Initialization of NMR Quantum Registers using Long-Lived Singlet States

Abstract: 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.