Non-Markovian decoherence theory for a double-dot charge qubit
- Department of Physics and Center for Quantum Information Science, National Cheng Kung University, Tainan 70101, Taiwan (China)
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 T{sub 1} and dephasing time T{sub 2} are analyzed in detail.
- OSTI ID:
- 21192507
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 78, Issue 23; Other Information: DOI: 10.1103/PhysRevB.78.235311; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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