A research team from Yokohama National University is exploring quantum memory that is resilient against operational or environmental errors.
To scale up a quantum computer based on superconducting qubits, scientists need to operate under a zero magnetic field. In their search to further the technology toward an fault-tolerant quantum computer, the research team studied nitrogen-vacancy centers in diamond. Nitrogen-vacancy centers hold promise in a range of applications including quantum computing. Using a diamond nitrogen-vacancy center with two nuclear spins of the surrounding carbon isotopes, the team demonstrated quantum error correction in quantum memory.
They tested a three-qubit quantum error correction against both a bit-flip or phase-flip error, under a zero magnetic field. The bit-flip or phase-flip errors can occur when there are changes in the magnetic field. To achieve a zero magnetic field, the team used a three-dimensional coil to cancel out the residual magnetic field including the geomagnetic field. This quantum memory is error-correction coded to correct errors automatically as they occur.
Previous research had demonstrated quantum error correction, but it was all carried out under relatively strong magnetic fields. This team is the first to demonstrate the quantum operation of the electron and nuclear spins in the absence of a magnetic field.
The team’s demonstration can be applied to the construction of a large-scale distributed quantum computer and a long-haul quantum communication network by connecting quantum systems vulnerable to a magnetic field, such as superconducting qubits with spin-based quantum memories. Looking ahead, the research team has plans to take the technology a step further. (Physics.org)
The paper has been published in the journal Communications Physics.