Symmetrizing evolutions
Sep, 1998Citations per year
Abstract:
We introduce quantum procedures for making -invariant the dynamics of an arbitrary quantum system S, where is a finite group acting on the space state of S. Several applications of this idea are discussed. In particular when S is a N-qubit quantum computer interacting with its environment and the symmetric group of qubit permutations, the resulting effective dynamics admits noiseless subspaces. Moreover it is shown that the recently introduced iterated-pulses schemes for reducing decoherence in quantum computers fit in this general framework. The noise-inducing component of the Hamiltonian is filtered out by the symmetrization procedure just due to its transformation properties.Note:
- Presentation improved, to appear in Phys. Lett. A. 5 pages LaTeX, no figures
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