Real- and imaginary-time evolution with compressed quantum circuits

TL;DR

This paper demonstrates that optimized quantum circuits can efficiently simulate real- and imaginary-time evolution of quantum many-body systems, outperforming classical methods and feasible on near-term quantum hardware.

Contribution

It introduces a quantum algorithm for real- and imaginary-time evolution that is optimized for near-term quantum computers and benchmarks its effectiveness on the transverse field Ising model.

Findings

Quantum circuits outperform classical numerics in simulating non-equilibrium quantum dynamics.

The proposed algorithms successfully find ground states and simulate real-time evolution.

Implementation on quantum hardware shows effective capture of quantum dynamics.

Abstract

The current generation of noisy intermediate scale quantum computers introduces new opportunities to study quantum many-body systems. In this paper, we show that quantum circuits can provide a dramatically more efficient representation than current classical numerics of the quantum states generated under non-equilibrium quantum dynamics. For quantum circuits, we perform both real- and imaginary-time evolution using an optimization algorithm that is feasible on near-term quantum computers. We benchmark the algorithms by finding the ground state and simulating a global quench of the transverse field Ising model with a longitudinal field on a classical computer. Furthermore, we implement (classically optimized) gates on a quantum processing unit and demonstrate that our algorithm effectively captures real time evolution.