%0 Journal Article
%T A Physical Explanation for Tilde System in Thermo Field Dynamics
%A Dong Mi
%A He-Shan Song
%A Ying An
%J Physics
%D 2001
%I arXiv
%R 10.1142/S0217732301003607
%X For a two-body quantum system, any pure state can be represented by a biorthogonal expression by means of Schmidt decomposition. Using this in the composite system which include a thermodynamic system and its surroundings, it is found that the tilde system in thermo field dynamics is just the surroundings of the real system.
%U http://arxiv.org/abs/quant-ph/0102127v2