Hao Guo

Uhlmann Geometry of Fixed-Rank Density Matrices: A Fiber-Bundle Approach

For full-rank density matrices the state space is contractible, the Uhlmann bundle is topologically trivial, and the holonomy admits no quantized invariants; although the Uhlmann phase is genuinely geometric, this topological poverty has kept it from serving as a robust physical diagnostic of mixed-state matter. Mixed...