Unlike other qubits, qubits in the cat state cannot undergo phase flips, so engineers building quantum computers based on them need only worry about bit flips, as they do with conventional computers. I have. Researchers are currently investigating how to use these cat-state qubits to perform computations.
Here, Ye-Hong Chen and four collaborators at the RIKEN Quantum Computing Center use cat states to realize fault-tolerant gates that connect multiple qubits in a process known as entanglement. The method has been theoretically demonstrated.
“Conventional computers could only process one bit of data at a time, but entanglement allows quantum computers to process large amounts of data simultaneously,” Chen explains. “Gates can quickly generate entangled cat states with high accuracy.”
The team showed that such fault-tolerant quantum gates can be used to implement highly efficient quantum search algorithms. This algorithm will allow databases to be searched faster than is currently possible using conventional computers.
“Let’s say you want to find one key out of 100 keys that opens a box. Identifying the one key that opens that box takes, on average, 50 keys using a conventional search algorithm. I have to try the key,” says Chen. “But with the quantum search algorithm, the average number of trials is only 10,” Chen says.
The team is currently exploring ways to develop other useful quantum algorithms based on fault-tolerant quantum code.
