A quantum optics model is considered where the cavity field interacts with two coupled atoms. The time-dependent wave function is obtained and used to derive the density matrix from which we discussed some statistical properties for the present system. The atom-atom entanglement, atoms-cavity entanglement, entropy and variance squeezing, the Pegg-Barrnet phase and the fidelity are discussed with the effects of the initial conditions, atom-atom coupling and the detuning parameter displayed. It is shown that an increase in the value of the atom-atom coupling parameter leads to an increase in the degree of entanglement. Numerical results show that under some conditions the phenomena of entanglement and the collapses and the revivals emerge. Nonclassical properties are demonstrated by means of the field quantum statistical characteristics, such as photon-number distribution, Husimi, Wigner and Glauber-Sudarshan quasidistributions and the corresponding variances.
A quantum optics model is considered where the cavity field interacts with two coupled atoms. The time-dependent wave function is obtained and used to derive the density matrix from which we discussed some statistical properties for the present system. The atom-atom entanglement, atoms-cavity entanglement, entropy and variance squeezing, the Pegg-Barrnet phase and the fidelity are discussed with the effects of the initial conditions, atom-atom coupling and the detuning parameter displayed. It is shown that an increase in the value of the atom-atom coupling parameter leads to an increase in the degree of entanglement. Numerical results show that under some conditions the phenomena of entanglement and the collapses and the revivals emerge. Nonclassical properties are demonstrated by means of the field quantum statistical characteristics, such as photon-number distribution, Husimi, Wigner and Glauber-Sudarshan quasidistributions and the corresponding variances.
In this paper, we study the interaction between the time-dependent field and a two-level atom with one mode electromagnetic field. We consider that the field of photons is assumed to be coupled with modulated coupling parameter which depends explicitly on time. It is shown that the considered model can be reduced to a well-known form of the time-dependent generalized Jaynes–Cummings model. Under special initial conditions, in which the atom and the field are prepared in the excited and the coherent states, respectively, the explicit time evolution of the wave function of the entire system is analytically obtained. Our proposal has many advantages over the previous optical schemes and can be realized in several multiple experiments, such as trapped ions and quantum electrodynamics cavity. The influence of the time-dependent field parameter on the collapses-revivals, the normal squeezing of the radiation, the anti-bunching of photons and the entanglement phenomena for the considered atomic system is examined. The linear entropy, the von Neumann entropy are used to quantify entanglement in the quantum systems. We noticed that these phenomena are affected by the existence of both the time-dependent coupling field and detuning parameters.
In this paper, we follow the model presented in our previous work [J. Opt. Soc. Am. B30, 1109 (2013)], in which the interaction between a Λ-type three-level atom and a quantized two-mode radiation field in a cavity in the presence of nonlinearities was studied. After giving a brief review of the procedure for obtaining the state vector of the atom-field system, we investigated some further interesting and important physical features of the whole system state, which are of particular interest to the quantum optics field of research, i.e., the number-phase entropic uncertainty relation (based on the two-mode Pegg–Barnett formalism) and a few of the nonclassicality signs that consist of sub-Poissonian statistics, Cauchy–Schwartz inequality, and two types of squeezing phenomena. During our presentation, the effects of intensity-dependent coupling, deformed Kerr medium, and the detuning parameters on the depth and domain of each of the mentioned nonclassical criteria of the considered quantum system are described in detail. The results show that each of the mentioned nonclassicality aspects can be obtained by appropriately choosing the related parameters.
Abstract In this paper the interaction of a three-level atom in V -configuration with a two-mode quantized field in cavity optomechanics is studied. To achieve the purpose, we first deduce the effective Hamiltonian and evaluate the explicit time-dependent form of the state vector of the whole system by choosing special initial conditions for atom, field and the oscillatory mirror. Interestingly, we can obtain the time evolution of atomic linear entropy, population inversion, quantum statistics and squeezing, both analytically and numerically. The results show that the entanglement between the atom and the subsystem of field and mirror, and all above-mentioned physical quantities can be appropriately controlled by the initial atom-field state condition, the parameters of cavity optomechanics as well as atom-field coupling strengths. In particular, the appearance of collapse-revival phenomenon in the entanglement and quantum photon statistics, also the full sub-Poissonian statistics in the two modes of field as well as in the mechanical mode of optomechanical system are noticeable features of the work.
A quantum model for the interaction between asymmetric two two-level atoms and an electromagnetic field is presented. The [Formula: see text]-photon processes and atom–atom interaction are considered in this quantum model. The wavefunction for asymmetric case of the proposed model is obtained analytically. While, the explicit analytical formula of the wavefunction for symmetric case was calculated in previous works. Initially, the electromagnetic field is in the coherent state and two two-level atoms are identical in the excited states. For the proposed model, some statistical aspects are obtained, such as the linear entropy, atomic population inversion, entropy squeezing, atomic variance and von Neumann entropy. The evaluations of these statistical properties are discussed for the variation in the detuning parameters. Moreover, the nonclassical effects for atom–atom interaction are observed.
The interaction between two Ξ -type three-level atoms and a single-mode cavity field in the intensity-dependent coupling regime has been studied. The exact analytical solution of the wave function for the considered atom–field system has been obtained by using the Laplace transform technique when the atoms are initially prepared in the excited state and the field is in a coherent state. The presented structure has the potential ability to generate various new classes of entangled states depending on the chosen nonlinearity function. Two forms of intensity-dependent coupling as well as constant coupling are considered. Some important physical properties such as quantum entanglement, quantum statistics and quadrature squeezing of the corresponding states are investigated, numerically, by which the nonclassicality features of the produced entangled state are well-established. In particular, the effect of intensity-dependent coupling on the degree of entanglement between different bipartite partitions of the system (that is, 'atom atom'-field and 'field atom'-atom) using the linear entropy is investigated. At the same time, by paying attention to the negativity as a useful measure, the entanglement between the two atoms is studied in detail.
We consider the system which is composed of a two-level atom and a two-mode cavity,and two modes are coupled in the cavity.The evolution of the state vector of the system is given.The squeezing,antibunching effect and the photon number statistical distribution of two-mode field are investigated.First,through calculating the fluctuations of two quadrature components of the field,we get that a-mode and b-mode of two-mode field do not both display squeezing.Second,by calculating second-order correlation function of two-mode field,the results show that a-mode and b-mode of two-mode field both display antibunching effects,and there is anti-correlation between the two modes.Third,by means of the numerical calculations,we plot evolution curves of Mandel Q function for different values of the coupling constants between two modes.Through comparing these curves,the influence of coupling constant between two modes on the photon number statistical distribution of the field is discussed.The evolution curves of Mandel Q function show that the two-mode cavity field displays sub-Poisson distribution.Moreover,the sub-Poisson distribution is weakened with increasing of the coupling constant between two modes.