From compatibility of measurements to exploring Quantum Darwinism on NISQ

TL;DR

This paper investigates the emergence and breakdown of Quantum Darwinism in quantum systems, providing tools to benchmark quantum features on NISQ hardware like IonQ and IBM quantum computers.

Contribution

It introduces a method to analyze Quantum Darwinism's breaking point and applies it to assess the quantum nature of NISQ devices.

Findings

Quantum Darwinism can be effectively tested on NISQ hardware.

Breakdown of Quantum Darwinism correlates with non-classical measurement statistics.

Benchmarking tools for quantum hardware based on Quantum Darwinism are proposed.

Abstract

Quantum Darwinism explains how tenets of classical reality, such as objectivity and repeatability, emerge within a quantum universe. As a mathematical framework, Quantum Darwinism also provides guiding principles that determine what physical models support emergent classical behavior, what specific observables obey classical laws, and much more. For instance, in a recent work we elucidated that the limit under which Kirkwood-Dirac quasiprobability distributions become effectively classical coincides with the regime where the underlying physical model obeys the rules of Quantum Darwinism. In the present work, we study the breaking of Quantum Darwinism in a specific model and how that translates to non-classical measurement statistics. Interestingly, this provides effective tools for benchmarking the genuine quantum characteristics of NISQ hardware, which we demonstrate with IonQ's trapped-ion and IBM's superconducting quantum computing platforms.