European Physical Journal B (14346028)36(1)pp. 115-118
A new type of noised induced phase transitions is proposed. It occurs in noisy systems with dynamical traps. Dynamical traps are regions in the phase space where the regular "forces" are depressed substantially. By way of an example, a simple oscillatory system {x,v = x} with additive white noise is considered and its dynamics is analyzed numerically. The dynamical trap region is assumed to be located near the x-axis where the "velocity" v of the system becomes sufficiently low. The meaning of this assumption is discussed. The observed phase transition is caused by the asymmetry in the residence time distribution in the vicinity of zero value "velocity". This asymmetry is due to a cooperative effect of the random Langevin "force" in the trap region and the regular "force" not changing the direction of action when crossing the trap region. © EDP Sciences, Società Italiana di Fisica, and Springer-Verlag 2003.
Proceedings of SPIE - The International Society for Optical Engineering (1996756X)5249pp. 249-260
A systematic design method for quasi-symmetrical wide angle systems is presented. The method starts with thin lens predesign of half of the system using most available glasses. The aperture stop position is determined for reducing astigmatism and the system is made symetrical about it for eliminating Coma, Lateral colour and Distortion. Finally the system is optimized using Eikonal software for infinite conjugate.
Journal of Modern Optics (13623044)51(13)pp. 1963-1982
A method for astigmatism calculations along any skew ray is presented. This is useful in the case of extremely wide angle optical systems (and not only imaging systems), where skew ray aberrations are most dominant, but it is essential in the case of systems which are not rotationally symmetric, where all the rays may be skew. Equations relating the position of the astigmatic foci before and after refraction or reflection are derived from the analysis of infinitesimal wave fronts in the immediate neighbourhood of the point of incidence of any ray, but particularly the central ray of any pencil on an optical surface. The method is then illustrated and checked with representative numerical examples. © 2004 Taylor & Francis Group, LLC.
Journal of the Physical Society of Japan (13474073)73(9)pp. 2413-2423
Temporal evolution of atomic properties including the population inversion and quantum fluctuations of atomic dipole variables are discussed in three variants of the two-photon q-deformed Jaynes-Cummings model. The model is based on the generalized deformed oscillator algebra, [Â,Â+] = (N̂ + 1)f2(N + 1) - N̂f2(N̂) in which f(N̂) as a function of number operator N̂ determines not only the intensity dependence of atom-field coupling, when the model Hamiltonian is expressed in terms of non-deformed field operators, but also the structure of initial state of the radiation field. With the field initially being in three different types of q-deformed coherent states, each of them corresponding to a particular form of the function f(N̂), the quantum collapse and revival effects as well as atomic dipole squeezing are studied for both on- and off-resonant atom-field interaction. Particularly, it is shown that for nonzero detuning the atomic inversion exhibits superstructures, which are absent in the non-deformed Jaynes-Cummings model, and the magnitude of dipole squeezing may be increased. © 2004 The Physical Society of Japan.
Journal of Physics B: Atomic, Molecular and Optical Physics (09534075)37(16)pp. 3321-3338
The Faddeev-Watson-Lovelace (FWL) treatment, in a second-order approximation, and an active electron model have been applied to calculate the single-electron capture differential cross sections from K-, L- and M-shells of many-electron atoms by protons at medium and high (but non-relativistic) impact energies. The radial part of the wavefunction for the active electron was obtained by constructing suitable bases from merging hyperbolic cosine functions with Slater-type radial ones. Converting the Schrödinger-like equation obtained from Hartree-Fock theory gives the effective potential, which is experienced by the active electron in the target atom. A simple analytic radial function composed of a Coulomb and a Yukawa potential was fitted to the effective potential. Near-the-shell two-body T-matrices, electronic-nuclear and inter-nuclear partial amplitudes are calculated to obtain the electron capture differential cross sections between various shells of the target atom and the ground state of atomic hydrogen formed, Theoretical results are compared with the available experimental data on helium, neon and argon atoms at different energies.
Progress of Theoretical Physics (13474081)112(5)pp. 797-809
Considering a simple generalization of the (p, q)-deformed boson oscillator algebra, which leads to a two-parameter deformed bosonic algebra in an infinite dimensional subspace of the harmonic oscillator Hilbert space without first finite Fock states, we establish a new harmonic oscillator realization of the deformed boson operators based on the Bogoliubov (p, q)-transformations. We obtain exact expressions for the transformation coefficients and show that they depend on arbitrary functions of p and q which can be interpreted as the parameters of the (p, q)-deformed GL(2, C) group. We also examine the existence and structure of the corresponding deformed Fock-space representation for our problem.
Applied Optics (21553165)43(35)pp. 6481-6486
A compact mid-infrared (MIR) laser spectrometer based on difference-frequency generation (DFG) is applied as a portable and sensitive gas sensor for industrial process control and pollutant monitoring. We demonstrate the performance of such a MIR DFG gas sensor by recording the absorption spectra of the carbon monoxide (CO) P(28) absorption line in the atmosphere of a gas-fired glass melting furnace. For a gas temperature of approximately 1100°C, the CO concentration in the recuperator channel is measured to be 400 parts per million. © 2004 Optical Society of America.
Proceedings of SPIE - The International Society for Optical Engineering (1996756X)5249pp. 740-745
The different methods of optical systems' optimization such as Newton and Least Squares along with their modification are discussed. Monte-Carlo technique as an statistical method which can overcome the shortcoming of those classic methods (such as the rate of convergence, the possibility of finding the overall minimum and avoiding local minima) is presented and compared with the other ones. An numerical example is presented to verify the method.
