John Wheeler supervised more Ph.D. theses than any Princeton physics professor. They included
Richard Feynman, one of the architects of quantum electrodynamics (QED), and
Hugh Everett III, inventor of the "universal wave function" and the "relative state" formulation of quantum mechanics, later known as the "many-worlds" interpretation.
In the late 1930's, Wheeler worked with
Neils Bohr to show that it was U
235 that is the fissionable element in Uranium, pointing the path to the atomic bomb. (Wheeler became a great promoter of atomic and later nuclear weapons, encouraging their use against the Soviet Union to destroy communism.)
After World War II, Wheeler collaborated with Feynman to argue for the existence of incoming spherical electromagnetic waves (the so-called "advanced" potential). As early as 1905,
Albert Einstein argued against outgoing spherical waves (the normal "retarded" potential) and argued for light being large numbers of discrete "light quanta" (later called photons)..
Wheeler was a great contributor to many of the new discoveries in astrophysics and cosmology, especially gifted at naming them, e.g., "Black Hole," "Worm Hole," "It from Bit," and "Delayed Choice."
In 1978 Wheeler published a long paper titled '
The "Past" and the "Delayed Choice" Double-Slit Experiment.'
In it, Wheeler wrote
Can one choose whether the photon {or electron)
shall have come through both of the slits, or only one of
them, after it has already transversed this screen? [p.9]