In 1961, Rolf Landauer pointed out that resetting a binary memory requires a minimum energy of kBT ln(2). However, once written, any memory is doomed to lose its content if no action is taken. To avoid memory losses, a refresh procedure is periodically performed. In this talk, we present a theoretical and experimental study of a sub-kBT 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: no memory can last forever.
Luca Gammaitoni is professor of experimental physics at the University of Perugia (Italy) and director of the Noise in Physical Systems (NiPS) Laboratory. He is also the founder of Wisepower srl, a university spin-off company. He obtained the Ph.D. in physics from the University of Pisa in 1990. Since then he has developed wide international experience with collaborations in Europe, Japan, and the U.S. His scientific interests span from noise phenomena in dynamical physical systems to non-equilibrium thermodynamics and energy transformations at the micro and nanoscale, including the physics of computing. He has authored over 200 papers in top-level scientific journals and a few books. He is also the author of 10 patents. His papers have been cited more than 34,000 times with an h-index 77 [Google Scholar]. More information: www.nipslab.org
Professor Wolfgang Porod, Electrical Engineering