Work

Full-Counting Statistics and Quantum Information of Dispersive Readout with a Squeezed Environment

Year: 2026

Type: article

Abstract: Motivated by the importance of dispersive readout in quantum technology, we study a prototypical dispersive readout setup that is probed by a squeezed vacuum in a time-reversal-symmetric fashion. To this end, we develop a full-counting-statistics framework for dispersive readout and analyze its measurement information, accompanied by a generalized mean-field approach suitable to deal with nonunitary dynamics. Distinct from conventional input-output theory, our full-counting-statistics approach enables the direct calculation of arbitrary-order cumulants for the measured cumulative (i.e., time-integrated) photonic distribution while maintaining applicability to nonlinear systems. The corresponding Fisher information exhibits an exponential dependence on the squeezing parameter and a robustness against residual nonlinearity, which can even approach the quantum Fisher information, setting an upper limit. This Letter introduces a conceptually streamlined and computationally efficient framework for continuous quantum measurements, making it well suited for widespread adoption in quantum technologies.

Source: Physical Review Letters

DOI: 10.1103/2s1m-y9bd

Authors: Ming Li, JunYan Luo, Gloria Platero, Georg Engelhardt

Institutions: Southern University of Science and Technology, Zhejiang University of Science and Technology, Consejo Superior de Investigaciones Científicas, Instituto de Ciencia de Materiales de Madrid, Shenzhen International Quantum Academy

Language: English

Topic: Quantum Information and Cryptography

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: green

Funders: National Natural Science Foundation of China, Ministerio de Ciencia y Tecnología, Consejo Superior de Investigaciones Científicas

Awards: G3416086553, 耦合量子点系统中电荷输运的量子反馈控制研究, G961666421