{"id":576877,"date":"2026-08-06T20:40:13","date_gmt":"2026-08-06T20:40:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/576877\/"},"modified":"2026-08-06T20:40:13","modified_gmt":"2026-08-06T20:40:13","slug":"physicists-harness-sunlight-for-quantum-entanglement","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/576877\/","title":{"rendered":"Physicists harness sunlight for quantum entanglement"},"content":{"rendered":"

At the foundation of photonic quantum computing<\/a> are pairs of light particles. Linked together through a process called quantum entanglement<\/a>, these so-called entangled particles mirror each other, no matter the distance between them. And now researchers have shown that good old sunlight can create these specially entwined particles.<\/p>\n

In a study published in Optica<\/a>, a team led by researchers at the University of Ottawa and the Max Planck Institute for the Science of Light (MPL) in Erlangen, Germany, generated pairs of entangled photons using nothing more than focused sunlight.<\/p>\n

\u201cWhat we want is really to make quantum technology more and more accessible for everybody,\u201d says Cheng Li, who co-led the work as a graduate student at the University of Ottawa and is now at Lawrence Berkeley National Laboratory. \u201cIf it\u2019s possible with sunlight, then you can virtually do it anywhere.\u201d<\/p>\n

On supporting science journalism<\/p>\n

If you’re enjoying this article, consider supporting our award-winning journalism by subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n

For decades, physicists have relied on high-energy lasers beamed through special crystals to produce entangled photons\u2014a process called spontaneous parametric down-conversion. The incoming light beam is almost always a laser because physicists long assumed that producing such a strongly ordered connection would require strongly ordered light: A laser\u2019s waves oscillate in lockstep, at a single color. Sunlight, by contrast, is a jumble of wavelengths headed in every direction.<\/p>\n

Lasers also come at a high energy cost. They run on electricity, demand constant stabilization and shed much of their power as heat. Physicist Robert Boyd of the University of Ottawa, the new study\u2019s senior author, and his colleagues had already begun probing whether the laser was truly necessary\u2014showing, in theory and in light-emitting diode (LED) experiments, that incoherent light could still yield entanglement, so long as the entanglement depends on a property of light that doesn’t depend on color or direction.<\/p>\n

Sunlight is free, which is why it was so appealing. \u201cWe take out the electrical-to-optical conversion part of entanglement generation,\u201d Li says. \u201cWe go straight from light to light.\u201d Focusing diffuse sunlight onto a millimeter-scale crystal posed its own challenge. Study co-author Hanieh Fattahi\u2019s team at MPL built an all-glass, cone-shaped solar concentrator that funnels light from a window-sized Fresnel lens into a very thin optical fiber.<\/p>\n

\"\"<\/p>\n

Cheng Li is shown with the outdoor experimental setup. The sunlight concentration module, including the Fresnel lens and the solar concentrator, is mounted on a solar-tracking motor to ensure stable power delivery. The entanglement generation and detection setup, including the nonlinear crystal and the single-photon detectors, are shielded in an optical enclosure placed inside a blackout tent.<\/p>\n

Jasvinder Brar, Max Planck Institute for the Science of Light<\/p>\n

In outdoor tests at MPL that were conducted over three days, the system\u2019s resulting photon pairs matched a perfectly entangled state with a fidelity of roughly 94 percent and violated Bell\u2019s inequality\u2014a statistical test used to determine if quantum behavior is confirmed \u2014by a modest margin that the team partly attributes to weak seasonal sunlight and passing clouds. The entanglement quality fell slightly short of the best laser-driven sources, but Li ascribes that gap to distortions from the optical components\u2014something further engineering can fix\u2014rather than to the sunlight\u2019s incoherence.<\/p>\n

\u201cThis is a proof of principle,\u201d Li says. Now the team is working to boost the source\u2019s brightness and entanglement quality toward a field-deployable device.<\/p>\n

One day, such a system could help satellites generate quantum encryption<\/a> keys from the sunlight streaming past them, he says. And with data centers already straining power grids, Li argues, quantum technology\u2019s energy appetite is a problem that it is best to solve before it truly arrives.<\/p>\n

\u201cSunlight is just there,\u201d he says. \u201cWe just cut out the middleman and let sunlight do all the work.\u201d<\/p>\n

\"\"<\/p>\n

Using a new cone-shaped solar concentrator, researchers showed that sunlight can be used to create entangled photons. This could one day enable satellites to create secure encryption keys using the sunlight already abundant in space.<\/p>\n

Florian Sterl<\/p>\n

It\u2019s Time to Stand Up for Science<\/p>\n

If you enjoyed this article, I\u2019d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n

I\u2019ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n

If you subscribe to Scientific American<\/a>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n

In return, you get essential news, captivating podcasts<\/a>, brilliant infographics, can’t-miss newsletters<\/a>, must-watch videos, challenging games<\/a>, and the science world’s best writing and reporting. You can even gift someone a subscription<\/a>.<\/p>\n

There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":"At the foundation of photonic quantum computing are pairs of light particles. Linked together through a process called…\n","protected":false},"author":2,"featured_media":576878,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[85,46,370,141],"class_list":["post-576877","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-il","tag-israel","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/576877","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=576877"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/576877\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/576878"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=576877"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=576877"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=576877"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}