Can we trust the outputs of a noisy quantum computer?

Friday, August 23, 2019 10:00 am - 10:00 am EDT (GMT -04:00)

Sam Ferracin, University of Warwick

Noisy Intermediate-Scale Quantum (NISQ) computing devices promise to have computing capabilities that exceed those of modern supercomputers. As these devices will be afflicted by non-negligible levels of noise, understanding if their outputs can be trusted is a task of timely importance. While several protocols have been devised to accomplish this task, in this talk I will focus on trap-based protocols, a class of protocols that check the correct functionality of a quantum computer by employing classically efficiently simulable computations (the \trap" computations). I will begin with an overview of resource-efficient trap-based protocols for veriable blind quantum computing [1], which (under minimal assumptions) can reject incorrect outputs even in the presence of malicious noise. I will then compare these protocols with our newly developed accreditation protocol [2], which provides an upper-bound on the variation distance between noisy and noiseless probability distributions of the outputs of the target computation. Finally, I will highlight the main challenges and open questions regarding trap-based protocols.

[1] Ferracin, Kapourniotis, Datta, Reducing resources for verication of quantum computations, Phys. Rev. A 98.022323 (2017).
[2] Ferracin, Kapourniotis, Datta, Accrediting outputs of noisy intermediate-scale quantum computing devices, arXiv:1811.09709 (2018).