All the best evening meals feature after-dinner speakers, and those you'll be taking at Physics by the Lake are no exception.

### SEM-1: Metallic Hydrogen: The Holy Grail of High Pressure Physics

Graeme Ackland (University of Edinburgh)

At sufficiently high pressure, the electrons in the hydrogen molecules are squeezed out of their covalent bonds to become metallic. The basic properties of metallic hydrogen were already well described by the early theories of quantum mechanics in the 1930. Since then various predictions suggest it might be a room temperature superconductor, and superfluid, and supersolid or a supersonic rocket propellant. None of these has been detected experimentally, yet. In this after-dinner talk, I will cover the theoretical and experimental physics underlying the search. I will also give some insights into how research physics actually works, a discussion which may continue less formally in the bar later.

### SEM-2: The story of CASTEP

Mike Payne (Cambridge)

In this talk I shall talk about the rise of plane wave total energy pseudopotential calculations based on density functional and the role of CASTEP in establishing this methodology. I shall also describe the commercialisation of CASTEP and discuss some of the advantages and disadvantages of combining academic research with making money.

Mike is Professor of Computational Physics at the University of Cambridge, and a Fellow of the Royal Society. His research group focuses the development of new tools and technologies which are designed to be accessible to all researchers.

### SEM-3: Spin-orbit coupling effects on electrons, magnetic anisotropy and crystal field effect

Julie Staunton (Warwick)

Magnetic materials are typically characterised by a set of saturation magnetisation M, exchange A and anisotropy K constants combined into two important length quantities, an `exchange length' and a `domain wall thickness'. This talk will outline the relativistic generalisation of density functional theory and its electronic structure basis and show how it enables M, A and K to be calculated. The spin-orbit coupling influence on the electronic structure of materials will be described and its role in the origin of magnetic anisotropy, K, will be discussed in particular. The effects upon the exchange interactions within small clusters of magnetic atoms deposited on substrates or between magnetic impurities will also be described. In magnetic materials with 4f rare earth elements the strongly correlated f-electrons form non-spherically symmetric charge and magnetisation densities which interact with the surrounding charge distribution. In the talk it will be discussed how this crystal field effect and strong spin-orbit coupling lead to significant magnetic anisotropy in rare earth - transition metal magnets.

Julie is professor of physics at the University of Warwick. Her research involves electronic structure theory to describe phenomena in materials from 'first-principles' using high performance computing techniques. Projects in theoretical magnetism, metal and alloy physics and ab-initio studies of properties of strongly correlated electron materials.

### SEM-4: Symmetry fractionalization in quasi-one dimensional systems.

Raul Santos (Cambridge)

Symmetry plays a fundamental role in the classification of different phases on matter. In one and quasi-one dimensional systems, a complete understanding of different gapped phases is possible based on the presence of symmetry. It has been realized that among these symmetry protected states, new forms of quantum matter appear, with possible applications to quantum computing. I will review some classical examples and unveil the existence of new states in one and quasi-one dimensions.

Raul is a postdoctoral assistant at the university of Cambridge, having previously worked at the Weizmann institute in Israel, and Stony Brook university in the US. His research is in strongly correlated systems, using topics such as field theory and Bethe ansatz. Recently, he has worked a lot on topological phases of matter in strongly correlated systems.

### SEM-5: Schoedinger's elephants and quantum slide rules

Alexandre Zagoskin (Loughborough)

The fabrication and control of macroscopic artificial quantum structures, such as qubits, qubit arrays, quantum annealers and, recently, quantum metamaterials, have witnessed significant progress over the last 15 years. This was a surprisingly quick evolution from theoretical musings to what can now be called quantum engineering. The development of this discipline will play the decisive role in the Second Quantum Revolution. The main challenge before quantum engineering is to characterize and optimize large quantum coherent structures, which cannot be directly modelled by classical means. I will provide an overview of the situation and possible ways of moving forward.

Alex is head of the physics department at the Univeristy of Loughborough, and works in quantum engineering, quantum metamaterials, and quantum computing.

### SEM-6: Bound states of atoms and light

Mike Gunn (Birmingham)

Mike is professor of theoretical physics at the University of Birmingham. His research is in the field of many body quantum physics, where he tries to determine the patterns they form at low temperatures (where quantum mechanics dominates), which might be patterns in space (a simple example would be a crystal lattice) but usually have a pattern in a more exotic sense - in their velocities or correlations between pairs of the particles. Currently the rapid experimental developments in ultracold quantum gases are providing him (along with many other people!) several interesting theoretical problems.