New horizons for fundamental physics with LISA
Authors: Arun K. G. , Belgacem Enis , Benkel Robert , Bernard Laura , Berti Emanuele , Bertone Gianfranco , Besancon Marc , Blas Diego , Böhmer Christian G. , Brito Richard , Calcagni Gianluca , Cardenas-Avendaño Alejandro , Clough Katy , Crisostomi Marco , De Luca Valerio , Doneva Daniela , Escoffier Stephanie , Ezquiaga José María , Ferreira Pedro G. , Fleury Pierre , Foffa Stefano , Franciolini Gabriele , Frusciante Noemi , García-Bellido Juan , Herdeiro Carlos , Hertog Thomas , Hinderer Tanja , Jetzer Philippe , Lombriser Lucas , Maggio Elisa , Maggiore Michele , Mancarella Michele , Maselli Andrea , Nampalliwar Sourabh , Nichols David , Okounkova Maria , Pani Paolo , Paschalidis Vasileios , Raccanelli Alvise , Randall Lisa , Renaux-Petel Sébastien , Riotto Antonio , Ruiz Milton , Saffer Alexander , Sakellariadou Mairi , Saltas Ippocratis D. , Sathyaprakash B. S. , Shao Lijing , Sopuerta Carlos F. , Sotiriou Thomas P. , Stergioulas Nikolaos , Tamanini Nicola , Vernizzi Filippo , Witek Helvi , Wu Kinwah , Yagi Kent , Yazadjiev Stoytcho , Yunes Nicolás , Zilhão Miguel , Afshordi Niayesh , Angonin Marie-Christine , Baibhav Vishal , Barausse Enrico , Barreiro Tiago , Bartolo Nicola , Bellomo Nicola , Ben-Dayan Ido , Bergshoeff Eric A. , Bernuzzi Sebastiano , Bertacca Daniele , Bhagwat Swetha , Bonga Béatrice , Burko Lior M. , Compére Geoffrey , Cusin Giulia , da Silva Antonio , Das Saurya , de Rham Claudia , Destounis Kyriakos , Dimastrogiovanni Ema , Duque Francisco , Easther Richard , Farmer Hontas , Fasiello Matteo , Fisenko Stanislav , Fransen Kwinten , Frauendiener Jörg , Gair Jonathan , Gergely László Árpád , Gerosa Davide , Gualtieri Leonardo , Han Wen-Biao , Hees Aurelien , Helfer Thomas , Hennig Jörg , Jenkins Alexander C. , Kajfasz Eric , Kaloper Nemanja , Karas Vladimír , Kavanagh Bradley J. , Klioner Sergei A. , Koushiappas Savvas M. , Lagos Macarena , Poncin-Lafitte Christophe Le , Lobo Francisco S. N. , Markakis Charalampos , Martín-Moruno Prado , Martins C. J. A. P. , Matarrese Sabino , Mayerson Daniel R. , Mimoso José P. , Noller Johannes , Nunes Nelson J. , Oliveri Roberto , Orlando Giorgio , Pappas George , Pikovski Igor , Pilo Luigi , Podolský Jiří , Pratten Geraint , Prokopec Tomislav , Qi Hong , Rastgoo Saeed , Ricciardone Angelo , Rollo Rocco , Rubiera-Garcia Diego , Sergijenko Olga , Shapiro Stuart , Shoemaker Deirdre , Spallicci Alessandro , Stashko Oleksandr , Stein Leo C. , Tasinato Gianmassimo , Tolley Andrew J. , Vagenas Elias C. , Vandoren Stefan , Vernieri Daniele , Vicente Rodrigo , Wiseman Toby , Zhdanov Valery I. , Zumalacárregui Miguel 
Published: June 2022

The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about the fundamental theory of nature at play in the extreme gravity regime, where the gravitational interaction is both strong and dynamical. In this white paper, the Fundamental Physics Working Group of the LISA Consortium summarizes the current topics in fundamental physics where LISA observations of gravitational waves can be expected to provide key input. We provide the briefest of reviews to then delineate avenues for future research directions and to discuss connections between this working group, other working groups and the consortium work package teams. These connections must be developed for LISA to live up to its science potential in these areas.