The study of non-perturbative interactions between light and matter has long intrigued researchers, as these interactions cannot be adequately described using perturbation theory. Quantum properties of light, however, have not been extensively explored in relation to these interactions and the phenomena that arise from them. Recently, a team of researchers from Technion–Israel Institute of Technology introduced a groundbreaking theory that sheds light on this unexplored territory. Their work, published in Nature Physics, not only has the potential to guide future experiments in strong-field physics phenomena but also to advance the development of quantum technology.
The Journey Towards the Theory
The development of this theory was a collaborative effort between three research groups at Technion, led by Prof. Ido Kaminer, Prof. Oren Cohen, and Prof. Michael Krueger. Spearheaded by students Alexey Gorlach and Matan Even Tsur, the study aimed to address the inconsistency between different theories that explained fundamental phenomena in physics. The researchers focused on high harmonic generation (HHG), a highly nonlinear process that involves the emission of high-harmonics of intense light pulses when applied to matter.
Prof. Kaminer and his research group had been working on a unified quantum theory-based framework that could encompass all photonics phenomena, including HHG. Their previous paper, published in Nature Communications in 2020, presented an initial version of this framework, analyzing HHG within the context of quantum optics. However, at that time, HHG experiments were still driven by classical laser fields. The team became intrigued by the possibility of using intense quantum light, specifically bright squeezed vacuum, to induce HHG.
Quantum Light’s Impact on Strong-Field Physics
The recent study by Prof. Kaminer, Gorlach, and their colleagues culminated in a comprehensive framework that describes strong-field physics processes driven by quantum light. The researchers applied this framework to HHG, revealing unexpected changes in intensity and spectrum when using different quantum photon statistics. Their paper not only predicts experimentally feasible scenarios but also emphasizes the influence of photon statistics on these phenomena. Future experiments in strong-field quantum optics will undoubtedly benefit from these groundbreaking findings.
While the presented theory is currently purely theoretical, it lays the foundation for unprecedented research in non-perturbative processes driven by quantum light. The team’s approach involves splitting the driving light into two representations, the generalized Glauber distribution and the Husimi distribution, and separately simulating their effects on the overall result using the time-dependent Schrodinger equation (TDSE). This novel approach enables the study of arbitrary quantum light states and systems of emitters.
Expanding Beyond High Harmonic Generation
The potential applications of the developed theory extend far beyond HHG. The research team envisions its utilization in a wide range of non-perturbative processes, all of which can be driven by non-classical light sources. In a related theory paper published in Nature Photonics, the researchers propose controlling attosecond pulse profiles using the quantum nature of light. This advancement could significantly contribute to quantum sensing and quantum imaging technologies. Additionally, the theory could be applied to other strong-field physics phenomena, such as the Compton effect, for generating X-ray pulses.
Future Experimental Validation and Generalization
The research team is eager to test their theory in experimental settings. For example, their framework can be applied to the generation of attosecond pulses through HHG. These pulses play a crucial role in quantum sensing and imaging technologies, making the validation of the theory even more significant. Furthermore, the researchers aim to apply their theory to explore quantum effects in various materials driven by intense light, bridging the gap between quantum optics and condensed matter physics.
The introduction of a new theory describing non-perturbative interactions driven by quantum light marks a significant milestone in the field of strong-field physics. With the potential to revolutionize future experiments and advancements in quantum technology, this theory opens doors to a vast realm of unexplored phenomena. As researchers push the boundaries of scientific knowledge, the integration of quantum light into the study of non-perturbative interactions may unlock revolutionary discoveries and applications.