Quantum engine could power devices with an ultracold atom cloud

quantum engine that works by toggling the properties of an ultracold atom cloud could one day be used to charge quantum batteries.

It’s possible to build a quantum engine that is powered by a constant shifting in the fundamental quantum nature of the particles it contains. Such devices could one day be used to power other quantum technologies.

All known particles can be categorised as either fermions or bosons, and which category they fall into determines how they behave in large groups. Artur Widera at the University of Kaiserslautern-Landau in Germany and his colleagues worked out how to make an engine with a collection of atoms by forcing them to behave first like bosons, then fermions, then bosons again.

The difference between these two types of particles is most prominent in the quantum realm, particularly at extremely low temperatures. So the researchers built their engine from a few hundred thousand lithium atoms cooled to a temperature within a fraction of a degree of absolute zero.

Under these conditions, they used carefully-tuned magnetic fields to make the lithium atoms behave either like a group of fermions or, after they forced them to form molecule-like pairs, a group of bosons.

The researchers started with a collection of boson-like paired-up atoms. First they compressed them, then converted them into a collection of fermions, which increased their collective energy.