RareNoise: non‐equilibrium fluctuations in gravitational wave detectors

by Livia CONTI (INFN Sezione di Padova)

Wednesday 27 Jan 2010, 11:00 → 13:00 Europe/Rome

LNL meeting room (INFN LNL)

Research of non‐equilibrium statistical mechanics is facing a renewed interest, mainly on the impulse of the development of molecular machines and nanostructured materials: even if a general theory is still lacking, several intermediate general results have been proven that cover a wide variety of phenomena and observables. In contrast to the general assumption, we point out that ground based gravitational wave detectors are non‐equilibrium instruments, for instance due to laser power absorption and thermal compensation schemes. We discuss how non-equilibrium effects would affect gravitational wave detectors if they are proved to be not‐negligible. We describe the RareNoise research project that aims at sizing such effects with a systematic experimental, numerical and theoretical study of the spontaneous fluctuations of macroscopic oscillators in non-equilibrium steady‐states. We show also a first application of the non‐equilibrium concepts to gravitational wave detectors, namely the AURIGA bar detector: here we evidence an asymmetry in the probability density function of the heat exchanged between the oscillator and the thermal bath.