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Not that it will add to the charging capacity of electric cars. But the concept of the quantum battery presented earlier this month can justifiably be called a breakthrough. The principle behind it is the superposition of two energy levels. It has been shown that recharging time is inversely proportional to the amount of energy stored. In other words, the greater the amount of energy, the faster the charging time. This is very useful in wireless charging, among other things.

The international study, which was published in ScienceAdvances, involved scientists from the University of Sheffield, the University of St Andrews (United Kingdom), the University of Adelaide (Australia) and Heriot-Watt University (Scotland). On the Italian side, the Institute of Photonics and Nanotechnology (part of the National Science Council) and the Polytechnic University of Milan were among those involved. Innovation Origins spoke with Giulio Cerullo (56), Professor of Physics at this Milan University.

Giulio Cerullo © Polimi

What is a quantum battery?

“This is a fairly new concept to the general public. The quantum battery constitutes a new form of energy storage that works according to the principles of quantum physics. That is the science that studies the infinitely small and where the laws of classical physics do not always apply. Central to this is the idea that molecules absorb light as speed accelerates.”

What was the nature of the experiment?

“We have built a test setup in the joint laboratory of the Institute of Photonics and Nanotechnology and the Polytechnic University in Milan. The device is made up of a ‘microcavity‘ consisting of thin layers of light-absorbing organic molecules a few nanometers in size. Each molecule represents a unit that can exist in a state of quantum superposition of two energy levels.”

Superposition, as we know it from quantum computing?

“In a sense, yes. The qubit, the basic unit of quantum information, can be zero and one at the same time. The quantum battery works because each molecule is capable of existing in a superposition of two energy levels.”

What conclusions did it draw?

“That with the quantum battery, at least in the test setup, charging power will accelerate by increasing the battery capacity. By building a quantum battery in the future so that entities can exist in superposition, the overall system can behave as a collective. This behavior, known as quantum coherence, allows the entities to work together, creating an ultra-fast charging rate that is dependent on the number of individual molecules.”

Is this a unique concept?

“To the best of my knowledge, this has not been done before.”

What’s going to happen now?

“We are continuing on the path that we have started out on. There are already investors in the field of deep tech who are interested. Our work offers the prospect of exploiting collective effects in the coupling of light and matter for energy storage.”

When will we be able to charge at lightning speed and wirelessly?

“I think in about ten years’ time.”

Also read how quantum dots help photonics advance and what the quantum computer can mean for the automotive industry.