title: Condensation of fluctuations in and out of equilibrium.
abstract: Condensation of fluctuations is an interesting phenomenon conceptually distinct from condensation on average. One striking feature is that, contrary to what happens on average, condensation of fluctuations may occur even in the absence of interaction. The explanation emerges from the duality between large deviation events in the given system and typical events in a new and appropriately biased system. This phenomenon is investigated in the context of the Gaussian model, chosen as a paradigmatical noninteracting system, before and after an instantaneous temperature quench. It is shown that the bias induces a mean-field-like effective interaction responsible for the condensation on average. Phase diagrams, covering both the equilibrium and the off-equilibrium regimes, are derived for observables representative of generic behaviors.
authors.affiliation: Dipartimento di Fisica "E.R. Caianiello" and CNISM Unità di Salerno, Università di Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy and Kavli Institute for Theoretical Physics China, CAS, Beijing 100190, China.
authors.forename: Marco
authors.initials: M
authors.lastname: Zannetti
authors.affiliation: Dipartimento di Fisica "E.R. Caianiello" and CNISM Unità di Salerno, Università di Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Corberi
authors.affiliation: Dipartimento di Fisica, Università di Bari and INFN Sezione di Bari, via Amendola 173, 70126 Bari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gonnella
mesh_terms: D008962:Models, Theoretical; D016011:Normal Distribution; D044367:Phase Transition; D013816:Thermodynamics