  In the present study, we propose a new perspective on thermal dissipation
based on the thermo field dynamics. From the view point of the renormalization
theory, there appear effective interactions between the original and tilde
spaces on thermo field dynamics with reducing thermal disturbances. This study
yields the equivalence of the following two pictures, namely such a spin system
with a random field due to a heat bath as is defined in a Hilbert space and a
finite-size system with effective interactions defined in a double Hilbert
space. The correspondence of the above two systems yields such perspective that
the thermal disturbance is described by the effective non-Hermitian
interactions.
