Generation and nonclassicality of entangled states via the interaction of two three-level atoms with a quantized cavity field assisted by a driving external classical field

摘要

The interaction of two identical three-level atoms of the types $V$, $\Xi$and $\Lambda$ with a quantized cavity field as well as a driving externalclassical field is studied. Under two certain unitary transformations, thesystem is converted to a typical form of the Jaynes-Cummings model for twothree-level atoms. The exact analytical solutions of the wave function fordifferent considered atom-field systems are exactly obtained with the help ofthe Laplace transform technique, when the atoms are initially prepared in thetopmost excited state and the quantized field is in a coherent state. In orderto examine the nonclassicality features of the deduced states, the dynamics ofthe entanglement between subsystems is discussed via two well-known measures,namely, von Neumann entropy of the reduced state and negativity. In addition,we pay attention to the temporal behaviour of quantum statistics of the photonsof the field and squeezing phenomenon. Meanwhile, the influence of the externalclassical field on the latter physical quantities is analyzed in detail. Theresults show that the mentioned quantities can be sensitively controlled viathe external classical field. Also, numerical computations imply the fact thatthe nonclassicality features in $\Xi$-type three-level atomic system is morevisible than the other two configurations. In addition, it is shown that in theparticular case of $\Lambda$-type atomic system, the rank of the reduceddensity matrix of the three-level atoms is no larger than three, so thatnegativity fully captures the entanglement of this system and that suchentanglement is distillable.