Effects of mode-mode and isospin-isospin correlations on domain formation of disoriented chiral condensates

The effects of mode-mode and isospin-isospin correlations on nonequilibrium chiral dynamics are investigated by using the method of the time dependent variational approach with squeezed states as trial states. Our numerical simulations show that large domains of the disoriented chiral condensate (DCC) are formed due to the combined effect of the mode-mode and isospin-isospin correlations. Moreover, it is found that, when the mode-mode correlation is included, the DCC domain formation is accompanied by the amplification of the quantum fluctuation, which implies the squeezing of the state. However, neither the DCC domain formation nor the amplification of the quantum fluctuation is observed if only the isospin-isospin correlation is included. This suggests that the mode-mode coupling plays a key role in the DCC domain formation.Comment: 10 pages, 11 figures; Correction of an error in Fig.

Time-Evolution of a Collective Meson Field by the Use of a Squeezed State

A time-evolution of quantum meson fields is investigated in a linear sigma model by means of the time-dependent variational approach with a squeezed state. The chiral condensate, which is a mean field of the quantum meson fields, and quantum fluctuations around it are treated self-consistently in this approach. The attention is payed to the description of the relaxation process of the chiral condensate, where the energy stored in the mean field configuration flows to the fluctuation modes. It is shown that the quantum fluctuations play an important role to describe this relaxation process.Comment: 18 pages, 22 postscript figures, uses PTPTeX.st

Nonequilibrium chiral dynamics by the time dependent variational approach with squeezed states

We investigate the inhomogeneous chiral dynamics of the O(4) linear sigma model in 1+1 dimensions using the time dependent variational approach in the space spanned by the squeezed states. We compare two cases, with and without the Gaussian approximation for the Green's functions. We show that mode-mode correlation plays a decisive role in the out-of-equilibrium quantum dynamics of domain formation and squeezing of states.Comment: 5 pages, 4 figures. RevTex, version to appear in Phys. Rev. C. Rapid Communicatio

Normal modes of a quasi-one-dimensional multi-chain complex plasma

We studied equally charged particles, suspended in a complex plasma, which move in a plane and interact with a screened Coulomb potential (Yukawa type) and with an additional external confining parabolic potential in one direction, that makes the system quasi-one-dimensional (Q1D). The normal modes of the system are studied in the presence of dissipation. We also investigated how a perpendicular magnetic field couples the phonon modes with each other. Two different ways of exciting the normal modes are discussed: 1) a uniform excitation of the Q1D lattice, and 2) a local forced excitation of the system in which one particle is driven by e.g. a laser. Our results are in very good agreement with recent experimental findings on a finite single chain system (Phys. Rev. Lett. {\bf 91}, 255003 (2003)). Predictions are made for the normal modes of multi-chain structures in the presence of damping.Comment: 15 pages, 14 figures, accepted for publication on PR

Photon emission by an ultra-relativistic particle channeling in a periodically bent crystal

This paper is devoted to a detailed analysis of the new type of the undulator radiation generated by an ultra-relativistic charged particle channeling along a crystal plane, which is periodically bent by a transverse acoustic wave, as well as to the conditions limiting the observation of this phenomenon. This mechanism makes feasible the generation of electromagnetic radiation, both spontaneous and stimulated, emitted in a wide range of the photon energies, from X- up to gamma-rays

Channeling of Positrons through Periodically Bent Crystals: on Feasibility of Crystalline Undulator and Gamma-Laser

The electromagnetic radiation generated by ultra-relativistic positrons channelling in a crystalline undulator is discussed. The crystalline undulator is a crystal whose planes are bent periodically with the amplitude much larger than the interplanar spacing. Various conditions and criteria to be fulfilled for the crystalline undulator operation are established. Different methods of the crystal bending are described. We present the results of numeric calculations of spectral distributions of the spontaneous radiation emitted in the crystalline undulator and discuss the possibility to create the stimulated emission in such a system in analogy with the free electron laser. A careful literature survey covering the formulation of all essential ideas in this field is given. Our investigation shows that the proposed mechanism provides an efficient source for high energy photons, which is worth to study experimentally.Comment: 52 pages, MikTeX, 14 figure

Development and application of radar reflectometer using micro to infrared waves

Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, including radio astronomy, alien substance detection, plasma diagnostics, airborne and space-borne imaging radars called as synthetic aperture radars, and living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic principles. The diagnostics are classified as active and passive systems. Specifically, active radar reflectometry has become of importance in various applications due to the possibility of high localization and accessibility of the measurements as well as the non-invasive nature of the systems. In this paper, recent development and application of radar reflectometers are described. The key words are profile reflectometry, fluctuation reflectometry, imaging radar (optics imaging and synthetic aperture imaging), and radio-optics fusion technology in order to improve the spatial resolution