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Study Shows Factors on Quantum Computation Speed Limit

Gal Ness and Professor Yoav Sagi of Technion

Technion team members Gal Ness (left) and Professor Yoav Sagi (right).

Credit: Rami Shlush / Technion

Which factors determine how fast a quantum computer can perform its calculations? Physicists at the University of Bonn and the Technion – Israel Institute of Technology have devised an experiment to answer this question. The results are described in "Observing Crossover Between Quantum Speed Limits," published in the journal Science Advances.

Quantum computers rely on the principles of quantum mechanics to process information, but fundamental limits apply to the amount of data they can process in a given time."Even in the quantum world, gates do not work infinitely fast," says co-author Andrea Alberti at the University of Bonn. "They require a minimum amount of time to transform the wave function and the information this contains."

The researchers demonstrated that the minimum time for a matter wave to change depends on energy uncertainty. "The greater the uncertainty, the shorter the Mandelstam-Tamm time," says Professor Yoav Sagi at Technion, referring to a 70-year-old theoretical deduction of the minimum time for transforming the wave function.

The physicists also proved a second speed limit, which was theoretically discovered about 20 years ago. The ultimate speed limit in the quantum world is therefore determined not only by the energy uncertainty, but also by the mean energy.

"It is the first time that both quantum speed boundaries could be measured for a complex quantum system, and even in a single experiment," Alberti says.

From American Technion Society
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