Recent Outreach Activities
University Awards longlist and WATE PGR shortlist
Congratulations to the members of the department who have been nominated for individual and team University Awards, and the postgraduates nominated for WATE (PGR).
Physics nominees include Duncan Brealey, Rosalind Johnstone, Monica Ciomaga Hatnean, James Gott, Richard Henshaw, and a number of teams.
Leakage in IBM's quantum computer
Quantum computing is entering a new era of remotely-accessible quantum machines and, given their recent development, computation is more than likely accompanied by errors. One such error—quantum leakage—is an often-overlooked imperfection that amounts to quantum information escaping from the desired computational space and whose presence is rarely identified by a remote user. In work published in Physical Review A (DOI:https://doi.org/10.1103/PhysRevA.99.032328) Armands (who began this work as a part of his MPhys project), Animesh, and George adapt one of dimension witness protocols designed for the purpose of a remote discovery of leakage and equip it with statistically robust, user-defined confidence levels before applying to a remotely accessed quantum processor. They find a circuit component "transmon" acting in a higher computational space than advertised.
Their study constitutes the first, model-independent experimental discovery of leakage in a remotely-accessed quantum computer. They have achieved this by a substantive theoretical development of the method of delays, originally adopted from classical chaos theory and proposed for quantum systems in a path-breaking paper almost a decade ago.
Such finding confirms the imperfection of current quantum computers, but at the same, guides the engineers to small step improvements that would eventually lead to the ultimate goal of fault-tolerant quantum computation.
Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets
A study of chiral liquid-crystal droplets shows how defects lead to geometric arrangements similar to atoms in a molecule, and provides a new framework for analysing novel chiral materials.