DOI: 10.22331/q-2026-10-28-2251 ISSN: 2521-327X
Optimal phase estimation in the presence of correlated dephasing
Srijon Ghosh, Arkadiusz Kobus, Stanisław Kurdziałek, Rafał Demkowicz-DobrzańskiWe investigate optimal metrological protocols for phase estimation in the presence of correlated dephasing noise, including spin-squeezed state sensing strategies as well as parallel and adaptive protocols optimized using tensor-network-based numerical methods. The results are benchmarked against fundamental bounds obtained either via the latest quantum comb extension method or an optimized classical simulation method. We find that the spin-squeezed states offer practically optimal performance in the regime where phase fluctuations are positively correlated but can be outperformed by tensor-network-optimized strategies for negatively correlated fluctuations.