Physics Research Conference

More than forty years ago Hawking showed that black holes do not only absorb matter and energy but also radiate as black bodies with a certain temperature. However, Hawking's semiclassical theory is at odds with unitarity, which implies that information contained in infalling objects should eventually come out. We currently have a partial solution to this puzzle, and sharpening it might help to construct a fully quantum theory of gravity. The basic picture of interaction between incoming and outgoing particles and the resulting information exchange involves out-of-time-order correlators (OTOCs) of quantum observables. Such correlators can also be defined for more conventional systems, e.g. a chunk of metal, but the black hole OTOCs are special in certain ways. I will describe a quantum Hamiltonian, known as the Sachdev-Ye-Kitaev model, that has very similar OTOCs. Furthermore, this 0+1-dimensional model has a collective mode that is equivalent to dilaton gravity in 1+1 space-time dimensions.