Quantum Memories and Schroedinger’s Cat

Wednesday 1 June 2022 (4-5pm, Carslaw Lecture Theatre 275)

Speaker: Professor Stephen Bartlett (School of Physics, University of Sydney)

Title: Quantum Memories and Schrödinger’s Cat

Abstract: Quantum information is very fragile, but clever quantum engineers aspire to use error correction to keep information intact. Topologically ordered phases—wherein the most exotic properties of quantum physics such as entanglement are protected within a strongly-interacting material—are currently being commandeered as quantum error-correcting codes for today’s quantum architectures. I will introduce these as well as a new generation of theoretical materials that promise to self-correct themselves. Much like a real-world example of Schrödinger’s Cat, a self-correcting quantum memory can protect quantum information in a thermal environment for an arbitrarily long time, without the need for active error correction. I will demonstrate that symmetry can assist in giving self-correction in 3D spin lattice models. In particular, I will present quantum codes corresponding to a 2D symmetry-enriched topological (SET) phase that appears naturally on the boundary of an exotic 3D symmetry-protected topological (SPT) phase.

About the speaker: Stephen Bartlett is a theoretical quantum physicist and Professor in the School of Physics, the University of Sydney. He leads a team pursuing both fundamental and applied research in quantum information theory, including the theory of quantum computing. He is a Chief Investigator in the Australian Research Council Centre of Excellence in Engineered Quantum Systems (EQUS), where he leads a research program on Designer Quantum Materials. He is the inaugural Lead Editor of the APS journal PRX Quantum.

Tea before talk: Please join for afternoon tea at 3:30 – 4:00 pm in 7th Floor Tea Room, Carslaw Building.