Jaime Ruiz Zapatero United Kingdom United Kingdom

Research Software Engineer

I am a research software engineer at the Advanced Research Computing (ARC) centre of University College London (UCL) developing infrastructure for the LSST and Euclid cosmological surveys to enable new science. I also have a deep interest in accelerating Bayesian inference with gradient methods and Gaussian processes as tools for model-agnostic science.


  • Classical machine learning: developed tests of fundamental assumptions of modern Cosmology using Gaussian processes as tools for agnostic modelling.
  • High-dimensional statistical inference: developed gradient based inference algorithms to constrain thousands of parameters.
  • Big data reduction: co-author of the largest repository of consistently combined summary statistics in Cosmology from pixel maps.
  • Auto-differentiable programming: developed the first library of auto-differentiable methods for cosmology in Julia.


Click the pictures to head to each repository!


Gradient based sampler that uses one single energy level to explore large parameter spaces following Hamiltonian trajectories.


Fully differentiable Julia code to compute predictions of summary statistics of cosmological observables.


Biggest repository of summary statistics combined in a statistically consistent way in Cosmology using Python


Click to download the diplomas!

Work Experience

Research Software Engineer for LSST and Euclid at UCL, London (UK), Current
  • Euclid: building summary statistics from pixel maps.
  • LSST: speeding photometric uncertainty marginalisation.
Probabilistic programming engineer at the CBL Lab, Cambridge (UK), June-July 2023
  • Refactored the Turing.jl library for Bayesian inference from a monolithic into a microservice design by writing a new interface between Turing.jl's probabilistic programming language and external inference algorithms.
Natural language processing internship at Satalia (UK), Aug-Sept 2019
  • Developed a natural language processor to classify employees reports into the company's projects as well as a scheduler to asses and minimize project delays based on Monte Carlo simulations.

Teaching and other Responsibilities

  • Referee for OJA, EPJ-C, JCAP and APJ, free lance
  • Special Relativity and Symmetries tutor at St Peter's college, Oxford (2022)
  • BIPAC Cosmology journal club chair (2020-2022)
  • Leveling up physics mentor, Oxford (2021)