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Nuclear-magnetic-resonance quantum calculations of the Jones polynomial

Journal Article · · Physical Review. A
; ; ; ;  [1];  [2];  [3];  [4];  [5]
  1. Department of Chemistry, Technische Universitaet Muenchen, Lichtenbergstr. 4, D-85747 Garching (Germany)
  2. Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115 (United States)
  3. University of Illinois at Chicago, 851 S. Morgan Street, Chicago, Illinois 60607-7045 (United States)
  4. University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States)
  5. Cruft Laboratory, Harvard University, 19 Oxford Street, Cambridge, Massachusetts 02138 (United States)

The repertoire of problems theoretically solvable by a quantum computer recently expanded to include the approximate evaluation of knot invariants, specifically the Jones polynomial. The experimental implementation of this evaluation, however, involves many known experimental challenges. Here we present experimental results for a small-scale approximate evaluation of the Jones polynomial by nuclear magnetic resonance (NMR); in addition, we show how to escape from the limitations of NMR approaches that employ pseudopure states. Specifically, we use two spin-1/2 nuclei of natural abundance chloroform and apply a sequence of unitary transforms representing the trefoil knot, the figure-eight knot, and the Borromean rings. After measuring the nuclear spin state of the molecule in each case, we are able to estimate the value of the Jones polynomial for each of the knots.

OSTI ID:
21413291
Journal Information:
Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 81; ISSN 1050-2947; ISSN PLRAAN
Country of Publication:
United States
Language:
English