the electron-one and two-phonon interactions by fai9 and f2ai2g1, respectively. The final results show that the ground state energy and the polaron energy will appear more negative further and the quantum fluctuations will gain further improvement. 展开更多
关键词 correlated squeezed-coherent state expansion electron-two-phonon interaction nonadiabatic correlations and renormalized phonon displacement anomalous quantum fluctuations polaron-squeezed phonon correlation
下载PDF
Quantum fluctuations of the antiferro-antiferromagnetic double-layer
4
作者 姜伟 朱程博 +1 位作者 于桂红 罗永祥 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第8期3547-3550,共4页
This paper stuides the magnetization and quantum fluctuations of an antiferro-antiferromagnetic (AF-AF) doublelayer at zero temperature. It is found that the exchanges and anisotropy constants affect the quantum flu... This paper stuides the magnetization and quantum fluctuations of an antiferro-antiferromagnetic (AF-AF) doublelayer at zero temperature. It is found that the exchanges and anisotropy constants affect the quantum fluctuations of spins. If the anisotropy exists, there will be no acoustic energy branch in the system. The anisotropy constant, antiferromagnetic intralayer and interlayer coupling have important roles in a balance of the quantum competition. 展开更多
关键词 quantum fluctuations antiferromagnetic double-layer MAGNETIZATION
下载PDF
Critical exponents of ferroelectric transitions in modulated SrTiO_3:Consequences of quantum fluctuations and quenched disorder
5
作者 王景雪 刘美风 +1 位作者 颜志波 刘俊明 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期516-526,共11页
The ferroelectric transitions of several SrTiO3-based ferroelectrics are investigated experimentally and theoretically, with special attention to the critical scaling exponents associated with the phase transitions, i... The ferroelectric transitions of several SrTiO3-based ferroelectrics are investigated experimentally and theoretically, with special attention to the critical scaling exponents associated with the phase transitions, in order to understand the competition among quantum fluctuations (QFs), quenched disorder, and ferroelectric ordering. Two representative systems with sufficiently strong QFs and quenched disorders in competition with the ferroelectric ordering are investigated. We start from non-stoichiometric SrTiO3(STO) with the Sr/Ti ratio deviating slightly from one, which is believed to maintain strong QFs. Then, we address Ba/Ca co-doped Sr1-x(Ca0.6389Ba0.3611)xTiO3(SCBT) with the averaged Sr-site ionic radius identical to the Sr2+ ionic radius, which is believed to offer remarkable quenched disorder associated with the Sr-site ionic mismatch. The critical exponents associated with polarization P and dielectric susceptibility ε, respectively, as functions of temperature T close to the critical point Tc, are evaluated. It is revealed that both non-stoichiometric SrTiO3 and SCBT exhibit much bigger critical exponents than the Landau mean-field theory predictions. These critical exponents then decrease gradually with increasing doping level or deviation of Sr/Ti ratio from one. A transverse Ising model applicable to the Sr-site doped STO (e.g., Sr1-xCaxTiO3) at low level is used to explain the observed experimental data. It is suggested that the serious deviation of these critical exponents from the Landau theory predictions in these STO-based systems is ascribed to the significant QFs and quenched disorder by partially suppressing the long-range spatial correlation of electric dipoles around the transitions. The present work thus sheds light on our understanding of the critical behaviors of ferroelectric transitions in STO in the presence of quantum fluctuations and quenched disorder, whose effects have been demonstrated to be remarkable. 展开更多
关键词 critical exponents quantum fluctuations ferroelectric phase transitions
下载PDF
Quantum fluctuations of mesoscopic damped double resonance RLC circuit with mutual capacitance-inductance coupling 被引量:12
6
作者 徐兴磊 李洪奇 王继锁 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第8期2462-2470,共9页
Based on the scheme of damped harmonic oscillator quantization and thermo-field dynamics (TFD), the quantization of mesoscopic damped double resonance RLC circuit with mutual capacitance-inductance coupling is propo... Based on the scheme of damped harmonic oscillator quantization and thermo-field dynamics (TFD), the quantization of mesoscopic damped double resonance RLC circuit with mutual capacitance-inductance coupling is proposed. The quantum fluctuations of charge and current of each loop in a squeezed vacuum state are studied in the thermal excitation case. It is shown that the fluctuations not only depend on circuit inherent parameters, but also rely on excitation quantum number and squeezing parameter. Moreover, due to the finite environmental temperature and damped resistance, the fluctuations increase with the temperature rising, and decay with time. 展开更多
关键词 mesoscopic double resonance RLC circuit linear transformation thermal excitation state quantum fluctuation
下载PDF
Non-Zero Temperature Evolution of the Quantum Fluctuations in Time-Dependent Inductive-Capacitive Coupled Circuit
7
作者 梁麦林 袁兵 《Journal of Shanghai University(English Edition)》 CAS 2002年第3期203-206,共4页
For time dependent inductive capacitive coupled circuits, the quantum fluctuations in the component circuits and the coupling part are computed. Generation of squeezing and the different effects of inductance and ca... For time dependent inductive capacitive coupled circuits, the quantum fluctuations in the component circuits and the coupling part are computed. Generation of squeezing and the different effects of inductance and capacitance couplings on the quantum fluctuations are rigorously given. Meanwhile, the thermal effects are included. 展开更多
关键词 coupled circuit quantum fluctuation SQUEEZING thermal effect.
下载PDF
Escape of Brownian particles and stochastic resonance with low-temperature quantum fluctuations
8
作者 ZENG ChunHua WANG Hua HU JianHang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第8期1388-1393,共6页
In this paper, we investigate the escape of Brownian particles and stochastic resonance (SR) with low-temperatures quantum fluctuations by using the quantum Smoluchowski equations at low-temperature. Two specific exam... In this paper, we investigate the escape of Brownian particles and stochastic resonance (SR) with low-temperatures quantum fluctuations by using the quantum Smoluchowski equations at low-temperature. Two specific examples have been considered: one is the example of bistable system, and the other is the example of metastable system. The explicit expressions of the mean-first passage time (MFPT) and signal-to-noise ratio (SNR) for both specific examples are obtained, respectively. Based on the numerical computations, we compare the quantum case with its classical counterpart. Our research results show that: (i) the quantum effect accelerates the escape of the Brownian particle in comparison with the classical result and (ii) the quantum effect enhances the SR in the SNR as a function of β for a bistable system (i.e., β = 1/kBT, kB is the Boltzmann constant and T is the temperature), while for a metastable system, the β amplifies the quantum effects, and the quantum effect weakens the SNR as a function of β. 展开更多
关键词 quantum fluctuations quantum Smoluchowski equations mean-first passage time stochastic resonance
原文传递
Quantum Fluctuation of a Mesoscopic Inductance Coupling Circuit at Finite Temperature 被引量:16
9
作者 SONGTong-Qiang ZHUYue-Jin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第4期447-450,共4页
We study the quantization of mesoscopic inductance coupling circuit and discuss its time evolution. Bymeans of the thermal field dynamics theory we study the quantum fluctuation of the system at finite temperature.
关键词 mesoscopic inductance coupling circuit quantum fluctuation Joule heat effects
下载PDF
Quantum Fluctuation Properties in Mesoscopic Josephson Junction
10
作者 杨胡江 邵彬 邹健 《Journal of Beijing Institute of Technology》 EI CAS 2002年第4期429-432,共4页
An effective bosonic Hamiltonian describing the interaction of a mesoscopic Josephson junction with a quantized radiation field is studied. It is shown that when the field is initially in a coherent state and the junc... An effective bosonic Hamiltonian describing the interaction of a mesoscopic Josephson junction with a quantized radiation field is studied. It is shown that when the field is initially in a coherent state and the junction initially in its lowest energy level state, the state of the coupled field-mesoscopic Josephson junction system can evolve to a squeezed state. A detailed analysis about the quantum fluctuation of the coupled system is given. 展开更多
关键词 mesoscopic Josephson junction squeezed state quantum fluctuation
下载PDF
Quantum Squeezing of Dark Solitons in Optical Fibers 被引量:1
11
作者 G.R.Honarasa M.Hatami M.K.Tavassoly 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第8期322-326,共5页
The quantum theory of dark soliton propagation in fibers is studied based on the linearization approximation. Then the uncertainties in photon number, phase, position (time) and momentum of quantized dark solitons a... The quantum theory of dark soliton propagation in fibers is studied based on the linearization approximation. Then the uncertainties in photon number, phase, position (time) and momentum of quantized dark solitons are calculated. Finally, the squeezing of the dark soliton is investigated by using homodyne detection and compared with bright soliton case. 展开更多
关键词 SQUEEZING dark soliton quantum nonlinear Schrodinger equation quantum fluctuation
下载PDF
Resonant tunneling and quantum fluctuation in a driven triple-well system
12
作者 卢伟涛 王顺金 张华 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第2期35-42,共8页
The influence of parameters such as the strength and frequency of a periodic driving force on the tunneling dynamics is investigated in a symmetric triple-well potential. It is shown that for some special values of th... The influence of parameters such as the strength and frequency of a periodic driving force on the tunneling dynamics is investigated in a symmetric triple-well potential. It is shown that for some special values of the parameters, tunneling could be enhanced considerably or suppressed completely. Quantum fluctuation during the tunneling is discussed as well and the numerical results are presented and analysed by virtue of Floquet formalism. 展开更多
关键词 triple-well potential non-resonant tunneling resonant tunneling Floquet theorem quantum fluctuation
下载PDF
Effects of anisotropy on quantum fluctuation of a three-layer system with mutisublattice
13
作者 姜伟 张凡 +1 位作者 关宏宇 梁吉艳 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第12期499-503,共5页
The quantum fluctuations of a three-layer Heisenberg model with six sublattices are studied by the retarded Green's function method and the spin-wave theory. The effects of anisotropy on the quantum fluctuations at z... The quantum fluctuations of a three-layer Heisenberg model with six sublattices are studied by the retarded Green's function method and the spin-wave theory. The effects of anisotropy on the quantum fluctuations at zero temperature are discussed. The results show that the interlayer anisotropy plays an important role in balancing the quantum competitions. 展开更多
关键词 multisublattice three-layer quantum fluctuation effects of anisotropy
下载PDF
Quantum Fluctuation Properties of Polariton System in Thermal Vacuum State Field
14
作者 邵彬 余天胜 +1 位作者 邹健 曾天海 《Journal of Beijing Institute of Technology》 EI CAS 2004年第1期96-99,共4页
Using the theory of thermal field dynamics (TFD), a model polariton system is investigated and the squeezing properties of the polariton system at finite temperature is discussed. It is shown that when the photon fiel... Using the theory of thermal field dynamics (TFD), a model polariton system is investigated and the squeezing properties of the polariton system at finite temperature is discussed. It is shown that when the photon field is initially in a thermal vacuum state and the phonon initially in its lowest energy level state (the vacuum state), the phonon, photon and also the polariton system can exhibit nonclassical behaviour. 展开更多
关键词 POLARITON thermal vacuum state quantum fluctuation squeezed state
下载PDF
Quantum backreaction of quantum fluid in Bose Einstein condensates
15
作者 徐岩 熊祖周 +2 位作者 陈兵 李照鑫 谭磊 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第11期4734-4737,共4页
In this paper, with the full field operator ψ expressed in terms of a particle-number-conserving mean-field ansatz, we investigate the dynamical behaviour of Bose-Einstein condensates from microscopic physics. Includ... In this paper, with the full field operator ψ expressed in terms of a particle-number-conserving mean-field ansatz, we investigate the dynamical behaviour of Bose-Einstein condensates from microscopic physics. Including the first-order term correction from single-particle excitation and the remaining higher-order term correction from collective excitations simultaneously, we obtain the formulation for a closed local expression of quantum backreaction Q, and discuss the influence on static Bose-Einstein condensates. Even though the quantum backreaction is small, it still has some influence on its dynamics. 展开更多
关键词 Bose-Einstein condensate quantum fluctuation mean-field theory
下载PDF
Time Evolution,Dynamical Quantum Fluctuation and High-Order Squeezing Feature in Polariton System——Ⅰ
16
作者 梁国栋 余晓敏 余超凡 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第11期913-924,共12页
We have set up a new reduced model Hamiltonian for the polariton system, in which the nonlinear interaction contains the rotating term k l ( a + b + ab+) and the attractive two-mode squeezed coupling - k2 ( a ... We have set up a new reduced model Hamiltonian for the polariton system, in which the nonlinear interaction contains the rotating term k l ( a + b + ab+) and the attractive two-mode squeezed coupling - k2 ( a + b+ + ab ) . The dynamical evolution of this system has been solved and the nonclassical features relevant to the second-order and high-order squeezing have been obtained in an analytical form. For the first time, in contrast to the existing result, we have confirmed for the phonon field that the attractive two-mode squeezed interaction will not only result in the second-order and high-order squeezing in X-component with the time evolution, but also in time average. Furthermore, the phenomena of collapse and revival of inversion will occur as well in the time evolution of the average number of photon and phonon, as also in the second-order and high-order squeezing of photon field, particularly, in the high-order squeezing of phonon field. 展开更多
关键词 dynamic evolution of polariton system quantum fluctuation high-order squeezing
下载PDF
Quantum fluctuation of entanglement for accelerated two-level detectors
17
作者 Si-Xuan Zhang Tong-Hua Liu +3 位作者 Shuo Cao Yu-Ting Liu Shuai-Bo Geng Yu-Jie Lian 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第5期149-154,共6页
It is well known that the quantum fluctuation of entanglement(QFE) between Unruh–De Witt detector(modeled by a two-level atom) is always investigated in a relativistic setting. However, both of the Unruh radiation an... It is well known that the quantum fluctuation of entanglement(QFE) between Unruh–De Witt detector(modeled by a two-level atom) is always investigated in a relativistic setting. However, both of the Unruh radiation and quantum fluctuation effects play an important role in precise measurements of quantum entanglement. In this paper, we have quantitatively analyzed how the relativistic motion affects the QFE for two entangled Unruh–De Witt detectors, one of which is accelerated and interacting with the neighbor external scalar field. Our results show that the QFE, which initially increases by the Unruh thermal noise, will suddenly decay when the acceleration reaches to a considerably large value. Therefore, the relativistic effect will lead to non-negligible QFE effect. We also find that the initial QFE(without acceleration effect) reaches its minimum value at the maximally entangled state and the separable state. More importantly, our analysis demonstrates that although the QFE has a huge decay when the acceleration is greater than ~ 0.96, the ratio of △E/C is still very large, due to the simultaneous decay of concurrence to a very low value. Finally, enlightened by the well-known equivalence principle,we discuss the possibility of applying the above findings to the dynamics of QFE under the influence of gravitation field. 展开更多
关键词 relativistic quantum information quantum fluctuation Unruh effect
下载PDF
Intensity Correlation Function and Associated Relaxation Time of a Saturation Laser Model with Correlated Noises 被引量:1
18
作者 朱平 陈世波 梅冬成 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第1期29-31,共3页
We investigate the intensity correlation function C(s) and its associated relaxation time Tc for a saturation model of single-mode laser with correlated noises. The expressions of O(s) and Tc are derived by means ... We investigate the intensity correlation function C(s) and its associated relaxation time Tc for a saturation model of single-mode laser with correlated noises. The expressions of O(s) and Tc are derived by means of the projection operator method, and effects of correlations between an additive noise and a multiplicative noise are discussed by numerical calculation. Based on the calculated results, it is found that the correlation strength A between the additive noise and the multiplicative noise can enhance the fluctuation decay of the laser intensity. 展开更多
关键词 STEADY-STATE ANALYSIS DYE-LASER MULTIPLICATIVE NOISE COLORED-NOISE WHITE-NOISE PROCESSES DRIVEN quantum fluctuations TRANSIENT PROCESS STATISTICS SYSTEM
下载PDF
Bunching and Antibunching in Cavity QED
19
作者 H.Jabri H.Eleuch 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第7期134-138,共5页
We study the statistics of the emitted filed from Rydberg atom confined inside a microcavity and interacting with a pump laser in the strong coupling regime. We explore the manifestation of the antibunching in connect... We study the statistics of the emitted filed from Rydberg atom confined inside a microcavity and interacting with a pump laser in the strong coupling regime. We explore the manifestation of the antibunching in connection with the internal system parameters. 展开更多
关键词 quantum fluctuations quantum noise photon statistics cavity quantum electrodynamics
下载PDF
Density Matrix for Mesoscopic Distributed Parameter Circuits
20
作者 JIYing-Hua WANGQi LUOHai-Mei LEIMin-Sheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3期547-550,共4页
Under the Born-von-Karmann periodic boundary condition, we propose a quantization scheme for non-dissipative distributed parameter circuits (i.e. a uniform periodic transmission line). We find the unitary operator for... Under the Born-von-Karmann periodic boundary condition, we propose a quantization scheme for non-dissipative distributed parameter circuits (i.e. a uniform periodic transmission line). We find the unitary operator for diagonalizing the Hamiltonian of the uniform periodic transmission line. The unitary operator is expressed in a coordinate representation that brings convenience to deriving the density matrix rho(q,q',beta). The quantum fluctuations of charge and current at a definite temperature have been studied. It is shown that quantum fluctuations of distributed parameter circuits, which also have distributed properties, are related to both the circuit parameters and the positions and the mode of signals and temperature T. The higher the temperature is, the stronger quantum noise the circuit exhibits. 展开更多
关键词 mesoscopic distributed parameter circuits density matrix quantum fluctuations
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部