Experimental Measurement of Information-Content in Nonequilibrium Systems

by Prof. Felix Ritort (Facultat de Física, Departament de Física de la Matèria Condensada, Universitat de Barcelona)

Tuesday 19 Jun 2018, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica - Ed. G. Marconi)

Biology is intrinsically noisy at all levels, from molecules to cells, tissues, organs, communities and ecosystems. While thermodynamic processes in ordinary matter are driven by free-energy minimization, living matter and biology delineate a fascinating nonequilibrium state predominantly governed by information flows through all organizational levels. Whereas we know how to measure energy and entropy in physical systems we have poor knowledge about measuring information-content in general. Recent developments in the fields of stochastic thermodynamics and thermodynamic-information feedback combined with single molecule experiments how the way to define information-content in nonequilibrium systems. In this talk I will describe how to measure information-content in two classes of nonequilibrium systems. First, I will introduce the Continuous Maxwell Demon, a new paradigm of information-to-energy conversion, and demonstrate how work extraction beats the Landauer limit without violating the second law. Next, I will demonstrate the validity of a fluctuation theorem in nonequilibrium systems under continuous-time feedback and show how to measure information-content in such conditions. Second, I will introduce a mutational ensemble of DNA hairpin folders and show how to measure information-content in this context. A definition of information-content applicable to generic disordered populations is proposed. All results are experimentally verified in single molecule pulling experiments.