Quantum metrology enhanced by repetitive quantum error correction

Quantum metrology enhanced by repetitive quantum error correctionIn sensing and metrology noise is a fundamental problem because it randomises the sensor and therefore limits its precision. Quantum information science has found different ways to reduce the impact of noise and one of these is quantum error correction. Typically, quantum error correction requires a significant overhead in qubits, one needs at least three qubits to encode and protect a single qubit against phase noise. But this overhead can be reduced when combining stable qubits for encoding with error prone qubits for sensing. This has been achieved experimentally in our recent work where a sensing electron spin is combined with a encoding nuclear spin and repeated error correction has been achieved in combination with sensing.