Truncated Photon

by Germain Tobar (Stockholm University)

Tuesday 29 Sept 2026, 10:00 → 11:00 Europe/Stockholm

AlbaNova A5:1041 - CoPS grupprum (AlbaNova Main Building)

Isak Cecil Onsager Rukan, Jan Gulla, and Johannes Skaar^*

^{Phys. Rev. Lett. 137, 033601 (2026)}

An elementary particle such as a photon cannot be cut in two pieces. Still it must be possible to truncate a photon with an optical shutter. The result is neither another photon nor a mix of a photon and a vacuum. Instead it is a superposition and mix of photon numbers up to infinity. This state is rather complicated, but nevertheless locally equivalent to a single photon or vacuum to the left and right, respectively, of a narrow transition region.