Nonequilibrium limits to precision and sensitivity

Away from equilibrium, energy can serve as a resource that opens the door to what seems like limitless potential for novel phenomena. To date, however, our understanding of energy’s role has been largely gleaned through individual case studies, leaving it an open question to identify universal principles. In this talk, I will discuss how advances in the field of nonequilibrium thermodynamics allow us to make such general quantitative statements. The first is a bound that quantifies how dissipation shapes fluctuations far from equilibrium. Apart from its intrinsic allure as a universal relation, I will discuss how it can be used to rationalize limits to power fluctuations in steady-state heat engines, probe the energetic efficiency of molecular motors, and offer energetic constraints on the precision of biochemical clocks. The second is an inequality - akin to the Fluctuation-Dissipation theorem but valid arbitrarily far from equilibrium - that constrains a system’s sensitivity by its dynamical structure. To illustrate this result, I will draw on examples from biophysics, where the effectiveness of numerous biochemical systems depends on being exquisitely sensitive to changes in chemical inputs. We will see how these predictions rationalize known energetic requirements of some common biochemical motifs and provide new limits to others.