Quantum batteries could recharge faster by disrupting the rules of cause and effect

Research shows that future quantum batteries can obtain electricity by breaking the traditional laws of cause and effect.

Traditional batteries are charged by converting electrical energy into chemical energy through a large number of electrons.

But in a new proof-of-principle experiment, researchers show how a strange quantum effect can make batteries charge faster and more efficiently by disrupting cause-and-effect relationships, according to research published Dec. 14 in the journal efficiency. Physical Review Letters.

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Causation, or cause and effect, is not always direct Quantum mechanicsthe strange rules that govern the tiny world.

“Normally, if event A happens first and causes event B, it is assumed that B cannot also cause A,” said co-first author Chen Yuanboa physicist from the University of Tokyo told LiveScience. “However, recent advances in theoretical physics suggest that in certain frameworks the scenarios ‘A causes B’ and ‘B causes A’ may simultaneously hold.”

The principle of quantum superposition enables particles to exist in many different states simultaneously, at least until they are observed and “choose” a state to fall into.

Any property of a quantum object (such as its momentum, position, or, in the famous example) Erwin Schrödinger’s imaginary cat, Whether it is alive or not) can exist in a superposition, a probabilistic chaos consisting of every possible state that only collapses into a deterministic outcome when the object is observed.

This realization led physicists to conduct all kinds of strange experiments Contradicts our intuitive notions of what is possibleincluding situations where a single particle can be present and absent in many different places simultaneously.

But superposition messes not only with our intuition about space, but also with our sense of cause and effect. In 2009, physicist A device called a quantum switch is used to observe a phenomenon called indeterminate causal order. By sending light particles, or photons, along a pair of different paths, physicists split themselves into two possible versions, one along the first path and the other along the second path.

Then, depending on the path the photon takes, physicists apply two different processes in different orders depending on the path. The result is a photon with chaotic causality: it is in a quantum superposition in which both events are in the correct order.

“Suppose we have two processes: A and B,” Chen said. “Using quantum switches, you can create a superposition of (apply A first, then B) and (apply B first, then A).”

Chen and his colleagues wondered whether they could integrate it into a quantum battery, a device that could theoretically store photon energy and charge it faster than traditional electrochemical cells.

They compared three charging methods: connecting the two chargers to the battery sequentially, simultaneously, or on top of each other so the order of inputs cannot be distinguished.

Their calculations showed that the superposition approach would allow a low-power, causally disrupted charger to deliver more energy more efficiently than a traditional high-power charger.

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They followed up their calculations with proof-of-principle experiments using light. By sending photons through a quantum switch with two possible paths, the researchers split the light particle into two possible versions, each taking a different path.

Then, after placing the light into two inputs, polarizing them in a different order (A then B or B then A) depending on the path they were on, the researchers measured the final polarization and found that the individual photons had been causally upset.

After testing their protocol, the scientists say their next challenge is to create a physical quantum battery that can be recharged. However, the first experimental evidence of quantum batteries was only published last year, so it probably won’t happen anytime soon.

“Given the current limited experimental work and ongoing theoretical exploration in the quantum battery field, estimating a precise timeline for achieving conclusive results is challenging,” Chen said.