5,243 research outputs found
Entropy production in open quantum systems: exactly solvable qubit models
We present analytical results for the time-dependent information entropy in
exactly solvable two-state (qubit) models. The first model describes dephasing
(decoherence) in a qubit coupled to a bath of harmonic oscillators. The entropy
production for this model in the regimes of "complete" and "incomplete"
decoherence is discussed. As another example, we consider the damped
Jaynes-Cummings model describing a spontaneous decay of a two-level system into
the field vacuum. It is shown that, for all strengths of coupling, the open
system passes through the mixed state with the maximum information entropy.Comment: 9 pages, 3 figure
Short time dynamics with initial correlations
The short-time dynamics of correlated systems is strongly influenced by
initial correlations giving rise to an additional collision integral in the
non-Markovian kinetic equation. Exact cancellation of the two integrals is
found if the initial state is thermal equilibrium which is an important
consistency criterion. Analytical results are given for the time evolution of
the correlation energy which are confirmed by comparisons with molecular
dynamics simulations (MD)
Surface EM waves on 1D Photonic Crystals
We study surface states of 1D photonic crystals using a semiclassical coupled
wave theory. Both TE and TM modes are treated. We derive analytic
approximations that clarify the systematics of the dispersion relations, and
the roles of the various parameters defining the crystal.Comment: 7 pages, 8 figure
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