Information-thermodynamics of Quantum Generalized Measurements

TL;DR

This paper experimentally investigates the thermodynamic costs of generalized quantum measurements on a qubit, introducing a new measurable entropic bound that links information gain and quantum state disturbance, informing quantum information processing.

Contribution

It presents the first experimental validation of an entropic bound for quantum measurements that depends solely on measurable quantities, bridging thermodynamics and quantum information theory.

Findings

Established a measurable entropic bound for quantum measurements.

Demonstrated the transition from weak to invasive measurements.

Provided insights into the thermodynamics of quantum information processing.

Abstract

Landauer's principle introduces a symmetry between computational and physical processes: erasure of information, a logically irreversible operation, must be underlain by an irreversible transformation dissipating energy. Monitoring micro- and nano-systems needs to enter into the energetic balance of their control; hence, finding the ultimate limits is instrumental to the development of future thermal machines operating at the quantum level. We report on the experimental investigation of a bound to the irreversible entropy associated to generalized quantum measurements on a quantum bit. We adopted a quantum photonics gate to implement a device interpolating from the weakly disturbing to the fully invasive and maximally informative regime. Our experiment prompted us to introduce a bound taking into account both the classical result of the measurement and the outcoming quantum state; unlike previous investigation, our new entropic bound is based uniquely on measurable quantities. Our results highlight what insights the information-theoretic approach can provide on building blocks of quantum information processors.