[en] It is clear that the study of e/sup +/e/sup -/ collisions has the power to probe what lies beyond the standard model. The authors are now designing and building the colliders which will take us into new energy regions. If nature cooperates, we will learn a great deal

[en] The previously derived universal expression for the plasma permittivity is used to solve the problem of absorption of a short laser pulse incident on a semibounded solid-dense plasma. It is shown that the results of the exact theory may differ significantly from those obtained with the generally accepted models, especially in a weakly collisional regime corresponding to temperatures in the range 0.5-1 keV.

[en] We examine the nature and statistical properties of electron-electron collisions in the recollision process in a strong laser field. The separation of the double ionization yield into sequential and nonsequential components leads to a bell-shaped curve for the nonsequential probability and a monotonically rising one for the sequential process. We identify key features of the nonsequential process and connect our findings in a simplified model which reproduces the knee shape for the probability of double ionization with laser intensity and associated trends.

[en] An introduction is given to the understanding of plasmons in a solid. The quantum of excitation associated with the collective motion of the electron gas is known as a 'plasmon'. It is noted that the quantum of energy associated with a plasmon on the surface of a metal differs from those from inside a metal or at metal-air or metal-metal interfaces. Excitation of plasmons by laser beams have been attempted. It has been realised that study of plasmons is of help in probing optical properties of metals, in understanding voids in metals, and also in the study of stellar dust. (A.K.)

[en] The spin interference and nonideal effects on electron-electron collisions are investigated in nonideal plasmas. An effective pseudopotential model taking into account the screening and nonideal effects is applied to describe the electron-electron interaction potential in nonideal plasmas. The total spin states of the collision system are considered to obtain high-energy electron-electron collision cross sections. The results show that the differential collision cross section is found to decrease with increasing nonideality plasma parameter γ in the region 0<γ<2 and, however, it increases in the region 2<γ<4. It is found that the spin interference and nonideal screening effects are especially important at the scattering angle θ_L=π/4. It should also be noted that the differential cross sections have minima near γ=2 and the nonideal effect is found to be more significant at the minima

[en] We explore the crossover from classical plasma to quantum Fermi liquid behavior of electrons in dense plasmas. To this end, we analyze the evolution with density and temperature of the momentum lifetime of a test electron introduced in a dense electron gas. This allows us (1) to determine the boundaries of the crossover region in the temperature-density plane and to shed light on the evolution of scattering properties across it, (2) to quantify the role of the fermionic nature of electrons on electronic collisions across the crossover region, and (3) to explain how the concept of the Coulomb logarithm emerges at a high enough temperature but disappears at a low enough temperature.

[en] The effect of the electron hole scattering in a Fermi gas with a localized hole at the centre is investigated, with electron-electron interactions treated phenomenologically. When resonance scattering exists, self-consistency is achieved by employing a generalized Friedel sum rule

No abstract available

[en] Two-electron collisions are studied while taking into account the propagation delay of electromagnetic fields. The method used here is an expansion in powers of v/c in the relativistic equations of motion (Lorentz-Abraham-Dirac equation). One stresses the impact which the deviation from the hamiltonian behaviour could bear upon the microscopic explanation of thermodynamic irreversibility

[en] We study metastable-state formation in the one-dimensional model of a quantum ballistic contact, in which the contact is represented by a potential barrier with electron-electron interaction localized therein. It is shown that when the interaction parameter exceeds a critical value, a metastable state with spontaneous spin polarization of the barrier is formed. The difference between the grand potentials of the metastable and globally stable states tends to zero at the critical point; therefore, the metastable state manifests itself in transport even at low temperatures and its effect gradually increases with temperature. The main effect is a decrease in the conductance with increasing temperature, which occurs in a certain range of the barrier-region potential, similar to that observed during the formation of the well-known 0.7 conductance anomaly