Thermal field theory using Thermo Field Dynamics (有限温度・有限密度の場の量子論とその応用)

An introduction to thermo field dynamics--equilibrium and non-equilibrium (including comparisons with other thermal theories)

Thermal degree of freedom in thermo field dynamics

Estimation of the thermal degree of freedom in thermo field dynamics

Dynamical rearrangement of the thermal vacuum in thermo field dynamics

A role of thermal state conditions in equilibrium and non-equilibrium thermo field dynamics

Thermo field dynamics-Thermal state condition and quantum algebra