Using laser light, researchers have developed the most robust method currently known to control individual qubits made of the chemical element barium. The ability to reliably control a qubit is an important achievement for realizing future functional quantum computers.
This new method, developed at the University of Waterloo’s Institute for Quantum Computing (IQC), uses a small glass waveguide to separate laser beams and focus them four microns apart, about four-hundredths of the width of a single human hair. The precision and extent to which each focused laser beam on its target qubit can be controlled in parallel is unmatched by previous research.
“Our design limits the amount of crosstalk–the amount of light falling on neighbouring ions–to the very small relative intensity of 0.01 per cent, which is among the best in the quantum community,” said Dr. K. Rajibul Islam, a professor at IQC and Waterloo’s Department of Physics and Astronomy. “Unlike previous methods to create agile controls over individual ions, the fibre-based modulators do not affect each other.
“This means we can talk to any ion without affecting its neighbours while also retaining the capability to control each individual ion to the maximum possible extent. This is the most flexible ion qubit control system with this high precision that we know of anywhere, in both academia and industry.”
Read more at the University of Waterloo
Image Credit: University of Waterloo