A paper by the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Director Ooguri Hirosi and Project Researcher Matthew Dodelson on the string theoretical effects outside the black hole photon sphere has been selected for the "Editors' Suggestion" of the journal Physical Review D. Their paper was published on March 24, 2021.
source https://phys.org/news/2021-03-theory-mystery-particles-black-hole.html