In the early 1960s, the idea emerged that sub-atomic particles could be explained as natural excitations of a single quantum field. While this concept wasn’t adopted for its original purpose, the notion of a skyrmion, seen as a topologically stable field configuration, has found versatile applications in various fields, including condensed matter physics, acoustics, and optics. In these applications, skyrmions have been realized as localized fields and particles.
For the first time, researchers from the Structured Light Laboratory (School of Physics) at the University of the Witwatersrand in South Africa, in collaboration with string theorist Robert de Mello Koch from Huzhou University in China (previously from Wits University), have demonstrated the remarkable ability to perturb pairs of spatially separated yet interconnected quantum entangled particles without altering their shared properties.
Professor Andrew Forbes said, “The entanglement between our photons is malleable, like clay in a potter’s hands, but during the molding process, some features are retained.”
The nature of the topology investigated here is termed Skyrmion topology. In the realm of condensed matter physics, skyrmions are highly regarded for their stability and noise resistance, leading to groundbreaking advancements in high-density data storage devices.
Scientists aimed to see a similar transformative impact with our quantum-entangled skyrmions.
Lead author Pedro Ornelas, an MSc student in the structured light laboratory, said, “Our work presents a paradigm shift: the topology that has traditionally been thought to exist in a single and local configuration is now nonlocal or shared between spatially separated entities.”
Dr. Isaac Nape, a co-investigator, said, “Expanding on this concept, the researchers utilize topology as a framework to classify or distinguish entangled states. They envisage that “this fresh perspective can serve as a labeling system for entangled states, akin to an alphabet!”
“Similar to how spheres, doughnuts, and handcuffs are distinguished by the number of holes they contain, our quantum skyrmions can be differentiated by their topological aspects in the same fashion.”
The research team envisions this discovery as a powerful tool, potentially leading to the development of new quantum communication protocols. These protocols could leverage topology as an alphabet for quantum information processing, particularly across channels based on entanglement.
The discovery is significant as researchers have faced challenges preserving entangled states over time. The preservation of topology, even as entanglement decays, opens up the possibility of a new encoding mechanism that utilizes entanglement, even in scenarios with minimal entanglement where traditional encoding protocols may fail.
Journal Reference:
- Ornelas, P., Nape, I., de Mello Koch, R. et al. Non-local skyrmions as topologically resilient quantum entangled states of light. Nat. Photon. (2024). DOI: 10.1038/s41566-023-01360-4