46 research outputs found
Creating Metastable Schrodinger Cat States
We propose a scheme using feedback to generate a macroscopic quantum superposition of coherent states in an optical cavity mode which experiences very little decoherence (due to dissipation)
Decoherence, Re-coherence, and the Black Hole Information Paradox
We analyze a system consisting of an oscillator coupled to a field. With the
field traced out as an environment, the oscillator loses coherence on a very
short {\it decoherence timescale}; but, on a much longer {\it relaxation
timescale}, predictably evolves into a unique, pure (ground) state. This
example of {\it re-coherence} has interesting implications both for the
interpretation of quantum theory and for the loss of information during black
hole evaporation. We examine these implications by investigating the
intermediate and final states of the quantum field, treated as an open system
coupled to an unobserved oscillator.Comment: 23 pages, 2 figures included, figures 3.1 - 3.3 available at
http://qso.lanl.gov/papers/Papers.htm
Ponderomotive Control of Quantum Macroscopic Coherence
It is shown that because of the radiation pressure a Schr\"odinger cat state
can be generated in a resonator with oscillating wall. The optomechanical
control of quantum macroscopic coherence and its detection is taken into
account introducing new cat states. The effects due to the environmental
couplings with this nonlinear system are considered developing an operator
perturbation procedure to solve the master equation for the field mode density
operator.Comment: Latex,22 pages,accepted by Phys.Rev.
Classical and Quantum Signatures of Competing Chi(2) Nonlinearities
We report the first observation of the quantum effects of competing nonlinearities. We also report new classical signatures of competition, namely clamping of the second harmonic power and production of nondegenerate frequencies in the visible. Theory is presented that describes the observations as resulting from competition between various upconversion and downconversion processes. We show that competition imposes hitherto unsuspected limits to both power generation and squeezing. The observed signatures are expected to be significant effects in practical systems