Name Activity "Analytical, Categorical and Algebraic Topology" "The research team investigates mathematical structures that are important in several basic areas of mathematics like geometry, representation theory, functional analysis, differential calculus or theory of approximation. The motivation also comes from outside mathematics, from computer science or physics where some of the mathematical structures that are studied are called upon as models. By application of methods from category theory the relation between these mathematical structures is studied. The compatibility of their fundamental constructions is investigated and a general study of their representability, as well as of their function space theory is undertaken. More specifically the theory of frames or locales uses order-theoretic notions to gain more insight in topological structures and to shed light on the use of choice principles in topology (or sometimes simply avoid them altogether). The theory of approach spaces provides the tools for obtaining quantified results in topology and in functional analysis, extending the isometric theory of Banach spaces. The team contributes to the development of the theory of semi-abelian categories and tensor categories Semi-abelian categories allow a unified setting for many important homological properties of non-abelian categories. Categories of quantum groups, of rings, of Lie-algebras and of crossed modules are typical non-abelian categories, often with a tensor structure. Abstract tensor categories lead to interesting non-commutative spaces (operator algebras) whose analytical properties are studied in connection with the properties of the associated category. The main emphasis is on representation categories of quantum deformations of semi-simple Lie groups." "Applied Physics" "Jan Danckaert" "We are a group of enthusiastic multidisciplinary young researchers from both the Departments of Applied Physics and Photonics (TONA) and Physics (DNTK). We use experimental and theoretical methods (nonlinear dynamics, stochastic processes, complex systems, electromagnetism, general relativity, etc.) to tackle and answer some fundamental challenges about nonlinear, complex and time-evolving systems. This combination allows an imaginative and insightful approach to problems, thereby avoiding the ""fundamental-applied"" polarisation. Besides photonic systems (such as e.g. semiconductor lasers) we also study other dynamical (e.g. biological) systems. The current areas of research are: - Dynamics of semiconductor lasers: nonlinear dynamics, bifurcation theory and stochastic processes are used in lasers, in particular semiconductor lasers. This theoretical study allows us to study the dynamic behaviour (e.g. bi- and multi-stability, excitability) of semiconductor lasers. These theoretical predictions are then tested experimentally in our labs. - Coherence properties of lasers: experimental and theoretical study of coherence properties of semiconductor lasers, and research into methods to modify and control the spatial coherence. In this way, we can generate spatially incoherent emission of a laser source. In our research we try to understand, model, optimize and apply this unique emission regime in innovative applications. - Metamaterials: metamaterials are complex structures that are composed of small, resonant electric circuits. These building blocks are much smaller than the wavelength of light, therefore they determine the electromagnetic properties of materials like atoms do in natural materials. Several problems are studied, ranging from the simulation of elementary metamaterial building blocks, over photonic devices based on metamaterials, to the development of metamaterial-based systems using the techniques of transformation optics. - Dissipative solitons: we study structures that arise in extended spatial systems in nature, both patterns as well as localized structures (spatial or dissipative solitons). We investigate the dynamic behaviour of these solitons (in time and space), studying the fundamental principles and unravelling the underlying bifurcation structure. - Coupled networks with delay: we study (small) networks of systems (oscillators) coupled with a time lag (delay). With such systems, synchronization may occur in which the oscillators vibrate with the same frequency and/or phase. In particular, we look at the existence and stability of such synchronized solutions and the influence of network topology and the delay. Such systems also have universal data processing properties (Reservoir Computing or Liquid State Machines) that we investigate and attempt to explain. - Non-linear oscillators with delay: We have recently shown that such systems show universal information processing properties (reservoir computing or Liquid State Machines). With only one non-linear node, we can get the same information-processing performance as with a neural network consisting of 400 nodes. We now further investigate the information processing capacity and attempt to explain and implement information processing concepts based on delay-coupled systems. - Dynamics of biological systems: we are focusing on the dynamics of toxin-antitoxin systems in bacteria and archaea. In cooperation with Structural Biology Brussels, we study models for gene regulation and function in the cell with different techniques: differential equations, stochastic methods, etc. We also study the dynamics of ecoystems, like the human gut flora (together with the Raes lab)." "Applied Physics and Photonics" "The Department of Applied Physics and Photonics at the VUB (TONA/TW/VUB) belongs to the Faculty of Engineering and Applied Sciences of our University. It consists of a group of about twenty researchers -engineers and physicists- who are working together on materials, components, devices and subsystems for bringing light into communication and information processing systems.These research themes go from fundamental research to near the market demonstrator systems. The group is also responsible for a successful Photonics curriculum for students in Electrical Engineering. The group is currently involved in thirty important research projects financed by the Flemish government , the Federal Science Foundation , the EC and Industry. The main research themes are : 1. Photonics in Digital Parallel Computing Demonstrators; 2. Micro-Optics for Optical Interconnects; 3. Polarisation in Photonic switching; 4. Organic Materials for Photonics; 5. Photonics in sensing and Nuclear Environments; 6. Holography and Diffractive Optics; 7. Optical Metrology; 8. Biomedical Optics; 9. Photonics and Optics in Education." Astronomy "TOPIC A : Extended Atmospheres (Van Rensbergen W.) - - Atmospheres of early type stars. Computer codes have been developed to calculate non LTE radiative transfer in extended atmospheres; the structure of these atmospheres; occupation numbers of atomic energy levels in these atmospheres; P-Cygni line spectra observed from early type stars with stellar wind; three dimentional line transfer for Be Star envelopes; active Stark effect in atmosheres of early type main sequence stars. Implemantation of these codes on MIDAS enbable comparison with observations. - - TOPIC B : Stellar Structure and Evolution (De Grève J.P.) - - Evolution of massive close binary systems. A computer code was developed allowing the simultaneous calculation of the structure and evolution of a binary system as a result of the evolution of the individual components as well as a result of changes of this evolution due to gravitational interaction between them. The applied research concentrates on early-type stars,Wolf Rayet stars and semidetached binaries. : Structure and Evolution of WR- binaries : Star Formation and Early Stellar Evolution - - TOPIC C : Observation of Stars: Photometry and Spectroscopy (Sterken C.) : Observations and analyses are carried out on the variability of b Cephei stars, LBV's, d Scuti stars, WR stars, Ap stars. : Long Term Photometry Variables Observing Programme." Astrophysics "The project started from 1996 to 1999 under the label OZR 252 'The Influence of Binaries on the number statistics and population synthesis of large groups of stars' and continued with a project OZR 188 from 1998 to 2001 'A library with evolutionary calculations of interacting binaries for a large variety of masses, mass ratio's and periods'. Both projects were joined together and are continued under the label FWOAL 157 (from 01.01.2000 tot 31.12.2003) The research unit Astrophysics develops research in the areas of: 1. Evolution of massive stars The evolution of a massive single star from main sequence-star, through WR-star ends with a Super Nova (SN), which leaves a white dwarf, neutron star (radio pulsar) or black hole as final product, i.e. a compact object (c). We study the influence of stellar wind on the evolution of these stars. The evolution of Massive Close Binaries (MCBs) is not only influenced by stellar wind but also by: mass loss through Roche Lobe Overflow, accretion and loss of mass in discs, the spiral of stars as a consequence of viscosity in the gravitational attraction field of a red giant. 2. Population Number Synthesis [PNS] In a starburst region the relative numbers of stars of different type is a function of age. These numbers have to be obtained following Single Star evolution schemes for the single stars (Maeder, Geneve) and the Binary Star evolution schemes for the binaries (Brussels). 3. Spectral Synthesis The spectra of galaxies are dominated by the radiation of the massive stars in that galaxy and the way that this radiation is transferred through the gas in the galaxy. Combining the results of the PNS, with the problem of radiative transfer in a galaxy, one can predict the intensity of a spectral feature as an indicator for the age of the galaxy. For instance, the equivalent width of the Balmer-betha emission line is a good index for the determination of the age of a galaxy. 4. Stellar dynamics. The density of stars in an starburst is enormous. The evolution of teh stars herein is influenced by the propability of collsions between them. The combination of single star evolution, binary evolution and dynamics describes the evolution of the starburst completely." "Biophysics and Biomedical Physics" "The group has three main research lines, with specific missions. Biomechanics and optical metrology: - Development of stroboscopic digital holography for vibration measurements of objects with time varying responses - Development of real-time moiré interferometry for shape measurement of dynamic objects, in combination with endoscopy for the study of shape and deformation of small objects such as the eardrum - Finite element modelling of middle ear and cochlear mechanics - Development of laser-vibrometry based techniques for diagnosis of arterosclerosis - Research on functional biomechanics in animals (in collaboration with the UA aboratory of Functional Morphology Molecular biophysics and spectroscopy: - Development of new multi-frequency electron paramagnetic resonance (EPR) methodologies for the study of paramagnetic biomolecules - Combined resonance Raman (RR) spectroscopy , multi-frequency EPR and density functional theory (DFT) study of heme-containing proteins to determine structure- function relations, including globins, chlorite dismutase and cytochromes. - EPR and DFT study of metal – biomolecule interactions, with a special focus on high-valent chromium - EPR and DFT analysis of materials for environmental-friendly chemistry, with a focus on transition-metal-containing catalysts - EPR and DFT analysis of organic solar cell materials for renewable energy - Towards biosensors and biocatalysis: research on how proteins behave in synthetic matrices Vestibular research: - Research of the human vestibular system with swirling chair and Vestibular Evoked Myogenic Potentials, 3D video oculography and the Subjective Visual-Vertical test. - Research on space sickness and human equilibrium" "Brussels Photonics Team" "Hugo Thienpont" "Photonics -the ""Science-and-Technology-to-Harness-Light""- is a discipline that involves fundamental research of photons, of light-matter interactions, and the development of novel technologies and applications based on the unique properties of light. Photonics leverages these unique properties to probe, sense, transmit, process, display and store information, and to accomplish a multitude of original functionalities, which cannot be achieved otherwise. Photonics Research at B-Phot , under the leadership of Prof. Hugo Thienpont, has been active in the field of micro-photonics for more than 20 years. For his excellent contribution to research, he received a Methusalem Grant for Micro-Photonics. During this time the research domain has changed dramatically. In the early days of micro-photonics a research group was already considered to be very successful when it was able to develop an individual type of micro-optical components. Today however it is indispensable to have access to an entire technology food chain comprising modelling, measurement, and rapid-prototyping of different types of 3D micro-optical components in a variety of materials, before one can even consider assembling the specialty components into practical proof-of-concept demonstrators." "Centre for Empirical Epistemology" "The research unit EMEP is mainly dealing with the interdisciplinary study of philosophical problems in the theory of knowledge, philosophical anthropology and the philosophy of mind and language. It is an explicit goal of the unit to bring empirical data to bear on philosophical problems, and to subject claims made in empirical science to philosophical analysis. Current topics of research are: 1. Major conceptual changes in science and philosophy; 2. Popularisation and between-discipline exchange of scientific knowledge; 3. Cognitive science-oriented study of the interaction between philosophy, science of vision and artistic practice; 4. Cognitive science oriented investigation of philosophical problems concerning visual perception, with a focus on the contrast between conscious and non-conscious vision and colour perception." "Centre for Molecular Separation Science & Technology" "Centre for Molecular Separation Science & Technology" "Centre Leo Apostel" "Diederik Aerts" "CLEA investigates the possibilities of interdisciplinary research, concentrating on the search for integrating world views. In a rapidly changing and complex society, scientific, social, and cultural knowledge is fragmented. This fragmentation leads to a growing gap between the exact sciences and the humanities (the two cultures), and between the layman and the specialist in general. Even more it entails the alienation of humankind from his surrounding nature/culture. The contemporary explosion of information further widens the gap between humankind and its fields of inquiry. CLEA's goal is to look for an integration of different approaches of reality, without the loss of specialised insight, but rather combining them into `world views' (views on the whole of reality). Therefore, CLEA analyses the conditions for such world views from an interdisciplinary point of view, enabling scientists from different disciplines to work together. They investigate possible conditions (methods and concepts) of integration of different fields of inquiry, enabling interdisciplinary exchange and communication between science and the humanities, between layman and specialist. The most recent insights and results in different disciplines are incorporated in this investigation. The investigations are concentrated in thematical projects: (1) the layered structure of reality, (2) the problem of change and synthesis, (3) the evolution of complexity, (4) the differences and similarities between science and art, (5) the evolution of historical world views, (6) the emergence of cognitive and social structures, (7) time and space in science and society, and (8) the development of interactive statistics."