Non-Gaussian Quantum State Engineering with Postselected von Neumann Measurements

• URL: http://arxiv.org/abs/2509.24188v2
• Date: Tue, 30 Sep 2025 13:02:33 GMT
• Title: Non-Gaussian Quantum State Engineering with Postselected von Neumann Measurements
• Authors: Xiao-Xi Yao, Yusuf Turek,
• Abstract summary: We introduce a feasible protocol for generating non-Gaussian (nG) states via postselected von Neumann measurement.<n>We characterize the non-Gaussianity via Wigner function negativities and quantify entanglement using linear entropy and concurrence.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We introduce a feasible protocol for generating non-Gaussian (nG) states via postselected von Neumann measurement for continuous-variable quantum information processing. The method uses a two-level system coupled to a Gaussian pointer state through an observable $A$ with $A^{2}=\mathbb{I}$. By operating beyond the weak-coupling regime and selecting different pointer states -- squeezed, coherent, or vacuum -- allows generation of a wide range of nG states, including squeezed cat states, two-mode entangled cat states, approximate Bell states, and a continuum of intermediate nG states with considerable success probabilities. The properties of these states are widely tunable via the postselection-induced weak value and the measurement interaction strength. We characterize the non-Gaussianity via Wigner function negativities and quantify entanglement using linear entropy and concurrence. The protocol offers a scalable route to high-purity nG state engineering.

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