2007/10/18 by Xinhua Peng, Jiangfeng Du, Dieter Suter
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum and electron transport phenomena #quant-ph
paper · pdf · doi:10.1103/physreva.76.042117
published as Physical Review A 76, 042117 (2007) · 11 pages, 6 figures
openalex publication_date 2007/10/18 · arxiv created 2008/03/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Experimental determination of an unknown quantum state usually requires several incompatible measurements. However, it is also possible to determine the full quantum state from a single, repeated measurement. For this purpose, the quantum system whose state is to be determined is first coupled to a second quantum system (the ``assistant'') in such a way that part of the information in the quantum state is transferred to the assistant. The actual measurement is then performed on the enlarged system including the original system and the assistant. We discuss in detail the requirements of this procedure and experimentally implement it on a simple quantum system consisting of nuclear spins.