I am a probabilist. I am currently a Reader and Royal Society University Research Fellow at the University of Bath, in the probability group Prob-L@B. From 2018 to 2021, I was a Prize Fellow at the University of Bath. From 2016 to 2018, I was the G. H. Hardy Junior Research Fellow at New College and the Mathematical Institute at the University of Oxford. From 2013 to 2016, I was a PhD student in the Department of Statistics at the University of Oxford. My supervisor was Alison Etheridge.

I am interested in stochastic processes motivated by biology, reaction-diffusion equations, coalescent processes, branching processes and interacting particle systems.

In 2024, I was awarded the Erlang Prize by the INFORMS Applied Probability Society. I currently serve as an Associate Editor at Annals of Applied Probability.

Publications

Preprints

• Fluctuations for fully pushed stochastic fronts.
  Alison Etheridge, Raphaël Forien, Thomas Hughes and Sarah Penington.
  arXiv preprint arXiv:2604.00128.
  
• Existence, uniqueness and moment bounds for a spatial model of Muller's ratchet.
  João Luiz de Oliveira Madeira, Marcel Ortgiese and Sarah Penington.
  arXiv preprint arXiv:2603.06468.
  
• A functional law of large numbers for a spatial model of Muller's ratchet.
  João Luiz de Oliveira Madeira, Marcel Ortgiese and Sarah Penington.
  arXiv preprint arXiv:2603.06478.
  
• Can deleterious mutations surf deterministic population waves?
  João Luiz de Oliveira Madeira, Marcel Ortgiese and Sarah Penington.
  arXiv preprint arXiv:2607.12864.
  
• Convergence and front position for an FKPP-type free boundary problem.
  Julien Berestycki, Sarah Penington and Oliver Tough.
  arXiv preprint arXiv:2511.23457.
  

Journal Publications

Linked paper titles lead to arXiv versions; journal names link to the published versions.

• Integrated tick management strategies in fragmented peridomestic environments.
  Abby Barlow, Sarah Penington and Ben Adams.
  Journal of Theoretical Biology 633, 112534, 2026.
  
• Analysis of a household-scale model for the invasion of Wolbachia into a resident mosquito population.
  Abby Barlow, Sarah Penington and Ben Adams.
  Journal of Mathematical Biology 92, article 18, 2026.
  
• Epidemiological dynamics in populations structured by neighbourhoods and households.
  Abby Barlow, Sarah Penington and Ben Adams.
  Bulletin of Mathematical Biology 87, article 50, 2025.
  
• Branching random walk with non-local competition.
  Pascal Maillard and Sarah Penington.
  Journal of the London Mathematical Society, 109(6), e12919, 2024.
  
• A branching process with deletions and mergers that matches the threshold for hypercube percolation.
  Laura Eslava, Sarah Penington and Fiona Skerman.
  Annales de l’Institut Henri Poincaré, 60(2), pp 1418-1457, 2024.
  
• Brownian bees in the infinite swarm limit.
  Julien Berestycki, Éric Brunet, James Nolen and Sarah Penington.
  The Annals of Probability, 50(6), pp 2133-2177, 2022.
  
• Genealogies in bistable waves.
  Alison Etheridge and Sarah Penington.
  Electronic Journal of Probability, 27, 2022.
  
• Genealogy and spatial distribution of the N-particle branching random walk with polynomial tails.
  Sarah Penington, Matthew I. Roberts and Zsófia Talyigás.
  Electronic Journal of Probability, 27, 2022.
  
• A free boundary problem arising from branching Brownian motion with selection.
  Julien Berestycki, Éric Brunet, James Nolen and Sarah Penington.
  Transactions of the American Mathematical Society, 374(09), pp 6269-6329, 2021.
  
• Global existence for a free boundary problem of Fisher-KPP type.
  Julien Berestycki, Éric Brunet and Sarah Penington.
  Nonlinearity, 32(10), pp 3912–3939, 2019.
  
• Branching Brownian motion with decay of mass and the non-local Fisher-KPP equation.
  Louigi Addario-Berry, Julien Berestycki and Sarah Penington.
  Communications on Pure and Applied Mathematics, 72(12), pp 2487-2577, 2019.
  
• The spreading speed of solutions of the non-local Fisher-KPP equation.
  Sarah Penington.
  Journal of Functional Analysis, 275(12), pp 3259-3302, 2018.
  
• Branching Brownian motion, mean curvature flow and the motion of hybrid zones.
  Alison Etheridge, Nic Freeman and Sarah Penington.
  Electronic Journal of Probability, 22, 2017.
  
• A central limit theorem for the spatial Lambda Fleming-Viot process with selection.
  Raphaël Forien and Sarah Penington.
  Electronic Journal of Probability, 22, 2017.
  
• Branching Brownian motion and selection in the spatial Lambda Fleming-Viot process.
  Alison Etheridge, Nic Freeman, Sarah Penington and Daniel Straulino.
  The Annals of Applied Probability, 27(5), pp 2605-2645, 2017.
  
• The front location in BBM with decay of mass.
  Louigi Addario-Berry and Sarah Penington.
  The Annals of Probability, 45(6A), pp 3752-3794, 2017.
  

PhD students

• Zsófia Talyigás 2019 - 2022
  Joint with Matt Roberts.
  Currently a postdoc at BOKU University in Vienna, in Fernando Cordero's group. Formerly a postdoc at the University of Vienna with Emmanuel Schertzer.
  
• Carmen van-de-l'Isle 2021 - 2025
  Second supervisor. Joint with Marcel Ortgiese.
  
• Abby Barlow 2021 - 2025
  Second supervisor. Joint with Ben Adams.
  
• João Luiz de Oliveira Madeira 2022 - 2025
  Joint with Marcel Ortgiese.
  Currently a Florence Nightingale Bicentenary Fellow at the University of Oxford.
  

Postdocs

• Thomas Hughes 2023 - present