Experimental perspectives for systems based on long-range interactions

Abstract

The possibility of observing phenomena peculiar to long-range interactions, and morespecifically in the so-called quasi-stationary state (QSS) regime, is investigated within theframework of two devices, namely the free-electron laser (FEL) and the collectiveatomic recoil laser (CARL). The QSS dynamics has been mostly studied using theHamiltonian mean-field (HMF) toy model, demonstrating in particular the presence offirst-order and second-order out-of-equilibrium phase transitions from magnetized tounmagnetized regimes. Here, we give evidence of the strong connections between the HMFmodel and the dynamics of the two aforementioned devices, and we discuss theperspectives for observing some specific QSS features experimentally. In particular, adynamical analog of the phase transition is present in the FEL and in the CARL in itsconservative regime. As regards the dissipative CARL, a formal link is establishedwith the HMF model. For both FEL and CARL, calculations are performed withreference to existing experimental devices, namely the FERMI@Elettra FEL underconstruction at Sincrotrone Trieste (Italy) and the CARL system at LENS in Florence(Italy).