Chinese Physics B

Characterization and Robustness of Three-Qubit GHZ and W States via Quantum Tomography

Yu-Fan Zhang, Lan Zhong, Wen-Hao Zhang, Liu Ye, Dong Wang

Published Apr 20, 2026• 0 citations

Abstract

Abstract Reliable verification of multipartite entanglement is a prerequisite for quantum information processing. However, the interplay between statistical fluctuations and systematic errors in Quantum State Tomography (QST) often obscures genuine quantum correlations. In this work, we perform a numerical benchmarking of QST performance for three-qubit GHZ and W states under a comprehensive noise model that incorporates Poissonian counting statistics, random unitary perturbations, white noise, and source instability. Beyond standard fidelity analysis, we utilize entanglement negativity and residual entanglement to investigate how these states respond to different noise sources. Our results highlight the response characteristics of entanglement measures and fidelity to experimental imperfections. We provide a quantitative analysis of the robustness profiles for both states, noting the entanglement decay and the evolution of residual entanglement under local unitary noise. Furthermore, we establish that employing an overcomplete tomographic set provides a slight advantage in mitigating systematic errors compared to standard informationally complete schemes. These findings provide a useful reference for analyzing the potential impacts of measurement artifacts and genuine decoherence in experimental setups.

DOI: 10.1088/1674-1056/ae617c

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