A 150-year-old thought experiment prompted a group of Canadian scientists from Simon Fraser University (SFU) to develop a remarkably fast engine that operates on a unique fuel — Information.
The engine, which was revealed in the Proceedings of the National Academy of Sciences, turns the random jiggling of small particles into stored energy and has the potential to dramatically improve the speed and efficiency of computers and bio-nanotechnology.
What exactly is an information-powered engine?
We are accustomed to thinking of engines as devices that use gasoline and assist us in driving our vehicles, so an information-fueled engine may not strike any bells. This concept is a descendent of a thought experiment conducted 150 years ago by the famous physicist James Clerk Maxwell. Maxwell wondered what would happen if he could examine a small and exact system and track its microscopic alterations as it moved due to the air or water molecules around it. Could we exploit and control that motion to turn Information into ‘work’?
“That’s the type of data we’re looking for,” said SFU physics professor and senior author Prof. John Bechoefer in a video posted on the university’s website. “We wanted to see how quickly an information engine could go and how much energy it could extract, so we built one.”
It has the ability to create power that is “comparable to molecular machinery in living cells.”
Their information engine is a small particle ‘bead’ submerged in water. It’s linked to a spring, which is coupled to a moveable stage. According to a university news release, because a particle is too small to be tied to a spring, the researchers used an optical trap, which utilizes a laser to put a force on the particle that mimics the spring and stage.
Thermal motion causes the particle to bounce up and down, which the researchers observed while serving as Maxwell’s demon. In Maxwell’s thought experiment, a demon would open a door between two gas chambers, guiding fast-moving gas molecules into one and slower ones into the other. When the researchers detected an upward bounce in their study, they pushed the stage up in response, and they waited for a downward bounce.
By repeating this motion, they lifted the particle without physically pulling on it, so storing a considerable quantity of gravitational energy. “This ends uplifting the entire system using only information about the particle’s position,” says Ph.D. student Tushar Saha, who participated in the work.
The researchers also discovered an intriguing trade-off between particle mass and the average time it takes for a particle to bounce up. “While larger particles may store more gravitational energy, they also take longer to travel up,” Master of Science student Joseph Lucero explained.
The researchers were able to get the system to produce enough power that is “similar to molecular machinery in living cells,” with “speeds comparable to fast-swimming bacteria,” and the obtained power and speed outranked previously reported engines by at least an order of magnitude, according to postdoctoral fellow Jannik Ehrich.
From a thought experiment conceived 150 years ago to real implementation, it will be fascinating to watch what kind of applications arise from information-fueled engines in the future, particularly in computers and bio-nanotechnology.