  Quantum systems can be exploited for disruptive technologies but in practice
quantum features are fragile due to noisy environments. Quantum coherence, a
fundamental such feature, is a basis-dependent property that is known to
exhibit a resilience to certain types of Markovian noise. Yet, it is still
unclear whether this resilience can be relevant in practical tasks. Here, we
experimentally investigate the resilient effect of quantum coherence in a
photonic Greenberger-Horne-Zeilinger state under Markovian bit-flip noise, and
explore its applications in a noisy metrology scenario. In particular, using up
to six-qubit probes, we demonstrate that the standard quantum limit can be
outperformed under a transversal noise strength of approximately equal
magnitude to the signal, providing experimental evidence of metrological
advantage even in the presence of uncorrelated Markovian noise. This work
highlights the important role of passive control in noisy quantum hardware,
which can act as a low-overhead complement to more traditional approaches such
as quantum error correction, thus impacting on the deployment of quantum
technologies in real-world settings.
