Extremely cold atoms tunnelling through a crystal made of light could create a stable quantum battery. This could solve a long-standing issue with quantum batteries 鈥� it would stop them leaking energy after they charge 鈥� and could help them offer an advantage over conventional batteries.
Quantum batteries extract energy from quantum processes, such as those involved in moving particles. Very few have been built and there is no consensus on a best design for them. at the University of Barcelona in Spain and his colleagues propose to use atoms almost as cold as absolute zero and a special configuration of laser beams.
Ultracold atoms are both very susceptible to quantum effects and can be very precisely controlled by the electromagnetic forces of laser light. That means we can use lasers to arrange them into neat lattices that resemble the arrangement of atoms in natural crystals. Juli谩-D铆az and his team studied a mathematical model where lasers are oriented so that there are only three positions available to the atoms, each corresponding to a higher energy than the previous. These are analogous to three holes on a golf course going up a hill where a ball in the highest one would have the highest gravitational potential energy.
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For the atoms, the three potential energy wells constitute the battery, and for it to be fully charged, all atoms have to be in the highest well. While balls in holes typically must remain stuck, because of the ultracold atoms鈥� quantum properties, they can tunnel from one well to the next.
However, researchers can control how many atoms tunnel between any two wells by applying pulses of electromagnetic radiation. The team devised a sequence of such pulses that would make all the atoms end up in the most energetic well but not allow them to tunnel back down the energy ladder, as the quantum states they would have to assume to do so would be prohibited by the electromagnetic forces. Their calculations show a stable way to charge the quantum battery 鈥� and keep it charged.
鈥淪tability is the key point here,鈥� says at University College Dublin in Ireland. He says this stability is possible to achieve in experiments today. 鈥淭he work really takes a candidate setting for a quantum battery and brings it closer to a meaningful realisation,鈥� says Campbell.
Juli谩-D铆az says there are still many details left for his team to work out, such as how exactly the battery would connect to other devices. Eventually, this design could become part of some larger 鈥渁tomtronics鈥� device where ultracold atoms may be used for sensing or computation, and they would be powered by some of them acting like a battery, he says.
Journal reference:
Physical Review A,
