Entangling operations in nonlinear two-atom Tavis-Cummings models

We derive an analytical approximate solution of the time-dependent state vector in terms of material Bell states and coherent states of the field for a generalized two-atom Tavis-Cummings model with nonlinear intensity-dependent matter-field interaction. Using this solution, we obtain simple expressions for the atomic concurrence and purity in order to study the entanglement in the system at specific interaction times. We show how to implement entangling atomic operations through measurement of the field. We illustrate how these operations can lead to a complete Bell measurement. Furthermore, when considering two orthogonal states of the field as levels of a third qubit, it is possible to implement a unitary three-qubit gate capable of generating authentic tripartite entangled states such as the Greenberger-Horne-Zeilinger state and the W state. As an example of the generic model, we present an ion-trap setting employing the quantized mode of the center-of-mass motion instead of the photonic field, showing that the implementation of realistic entangling operations from intrinsic nonlinear matter-field interactions is indeed possible.

Automated summary

An analytical approximate solution was derived for a generalized two-atom Tavis-Cummings model with nonlinear intensity-dependent matter-field interaction, allowing for the study of entanglement in the system and implementation of entangling atomic operations through field measurement. The model also demonstrated the possibility of generating authentic tripartite entangled states using a unitary three-qubit gate.