Program winter term 2017/2018
Monday, October 16, 2017, 4:15pm, Hörsaal 28 D 001
Dr. Felix Kahlhoefer (RWTH Aachen University)
Fantastic WIMPs and Where to Find Them
Abstract:
The overwhelming evidence that the dominant form of matter in the Universe is fundamentally different from any visible matter demonstrates the limitations of our current understanding of particle physics. At the same time, it provides a compelling argument for expecting new physics to be discovered in the near future. In this colloquium, I will review the global effort to search for this so-called dark matter, pursued by a wide range of different experiments. I will argue that solving the dark matter puzzle requires input from many complementary observations and discuss how all this information can be combined using the most recent developments in analysis tools and global fitting frameworks.
Monday, November 6, 2017, 4:15pm, Hörsaal 28 D 001
Dr. Oana Cojocaru-Miredin (RWTH Aachen University)
Designing novel solar devices via understanding the link between structure, chemistry, and performance at the nanoscale
Abstract:
Solar energy, which is the Earth's major renewable energy resource, is one of the reliable source of "green electricity". The conversion of the sunlight into electricity is done using solar cells. A key parameter which describe the quality of a solar cell is the efficiency (how many percentage of sunlight is converted into electricity). However, the impact of the physical phenomenon taking place at the nanoscale on the efficiency had only been vaguely studied in literature.
Therefore, in this colloquium I will show a possible viable strategy in improving the cell performance first by understanding the limiting factors in terms of electrical, structural, and chemical properties at the nanoscale and second by applying these novel R&D findings in designing better solar devices.
Monday, November 20, 2017, 4:15pm, Hörsaal 28 D 001
Prof. em. Dr. Herwig Schopper (Universität Hamburg)
SESAME - a synchrotron radiation laboratory in Jordan and "science for peace"
Abstract:
A dream became reality by the creation of an international laboratory in the MENA region under the auspices of UNESCO following the CERN model with the objectives of promoting science and technology but also bringing nations together. The political, legal and technical pitfalls will be described. Decisions are not taken always on rational grounds but chance and the interventions of some personalities were significant as will be exemplified by some stories. Now government officials and scientists from countries with political frictions work together peacefully. Thus science benefits from politics but also the reverse is true. The facility was inaugurated in May 2017. A user community has been established and first experiments start to work. A new initiative following the SESAME example has been initiated very recently for the Balkan.
Host:
Achim Stahl
Monday, December 4, 2017, 4:15pm, Hörsaal 28 D 001
Prof. Dr. Alexander Grossmann (HTWK Leipzig)
New Perspectives in Scientific Publishing
Abstract:
How will scientific publishing develop in the 21st century? Over the last decades topics such as Journal Impact Factor, blind peer-review and library subscriptions have dominated the discussion. However the digital revolution has already begun to change the rules. New topics such as “article- level-metrics”, “post-publication peer review” and “open data” have emerged and every single day four new Open Access journals are founded. Open Access is becoming publicly mandated in the US and EU, encouraging researchers to submit their work to open repositories. Preprint servers and subject repositories such as arXiv or bioRxiv have been entering the market to provide faster access to unpublished results. Open peer review is practiced by ever more journals and consortia. Post- Publication Peer Review is a new buzz word to use crowd-sourcing to evaluate scientific research. Publication of research results is at the center of the scientific enterprise. It is therefore essential not only for young scientists to have a good overview of the changing publishing landscape. This seminar explores the ways in which the speed and network character of the internet breaks down old categories of scholarly publishing and creates new ways of communicating scientific results.
Host:
Markus Morgenstern
Monday, December 18, 2017, 4:15pm, Hörsaal 28 D 001
Prof. Dr. Reinhart Poprawe (RWTH Aachen University)
Physics in Tailored Light – The future of Laser Technology
Abstract:
Laser applications have been developed for the benefit of our society very successfully over the last decades. The advances reach from “Digital Photonic Production” in modern manufacturing of Industry 4.0 to measurement technology, medical devices and processes to nano- and bio-applications on the molecular level, all the way to new advances and results in fundamental science such as gravitational waves and attosecond research.
The presentation will cover the role and relevance of physics and natural sciences in this context. The strong correlation of fundamental and application oriented research with innovations leading to global competitiveness as well as general benefit for the societies is shown in a set of examples. Focus will be put on Aachen world-record kW-class fs-lasers, additive manufacturing of metals, respectively “3-D-printing”, and bio-molecular laser related research and applications.
Host:
Gero von Plessen
Monday, January 15, 2018, 4:15pm, Hörsaal 28 D 001
Prof. Dr. Tilman Esslinger (ETH Zurich)
Building quantum systems from scratch: supersolids and more
Abstract:
Cooling and manipulating atomic gases have opened up new avenues to explore fundamental concepts in quantum many-body physics. Synthetically created potentials and control of atom-atom interactions have made it possible to tailor the properties of experimental systems at a microscopic level. This led to the concept of quantum simulation – here a system capable of reproducing the physics of many-body Hamiltonians. One of the goals of this approach is to provide answers to open questions in the context of condensed matter physics. An equally important frontier is the construction of novel systems, such as supersolids, which may at present not be realizable in solid-state or other systems. This path leads to new questions and surprises.
Host:
Christoph Stampfer
Monday, January 22, 2018, 4:15pm, Hörsaal 28 D 001
Dr. Martin Salinga (RWTH Aachen Unviersity)
How resistively switching materials open up new ways to process information
Abstract:
In the age of information vast amounts of data are available for processing. With the development of the ‘internet of things’, self-driving cars, etc. on the horizon, a further enormous expansion can be expected in the foreseeable future. Accordingly, the demand for devices that are capable of analysing such a plethora of data is increasing. Attracted by the efficiency of biological neural networks, current industrial and academic research endeavours to employ the principles of those natural examples in the design of specialized hardware applying various levels of abstraction. Resistively switching materials could form the basis of a new technology for neuromorphic information processing. The characteristic physical properties of a particularly promising subclass, i.e. phase change materials, will be analyzed and discussed with respect to their application potential in the area of neuromorphic electronics.
Host:
Matthias Wuttig
Monday, January 29, 2018, 4:15pm, Hörsaal 28 D 001
Prof. Dr. Eva Weig (Universität Konstanz)
Exploring classical coherence with nanomechanical systems
Abstract:
Nanomechanical resonators are freely suspended, vibrating bridges with nanoscale diameters. These nanostructures are receiving an increasing amount of attention, both in fundamental experiments addressing the foundations of quantum mechanics and for sensing applications, and show great promise as linking elements in hybrid nanosystems. In particular, doubly-clamped pre-stressed silicon nitride string resonators are explored as high Q nanomechanical systems enabling room temperature coherence times of several milliseconds. Here I will review how two strongly coupled flexural modes of the resonator constitute a classical two-mode system, which is employed as a model system to explore phenomena related to classical coherence. This yields fascinating insights into classical Landau-Zener dynamics, Rabi-, Ramsey- and Hahn-echo-type experiments, as well as Stückelberg interferometry – all well-known from their quantum counterparts.
The presented measurements allow deep insights into the decoherence of classical nanomechanical resonators. After a series of ground-breaking experiments on ground state cooling and non-classical signatures of nanomechanical systems in recent years, improving our understanding of decoherence might help pave the way for quantum nanomechanical systems.
Host:
Christoph Stampfer