Quantum Fisher Information for Density Matrices with Arbitrary Ranks

By Jing Liu, Xiaoxing Jing, W. Zhong, Xiaoguang Wang. 2013

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We provide a new expression of the quantum Fisher information (QFI) for a general system. Utilizing this expression, the QFI for a non-full rank density matrix is only determined by its support. This expression can bring convenience for an infinite-dimensional density matrix with a finite support. Besides, a matrix representation of the QFI is also given.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/7c616872ea1ebfd624048487343c32549fc4e8e9