State interrogation in nuclear magnetic resonance quantum-information processing
- Department of Chemistry, University of California, Riverside, California 92521 (United States)
Reconstruction of a reduced density operator for weakly coupled systems of spins (1/2) from fits to nuclear magnetic resonance spectra is described in detail. Particular emphasis is placed on data treatment procedures that specify fewer than the 3{sup n} complete spectra that are implicitly prescribed in published references to state tomography on n-spin systems. It is shown that if the density operator is expanded in the so-called product-operator basis, it is always possible to estimate a desired coefficient in the expansion by measuring a single spectral multiplet. This simple observation can substantially reduce the experimental effort required for either complete density-matrix reconstruction or estimation of subsets of the coefficients in the product-operator expansion. A simple iterative algorithm can be used to produce reduced measurement procedures for experiments involving small numbers of qubits.
- OSTI ID:
- 20641115
- Journal Information:
- Physical Review. A, Vol. 69, Issue 5; Other Information: DOI: 10.1103/PhysRevA.69.052302; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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