General quantum mechanical theory of pure dephasing

Makoto Yamaguchi, Alexey Lyasota, Tatsuro Yuge

We propose a Markovian quantum master equation that can describe the Fano effect directly, by assuming a standard cavity quantum electrodynamics system.The framework allows us to generalize the Fano formula, applicable over the weak-and strong-coupling regimes with pure dephasing.A formulation of its emission spectrum is also given in a consistent manner.We then find that the interference responsible for the Fano effect is robust against pure dephasing.This is counterintuitive because the impact of interference is, in general, severely reduced by decoherence processes.Our approach thus provides a basis for theoretical treatments of the Fano effect and insights into the quantum interference in open quantum systems.

Mikio Namiki, Hiromichi Nakazato, Saverio Pascazio

Shuang Xu, Wei‐Jiang Gong, H. Z. Shen +1 more

It has been well established that the evolution of an isolated quantum system can appear as undergoing pure dephasing to an observer using an imperfect clock. In this work, we apply this theory to the transport phenomenon in open quantum systems. Starting with a system intrinsically undergoing nonunitary evolution in ideal time, we consider the effect of a realistic clock that approaches Gaussian distribution in the long-time limit. For quantum transport, it eventually leads to a general physical prediction: a stable probability current in a quantum transport system must be robust against any transformation that conforms with a simple formula given by an ideal Gaussian stationary clock. This understanding of quantum transport is demonstrated numerically in a topological insulator, where it also explains the robustness of the quantum Hall response against pure dephasing.

Jürgen Brickmann, Peter Russegger

Masahiro Abe, Masashi Ban

Xiaoming Li, Tao Wang, Chuanbo Dong

Population decay (real transition) and pure dephasing (virtual transition) determine the dephasing rates of excitons in quantum-dot (QD) semiconductor optical amplifiers. In previous theoretical studies, population-decay and pure dephasing are usually handled separately. In this paper, the theory of exciton dephasing in an InAs/GaAs QD semiconductor optical amplifier is presented to elucidate the combination of population decay and pure dephasing and determine the total dephasing rate. The proposed model extends the classical independent boson model to include the effects of real transition. Results show that population decay decreases the pure dephasing rate and imply that the former is directly coupled to pure dephasing despite their differences. Our theoretical results are consistent with the reported experimental phenomena.