Università Cattolica del Sacro Cuore - Sede di Brescia
Dipartimento di Matematica e Fisica “Niccolò Tartaglia”
Ferromagnetism in finite spin chains
Superradiance transition and Transport through nanostructures
Abstract
In this talk we will review some research topics we have been working on in the last years.
First we will focus on many body spin systems with anisotropy showing the existence
of a topological non-connectivity threshold and its consequence on statistical properties and
magnetic reversal times, which are essential to understand the origin of ferromagnetism in
finite systems.
In the second part of the talk, using an energy-independent non-Hermitian Hamiltonian approach to open systems, we fully describe transport through a sequence of potential barriers as external barriers are varied. Analyzing the complex eigenvalues of the non-Hermitian Hamiltonian model, a transition to a superradiant regime is shown to occur. Transport properties undergo a strong change at the superradiance transition, specifically a drastic change in the structure of resonances is demonstrated.
Relatore
Dr. Luca Celardo
Università Cattolica del Sacro Cuore
Giovedì 15 ottobre 2009
ore 16.00, Aula 10
Via dei Musei, 41 - Brescia