Café com Física



04 de maio de 2016

Prof. Analabha Roy
National Institute for Theoretical Physics, Stellenbosch, South Africa

Simulation of Quantum Spin Dynamics by Phase Space Sampling of BBGKY

Recent experimental developments in quantum simulators with lattice spins in ion traps have necessitated the search for numerical techniques that adequately describe their dynamics. While methods based on matrix product states have been successful with one-dimensional systems up to intermediate time-scales, computational methods of equivalent accuracy for larger dimensions remain elusive. I will present a novel method that is suitable for simulating the dynamics of quantum spin models of any dimension. The method samples the many body Wigner function and evaluates the evolution equations obtained from the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy. Higher orders in the hierarchy allow for systematic refinements. Quantum correlations can be treated through both, the Wigner function sampling and the BBGKY evolution, bringing about highly accurate estimates of correlations and entanglement witnesses.
The method is particularly suitable for nonintegrable systems, especially those with long-range interactions. I will demonstrate its efficacy by comparing with exact results, as well as other numerical methods. Finally, I conclude with outlooks into modelling the Lindblad dynamics of the collective scattering of classical light by cold quantum gases, especially phenomena like superradiance, as well as experimental corrections in lattice spin simulators due to decoherence.