Colloquia


Colloquia

We plan to return partly to in-person talks. These talks will be held in the interim lecture hall B 0.32 at MPQ and can additionally be attended online. Some talks remain online only.

2G regulations apply to in-person talks, i.e. every time you wish to participate in person, you will have to prove, e.g. with the CovPass-App, that you are vaccinated or recovered.Whether facemasks have to be worn inside the lecture hall will be communicated in the the e-mail announcement for each talk separately. In any case, you will need a medical facemask in the hallway. Audience not affiliated with MPQ are welcome to join in person as long as they meet 2G criteria.

Details on how to participate online are distributed via the mailing lists [wiss-mpq] and [Mpq-colloquium-stream]. To receive this information, please register using the adjacent link.

Scientific organization of the talks:  Dr. Stephan Dürr and Dr. Thomas Udem

In the thirties of the last century Pauli and Fermi had solved the apparent violation of conservation laws in nuclear beta-decay by introducing a so far undetected, weakly interacting, neutral, and practically mass less particle – the neutrino. Twenty years later Reines finally could detect this missing particle in beta-decay by experiment. The further exploration of neutrino properties and interactions revealed great discoveries and surprises: parity violation, the existence of three neutrino flavours, and finally, at the turn of the century, the oscillation between neutrino flavours by superposition of three mass eigenstates with tiny mass differences. But the question about the absolute neutrino mass is still open. The experimental part of the talk will focus on the neutrino mass searches based on terrestrial experiments within the KATRIN collaboration at Forschungszentrum Karlsruhe. [more]
New developments in far-field light microscopy made possible to radically overcome the diffraction limit (ca. 200 nm laterally, 600 nm along the optical axis) of conventional far field microscopy. Presently, three principal “nanoscopy” families have been formed: “Nanoscopy” based on highly focused laser beams; nanoscopy based on Structured Illumination Excitation (SIE); and nanoscopy allowing superresolution even in the case of homogeneous excitation. With such techniques, it has become possible to analyze the spatial distribution of fluorescent molecules on surfaces and in biostructures with a greatly increased light optical resolution down to a few nanometers, corresponding to 1/100 of the exciting wavelength, and with single target/molecule localization accuracies down to a few Angstrom. [more]
"Scientific News" (copied from: http://photon.physnet.uni-hamburg.de/de/ilp/sengstock/)"The research in our group mainly concentrates on two major topics. Experiments dedicated to the field of ultracold quantum gases are complemented by research activities in the field of fibre laser development and state-of-the-art ultra-sensitive spectroscopy.At temperatures close to absolute zero neutral atoms offer an ultimate degree of control over all system parameters. Bosonic, fermionic and mixed systems in trapping potentials of different geometry including e.g. optical lattices and hollow core photonic crystal fibres are realized in our group and offer the possibility to mimic pure quantum mechanical model systems over a wide range of interaction and correlation regimes.We are especially interested in laser cooling techniques, the physics of multi-component system pointing towards the investigation of e.g. quantum magnetism in frustrated geometries and other exotic quantum phases like e.g. composite particles made out of Bosons and Fermions in optical lattices.You will find descriptions of the individual research projects here." [more]
Quantum Metrology uses entanglement and other quantum resources to improve the sensitivity of interferometric measurements. Strongly-interacting light-matter systems, or "quantum interfaces", offer several routes to improvedsensitivity, including quantum non-demolition measurements, squeezing-enhanced optical readout of atomic sensors, and interaction-based measurements. I will describe recent experimental work that applies these quantum techniques in optical magnetometry, including sensitivity enhancements using optical entanglement, generation of squeezed states in magnetically-sensitive atomic ensembles, and interaction-based spin measurements that scale better than the so-called ''Heisenberg limit'' of measurement sensitivity. [more]
Strongly correlated few-body systems are the building blocks of nature, with atoms and nuclei being prominent examples. We have realized artificial few-body systems consisting of 1-10 atoms in a tightly confining trap inwhich all quantum mechanical degrees of freedom can be controlled. In spite of this extraordinary control these systems are isolated from the environment on the time scale of experiments (up to 60s). We thus have a generic model system that allows us to study few-body theories developed for example in nuclear physics with exceptional flexibility [1]. While a system of two strongly interacting particles can be solved analytically, this is no longer the case for three or more. In this way conceptually very simple systems can be studied experimentally, for which no theoretical prediction exists. [1] F. Serwane et al., Science 332, 336 (2011 [more]
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