Scientific Calendar Event

Description ICTP awarded its 2021 Dirac Medal and Prize to four physicists whose theoretical work underpinned the 2015 detection of gravitational waves generated by black holes. The 2021 Dirac Medallists are: Alessandra Buonanno, Max Planck Institute for Gravitational Physics, Germany Thibault Damour, Institut des Hautes Études Scientifiques (IHÉS), France Frans Pretorius, Princeton University, USA, Saul Teukolsky, Caltech and Cornell University, USA. The four physicists have received the medal for establishing the predicted properties of gravitational waves in the curvature of spacetime produced when stars or black holes spiral together and merge. Their work was essential for the detection of gravitational waves from these energetic astronomical events by the Laser Interferometer Gravitational-Wave Observatory (LIGO). Alessandra Buonanno is the second woman to receive the Dirac Medal in its nearly 40-year history. The feature article is available at:

The 2021 Dirac Medal and Prize Ceremony will take place on Thursday 14 July at 15.00 hrs in the Budinich Lecture Hall @ ICTP. An introduction to the work of the four Medallists will be given by Prof. Kip Thorne (online).

The programme synopsis follows:

Talk by Prof. Alessandra Buonanno on "Ever More Accurate Predictions of Black-Hole Dynamics and Gravitational Radiation"
Theoretical predictions of gravitational waveforms from binary systems composed of black holes and neutron stars have been instrumental in detecting and identifying nearly 100 astrophysical signals observed so far by the LIGO and Virgo collaboration. After briefly reviewing the main ideas of the analytical effective-one-body framework, I will examine the synergetic approach that successfully combines analytical and numerical relativity to produce the accurate waveform models employed to infer astrophysical, cosmological and fundamental physics information. Then, I will highlight the future of gravitational-wave astronomy with the opening of new frequency bands on the ground and in space, in the next decade, and discuss some of the theoretical challenges and opportunities to develop high-precision gravitational waves for generic two-body dynamics, so that the full discovery potential can be exploited.

Talk by Prof. Thibault Damour on "Black Hole Binary Dynamics from Classical and  Quantum Gravitational Scattering"
ABSTRACT: Gravitational wave signals from coalescing binary black holes are detected, and analyzed, by using large banks of template waveforms. The construction of these templates makes an essential use of the analytical knowledge of the motion and radiation of gravitationally interacting binary systems.  A new angle of attack on gravitational dynamics consists of considering (classical or quantum) scattering states. The Effective One-Body approach offers a useful framework for translating scattering data into bound-states information.
Modern amplitude techniques have recently given  interesting novel results. These results are reaching a level where subtle conceptual issues arise.

Talk by Prof. Frans Pretorius, on "Open Questions on the Dynamics of Black Holes"
Today we have a solid theoretical understanding of the dynamics of black holes, as predicted by general relativity, for the typical binary merger expected as an astrophysical source observable via gravitational waves. However, in more "extreme" situations, namely black holes that collide with ultrarelativistic velocities, and black holes that spin near the maximal limit allowed by general relativity, less is known, in some cases even qualitatively. In this talk I will discuss some of these open problems, and speculate about possible answers.

Talk by Prof. Saul Teukolsky on "The Coming Revolution in Computational Astrophysics" (online)
Large-scale computer simulations are increasingly crucial in explaining astrophysical phenomena. For the past 60 years, the dominant computer method for solving these kinds of equations has remained essentially unchanged. To keep up with continuing advances in observation, simulations will require more fidelity and higher accuracy.  One might think that with exascale machines becoming available in the next few years, this will be easy. I will explain why this is not true, and why current codes will not be able to use these machines efficiently. I will describe new methods for harnessing the power of such exascale computers to solve some of the largest problems in astrophysics, including general relativity.


For those who wish to participate online, please register in advance  at the following Zoom link:

After registering you will receive a confirmation email with the link to join.
All are welcome to attend!


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