Collective motion in bacterial suspensions is scale-free - Benjamín Pérez-Estay; Vincent Martinez; Carine Douarche; Jana Schwarz-Linek; Jochen Arlt; Pierre-Henri Delville; Gail McConnell; Wilson C. K. Poon; Anke Lindner; Eric Clément (Proceedings of the National Academy of Sciences, 2026)