Name: 6th EPS Conference on Gravitation
Start: 2026-06-01T08:00:00+02:00
End: 2026-06-03T14:00:00+02:00
Location: University of Stavanger

6th EPS Conference on Gravitation

from Monday, 1 June 2026 (08:00) to Wednesday, 3 June 2026 (14:00)

Monday, 1 June 2026

08:15 Registration
Registration
08:15 - 08:50
Room: Ullandhaug Campus, AR Ø-110

08:50 Welcome
Welcome
08:50 - 09:00
Room: Ullandhaug Campus, AR Ø-110
09:00 Dark energy: A cosmological constant, quintessence or something else? - Ed Copeland (U Nottingham)
Dark energy: A cosmological constant, quintessence or something else?
- Ed Copeland (U Nottingham)
09:00 - 09:35
Room: Ullandhaug Campus, AR Ø-110 Dark Energy is the term given to the dominant energy density in the universe today which appears to be causing it to accelerate. A key question then is what is responsible for the dark energy? There are three favoured candidates: a cosmological constant which has a fixed constant energy density, a quintessence field which has an energy density which varies with time or a modification of Einstein's General Theory of Relativity, where the presence of extra curvature terms could lead to the observed acceleration. We will discuss these options, and their problems (they all have some!), and comment on the recent tentative evidence emerging from the DESI collaboration of dynamical dark energy - exciting but not as you would expect from quintessence!
09:35 Early-universe cosmology with LISA - Marek Lewicki (U Warsaw)
Early-universe cosmology with LISA
- Marek Lewicki (U Warsaw)
09:35 - 10:10
Room: Ullandhaug Campus, AR Ø-110 The Laser Interferometer Space Antenna (LISA) offers a unique opportunity to probe the early universe through the detection of stochastic gravitational wave backgrounds. In this talk, I will review recent progress within the LISA Cosmology Working Group in analyzing these signals as probes of physics beyond the Standard Model. I will focus on early-universe sources such as first-order cosmological phase transitions and cosmic strings, highlighting their predicted signatures and the key challenges that must be addressed to fully exploit LISA’s scientific potential.
10:10 Coffee Break
Coffee Break
10:10 - 10:40
Room: Ullandhaug Campus, AR Ø-110
10:40 Cosmological tests of gravity beyond general relativity - David Mota (U Oslo)
Cosmological tests of gravity beyond general relativity
- David Mota (U Oslo)
10:40 - 11:15
Room: Ullandhaug Campus, AR Ø-110 Several modifications to General Relativity have been proposed to explain the nature of dark energy and the observed accelerated expansion of the Universe. However, such theories are stringently constrained by local tests of gravity and by observations of gravitational waves. In this talk, I begin by outlining the conditions under which theories beyond General Relativity can remain viable in light of these constraints, and by describing how they are expected to manifest across different astrophysical systems and in their cosmological signatures. Building on this framework, I will present a range of observational tests that exploit current and next‑generation astronomical surveys to probe gravity on multiple scales. In particular, I will show how the nonlinear dynamics and observable properties of galaxies and galaxy clusters provide especially promising avenues for constraining theoretical models of modified gravity.
11:15 Testing general relativity with cosmological observations - Ruth Durrer (U Geneva)
Testing general relativity with cosmological observations
- Ruth Durrer (U Geneva)
11:15 - 11:50
Room: Ullandhaug Campus, AR Ø-110 General Relativity (GR) is immensely successful. With the late discovery of gravitational waves from black hole and neutron star mergers, it has passed all the tests with flying colors. But so far, all observations have mainly tested the vacuum equations of GR. The most important non-vacuum case, cosmology, is in agreement with GR only after the introduction of two otherwise unknown components, 'Dark Matter' and 'Dark Energy' which amount to about 95% of the total energy budget of the present Universe. This led people in the field to question the validity of GR for cosmology. Might it be that GR is flawed on large, cosmological scales? Or in the presence of matter in general? But how can we test Einstein's equation in the presence of matter? Can't we simply move any modification of the Einstein tensor to the right hand side and call it a 'dark matter/energy' component? In my talk I shall discuss possible ways (partially) out of this dilemma. How to test both, the left and the right hand side of Einstein's equations with cosmological observations.
11:50 The relativistic galaxy bispectrum - Chris Clarkson (Queen Mary U of London)
The relativistic galaxy bispectrum
- Chris Clarkson (Queen Mary U of London)
11:50 - 12:25
Room: Ullandhaug Campus, AR Ø-110 The galaxy bispectrum will play an important role for future galaxy surveys. On large scales it will be a key probe for measuring primordial non-Gaussianity, and hence help discriminate between different inflationary models and other theories of the early universe. On these scales, a variety of relativistic effects come into play once the galaxy number-count fluctuation is projected onto the past light cone. The Fourier-space galaxy bispectrum is complex, with the imaginary part arising from leading-order relativistic corrections. Detection of the imaginary part is potentially a smoking gun signal of relativistic contributions. We will discuss whether next-generation surveys could make such a detection. Further, we will discuss how relativistic effects break parity invariance of the observed trispectrum.
12:25 Lunch Break
Lunch Break
12:25 - 13:55
Room: Ullandhaug Campus, AR Ø-110
13:55 A status on cosmic backreaction and its relation to model-independent cosmology - Sofie Marie Koksbang (U Southern Denmark)
A status on cosmic backreaction and its relation to model-independent cosmology
- Sofie Marie Koksbang (U Southern Denmark)
13:55 - 14:30
Room: Ullandhaug Campus, AR Ø-110 The structures of the Universe can affect the large-scale cosmic dynamics. This effect is known as cosmic backreaction. Although the effect has been known and studied for decades, it is still unclear how important the effect is in our Universe. One can attempt to quantify the effect in several different ways, but the resulting estimates vary wildly, depending on the introduced approximations. It is therefore unclear to what extent (if at all) backreaction is related to dark energy, cosmological tensions and how important it is in relation to testing theories of gravity beyond general relativity. In this talk, I will present the concept of cosmic backreaction and how it may be related to dark energy and cosmic tensions, as well as why it may be particularly important when studying gravity beyond general relativity. I will also review why backreaction is so difficult to quantify and discuss the necessary steps remaining before we can make truly trustworthy theoretical predictions of its importance in our universe. Lastly, I will discuss the possibility of quantifying backreaction through observations and how this fits into a larger strategy of studying observations model-independently.
14:30 Contributed Talks: Monday I
Monday I
14:30 - 15:30
Room: Ullandhaug Campus, AR Ø-110
Contributions

14:30 TBA - Germano Nardini (U Stavanger)

14:50 Extended quintessence - Abdolali Banihashemi (U Oslo)

15:10 Stochastic scalar-tensor theories - Yoann Launay (U Cambridge)
15:30 Coffee Break
Coffee Break
15:30 - 16:00
Room: Ullandhaug Campus, AR Ø-110
16:00 Contributed Talks: Monday II
Monday II
16:00 - 17:00
Room: Ullandhaug Campus, AR Ø-110
Contributions

16:00 Tests of general relativity with the gravitational wave transient catalog 4.0 - Ofek Birnholtz (Bar-Ilan U)

16:20 Measuring cosmic expansion with gravitational waves: hints from binary black hole-galaxy cross-correlations - Sayantani Bera (Aix-Marseille U)

16:40 High precision predictions for next generation gravitational wave observatories: the post-Newtonian frontier at the seventh order - Matteo Pegorin (U & INFN Padova)
17:00 Session on Future Challenges: Bridging Planckian physics to cosmological observables (convener: Mercedes Martin-Benito)
Bridging Planckian physics to cosmological observables (convener: Mercedes Martin-Benito)
17:00 - 18:00
Room: Ullandhaug Campus, AR Ø-110

18:00 Reception / Poster session

18:00 - 19:30
Room: Ullandhaug Campus, AR Ø-110
Tuesday, 2 June 2026
09:00 General aspects of quantum cosmology - Martin Bojowald (Penn State U)
General aspects of quantum cosmology
- Martin Bojowald (Penn State U)
09:00 - 09:35
Room: Ullandhaug Campus, AR Ø-110 Quantum cosmology is often analyzed in a model-dependent way, following specific quantization schemes. This talk instead focuses on general properties and related questions implied by the common separation of modes into an expanding background and evolving perturbations. While this separation is well-understood classically, it gives rise to important questions about Casimir energies, covariance, and modified dynamics on the quantum level.
09:35 Singularities and their crossing in gravity and cosmology - Alexander Kamenshchik (U & INFN Bologna)
Singularities and their crossing in gravity and cosmology
- Alexander Kamenshchik (U & INFN Bologna)
09:35 - 10:10
Room: Ullandhaug Campus, AR Ø-110 We discuss the nature of singularities and possibility of their crossing in gravity and cosmology. We study at which conditions singularities can disappear in quantum cosmology and how quantum particles behave in the vicinity of singularities. Some attempts to develop general approach to the connection between the field reparametrization and the elimination of singularities is presented as well.
10:10 Coffee Break
Coffee Break
10:10 - 10:40
Room: Ullandhaug Campus, AR Ø-110
10:40 The initial boundary value problem for the Einstein vacuum equations with umbilic boundary - Grigorios Fournodavlos (U Crete)
The initial boundary value problem for the Einstein vacuum equations with umbilic boundary
- Grigorios Fournodavlos (U Crete)
10:40 - 11:15
Room: Ullandhaug Campus, AR Ø-110 In this talk, we will discuss the initial boundary value problem in general relativity from a mathematical point of view. We will first make the analogy to the classical Cauchy problem for the Einstein equations, first resolved by Yvonne Choquet-Bruhat in 1952, and highlight some desired properties that a potential treatment of timelike boundaries should have. Then, we will go over the various technical difficulties that arise in such an endeavor. The main result that we will present in the end concerns the local well-posedness of the problem for homogeneous Neumann conditions, in geometric terms, when the boundary is umbilic. This is joint work with Jacques Smulevici.
11:15 Structures and dynamics in slowly expanding cosmological spacetimes - Zoe Wyatt (U Cambridge)
Structures and dynamics in slowly expanding cosmological spacetimes
- Zoe Wyatt (U Cambridge)
11:15 - 11:50
Room: Ullandhaug Campus, AR Ø-110 I will survey some recent joint work studying the dynamics of relativistic and non-relativistic fluids on cosmological FLRW spacetimes. Interesting nonlinear features arise from the dynamics, that can lead to finite-time shock formation in a mechanism unlike the classical Jeans instability.
11:50 Gravitational waves from early universe phase transitions - Mark Hindmarsh (U Helsinki & U Sussex)
Gravitational waves from early universe phase transitions
- Mark Hindmarsh (U Helsinki & U Sussex)
11:50 - 12:25
Room: Ullandhaug Campus, AR Ø-110 In extensions of the Standard Model of particle physics, phase changes associated with symmetry-breaking or confinement could have been first order transitions, featuring the nucleation, expansion and merger of bubbles of the newly stable phase. The resulting sound waves would have been a powerful source of gravitational radiation, containing information about the thermodynamic parameters of the transition. I will review ongoing work on characterising the spectrum of gravitational radiation from early universe phase transitions and prospects for observing an electroweak-scale transition at the future space-based gravitational wave detector LISA.
12:25 Lunch Break
Lunch Break
12:25 - 13:55
Room: Ullandhaug Campus, AR Ø-110
13:55 Cracks in the standard cosmological model: Anomalies, tensions, and hints of new physics - Eleonora Di Valentino (U Sheffield)
Cracks in the standard cosmological model: Anomalies, tensions, and hints of new physics
- Eleonora Di Valentino (U Sheffield)
13:55 - 14:30
Room: Ullandhaug Campus, AR Ø-110 The ΛCDM model has long served as the standard paradigm in cosmology, offering a remarkably successful description of the Universe’s evolution. Yet, as observational precision continues to improve, persistent tensions have emerged across a range of probes, including the well-known Hubble constant discrepancy. While individual datasets may each align with ΛCDM, their collective interpretation reveals significant discordances that challenge the model’s internal consistency. In this talk, I will review the most prominent tensions in modern cosmology and assess their implications. I will present recent results pointing to hints of dynamical dark energy and interactions within the dark sector. I will also reflect on the growing influence of methodological choices, such as dataset selection and model assumptions, in shaping our cosmological conclusions.
14:30 Contributed Talks: Tuesday I
Tuesday I
14:30 - 15:30
Room: Ullandhaug Campus, AR Ø-110
Contributions

14:30 Heisenberg dynamics of quantum particle in curved spacetime - Otto Kong (NCU Taiwan)

14:50 Quantum measure in Regge calculus - Gabriele Gionti (Vatican Observatory)

15:10 When dimensions become quantum: Toward a new approach to quantum gravity - Mikolaj Myszkowski (U Southern Denmark)
15:30 Coffee Break
Coffee Break
15:30 - 16:00
Room: Ullandhaug Campus, AR Ø-110
16:00 Contributed Talks: Tuesday II
Tuesday II
16:00 - 17:00
Room: Ullandhaug Campus, AR Ø-110
Contributions

16:00 Late-time phase transitions in cosmological simulations - Øyvind Christiansen (Czech Academy of Sciences)

16:20 Cosmological first-order phase transitions with large bubbles: Beyond conformal fluid and flat spacetime - Lorenzo Giombi (U Helsinki)

16:40 Gravitational wave signals from cosmic strings with backreaction - Lasse Gerblich (U Cambridge)
17:00 Session on Future Challenges: Cosmology beyond ΛCDM - What should theory do next? (convener: Giulia Gubitosi)
Cosmology beyond ΛCDM - What should theory do next? (convener: Giulia Gubitosi)
17:00 - 18:00
Room: Ullandhaug Campus, AR Ø-110

19:30 Conference dinner: Conference dinner
Conference dinner
19:30 - 22:00
Wednesday, 3 June 2026
09:00 Primordial black holes: formation and statistics - Cristiano Germani (U Barcelona)
Primordial black holes: formation and statistics
- Cristiano Germani (U Barcelona)
09:00 - 09:35
Room: Ullandhaug Campus, AR Ø-110 I will present the latest understanding on black hole´s formation in an expanding universe and discuss the statistics of Type I black holes.
09:35 Probing the big bang with numerical relativity - Eugene Lim (King's College London)
Probing the big bang with numerical relativity
- Eugene Lim (King's College London)
09:35 - 10:10
Room: Ullandhaug Campus, AR Ø-110 I will talk about how numerical relativity is now being used to solve hitherto intractable strong gravity and highly complex systems in the early universe. As examples, I will discuss on how we are using numerical relativity to understand how inflation may or may not occur, and also how we are now using numerical relativity to probe the stability of compact extra dimensions.
10:10 Coffee Break
Coffee Break
10:10 - 10:40
Room: Ullandhaug Campus, AR Ø-110
10:40 Contributed Talks: Wednesday
Wednesday
10:40 - 12:20
Room: Ullandhaug Campus, AR Ø-110
Contributions

10:40 On the diversity of dwarf galaxies in multi-component dark matter scenarios - Jessica Lopez-Sanchez (CEICO Prague)

11:00 Non-linear dynamics during kination - Panagiotis Giannadakis (King's College London)

11:20 Real-time cosmology in relativistic N-body simulations - Alexander Oestreicher (U Southern Denmark)

11:40 Warp drive: A gedankenexperiment taken too far - Hamed Barzegar (ENS de Lyon)

12:00 Gravity and topological field theory - Eirik Svanes (U Stavanger)
12:20 Conference Wrap-Up
Conference Wrap-Up
12:20 - 12:30
Room: Ullandhaug Campus, AR Ø-110

12:30 Lunch Break
Lunch Break
12:30 - 14:00
Room: Ullandhaug Campus, AR Ø-110