Penn Researchers Demonstrate Room-Temperature Diamond System That Entangles Four Qubits 10 Times Faster

Insider Brief

• Researchers entangled four qubits in a room-temperature diamond system about 10 times faster than with a conventional sequence of two-qubit gates.
• The parallel gate completed the operation in 14.8 microseconds with a fidelity of 0.92, compared with 0.69 for the sequential method.
• The approach could support more sensitive quantum sensors and more efficient error correction, but it remains a four-qubit laboratory demonstration.

Researchers have entangled four qubits inside a diamond at room temperature using a single gate, cutting the operation time by about 90% while improving its accuracy over the conventional approach.

The experimental system produced a four-qubit entangled state in 14.8 microseconds, which researchers report was about 10 times faster than a sequence of two-qubit gates. According to the study published in Nature Nanotechnology, the parallel gate achieved a fidelity of 0.92, meaning its operation closely matched the intended result. The conventional method, which entangled the qubits two at a time through a series of separate operations, achieved a fidelity of 0.69.

The findings could lead to more capable room-temperature quantum sensors and more efficient error correction in solid-state quantum processors. They also demonstrate a way to turn unwanted interactions among qubits, normally treated as a source of errors, into a tool for controlling several qubits simultaneously.