Question: In string theory, D-branes are a class of extended objects upon which open strings can end with Dirichlet boundary conditions, after which they are named, D-branes were discovered by Dai, Leigh and which American theoretical physicist, and string theorist?
Sentence (from "String theory"): In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force.
Relevant evidence: No