Group seminar at MPQ and Zoom: Probing & benchmarking of many-body quantum devices with random(ized) measurements

Andreas Elben, Caltech, California, USA
Group seminar at MPQ lecture hall and Zoom
Tuesday, February 6 at 09:00am (MEZ)

Abstract: In the era of noisy intermediate-scale quantum devices, a key challenge is to scale up these devices while enhancing the control and quality of their individual components. This necessitates efficient protocols for probing and benchmarking quantum devices at scale. In my talk, I will focus on the use of both engineered and emergent randomness in quantum systems for probing and benchmarking. First, I will introduce randomized measurements - measuring quantum states repeatedly in randomly chosen bases - as a widely applicable toolbox for characterizing quantum many-body devices and probing associated phenomena. Specifically, I will present experimental results demonstrating robust estimation of the quantum Fisher information in superconducting qubit experiments. Secondly, I will discuss how randomness, manifest as universal pure state ensembles, naturally emerges in ergodic quantum dynamics. This gives rise to benchmarking protocols through fidelity estimation for highly entangled quantum states. I present experimental results in a 60-atom Rydberg quantum simulator beyond exact classical simulatability.