Obiettivo The first part of the research concerns a study of many-body phenomena in collisions of highly excited atoms. Electrons in highly excited states of many-electron atoms, being in average very far from the core, experience it as a spherically symmetric Coulomb potential. For this reason such excited states can be described as the states of a hydrogen atom. In particular, the wave functions are characterized by the main quantum number n. The typical values of n are very large: n~100. Since the Einstein coefficients governing the emission processes decay rapidly at large n (as 1/n3), the highly excited or Rydberg atoms are very stable objects with a considerable life time. The long life time together with their enormous size (r~n2aB) are the cause of their domination in recombination processes in electronic discharges and low density plasma. Such processes are of considerable interest for atomic spectroscopy, astrophysics and for plasma kinetics. Despite extensive theoretical activity in the area of highly excited atoms, one principal problem remains unaddressed. This is the problem of many-body effects. All the previous approaches have been exclusively single particle. Meanwhile, many-body effects may be essential when highly states include many electrons. For a large number of excited electrons (square root of N >> 1) a statistical description can be used. The appropriate methods for many-body systems with finite number of particles have already been developed in the context of physics of nuclei. The present case has its own specifics related to the long-distant character of the Coulomb interaction. Since electrons in Rydberg atoms are very far from the core, its potential can be treated semi-classically. In this approach one can take advantage from the fact that all Green's functions are rapidly oscillating functions of differences of coordinates and slow functions of their sums. The second part of the research aims to deal with the statistical mechanics of neural networks and spin-glasses. Four concrete problems will be studied: physics of the statistical systems in which the disorder variables are partially annealed; nature of the replica symmetry breaking states which is known to take place in various neutral network models; properties of the low temperature phase and the phase transition in the Ising systems with random fields, where the replica symmetry breaking phenomena could play the crucial role; and ageing phenomena in spin-glass systems with hierarchical structure of metastable states Programma(i) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Argomento(i) 13 - High Energy Physics Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD Contributo UE Nessun dato Indirizzo Keble Road 1- Denys Wilkinson Building OX1 3RH OXFORD Regno Unito Mostra sulla mappa Costo totale Nessun dato Partecipanti (3) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto Russian Academy of Sciences Russia Contributo UE Nessun dato Indirizzo 142432 Chernogolovka, Moscow Mostra sulla mappa Costo totale Nessun dato Russian Academy of Sciences Russia Contributo UE Nessun dato Indirizzo 117924 Moscow Mostra sulla mappa Costo totale Nessun dato University of Oxford Regno Unito Contributo UE Nessun dato Indirizzo 1 Keble Road OX1 3NP Oxford Mostra sulla mappa Costo totale Nessun dato
