Channel correlation effects on quantum Fisher information in channel parameter estimation

Abstract We explore the impact of channel correlations, resulting from consecutive uses of the channel, on the estimation of channel parameters. Specifically, we analyze the dynamics of quantum Fisher information (QFI) for correlation strength and coupling strength in a two-qubit system subjected to either a Random Telegraph (RT) noise channel or an Amplitude Damping (AD) noise channel. Our findings indicate that the correlation in the RT noise channel enhances the estimation precision of correlation strength but detracts from the precision of coupling strength estimation. However, the correlation in the AD noise channel exhibits a similar effect to that of the RT noise channel only in the initial stage of system’s evolution. In the long-term evolution, the correlation of the AD noise channel reduces the estimation precision of correlation strength but has no monotonic relationship with the estimation precision of coupling strength. Our study provides new insights into the effects of channel correlations on channel parameter estimation and has potential implications for controlling the precision of parameter estimation in quantum information processing.