A pattern that survives disruption: Penn chip imprints robust "skyrmions" on photons
A University of Pennsylvania chip creates entangled photons carrying a pattern that persists even after the entanglement is destroyed. This could enable more reliable quantum networks.
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Future quantum networks are meant to transmit information using entangled particles of light – but entanglement is very fragile. A team led by Professor Liang Feng of the University of Pennsylvania's School of Engineering and Applied Science reports another route in the journal Nature Physics (DOI 10.1038/s41567-026-03487-x): so-called skyrmions, swirl-like topological patterns in the polarisation of light. The university presented the work on 30 October.
The chip generates a pair of entangled photons and imprints a skyrmion pattern on one of them, which the researchers then transferred to the quantum state shared by both photons. In the experiment, the pattern's topological property remained intact even when disruption had already destroyed the entanglement; it broke down only under even stronger disruption. Another form of quantum correlation, known as quantum discord, also persisted.
"We've shown that these patterns can survive without entanglement," says Feng. This could lay the groundwork for much more reliable quantum networks. The chip was fabricated at the university's nanotechnology centre after nearly five years of development; researchers from South Africa and Singapore were also involved. The release does not give specific measured values.