Two European theoretical physicists have shown that it may be possible to build a near-perfect, entangled quantum battery. In the future, such quantum batteries might power the tiniest of devices — or provide power storage that is much more efficient than state-of-the-art lithium-ion battery packs.

To understand the concept of quantum batteries, we need to start (unsurprisingly) at a very low level. Today, most devices and machines that you interact with are governed by the rules of classical mechanics (Newton’s laws, friction, and so on). Classical mechanics are very accurate for larger systems, but they fall apart as we begin to analyze microscopic (atomic and sub-atomic) systems — which led to a new set of laws and theories that describe quantum mechanics.

In recent years, as our ability to observe and manipulate quantum systems has grown — thanks to machines such as the Large Hadron Collider and scanning tunneling electron microscopes — physicists have started theorizing about devices and machines that use quantum mechanics, rather than classical. In theory, these devices could be much smaller, more efficient, or simply act in rather unsurprising ways. In this case, Robert Alicki of the University of Gdansk in Poland, and Mark Fannes of the University of Leuven in Belgium, have defined a battery that stores and releases energy using quantum mechanics.

A quantum system (say, the single proton and electron in a hydrogen atom) has a quantum state, defined by the electron’s movements. (Quick aside: In our previous discussions of spintronics and quantum computing, it is thespin of the electron (clockwise, counterclockwise, etc.) that is converted into a qubit value). Some quantum states have a very small amount of energy that can be extracted, returning it to a passive, neutral state. In theory, according to Alicki and Fannes, it should be possible to build a quantum battery that is full of energy-rich quantum states — and then, somehow, recharge it when you run out of juice.

As the Physics Arxiv Blog notes, such perfect energy transfer readily occurs in nature, such as during photosynthesis — but no one knows why. It’s just one possible explanation, of course, but maybe Gaea has a bit of a head start on quantum batteries.

Research paper: arXiv:1211.1209 “Extractable work from ensembles of quantum batteries. Entanglement helps.”