Pure dephasing is a genuine quantum kinetic process resulting in a nonexponential decay of optical signals with an unusual nonmonotonous temperature dependence of the decay time. The coherent controllability of the initial decoherence is demonstrated.
We discuss the Rabi splitting and Rabi oscillation of excitons in semiconductor quantum dots and clarify the fundamental physics and new characteristic features. These coherent optical phenomena are not restricted to semiconductor quantum dots and the predicted features would be observed also in atoms and molecules. The universality of the phenomena ensures the possibility for application to quantum state control and quantum information processing by optical means. We discuss briefly the mechanisms of exciton dephasing in semiconductor quantum dots in conjunction with recent observations of the lifetime-limited exciton dephasing time and show that the pure dephasing rate is very small but is not vanishing even at zero Kelvin.
This work investigates the impact of decoherence induced by pure dephasing and phonon-assisted tunneling mechanisms on the optical and quantum properties of two quantum dots. Special attention is given to the density matrix at steady state, and a detailed analysis of populations, coherences, optical transitions and the emission spectrum is performed. Additionally, we study the influence of both phonon-decoherence mechanisms on bipartite entanglement and the degree of mixedness of the system. In particular, our findings indicate that the phonon-assisted tunneling mechanism partially affects the coherences of the system and quantum properties when the imbalance of phonon absorption and emission is significant. Conversely, the pure dephasing mechanism does not affect the populations but strongly entangles the quantum dots and the reservoir, inducing maximally mixed states and significantly reducing the spectral splitting in the emission spectrum of the system.