Markus Kunesch

Career

  • 2014-date*: PhD student, DAMTP, University of Cambridge
  • 2010-2014: Mathematical Tripos (MMath/BA), University of Cambridge

*Temporarily withdrawn to take up a position as Research Assistant at Queen Mary University of London until summer 2018. Expected date of reinstatement and thesis submission is July, 2018.

Research

Markus is a member of the Relativity and Gravitation research group in the Department of Applied Mathematics and Theoretical Physics. His current research is focused on solving Einstein’s equations numerically to tackle a wide range of problems in astrophysics, cosmology, mathematical general relativity, and AdS/CFT.

 

Markus is one of the core developers of the open-source numerical relativity code GRChombo (www.grchombo.orghttps://github.com/GRChombo).

Publications

  • Bantilan, H., Figueras, P., Kunesch, M., & Romatschke, P. (2017). Non-Spherically Symmetric Collapse in Asymptotically AdS Spacetimes. Physical Review Letters, 119(19), 191103
  • Figueras, P., Kunesch, M., Lehner, L., & Tunyasuvunakool, S. (2017). End Point of the Ultraspinning Instability and Violation of Cosmic Censorship. Physical Review Letters118(15), 151103.
  • Figueras, P., Kunesch, M., & Tunyasuvunakool, S. (2016). End point of black ring instabilities and the weak cosmic censorship conjecture. Physical Review Letters116(7), 071102 (Editors' Suggestion).
  • Cook, W. G., Figueras, P., Kunesch, M., Sperhake, U., & Tunyasuvunakool, S. (2016). Dimensional reduction in numerical relativity: Modified Cartoon formalism and regularization. International Journal of Modern Physics D25(09), 1641013.
  • Clough, K., Figueras, P., Finkel, H., Kunesch, M., Lim, E. A., & Tunyasuvunakool, S. (2015). GRChombo: Numerical relativity with adaptive mesh refinement. Classical and Quantum Gravity32(24), 245011.

Research highlights

Instabilities of black holes and cosmic censorship
We performed simulations that showed that the higher dimensional analogues of the black holes in our universe can break. Previously, this was only known for higher dimensional black holes with a rolled-up extra dimension (Lehner&Pretorius, PRL 105, 101102). General Relativity cannot describe the process of a black hole breaking, so in this setup the theory predicts its own demise. 

Simulation of a six dimensional black hole being torn apart by its own rotation.

In the process of hunting for black holes that break, we also uncovered a previously unknown instability of black rings in five dimensions: an elastic instability, which stretches the black ring without changing its thickness substantially.

GRChombo
In our simulations, we need to be able to resolve many different length scales efficiently. To this end, we have developed GRChombo, a new open-source numerical relativity code with fully adaptive mesh refinement. In the last few years, GRChombo has been used for many different problems ranging from cosmology to higher dimensional black holes. More information can be found at www.grchombo.org. The code is avaliable at https://github.com/GRChombo.