Phase space interference and the WKB approximation for squeezed number states

Squeezed number states for a single mode Hamiltonian are investigated from two complementary points of view. Firstly the more relevant features of their photon distribution are discussed using the WKB wave functions. In particular the oscillations of the distribution and the parity behavior are derived and compared with the exact results. The accuracy is verified and it is shown that for high photon number it fails to reproduce the true distribution. This is contrasted with the fact that for moderate squeezing the WKB approximation gives the analytical justification to the interpretation of the oscillations as the result of the interference of areas with definite phases in phase space. It is shown with a computation at high squeezing using a modified prescription for the phase space representation which is based on Wigner-Cohen distributions that the failure of the WKB approximation does not invalidate the area overlap picture.Comment: 9 pages, 4 figure

ENVIRONMENTAL PROTECTION WITH POLICIES FOR SALE

This paper generalizes the Grossman-Helpman political economy model to characterize the structure of environmental and industry protection for a small open economy when domestic and/or trade policies are the outcome of a noncooperative common agency game between sector-specific producer lobbies and the government. For a consumption externality, the political equilibrium results if domestic and trade policies are available, are production-enhancing protection of organized industries, but the same environmental protection as Pigouvian taxes. Subsidies to organized industries counterbalance environmental taxes when there is a production externality, and it is ambiguous whether domestic or trade policy alone leads to more environmental protection. In addition, this paper demonstrates that the original Grossman-Helpman results arise as a special case that rests on the assumption that only trade policies are available to the government.Environmental Economics and Policy,

Patterns in Wigner-Weyl approach

We present a family of methods, which can describe behaviour of quantum ensembles and demonstrate the creation of nontrivial (meta) stable states (patterns), localized, chaotic, entangled or decoherent from basic localized modes in collective models arising from the quantum hierarchy of Wigner-von Neumann-Moyal equations.Comment: LaTeX2e, w-art.cls, w-thm.sty, w-pamm.clo, 3 pages, 2 figures, presented at GAMM Meeting, 2006, Berlin, German

Localization and pattern formation in Wigner representation via multiresolution

We present an application of variational-wavelet analysis to quasiclassical calculations of solutions of Wigner equations related to nonlinear (polynomial) dynamical problems. (Naive) deformation quantization, multiresolution representations and variational approach are the key points. Numerical calculations demonstrates pattern formation from localized eigenmodes and transition from chaotic to localized (waveleton) types of behaviour.Comment: 3 pages, 3 figures, espcrc2.sty, Presented at VIII International Workshop on Advanced Computing and Analysis Techniques in Physics Research, Section III "Simulations and Computations in Theoretical Physics and Phenomenology", ACAT'2002, June 24-28, 2002, Mosco

Conformal Mapping and Bound States in Bent Waveguides

Is it possible to trap a quantum particle in an open geometry? In this work we deal with the boundary value problem of the stationary Schroedinger (or Helmholtz) equation within a waveguide with straight segments and a rectangular bending. The problem can be reduced to a one dimensional matrix Schroedinger equation using two descriptions: oblique modes and conformal coordinates. We use a corner-corrected WKB formalism to find the energies of the one dimensional problem. It is shown that the presence of bound states is an effect due to the boundary alone, with no classical counterpart for this geometry. The conformal description proves to be simpler, as the coupling of transversal modes is not essential in this case.Comment: 16 pages, 10 figures. To appear in the Proceedings of the Symposium "Symmetries in Nature, in memoriam Marcos Moshinsky