Quantum Fisher Information of a Single-Photon Subtracted Squeezed Vacuum under Postselected von Neumann Measurement
Hunduz Halemjan, Chang Guohao, Shangyun Liu +3 more
Abstract This paper mainly focuses on the optimization of the quantum Fisher information (QFI) for a single-photon subtracted squeezed vacuum (SPSSV) state within the framework of postselected von Neumann measurements. By utilizing the polarization and spatial degrees of freedom of the single-photon subtracted squeezed vacuum state as the measured system and the probe, respectively, the manipulation of the QFI is achieved via the probe state under standard postselected von Neumann measurement. The results demonstrate that a large QFI can invariably be obtained through the combinatory effects of the interaction strength and squeezing parameter, which characterizes the non-classical properties of the SPSSV state. The weak value is found to be crucial in increasing the QFI under weak interaction strength. Our findings clarify the weak-value amplification (WVA) effect on the QFI, thereby revealing the advantage of non-Gaussian states in information acquisition under postselected measurement. Meanwhile, this paper also presents the corresponding implementation scheme for optical experiments.
Chinese Physics B•Apr 24, 2026•0 citations