Distilling entanglement from random cascades with partial “which path” ambiguity
Eli A. Meirom, Netanel H. Lindner, Y. Berlatzky, Eilon Poem, Nika Akopian, J. E. Avron, D. Gershoni · Physical Review A · 2008
We develop a framework to calculate the density matrix of a pair of photons emitted in a decay cascade with partial ``which path'' ambiguity. We describe an appropriate entanglement distillation scheme which works also for certain random cascades. The qualitative features of the distilled entanglement are presented in a two dimensional ``phase diagram.'' The theory is applied to the quantum tomography of the decay cascade of a biexciton in a semiconductor quantum dot. Agreement with experiment is obtained.