  This study investigates the use of orbital angular momentum (OAM) to enhance
phase estimation in Mach-Zehnder interferometers (MZIs) by employing
non-Gaussian states as input resources in the presence of noise. Our research
demonstrates that non-Gaussian states, particularly the
photonsubtraction-then-addition (PSA) state, exhibit the best sensitivity in
the presence of symmetric noise. Additionally, higher-order of Bose operator of
non-Gaussian states provide better sensitivity for symmetric noise. OAM can
mitigate the deterioration of noise, making it possible to estimate small phase
shifts theta close to 0. OAM enhances the resolution and sensitivity of all
input states and mitigating the deterioration caused by photon loss.
Additionally, OAM enhances the resolution and sensitivity of all input states,
enabling the sensitivity to approach the 1/N limit even under significant
photon loss (e.g.,50% symmetric photon loss). These results hold promise for
enhancing the sensitivity and robustness of quantum metrology, particularly in
the presence of significant photon loss.
