### THE EINSTEIN MEDAL 2023 AWARDED TO LUC BLANCHET

*Luc Blanchet in September 2023.*

Credit: Jean Mouette /IAP-CNRS-SU

During the ceremony on October 4, 2023 at the University of Bern (Switzerland), the Albert-Einstein Society (Albert-Einstein Gesellschaft, AEG) awarded Luc Blanchet the Einstein Medal for the year 2023.

*Einstein medal.*

Credit: Albert Einstein Society

The Albert Einstein Medal has been awarded mostly every year since 1979 to people who have “rendered outstanding services” related to the work of Albert Einstein.

*Luc Blanchet with Prof. Philippe Jetzer, Department of Physics, University of Zurich, president of the scientific commitee.*

Credit: DR

This year it rewards the work of Luc Blanchet, emeritus research director at the Institut d’astrophysique de Paris (CNRS-SU), on the theory of gravitational waves emitted by binary systems of compact stars, made of either black holes or neutron stars. This theory plays an essential role for the detection and analysis of gravitational signals measured by the LIGO, Virgo and KAGRA terrestrial network of detectors. The theoretical result is used to analyze the signal observed by these detectors, and consists of an approximation of the equations of general relativity, called “post -Newtonian”, whose aim is to add the relativistic corrections to the famous Einstein quadrupole formula of 1918. The post-Newtonian approximation was recently pushed to high orders by Luc Blanchet and his team, notably Guillaume Faye and their former doctoral students Quentin Henry, François Larrouturou and David Trestini, allowing them to obtain unequaled precision. These developments will be crucial for the analysis of signals emitted by supermassive black hole binaries that will be detected by the future gravitational wave observatory Laser Interferometer Space Antenna LISA.

#### Links

Website of the Albert-Einstein Society of Bern

Luc Blanchet's presentation (PDF)

**Web writing:** Valérie de Lapparent

**Layout:** Jean Mouette

*October 2023*