Our group has significantly contributed to fields related to the study of fluctuations and fluctuation-induced phenomena, like thermodynamics of fluctuating systems or response of far from equilibrium systems. In the present, several research projects in our group aim at applying or generalizing these results to relevant biological problems.
H. Casimir proved in 1948 that two metallic parallel plates attract each other due to the quantum fluctuations induced by the electric field of the vacuum between the plates [1]. The dependence of this force with the temperature was calculated by Lifschitz [2].
The recent technological advances in micromanipulation and force-sensing techniques have brought access to the dynamics and energy changes that affect mesoscopic physical systems described by few degrees of freedom. For systems of microscopic and nanoscopic scale, the thermal fluctuations of the surrounding environment become relevant.
The Jarzynski equality, introduced in 1997, established an exact relationship that involves the work fluctuations of processes arbitrarily far from equilibrium [1]. Later, Crooks' theorem [2, 3] showed that the mentioned equality is consequence of some symmetry properties under time reversal of the microscopic evolution of the system, both Hamiltonian or stochastic (Langevin equation).
Fluctuation-dissipation relations (FDR) have been a crucial tool in Statistical Physics. They relate the response of a system slightly removed from equilibrium to equilibrium properties and allow to connect transport coefficients to microscopic properties [1].
Granular matter, because of lack of energy conservation, are systems out of equilibirum. Then usual approaches based on Thermodynamics of Statistical mechanics are not applicable a priori. Phenomenology in these systems is very rich.