106 research outputs found
A Model for Quantum Stochastic Absorption in Absorbing Disordered Media
Wave propagation in coherently absorbing disordered media is generally
modeled by adding a complex part to the real part of the potential. In such a
case, it is already understood that the complex potential plays a duel role; it
acts as an absorber as well as a reflector due to the mismatch of the phase of
the real and complex parts of the potential. Although this model gives expected
results for weakly absorbing disordered media, it gives unphysical results for
the strong absorption regime where it causes the system to behave like a
perfect reflector. To overcome this issue, we develop a model here using
stochastic absorption for the modeling of absorption by "fake", or "side",
channels obviating the need for a complex potential. This model of stochastic
absorption eliminates the reflection that is coupled with the absorption in the
complex potential model and absorption is proportional to the magnitude of the
absorbing parameter. Solving the statistics of the reflection coefficient and
its phase for both the models, we argue that stochastic absorption is a
potentially better way of modeling absorbing disordered media.Comment: 5 pages, 4 figure
Quantum correlations and classical resonances in an open chaotic system
We show that the autocorrelation of quantum spectra of an open chaotic system
is well described by the classical Ruelle-Pollicott resonances of the
associated chaotic strange repeller. This correspondence is demonstrated
utilizing microwave experiments on 2-D n-disk billiard geometries, by
determination of the wave-vector autocorrelation C(\kappa) from the
experimental quantum spectra S_{21}(k). The correspondence is also established
via "numerical experiments" that simulate S_{21}(k) and C(\kappa) using
periodic orbit calculations of the quantum and classical resonances.
Semiclassical arguments that relate quantum and classical correlation functions
in terms of fluctuations of the density of states and correlations of particle
density are also examined and support the experimental results. The results
establish a correspondence between quantum spectral correlations and classical
decay modes in an open systems.Comment: 10 pages, 5 eps figures, "Quantum chaos Y2K" Nobel symposium, to
appear in Physica Script
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