  A wide variety of dissipative and fluctuation problems involving a quantum
system in a heat bath can be described by the independent-oscillator (IO) model
Hamiltonian. Using Heisenberg equations of motion, this leads to a generalized
quantum Langevin equation (QLE) for the quantum system involving two quantities
which encapsulate the properties of the heat bath. Applications include: atomic
energy shifts in a blackbody radiation heat bath; solution of the problem of
runaway solutions in QED; electrical circuits (resistively shunted Josephson
barrier, microscopic tunnel junction, etc.); conductivity calculations (since
the QLE gives a natural separation between dissipative and fluctuation forces);
dissipative quantum tunneling; noise effects in gravitational wave detectors;
anomalous diffusion; strongly driven quantum systems; decoherence phenomena;
analysis of Unruh radiation and entropy for a dissipative system.
