|Prof. Lukas Novotny
I discuss our experiments with optically levitated nanoparticles in ultrahigh vacuum. Using both active and passive feedback techniques we cool the particle’s center-of-mass temperature to T = 100 μK and reach mean quantum occupation numbers of n ~ 15. I show that mechanical quality factors of Q = 109 can be reached and that damping is dominated by photon recoil heating. The vacuum-trapped nanoparticle forms an ideal model system for studying non-equilibrium processes, nonlinear interactions, and ultrasmall forces.
|Prof. Eleni Diamanti
Communication in a quantum world
Quantum technologies have the potential to revolutionize our society; they can offer unprecedented computational power for solving algorithms or simulating complex physical systems, enhance the precision of measurements, and improve the security and efficiency in communication networks. In this talk, we are interested in the latter application which widely uses quantum optics technology. We discuss the current landscape in quantum communication and cryptography, and focus in particular on recent photonic implementations, using encoding in discrete or continuous properties of light, of central quantum network protocols, enabling secret key distribution, verification of multiparty entanglement and transactions of quantum money, with security guarantees impossible to achieve with only classical resources. We also describe current challenges in this field and our efforts towards the miniaturization of the developed photonic systems, their integration into telecommunication network infrastructures, including with satellite links, as well as the practical demonstration of novel protocols featuring a quantum advantage for a wide range of tasks. These advances enrich the resources and applications of the emerging quantum networks that will play a central role in the context of future quantum-safe communications.
|Prof. Viola Vogel
Mechanobiology: a forceful player in health and disease
The opening of major new fields is typically driven by new technologies combined with a paradigm shift in thinking and approaching big problems. This also holds true for the rapidly growing field of mechanobiology through the recognition that proteins can act as mechano-chemical switches. How biology is taking advantage of mechano-chemical switching will be illustrated here in the context of bacterial adhesins. While commercial adhesins are typically rather non-specific when it comes to gluing objects together, and get weaker as the tensile load is increasing, bacteria have engineered a variety of highly specific adhesins with unique and unmatched mechanical properties. E. Coli, for example, evolved catch-bond adhesins that bind stronger to surfaces that are washed by fluid flow and can thereby colonize a range of technical and biological surfaces that are exposed to flow. S. Aureus specialized on entering host organisms through wound sites and have evolved adhesins that can distinguish health versus diseased tissue fibers. All atom simulations together with optical nanoprobes gave major novel insights into the intricate details how some of these bacterial adhesins work. Understanding how such adhesins are designed at the nanoscale and operate far outside of equilibrium to fulfill their tasks by enabling versus fighting infections is not only interesting academically, but can be exploited for a range of medical applications. Here we will discus how macrophages take advantage of E. coli’s adhesins to hunt and capture their prey, how penicillin-derived antibodies might interfere with this process, and how the adhesins of S. aureus can be exploited as mechanosensitive probes to read out the tensional states of tissue fibers.
|Prof. Jenny Nelson
Molecular electronic materials for solar energy conversion: understanding structure-function relationships
Molecular electronic materials such as conjugated polymers and small molecules have attracted intense interest for applications in solar energy conversion as well as to light emission, thin-film electronics and other fields. Their appeal lies in the potential to tune material properties (electronic, optical, mechanical and thermal) through control of chemical structure and molecular packing, whilst using facile fabrication methods. Achieving this goal has been challenging, however, due to the intrinsic disorder and structural heterogeneity of the materials and the lack of appropriate device-physics models to relate structure to physical properties. Recent developments in materials design, computational modelling and experimental characterisation have led to the demonstration of improved molecular materials systems for photovoltaic energy conversion. We will discuss the factors that control photovoltaic efficiency in molecular materials, considering the impact of chemical and physical structure on properties such as phase behaviour, electronic transport, light harvesting, and charge recombination and consider the limits to conversion efficiency in such systems. We will briefly address the application of conjugated polymers to the challenge of energy storage, as functional materials for both electrochemical devices and photocatalytic energy conversion.