Fig. 2: The sensing scheme with QEC.
From: Quantum-enhanced radiometry via approximate quantum error correction
a Quantum circuit of the sensing scheme without QEC. After the encoding process, the probe evolves freely for an interrogation time tint, and is read out through detection of the ancilla following a decoding process. b Scheme for the QEC-enhanced sensing with the interrogation interleaved with QEC operations. The QEC operation consists of a QEC pulse and detection and a conditional reset of the ancilla. The interrogation time is tint in a and tint = Mτint in b, with M from 1 to 10 being the repetition number of QEC. c Measurement results of Pg without QEC for the probe state \(|{\psi }_{1,3}\rangle =(\left|1\right\rangle +{e}^{i{\varphi }_{0}}\left|3\right\rangle )/\sqrt{2}\) against the initial phase φ0 and with tint ranging from 0.1T1 to T1. d Performance of the QEC-enhanced sensing for the same probe state with an optimized interval τint = 0.1T1. The shift of fringes with the increasing M is mainly caused by the QEC-induced phase.
