Quantum error correction gives us a more general way of
thinking about geometry in this code language,” said Preskill, the Caltech physicist.
At the time, Hawking and
Thorne both believed that information was lost in black holes, while Preskill thought that it was impossible.
And yet, as Caltech's Preskill wrote in 2012, building
reliable quantum hardware is challenging because of the difficulty of controlling quantum systems accurately.
In 2015, Harlow, Preskill, Fernando Pastawski and Beni Yoshida found another holographic code,
nicknamed the HaPPY code, that captures more properties of AdS space.