Southwest Quantum Information and Technology

Mitigating errors in quantum simulation problems through additional measurements

Presenting Author: Jarrod McClean, Google

One of the promising early applications for pre-fault-tolerant quantum computers is the simulation of quantum systems, including the electronic structure problem for quantum chemistry. We recently introduced the quantum subspace expansion (QSE) as a means to extend near-term variational methods to excited states without the need for additional coherence time in the quantum device. It relies only upon additional quantum measurements of a prepared input state and the solution of a polynomially sized generalized eigenvalue problem on a classical computer. In addition, this method was also predicted to mitigate certain incoherent errors in the presence of noise on real quantum devices. This prediction has recently been experimentally verified on superconducting quantum devices. Here we review these results in the context of upcoming near-term experiments and expand the theoretical foundations for the conditions under which error mitigation or correction is expected when using this technique.

Read this article online: https://arxiv.org/pdf/1603.05681.pdf, https://arxiv.org/abs/1707.06408

(Session 5 : Thursday from 5:00pm - 7:00 pm)