Donut Physics
During January and February, we enjoyed very productive visits (and stays!) from Pedro Ribeiro (University of Lisbon) and Lucas Sá (University of Cambridge).
We discussed the first experimental detection of “Donuts”—the distribution of complex spacing ratios, CSRs, for various quantum channels (see the theoretical plots below). Depending on symmetry and (non)integrability, quantum channels can display CSR distributions of different shapes, classified as “cake” (integrable case) and “bitten donuts” (the depth of the byte depends on the particular symmetry the channel obeys).
Just before the New Year, Kristian Wold, PhD candidate & member of the Quantum Hub, ran series of experiments on two different quantum computers (in Finland and China), leading to a pleasant surprise: Donuts and cake were detected!
