4 papers
Gaussian Fisher Information Is Superadditive
Jiaxin Liu, Zuoxian Wang, Danyue Ma
Quantum Fisher information adds over independent probes, so a single parameter is best measured probe by probe. We show that Gaussian measurements, the linear optics and homodyne d…
Record Loss Sets a Rare-Trajectory Limit on Quantum Purification
Jiaxin Liu, Zuoxian Wang, Feng Li +1
Continuous quantum feedback uses time-resolved measurement records to steer monitored systems toward pure states. Yet how the information available to a controller determines the u…
Efficiency-Induced Freezing in Quantum-State Purification
Jiaxin Liu, Zuoxian Wang, Feng Li +1
Any nonzero detection loss qualitatively changes feedback-controlled purification under diffusive monitoring. In every finite dimension, we prove a sharp, dimension-independent cei…
Entanglement Drives Common Noise into the Strong-Coupling Regime
Jiaxin Liu, Yizhe Zhou, Xing Heng +3
Under Gaussian collective dephasing parallel to the signal, the superdecoherence of an -atom Greenberger--Horne--Zeilinger (GHZ) state cancels its gain in Fisher information, so…