Category: News

As the detection of a stochastic gravitational wave background from the early universe becomes increasingly promising, signals from hypothetical first-order phase transitions are attracting growing interest. Predicting these signals often requires the solution of plasma dynamics at macroscopic scales, which, in turn, depends on the phenomena that characterize the phase transition at microscopic scales.  Therefore, various assumptions on distinctive scales and their separation are usually employed to enable concrete evaluations. 
This workshop aims to bring together researchers from both the microscopic and macroscopic communities to collaboratively address theoretical shortcomings and refine current gravitational wave spectral templates across different regimes.

1. Microscopic scales – Quantitative uncertainties affect the fundamental phase transition par
   Advancing gravitational wave predictions from cosmological first-order phase transitions parameters within minimal scenarios beyond the Standard Model, where a scalar field drives the symmetry-breaking mechanism.
2. Intermediate scales – Different approaches have been employed to describe the interactions between the scalar field and the plasma, including bubble wall dynamics and plasma viscosity. A key question is, e.g., whether the bubble wall runs away or reaches a terminal velocity.
3. Macroscopic scales – Several approximations are used to connect to large-scale phenomena during and after the phase transition, such as collisions between the bubbles, the development of turbulence, and the evolution of sound shells.

Workshop Website

LIGO’s discovery of gravitational waves in 2015 has led to a new era in astronomy. By the mid-2030s, we will be able to observe astrophysical gravitational-wave sources across multiple frequency bands, which will greatly advance our understanding of the physical Universe. Asymmetric binary systems will be a main source of gravitational waves, particularly in the multi-band era. The best way to model them is to expand Einstein’s field equations about the small mass ratio of the system. This use of perturbation theory in the relativistic two-body problem has been advanced in modern times by independent groups in different ways, which can make it difficult for the various approaches to be compared for consistency. Asymmetric binaries also bring about unique mathematical challenges in the statistical analysis of their gravitational-wave signals in detector data, as well as their broader characterisation in the active astrophysical environments where they typically form.

This week-long IMS workshop provides a chance for researchers from relevant communities to work together on solving the remaining challenges in the modelling and interpretation of gravitational waves from asymmetric binary systems. The workshop will be structured along three main themes: theory, computation, and science. Each theme will be addressed through a combination of invited talks and discussion sessions. The first of the invited talks in each theme will be a keynote talk that reviews the history and current status of research under that theme. Each subsequent talk will target a key challenge under each theme, and will be delivered by a leading expert on that specific topic. The discussion sessions will then expand upon the various topics covered by the invited talks, and will be chaired by relevant experts who will initiate and guide discourse among all the attendees of the workshop.

Organizing Committee

Co-chairs

Alvin Chua (National University of Singapore )
Soichiro Isoyama (National University of Singapore )
Josh Mathews (National University of Singapore )

Scientific Committee

Leor Barack (University of Southampton, UK)
Jonathan Gair (Max Planck Institute for Gravitational Physics, Germany)
Scott Hughes (Massachusetts Institute of Technology, USA)
Takahiro Tanaka (Kyoto University, Japan)

Workshop Website

Black hole perturbation theory has been a key driver of theoretical gravity research since the 1960s, illuminating aspects of quantum gravity, information theory, gravitational-wave science, and the fundamental nature of black holes. It has played a particularly important role in two areas: self-force theory, used to model asymmetric binaries such as extreme-mass-ratio inspirals; and ringdown studies of dynamical black holes, such as occurs after a black hole merger.

Historically, almost all work in these areas has focused on linear perturbations. However, motivated by the needs of precision gravitational-wave astronomy, nonlinear black hole perturbation theory has recently emerged as the new frontier of the field. This advent of high-precision modelling offers exciting prospects for linking the self-force and ringdown communities.

This workshop will bring together prominent experts and leading young scientists from the two communities to share methods, spark new collaborations, and investigate new ideas in black hole physics.

Due to limited space, registration will be moderated. Preference will be given to participants who wish to also attend the 2nd Annual Workshop on Self-Force and Amplitudes, which will be held 9-12 September 2025 at the University of Southampton.

Invited speakers

Marina De Amicis
Devin Becker
Swetha Bhagwat
Patrick Bourg
Vitor Cardoso
Gregorio Carullo
Marc Casals
Stefan Hollands
Neev Khera
Sizheng Ma
Lorenzo Kuchler
Benjamin Leather
Lorena Magana Zertuche
Zach Nasipak
Rodrigo Panosso Macedo
Christiana Pantelidou
Ariadna Ribes
Andrew Spiers
Samuel Upton

Workshop Website

The 1st UNDARK workshop which will be held in Tenerife during the week Sept 29 - Oct 2rd 2025. This workshop will focus on astrophysical probes of fundamental questions related to the dark universe, with a specific emphasis on radio wave observations, as well as their possible connections with gravitational wave detection. The meeting is organized in the context of the UNDARK project and it aligns with the observational and instrumental expertise of the Instituto de Astrofísica de Canarias (IAC) in microwave astronomy. 

This workshop aims to bring together leading researchers in radio astronomy, cosmology, astrophysics, and particle physics to discuss recent advancements, ongoing projects, and future directions in the search for the dark sector of the universe.

Registration, with the possibility of abstract submission, will be open on April 27. There will be no registration fee, and participation will be limited to a selected number of participants.

Workshop Website

This one-week TH-Institute (June 9-13, 2025) aims to bring together leading experts in nuclear physics, astrophysics, and particle physics to address the key questions surrounding the equation of state (EOS) of neutron star (NS) matter and its impact on multi messenger astronomy and new physics searches.

The EOS of neutron stars is crucial to understanding several astrophysical phenomena, from supernova explosions and neutrino emissions to gravitational wave signals from NS mergers. By examining the EOS and its interplay with standard model (SM) and beyond-standard model (BSM) physics, this event seeks to address questions like: What are the uncertainties in EOS modeling, and how can they be minimized to yield robust predictions? How do different EOSs affect GW signals and NS cooling mechanisms? How much different EOS impact constraints on new motivated particles, such as the QCD axion? What role does QCD EOS play in the formation of primordial black holes, and how can observations of NS mergers constrain new physics?

The TH-Institute will thus cover a range of topics, including:

Theoretical modeling of the EOS of NS matter and its observational implications
Neutrino emissions from young and old neutron stars, and their role in SN explosions
Gravitational wave signals from NS mergers and their sensitivity to the EOS
New physics searches in astrophysical environments, with a focus on axions, neutrinos, and gravitational waves

Registration: We welcome everyone interested in these topics to join us in-person or online. In-person participation will be moderated. Upon in-person registration confirmation we recommend arranging accomodation as soon as possible. The accomodation tab gives further information. Deadline for registration is April 30.

Workshop Website