Information as Fuel
A group of scientists from Simon Fraser University (SFU) in Canada were inspired by a 150-year-old thought experiment to construct a remarkably fast engine that runs on a unique fuel — information as fuel.
The engine, which was detailed in a report published in the Proceedings of the National Academy of Sciences, converts the random jiggling of microscopic particles into stored energy and has the potential to boost the speed and affordability of computers and bio-nano technology dramatically.
Information as Fuel of Engine
We’re used to thinking of engines as fuel-guzzling machines that let us drive our cars, so an information-fueled engine may come as a surprise. This concept is a descendant of a thought experiment conducted 150 years ago by renowned physicist James Clerk Maxwell.
What would happen if you could view a system so small and so precisely that you could observe its minute changes as it moved owing to the air or water molecules around it? Maxwell asked. Could we take that motion and harness it in a way that allows us to convert data into ‘work’?
In an SFU video, physics professor and senior author Prof. John Bechoefer noted, “That’s the kind of information we’re using. We built one to see how fast an information engine could go and how much energy it could extract.”
Their information as fuel engine is a small particle ‘bead’ immersed in water. It’s attached to a spring that moves with a moving stage. The researchers used an optical trap, which utilises a laser to create a force on the particle that imitates the spring and stage, because a particle is too small to be hooked to a spring, according to a press statement from the university.
The particle bounces up and down due to thermal motion, which the researchers detect, acting as Maxwell’s demon. A demon would operate a door between two gas chambers in Maxwell’s thought experiment, with the purpose of directing fast-moving gas particles into one compartment and slow-moving gas particles into the other. When the researchers witnessed an upward bounce in their experiment, they lifted the stage up in response, and they waited for a downward bounce.
Accumulate Gravitational Energy
By repeating this procedure, they were able to lift the particle without having to directly tug on it, accumulating a considerable quantity of gravitational energy. “This ends up raising the entire system using simply knowledge about the particle’s position,” says Tushar Saha, a Ph.D. student who participated in the study.
The scientists also uncovered an intriguing trade-off between particle mass and the average time it takes for a particle to bounce up. “Heavier particles can store more gravitational energy, but they take longer to travel up,” explained Master of Science student Joseph Lucero.
Outperform with Information as Fuel
According to postdoctoral fellow Jannik Ehrich, the researchers were able to get the system to generate enough power that it is “comparable to molecular machinery in living cells,” with “speeds comparable to fast-swimming bacteria,” and the extracted power and velocity outperform previously reported engines by at least an order of magnitude.
It will be fascinating to observe the kind of applications that may emerge from information-fueled engines in the future, notably in computers and bio-nano technologies, as a result of a thought experiment conceived 150 years ago.