Quantum macroscopic motions are investigated in the scheme consisting of N-number of harmonic oscillators in terms of ultra-power representations of nonstandard analysis. Decoherence is derived from the large internal degrees of freedom of macroscopic matters.
A decoherence mechanism in the transition from pure quantum- mechanical systems to thermodynamical systems is proposed. We see that a quantum-mechanical expression of temperature is derived and the expression for boson systems and that for fermion systems are different. An application to the calculation of change of temperatures is investigated in a quasi-static process and numerical analyses for mixing of two gases with different temperatures are carried out. Considerations in terms of ultra-power representations of nonstandard-analysis are also presented.
We revisit the quantum decoherence problem of the center of mass motion of a macroscopic object, which is modelled as a one-dimensional atom chain. Induced by the coupling of the center of mass (C.M) motion with the inner degrees of freedom, this inner-environment-induced decoherence is reflected by the localization of the C.M wave packet. We show that, the C.M motion is coupled to the inner states only when the chain has interaction with the external potential. This result provides a realistic mechanism for the analysis of the inner-environment-induced localization of a macroscopic object.