Time derivatives of observables and applications

Eugen Fick, Günter Sauermann

F. Bagarello, Atsushi Inoue, C. Trapani

The problem of exponentiating derivations of quasi ∗ -algebras is considered in view of applying it to the determination of the time evolution of a physical system. The particular case where observables constitute a proper C Q ∗ -algebra is analyzed.

G. Morchio

A long calculation on the basis of a general inequality by Gaveau and Schulman on decoherence energies is reduced to the application of few basic observations on product structures in a class of time evolutions of product states.

Bryan Wilson Roberts

César R. de Oliveira, Oliveira, Mariza Stefanello Simsen

Abstract. Let UF be the Floquet operator of a time periodic hamiltonian H(t). For each positive and discrete observable A (which we call a probe energy), we derive a formula for the Laplace time average of its expectation value up to time T in terms of its eigenvalues and Green functions at the circle of radius e1/T. Some simple applications are provided which support its usefulness.