Information Entropy Squeezing Research Articles

Nonlinear interaction of a three-level atom with a two-mode field in an optomechanical cavity: Field and mechanical mode dissipations

In this paper we investigate the dynamics of f-deformed interaction (nonlinear atom-field coupling) of a three-level atom in V-configuration with a two-mode quantized field in the presence and absence of Kerr medium as well as the phonon and photon dissipations in an optomechanical cavity. We solve the associated time-dependent Schrödinger equation and arrive at the corresponding state vector at arbitrary time. In the continuation, we evaluate several nonclassical properties including atomic von Neumann entropy, atomic information entropy squeezing, sub-Poissonian statistics and atomic squeezing, numerically. Our numerical results show that, with the parameters at our disposal, we can adjust the above-mentioned properties according to our purposes. For instance, significant amount of von Neumann entropy may be achieved, in the linear and nonlinear atom-field coupling, without or even with considered dissipations. However, atomic information entropy squeezing can be observed only in the presence of nonlinear atom-field coupling by tuning the proper values of Lamb-Dicke parameter. Atomic squeezing can be seen in the presence or absence of linear and nonlinear atom-field coupling. Negative values of Mandel parameter, showing the sub-Poissonian statistics as the nonclassicality of the field can be observed with and without nonlinear atom-field coupling, however, the presence of Lamb-Dicke nonlinearity can make this effect more visible. Unless the atomic information entropy squeezing, in all above-mentioned physical phenomena stability of the evaluated parameters can be accessible via choosing appropriate parameters containing Lamb-Dicke parameter, Kerr effects, dissipation parameters, laser pumps and photon-phonon coupling.

Information Entropy Squeezing and Non-local Correlation Between a Two-Level Atom and Two-Mode Field Under the Classical Field Effect

This paper examines the squeezing on information entropy and entanglement on the basis of a quantum scheme contains two-mode interaction with time dependence of a two-level atom included external field. The proposed model is formulated by eliminating the external field after applying a certain transformation. The dynamics of information entropy squeezing and nonlocal correlation information for the system Hamiltonian are investigated. The influence of the classical field on the evolution of the squeezing and entanglement are estimated. Through the results will obtain the dynamic behavior of squeezing and entanglement is controlled using the external field.

Quantum Interference Effects on Information Phase Space and Entropy Squeezing.

Wehrl entropy and its density are used to investigate the dynamics of loss of coherence and information in a phase space for an atomic model of two-photon two-level atom coupled to different radiation reservoirs (namely, normal vacuum (NV), thermal field (TF) and squeezed vacuum (SV) reservoirs). Particularly, quantum interference (QI) effect, due to the 2-photon transition decay channels, has a paramount role in: (i) the atomic inversion decay in the NV case, which behaves as quantum Zeno and anti-Zeno decay effect; (ii) the coherence and information loss in the phase space; and (iii) identifying temporal information entropy squeezing. Results are also sensitive to the initial atomic state.

Entropy Squeezing of a Qubit Interdicting with Two-Mode Kerr Nonlinear Coupler Due to Intrinsic Damping

An analytical description for the dynamical evolution of a qubit interacting with two nonlinear Kerr oscillators pumped by optical parametric process is derived through Su(1, 1)-algebraic treatment. The role of intrinsic damping, detuning and Kerr-like Medium on the squeezing phenomenon is elucidated via information entropy squeezing. The evolutions of the interaction of the qubit with two-mode Kerr nonlinear coupler lead to the appearance the regular squeezing phenomenon during the chosen time-interval. The preserving and protecting of the qubit components from the squeezing can be controlled by the intrinsic decoherence, detuning and the Kerr-like medium effects. Where the squeezing phenomenon deteriorates with increasing the decoherence rate, whereas, the Kerr-like medium can not protect some qubit components from the squeezing.

Information quantifiers, entropy squeezing and entanglement properties of superconducting qubit-deformed bosonic field system under dephasing effect

In this paper, we present a detailed study on the evolution of some measures of nonclassicality and entanglement in the framework of the interaction between a superconducting qubit and deformed bosonic fields under decoherence effect. We compare the dynamical behavior of the different quantum quantifiers by exploiting a large set of nonlinear bosonic fields that are characterized by the deformation parameter. Additionally, we demonstrate how the connection between the appearance of the nonlinearity in the deformed field and the quantum information quantifiers. The time correlation between entropy squeezing, purity, and entanglement is examined in terms of the physical parameters involved in the whole system. Lastly, we explore the exact ranges of the physical parameters in order to combat the decoherence effect and maintain high amount of entanglement during the time evolution.

Quantum information entropy of modified Hylleraas plus exponential Rosen Morse potential and squeezed states

AbstractIn this article, some information theoretic concepts are analyzed for modified Hylleraas plus exponential Rosen Morse potential in position and momentum space. The angular and radial contributions of the information density are graphically demonstrated for different states. The entropy densities have asymmetric shape which depends on the values of quantum numbers. The information entropy is analytically obtained for ground state of the potential whereas the numerical calculations have been performed for the higher states and Bialynicki‐Birula and Mycielski inequality is tested for various states using different parameters of the potential. It is shown that the information entropy is reduced, both in position and momentum space, for careful selection of some parameters. Further, it is found that there exist eigenstates exhibiting squeezing in information entropy of modified Hylleraas plus exponential Rosen Morse and Eckart potential. Interestingly, in case of Eckart potential, the squeezed states are obtained in position as well as momentum space and are attempted to saturate for some values of the parameters.

Controlling Entropy Squeezing of Atomic Qubit in the Microwave Cavity by Manipulating the other Atomic Qubit Outside the Cavity

Using information entropy squeezing theory, we investigate the information entropy squeezing properties of atomic qubit inside a microwave cavity by manipulating the other atomic qubit outside the cavity, where two atomic qubits are initially in the Bell state. We discuss the time evolution of entropy squeezing factor for atomic qubit inside the cavity for two cases, namely before and after performing rotation operations and measuring atomic qubit outside by numerical calculation. It is shown that atomic qubit inside the cavity has always no entropy squeezing phenomenon before manipulating atomic qubit outside the cavity. However, the optimal entropy squeezing state of atomic qubit can be generated by adjusting appropriate rotation angle and choosing interaction time between atomic qubit and the cavity field. The essential idea is cutting the entanglement between atomic qubit and its environment, leading the initial decoherent state into maximal coherent superposition state. Our proposal provides a possible way for recovering coherence of single atomic qubit in noise environment.

Protecting the squeezing of a two-level system by detuning in non-Markovian environments

Squeezing of a two-level atom off-resonantly coupled to a non-Markovian reservoir is investigated. We compared two different definitions of squeezing that are based on the Heisenberg uncertainty relation and the entropy uncertainty relation and found that information entropy squeezing is more precise than variance squeezing as a measure of squeezing. Then we utilized entropy squeezing to examine the influences of the non-Markovian effect and detuning on the atomic squeezing. It is interesting to note that atomic squeezing can be protected for a long time when both the non-Markovian effect and detuning are present simultaneously. The physical mechanism is that the decay rate is suppressed much more by detuning in the non-Markovian regime than in the Markovian case.

Preparation and control of optimal entropy squeezing states for the moving atom entangment with the field under the intensity dependent coupling

运用量子信息熵理论，研究了运动二能级原子与光场依赖强度纠缠下最佳熵压缩态的制备和控制；比较了分别从基于信息熵不确定关系和海森堡不确定关系出发得出的结果；分析了制备原子最佳熵压缩态的充要条件，并进行了数值验证.考察了场模结构参数对最佳熵压缩态的影响.结果表明，信息熵压缩是对原子压缩效应的高灵敏量度；控制原子与场的相互作用时间，斩断原子和场的纠缠，选择原子的相干性，调节系统的相对位相可制备原子最佳熵压缩态；控制场模结构参数，可获得持续的原子最佳熵压缩态.

Information Entropy Squeezing for a Atom in Mode-Mode Competition System

The entropy squeezing properties for a two-level atom interacting with a two-mode field via two different competing transitions are investigated from a quantum information point of view. The influences of the initial state of the system and the relative coupling strength between the atom and the field on the atomic information entropy squeezing are discussed. Our results show that the squeezed direction and the frequency of the information entropy squeezing can be controlled by choosing the phase of the atom dipole and the relative competing strength of atom-field, respectively. We find that, under the same condition, no atomic variance squeezing is predicted from the HUR while optimal entropy squeezing is obtained from the EUR, so the quantum information entropy is a remarkable precision measure for the atomic squeezing in the considered system.

Information entropy squeezing of the atom of an arbitrary initial state via the two-photon process

From the quantum information point of view we investigate the entropy squeezing properties of a two_level atom with arbitrary initial state interacting with the coherent field via the two_photon process. The influence of the initial state of the system on the atomic information entropy squeezing is discussed. The numerical results obtained from the uncertainly relation of quantum information entropy are compared with those obtained from the uncertainly relation of Heisenberg. It is shown that the number of squeezed component of the atomic dipole, squeezed frequency, squeezed amplitude and squeezed direction of the atomic information entropy squeezing can be controlled by choosing the initial atomic distribution angle, the atomic mixing degree and the relative phase of the field mode, respectively. Quantum information entropy is a remarkable precise measure for the atomic squeezing.

Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields**The project supported by National Natural Science Foundation of China under Grant No. 19874020, the Natural Science Foundation of Hunan Province of China under Grant No. 01JJy3030, and the Scientific Research Fund of the Education Department of Hunan Province of China under Grant No. 01c260

From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number, squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle, the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.

Entropy squeezing for a two-level atom in motion interacting with a quantized field

The entropy squeezing of a two-level atom in motion interacting with a quantized field is investigated. It is shown that the information entropy squeezing is more precise than the variance squeezing as a measure of the atomic squeezing and the moving atom may exhibit long time entropy squeezing effect for some choiced system parameters.

Entropy squeezing for a two-level atom in the Jaynes-Cummings model with an intensity-depend coupling

We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

Information Entropy and Squeezing of Quantum Fluctuations in a Two-Level Atom

We study the atomic squeezing in the language of the quantum information theory. A rigorous entropy uncertainty relation which suits for characterizing the squeezing of a two-level atoms is obtained, and a general definition of information entropy squeezing in the two-level atoms is given. The information entropy squeezing of two-level atoms interacting with a single-mode quantum field is examined. Our results show that the information entropy is a superior measure of the quantum uncertainty of atomic observable, also is a remarkable good precision measure of atomic squeezing. When the population difference of two-level atom is zero, the definition of atomic squeezing based on the Heisenberg uncertainty relation is trivial, while the definition of information entropy squeezing of the atom based on the entropy uncertainty relation is valid and can provide full information on the atomic squeezing in any cases.