Researchers devise a new path toward ‘quantum light’

Researchers have theorized a new mechanism for producing high-energy ‘quantum light’. It can be used to investigate new properties of matter at the atomic scale.

Researchers at the University of Cambridge, together with colleagues in the United States, Israel and Austria, have developed a theory that explains a new state of light with controllable quantum properties over a wide range of frequencies up to X-ray frequencies. The results have been reported in the journal natural physics.

The world we see around us can be described according to the laws of classical physics, but when we observe things at the atomic scale, quantum physics snatch. Imagine basketball: naked eye, basketball behaves according to the laws of classical physics. But the atoms that make up the basketball behave according to quantum physics instead.

“Light is no exception. radio wavesLead author Dr Andrea Pizzi, who was based at the Cavendish Laboratory in Cambridge, said: I can’t explain them. ”

Pizzi, now based at Harvard University, collaborated with Ido Kaminer’s group at the Technion-Israel Institute of Technology and colleagues at MIT and the University of Vienna to develop a theory that predicts new ways to control the quantum properties of light.

“Quantum fluctuations make the study of quantum light more difficult, but they also make it more interesting. If designed correctly, quantum fluctuations can be a resource,” said Pizzi. “Controlling the state of quantum light may enable new techniques in microscopy and quantum computing.”

One of the main techniques for producing light uses powerful lasers. When a sufficiently powerful laser is aimed at a collection of emitters, it can draw electrons away from them and energize them. Eventually some of these electrons recombine with the emitter from which they were extracted, surplus energy They are absorbed and emitted as light. This process transforms low frequency input light into high frequency output radiation.

“The assumption was that these emitters were all independent of each other, resulting in an output light that was almost featureless in quantum fluctuations,” said Pizzi. “We wanted to study systems in which the emitters are correlated rather than independent. The state of one particle can tell us something about the state of another. In this case, the output light is very , and its quantum fluctuations are highly structured, potentially more useful.”

To solve this type of problem, known as the many-body problem, researchers use theoretical analysis and computer simulationwhere the output light from a group of correlated emitters can be described using the quantum Physics.

Led by Technion’s Pizzi and Alexey Gorlach, the theory shows that controllable quantum light can be generated by correlated emitters using powerful lasers. This method produces high-energy output light and can be used to design X-ray quantum optical structures.

“I spent months working to make the equations clearer until I was able to describe the relationship between the output light and the input correlation with just one compact equation. As a physicist, I find this beautiful. Pizzi.

“Going forward, we hope to work with experimentalists to provide validation of our predictions. On the theoretical side, our work suggests: many body Beyond the setup considered in this work, as a resource for generating quantum light, it is a concept that we would like to explore more broadly. ”