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A quantum dissipation theory is constructed with the system-bath interaction being treated rigorously at the second-order cumulant level for both reduced dynamics and initial canonical boundary condition. The theory is valid for arbitrary bath correlation functions and time-dependent external driving fields, and satisfies correlated detailed-balance relation at any temperatures. The general formulation assumes a particularly simple form in driven Brownian oscillator systems in which the correlated driving-dissipation effects can be accounted for exactly in terms of local-field correction. Remarks on a class of widely used phenomenological quantum master equations that neglects the bath dispersion-induced dissipation are also made in contact with the present theory. [ABSTRACT FROM AUTHOR]

By using a rather simple algebraic approach, we revisit and further bridge between two most commonly used quantum dissipation theories, the Bloch-Redfield theory and a class of Fokker-Planck equations. The nature of the common approximation scheme involving in these two theories is analyzed in detail. While the Bloch-Redfield theory satisfies the detailed-balance relation, we also construct a class of Fokker-Planck equations that satisfy the detailed-balance relation up to the second moments in phase-space. Developed is also a generalized Fokker-Planck equation that preserves the general positivity of the reduced density operator. Both T[sub 1]-relaxation and pure-T[sub 2] dephasing are considered, and their temperature dependence is shown to be very different. Provided is also an analogy between the quantum pure-T[sub 2] dephasing and the classical heat transport. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A non-Markovian theory of dissipative many-electron systems in the presence of arbitrary coherent fields is presented. The new formulation is constructed via the second-quantization of a complete second-order quantum dissipation theory followed by the random phase or time-dependent Hartree–Fock approximation for electron–electron correlation. The theory is shown to be of the Fermi–Dirac thermal equilibrium statistics limit if electron–electron correlation is neglected. The key quantity is the reduced single-electron density matrix instead of the reduced density matrix of the system, which leads to the drastic reduction of numerical simulation time. The validity of the dynamic mean-field approximation is tested in a model two-electron spin-conversed system with Ohmic dissipation in the presence of excitation field. [Copyright &y& Elsevier]