EPJ Quantum Technol. (2014) 1: 10
https://doi.org/10.1140/epjqt10

Review

What is a quantum simulator?

¹ Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore, 117543, Singapore
² Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
³ Keble College, University of Oxford, Parks Road, Oxford, OX1 3PG, UK
⁴ Institute for Scientific Interchange, Via Alassio 11/c, Torino, 10126, Italy

^* e-mail: tomi.johnson@physics.ox.ac.uk

Received: 12 May 2014
Accepted: 1 July 2014
Published online: 23 July 2014

Abstract

Quantum simulators are devices that actively use quantum effects to answer questions about model systems and, through them, real systems. In this review we expand on this definition by answering several fundamental questions about the nature and use of quantum simulators. Our answers address two important areas. First, the difference between an operation termed simulation and another termed computation. This distinction is related to the purpose of an operation, as well as our confidence in and expectation of its accuracy. Second, the threshold between quantum and classical simulations. Throughout, we provide a perspective on the achievements and directions of the field of quantum simulation.

PACS Codes: 03.65.-w, 03.67.Ac, 03.67.Lx.