%0 Journal Article
%T Quantum Tricritical Point in the Spin-Boson Model with an Ohmic Bath
%A CHEN Wen
%A CHEN Zhi-De
%A <br>陈文
%A 陈芝得
%J 中国物理快报
%D 2007
%I 
%X The dynamics of the spin-boson model with an Ohmic bath at finite temperature is studied by a variational calculation. Numerical solution of the self-consistent equation derived from the variational method shows that the transition from incoherent to coherent phases is discontinuous. It indicates that （T = 0, s = 1） is a tricritical point, i.e. the transition changes from continuous to discontinuous by tuning from T = 0 to T≠ 0. The discontinuous transition at finite temperature is analysed by Landau theory and the relation to the experimental observation on the coherent state is also discussed.
%K 03
%K 65
%K Yz
%K 03
%K 65
%K Xp
%K 73
%K 40
%K Gk<br>自旋玻色子模型
%K 量子
%K 温度
%K 自调和方程
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=E27DA92E19FE279A273627875A70D74D&aid=A6F1F92187EC7BB8A9264E25A65C188D&yid=A732AF04DDA03BB3&vid=B91E8C6D6FE990DB&iid=94C357A881DFC066&sid=D932AD0F8FDA3032&eid=CF89D3C02791C82E&journal_id=0256-307X&journal_name=中国物理快报&referenced_num=0&reference_num=0