64-Qubit Quantum Circuit Simulation

TL;DR

This paper introduces a new classical simulation scheme for quantum circuits that efficiently handles more qubits and depth, enabling large-scale simulations with less hardware and high parallelizability.

Contribution

The authors present a novel simulation method that significantly extends the number of qubits and circuit depth achievable on standard hardware, surpassing previous limitations.

Findings

Simulated a 64-qubit, depth 22 circuit on a 128-node cluster.

Achieved 56- and 42-qubit simulations on a single PC.

Estimated 72-qubit, depth 23 simulation in about 16 hours on a supercomputer.

Abstract

Classical simulations of quantum circuits are limited in both space and time when the qubit count is above 50, the realm where quantum supremacy reigns. However, recently, for the low depth circuit with more than 50 qubits, there are several methods of simulation proposed by teams at Google and IBM. Here, we present a scheme of simulation which can extract a large amount of measurement outcomes within a short time, achieving a 64-qubit simulation of a universal random circuit of depth 22 using a 128-node cluster, and 56- and 42-qubit circuits on a single PC. We also estimate that a 72-qubit circuit of depth 23 can be simulated in about 16 h on a supercomputer identical to that used by the IBM team. Moreover, the simulation processes are exceedingly separable, hence parallelizable, involving just a few inter-process communications. Our work enables simulating more qubits with less hardware burden and provides a new perspective for classical simulations.