Physicists create ‘smallest, clumsiest hole imaginable’
“We make uncertainty an ally and embrace it,” said Dr Spiropoulou.
To reach their full potential, quantum computers will need thousands of working qubits and another million “error-correcting” qubits. Google hopes to achieve such a goal by the end of the decade, according to Hartmut Neven, head of the company’s Quantum Artificial Intelligence Laboratory in Venice, California, who is also on Dr. Spiropoulou’s team.
Caltech physicist and Nobel laureate Richard Feynman once predicted that the ultimate use of this quantum power might be to probe quantum physics itself, as in the wormhole experiment.
“I’m excited to see that researchers can live out Feynman’s dream,” said Dr. Neven.
The wormhole experiment was performed on a version of Google’s Sycamore 2 computer, which has 72 qubits. Of these, the team used only nine to limit the amount of interference and noise in the system. Two were reference qubits that played the role of input and output in the experiment.
The seven other qubits contained the two copies of the code describing a “watered-down” version of an already simple model of the holographic universe called SYK, named after its three creators: Subir Sachdev of Harvard, Jinwu Ye of Mississippi State University, and Alexey Kitaev of Caltech. Both SYK models were packed into the same seven qubits. In the experiment, these SYK systems played the role of two black holes, one by encoding the message into nonsense—the quantum equivalent of swallowing it—and then the other by popping it back out.
“We’re throwing a qubit into that,” Dr Liken said, referring to the input message – the quantum analogue of a series of ones and zeros. This qubit interacts with the first copy of the SYK qubit; its meaning was mixed up in random noise and disappeared.
Then, in a quantum clock ticking, the two SYK systems were connected and a shock of negative energy passed from the first system to the second, briefly opening the latter.
The signal then reappeared in its original unencoded form – in the ninth and final qubit attached to the second SYK system, which represented the other end of the wormhole.