Quantum Optics Group (LMU) - Quantum Many Body Systems Division (MPQ)

The challenge of the N² poster contest was to prepare a poster anybody can understand for visitors from many areas of expertise.
Frauke Seeßelberg won the first price with her poster on ultracold quantum matter on November 8th 2017.


To view her poster click here!

Many-body localization (MBL) is relatively well understood in one-dimensional systems. However, in two or more dimensions, its  nature is largely unknown and is strongly debated. In this experiment, we probe local relaxation in a two-dimensional quasi-periodic system and find that it becomes exceedingly large, hinting towards a 2D MBL phase. Our experiment provides access to regimes where controlled theoretical approaches are scarce and opens routes for stabilizing exotic phases of matter in two dimensions.

Phys. Rev. X 7, 041047

Shaken lattice systems have become a versatile tool to create novel band structures that exhibit topological properties and artificial magnetic fields for neutral atoms. However, especially interacting bosonic systems often suffer from strong heating. We have systematically studied the loss rates of an interacting BEC in a driven one-dimensional optical lattice and have identified the most dominant heating channels. Our findings suggest that heating might be strongly reduced in shaken three-dimensional lattice structures.

Phys. Rev. Lett. 119, 200402 (2017)

Science highlights research on ultracold matter in a special issue! We contributed a review on quantum simulations based on neutral atoms in optical lattice:

Science 357, 995 (2017) (DOI: 10.1126/science.aal3837)

In a recent set of experiments we observed hidden antiferromagnetic correlations in hole doped Hubbard chains. The hidden magnetic correlations are a manifestation of spin-charge separation, where the spin sector is not influenced by the density - the only effect of the randomly positioned holes it to mask the spin correlations. By measuring the position of every hole and spin we could reconstruct the underlying magnetic correlations.

Science 357, 484 (2017) (DOI: 10.1126/science.aam8990)

Press release: English, German

Explore the world of Quantum Mechanics

Open Lab Day - 4 July 2017
Quantum Many Body Systems Division - MPQ Garching

Are you considering doing your research thesis in experimental quantum physics?

• Learn about  state-of-the-art research in quantum gases
• Understand what a quantum simulator does
• Discuss with leading researchers and students
• Learn about precision lasers, ultrahigh vacuum, electronics and more
• See how it's done: visit our labs at MPQ!

Nobel Prize Winner Professor Wolfgang Ketterle from Massachusetts Institute of Technology MIT (Boston, USA), one of the pioneers of our field, is joining the LMU and MPQ from June 2017 to January 2018 as a winner of the Humboldt Research Award. This award is granted by the Alexander von Humboldt Foundation to outstanding academics from abroad in recognition of their scientific achievements. The award winner is invited to cooperate with leading scientists at a research institution in Germany on a long-term research project. During his stay Prof. Ketterle will be hosted by Prof. Immanuel Bloch and Prof. Theodor Hänsch.

Photo: David Ausserhofer, DFG

Christian Groß was awarded with the Heinz Maier-Leibnitz Prize 2017 of the German Research Foundation (DFG). This prestigious prize is awarded to early career researchers and Christian Groß received it for his experimental studies of quantum many-body systems using quantum gas microscopes.

MPQ Press Release

Isolated quantum systems may fail to thermalize in the presence of disorder, a phenomenon known as Many-Body Localization (MBL). Should the system, however, be in contact with a bath, as is present in all realistic expriments, thermalization is unavoidable. We develop a novel technique for introducing a controlled bath to cold-gases systems by scattering near-resonant photons and study its effects on MBL. Close to the MBL transition, we find that the susceptibility to the bath is strongly enhanced by interactions.

Phys. Rev. X 7, 011034 (2017)

Photo: Christoph Hohmann, Nanosystems Initiative Munich (NIM)

Most matter would get mixed upon shaking. However, Many-Body Localized systems are peculiar, and even while periodically shaken, may not get mixed. We create and experimentally demonstrate that this is indeed the case, and that order can exist in periodically driven matter. Further, we find a novel and unexpected regime which is exceedingly stable under periodic driving and whose full theoretical understanding remains an outstanding challenge.

Nature Physics, DOI:10.1038/nphys4020

Press release: English