Chaos and entanglement in atomic systems interacting with photons

Abstract

The influence of chaotic behavior of coherent state (CS) parameters on entanglement dynamics in system of two level atoms and photons in cavity is investigated. The initial state of the system is chosen as factorized production of photon and atomic coherent states. To find a solution of the Schrödinger equation, we presented the time-dependent wave function in the form of a wave packet in CS representation. The phase portraits and Poincare sections for classical dynamics of CS were computed, and time dependence of the mean number of photons level populations and atomic entropy were calculated in quantum case. The analysis showed that the chaotic behavior in quantum-optical Dicke model increases the degree of entanglement in the atomic subsystem. At the same time greater entanglement is generated when selecting the initial atomic CS parameters near the center of the corresponding Poincare sections. It is considered dynamics of two identical two-level atoms in non-ideal cavity (nonideal Tavis-Cummings model). Accounting for decay showed that the generation of atomic entanglement is accompanied by the return of the initial separable state ("death" of entanglement), but this behavior with the increase of the initial parameter of the field CS is only at sufficiently small times. Influence of detuning and damping constants are considered.

Phase-difference-dependent laser-induced quantum entanglement in a pair of cubits

“…Among the phenomena recently theoretically studied theoretically it is worth mentioning the effect of dipole-dipole interaction on the quantum entanglement measure 13,14 and the influence of chaotic behavior of coherent state parameters on the entanglement dynamics in a system of two-level atoms and photons in a cavity. 15 The simplest model system relevant to quantum entanglement in quantum data processing systems is a pair of cubits, i.e., two identical two-level quantum objects. Recently 16 it was demonstrated that the presence of high intensity laser field can generate a high degree of entanglement in this system.…”