# Members

This is the first of three pages listing the members of the FotU program. On this first page we list the Official Members and Mentors of the program. The Official members are the are people who got a position at one (or at multiple) of the participating institutes to do research on a topic in the FotU research theme. The Mentors are three affiliate members, one PhD student of each institute, which guide the FotU PhD's through the program. Committee Members and Associate Members can be found on the other two pages.

# PhD Fellows

## MARTINE SCHUT

PhD Student

My research interests are in field theories, gravity and quantum systems. My main focus is on infrared quantum gravity, entanglement and decoherence. The goal of my research is to study large quantum systems that are entangled via gravity using mathematical techniques. I do this under the supervision of Anupam Mazumdar and Roland van der Veen at the Van Swinderen Institute and the Bernoulli Institute. At the moment I'm studying soft graviton emissions during potential scattering and I'm investigating the entropy of large entangled systems in different configurations, which are entangled via their mutual gravitational interaction.

## Kevin van Helden

PhD Student

My research is centered around interplay between mathematics and physics. To be more specific, my areas of interest include differential geometry, Lie theory and homological algebra on the mathematical side, and non-relativistic theories of gravity and field theory on the physical side. My current research projects are on classifying low dimensional strongly homotopy Lie algebras, which are a generalization of Lie algebras used in (string) field theories, and on understanding Chern-Simons theory for non-relativistic gravity and its relation with knots.

## Giovanni van Marion

PhD Student

One of the large open fundamental questions in physics is: "Why is there so much more matter than antimatter in the universe?" In regards to this question, I investigate the so-called sphaleron process, a hypothetical component of the solution. I apply an interdisciplinary approach to this problem by combining my theoretical physics background with mathematical techniques originally developed for chemistry. This project is made possible by working with both the Bernoulli and Van Swinderen Institutes here at the UG.

## Jann Aschersleben

PhD Student

My research is focused on the nature of dark matter, which is one of the biggest outstanding questions in physics. I develop machine learning algorithms to analyse the gamma-ray spectrum of dwarf galaxies with the upcoming Cherenkov Telescope Array (CTA) to search for a potential signal from dark matter self-annihilation. This project is supervised by Prof. Dr. R.F. Peletier and Dr. M. Vecchi from the Kapteyn Astronomical Institute, and Dr. M.H.F. Wilkinson from the Bernoulli Institute for Mathematics, Computer Science and Artificial Intelligence at the University of Groningen.

## Thomas Flöss

PhD Student

I study the use of 21 cm cosmology as a way to explore the physics of the early universe under the supervision of Prof. Dr. Diederik Roest and Dr. Daan Meerburg at the Van Swinderen Institute and Prof. Dr. Leon Koopmans at the Kapteyn Institute. The goal of my research is to determine predictions of cosmological inflation and determine to what extent the 21 cm signal from the Cosmological Dark Ages can be used to test them.

## Bohdan Bidenko

PhD Student

I study the tension between Hubble parameter estimates obtained with early and late Universe cosmological probes. I am looking for a possible solution to this problem by considering a wide range of standard cosmological model extensions and testing the effect of possible hidden systematic errors. In particular, the cosmological probes of my interest are the imprint of baryon acoustic oscillations in the large-scale structure and the cosmic microwave background, type Ia supernovae, and time-delay cosmography.

## Dijs de Neeling

PhD Student

In Newton’s theory of gravity, the two-body problem be solved easily, resulting in beautifully simple ellipses closing in on themselves (in principle) for all eternity. Einstein’s theory however becomes complicated so quickly that we cannot even exactly solve the ordinary Kepler problem! To get a grip on the properties of gravitational problems, we look at some theories slightly different from General Relativity, with more easily describable equations, guided, as often in Physics, by their symmetries.

## Robbert Scholtens

PhD Student

In my research, I try to understand the topology of the universe, and attempt to use spectral theory to that end. This is because, surprisingly, there is no consensus on the topology of the universe: it could be infinite and flat, as the ΛCDM model postulates, or the universe could be mutliconnected. That is to say, it could be like a donut, e.g, on the largest of scales, or something (far) more complicated. The main tool to find a -- hopefully conclusive! -- topological signature is the CMB anbd its statistical properties, as that is the probe of the universe at the largest of scales.

# Mentors

## Pranav Kukreti

Mentor & PhD Student

I’m a PhD student at the Kapteyn Astronomical Institute and ASTRON in the Netherlands. The goal of my PhD is to study the gas and life cycle of radio galaxies, especially galaxies that show multiple phases of activity. I’m trying to connect the evolutionary sequence of radio galaxies with information about the surrounding gas and investigate whether the gas and its properties influence the presence/life of the radio source (triggering activity) and, conversely, whether the gas is influenced by the presence of the radio source (e.g. producing fast outflows, feedback).

## Eric Pap

Mentor & PhD Student

In adiabatic quantum theory, one studies how an adjustment of a Hamiltonian changes its energies and eigenstates. For Hermitian Hamiltonians, one stays in the energy band, and the eigenstates acquire a special phase, known as the Berry or geometric phase, which only depends on the path in parameter space. However, if we allow for non-Hermitian Hamiltonians the picture changes; energy bands now connect via `spiral staircases'. The axis of such a staircase marks an `exceptional point'; using these you can permute one energy to another. My research aims to describe geometric phases and exceptional points simultaneously using parallel transport theory.

## Alba Kalaja

Mentor & PhD Student

I am a third-year PhD candidate at the Van Swinderen Institute (Cosmic Frontier). My research focuses mainly on primordial non-Gaussianity and Cosmic Microwave Background (CMB) physics. In particular, I am interested in studying the statistics of primordial fluctuations imprinted in the CMB. Recently, I have worked on determining the information content of cosmological higher-order correlation functions. I am also interested in characterizing the lensing convergence bispectrum of the CMB and incomputing the noise bias terms that arise in lensing reconstruction. This work is being developed within the Simons Observatory collaboration.