Gravity from Particle Amplitudes is a research group based at the Niels Bohr International Academy and affiliated with the Theoretical Particle Physics and Cosmology group at the Niels Bohr Institute, University of Copenhagen. Our interdisciplinary research builds on the two pillars of theoretical physics in gravity and particle physics.

Measurements of gravitational waves by the LIGO/Virgo and upcoming detectors open up the exciting possibility of testing theories of gravity, including the regime of strong gravity as probed by black holes just prior to merging. Analytical advances are required in order to push theory to the level where it can provide best-fit templates from which physical parameters can be extracted from data. To this end, our group develops and implements ideas and methods from quantum field theories, and especially from particle scattering amplitudes.

Our research activities are supported by funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreements No. 764850 `SAGEX' and No. 847523 `INTERACTIONS'; the private Danish foundations: Carlsberg and Lundbeck foundations; and the University of Copenhagen.

Particle amplitudes are the arena where quantum field theory (QFT) directly confronts experiment, for which a precise understanding of the theory is crucial. At the same time, studies of particle amplitudes have revealed in recent years that our fundamental understanding of QFT is far from complete. Due to numerous intriguing relations of gauge theories to gravity, it is obvious that we must investigate how these modern advances in QFT translate into a better understanding of gravity.

Our understanding of gravity is not only lacking at the quantum regime, but also at the classical one. In fact, the problems we have with gravity in the UV and the IR sides, may well be tied together. A plethora of candidate theories of gravity has been put forward along the years, both classical and quantum. The growing developments in gravitational-wave measurements may largely benefit our ability to pin down the ultimate viable theory of gravity across quantum and classical scales.

The unique use of QFT concepts and methods in gravity, that is realized in our research group, bridges the gap between traditionally disparate domains in theoretical physics, and makes these ideas and tools widely accessible to the community. As this research demonstrates the universality of many of these methods, and exposes commonalities across classical and quantum field theories, the power and potential of using QFT advances to study gravity and gravitational radiation has become widely recognized.

Within this school of thought our group has pioneered research themes as:

• Perturbative quantum gravity as an effective field theory (EFT).
  
• High-precision post-Newtonian and post-Minkowskian gravity.
• Spin and higher-spin in gravity theories from EFT.
• Direct connection of gauge-invariant observables in gravity.
• EFTs from amplitudes for higher-spin in gravity.

Group Members

Faculty
Michèle Levi, Assistant Professor
Emil Bjerrum-Bohr, Associate Professor
Poul Henrik Damgaard, Professor
Fellows & Students
Humberto Gomez, Postdoctoral Fellow
Andrew McLeod, Postdoctoral Fellow
Matthew von Hippel, Postdoctoral Fellow
Andrea Cristofoli, PhD Fellow
Kays Haddad, PhD Fellow
Andreas Helset, PhD Fellow
Anagha Vasudevan, PhD Fellow
Roger Morales, MSc Student
Edwin Vargas, MSc Student
Mariana Vieira, MSc Student

Affiliates

Stavros Mougiakakos, PhD Student            IPhT Saclay, U. of Paris-Saclay

2020

• Harald Pfeiffer (Albert Einstein Institute), Mar. 2020

2019

• Fei Teng (Uppsala University), Dec. 2019
• Silvia Nagy (U. of Nottingham), Dec. 2019
• Jung-Wook Kim (Seoul National University), Nov. 2019
• Donal O'Connell (U. of Edinburg), Oct. 2019
• Henrik Johansson (Uppsala University & Nordita), Oct. 2019
• Brando Bellazzini (IPhT Saclay), Oct. 2019

Michèle Levi, Assistant Professor

Email:  michelelevi@nbi.ku.dk