1. No-Go Theorems for Universal Entanglement Purification
- Author
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Zang, Allen, Chen, Xinan, Chitambar, Eric, Suchara, Martin, and Zhong, Tian
- Subjects
Quantum Physics - Abstract
An entanglement purification protocol (EPP) aims to transform multiple noisy entangled states into a single entangled state with higher fidelity. In this work we consider EPPs that always yield an output fidelity no worse than each of the original noisy states, a property we call universality. We prove there is no $n$-to-1 EPP implementable by local operations and classical communication that is universal for all two-qubit entangled states, whereas such an EPP is possible using more general positive partial transpose-preserving (PPT) operations. We also show that universality is not possible by bilocal Clifford EPPs even when restricted to states with fidelities above an arbitrarily high threshold., Comment: 5+20 pages, 2+1 figures
- Published
- 2024