13,818 research outputs found
The photon blockade effect in optomechanical systems
We analyze the photon statistics of a weakly driven optomechanical system and
discuss the effect of photon blockade under single photon strong coupling
conditions. We present an intuitive interpretation of this effect in terms of
displaced oscillator states and derive analytic expressions for the cavity
excitation spectrum and the two photon correlation function . Our
results predict the appearance of non-classical photon correlations in the
combined strong coupling and sideband resolved regime, and provide a first
detailed understanding of photon-photon interactions in strong coupling
optomechanics
Dynamical Stability and Quantum Chaos of Ions in a Linear Trap
The realization of a paradigm chaotic system, namely the harmonically driven
oscillator, in the quantum domain using cold trapped ions driven by lasers is
theoretically investigated. The simplest characteristics of regular and chaotic
dynamics are calculated. The possibilities of experimental realization are
discussed.Comment: 24 pages, 17 figures, submitted to Phys. Rev
A Bell pair in a generic random matrix environment
Two non-interacting qubits are coupled to an environment. Both coupling and
environment are represented by random matrix ensembles. The initial state of
the pair is a Bell state, though we also consider arbitrary pure states.
Decoherence of the pair is evaluated analytically in terms of purity; Monte
Carlo calculations confirm these results and also yield the concurrence of the
pair. Entanglement within the pair accelerates decoherence. Numerics display
the relation between concurrence and purity known for Werner states, allowing
us to give a formula for concurrence decay.Comment: 4 pages, 3 figure
International Control of the Safety of Nuclear-Powered Merchant Ships
In recent years we have witnessed the transition of nuclear-powered ships from an imaginative dream to an engineering reality. This vast step from the drawing board to successful operation on the high-seas has taken place in a remarkably short span of time. Nevertheless, in the :flush of enthusiasm over the technological achievement, we must not lose sight of the fact that the promise of nuclear power for the propulsion of ships will not have been fulfilled until nuclear vessels are operating safely and economically over the maritime trade routes of the world. It would be unrealistic to assume that further progress, from military and demonstration vessels subsidized by governments, to commercially competitive merchantmen, will not be more difficult, more time-consuming, and more taxing to our ingenuity than the steps taken thus far
An M-theory solution generating technique and SL(2,R)
In this paper we generalize the O(p+1,p+1) solution generating technique
(this is a method used to deform Dp-branes by turning on a NS-NS B-field) to
M-theory, in order to be able to deform M5-brane supergravity solutions
directly in eleven dimensions, by turning on a non zero three form A. We find
that deforming the M5-brane, in some cases, corresponds to performing certain
SL(2,R) transformations of the Kahler structure parameter for the three-torus,
on which the M5-brane has been compactified. We show that this new M-theory
solution generating technique can be reduced to the O(p+1,p+1) solution
generating technique with p=4. Further, we find that it implies that the open
membrane metric and generalized noncommutativity parameter are manifestly
deformation independent for electric and light-like deformations. We also
generalize the O(p+1,p+1) method to the type IIA/B NS5-brane in order to be
able to deform NS5-branes with RR three and two forms, respectively. In the
type IIA case we use the newly obtained solution generating technique and
deformation independence to derive a covariant expression for an open D2-brane
coupling, relevant for OD2-theory.Comment: 24 pages, Latex. v2:Sections 3.2 and 3.3 improved. v3:Some
clarifications added. Version published in JHE
Hamilton-Jacobi Formulation of KS Entropy for Classical and Quantum Dynamics
A Hamilton-Jacobi formulation of the Lyapunov spectrum and KS entropy is
developed. It is numerically efficient and reveals a close relation between the
KS invariant and the classical action. This formulation is extended to the
quantum domain using the Madelung-Bohm orbits associated with the Schroedinger
equation. The resulting quantum KS invariant for a given orbit equals the mean
decay rate of the probability density along the orbit, while its ensemble
average measures the mean growth rate of configuration-space information for
the quantum system.Comment: preprint, 8 pages (revtex
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