title: Efficient scheme for numerical simulations of the spin-bath decoherence.
abstract: We demonstrate that the Chebyshev expansion method is a very efficient numerical tool for studying spin-bath decoherence of quantum systems. We consider two typical problems arising in studying decoherence of quantum systems consisting of a few coupled spins: (i) determining the pointer states of the system and (ii) determining the temporal decay of quantum oscillations. As our results demonstrate, for determining the pointer states, the Chebyshev-based scheme is at least a factor of 8 faster than existing algorithms based on the Suzuki-Trotter decomposition. For problems of the second type, the Chebyshev-based approach is 3-4 times faster than the Suzuki-Trotter-based schemes. This conclusion holds qualitatively for a wide spectrum of systems, with different spin baths and different Hamiltonians.
authors.affiliation: Ames Laboratory, Iowa State University, Ames, IA 50011, USA.
authors.forename: V V
authors.initials: VV
authors.lastname: Dobrovitski
authors.forename: H A
authors.initials: HA
authors.lastname: De Raedt