2023 Joseph Thomson Medal and Prize
Professor Ulrich Schneider for groundbreaking experiments on the collective dynamics of quantum gases in optical lattices, including fundamental studies of localization effects in both disordered and quasicrystalline systems.
Over the last decade, ultracold atomic gases have emerged as excellent experimental platforms for fundamental studies of out-of-equilibrium many-body quantum phenomena, thanks to the unique possibilities they provide to engineer the atom-trapping potentials, dynamically tune the interparticle interactions, and observe the resulting complex dynamics in real time. Professor Ulrich Schneider has played a leading role in this worldwide effort. His wide-ranging contributions include: studies of topological effects in atom transport; realisation of negative absolute temperature for motional degrees of freedom; studies of the dynamics of both continuous and discontinuous quantum phase transitions; and a series of groundbreaking experiments on localization effects in both disordered systems and quasicrystals.
His pioneering demonstration of many-body localisation in an interacting disordered gas has confirmed a long-standing theoretical prediction and opened a whole new field of research, providing a powerful way to study experimentally the subtle interplay between quantum interference and interparticle interactions. This first demonstration, in 2015, has already stimulated numerous follow-up experiments and more than 1000 theoretical papers. In his own work, Schneider has performed further milestone experiments on coupled localised systems and localisation in open quantum systems.
While the large international community has been focusing its attention on many-body localisation in disordered systems, Schneider has recently taken this research in an entirely new direction by constructing the world’s first optical quasicrystal for trapping of ultracold atomic gases. Since a quasicrystal is long-range ordered but not periodic, his experiments probe a fascinating middle ground between order and disorder, and open the door to many fundamental studies of atomic transport in both non-interacting and interacting quantum gases. Recently, Schneider has demonstrated localization in the non-interacting case, while the controllable introduction of interatomic interactions is now allowing unprecedented studies of the elusive Bose glass state.
Beyond his own experiments at the University of Cambridge, Schneider has been playing pivotal roles in several large national projects, including the UK-wide collaboration on fundamental studies of out-of-equilibrium many-body physics, the UK National Quantum Technologies Programme, and the Atom Interferometer Observatory and Network programme on using atomic gases to search for ultralight dark matter and explore gravitational waves in a so-far inaccessible frequency range.
Through the groundbreaking outputs from his research group, and his significant support for these important national programmes, Schneider adds enormously to the strength of the UK in the development and application of new quantum technologies.