Discriminating between Lüders and von Neumann measuring devices: An NMR investigation
| Autor: | T. S. Mahesh, Abhishek Shukla, C. S. Sudheer Kumar |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Physics
Quantum Physics Degenerate energy levels General Physics and Astronomy Observable State (functional analysis) 01 natural sciences 010305 fluids & plasmas symbols.namesake Quantum state Qubit Quantum mechanics Black box 0103 physical sciences symbols 010306 general physics Degeneracy (mathematics) Von Neumann architecture |
| Zdroj: | Physics Letters A. 380:3612-3616 |
| ISSN: | 0375-9601 |
| DOI: | 10.1016/j.physleta.2016.09.004 |
| Popis: | Measurement of an observable on a quantum system involves a probabilistic collapse of the quantum state and a corresponding measurement outcome. L\"uders and von Neumann state update rules attempt to describe the above phenomenological observations. These rules are identical for a nondegenerate observable, but differ for a degenerate observable. While L\"uders rule preserves superpositions within a degenerate subspace under a measurement of the corresponding degenerate observable, the von Neumann rule does not. Recently Hegerfeldt and Mayato [Phys. Rev. A, 85, 032116 (2012)] had formulated a protocol to discriminate between the two types of measuring devices. Here we have reformulated this protocol for quantum registers comprising of system and ancilla qubits. We then experimentally investigated this protocol using nulear spin systems with the help of NMR techniques, and found that L\"uders rule is favoured. Comment: 6 pages,6 figures, updated with a few more calculations |
| Databáze: | OpenAIRE |
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