%0 Journal Article
%T Annihilation operators associated with unstable vacua in non-equilibrium thermo-field dynamics
%A K. Yoshida
%A T. Arimitsu
%J Condensed Matter Physics
%D 2008
%I Institute for Condensed Matter Physics
%X Out of thermal equilibrium state, the vacuum is unstable and evolves in time. Consequently, the annihilation operators associated with the unstable vacuum depend on time. This dissipative time-evolution of quantum systems can be systematically treated, within the canonical operator formalism referred to as non-equilibrium thermo-field dynamics. Given is an alternative route to derive the time-dependent annihilation operators within the formalism. As an example, time-dependent annihilation operators for the systems of bosonic and fermionic semi-free fields are derived.
%K non-equilibrium thermo-field dynamics
%K annihilation operator
%K unstable vacuum
%K dissipative quantum systems
%K time-dependent Bogoliubov transformation
%U http://dx.doi.org/10.5488/CMP.11.4.687