Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.
OCIAM TBC
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Dr Edwina Yeo is an applied mathematician working at the interface of continuum mechanics and mathematical biology. She specialises in developing mathematical models for biological and biomedical fluid-mechanics processes, with research spanning regenerative medicine, nanotechnology, microbiology and geology. Her recent work includes models of bacterial adhesion in fluid flow, Von Willebrand Factor dynamics in arterial flows, and microscale contaminant behaviour extracted from imaging data.
Her publications appear in journals such as Biomechanics and Modelling in Mechanobiology, Advanced Materials, and Royal Society Interface, alongside recent collaborative preprints. She is currently an EPSRC National Fellow in Fluid Dynamics at UCL and a visiting research fellow in OCIAM.
The Dean–Kawasaki Equation: Theory, Numerics, and Applications
Abstract
The Dean–Kawasaki equation provides a stochastic partial differential equation description of interacting particle systems at the level of empirical densities and has attracted considerable interest in statistical physics, stochastic analysis, and applied modeling. In this work, we study analytical and numerical aspects of the Dean–Kawasaki equation, with a particular focus on well-posedness, structure preservation, and possible discretization strategies. In addition, we extend the framework to the Dean–Kawasaki equation posed on smooth hypersurfaces. We discuss applications of the Dean–Kawasaki framework to particle-based models arising in biological systems and modeling social dynamics.
Sharp habitat shifts, evolutionary tipping points and rescue: Quantifying the perilous path of a specialist species towards a refugium in a changing environment via a PDE model
Abstract
Specialist species thrive under specific environmental conditions in narrow geographic ranges and are widely recognized as heavily threatened by climate deregulation. Many might rely on both their potential to adapt and to disperse towards a refugium to avoid extinction. It is thus crucial to understand the influence of environmental conditions on the unfolding process of adaptation. I will present a PDE model of the eco-evolutionary dynamics of a specialist species in a two-patch environment with moving optima. The transmission of the adaptive trait across generations is modelled by a non-linear, non-local operator of sexual reproduction. In an asymptotic regime of small variance, I justify that the local trait distributions are well approximatted by Gaussian distributions with fixed variances, which allows to report the analysis on the closed system of moments. Thanks to a separation of time scales between ecology and evolution, I next derive a limit system of moments and analyse its stationary states. In particular, I identify the critical environmental speed for persistence, which reflects how both the existence of a refugium and the cost of dispersal impact extinction patterns. Additionally, the analysis provides key insights regarding the path towards this refugium. I show that there exists a critical environmental speed above which the species crosses a tipping point, resulting into an abrupt habitat switch from its native patch to the refugium. When selection for local adaptation is strong, this habitat switch passes through an evolutionary ‘‘death valley’’ that can promote extinction for lower environmental speeds than the critical one.
OCIAM Post-doc Talks
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Dr Finyashu Kaka is a materials scientist specialising in sustainable energy technologies, advanced functional materials, and computational modelling. His work spans organic photovoltaics, solid-state and metal-ion batteries, MXene-based materials, and next-generation thermal barrier coatings. He combines physics-based modelling with machine-learning methods to understand and optimise process–structure–property relationships in energy devices. His research appears in leading journals, and he holds several patents in flexible electronics and energy-efficient thermal systems. He is currently working with Professor Jon Chapman as a postdoctoral researcher in OCIAM.
Subspace Correction Methods for Convex Optimization: Algorithms, Theory, and Applications
Abstract
Speaker Yongho Park will talk about 'Subspace Correction Methods for Convex Optimization: Algorithms, Theory, and Applications'
This talk considers a framework of subspace correction methods for convex optimization, which provides a unified perspective for the design and analysis of a wide range of iterative methods, including advanced domain decomposition and multigrid methods. We first develop a convergence theory for parallel subspace correction methods based on the observation that these methods can be interpreted as nonlinearly preconditioned gradient descent methods. This viewpoint leads to a simpler and sharper analysis compared with existing approaches. We further show how the theory can be extended to semicoercive and nearly semicoercive problems. In addition, we explore connections between subspace correction methods and other classes of iterative algorithms, such as alternating projection methods, through the lens of convex duality, thereby enabling a unified treatment. Several applications are presented, including nonlinear partial differential equations, variational inequalities, and mathematical imaging problems. The talk concludes with a discussion of relevant and emerging research directions.
The rogue within: uncovering hidden heterogeneity in heart cell networks
Abstract
Normal heart function relies of the fine-tuned synchronization of cellular components. In healthy hearts, calcium oscillations and physical contractions are coupled across a synchronised network of 3 billion heart cells. When the process of functional isolation of rogue cells isn’t successful, the network becomes maladapted, resulting in cardiovascular diseases, including heart failure and arrythmia. To advance knowledge on this normal-to-disease transition we must first address the lack of a mechanistic understanding of the plastic readaptation of these networks. In this talk I will explore coupling and loss of synchronisation using a mathematical model of calcium oscillations informed by experimental data. I will show some preliminary results pointing at the heterogeneity hidden behind seemingly uniform cell populations, as a causative mechanism behind disrupted dynamics in maladapted networks.
14:15
A toric case of the Thomas-Yau conjecture
Abstract
We consider a class of Lagrangian sections L contained in certain Calabi-Yau Lagrangian fibrations (mirrors of toric weak Fano manifolds). We prove that a form of the Thomas-Yau conjecture holds in this case: L is isomorphic to a special Lagrangian section in this class if and only if a stability condition holds, in the sense of a slope inequality on objects in a set of exact triangles in the Fukaya-Seidel category. This agrees with general proposals by Li. On
surfaces and threefolds, under more restrictive assumptions, this result can be used to show a precise relation with Bridgeland stability, as predicted by Joyce. Based on arXiv:2505.07228 and arXiv:2508.17709.
15:00
Geometrically confined quantum systems
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Dr Rob Van Gorder’s research focuses on how physical phenomena can be described, predicted, and controlled using applied mathematics. He works across mathematical modelling, analytical and asymptotic methods, and numerical simulation, applying this combination to a wide range of physical systems.
His interests in fluid dynamics centre on fundamental flow structures—such as vortices, bubbles, waves, and boundary layers—and how they evolve, persist, or break apart. He also studies spatial instabilities and pattern formation, investigating how mechanisms such as Turing and Benjamin–Feir instabilities extend to heterogeneous or non-autonomous systems arising in chemistry, physics, biology, and epidemiology.
In theoretical physics, Dr Van Gorder works on quantum mechanics, quantum fluids, and nonlinear waves, including the dynamics of Bose–Einstein condensates, quantised vortices in superfluid helium, and confined quantum systems. Across these areas, he aims to understand how nonlinear and quantum systems behave under realistic constraints and external forcing.
His recent publications include work on pattern formation and diffusive instabilities in Proceedings of the Royal Society A.
Abstract
You will likely be familiar with the notion of a hydrogen atom, having seen something about its discrete energy levels and orbitals at some point or another. This is an example of a quantum system. In this talk, we explore what transpires when taking a quantum system and placing it into a three-dimensional container having some prescribed geometry. In the limit where the container is large (relative to the natural lengthscale of the quantum system), its influence over the quantum system is negligible; yet, as the container is made small (comparable to the aforementioned lengthscale), geometric information intrinsic to the container plays an important role in determining the energy and orbital structure of the system. We describe how to do (numerically-assisted) perturbation theory in this small-container limit and then match it to the large-box regime, using a combination of these asymptotics and direct simulations to tell the story of geometrically confined quantum systems. Much of our focus will be on linear Schrödinger equations governing single-particle quantum systems; however, time permitting, we will briefly discuss how to do similar things to study geometrically confined nonlinear Schrödinger equations, with geometric confinement of Bose-Einstein condensates being a primary motivation. Geometric confinement of an attractive Bose-Einstein condensate can, for instance, modify the collapse threshold and enhance stability, with the particular choice of confining geometry shifting the boundary of instability, staving off the collapse which is prevalent in three-dimensional attractive condensates.
The life of a Turing Pattern
Abstract
We survey the life of a Turing pattern, from initial diffusive instability through the emergence of dominant spatial modes and to an eventual spatially heterogeneous pattern. While many mathematically ideal Turing patterns are regular, repeating in structure and remaining of a fixed length scale throughout space, in the real world there is often a degree of irregularity to patterns. Viewing the life of a Turing pattern through the lens of spatial modes generated by the geometry of the bounded space domain housing the Turing system, we discuss how irregularity in a Turing pattern may arise over time due to specific features of this space domain or specific spatial dependencies of the reaction-diffusion system generating the pattern.
14:15
Metric wall-crossing
Abstract
16:00
OCIAM TBC
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Dr Stuart J. Thomson is an applied mathematician whose research sits at the intersection of mathematics, physics, and engineering. He works closely with table-top experiments to uncover how complex fluid and soft-matter systems give rise to novel emergent phenomena through nonlinear dynamics, many-body interactions, and geometric confinement. His interests include interfacial hydrodynamics, self-assembly, active and driven matter, interfacial robotics, transport phenomena, and fluid–structure interaction.
He is currently leading the project “The statistical physics of hydrodynamic random walkers: experiments and theory”, which combines experimental and theoretical approaches to understand how fluid-mediated interactions shape the behaviour of randomly moving microscopic walkers. Dr Thomson is based in the School of Engineering, Mathematics and Technology at the University of Bristol.
Resonances as a computational tool
Abstract
Speaker Katharina Schratz will talk about 'Resonances as a computational tool'
A large toolbox of numerical schemes for dispersive equations has been established, based on different discretization techniques such as discretizing the variation-of-constants formula (e.g., exponential integrators) or splitting the full equation into a series of simpler subproblems (e.g., splitting methods). In many situations these classical schemes allow a precise and efficient approximation. This, however, drastically changes whenever non-smooth phenomena enter the scene such as for problems at low regularity and high oscillations. Classical schemes fail to capture the oscillatory nature of the solution, and this may lead to severe instabilities and loss of convergence. In this talk I present a new class of resonance based schemes. The key idea in the construction of the new schemes is to tackle and deeply embed the underlying nonlinear structure of resonances into the numerical discretization. As in the continuous case, these terms are central to structure preservation and offer the new schemes strong geometric properties at low regularity.
Identifiability of stochastic and spatial models in mathematical biology
Abstract
14:15
Towards a Bogomolov-Miyaoka-Yau inequality for symplectic 4-manifolds
Abstract
The Bogomolov-Miyaoka-Yau inequality for minimal compact complex surfaces of general type was proved in 1977 independently by Miyaoka, using methods of algebraic geometry, and by Yau, as an outgrowth of his proof of the Calabi conjectures. In this talk, we outline our program to prove the conjecture that symplectic 4-manifolds with $b^+>1$ obey the Bogomolov-Miyaoka-Yau inequality. Our method uses Morse theory on the gauge theoretic moduli space of non-Abelian monopoles, where the Morse function is a Hamiltonian for a natural circle action and natural two-form. We shall describe generalizations of Donaldson’s symplectic subspace criterion (1996) from finite to infinite dimensions. These generalized symplectic subspace criteria can be used to show that the natural two-form is non-degenerate and thus an almost symplectic form on the moduli space of non-Abelian monopoles. This talk is based on joint work with Tom Leness and the monographs https://arxiv.org/abs/2010.15789 (to appear in AMS Mathematical Surveys and Monographs), https://arxiv.org/abs/2206.14710 and https://arxiv.org/abs/2410.13809.
Topology of smooth Gaussian fields
Abstract
Gaussian fields arise in a variety of contexts in both pure and applied mathematics. While their geometric properties are well understood, their topological features pose deeper mathematical challenges. In this talk, I will begin by highlighting some motivating examples from different domains. I will then outline the classical theory that describes the geometric behaviour of Gaussian fields, before turning to more recent developments aimed at understanding their topology using the Wiener chaos expansion.
TBA
Abstract
TBA
16:00
OCIAM TBC
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Tobias Grafke's research focuses on developing numerical methods and mathematical tools to analyse stochastic systems. His work spans applications in fluid dynamics and turbulence, atmosphere–ocean dynamics, and biological and chemical systems. He studies the pathways and occurrence rates of rare and extreme events in complex realistic systems, develops numerical techniques for their simulation, and quantifies how random perturbations influence long-term system behaviour.