Definition of "theoretician"

“They have numerically confirmed, perhaps for the first time, something we were fairly sure had to be true, but was still a conjecture — namely that the thermodynamics of certain black holes can be reproduced from a lower-dimensional universe,” says Leonard Susskind, a theoretical physicist at Stanford University in California who was among the first theoreticians to explore the idea of holographic universes.

2013 December 10, Ron Cowen, “Simulations back up theory that Universe is a hologram”, in Nature News‎, retrieved 2014-04-27