For distribution - thanks

[CM ICTP - Trieste]

SEMINAR on  Disorder and strong electron correlations



Thursday, 10 May   -    11:00 a.m.



Lecture Room 'C',  Main Bldg.- terrace level


S. KEHREIN    ( Ludwig-Maximilians Universität München )

" Real time evolution of quantum many-particle systems: The flow 
equation approach"


Abstract

	The analytical evaluation of the real time evolution of a quantum 
many-particle system far out of equilibrium poses a challenging 
problem.  Without prior knowledge about the long-time behavior, 
perturbative calculations suffer from spurious terms (secular terms),  
which grow in an uncontrolled way for large times.  The flow equation 
approach (infinitesimal unitary transformation approach) can overcome 
some of these problems by studying the real time evolution of 
observables in the Heisenberg picture in a suitable energy-diagonal 
basis.  This basis is obtained by an approximate renormalization group- 
like diagonalization of the Hamiltonian. In this talk I will review the 
method and show its application to various quantum many-particle 
problems.