Seminar: Randomised benchmarking for non-Markovian noise

2021. 13/8 FridayTime: Aug 13, 10:00 – 11:00 (Taipei Time)
Speaker: Pedro Figueroa Romero (Hon Hai Research Institute)
Title: Randomised benchmarking for non-Markovian noise
In the far-reaching goal of reaching fault tolerance in quantum computers, setting a benchmark for the diverse types of noise that can arise in realistic quantum computations constitutes one of the first steps. In the last decade, the randomised benchmarking (RB) protocol has become the gold standard for estimating average error rates of a given gate-set with little resources. The elephant in the room, for quantum noise benchmarking and benchmarking, however, is the presence of temporal correlations, or so-called non-Markovianity. State-of-the-art RB protocols can estimate average noise for very general gate-sets and diverse aims, normally predicting error rates that decay as a linear combination of exponentials in the number of gates of a computation. Deviations from an exponential decay behaviour are generally assumed to belong to the realm of non-Markovian (temporally-correlated) noise, which has largely been unexplored theoretically in the context of quantum errors.

In our work, we employed a recently developed framework for non-Markovian quantum phenomena to derive an analytical expression for the average sequence fidelity —a figure of merit containing the error rates of an RB sequence— for an RB experiment with non-Markovian noise. We did this as a first approach for the Clifford group, which can be realised efficiently on a quantum processor. Consequently, we proposed a set of methods, implementable with current experimental setups, to quantitatively estimate the effects of non-Markovianity in RB, the time-scales of the memory of non-Markovian noise and to diagnose the (in)coherence of non-Markovian noise, demonstrating all of these with two proof-of-principle examples.
Reference: arXiv:2107.05403
Dr. Pedro Figueroa Romero received his Ph.D. degree from School of Physics & Astronomy, Monash University, Australia. He was a former member in Monash Quantum Information Science (MonQIS) group and now is a member in Quantum Group, Hon-Hai Research Institute.
Pedro Figueroa-Romero – Postdoctoral Research Associate – Foxconn | LinkedIn