Tim Zimmermann is a PhD Candidate at the Cosmology and Extragalactic Astrophysics, Institute of Theoretical Astrophysics, UiO. Tim is also part of the CompSci doctoral program. He will be defending his thesis for the degree of PhD, which was submitted for evaluation on 21.03.2025.
From the CompSci team we wish you good luck and all the best in your future endeavors!
→ Read more about the disputation in the website of the Institute of Theoretical Astrophysics
Programme
10:15 – Trial lecture: "Could pulsars be the progenitors of fast radio bursts?" – Aud 209, Svein Rosselands Hus
13:15 – Disputation: "On the wave-like nature of fuzzy dark matter; Modeling, phenomenology, and limits from the bottom up" – Aud 209, Svein Rosselands Hus
This event is open for everyone. No registration needed.
The PhD defence and trial lecture will be hybrid.
PhD candidate
Research group | Cosmology and Extragalactic Astrophysics
Main supervisor | Sijing Shen
Co-supervisor | Hans Winther
Affiliation | Institute of Theoretical Astrophysics, UiO
Contact | tim.zimmermann@astro.uio.no
Adjudication committee
Software Engineer, Philip Mocz, Center for Computational Astrophysics, Flatiron Institute
Associate Professor, Elisa M. Ferreira, Kavli Institute for the Physics and Mathematics of the Universe
Associate Professor, Tiago Pereira, University of Oslo
Chair of defense
Head of the department, Luc Rouppe van der Voort, University of Oslo
Short summary
On the wave-like nature of fuzzy dark matter; Modeling, phenomenology, and limits from the bottom up
Since the advent of observational evidence for the mysterious, gravitationally interacting substance dubbed dark matter (DM) about a century ago, physicists have worked relentlessly to uncover its microphysical nature. Impressive theoretical frameworks have been developed, and increasingly sophisticated detectors constructed—yet, no direct detection has been achieved. Astrophysics offers a complementary perspective: rather than asking what dark matter is, we ask how it behaves.
In this thesis, I focus on ultralight (or “fuzzy”) dark matter—a class of models that posits the DM particle to be roughly a hundred billion billion billion times lighter than a proton. So light, in fact, that its dynamics resemble those of a wave rather than a classical particle, giving rise to a distinct set of phenomena in a “fuzzy” universe.
To this end, I decompose FDM’s dynamics and phenomena into their elementary building blocks. Lower-dimensional considerations allow me to compare and further develop numerical solution strategies. By reconstructing all possible FDM wave states within the dwarf galaxy Leo II, I derive a robust mass constraint that updates four-decade-old folk wisdom. Finally, by assembling a population of simplified yet fuzzy cosmic filaments, one at a time, I statistically reproduce results of fully-fledged simulations at significantly lower cost.
Photo: Wave function density of ultralight DM for the dwarf spheroidal galaxy Leo II. The granular interference substructure is a hallmark feature of ultralight DM. Photo: Tim T. Zimmermann
