From classical mechanics with doubled degrees of freedom to quantum field theory for nonconservative systems

Y. Kuwahara, Y. Nakamura, Y. Yamanaka

Research output: Contribution to journalArticle

5 Citations (Scopus)


The 2×2-matrix structure of Green's functions is a common feature for the real-time formalisms of quantum field theory under thermal situations, such as the closed time path formalism and Thermo Field Dynamics (TFD). It has been believed to originate from quantum nature. Recently, Galley has proposed the Hamilton's principle with initial data for nonconservative classical systems, doubling each degree of freedom [1]. We show that the Galley's Hamilton formalism can be extended to quantum field and that the resulting theory is naturally identical with nonequilibrium TFD.

Original languageEnglish
Pages (from-to)3102-3105
Number of pages4
JournalPhysics Letters, Section A: General, Atomic and Solid State Physics
Issue number43
Publication statusPublished - 2013 Dec 9



  • Canonical quantization
  • Nonconservative system
  • Nonequilibrium
  • Quantum field theory
  • Reservoir model
  • Thermo Field Dynamics

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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