The linear response theory is discussed in the context of non-equilibrium thermo field dynamics which has been developed in recent years and can deal with a quantum field system in time-dependent non-equilibrium situations. An example of a simple model is given to illustrate the present formalism. Emphasis is put on the fact that in non-equilibrium thermo field dynamics the change of a thermal situation due to an external source should appear through the thermal Bogoliubov transformation, creating a new contribution to the linear response formula. It is also found that the dissipativity naturally comes out in the conventional retarded correlation.
|Number of pages||22|
|Journal||Physica A: Statistical Mechanics and its Applications|
|Publication status||Published - 1988|
ASJC Scopus subject areas
- Mathematical Physics
- Statistical and Nonlinear Physics