Over the past decades, astounding advances have been made in the laser technologies and the understanding of light-matter interactions. Thanks to this, scientists have been able to carry out complex experiments related, for example, to ultra-fast light-pulses in the visible and infrared range, and accomplish crucial milestones such as using a molecule’s own electrons to image its structure, to see how it rearranges and vibrates or breaks apart during a chemical reaction.
The development of high-power lasers allowed scientists to study the physics of ultra-intense laser–matter interactions which almost always treats ultra-strong ultra-short driving laser pulses only from a classical point of view. The famous theory coined as the “three-step model”, which had its 25th anniversary in 2019, dealt with the interaction of an electron with its parent nucleus in a strong laser field, and elegantly described it according to classical and quantum processes. However, since the laser pulses are highly coherent and contain huge numbers of photons, this description so far has been incomplete, treating the atomic system in a quantum way but the EM field classically.
So far, in the description of the most relevant processes of ultra-intense laser–matter physics, the quantum-fluctuation effects of the laser electric field, not even to mention the magnetic fields, were negligible. However, the quantum nature of the entire EM fields is always present in these processes, so a natural question arises: does this quantum nature exhibit itself?
In the recent study published in Nature Physics, ICFO researchers, led by ICREA Prof. Maciej Lewenstein and Javier Rivera, with colleagues from Technion-China, Max Born Institute in Berlin, the experimental group of Paraskevas Tzallas, from FORTH, have reported on the demonstration that intense laser–atom interactions may lead to the generation of highly non-classical states of light, the so called photonic Schrödinger cat states. This work opens the path toward fascinating applications in quantum information and quantum technologies.
