The Simons Foundation provides eight million US dollars to fund a worldwide collaboration on black holes and strong gravity

The Max Planck Institute for Gravitational Physics in Potsdam is part of the network aiming to decipher the secrets encoded in gravitational-wave data.

The newly funded Simons Collaboration on Black Holes and Strong Gravity will support the work of 12 institutions, bringing together experts in gravity and black holes from theoretical physics, mathematics, numerical computation, AI-assisted data analysis and gravitational wave observation. Moving toward the era of precision gravitational wave physics, the multidisciplinary effort will deepen our understanding of non-linear gravity. The collaboration will develop a robust theoretical framework for interpreting the information about strong gravity encoded in gravitational-wave data, including the matter–antimatter asymmetry of the universe, the nature of dark matter and potential extensions to Einstein's theory of general relativity.

“Once the planned upgrades to the Advanced LIGO/Virgo/KAGRA gravitational-wave detectors have been installed over the next few years, these instruments' sensitivity will double. This will increase the volume of the universe accessible to us through gravitational-wave data by a factor of eight,” says Jonathan Gair, Principal Investigator (PI) of the new collaboration and group leader in the Astrophysical and Cosmological Relativity department at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in the Potsdam Science Park.

The greater sensitivity of gravitational-wave detectors will enable more precise measurements which will offer sensitivity to new physical effects. However, these can only be identified if accurate models of the effects are available. Models that fail to correctly account for effects that the signals could contain may lead to potential discoveries being missed or misinterpreted. Examples of effects that could be mismodelled are the presence or absence of deviations in the theory of gravity from general relativity, instrumental artefacts and noise fluctuations in the detector, and the signatures of astrophysical environments such as an accretion disk or the presence of a third astrophysical body in the vicinity of a black-hole merger.

“Our goal is to predict possible new physical effects as precisely as possible so that we are in a position to decipher the secrets hidden within the observations,” says Gair. “Our research focus at AEI will be to understand what is measurable from a practical perspective and how to do it. We’ll be working with some of the other PIs to develop flexible, model-free searches for new physics and how to interpret the results of such flexible analyses in terms of the underlying physical process that are triggering them.”

Probing the physics of strong gravity

Gravity is one of the pillars of theoretical physics. The researchers in the new collaboration will work to understand gravity in the most dynamic and violent astrophysical environments, when black holes collide, and gravity is dynamical and strongly nonlinear. Understanding gravity in this extreme environment can reveal a lot about nature and probe Einstein’s general relativity.

Nicolás Yunes, physics professor at the University of Illinois, who will serve as the collaboration’s director, says the time to build this global network of multidisciplinary strong-gravity and black-hole experts is now, as gravitational-wave observational capabilities are rapidly advancing. “We’re moving toward the era of precision gravitational wave physics,” comments Yunes. “This new era must be accompanied by a multidisciplinary effort to deepen our understanding of non-linear gravity. Otherwise, we will miss secrets encoded in the gravitational wave data, or worse, misinterpret our observations and be led in the wrong direction.”

The Simons Collaboration on Black Holes and Strong Gravity

For an initial period of four years, the $8 million grant will bring together 12 Principal Investigators from 12 institutions, as well as researchers from over 20 additional institutes, enlisting the expertise of physicists, mathematicians, and data scientists. At the AEI, the Associate Members are Alessandra Buonanno, director of the Astrophysical and Cosmological Relativity department, and Masaru Shibata, director of the Computational Relativistic Astrophysics department. The collaboration will perform analytical calculations and run computer simulations, testing these against observations. The grant will provide postdoctoral and graduate student support, as well as funding for travel between member institutions and for various meetings each year.

Institutions involved in the new collaboration are:

• the University of Illinois;
• the Johns Hopkins University;
• the Queen Mary University of London;
• Montana State University;
• the Max Planck Institute for Gravitational Physics;
• the Niels Bohr Institute, University of Copenhagen;
• the University of Chicago;
• the University of California, Santa Barbara;
• the Perimeter Institute of Theoretical Physics;
• the Vanderbilt University;
• the Institute for Advanced Study;
• Princeton University

The Simons Foundation and the Simons Collaborations

The Simons Foundation was established in 1994 by the mathematician and hedge fund manager James Simons and his wife, Marilyn. It is one of the largest charitable organizations in the United States and is dedicated to promoting mathematical and basic scientific research.

The aim of the Simons Collaborations in the Mathematics and Physical Sciences program is to stimulate progress on fundamental scientific questions of major importance in mathematics, theoretical physics and theoretical computer science.