The relationship between ensemble quantum computing logical gates and NMR pulse sequence engineering exemplified by the SWAP operation

Abstract

This paper describes how to derive nuclear magnetic resonance (NMR) pulse sequences suitable as ensemble quantum computing logical gates by known systematic tools for design of pulse sequences in NMR spectroscopy. This is in contrast to the current trend of developing NMR pulse sequences for ensemble quantum computing independent of established NMR spectroscopic technology, although many of the pertinent spin manipulations are already known in NMR spectroscopy. The SWAP operation is discussed in detail and one version is only (2J)−1long, which compares favorably with 3(2J)−1 in a recent implementation (Linden N, Barjat H, Kupce E, Freeman R. Chem Phys Lett 1999; 307:198–204). Alternatively, the number of π pulses can be reduced in that sequence. © 2000 John Wiley & Sons, Inc. Concepts Magn Reson 12: 389–395, 2000