Fri, 26 Apr 2024

12:00 - 13:00
L3

On Spectral Data for (2,2) Berry Connections, Difference Equations, and Equivariant Quantum Cohomology

Daniel Zhang
(St John's College)
Abstract

We study supersymmetric Berry connections of 2d N = (2,2) gauged linear sigma models (GLSMs) quantized on a circle, which are periodic monopoles, with the aim to provide a fruitful physical arena for recent mathematical constructions related to the latter. These are difference modules encoding monopole solutions via a Hitchin-Kobayashi correspondence established by Mochizuki. We demonstrate how the difference modules arises naturally by studying the ground states as the cohomology of a one-parameter family of supercharges. In particular, we show how they are related to one kind of monopole spectral data, a deformation of the Cherkis–Kapustin spectral curve, and relate them to the physics of the GLSM. By considering states generated by D-branes and leveraging the difference modules, we derive novel difference equations for brane amplitudes. We then show that in the conformal limit, these degenerate into novel difference equations for hemisphere partition functions, which are exactly calculable. When the GLSM flows to a nonlinear sigma model with Kähler target X, we show that the difference modules are related to deformations of the equivariant quantum cohomology of X.

A joint image encryption based on a memristive Rulkov neuron with controllable multistability and compressive sensing
Li, Y Li, C Moroz, I Yang, Y Chaos Solitons & Fractals volume 182 114800- (May 2024)
Fri, 24 May 2024

12:00 - 13:00
Quillen Room

TBD

Duncan Laurie
(University of Oxford)
Abstract

TBD

Mon, 13 May 2024
14:15
L4

TBA

Simon Pepin Lehalleur
(KdV Institute, Amsterdam)
Smoothing in linear multicompartment biological processes subject to stochastic input
Browning, A Jenner, A Baker, R Maini, P Physical Review E: Statistical, Nonlinear, and Soft Matter Physics
Mon, 03 Jun 2024
15:30
L5

Geometric semi-norms in homology

Stephane Sabourau
(Université Paris-Est Créteil)
Abstract

The simplicial volume of a simplicial complex is a topological invariant
related to the growth of the fundamental group, which gives rise to a
semi-norm in homology. In this talk, we introduce the volume entropy
semi-norm, which is also related to the growth of the fundamental group
of simplicial complexes and shares functorial properties with the
simplicial volume. Answering a question of Gromov, we prove that the
volume entropy semi-norm is equivalent to the simplicial volume
semi-norm in every dimension. Joint work with I. Babenko.
 

Fri, 07 Jun 2024

12:00 - 13:00
Quillen Room

TBD

Samuel Lewis
(University of Glasgow)
Abstract

TBD

Mathematical Model-Driven Deep Learning Enables Personalized Adaptive Therapy.
Gallagher, K Strobl, M Park, D Spoendlin, F Gatenby, R Maini, P Anderson, A Cancer research (03 Apr 2024)
Thu, 23 May 2024

12:00 - 13:00
L3

Mathematical models for biological cooperation: lessons from bacteria

Maria Tatulea-Codrean
(University of Cambridge)

The join button will be published 30 minutes before the seminar starts (login required).

Further Information

Maria is a member of the Biological Fluid Mechanics group. Her current research interests revolve around the themes of flows (flows around and in between filaments, flows in membranes), motors (in particular, bacterial flagellar motors) and oscillators (synchronization of coupled non-linear oscillators, and biological rhythms more broadly).

Abstract
 
Cooperation occurs at all scales in the natural world, from the cooperative binding of ligands on
the molecular scale, to the coordinated migration of animals across continents. To understand
the key principles and mechanisms underlying cooperative behaviours, researchers tend to
focus on understanding a small selection of model organisms. In this talk, we will look through a
mathematician’s lens at one of the most well-studied model organisms in biology—the multiflagellated bacterium Escherichia coli.
 
First, we will introduce the basic features of swimming at the microscopic scale, both biological
(the flagellum) and mathematical (the Stokes equations). Then, we will describe two recent
theoretical developments on the cooperative dynamics of bacterial flagella: an
elastohydrodynamic mechanism that enables independent bacterial flagella to coordinate their
rotation, and a load-sharing mechanism through which multiple flagellar motors split the
burden of torque generation in a swimming bacterium. These results are built on a foundation of
classical asymptotic approaches (e.g., multiple-scale analysis) and prominent mathematical
models (e.g., Adler’s equation) that will be familiar to mathematicians working in many areas of

applied mathematics.

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