Guest Lecture I: Time crystals, time quasicrystals, and time crystal dynamics
Time crystals are a novel phase of matter, characterised by persistent, repeating motion in the ground state. Therefore, a time crystal seems like a perpetual motion machine, and thus impossible. However, in quantum physics perpetual motion is OK if we cannot observe it. By sneaking through this crack, we can make time crystals. We explore time crystals made from magnetic quasiparticles within superfluid helium-3. The experiments are carried out at about one 10000 th of a degree above absolute zero. For example, we bring two time crystals to touch each other. The resulting two-level system is characterised by population oscillations and population transfer between the levels. Our experiments substantiate the theoretical speculations on the existence of time crystals, and provide a novel, magnetic building block for quantum devices – potentially even at room temperature.
Samuli Autti is a Lecturer and EPSRC Fellow at Lancaster University in the UK. He completed a Ph.D. in the Low Temperature Laboratory in Finland in 2017, working on superfluid helium-3. Samuli was the receiver of the 2020 Young Scientist Prize for a range of superfluid discoveries, awarded by the International Union of Pure and Applied Physics. His present work deals with the interfaces between classical and quantum physics, aiming to answer questions such as “what does it feel like to touch a quantum fluid” and “can we melt a time crystal, and whether the outcome is a time liquid”.
Guest Lecture III: Materials for sustainable energy
We have entered an era where energy management is a critical issue for humanity. The Intergovernmental Panel on Climate Change describes the existence of human-induced global warming as ‘unequivocal’. It is of critical importance that we switch as rapidly as possible to renewable, low- or zero-carbon energy sources. This lecture will outline the role materials must play in accelerating this progress towards truly sustainable energy. I will discuss both photovoltaics, i.e. solar cells, which convert light into electricity, and thermoelectrics, perhaps lesser-studied materials which convert heat into electricity. I will talk about the importance of nanoscale structure in these materials, and how it comes to dominate the way they ultimately work – something which can guide our rational design and lead us to the best possible results. I will also discuss how concepts of sustainability can guide research itself and offer some thoughts about the future of energy materials.
Mike is a Nottingham Research Fellow in the School of Physics and Astronomy at the University of Nottingham. He runs an independent program of research on thermoelectric materials. These can convert waste heat into useful electrical energy, or vice-versa provide cooling without moving parts and without greenhouse gases. Mike was lucky enough to return to Nottingham in 2020 after having done his first M.Sci. degree in Physics there before undertaking a Ph.D. in Sheffield and postdoctoral work in Australia and the UK.
Guest Lecture IV: Using Polymer to help refugees hydroponically grow food crops
Making Complex Fluids Work for Refugees. Our research on hydroponics is focussed on the production of high-value crops close to market (urban farming) with a low carbon and water footprint using polyurethane foam as a synthetic soil. I will show how a design of experiments approach can predict the productivity of crops from the reagents used in polyurethane synthesis through the properties of the foam. We connected our work on synthetic soils with a waste disposal problem posed by UNHCR - the UN's refugee agency. They saw dirty unused mattresses, we saw an alternative growth substrate and more than that ‘a problem’ that could actually help. In doing so we developed small-scale hydroponics with refugee communities for use at the household and community scale.
Tony leads the University of Sheffield’s programme in sustainability research, across pure and applied sciences, engineering and social sciences. His focus is on the global food, water and energy nexus challenge, harnessing the power of the sun for food production and renewable energy. His research covers sustainable synthesis, structure, processing, and applications of polymers using advanced analytical and measurement techniques. For example, renewable sources for polymer synthesis, organic photovoltaics, maximising the properties of polymers and biopolymers through flow-induced crystallisation, formulation of home and personal care products and polymer foams for high intensity urban agriculture. The emphasis throughout is on understanding the fundamental science & technology in order to minimise resource use. Tony holds a BSc and a PhD from the University of Manchester and a DSc from UMIST. In 1997 he moved to Sheffield and served as Head of Chemistry before becoming the Pro Vice Chancellor for the Faculty of Science from 2008 to 2016. Tony has also delivered the Royal Institution Christmas Lectures and has an OBE for services to science.