title: Ensemble inequivalence in systems with wave-particle interaction.
abstract: The classical wave-particle Hamiltonian is considered in its generalized version, where two modes are assumed to interact with the coevolving charged particles. The equilibrium statistical mechanics solution of the model is worked out analytically, both in the canonical and the microcanonical ensembles. The competition between the two modes is shown to yield ensemble inequivalence, at variance with the standard scenario where just one wave is allowed to develop. As a consequence, both temperature jumps and negative specific heat can show up in the microcanonical ensemble. The relevance of these findings for both plasma physics and free electron laser applications is discussed.
authors.affiliation: Dipartimento di Fisica e Astronomia and CSDC, Università degli Studi di Firenze, CNISM and INFN, via G. Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Tarcísio N
authors.initials: TN
authors.lastname: Teles
authors.affiliation: Dipartimento di Fisica e Astronomia and CSDC, Università degli Studi di Firenze, CNISM and INFN, via G. Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Duccio
authors.initials: D
authors.lastname: Fanelli
authors.affiliation: Dipartimento di Fisica e Astronomia and CSDC, Università degli Studi di Firenze, CNISM and INFN, via G. Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ruffo