{"id":602266,"date":"2026-07-24T16:29:13","date_gmt":"2026-07-24T16:29:13","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/602266\/"},"modified":"2026-07-24T16:29:13","modified_gmt":"2026-07-24T16:29:13","slug":"what-happens-if-you-cut-a-photon-in-half-the-answer-is-trippy","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/602266\/","title":{"rendered":"What Happens if You Cut a Photon in Half? The Answer Is Trippy"},"content":{"rendered":"

Physicists tend to think of light in terms of photons: massless, elementary particles \u201ccarrying<\/a>\u201d the forces of nature. And elementary particles, like the photon, are indivisible. That is, there is no such thing as half a photon. Or is there?<\/p>\n

That was the question that three theoretical physicists tried to answer in a recent paper<\/a> published in Physical Review Letters, bluntly titled \u201cTruncated Photon.\u201d To be clear, the team understands that elementary particles like photons can\u2019t be cut into two. But consider this quantum shortcut: photons exhibit the behaviors of both waves and particles. As it turns out, there is a way to split a photon using this property\u2014although, in typical quantum weirdness, the product of this isn\u2019t anything you\u2019d expect.<\/p>\n

\u201cDespite being a simple question, it appears that it has not been asked before,\u201d the physicists, from the University of Oslo in Norway, wrote in the paper.<\/p>\n

Some primers <\/p>\n

The dual nature of light as both a particle and a wave was most famously demonstrated by British physicist Thomas Young in 1801. The double-slit experiment<\/a>, as it came to be called, showed how, when you shine a beam of light (\u201cparticles\u201d) through two parallel slits on a screen, you\u2019d get an interference pattern resembling the union of two ripples (\u201cwaves\u201d) on the other side.<\/p>\n

In the quantum realm, objects can also exist in superposition<\/a>. This is the phenomenon that Schr\u00f6dinger\u2019s Cat thought experiment attempted to demonstrate. A cat with a sealed box containing a poisonous substance could be dead or alive. But it\u2019s theoretically both\u2014in a superposition of states\u2014until we observe the cat by opening the box. In other words, the act of observation causes a quantum system to probabilistically fall into one state or the other.<\/p>\n

Now we truncate <\/p>\n

The latest study builds upon these quantum principles. As a wave packet, a photon would possess some spatial distribution. Using an optical shutter\u2014fast-moving mirrors that block or release light pulses\u2014it might be possible to effectively separate sections of this wave. Specifically, the shutter would transform the photon into a superposition of modes either traveling right or left, according to the paper.<\/p>\n

Using quantum field theory, the researchers calculated how this setup would affect the dynamics of a photon\u2019s waveform. Surprisingly, their results weren\u2019t that we now had two photons, or even a photon and a vacuum. Rather, what they got was a \u201ccomplicated state involving photon numbers up to infinity.\u201d Basically, \u201ccutting away a part of the photon\u201d resulted in a \u201cbunch of new photons,\u201d they wrote.<\/p>\n

In an accompanying Synopsis<\/a> commentary, the team explained that, in removing the mirror, a \u201ctug on the quantum field\u201d pulls out enough photons from the nearby vacuum. This forms a \u201csharp edge\u201d consisting of increasingly more superposed photons, until you get a quantum state of infinite photons.<\/p>\n

But wait, it gets weirder <\/p>\n

Here\u2019s the cherry on top. If you tried to measure the states on either side of the split wave packet, you\u2019d get measurements that look \u201cexactly like a single-photon state\u201d on the left and a vacuum on the right, except for a very narrow transition region, according to the paper. So, down on the quantum level, there\u2019s a constant, infinite flow of photons. But if you tried to measure it, you\u2019d see either one photon or nothing at all. (Yeah. Welcome to the quantum world.)<\/p>\n

\"QuantumA graph showing a truncated photon state, with a locally equivalent state to a single photon on the left and a vacuum to the right. The parallel bars in the middle represent a small \u201ctransition region.\u201d \u00a9 Rukan et al., 2026 <\/p>\n

\u201cThe truncated photon state is thus an example of a very complicated state that produces the exact same measurement statistics as very simple states, as long as one is interested only in local observables to the left or right of the transition region,\u201d the researchers added in the study.<\/p>\n

Again, the study is entirely theoretical; no actual photons were harmed during the course of this project. However, the exercise demonstrates a previously unexplored behavior of key concepts in quantum field theory. The experimental design isn\u2019t too complicated, so it wouldn\u2019t be impossible for experimentalists to replicate the calculations in real life.<\/p>\n","protected":false},"excerpt":{"rendered":"Physicists tend to think of light in terms of photons: massless, elementary particles \u201ccarrying\u201d the forces of nature.…\n","protected":false},"author":2,"featured_media":602267,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[77],"tags":[18,19,17,1098,133,3550],"class_list":["post-602266","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-eire","tag-ie","tag-ireland","tag-quantum-physics","tag-science","tag-theoretical-physics"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116975905992419364","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/602266","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=602266"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/602266\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/602267"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=602266"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=602266"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=602266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}