Presented in the 2023 SPP conference about the comparisson of the positive-P representation and truncated Wigner approximation for the Dicke model. Here are the details of the presentation.
Picture of the Theoretical Physics Group (all subgroup) of NIP
A comparison of Positive-P and truncated Wigner methods for the dynamics of a minimal atom-cavity model #
Richelle Jade L. Tuquero, and Jayson G. Cosme
Abstract
We investigate various phase-space methods for simulating the Dicke model. One such phase-space method is the positive-P representation. This method is implemented by transforming the Hamiltonian using the Schwinger boson representation. The resulting differential equations for the positive-P representation yield a nondiagonal diffusion matrix. Compared to dissipative discrete truncated Wigner method, the positive-P representation applied to the Dicke model produces divergent results, signalling the breakdown of the method, at relatively early times. Lastly, we compare the dynamics for collective and individual spins.
The paper can be accessed through this link: https://proceedings.spp-online.org/article/view/SPP-2023-3H-04