Seminari Generali

Memory does not last forever

by Luca Gammaitoni (University of Perugia )

Aula Conversi (Dip. di Fisica - Edifcio G. Marconi)

Aula Conversi

Dip. di Fisica - Edifcio G. Marconi


The act of remembering is of fundamental importance in human life. Not only do manmade objects such as monuments and landscapes require maintenance to counterbalance their deterioration, but also biological systems are subject to the never-ending task of preserving shapes and functionalities by fighting the universal tendency of entropy to increase. In this talk we discuss a general stochastic dynamic model that describes the time evolution of a digital memory. We present theoretical results and an experiment on a microelectromechanical system, to evaluate the minimum energy required to preserve one bit of information over time. Two main conclusions are drawn: (i) in principle, the energetic cost to preserve information for a fixed time duration with a given error probability can be arbitrarily reduced if the refresh procedure is performed often enough, and (ii) the Heisenberg uncertainty principle sets an upper bound on the memory lifetime.

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Organized by

Irene Giardina