Measuring complete quantum states with a single observable

Abstract

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.

11 pages, 6 figures

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Cited by in corpus (7)

• On the dynamics of initially correlated open quantum systems: theory and applications
• Single-Shot Quantum Process Tomography
• Controlling NMR spin systems for quantum computation
• Quantum state tomography using a single apparatus
• An overview on Single Apparatus Quantum Measurements
• Robustness of random-control quantum-state tomography
• Ancilla Assisted Quantum Information Processing: General protocols and NMR implementations