The Strong Fields, Integrability and Strings programme, which took place at the Isaac Newton Institute, explored an area that would have been close to Isaac Newton’s heart: how to unify Einstein’s theory of gravity, a continuation of Newton’s own work on gravitation, with quantum field theory, which describes the atomic and sub-atomic world, but cannot account for the force of gravity. The strongest contender for such a unified theory of quantum gravity is string theory, but to date string theory remains purely theoretical – it cannot be tested in the laboratory and its relation to other areas of physics is unclear.
The programme set out to explore a remarkable breakthrough made by the physicist Juan Maldacena in the late 1990s. String theory and quantum field theory had traditionally been separate areas within physics, but Maldacena proposed an exact mathematical correspondence between the two. This result, known as the AdS/CFT correspondence, suggests that the two theories are in fact equivalent, and opens up tantalising possibilities: perhaps long-standing problems from one theory can be translated into problems in the other, where they might be easier to solve. The technique promises to shed light on a range of fundamental physical questions, from the beginning of the Universe to a precise mathematical understanding of particle physics.