Error Management for a Quantum Chemistry Applicaiton on a Near-Term Quantum Computer

Quantum computing devices are developing at a rapid pace with error rates that are on the cusp of early fault tolerance. The promise that quantum computing offers for quantum applications, such as large scale simulations of quantum chemistry and physics, is exponential speed up with enough accuracy to predict outcomes of experiments in the real world. Delivering on the promise of high accuracy and precision requires methods to evaluate the computational accuracy of the quantum computing devices. We develop a framework to estimate the computational accuracy of near-term noisy intermediate scale quantum computing (NISQ) devices using a quantum chemistry application. We use device agnostic error-mitigation schemes, quantum error detection (QED) and read out error detection, with post-selection, to mitigate the dominant sources of noise. We demonstrate the framework on the Quantinuum H1-1E emulator by simulating the ground state of molecular hydrogen, estimating the energy, and calculating the precision of the estimate with the default error model of the H1-1 emulator that mimics the noise profile of the H1-1 device. We show that compared to the unencoded simulation, the encoded simulation results in a lower energy estimate by more than 1 mHa with comparable precision. Additionally, unlike the best estimate from unencoded simulations, the results from the encoded simulation also fall within the chemical accuracy threshold of 1.6mHa from the exact energy.