Talks, Colloquia

17:00 Uhr KIP, INF 227, Otto-Haxel-Hörsaal
Prof. Anthony Leggett College of Engineering, University of Illinois at Urbana-Champaign

Bell's theorem, entanglement, quantum teleportation and all that

One of the most surprising aspects of quantum mechanics is that under certain circumstances it does not allow individual physical systems, even when isolated, to possess properties in their own right. This feature, first clearly appreciated by John Bell in 1964, has in the last three decades been tested experimentally and found (in most people's opinion) to be spectacularly confirmed. More recently, it has been realized that it permits various operations which are classically impossible, such as "teleportation" and secure-in-principle cryptography. This talk is a very basic introduction to the subject, which requires only elementary quantum mechanics; it is primarily aimed at senior undergraduates or beginning graduate students, but has on occasion been given with apparent success as a departmental colloquium.

17:00 Uhr Neues Physikalisches Institut INF 226, Konferenzraum 1-3 (Room 00.101 bis 00.103)
Dr. Carsten Niebuhr DESY Hamburg

Belle II

17:00 Uhr Kirchhoff-Institut, INF 227 SR 1.403, SR 1.403
Prof. Dr. Peter Hänggi Institut für Physik, Universität Augsburg

On the use and abuse of *thermodynamic* entropy

16:15 Uhr Philosophenweg 12, Großer Hörsaal
Pieter van Dokkum Yale University

Dragonflies, dark matter, and the hunt for ghostly galaxies

The talk will highlight the latest results on "ultra diffuse" galaxies, ghostly objects that are as large as the Milky Way but 100x-1000x fainter. They were discovered with the Dragonfly Telephoto Array, a little telescope that we built in New Mexico, and they look different from all other known classes of galaxies. Follow-up work with the Keck telescope and the Hubble Space Telescope has revealed that what we can't see of the galaxies is even stranger: their dark matter does not "play by the rules" but seems to be present in large amounts for some and too little for others. The talk will discuss these developments, and also look forward to what we hope to learn in the future.