Until recently, astrophysicists observed our universe solely through light. Gravitational waves are a new tool. LISA is a future gravitational-wave observatory in space to observe gravitational waves from massive black holes orbited by small black holes or stars. When another body is nearby, resonances can occur in gravitational waves. This proposal studies these resonances because they contain information about the nearby objects and clues about the growth of black holes and galaxy formation. Additionally, correctly accounting for these resonances is necessary to perform precision tests of gravity and distinguish between resonances and deviations from general relativity.

A long-standing dream of theoretical physics is to explain the origins of spacetime and gravity from first principles and describe how our universe emerged from a primordial quantum “spacetime foam”. To realize this dream we will investigate correlation functions of curvature, which capture the behaviour of spacetime fluctuations and can connect the quantum micro-world to the macroscopic physics of the early universe. Using world-leading technical expertise and a new concept of quantum curvature, our key goal is to show that pure quantum spacetime can be the ultimate source of both gravitational interactions and structure formation in the universe.

The goal of the FASTER project is to develop new detector technologies and computing algorithms for particle physics experiments exploiting both high precision space and time information. Signs for new particle physics phenomena are extremely rare and hence require billions of collisions per second to be analysed in real-time. The High Luminosity phase of the Large Hadron Collider (HL-LHC) at CERN, starting in 2029, will increase the collision rates up to a factor 50 (depending on the experiment) allowing access to incredibly rare physics processes. The higher collision rates increase the overlap of the so-called physics events in space and time. Currently, the experiments rely solely on the detected spatial information to reconstruct individual events. Moreover, the required processing power increases exponentially with the number of collisions. The addition of time information to the three spatial dimensions measured, brings a solution to this challenge. The 4D event reconstruction demands both the development of new picosecond silicon pixel detectors and novel 4D-based pattern recognition algorithms. We will develop novel pixel sensors and electronics that provide precise temporal (20-30 ps) and spatial (5-10 μm) resolutions. Recent technological advances in silicon sensors show promising timing capabilities but need extensive R&D to achieve finer segmentation and improve radiation resistance. In addition, smart custom-made micro-electronics need to be developed to measure these fast-sensor signals with high precision. At the same time, more efficient and better scaling algorithms employing data reductions based on the timing information are required. Efficient 4D-reconstruction algorithms will be designed exploiting heterogeneous architectures to maximise performance at lower power consumption. Finally, quantum algorithms will be explored as a potential solution to reduce the exponential computing times of the pattern recognition algorithms for the track reconstruction. Spin-off applications of fast-timing tracking detectors within the field of mass spectrometry imaging will be pursuit with collaboration of the Maastricht Multi Modal Molecular Imaging (M4i) group in Maastricht. The FASTER consortium brings together detector physicists and computing experts from six Dutch universities and institutes across different experiments into a coherent R\&D effort to bring the 4D-tracking solution to life.

Understanding the quantum properties of spacetime is a key outstanding challenge of modern physics. I address it in a scenario called asymptotic safety, where our universe becomes self-similar at microscopic scales, like a fractal. To explore whether nature can realize this, I study, if particles like those we observe at macroscopic scales, are consistent with such a self-similarity. I will employ two independent methods to gain robust insights into this fascinating question. Additionally, I will lift an important approximation of previous studies, which neglected the difference between space and time for technical reasons.

Subatomic physics or particle physics investigates the elementary constituents of matter and radiation. The particles that are studied are the building blocks of atoms, like electrons, protons and neutrons, the particles that makes up light - the photon - and several more exotic ones. These particle can be studied by colliding them at very high energies and detecting the particles produced in the interaction (accelerator based physics) or by observing particles produced by extremely energetic processes in the universe (astroparticle physics). All the particles and their three interactions, electromagnetism, the weak nuclear force, responsible for radioactive decay and the strong force responsible for binding quarks in protons and neutrons and binding protons and neutrons in atomic nuclei can be described entirely by a quantum field theory called the Standard Model. The same Standard Model can be used to describe the early Universe just after the Big Bang, when the energy density was much higher. These conditions we can recreate at a small scale with particle accelerators like those at the international CERN laboratory near Geneva. Alternatively we can study high-energy particles produced in extreme processes in our Universe. Within the OSAF research school we are trying to answer some of the big questions on the origin of our Universe: What is the origin of mass? Where has the anti-matter of our Universe gone? What is the nature of Dark Matter, that seems to be five times more abundant than ordinary matter? What is the source of the ultra-high-energy cosmic rays? How can we unify Einstein.s theory of relativity with quantum physics? To answer these questions, the OSAF participates in a number of large scale experiments at international accelerator laboratories and observatories.