QCD expectations for high-energy hadronic collisions

It is argued that perturbative QCD effects could be important in low-momentum transfer hadronic collisions at very high energies and should then give rise to several distinctive phenomena.     

Plasmon-polariton self-induced transparency

The formation and evolution of a localized plasmon-polariton soliton in a metallic cylinder surrounded by a layer of two-level atoms with a frequency close to the plasmon resonance have been investigated. The dynamics of the transverse plasmons in a extended medium is described in the hydrodynamic approximation. It has been shown that the evolution equation can be reduced to Maxwell-Bloch-like equations, which describe self-induced transparency in optics. The effect of losses and nonlinearities caused by the self-action of the electron cloud on the evolution of soliton structures has been studied numerically.     

Plasmon-exciton self-induced transparency

The possibility of forming stable bound plasmon-polariton states in an extended metallic cylinder surrounded by a two-level medium has been investigated. The dynamics of plasmons is described in the hydrodynamic approximation. It has been shown that the equations of motion of charge-density bunches and the Bloch equations for the two-level medium are reduced in certain approximations to integrable equations for both transverse and longitudinal plasmons. In the former case, the initial system of equations after the application of the slow-envelope approximation is reduced to equations equivalent to the Maxwell-Bloch equations. In the latter case, the equations describe wave dynamics beyond the slow-envelope approximation. In the approximation of unidirectional wave propagation, the initial system of equations is reduced to equations related to the reduced Maxwell-Bloch equations. Soliton and breather-like solutions of the derived equations describe plasmon-exciton self-induced transparency.     

A preferred pulse in self-induced transparency

We show that a careful treatment of the propagation of optical pulses in inhomogeneously broadened dielectric media, within the framework of the McCall-Hahn theory, leads to some qualitative deviations from the predictions of McCall and Hahn. These new predictions are in strong conflict with experimental results, and may have interesting implications for theoretical work on “soliton” behavior.     

Polarization effects in self-induced transparency theory

Bloch-Maxwell equations, describing the interaction between two-level atoms and the electromagnetic field, are generalized in the case of an atom with degenerate transition 0 ? 1. The degenerate Bloch-Maxwell model has additional discrete degrees of freedom and makes it possible to investigate the polarization properties of resonance optical phenomena. It is shown that the model is completely integrable. The theory of self-induced transparency for pulses whose polarization is a function of space-time variables is developed.     

Phase-modulated soliton of self-induced transparency

A theory of optical self-induced transparency for a two-component soliton in the presence of phase modulation is developed. It is shown that, under these conditions, it is possible to generate a vector soliton with characteristic parameters of oscillations with the sum and difference frequencies in the region of the carrier wave frequency. Explicit analytical expressions for nonlinear wave parameters under experimentally implemented conditions are given. In particular case, a well-known solution in the form of a breather is obtained.     

Quantum theory of self-induced transparency

It is known that classical electromagnetic radiation at a frequency in resonance with energy splittings of atoms in a dielectric medium can be described using the classical sine-Gordon theory. In this paper we quantize the electromagnetic field and compute some quantum effects by using known results from the sine-Gordon quantum field theory. In particular, we compute the intensity of spontaneously emitted radiation using the thermodynamic Bethe ansatz with boundary interactions.     

On self-induced transparency in laser-plasma interactions

We study fully relativistic nonlinear one-dimensional equations describing steady-state solutions for an electromagnetic wave interacting with a plasma in the self-induced transparency regime. In addition to the well-known solution that corresponds to the transmission of the electromagnetic wave into plasma, another steady-state solution is shown to exist in a certain range of amplitudes of the wave. The latter solution corresponds to total reflection of the incident wave. The coexistence of the two solutions indicates the possibility of hysteretic behavior in the self-induced transparency. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 7, 445–450 (10 October 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Exclusive hadronic processes and color transparency

We review the current status of high energy exclusive processes and color transparency.     

Fluctuations in hadronic and nuclear collisions

We investigate several fluctuation effects in high-energy hadronic and nuclear collisions through the analysis of different observables. To introduce fluctuations in the initial stage of collisions, we use the interacting gluon model (IGM) modified by the inclusion of the impact parameter. The inelasticity and leading-particle distributions follow directly from this model. The fluctuation effects on rapidity distributions are then studied using Landau's hydrodynamic model in one dimension. To investigage further the effects of the multiplicity fluctuation, we use the longitudinal phase-space model, with the multiplicity distribution calculated within the hydrodynamic model, and the initial conditions given by the IGM. Forward-backward correlation is obtained in this way.     

Radiative corrections in hadronic collisions

A general treatment of radiative corrections to any two-body hadronic reaction is presented and applied to specific collisions of pions, kaons and protons with nuclei. The results are found to be significant compared to the accuracies of available data.     

Charge distributions in hadronic collisions

The distribution of charge versus rapidity is examined in the framework of available parton models for multiparticle production in hadron-hadron collisions. Fragmentation models with a twochain Pomeron contribution (based on the dual topological unitarization scheme) are shown to describe rather well the recently measured data on charge distributions in high energypp and πp collisions (140 GeV/c≦p _LAB≦360 GeV/c). Carefully measured charge distributions at still higher energies which will be accessible in the near future offer a possibility of distinguishing between some of the current theoretical approaches.     

Peculiarities of self-induced transparency in noncentrosymmetrical media

Journal of Applied Spectroscopy -     

Optical self-induced transparency in anisotropic dielectric crystals

Optical self-induced transparency for extraordinary waves in anisotropic crystals is theoretically studied. Crystals in which dipole moments of impurity optically active atoms are arbitrarily oriented relative to the optic axis are analyzed in detail. Explicit analytic expressions for the parameters of nonlinear extraordinary wave are presented, which yield known results in limiting cases.