Local robust shadows on a trapped ion computer -- a case study

TL;DR

This paper demonstrates a local robust shadow protocol on a trapped-ion quantum computer that mitigates measurement errors, enabling faster experiments with increased error rates.

Contribution

The paper introduces a local robust shadow protocol with Pauli-X-twirling for error mitigation in trapped-ion quantum measurements, validated on various quantum states.

Findings

The protocol effectively mitigates errors from shortened measurement pulses.

It successfully benchmarks different quantum states with improved measurement accuracy.

Faster quantum experiments are enabled despite increased error rates.

Abstract

We experimentally demonstrate local robust shadows on a trapped-ion quantum computing system, a protocol developed to counteract measurement errors. We alternate between a calibration stage and the shadow estimation stage and also introduce Pauli-X-twirling before measurements in both stages to symmetrize error rates. We then demonstrate the protocol on a trapped-ion quantum computer with artificially shortened measurement pulse duration. This yields faster experiments at the cost of increased error rates which are subsequently mitigated by the robust shadow protocol. We benchmark this approach on three exemplary quantum states: a local Haar random state, as well as standard and Pauli-correlation-encoded QAOA states. In all three cases, the local robust shadow protocol succeeds at mitigating the increased error rates hailing from shorter measurement pulse durations.