Emergence of Constructor-Based Irreversibility in Quantum Systems: Theory and Experiment

Author: Chiara Marletto, Vlatko Vedral
Journal: Phys. Rev. Lett. 128, 080401
Date: 23 February 2022
Affiliations: Clarendon Laboratory, University of Oxford, UK // Fondazione ISI, Torino, Italy // Centre for Quantum Technologies, National University of Singapore, Singapore // Department of Physics, National University of Singapore, Singapore
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How irreversibility arises in a universe with time-reversal symmetric laws is a central problem in physics. In this Letter, we discuss a radically different take on the emergence of irreversibility, adopting the recently proposed constructor theory framework. Irreversibility is expressed as the requirement that a task is possible, while its inverse is not. We prove the compatibility of such irreversibility with quantum theory’s time-reversal symmetric laws, using a dynamical model based on the universal quantum homogenizer. We also test the physical realizability of this model by means of an experimental demonstration with high-quality single-photon qubits.