Enhancement of the precision of phase estimation under the gravitational redshift
Phys. Rev. D 111, 126002 – Published 9 June, 2025
DOI: https://doi.org/10.1103/vkyj-txz3
Abstract
Photons propagating in curved spacetime are inevitably affected by gravitational redshift, which adds additional noise to the channel for the transmission of information and decreases the precision of phase estimation of quantum states. Theoretical and experimental results demonstrate that weak measurement and quantum measurement reversal can indeed be useful for battling against decoherence. In our scheme, we employ weak measurement and quantum measurement reversal to enhance phase estimation precision for single-qubit and two-qubit systems affected by gravitational redshift in both amplitude-damping and phase-damping channels. For some quantum states, we find a direct relationship between the quantum Fisher information of phase estimation and quantum coherence. Our results show that combining weak measurement with quantum measurement reversal significantly suppresses decoherence in these channels and improves the precision of phase estimation for quantum states affected by gravitational redshift. Under the maximum measurement strength, our scheme attains optimal precision of phase estimation while eliminating the influence of gravitational redshift in both quantum channels.
