Transport-Induced Decoherence of the Entangled Triplet Exciton Pair

Decoherence effects for entangled triplet pairs in organic molecular crystals are analyzed for the case when excitons can hop between inequivalent lattice sites. The fluorescence quantum beats caused by quantum interference upon triplet-triplet recombination into an emissive singlet state are predicted as a function of hopping time and magnetic field based on a Monte Carlo analysis. Depending on exciton hopping rates, it is possible to have complete global decoherence and suppression of fluorescence quantum beats in the limit of zero magnetic field, and to have quantum beats that decay at different rates depending on magnetic field strength.