Simulating quantum many-body dynamics on a current digital quantum computer

Adam Smith,Johannes Knolle,Frank Pollmann,M S Kim

doi:10.1038/s41534-019-0217-0

Adam Smith, Johannes Knolle + Show 2 more

Open Access

https://doi.org/10.1038/s41534-019-0217-0

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Abstract

Universal quantum computers are potentially an ideal setting for simulating many-body quantum dynamics that is out of reach for classical digital computers. We use state-of-the-art IBM quantum computers to study paradigmatic examples of condensed matter physics—we simulate the effects of disorder and interactions on quantum particle transport, as well as correlation and entanglement spreading. Our benchmark results show that the quality of the current machines is below what is necessary for quantitatively accurate continuous-time dynamics of observables and reachable system sizes are small comparable to exact diagonalization. Despite this, we are successfully able to demonstrate clear qualitative behaviour associated with localization physics and many-body interaction effects.

Highlights

Quantum computers are general purpose devices that leverage quantum mechanical behaviour to outperform their classical counterparts by reducing the computational time and/or the required physical resources.[1]
Considering the limited system sizes and time scales that we can reach; it highlights the current limitations of these quantum devices
We are still able to access a range of qualitative physical behaviours demonstrating non-trivial simulations of quantum dynamics

Summary

Introduction

Quantum computers are general purpose devices that leverage quantum mechanical behaviour to outperform their classical counterparts by reducing the computational time and/or the required physical resources.[1] Excitement about quantum computation was initially fuelled by the prime-factorization algorithm developed by Shor,[2] which is most popularly associated with the ability to attack currently used cyber security protocols. It provided a paradigmatic example of dramatic exponential improvement in computational speed when compared with classical algorithms. The apparent proximity of current devices to this milestone makes it timely to review the current capabilities and limitations of quantum computers

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