Condensed Matter Seminar

Friday 23 November 2018, 3:00pm to 4:00pm

Venue

Physics C36 - View Map

Open to

Applicants, Postgraduates, Prospective Students, Staff, Undergraduates

Registration

Registration not required - just turn up

Event Details

Efficiently measuring and tuning quantum devices using machine learning

Abstract: Fulfilling the promise of quantum technologies requires to be able to measure and tune several devices; fault-tolerant factorization using a surface code will require 10^8 physical qubits. A long-term approach, based on the success of integrated circuits, is to use electron spins in semiconducting devices. A major obstacle to creating large circuits in this platform is device variability. It is very time consuming to fully characterize and tune each of these devices and this task will rapidly become intractable for humans without the aid of automation.

I will present efficient measurements on a single quantum dot device based on a lateral quantum performed by a machine learning algorithm. This algorithm dot. The current through the device employs a probabilistic deep-generative model, capable of generating multiple full-resolution reconstructions from scattered partial measurements. Information theory is then used to select the most informative measurements to perform next. The algorithm outperforms standard grid scan techniques in different measurement configurations, reducing the number of measurements required by up to 4 times. I will also show the use of Bayesian optimisation to tune a single quantum dot device. By generating a score function, we can make the algorithm find the operating regime of a device. We tune the device to the single-electron tunnelling regime searching in a high-dimensionality parameter space in less than a thousandth part of the time that it requires manually.

Speaker

Dr Natalia Ares University of Oxford

Contact Details

Name Dr Sergey Kafanov
Email

sergey.kafanov@lancaster.ac.uk