Symmetrizing evolutions

✍ Scribed by Paolo Zanardi

• Book ID: 104337538
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 78 KB
• Volume: 258
• Category: Article
• ISSN: 0375-9601
• DOI: 10.1016/s0375-9601(99)00365-5

✦ Synopsis

We introduce quantum procedures for making G G-invariant the dynamics of an arbitrary quantum system S, where G G 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 G G 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.