Mastering the behavior of light at the quantum scale could greatly advance quantum computing. This experience adds a new brick in the understanding of phenomena at an infinitesimal threshold.
” This paves the way for the manipulation of what is called ‘quantum light’ “says Sahand Mahmoodian. With his international team of physicists, a small number of photons grouped together could be identified and manipulated. This is an important first, although on a very small scale in the immediate future. The results were published in Nature on March 20, 2023.
It is important to distinguish between the quantum entanglement of atoms, now well mastered by physicists, and this same operation for light, via photons, which is very difficult to control in the laboratory. This is why Syndey University, of which Sahanh Mahmoodian is a member, considers this an unprecedented achievement which ” is an important step in the development of quantum technologies. »
” It’s very promising »
The experiment is based on a phenomenon called “stimulated emission”. Physicists fired a photon and a pair of photons at a quantum dot (or box) — a nanostructure that acts as an artificial atom. “ The device we built induces such strong interactions between photons that we could observe the difference between one photon and two photons interacting with it “, explains Natasha Tomm, co-author of the study with Sahand Mahmoodian.
Thus, in the diffusion delay at the heart of this interaction, a single photon was delayed more than two photons linked together. A counter-intuitive situation, as is often the case in the quantum field, but which makes it possible to better understand, and therefore better control, this phenomenon.
” With this very strong photon-photon interaction, the two photons become entangled in the form of what is called a ‘bound state’ of two photons “, details Natasha Tomm. It is precisely by artificially stimulating this bound state that the experiment has accomplished its objective – namely ” an essential first step towards harnessing quantum light for practical purposes according to these physicists.
Next step: find a way to harness this mastery of quantum light to generate states of light that can be used in quantum computing — and thus help stabilize these new systems. Natasha Tomm believes that ” it holds great promise for applications in a wide range of fields: from biology to advanced manufacturing and quantum information processing. »
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