Qubit addressing using hyperfine-interaction control by an electric field in a magnetic crystal

Abstract

We demonstrate experimentally the hyperfine-interaction control by an electric field, which is the operating principle of the addressable qubit operation in a silicon-based solid-state quantum computer in a new quantum computer system, a magnetic crystal. The transferred hyperfine field at a ${\mathrm{F}}^{\ensuremath{-}}$ nucleus caused by neighboring ${\mathrm{Mn}}^{2+}$ electron spins in an antiferromagnetic ${\mathrm{MnF}}_{2}$ single crystal was measured by $^{19}\mathrm{F}$ nuclear magnetic resonance (NMR) with an external electric field applied along the [110] crystal direction. The electric field splits the $^{19}\mathrm{F}$ NMR peak into two resolved lines that come from the F nuclei located at geometrically equivalent sites. A line splitting of 56 kHz was achieved at an electric field of 3.4 V/$\ensuremath{\mu}$m. One of the ${\mathrm{F}}^{\ensuremath{-}}$ nuclear spins could be flipped selectively by a composite radio-frequency pulse while leaving the other unchanged, thereby demonstrating qubit addressing via electric field control of the hyperfine interaction.