Theoretical Physics - From Outer Space to Plasma

Dr. Rahil Valani, an expert in active matter, dives into the captivating world of nonlinear dynamics. He showcases how active particles, ranging from bacteria to robots, harness energy for movement. Valani particularly focuses on superwalking droplets, revealing their surprising hydrodynamic quantum analogs. The discussion also touches on the intricate behaviors of bouncing droplets on vibrating surfaces and their implications in the realm of non-equilibrium physics. Strap in for a journey through physics that’s as dynamic as the particles themselves!

Dumitru Călugăru, a research fellow at Oxford, dives into the fascinating world of flat band materials. He explains how engineering these materials can unlock exotic phases of quantum matter. The conversation covers the importance of band topology and how strong electron interactions can change the behavior of electrons in unique ways. He also touches on the historical context of Landau’s Fermi liquid theory and discusses experimental breakthroughs that illuminate the potential of flat bands in superconductivity.

In this conversation with Dr. Dominik Hahn, a quantum computing expert, listeners dive into the construction and programming of quantum computers. He demystifies the similarities between quantum and classical computing, showcasing how quantum programs run on superconducting devices. Hahn elaborates on the potential of quantum computers to tackle complex problems like simulating quantum systems and optimization. He also touches on the challenges of quantum error correction and the implications of current hardware limitations on algorithm performance.

Prof Sid Parameswaran discusses how quantum condensed matter physics has been revolutionized by “moiré materials”, made by stacking individual atomically thin layers such as graphene with a relative twist/offset between layers. The world of quantum condensed matter physics has recently been revolutionized by the advent of “moiré materials”, made by stacking individual atomically thin layers such as graphene (a two dimensional form of carbon) with a relative twist or offset between the layers. Electrons see a long-wavelength potential as they scatter from the positive ions in the different layers, leading to the formation of a new type of two-dimensional electron gas. In certain circumstances, the resulting electronic states are analogous to the Landau levels that lie at the heart of the quantum Hall effect, but form without an external magnetic field. This has led to the experimental realisation of the long-sought “fractional Chern insulator” state of matter, and has triggered an ongoing worldwide effort to explore other effects of the interplay of topology and interactions in this new setting. I’ll discuss the origins of the moiré phenomenon, and survey the exciting developments in the field, including some with links to Oxford.

While it was originally believed that only bosons and fermions were allowed by quantum mechanics, in fact, when objects are restricted to move on a two-dimensional plane, new types of particles called "anyons" can emerge. For much of the last century it was believed that the only types of particles allowed by quantum mechanics are bosons (such as photons, phonons, pions, Higgs, etc.) and fermions (such as electrons, muons, quarks, etc.). This rule of only two particle types turns out to be a reflection of the dimensionality of space. When objects are restricted to move on a two-dimensional plane, new types of particles, called "anyons" can emerge. While originally just a theoretical fantasy, such particles have recently been observed in several different types of experiments. I will discuss the history of this field, why it is viewed as important, and recent progress.

Prof Shivaji Sondhi explains how topology is applied to understanding properties of condensed matter systems, providing an introduction to topics including defects & solitons, the quantum Hall effect, and topological insulators. The mathematics of topology has been applied with increasing success to understanding the properties of condensed matter systems. Indeed, it is fair to say that over the past couple of decades, it has revolutionized our understanding of what forms of order are possible in quantum matter. In this talk, I will provide a brief, pedagogical introduction to some of the most well-known applications of topological ideas. These will include topics such as defects & solitons, the quantum Hall effect, and topological insulators.

Professor Prateek Agrawal discusses the ongoing crisis in cosmology regarding the measurement of the Hubble parameter by two separate probes in this Morning of Theoretical Physics talk from 9th November, 2024 Professor Prateek Agrawal discusses the Hubble tension. Cosmology has matured into a precision science over the last couple of decades. We are now in a position to test cosmological models to percent level precision, and cracks in our understanding of the universe have emerged. I will show how the measurement of the Hubble parameter by two separate probes has become an ongoing crisis in cosmology, and discuss some of the proposed solutions.

Professor Edward Hardy discusses how the network of cosmic strings that occurs in some theories of the early Universe evolves and emits gravitational waves in this Morning of Theoretical Physics talk from 9th November, 2024. Professor Edward Hardy discusses cosmic strings and gravitational waves from the early Universe. Cosmic strings are one-dimensional objects that often arise if a symmetry is spontaneously broken, as occurs in the early Universe in many theories of physics beyond the standard model. I will describe how the resulting network of strings evolves and in the process emits gravitational waves. These gravitational waves might be detectable in spectacularly precise searches today, and if discovered could give us information about physics at extremely high energies, far beyond any that could be explored directly e.g. in particle colliders.

Prof Alexander Mietke discusses recent findings in this field that have linked chirality in living systems to the formation of a left-right body axis in organisms and to a new kind of elasticity that is found in crystals formed by starfish embryos. Chirality describes objects and features that are distinct from their mirror image, a property that can be found in many biological systems ranging from spiral patterns of seashells over helical swimming paths of sperm cells to the shape of our hands and feet. This is rather surprising, given that most organisms develop from a single, round cell which shows no obvious signs of chirality. The physics of chirality in biological systems is a research area within the modern field of living matter that aims to identify the physical principals that underlie how chirality emerges during organism development and how the chiral nature of biological materials contributes to their highly unconventional mechanical properties

Dr Adrien Hallou presents a new methodology called 'spatial mechano-transcriptomics', which allows the simultaneous measurement of the mechanical and transcriptional states of cells in a multicellular tissue at single cell resolution. Over the last 10 years, advances in microscopy and genome sequencing have revolutionised our understanding of how molecular programmes contained in the genome control cellular behaviours such as cell division, differentiation or death, and how these behaviours are influenced by biochemical and mechanical signals from the cell environment. In this talk, I will present a new methodology called 'spatial mechano-transcriptomics', which allows the simultaneous measurement of the mechanical and transcriptional states of cells in a multicellular tissue at single cell resolution. This new framework provides a generic scheme for exploring the interplay of biomolecular and mechanical cues in tissues in a variety of contexts, such as embryonic development, tissue homeostasis and regeneration, but also in diseases such as cancer.