Optimal phase estimation in the presence of correlated dephasing

TL;DR

This paper explores optimal quantum metrology strategies for phase estimation under correlated dephasing noise, comparing spin-squeezed states and tensor-network optimized protocols, revealing their relative effectiveness depending on noise correlation.

Contribution

It introduces tensor-network based optimization for phase estimation protocols and benchmarks their performance against traditional spin-squeezed states and classical bounds.

Findings

Spin-squeezed states perform well with positively correlated noise.

Tensor-network strategies outperform spin-squeezed states with negatively correlated noise.

Benchmarking against fundamental bounds validates the effectiveness of proposed protocols.

Abstract

We investigate optimal metrological protocols for phase estimation in the presence of correlated dephasing noise, including spin-squeezed states 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 a latest quantum comb extension method or an optimized classical simulation method. We find that the spin-squeezed 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.