Quantum many-body theory for qubit decoherence in a finite-size spin bath
- Department of Physics, Chinese University of Hong Kong, Shatin, N. T., Hong Kong (China)
We develop a cluster-correlation expansion theory for the many-body dynamics of a finite-size spin bath in a time scale relevant to the decoherence of a center spin or qubit embedded in the bath. By introducing the cluster correlation as the evolution of a group of bath spins divided by the correlations of all the subgroups, the propagator of the whole bath is factorized into the product of all possible cluster correlations. Each cluster-correlation term accounts for the authentic (non-factorizable) collective excitations within that group. Convergent results can be obtained by truncating the cluster-correlation expansion up to a certain cluster size, as verified in an exactly solvable spin-chain model.
- OSTI ID:
- 21254863
- Journal Information:
- AIP Conference Proceedings, Vol. 1074, Issue 1; Conference: 2. international workshop on solid-state quantum computing and mini-school on quantum information science, Taipei, Taiwan (China), 23-27 Jun 2008; Other Information: DOI: 10.1063/1.3037140; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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