How Do We Make Transforming Quantum Circuits? Lasers and Ultracold Atoms

By Sarah Zhang on at

Well, here's a cooooool finding. Take any piece of electronic equipment you can think of and its circuits are powered by, yes, electrons. But a new experiment takes us one step closer to "atomtronic circuits" made of super-cold quantum matter that can be reconfigured on the fly.

Scientists at Los Alamos National Laboratory started with clouds of atoms very close to absolute zero, a state of matter called the Bose–Einstein condensate. These atom clouds have a special property where they act as a quantum object. To make the circuits, the team just needed lasers, which New Scientist explains:

Their circuits are built from two laser beams, one that creates a horizontal sheet of light to act as a circuit board, and another vertical laser that traces out the path of the circuit. The condensate, which is made from around 4000 cooled rubidium atoms, is trapped inside the beams by the same forces used to create optical tweezers, which can manipulate particles on a small scale.

Unlike your ordinary electric circuit, which is made of tangible matter, this quantum circuit is just made of light. That means we could redraw the circuit while it's in use, allowing complex circuits to be packed into a smaller space, the researchers tell New Scientist.

A similar system of condensates on lasers is already being studied to create a quantum navigational system for submarines, which can't rely on GPS deep underwater. Someday, it could come in handy on land as well. [New Scientist, ArXiv]

Top image, left: Intersecting laser beams (pink) outline a Y-shaped path for the Bose-Einstein condensate. Right: Straight, bending, Y-shaped, and square circuit paths created by lasers. Credit: Ryu etal.