At last year’s big annual string theory meeting, the Stanford University string theorist Eva Silverstein was amused to find she was one of the few giving a talk “On string theory proper,” she said.
Even as string theory’s mathematical tools get adopted across the physical sciences, physicists have been struggling with how to deal with the central tension of string theory: Can it ever live up to its initial promise? Could it ever give researchers insight into how gravity and quantum mechanics might be reconciled – not in a toy universe, but in our own?
One high point for string theory as a theory of everything came in the late 1990s, when Maldacena revealed that a string theory including gravity in five dimensions was equivalent to a quantum field theory in four dimensions.
You start with a simplified type of quantum field theory that behaves the same way at small and large distances, said David Simmons-Duffin, a physicist at the IAS. If these specific kinds of field theories could be understood perfectly, answers to deep questions might become clear.
“String theory is a much less rigorously constructed set of ideas than quantum field theory, so you have to be willing to relax your standards a bit,” he said.
The infinite landscape of possible universes can be directly linked to “The rich structure that we find in string theory,” she said – the innumerable ways that string theory’s multidimensional space-time can be folded in upon itself.
“Once the elementary things we’re probing spaces with are strings instead of particles,” said Beem, the strings “See things differently.” If it’s too hard to get from A to B using quantum field theory, reimagine the problem in string theory, and “There’s a path,” Beem said.