Efficient variational quantum simulator incorporating active error minimisation

TL;DR

This paper introduces a variational quantum simulation method that actively minimizes errors by error boosting and extrapolation, making near-term quantum processors more effective for simulating quantum systems despite hardware imperfections.

Contribution

It presents a novel error mitigation technique combining error boosting and extrapolation within a variational framework for quantum simulation.

Findings

The method is more robust against error accumulation than traditional Trotterisation.

It is efficient for near-term quantum processors with modest size and imperfect control.

The approach enhances the feasibility of quantum simulations in the near future.

Abstract

One of the key applications for quantum computers will be the simulation of other quantum systems that arise in chemistry, materials science, etc, in order to accelerate the process of discovery. It is important to ask: Can this be achieved using near future quantum processors, of modest size and under imperfect control, or must it await the more distant era of large-scale fault-tolerant quantum computing? Here we propose a variational method involving closely integrated classical and quantum coprocessors. We presume that all operations in the quantum coprocessor are prone to error. The impact of such errors is minimised by boosting them artificially and then extrapolating to the zero-error case. In comparison to a more conventional optimised Trotterisation technique, we find that our protocol is efficient and appears to be fundamentally more robust against error accumulation.