Two separate, distant light sources have been synchronized to emit photons that are nearly perfect identical twins.
April 29, 2026
Original Paper
Near-identical photons from distant quantum dot-cavity devices
arXiv · 2604.25615
The Takeaway
Quantum dot-cavity devices can now produce photons with 88 percent indistinguishability even when the devices are completely separate units. Getting photons from different sources to behave as if they came from the same source is a major hurdle for quantum networking. This result reaches the theoretical limit of what the sources themselves are capable of producing. It means we can now link up many different quantum devices to form a quantum internet that spans long distances. This achievement proves that high-performance quantum communication systems can be built using modular, mass-produced components.
From the abstract
Scalable optical quantum technologies require interference between large numbers of indistinguishable single-photons emitted by independent sources. Semiconductor quantum dots are known to be excellent on-demand sources of single-photons. They show record efficiency when inserted into optical cavities to control their spontaneous emission and generate trains of near identical photons over microsecond timescales. However, generating perfectly identical photons from distant cavity-based sources ha