Mixed-state Berry curvature in quantum multiparameter estimations
Abstract
Abstract For pure states, the quantum Berry curvature has been 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.
Fields of Study & Subjects
Quantum Information and Cryptography
Quantum Mechanics and Applications
Quantum Computing Algorithms and Architecture
Publication details
- Journal / source
- Communications in Theoretical Physics
- Volume
- 78
- Issue
- 5
- Pages
- 055105–055105
- Publication date
- 4 February 2026