Kolloquien

Festkolloquium zum 90. Geburtstag von Prof. Dr. Gisbert zu Putlitz   mehr...

Symmetries have played a crucial role in the development of the standard model of particle physics. Moreover, they are believed to provide the key ingredients for a unified description of all fundamental interactions. We review the arguments that favor the investigation of these mathematical structures and explain possible consequences for particle physics and cosmology.   mehr...

Man-made organic materials allow to tailor functional device properties in an unprecedented manner. A prerequisite is the fundamental understanding of the underlying physics. In this seminar, I will introduce some of our recent work, in which we investigate the fundamentals of charge motion in carbon-based molecular materials and use the gained insights to develop novel electronic functionality.   mehr...

We study the force-force correlator for disordered elastic systems. We show that each of the relevant universality classes has its own function. The nicest experiments are for DNA unzipping and Barkhausen noise. For the latter we observe two distinct universality classes, depending on the range of spin interactions. In all cases force- force correlations grow linearly at small distances, while they are bounded at large distances. As a consequence, avalanches are anti-correlated, i.e. reduced in size, at short distances.   mehr...

High field magnet applications like MRI, NMR and accelerator magnets are one of the major success stories of superconductivity and only possible by tailoring superconducting materials on various length scales. Besides the conventional low temperature superconductors, cuprate based High Temperature Superconductors (HTSC) and new superconducting materials will open completely new opportunities in modern magnet/power applications and are currently on the way into commercial products.   mehr...

Finding new land expands the horizon. The same is true for new phases of matter. I will discuss the rich landscape of strongly correlated quantum materials and their fascinating properties, using heavy fermion compounds as a particularly versatile platform to explore them.   mehr...

Since the inception of agriculture by mankind about ten millennia ago, the basis of the food supply for the human population has been the farming of field crops. However, our conventional, biogenic agriculture (CBA) has failed to provide a reliable concept to feed a growing population in a sustainable way. In particular CBA suffers from severe environmental externalities - such as the massive use of land area, water for irrigation, fertiliser, pesticides, herbicides, and fossil fuel.   mehr...

In the scientific reports, political debates, and to a large degree also in the media, the measure of global climate change around the world is global mean temperature rise used as the metric to determine how humans are changing the climate by burning fossil fuels. It is, however, not the abstract measure of global mean temperature that cause loss and damage from climate change, instead the impacts of climate change primarily manifest through rising sea levels and the changing risks of extreme weather events.   mehr...

In 2015 the LIGO detectors observed, for the first time, a gravitational wave passing through the Earth produced by the collision of two black holes. Such an event was a milestone for astrophysics and it provided a remarkable confirmation of the general theory of relativity. Since then, as many as ninety gravitational waves have been observed by the LIGO and Virgo experiments, including signals from binary neutron stars and neutron- star - black-hole binaries.   mehr...

Nuclear halos are a fascinating manifestation of quantum physics. They belong to a subset of low-density clustering for which most of the probability to find the halo nucleon extends to a region of space that is classically forbidden. Their properties show universal aspects of few-body systems such as scaling laws. Advances in the production of radioactive isotope beams give access to loosely-bound neutron-rich systems at the nuclear driplines, where halos are found.   mehr...

In the 1980s, Feynman observed that many-body quantum problems seemed difficult to solve with classical computers due to the exponentially growing size of the quantum state Hilbert space. He proposed that a quantum computer would be a natural solution.   mehr...

Aerosols, tiny solid particles or liquid droplets suspended in air, are key elements in the atmosphere of the Earth system, influencing air quality, climate and human health in the Anthropocene. They scatter or absorb sunlight, serve as nuclei for clouds and precipitation, and adversely affect human health. Aerosol formation and evolution involve detailed gas-phase atmospheric chemistry and gas-particle interactions. The interaction of aerosols with atmospheric water, as well as their size and physical properties, are key to much of their behavior.   mehr...

Ever noticed that annoying lag that sometimes happens during the internet streaming from, say, your favorite football game? Called latency, this brief delay between a camera capturing an event and the event being shown to viewers is surely annoying during the decisive goal at a World Cup final. But it could be deadly for a passenger of a self-driving car that detects an object on the road ahead and sends images to the cloud for processing. A way to dramatically reduce latency in artificial intelligence (AI) systems lies in using light for computation instead of electronic circuits.   mehr...

Computer vision is the branch of computer science devoted to the analysis and understanding of images by computer algorithms. Typical problems studied in this field and visited also in this talk are image segmentation, object recognition and multiple object tracking. Rooted in engineering, an emphasis of computer vision research is on the empirical study of practical algorithms. Trained as a physicist, I, the speaker, have always been interested also in principles and models foundational to image analysis.   mehr...