| 10/02/2025 |
Julien Billard |
Maxime Pierre |
Searching for Light Dark Matter with the future TESSERACT experiment at LSM |
The future TESSERACT (Transition Edge Sensor with Sub-Ev Resolution and Cryogenic Targets) experiment aims at searching for light Dark Matter candidates in the sub-GeV range down to the keV-scale from the Laboratoire Souterrain de Modane. To do so, it is being designed to be highly sensitive to both nuclear recoil DM (NRDM) and electron recoil DM (ERDM) interactions. Multiple target materials will be used, sharing identical readout using Transition Edge Sensors operated at 10 mK. In addition to maximizing sensitivity to a variety of DM interactions, this provides an independent handle on instrumental backgrounds. Three detector technologies will be implemented: HeRALD which will use superfluid helium-4 as a target material, SPICE which will use polar and scintillating crystals, and Ge/Si semiconductors that will be developed by the French TESSERACT collaborators. In this talk, I will give an overview of the design status of the future TESSERACT experiment, discuss its different detector technologies with an emphasis on the Ge/Si one currently being developed in the context of the Ricochet neutrino experiment, and will present the science prospect of the experiment.
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Institut de Physique des 2 Infinis de Lyon (IP2I), Lyon, France |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 24/02/2025 |
Luciano Rezzolla |
Gianfranco Bertone |
Binary Neutron Stars: from macroscopic collisions to microphysics |
I will argue that if black holes represent one the most fascinating implications of Einstein's theory of gravity, neutron stars in binary system are its richest laboratory, where gravity blends with astrophysics and particle physics. I will discuss the rapid recent progress made in modelling these systems and show how the gravitational signal can provide tight constraints on the equation of state and sound speed for matter at nuclear densities, as well as on one of the most important consequences of general relativity for compact stars: the existence of a maximum mass. Finally, I will discuss how the merger may lead to a phase transition from hadronic to quark matter. Such a process would lead to a signature in the post-merger gravitational-wave signal and open an observational window on the production of quark matter in the present Universe. |
Goethe University, Frankfurt, Germany |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 10/03/2025 |
Jonathan Gair |
Maxime Pierre |
Opportunities and challenges in SBI for future gravitational wave detectors |
Simulation based inference (SBI) is becoming increasingly important in the analysis of data from the current generation of ground-based gravitational wave detectors. Plans are well advanced for future generations of detector, on the ground, and also in space. These future detectors will pose many more challenges that will test the boundaries of what is possible with both classical and machine-learning based methods. In this talk, I will provide an overview of the current state of the art in SBI for gravitational wave inference, focussing in particular on the DINGO analysis package. I will then describe the many new challenges that future detectors will pose, focussing on the case of LISA, the planned space-based gravitational wave detector due for launch in the mid 2030s. I will describe the classical approaches that are being developed to tackle the LISA data analysis problem and highlight areas where SBI methods could play a critical role in addressing the outstanding problems. |
Max Planck Institute for Gravitational Physics
(Albert Einstein Institute), Potsdam, Germany |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 31/03/2025 |
Max Welling |
Gianfranco Bertone |
Can AI Change the Paradigm for Scientific Discovery? |
While Large Language Models and the race towards AGI have captured all the attention (and drama). However, AI is also disrupting the way we do science. By shifting as much work as possible from experiments to the digital domain we can dramatically accelerate our understanding and prediction of nature, and design of new molecules and materials with desired properties. Key recent successes include weather prediction, protein design and folding (for which the 2024 Nobel prize was awarded) and Machine Learned Force Fields for chemical simulations. These developments are fundamental to keep Moore's Law alive (better semiconductors), develop new drugs, develop new sustainable energy solutions (nuclear fusion, synthetic fuels, batteries) and remove the excess carbon dioxide from our atmosphere (Carbon Capture and Removal). In this talk I will give an overview of some of these developments and argue that Europe needs to invest in this area to stay competitive and leave a clean planet for our children. |
University of Amsterdam, The Netherlands |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 07/04/2025 |
Lucio Mayer |
Rodrigo Vicente |
The cosmic evolution of massive black hole binaries and their nuclear environment;
the fil rouge connecting galaxy formation, accretion disk physics and gravitational wave astronomy |
Massive black hole binaries emerge in galactic nuclei as a consequence of the dynamics of hierarchical structure formation. Understanding the pairing and binary sinking process until they enter the in-spiral phase governed by gravitational wave emission is thus tightly connected with understanding the physics of galaxy formation and evolution. It is a computationally daunting task involving a huge range of spatial and temporal scales. The rate of GW in-spiral events that LISA will detect as well as their properties cannot be predicted without modelling the preceding phases. I will present an overview of the challenges that numerical simulations and semi-analytical models are facing, hinting at a potential "last kiloparsec problem".
I will make the case for a new, different approach based on using machine learning to build multi-scale emulators replacing direct numerical simulations.
I will then move on to describe how the modelling of the GW in-spiral signal for sources in the LISA band requires accounting for the environmental perturbations induced by surrounding matter. In particular, I will show results from some of the first post-newtonian hydrodynamical simulations that quantify the phase-shift induced on in-spiral waveforms from the residual gas torques from the circumbinary disk in which the two black holes are evolving. Environmental perturbations leave the imprint of accretion disk physics on the waveforms, at a minimum in the form of a phase-shift, and most likely also through additional
complex higher frequency modulations, "dirty waveforms", which are caused by local fluctuations in the accretion flow dynamics the black holes. These effects must be understood as they can be
degenerate with deviation from General Relativity, and are also a unique probe of physics near
black holes for scales well below those accessible via electromagnetic waves. |
Department of Astrophysics, University of Zurich, Switzerland |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 14/04/2025 |
Jia Liu |
Youyou Li |
Our Universe in Simulation |
Ongoing and upcoming cosmological surveys—including the Simons Observatory, LiteBIRD, CMB-S4, Rubin LSST, Euclid, DESI, PSF, SPHEREx, and the Roman Space Telescope—will deliver observations of unprecedented precision. Joint analyses across these surveys will be essential for uncovering fundamental physics, including the nature of inflation, dark energy, dark matter, neutrino mass, and more. In this talk, I will discuss the opportunities, challenges, and strategies for simulating our universe across multiple wavelengths to realize these goals. |
Kavli IPMU, University of Tokyo, Japan |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 12/05/2025 |
Malcolm Fairbairn |
Youyou Li |
Galaxies, Axions, Gravitational Waves, Black Holes and More Galaxies |
While we have known for decades that lots of the matter in the Universe appears to be dark, we are getting tired of explaining to people that we don't know what all this dark sector stuff is! We learn more about the dark sector, both what it isn't and what it might be, using 1) new methods of observation and 2) new theoretical techniques. I will attempt to follow a dubious narrative arc describing a range of new observations and techniques that are telling us more about the Universe. |
King's College, London, UK |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 26/05/2025 |
Ana Achucarro |
Ben Freivogel |
Multifield inflation attractors, and detractors |
TBA |
Leiden Institute of Physics, Leiden University, NL |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 02/06/2025 |
Carlos Frenk |
Rodrigo Vicente |
Is LCDM still alive? |
The ``Lambda cold dark matter'' (LCDM) cosmological model (where
Lambda stands for Einstein's cosmological constant and CDM for cold
dark matter) is one of the great achievements in Physics of the past
forty years. Theoretical predictions formulated in the 1980s turned
out to agree remarkably well with measurements, performed decades
later, of the galaxy distribution and the temperature structure of the
cosmic microwave background radiation. Yet, these successes do not
inform us directly about the nature of the dark matter or the dark
energy which are the two cornerstones of the model. In recent years a
number of observations have suggested possible discrepancies with LCDM
both on large and small scales. On large scales results from the DESI
galaxy survey are inconsistent with Lambda and indicate instead an
evolving dark energy. On small scales, the abundance of satellite
galaxies in the Milky Way and the discovery of bright galaxies at very
early times by the James Webb Space telescope are often interpreted as
challenges to the standard model. After a brief historical overview of
how the model emerged, I will discuss and assess these discrepancies
and the prospects for answering the question posed in the title. |
Institute for Computational Cosmology, Durham University, UK |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 16/06/2025 |
Wenzer Qin |
Youyou Li |
Using cosmic dawn to look beyond Lambda-CDM |
Cosmic dawn and the epoch of reionization have the potential to unveil a
wealth of information about cosmology, with probes such as the James
Webb Space Telescope already yielding intriguing results. In this talk,
I will discuss two different ways in which we can leverage information
from these high redshift measurements to probe beyond Standard Model
physics. First, I will show how energy injection by dark matter affects
the environments in which the first stars form, and therefore impacts
the timing of their formation and consequent signals in 21cm cosmology.
Second, I will show how enhancements to the initial density
perturbations in our universe may give rise to black holes that are not
primordial but nonetheless form at high redshifts, which we dub
“not-quite primordial black holes”, and how this can be used to
constrain enhancements to the primordial power spectrum. |
Center for Cosmology and Particle Physics, New York University, US |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 23/06/2025 |
Claudia de Rham |
Gianfranco Bertone |
Positivity in the Sky |
I will discuss the subtle interplay between low-energy effective descriptions relevant for our “everyday experiments”, and their embeddings within an ultimate high energy completion, and how these notions are affected by gravity. I will then discuss low-energy scatterings including loops from the Standard Model in the presence of gravity and their imprints on the high energy Regge behaviour, highlighting the implications to other gauge fields and to the Weak Gravity Conjecture. |
Imperial College London, London, UK |
C4.174, GRAPPA, Science Park 904, Amsterdam |
| 26/06/2025 |
Scott A. Hughes |
Rodrigo Vicente |
High-precision waveforms with the small-mass-ratio limit |
Current gravitational-wave detectors are being upgraded, and plans are developing for future detectors with greater sensitivity over broader frequency bands. As instruments improve and develop, more cycles of sources’ gravitational waveforms will be measured with greater signal to noise ratio. Such higher fidelity measurements promise to teach us more about their sources and the nature of strong-field gravity — but only if theoretical modeling of these waves is able to match advances in the detectors. As we measure waveforms with better precision, the likelihood increases that systematic modeling errors will affect inferences about what we measure. In this talk, I will survey recent progress modeling waveforms from small-mass binaries. Such binaries, which exactly describe important low-frequency gravitational wave sources, also serve as a limit of the more general binary problem that can be modeled with very high precision. I will discuss the outstanding progress that has been made on this problem in recent years, and how what we learn in this limit can be combined with other binary modeling techniques to advance modeling for relativistic binaries in general. |
MIT Kavli Institute, MIT, US |
C4.174, GRAPPA, Science Park 904, Amsterdam |
