Entanglement-assisted quantum speedup: Beating local quantum speed limits

TL;DR

This paper derives fundamental speed limits in quantum systems, showing how entanglement can enable exponential speedups over classical and non-entangled quantum dynamics, with practical implications for quantum information processing.

Contribution

It introduces new bounds on quantum speedup leveraging entanglement, applicable to various quantum systems, and demonstrates their tightness and scalability.

Findings

Entanglement enables exponential quantum speedup.

Derived bounds are tight and scalable with system size.

Applicable to bipartite, multipartite, and open quantum systems.

Abstract

Research in quantum information science aims to surpass the scaling limitations of classical information processing. From a physicist's perspective, performance improvement involves a physical speedup in the quantum domain, achieved by dynamically exploiting quantum correlations. In this study, speed limits in interacting quantum systems are derived by comparing the rates of change in actual quantum dynamics with the quasi-classical evolution confined to the manifold of non-entangled separable states. The utility of the resulting bounds on entanglement-assisted speedup is demonstrated on bipartite qubit systems, bipartite qudit systems, as well as a complex multimode systems. Specifically, the proposed speed limits provide a tight bound on quantum speed advantage, including a quantum gain that can scale exponentially with the system's size. Extensions of the results to open systems and measurable witnesses are discussed.