Symposium: “Condensed Matter Physics and Optics” Monday, December 20th, 2010 Program: 09.15 Welcome Thomas A. Henzinger (President IST Austria) 09.20 Seeing electrons in one and two dimensions: optics of carbon nanotubes and graphene Tony F. Heinz (Columbia University, Departments of Physics and Electrical Engineering) 10.00 Quantum optics and mesoscopic physics Atac Imamoglu (ETH Zurich, Quantum Photonics Group) 10.40 Graphene: CERN on the desk Mikhail I. Katsnelson (Radboud University of Nijmegen, Institute for Molecules and Materials) 11.20 Coffee break 11.40 A single molecule approach towards biological pattern formation Petra Schwille (Technical University Dresden, Biophysics) 12.20 Bone: A fascinating material Steve Weiner (Weizmann Institute of Science, Department of Structural Biology) 13.00 Lunch Location: Seminar Room Mondi 2 (Central Building) Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg Symposium: “Condensed Matter Physics and Optics” Abstracts: Time: 9.20 Seeing electrons in one and two dimensions: optics of carbon nanotubes and graphene Tony F. Heinz (Departments of Physics and Electrical Engineering, Columbia University) Two of the most fascinating nanoscale materials to have emerged over the past several years are based on the sp2-hybridized single layers of carbon: The one-dimensional system of carbon nanotubes and the two-dimensional system of graphene. In addition to the remarkable mechanical and electronic characteristics of these materials, their optical properties are of great interest and importance for fundamental science of low dimensional materials, for metrology, and for emerging photonic applications. We will discuss the nature of the excited states in these distinctive systems, how they are reflected in the optical properties of the materials, and how they can be measured experimentally. Time: 10.00 Quantum optics and mesoscopic physics Atac Imamoglu (ETH Zurich, Quantum Photonics Group) Spins confined in semiconductor quantum dots offer new possibilities for realizing quantum optical systems with unique properties. Conversely, optical measurement techniques provide a powerful tool for studying mesoscopic condensed-matter systems. Specific recent experiments I will discuss include the observation of photon blockade and the optical signatures of the Kondo effect. Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg Symposium: “Condensed Matter Physics and Optics” Time: 10.40 Graphene: CERN on the desk Mikhail Katsnelson (Radboud University of Nijmegen, Institute for Molecules and Materials) Graphene, a recently (2004) discovered two-dimensional allotrope of carbon (this discovery was awarded by Nobel Prize in physics 2010), has initiated a huge activity in physics, chemistry and materials science, mainly, for three reasons. First, a peculiar character of charge carriers in this material makes it a “CERN on the desk” allowing us to simulate subtle and hardly achievable effects of high energy physics. Second, it is the simplest possible membrane, an ideal testbed for statistical physics in two dimensions. Last not least, being the first truly two-dimensional material (just one atom thick) it promises brilliant perspectives for the next generation of electronics which uses mainly only surface of materials. I will tell about the first aspect of the graphene physics, some unexpected relations between materials science and quantum field theory and high-energy physics. Electrons and holes in this material have properties similar to ultrarelativistic particles (twodimensional analog of massless Dirac fermions). This leads to some unusual and even counterintuitive phenomena, such as finite conductivity in the limit of zero charge carrier concentration (quantum transport by evanescent waves) or transmission of electrons through high and broad poential barriers with a high probability (Klein tunneling). This allows to study subtle effects of relativistic quantum mechanics and quantum field theory in condensed-matter experiments, without accelerators and colliders. Some of these effects were considered as practically unreachable. Apart from the Klein tunneling, this is, for example, a vacuum reconstruction near supercritical charges predicted many years ago for collisions of ultra-heavy ions. Another interesting class of quantum-relativistic phenomena is related with corrugations of graphene, which are unavoidable for any twodimensional systems at finite temperature. As a result, one has not just massless Dirac fermions but massless Dirac fermions in curved space. Gauge fields, of the central concepts of modern physics, are quite real in graphene and one can manipulate them just applying mechanical stress. Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg Symposium: “Condensed Matter Physics and Optics” Time: 11.40 A single molecule approach towards biological pattern formation Petra Schwille (Technical University Dresden, Biophysics Group) Cell and developmental biology are immensely complex and rapidly growing fields that are particularly in need of quantitative methods to determine their key processes. To understand how cells polarize and develop into organisms, we need quantitative methods to determine concentration gradients and diffusion coefficients of key factors such as morphogens. Fluorescence Correlation Spectroscopy (FCS) is a powerful means for the study of concentrations, translocation processes, molecular association or enzymatic turnovers. It is fair to state that this technique raises strong hopes for quantitative systems biology. During the past years, we applied FCS to a variety of cell-associated phenomena. Recently, we established the possibility of determining how morphogen gradients form and maintain in living embryos, thus opening up a manifold of attractive applications in developmental biology. In another, more fundamental approach, we are presently aiming to identify minimal systems for biological self-organization that reveal fundamental mechanisms of how structures and patterns can emerge from the interplay of molecules. As a particularly exciting example for the power of minimal systems, self-organization of essential proteins of the bacterial cell division machinery could be shown in a simple assay, consisting of only two protein species, an energy source, and a membrane. Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg Symposium: “Condensed Matter Physics and Optics” Time: 12.20 Bone: A Fascinating Material Steve Weiner Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel 76100 Bone has fascinated scientists since the first studies in the 1690’s. Bone the material to this day still presents many enigmas. Bone is a composite material composed mainly of minute crystals of the mineral carbonated hydroxyapatite, the fibrous protein collagen and water. The crystals are plate-shaped, even though they crystallize in the hexagonal system. They form mainly inside the collagen fibril, where they do not grow from a saturated solution, but rather from a preformed highly disordered mineral phase called amorphous calcium phosphate. The crystals continue to grow and push the collagen molecules together. Older bone with more mineral fractures along crystal surfaces, whereas younger bone with less mineral fractures around collagen fibrils. Even though the building block of bone, the mineralized collagen fibril has a highly anisotropic structure, these fibrils are arranged into a complex structure that is much less anisotropic. This lamellar structure is thus better able to withstand mechanical challenges from all directions, making bone a sort of all-purpose “concrete” of the vertebrate skeleton. Finally certain bone cells are capable of removing older bone and others replace the space with newer bone. Bone thus also has self-healing capabilities. Despite the hundreds of years of investigation, much still remains to be understood about this fascinating material. Institute of Science and Technology Austria | Am Campus 1 | 3400 Klosterneuburg