Quantum-error-correction-assisted quantum metrology without entanglement
Kok Chuan Tan, S. Omkar, Hyunseok Jeong · Physical Review A · 2019
In this article we study the role that quantum resources play in quantum-error-correction-assisted quantum metrology (QECQM) schemes. We show that there exist classes of such problems where entanglement is not necessary to retrieve noise-free evolution and Heisenberg scaling in the long time limit. Over short timescales, noise-free evolution is also possible even without any form of quantum correlations. In particular, for qubit probes, we show that whenever noise-free quantum metrology is possible via QECQM, entanglement-free schemes over long timescales and correlation-free schemes over short timescales are always possible.