Analytical solution of the quantum-state tomography of the biexciton cascade in semiconductor quantum dots: Pure dephasing does not affect entanglement

Abstract

A fundamental approach to generate polarization-entangled photon pairs from solid-state devices is the biexciton cascade in semiconductor quantum dots. For efficient photon pair generation in the weak coupling regime, we present an analytical solution for the two-photon matrix elements (quantum-state tomography), including dephasing and relaxation mechanisms. In particular, we show that a pure dephasing mechanism does not affect the degree of entanglement for quantum dots with degenerated exciton levels.