Séminaire de Valerio Scarani: Irreversibility as “irretrodictability”

Irreversibility as “irretrodictability”

Valerio Scarani, Centre for Quantum Technologies and Department of Physics, National University of Singapore

Both classical and quantum theory hold that every change is reversible at the fundamental level, although we perceive almost everything as irreversible processes. Yet, physicists are not urging to label that perception as illusory: for most, the Second Law of thermodynamics is untouchable, so aberrant the idea of inexhaustible energy is. Building on a narrative pioneered by Watanabe in the 1960s, I shall present an approach to the Second Law as a form of statistical inference given partial information. Irreversibility is unavoidable because it translates the asymmetry between prediction and retrodiction on a given process. This viewpoint applies to both classical and quantum systems. Applied to the “fluctuation relations” that have been the preferential tools to address irreversibility in the last two decades, it both simplifies their derivation and expands their scope.

References:
F. Buscemi, V. Scarani, Phys. Rev. E 103, 052111 (2021)
C. Aw, F. Buscemi, V. Scarani, AVS Quantum Sci. 3, 045621 (2021), https://arxiv.org/abs/2106.08589.