

Oxford University
Vlatko Vedral
Oxford University
Co-Investigators
Marco Genovese, INRIM Torino
Project Title
Agent-based irreversibility in quantum theory: theory and experiment
Project Summary
The microscopic physical laws seem to have no place for agents. Yet agents are key in macroscopic phenomena such as life, the physics of engines and computers. Here we propose a radically new route to accommodating agents in fundamental physics. We use agents to crack an old-age problem, that of reconciling macroscopic irreversibility with the reversibility of the microscopic world. For example, the macroscopic process dissipating the energy of a piston into heat inside an engine is irreversible: it is impossible to revert the heat back into useful work. This irreversibility is mandated by the second law of thermodynamics. Yet, at the microscopic scale, atoms constituting the engine and its surroundings display perfectly reversible trajectories: they can move both forward and backwards in time. Here we show that agents offer a surprising way to reconcile these two views. First, we express irreversibility via agents – stating that an arbitrarily accurate agent performing a transformation in one direction is possible (e.g. converting heat into work), but it is impossible for the reverse transformation. Then we show theoretically and experimentally how agents ultimately reconcile the microscopic world, where dynamical trajectories are reversible; and the macroscopic world, where that agent-based irreversibility is allowed.
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