Quantum Computation and Information Seminar 

25/07/2008, 15:00 — 16:00 — Room P4.35, Mathematics Building
Massimo Palma, U Palermo

Entanglement and ergodicity in randomly colliding qubits

The dynamics of a single qubit randomly colliding with an environment consisting of N qubits is discussed with particular interest for the rate of approach to equilibrium and to the rate of entanglement creation. We will show in particular that even when the environment consists of just two qubits the system reaches an equilibrium state which coincides with a pure random state of three qubits. Furthermore the time average and the ensemble averages of the quantities used to characterize the approach to equilibrium (purity and tangles) coincide, a signature of ergodic behavior.