Thinking outside the box, researchers at the University of Tokyo reveal an energising potential that efficiently harnesses quantum battery power.
Nowadays, the word quantum appears more often, even in hyperboles, such as quantum leaps. Indeed, quantum technology is attempting to make dramatic strides, particularly in battery development.
The race to produce this type of charging device boasting fantastic efficiency may intensify, with a caveat: As with many technologies, inherent limiting factors exist. Time is one such hurdle through which our current thermodynamic paradigm must leap.
However, a research group at the University of Tokyo (UTokyo) inspired a maverick move against conventional wisdom with their indefinite causal order, or ICO, that allows quantum particles such as electrons to behave in such a way that enables low-power devices to charge exceedingly better than conventional batteries.
“I’m particularly interested in the way quantum particles can work to violate one of our most fundamental experiences, that of time,” says Yuanbo Chen of UTokyo’s Department of Information and Communication Engineering.
Let us rewind a little before leaping ahead.
Chemical batteries abide by Newtonian laws of physics and rely on charging in a known pathway, in which time governs the system. In conventional charging, we observe subatomic particles transitioning from one stage to the next, but we cannot pinpoint where they might be at any particular moment. In other words, the schematics follow the traditional concept of causality, whereby you can’t eat cake and have it, too.
In contrast, the microscopic particles in quantum batteries are, by nature, delocalised; there is no way to know which direction or path they will take. Taking advantage of that fact, Chen’s group applied ICO to create a quantum superposition in which both directions of causality can exist simultaneously.
The ICO system’s energy storage and thermal efficiency showed significant gains. But the other half of the story, as explained in the American Physical Society on 25 October 2023, proposed there was more bang for the buck.
“A lower-power quantum protocol could outperform conventional or higher-power ones using the same apparatus operating under coherently controlled processes,” posits Chen.
Senior colleague and co-author Yoshihiko Hasegawa from the same department, echoes Chen’s aspirations for their ICO’s future.
“Our promising result with the quantum battery hints at the potential impact on solar panel efficiency and may open windows of opportunity for other thermodynamic applications moving forward.”
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The paper “Charging Quantum Batteries via Indefinite Causal Order: Theory and Experiment” appeared in Physical Review Letters on 13 December 2023, with doi:10.1103/PhysRevLett.131.240401.