A novel process for producing high-energy “quantum light” has been suggested; this light might be used to look at novel atomic-scale aspects of matter. The researchers from the University of Cambridge created a theory defining a novel form of light with adjustable quantum features over a wide frequency range, up to X-ray frequencies, in collaboration with colleagues from the United States, Israel, and Austria.
The physical principles that govern the world we see around us can be applied to it, but when we see something at an atomic level, the weird world of quantum physics takes control. If you observe a basketball with your naked eye, you will notice that it behaves in accordance with the rules of classical physics. But the basketball’s constituent atoms operate in a way that is consistent with quantum physics.
According to lead author Dr. Andrea Pizzi, who conducted the research while employed at Cambridge’s Cavendish Laboratory, “light is no exception: from sunlight to radio waves, everything can mostly be described using classical physics.” However, at the micro- and nanoscale,’so-called quantum fluctuations’ start to matter, and classical physics is unable to explain them. In order to create a theory that predicts a new method of controlling the quantum nature of light, Pizzi collaborated with Ido Kaminer’s team at the Technion-Israel Institute of Technology, as well as with colleagues at MIT and the University of Vienna. Pizzi is currently based at Harvard University.
Quantum fluctuations make quantum light more challenging to understand but also more fascinating since, with the right engineering, they may be used as a resource. New methods for microscopy and quantum computation may be made possible by controlling the state of quantum light.
Strong lasers are used in one of the primary methods for producing light. When a powerful enough laser is directed towards a group of emitters, it has the ability to liberate some of the emitters’ electrons, energizing them. The extra energy that these electrons acquired is eventually released as light when some of them reunite with the emitters from which they were originally removed. The low-frequency input light is converted into a high-frequency output radiation by this mechanism.
According to Pizzi, “the assumption has been that all these emitters are independent from one another, resulting in output light with pretty featureless quantum fluctuations.” “We wanted to investigate a system in which the emitters are not independent but rather correlated, meaning that you can infer something about the state of one particle from the state of another. The output light in this scenario begins to behave considerably differently, and its quantum fluctuations take on a highly organized appearance that makes them potentially more valuable.”
The output light from a collection of correlated emitters might be explained using quantum physics, thus the researchers used theoretical analysis and computer simulations to address this type of challenge, also known as a many body problem. The theory, whose research was spearheaded by Pizzi and Alexey Gorlach from the Technion, shows that correlated emitters with a potent laser can produce programmable quantum light. The technique produces high-energy output light and might be used to modify the X-rays’ quantum-optical structure.
“We spent months refining the equations, until we were able to express the relationship between the input correlations and the output light in a single, concise equation. This is lovely to me as a physicist, “Spizzi stated. “In order to validate our forecasts in the future, we would like to work with experimentalists. On the theoretical front, our finding indicates many-body systems as a source for producing quantum light, a notion that we want to explore more thoroughly, outside of the particular setting taken into account in our work.”