1,721,010 research outputs found
HAMILTONIAN DESCRIPTION OF NONLINEAR PROPAGATION IN OPTICAL FIBERS
No full textNonlinear propagation in single-mode and multimode fibers in the presence of the optical Kerr effect is described in terms of a number of parameters (four for each propagating mode) which can be interpreted as conjugate variables of a suitable Hamiltonian system. The formal simplicity of this approach, which admittedly furnishes a limited description of nonlinear propagation because of the finiteness of the number of variables employed, is, however, very useful for gaining a straightforward physical insight into the problem. The solution of the pertinent equations, either analytical or numerical, presents a much less formidable task than the solution of the set of nonlinear equations fully describing propagation. © 1988 The American Physical Society
Novel optical phenomena in near-critical photorefractive crystals: diffusion-driven diffraction and spontaneous self-trapping
No full textWe investigate nonlinear optical diffraction in a photorefractive paraelectric, heated slightly above the ferroelectric phase transition. Theoretically, the basic photorefractive band-transport model leads to an anisotropic, nonlinear and nonlocal propagation equation that remarkably allows for explicit analytical solutions, in the form of anisotropic diffraction and noncircular solitons without characteristic length scale. Experiments qualitatively support predictions, but suggest that spontaneous crystal response is present. Actual spontaneous domain formation is experimentally seen to lead to optical self-trapping in both one and two transverse spatial dimensions
Scheme for total quantum teleportation
No full textWe address the issue of totally teleporting the quantum stare of an external particle, as opposed to studies on partial teleportation of external single-panicle states, total teleportation of coherent states and encoded single-particle states, and intramolecular teleportation of nuclear spin states. We find a set of commuting observables whose measurement directly projects onto the Bell basis and discuss a possible experiment, based on two-photon absorption, allowing, for the first time, total teleportation of the state of a single external photon through a direct projective measurement
Bell states, Bell operators, and total teleportation
No full textWe identify the operators and the corresponding physical quantities whose measurement allows in principle to obtain total teleportation of the unknown spin state of a single electron. We introduce an analogous scheme for a single photon and discuss its experimental implementation
Nonlinear optical propagation in near-transition centrosymmetric photorefractive crystals
No full textWe relate on a series of optical nonlinear propagation phenomena, mediated by photorefraction, present in ferroelectric crystals heated above the Curie point, in proximity of the critical regime. In particular, we discuss centrosymmetric screening solitons, diffusion-driven anisotropic nonlinear diffraction, ellipticity locking, diffusion-driven solitons, and spatial beam head-on collisions
Electro-optic switching through photorefractive needles
No full textWe demonstrate electro-optic spatial two-dimensional mode switching in a bulk sample of potassium-lithium-tantalate-niobate, mediated by two photorefractive needle solitons of opposite electroholographic charge, mutually embedded in their anisotropic structure. ©2002 Optical Society of America
Intrinsic irreversibility of Markovian chains
Full text linkWe show that for a large class of stationary Markov processes the total variation distance between the final equilibrium distribution and that at a given time is a strongly monotonic vanishing function. We illustrate this for basic paradigmatic processes and discuss how, for systems susceptible to a canonical description, this can be interpreted as a statistical arrow of time that exists besides the standard decrease of free energy
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