Max Planck Institute for Gravitational Physics

• Geometry and Gravitation[11] (led by Lars Andersson) at AEI Potsdam. This research group studies fundamental questions in the theory of gravity and related physical theories with mathematical methods.
• Searching for Continuous Gravitational Waves[12] (led by M. Alessandra Papa) at AEI Hannover. This research group works on searches for as of today undetected continuous gravitational waves, which are expected from rapidly rotating neutron stars.

• Binary Merger Observations and Numerical Relativity[13] (led by Frank Ohme) at AEI Hannover. The independent research group works on gravitational-wave data analysis and predictions of wave forms for signals from merging black holes and neutron stars. The studies are based on numerical simulations of these processes.
• Exceptional Quantum Gravity (Emeritus group, led by Hermann Nicolai) at AEI Potsdam. This research group is funded by an ERC Advanced Grant. Its research is concerned with a symmetry-based approach to a consistent theory of quantum gravity.
• Historical Epistemology of the Final Theory Program[14] (led by Alexander Blum) at AEI Potsdam. This research group focuses on the history of the search for a quantum gravity theory. The group is a joint Max Planck Research Group of the Max Planck Institute for the History of Science in Berlin and the Max Planck Institute for Gravitational Physics in Potsdam.
• Multi-messenger Astrophysics of Compact Binaries[15] (led by Tim Dietrich) at AEI Potsdam. This Max Planck Fellow research group investigates the electromagnetic and gravitational-wave emission from binary neutron star mergers using numerical relativity methods.
• Theoretical Cosmology[16] (led by Jean-Luc Lehners) at AEI Potsdam. This research group is funded by an ERC Consolidator Grant and works on theoretical physics of the very early universe and the Big Bang.

At AEI Hannover and AEI Potsdam, there are two LIGO Scientific Collaboration groups concerned with theory and data analysis of the LIGO and Virgo detectors.[20][21] At AEI Hannover there is also the GEO group concerned with various experimental topics.[22] AEI researchers in Potsdam and Hannover analyse LIGO and Virgo data. They also develop predictions of gravitational-wave signals used for the search for mergers of black holes and neutron stars and their interpretation.

The AEI Hannover is a partner institution in the advanced LIGO project and contributed the pre-stabilized laser system[23][24][25] for the advanced LIGO detectors in Hanford and Livingston. AEI researchers help commissioning and operating the advanced LIGO interferometers.

In early 2018 researchers at AEI Hannover have developed, built, and helped install a squeezed-light source at the Advanced Virgo gravitational-wave detector.[26] During the third joint observation run of the gravitational-wave detectors, it reduced the quantum-mechanical background noise by about third, increasing the expected detection rate of binary neutron star mergers by up to 26%.[27][28]

Researchers at AEI contribute to the planning, development of, and the science case[29] for the Einstein Telescope (ET), a third-generation gravitational-wave detector in Europe. The ET steering committee co-chair is at AEI Hannover,[30] and laser technology for the ET Prototype in Maastricht is to be developed at AEI Hannover.[31] AEI Potsdam researchers contribute to developing wave-form models for third generation gravitational-wave detectors such as the Einstein Telescope.[32]

The GEO600 gravitational-wave detector south of Hannover was designed and is operated by scientists from the Max Planck Institute for Gravitational Physics and the Leibniz Universität Hannover, along with partners in the United Kingdom.[33]

LISA Pathfinder was a test mission by ESA for the Laser Interferometer Space Antenna (LISA). It demonstrated key technologies for gravitational-wave detection in space. The Max Planck Institute for Gravitational Physics in Hannover and the Institute for Gravitational Physics at Leibniz Universität Hannover were responsible for and coordinated the German contribution to the mission.[34]

During the operations phase, Max Planck and Leibniz Universität researchers in Hannover were partners in the mission's data analysis.[35] They also played a leading role developing the analysis software LTPDA, a MATLAB toolbox.[36] AEI scientist took part in the mission operations shifts at ESOC.

The space-based gravitational-wave observatory LISA is developed under ESA leadership in collaboration with a scientific consortium.[37] The LISA consortium is led by AEI director Karsten Danzmann.[37] At AEI Hannover and AEI Potsdam there are LISA Consortium groups.[38] At AEI Hannover there are large laboratories for LISA laser interferometry experiments.[39]

GRACE-FO is a satellite-based geodesy mission that takes detailed measurements of the Earth's gravitational field and its temporal and spatial variations by interferometric distance measurements between two satellites. The laser ranging interferometer used for this purpose is a cooperation between NASA and German partners, with the German contribution led by the AEI. The instrument's concept, its prototypes and technical specifications were done at the AEI. AEI researchers have been involved in developing and testing the flight hardware.[40]

The institute's outreach activities include Open Days at the AEI Potsdam and at the GEO600 gravitational-wave detector, participation in the Girls' Days and Future Days, popular science talks by researchers,[46] participation in the “November der Wissenschaft” in Hannover,[47] tours of the institutes including selected laboratories and computer clusters, and a program for visits and presentations by researchers at high schools.[48]

The institute runs the popular-science webportal Einstein Online,[49] which is a hypertext network with introductory and in-depth articles about Einstein's theory of relativity and its consequences.

Since 2018, the institute has been offering a Journalists-in-Residence program to science journalists. The goal is to improve the communication between journalists and scientists, and to provide deeper insight into the institute's research.[50]

The institute together with the University of Wisconsin–Milwaukee is one of the two host institutions of the distributed volunteer computing project Einstein@Home.[51] Einstein@Home aggregates computing time on volunteers’ computers to search for signals from rotating neutron stars in data from the LIGO gravitational-wave detectors, from large radio telescopes, and from the Fermi Gamma-ray Space Telescope.