Polarization-entangled photon generation by a semiconductor quantum dot   coupled to a cavity interacting with external fields
  We theoretically investigate polarization-entangled photon generation by using a semiconductor quantum dot embedded in a microcavity. The entangled states can be produced by the application of two cross-circularly polarized laser fields. The quantum dot nanostructure is considered as a four-level system (ground, two excitons and bi-exciton states) and the theoretical study relies on the dressed states scheme. The quantum correlations, reported in terms of the entanglement of formation, are extensively studied for several values of the important parameters of the quantum dot system as the bi-exciton binding energy, {the decoherence times of the characteristic transitions, the quality factor of the cavity} and the intensities of the applied fields. 
Kostas Blekos and Nikos Iliopoulos and Maria-Eftaksia Stasinou and   Evaggelos Vlachos and Andreas F. Terzis
quant-ph