2008/06/30 by Robert S. Whitney
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum and electron transport phenomena #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physreva.81.032108
published as Phys. Rev. A 81, 032108 (2010) · 14 pages - v4 Extended and improved presentation (complete change of method and results w.r.t. version 1)
arxiv created 2009/10/12 · openalex publication_date 2010/03/08 · arxiv updated 2010/04/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We consider a two-level system coupled to a highly non-Markovian environment when the coupling axis rotates with time. The environment may be quantum (for example a bosonic bath or a spin bath) or classical (such as classical noise). We show that an Anderson orthogonality catastrophe suppresses transitions, so that the system's instantaneous eigenstates (parallel and antiparallel to the coupling axis) can adiabatically follow the rotation. These states thereby acquire Berry phases; geometric phases given by the area enclosed by the coupling axis. Unlike in earlier proposals for environment-induced Berry phases, here there is little decoherence, so one does not need a decoherence-free subspace. Indeed we show that this Berry phase should be much easier to observe than a conventional one because it is not masked by either the dynamic phase or the leading nonadiabatic phase. The effects that we discuss should be observable in any qubit device where one can drive three parameters in the Hamiltonian with strong man-made noise.