On the time evolution of fermionic natural occupation numbers
13/12/2019 at 11:30 Department of Physics. Aula Caldirola.
Carlos Benavides, Institut für Physik Martin-Luther-Universität Halle-Wittenberg.
Pure fermionic states obey not only the Pauli exclusion principle but a stronger set of generalized Pauli constraints. This recent mathematical insight can be used to study the time evolution of highly correlated electronic systems. In this talk I will derive an approximate equation for the time evolution of the natural occupation numbers for such fermionic systems. The evolution of these numbers is connected to a geometrical and a dynamical terms attached to some of the Slater determinants appearing in the configuration-interaction expansion of the wave function. Our approach becomes exact for highly symmetric systems whenever the wave function possesses as many Slater determinants as independent occupation numbers.