Imaginary Time Propagation on a Quantum Chip

TL;DR

This paper introduces an algorithm for implementing imaginary time propagation on quantum computers, enabling the simulation of ground states in quantum many-body systems on near-term devices.

Contribution

It proposes a novel algorithm that adapts imaginary time evolution for quantum hardware, facilitating quantum simulations of complex systems.

Findings

Algorithm successfully applied to simple problems on digital quantum machines.

Paves the way for quantum simulation of ground states in microscopic systems.

Enables porting classical imaginary-time methods to quantum devices.

Abstract

Evolution in imaginary time is a prominent technique for finding the ground state of quantum many-body systems, and the heart of a number of numerical methods that have been used with great success in quantum chemistry, condensed matter and nuclear physics. We propose an algorithm to implement imaginary time propagation on a quantum computer. Our algorithm is devised in the context of an efficient encoding into an optimized gate, drawing on the underlying characteristics of the quantum device, of a unitary operation in an extended Hilbert space. However, we proved that for simple problems it can be successfully applied to standard digital quantum machines. This work paves the way for porting quantum many-body methods based on imaginary-time propagation to near-term quantum devices, enabling the future quantum simulation of the ground states of a broad class of microscopic systems.