Scientists Found a Quantum Surprise in Ordinary Light

By Chinese Society for Optical Engineering January 3, 2025

Collected at: https://scitechdaily.com/scientists-found-a-quantum-surprise-in-ordinary-light/

Scientists have revealed quantum coherence in classical light fields, challenging traditional physics boundaries.

Through advanced techniques, they isolated subsystems exhibiting quantum interference, paving the way for scalable quantum technologies and new insights into many-body systems.

Bridging Classical and Quantum Physics

Understanding the boundary between classical and quantum physics has long been a fundamental challenge in science. Traditionally, thermal light fields have been considered purely classical. However, by breaking these fields into smaller multiphoton subsystems, researchers made a surprising discovery: quantum coherence. This phenomenon, which includes particle interference, was thought to be exclusive to quantum systems, yet it emerged from a classical light source.

Fragmenting Light Fields into Quantum Subsystems

Using advanced techniques such as photon-number-resolving detection and orbital angular momentum (OAM) measurements, the team transformed a classical pseudothermal light field into isolated multiphoton subsystems. Within these subsystems, they observed two contrasting behaviors:

1. Classical Coherence: The majority of subsystems behaved predictably, consistent with the principles of classical optics.
2. Quantum Coherence: A smaller subset exhibited interference patterns reminiscent of quantum phenomena observed in entangled photon systems.

Hidden Quantum Dynamics in Classical Systems

“This discovery shows that even a classical system hosts hidden quantum dynamics,” explained Prof. Chenglong You, the study’s lead author. “We’ve unveiled novel mechanisms to isolate quantum systems, which could lead to more robust quantum technologies.”

Opportunities for Quantum Technology Development

The ability to extract quantum behaviors from classical systems offers new opportunities for developing advanced quantum technologies. From quantum imaging to quantum-enhanced sensors, this work provides a fundamental platform for mitigating decoherence and accessing quantum properties in open systems.

The findings highlight universal quantum behaviors in many-body systems with broad applications, including condensed matter physics and quantum information science. Moving forward, this platform could be instrumental in engineering scalable quantum technologies at room temperature.

Reference: “Isolating the classical and quantum coherence of a multiphoton system” by Chenglong You, Mingyuan Hong, Fatemeh Mostafavi, Jannatul Ferdous, Roberto de J. León-Montiel, Riley B. Dawkins and Omar S. Magaña-Loaiza, 27 November 2024, PhotoniX.
DOI: 10.1186/s43074-024-00153-4

The study was a collaborative effort led by researchers from Louisiana State University and Universidad Nacional Autónoma de México. It was supported by funding from the U.S. Army Research Office, the Department of Energy, the National Science Foundation and DGAPA‑UNAM.