Non-Markovian decoherence theory for a double-dot charge qubit

Matisse W.Y. Tu, Wei Min Zhang

Research output: Contribution to journalArticlepeer-review

145 Citations (Scopus)

Abstract

In this paper, we develop a nonperturbation theory for describing decoherence dynamics of electron charges in a double quantum dot gated by electrodes. We extend the Feynman-Vernon influence functional theory to fermionic environments and derive an exact master equation for the reduced density matrix of electrons in the double dot for a general spectral density at arbitrary temperature and bias. We then investigate the decoherence dynamics of the double-dot charge qubit with backreaction of the reservoirs being fully taken into account. Time-dependent fluctuations and leakage effects induced from the dot-reservoir coupling are explicitly explored. The charge qubit dynamics from the Markovian to non-Markovian regime is systematically studied under various manipulating conditions. The decay behavior of charge qubit coherence and the corresponding relaxation time T1 and dephasing time T 2 are analyzed in detail.

Original languageEnglish
Article number235311
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume78
Issue number23
DOIs
Publication statusPublished - 2008 Dec 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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