HET Seminar | Beni Yoshida, Perimeter Institute | "Decoding a black hole" | Jadwin A09

Tue, Jan 16, 2018, 2:30 pm
Jadwin 407 PCTS

It is commonly believed that quantum information is not lost in a black hole. Instead, it is encoded into non-local degrees of freedom in some clever way; like a quantum error-correcting code. In this talk, I will present two decoding procedures for reconstructing a quantum state from the Hawking radiation in the Hayden-Preskill thought experiment. The first procedure teleports the state thrown into the black hole to an outside observer by post-selecting on the condition that a sufficient number of EPR pairs remain undisturbed. The second procedure is deterministic and combines the previous idea with Grover’s search algorithm. As with the original (non-constructive) decoding scheme, the algorithms utilize scrambling, where the decay of out-of-time-order correlators (OTOCs) guarantees faithful state recovery. Decoding protocols also provide an ideal platform for laboratory experiments to measure out-of-time ordered correlation functions in a way which clearly distinguish unitary scrambling from decoherence. I will conclude by introducing an ongoing experiment in a small quantum system.