Mixed-State Berry Curvature in quantum multiparameter estimations

• URL: http://arxiv.org/abs/2511.16215v1
• Date: Thu, 20 Nov 2025 10:37:55 GMT
• Title: Mixed-State Berry Curvature in quantum multiparameter estimations
• Authors: Xiaoguang Wang, Xiao-Ming Lu, Yunbo Zhang, Libin Fu, Shu Chen,
• Abstract summary: We introduce a mixed-state quantum curvature and find that it plays a key role in the field of precision estimations.<n>As an example, we obtain the exact expression of the Berry curvature for an arbitrary qubit state.
• Score: 4.222777412194584
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: For pure states, the quantum Berry curvature was well studied. However, the quantum curvature for mixed states has received less attention. From the concept of symmetric logarithmic derivative, we introduce a mixed-state quantum curvature and find that it plays a key role in the field of multi-parameter precision estimations. Through spectral decomposition, we derive the mixed-state Berry curvature for both the full-rank and non-full-rank density matrices. As an example, we obtain the exact expression of the Berry curvature for an arbitrary qubit state.

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