Entanglement for excitons in two quantum dots in a cavity injected with squeezed vacuum

The dynamical behavior of entanglement for excitons in two quantum dots placed in a cavity driven by a broadband squeezed vacuum is studied in the low exciton density regime. It is found that the excitons in two quantum dots can evolve into a pure entangled state only when the dissipation of the cavity and exciton modes is negligible. When the injected field into the cavity is a squeezed vacuum, the excitons will be in a two-mode Gaussian entangled mixed state even in the long time limit. Analytical expressions are derived, showing the dependence of the entanglement property of the excitons in two quantum dots on the squeezing properties of the initial state prepared in the cavity and the strength of two-photon correlations of the squeezed vacuum injected into the cavity.