Mini-engine exploits noise to convert information into fuel
Background noise in any work environment is usually guaranteed to disrupt work.
But physicists have developed a micro-scale engine that runs in the presence of noise
Engines and motors are everyday things we encounter in our lives. We use them to power machines to make work.
Things are more complicated in the microscopic world, where heat is noisier than it is on Earth, and can easily scramble things up.
"Heat makes the components of small machines jiggle back and forth all the time," explains John Bechhoefer, a quantum physicist at Simon Fraser University
Reducing the amount of useful work a tiny engine can produce is usually the result of thermal noise from heat.
Information engines are small machines that can exploit noise to move in a directed way.
An information engine acts by measuring small movements caused by heat and using that information to reinforce the movements
Physicists and engineers are excited about building such tiny information-harnessing motors to design novel tiny machines.
John Bechhoefer says that an information engine converts information into work. A group of people have built an information engine using a glass bead suspended in water
The bead is held in place by a beam of light that acts as a support. Every bead will be buffeted up, due to natural thermal fluctuations in the liquid, as the molecules in the water
The team raises the laser support when they measure the bead's movement against gravity due to thermal fluctuations.
The bead has more stored energy, like a ball that is ready to be dropped, in this higher position.
The team didn't have to work to lift the particle up, it happened naturally thanks to the jiggles of the water molecules
The laser trap is adjusted using feedback about the bead's motion to convert the thermal heat from the water into stored energy.
If too much measurement noise is generated from the laser beam used to locate the bead, it is difficult to implement the strategy
In such cases, the uncertainty in the bead's position can be greater than the bead's movements produced by water