145 research outputs found
Modified Bloch equations in presence of a nonstationary bath
Based on the system-reservoir description we propose a simple solvable
microscopic model for a nonequilibrium bath. This captures the essential
features of a nonstationary quantum Markov process. We establish an appropriate
generalization of the fluctuation-dissipation relation pertaining to this
process and explore the essential modifications of the Bloch equations to
reveal the nonexponential decay of the Bloch vector components and transient
spectral broadening in resonance fluorescence. We discuss a simple experimental
scheme to verify the theoretical results.Comment: Revtex, 27 pages, 2 ps figures. To appear in European Physical
Journal
Quantum noise-induced chaotic oscillations
We examine the weak quantum noise limit of Wigner equation for phase space
distribution functions. It has been shown that the leading order quantum noise
described in terms of an auxiliary Hamiltonian manifests itself as an
additional fluctuational degree of freedom which may induce chaotic and regular
oscillations in a nonlinear oscillator.Comment: minor corrections, new references adde
Adiabatic noise-induced escape rate for nonequilibrium open systems
We consider the motion of an overdamped particle in a force field in presence
of an external, adiabatic noise, without the restriction that the noise process
is Gaussian or the stochastic process is Markovian. We examine the condition
for attainment of steady state for this nonequilibrium open system and
calculate the adiabatic noise-induced rate of escape of the particle over a
barrier.Comment: 6 pages, 3 figure
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