A phase operator formalism is presented within the framework of thermo field dynamics (TFD). It is shown that a unitary phase operator (or phase factor) can be defined as a canonical conjugate of the generator of phase shift in TFD since the generator has a lower bounded spectrum. The tilde...

The quantum dissipative dynamics of a phase variable is studied. A phase variable is treated as a quantum mechanical operator in Liouville space. The time translation properties of a phase operator and its eigenstate are investigated in terms of a time-evolution generator describing the phase...

A solvable model of quantum-statistical mechanical frequency modulation is proposed and is solved for the cases of boson and two-state irrelevant subsystems to obtain the intensity distribution for a certain operator of the relevant subsystem. The damping theoretical approach, which is based on...

Within the formalism of non-equilibrium thermo field dynamics (NETFD), a derivation of basic equations is given in their most general and suitable forms to take into account the coarse graining in the kinetic region and in the fluid mechanical region. A new concept, called the connection of...

The framework of multifractal analysis (MFA) is distilled to the most sophisticated one. Within this transparent framework, it is shown that the harmonious representation of MFA utilizing two distinct Tsallis distribution functions, one for the tail part of probability density function (PDF) and...

Degenerate parametric amplification accompanied by dissipation is analyzed within the canonical operator formalism for quantum dissipative systems named non-equilibrium thermo field dynamics. The vacuum of the system is subject to both dissipation and breaking of phase symmetry due to squeezing....

The effects of the interaction between atoms and a laser field on the damping phenomena of the laser system are examined by the perturbational treatment of the rigorous damping theory. Correction terms to the conventional master equation of the laser system are obtained and those to the...

The transient behavior of laser radiation from the unstable state (i.e., no photon at the initial time) is treated by the WKB treatment proposed by Caroli et al., and comparison of the results with those of the scaling theory is given. A simple approximation, needed for the WKB treatment to...

The damping theory is correctly applied to the coupled systems in contact with respective reservoirs. Differences between the present rigorous treatment of the damping theory and the conventional one are explicitly shown for an exactly solvable model of the parametric amplifier. The deviation...

The general scaling theory of transient phenomena near the instability point proposed by one of the authors (M.S.) is applied to analyze the transient behavior of laser radiation from the unstable state (i.e., no photon at the initial time). The analytic results thus obtained by the scaling...