Mission (im)possible: controlling light while measuring trapped ion qubits

Waterloo researchers achieve breakthrough in protecting qubits during quantum measurements.

By Samantha Clark

Quantum information is fragile and often difficult to protect during experiments. Protecting qubits from accidental measurements is essential for controlled quantum operations, especially during state-destroying measurements or resets on adjacent qubits in protocols like quantum error correction. Current methods to preserve atomic qubits against disturbances can waste coherence time, extra qubits, and introduce errors.

Researchers have successfully demonstrated the ability to measure and reset a trapped ion qubit to a known state without disturbing neighbouring qubits just a few micrometres away — a distance smaller than the width of a human hair, which is about 100 micrometres thick.

The demonstration has the potential to impact future research in the field in major ways, including advancing quantum processors, enhancing speed and capabilities for tasks like quantum simulations in machines that already exist today, and in implementing error correction.

This breakthrough was achieved by a team led by Rajibul Islam, a faculty member at the Institute for Quantum Computing (IQC) and professor in the Department of Physics and Astronomy at the University of Waterloo, along with postdoctoral fellow Sainath Motlakunta and students in their research group.