Linear response in non-equilibrium thermo field dynamics

K. Nakamura*, Y. Yamanaka, H. Umezawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


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.

Original languageEnglish
Pages (from-to)29-50
Number of pages22
JournalPhysica A: Statistical Mechanics and its Applications
Issue number1-2
Publication statusPublished - 1988 Sept
Externally publishedYes

ASJC Scopus subject areas

  • Statistics and Probability
  • Condensed Matter Physics


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