Dynamic structure function of a cold Fermi gas at unitarity

17th International Conference on Recent Progress in Many-Body Theories

Astrakharchik, G.E.^1 ; Boronat, J.^1 ; Krotscheck, E.^2,3 ; Lichtenegger, T.^2,3

Departament de Física i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politècnica de Catalunya, E-08034 Barcelona, Spain^1

Department of Physics, University at Buffalo, SUNY, Buffalo NY 14260, United States^2

Institut für Theoretische Physik, Johannes Kepler Universität, A 4040 Linz, Austria^3

关键词: Bragg scattering;    Dynamic structure;    Excitation theory;    Fixed node diffusion monte carlo;    Ground-state correlation;    Theoretical study;    Two-component fermi gas;    Zero temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/529/1/012009/pdf
DOI  :  10.1088/1742-6596/529/1/012009

来源: IOP

【 摘 要 】

We present a theoretical study of the dynamic structure function of a resonantly interacting two-component Fermi gas at zero temperature. Our approach is based on dynamic many-body theory able to describe excitations in strongly correlated Fermi systems. The fixed-node diffusion Monte Carlo method is used to produce the ground-state correlation functions which are used as an input for the excitation theory. Our approach reproduces recent Bragg scattering data in both the density and the spin channel. In the BCS regime, the response is close to that of the ideal Fermi gas. On the BEC side, the Bose peak associated with the formation of dimers dominates the density channel of the dynamic response. When the fraction of dimers is large our theory departs from the experimental data, mainly in the spin channel.