CFOP线性响应理论在费米性凝聚体中的应用

项目名称： CFOP线性响应理论在费米性凝聚体中的应用

项目编号： No.11204032

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 郭昊

作者单位： 东南大学

项目金额： 24万元

中文摘要： 本项目的研究对象集中在费米性量子简并气体，既包含了已经在国际上引起广泛兴趣多年的低能的非相对论性超冷原子气体，也包含了高能的相对论性凝聚体，如相对论性费米气体或者色超导（流）体等等。我们将特别关注目前受关注相对较少的相对论性凝聚体，并研究它的相关物性。我们工作的基础是对非相对论性和相对论性费米性凝聚体建立这样一套矩阵式线性响应理论(CFOP理论)，该理论自洽地考虑了序参量在外场影响下的涨落效应，从而真正"恢复"原本被费米子配对凝聚所破缺的U(1)规范对称性。该理论使得Nambu-Goldstone玻色子的效应被自然、正确地包含进来。该理论应用于非相对论性超冷原子气体时，已经获得很多很好的结果，如计算低温下幺正性超冷原子气体的切向粘滞系数，与实验吻合较好。我们预期在非相对论性的冷原子光学晶格和相对论性的费米凝聚体的物性研究中做出一些有意义的预言。

中文关键词： 线性响应；超冷原子气体；规范对称性；玻色爱因斯坦凝聚；

英文摘要： This project is focused on a class of fermionic quantum degenerate gases. It covers not only the non-relativistic ultra-cold atomic gases which has caught a wide interests over the world, but also the relativistic condensate, such as relativistic Fermi gases or color superconductivity. We will pay more attention to the latter since it catches relatively less concerns. The basis of our project is to build a matrix linear reponse theory for both non-relativistic and relativistic Fermi condensates, and this approach is based on consistent fluctuations of order parameter (CFOP). The U(1) symmetry which is broken by the pairing condensation is restored within this framework, and the effects of Nambu-Goldstone modes are natually included. We have obtained some good predictions when applying this theory to non-relativistic systems. Our calculation of the shear viscosity of unitary Fermi gases agrees well with some known experimental results. We expect it will also produce some interesting predictions in atomic systems in optical lattices and relativistic fermionic superfluids.

英文关键词： linear response；ultracold Fermi gas；gauge invariance；Bose-Einstein Condensation；