Yuval Gefen

Sociophysics: A new approach of sociological collective behaviour. I. mean‐behaviour description of a strike

A new approach to the understanding of sociological collective behaviour, based on the framework of critical phenomena in physics, is presented. The first step consists of constructing a simple mean‐behaviour model and applying it to a strike process in a plant. The model comprises only a limited number of parameters characteristic of the plant considered and of the society. A dissatisfaction function is introduced with a basic principle stating that the stable state of the plant is a state which minimizes this function. It is found that the plant can be in one of two phases: the “collective phase” and the “individual phase.” These two phases are separated by a critical point, in the neighbourhood of which the system is very sensitive to small changes in the parameters. The collective phase includes a region of parameters for which the system has two possible states: a “work state” and a “strike state.” The actual state of the system depends on the parameters and on the “history of the system.” The irreve...

QUASIPARTICLE LIFETIME IN A FINITE SYSTEM : A NONPERTURBATIVE APPROACH

The problem of electron-electron lifetime in a quantum dot is studied beyond perturbation theory by mapping onto the problem of localization in the Fock space. Localized and delocalized regimes are identified, corresponding to quasiparticle spectral peaks of zero and finite width, respectively. In the localized regime, quasiparticle states are single-particle-like. In the delocalized regime, each eigenstate is a superposition of states with very different quasiparticle content. The transition energy is

Phase transitions on fractals. III. Infinitely ramified lattices

{\ensuremath{\epsilon}}_{c}\ensuremath{\simeq}\ensuremath{\Delta}(g/\mathrm{ln}g{)}^{1/2}

New quantum oscillations in current driven small junctions

, where

Aharonov-Bohm interferometry with interacting quantum dots: Spin configurations, asymmetric interference patterns, bias-voltage-induced Aharonov-Bohm oscillations, and symmetries of transport coefficients

\ensuremath{\Delta}

Variable-range hopping conductivity in granular materials

is mean level spacing, and

Geometric Nature of the Environment-Induced Berry Phase and Geometric Dephasing

g

Berry phase in a nonisolated system.

is the dimensionless conductance. Near

Coherence and Partial Coherence in Interacting Electron Systems

{\ensuremath{\epsilon}}_{c}

Onset of dissipation in Zener dynamics: Relaxation versus dephasing

there is a broad critical region not described by the golden rule.