Geometric decoherence in diffusive open quantum systems

Da Wei Luo, Hai Qing Lin, J. Q. You, Lian Ao Wu, Rupak Chatterjee, Ting Yu

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Based on a generic quantum open system model, we study the geometric nature of decoherence by defining a complex-valued geometric phase through stochastic pure states describing nonunitary, noncyclic, and nonadiabatic evolutions. The ensemble average of the complex geometric phases for the pure stochastic states yields a conventional geometric phase together with an amplitude factor. We show that the decoherence process described by the decaying amplitude can be a geometric quantity independent of the system's dynamics. It is a remarkable fact that the geometric phase of a quantum system can serve as an ideal realization of quantum gates due to its robustness against dynamical errors; however, in this paper we show that, for some open quantum systems, a desirable geometric phase may be accompanied by an unwanted robust geometric decoherence factor. Two exactly solvable models are studied to demonstrate that, while the decoherence is a purely dynamical effect for a dephasing two-level model, the decoherence in a dissipative two-level model can be a geometric process. Finally, we show that such a geometric decoherence effect may be eliminated by a nonperturbative control scheme.

Original languageEnglish
Article number062112
JournalPhysical Review A
Volume100
Issue number6
DOIs
StatePublished - 10 Dec 2019

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