KTH/Nordita/SU seminar in Theoretical Physics

Spontaneous reversal of irreversible processes in a many-body Hamiltonian evolution

by Francesco Calogero (FC, Physics Department, University of Rome "La Sapienza")

FA31 (FA31)



An autonomous Hamiltonian model will be presented and discussed. It is a modified version of the most-general translation-invariant N-body problem (N is arbitrary, as well as the dimensions of the ambient space). It features an arbitrary real parameter T and possesses the following two properties, whose coexistence is clearly remarkable. First: all the solutions of this model are completely periodic (i. e., periodic in all degrees of freedom: positions and velocities of the N particles), with the (arbitrarily assigned) period T. Second: the generic solution of this model (starting from generic initial data) has a behavior that essentially coincides with that of the original (standard) many-body problem (with arbitrary interparticle forces), for times much smaller than T. Hence over such (finite but arbitrarily large) times the dynamics implied by our model generally entails the standard statistical dynamics and thermodynamics, entailing the thermodynamic irreversibility of physical processes; yet its exact evolution is competely periodic...This is joint work with François Leyvraz.