Das physikalische Kolloquium der Universität Göttingen und das Institut für Materialphysik laden ein zur Verleihung der Goldenen Promotionsurkunde an Herrn Prof. Dr. Richard Wagner.
Gastredner: Prof. Dr. Ludwig Schultz (TU Dresden)
Vortrag des Ehrengastes: „Zeitreise durch 50 Jahre Physik: Von Göttingen über Oxford, Pittsburgh, Geesthacht, Jülich nach Grenoble“
The past three decades of exoplanet discovery have revealed a bewildering diversity of planetary systems, as well as tantalizing correlations between their features and other properties such as the mass of the host stars. To understand the origin of these patterns, we must study the emergence of planets from circumstellar disks of gas and dust, and the prior evolution of those disks. These too exhibit remarkable differences in structure, evolution, and lifetime which are poorly understood. The dissipation of disks under the influence of high-energy emission from the central star is considered important; I show how the interaction of the partially ionized disk with the stellar magnetic field will modulate that emission and can explain observations. This suggests that the outcome of planet formation is significantly influenced by the large-scale magnetic field of the star, among other variables. Future observations by ground- and space-telescopes of the fields of very young stars, the structures and compositions of their disks, and the planets that form from them will more fully explore this connection. In a real way, the ancient Sun’s magnetic field could be one reason these words are written on a world that orbits it.
Accessing theoretically the ground state of interacting quantum matter is a long-standing challenge, especially for complex two-dimensional systems. Recent developments have highlighted the potential to solve the quantum many-body problem by means of so-called neural quantum states. The enabling idea of this approach is to harness the power of machine learning by encoding the many-body wave function into an artificial neural network. In this talk, I will aim at introducing the main idea and central developments of this computational approach. In particular, I will outline one of the critical limitations, which until recently has prohibited the training of modern large-scale deep network architectures. I will show how this key limitation has been now resolved through the so-called minimum-step stochastic reconfiguration method. I will demonstrate for paradigmatic frustrated quantum magnets that this enables the neural quantum states method to reach regimes and accuracies beyond what is accessible by other computational approaches. Further, I will highlight the recent results on solving the real-time dynamics of correlated quantum matter, which has allowed us to verify for instance for the first time the quantum Kibble-Zurek mechanism for interacting quantum many-body systems in two spatial dimensions.
Since the formation of atomic Bose-Einstein condensates (BEC) nearly 30 years ago, systems of cold atoms have developed into a versatile playground for the investigation into quantum many-body physics, with the promise to shed light onto dynamical processes in the spirit of quantum simulation efforts. With exquisite parameter control and a broad range of detection methods, a multitude of phenomena, ranging from superfluidity and quantum phase transitions to supersolidity and quantum transport, can be probed with high precision. I will give a broad introduction to the field of cold atoms and its techniques, highlighting a few of the milestone results of the past, and then turn to a selected set of recent experiments that address various dynamical quantum many-body processes such as dynamical localization, and the breaking thereof, and anyonization of bosons.
