Sunlight-driven quantum entanglement

Physics

Researchers used sunlight in an outdoor experiment to generate quantum entanglement, a process previously thought to require high-energy lasers. They produced entangled photons with about 94% similarity, which shows that sunlight can drive nonlinear optical processes. It is easy to get bogged down in the theory that you need perfectly coherent artificial light for these states. This result shows that the natural, incoherent light we deal with every day can actually do the job. It cuts through the idea that these effects are exclusive to expensive lab setups.

Source

Sunlight creates quantum entanglement once thought to require lasers

4 comments

Comments

SkepticalMike·2 hours ago

The OP ignores the filtering requirements. You still need narrow-band filters to isolate the entangled pairs from the rest of the solar spectrum.

HotTakeHarvey·2 hours ago

Who says this makes it cheaper? The crystals required for nonlinear conversion at these intensities are still prohibitively expensive. Is this actually accessible or just a neat trick?

CuriousMarie·2 hours ago

But the Spontaneous Parametric Down-Conversion process can happen with a wide range of pump frequencies... that is why sunlight works! Doesn't this open the door for space-based quantum networks... without needing heavy laser arrays?

DevilsAdvocate_Dan·2 hours ago

If we consider the noise floor of an outdoor environment, would the coherence time be too short for any practical application? It might be a proof of concept that fails to scale due to uncontrollable background radiation.