The best approximation of a given qubit state with the limited pure-state set. (5th February 2021)

• Record Type: Journal Article
• Authors: Zhang, Li-qiang; Yu, Deng-hui; Yu, Chang-shui
• Is Part Of: Journal of physics. Volume 54:Number 8(2021)
• Publication Date: 2021-02-05
• Subjects: best convex approximation -- quantum state preparation -- quantum coherence; Mathematical physics -- Periodicals; Statistical physics -- Periodicals; Quantum theory -- Periodicals; Matter -- Properties -- Periodicals; 530.105
• DOI: 10.1088/1751-8121/abdcd0
• Languages: English
• ISSNs: 1751-8113

Abstract

Abstract: The preparation of quantum states lies at the foundation in the quantum information processing. The convex mixing of some existing quantum states is one of the effective candidate. In this paper, we mainly study how a target quantum state can be optimally prepared by not more than three given pure states. The analytic optimal distance based on the fidelity is found. We also show that the preparation with more than four states can be essentially converted to the case with not more than four states, which can be similarly solved as the case with three states. The validity is illustrated by the comparison of our analytical and numerical results.