An ensemble of nuclear spin-pairs under certain conditions is known to exhibit singlet state life-times much longer than other non-equilibrium states. This property of singlet state can be exploited in quantum information processing for efficient initialization of quantum registers. Here we describe a general method of initialization and experimentally demonstrate it with two-, three-, and four-qubit nuclear spin registers.
Cite
@article{arxiv.1008.1876,
title = {Initialization of NMR Quantum Registers using Long-Lived Singlet States},
author = {Soumya Singha Roy and T. S. Mahesh},
journal= {arXiv preprint arXiv:1008.1876},
year = {2010}
}