Source of qubit instability used to provide error correction

Ars Technica : Maintaining the value stored in a quantum bit, or qubit, is difficult because of the quantum interactions between the qubit and the surrounding environment. Most qubits have a lifetime of only a few milliseconds or less. An international team of researchers is now using the nearby sources of quantum noise as a form of error correction for qubits made from free electrons provided by nitrogen vacancies in diamond crystals. To help stabilize the free electrons in those qubits, their spins are coupled with the spins of the nitrogen nuclei. The new technique extends that coupling to nearby carbon atoms in the diamond. By encoding the value on the electron to the nitrogen nuclei as well as to neighboring carbon nuclei, when one of the particles develops an error, it could be corrected by checking the states of the other particles. The system was tested at room temperature, so dropping the system temperature should extend the lifetime of the qubit to several milliseconds. However, the manipulation of the electron state requires frequent pulses of laser light, which slow operations and might stress a cryogenic system.