325 research outputs found
Involutive constrained systems and Hamilton-Jacobi formalism
In this paper, we study singular systems with complete sets of involutive
constraints. The aim is to establish, within the Hamilton-Jacobi theory, the
relationship between the Frobenius' theorem, the infinitesimal canonical
transformations generated by constraints in involution with the Poisson
brackets, and the lagrangian point (gauge) transformations of physical systems
Hysteretic nonequilibrium Ising-Bloch transition
We show that a parametrically driven cubic-quintic complex Ginzburg-Landau
equation exhibits a hysteretic nonequilibrium Ising-Bloch transition for large
enough quintic nonlinearity. These results help to understand the recent
experimental observation of this pheomenon [A. Esteban-Martin et al., Phys.
Rev. Lett. 94, 223903 (2005)].Comment: 3 pages + six figure
Phase-locking of a Nonlinear Optical Cavity via Rocking: Transmuting Vortices into Phase Patterns
We report experimental observation of the conversion of a phase-invariant
nonlinear system into a phase-locked one via the mechanism of rocking [G. J. de
Valcarcel and K. Staliunas, Phys. Rev. E 67, 026604 (2003)]. This conversion
results in that vortices of the phase-invariant system are being replaced by
phase patterns such as domain walls. The experiment is carried out on a
photorefractive oscillator in two-wave mixing configuration.A model for the
experimental device is given that reproduces the observed behavior.Comment: 9 pages and 4 figure
Hamilton-Jacobi formalism for Linearized Gravity
In this work we study the theory of linearized gravity via the
Hamilton-Jacobi formalism. We make a brief review of this theory and its
Lagrangian description, as well as a review of the Hamilton-Jacobi approach for
singular systems. Then we apply this formalism to analyze the constraint
structure of the linearized gravity in instant and front-form dynamics.Comment: To be published in Classical and Quantum Gravit
Quantum correlations and fluctuations in the pulsed light produced by a synchronously pumped optical parametric oscillator below its oscillation threshold
We present a simple quantum theory for the pulsed light generated by a
synchronously pumped optical parametric oscillator (SPOPO) in the degenerate
case where the signal and idler trains of pulses coincide, below threshold and
neglecting all dispersion effects. Our main goal is to precise in the obtained
quantum effects, which ones are identical to the c.w. case and which ones are
specific to the SPOPO. We demonstrate in particular that the temporal
correlations have interesting peculiarities: the quantum fluctuations at
different times within the same pulse turn out to be totally not correlated,
whereas they are correlated between nearby pulses at times that are placed in
the same position relative to the centre of the pulses. The number of
significantly correlated pulses is of the order of cavity finesse. We show also
that there is perfect squeezing at noise frequencies multiple of the pulse
repetition frequency when one approaches the threshold from below on the signal
field quadrature measured by a balanced homodyne detection with a local
oscillator of very short duration compared to the SPOPO pulse length.Comment: 12 pages, 3 figure
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