Cutting a photon in two creates an infinite swarm of particles

June 2, 2026 report Cutting a photon in two creates an infinite swarm of particles Sam Jarman Author Gaby Clark Scientific Editor Robert Egan Associate Editor By definition, elementary particles can't be broken into smaller pieces. But in a new theoretical study published in Physical Review Letters, Johannes Skaar and colleagues have revealed what would happen if you tried anyway for a single photon. The answer is deeply strange: attempting to cut a photon in two wouldn't produce two smaller photons, but instead conjure an infinite number of them out of thin air. Impossible to cut in half Like any quantum particle, a photon exists simultaneously as a single, localized particle, and an extended wave, spread out across space. For their investigation, Skaar's team considered what would happen if a single photon passed through an optical shutter—essentially a very fast mirror that can be switched on and off to block part of a pulse of light. If the shutter was fast enough, it could intercept the photon mid-pulse, snipping off part of this extended wave. To find out what would happen afterward, the researchers applied quantum equations that describe how the photon's underlying electromagnetic field behaves at the quantum level. Specifically, their analysis tracked precisely how the photon's quantum state would be transformed by the shutter's intervention. Infinite superposition Rather than producing a photon on one side and a vacuum on the other, the shutter generates something far more strange and complex: a superposition of states containing infinitely many photons simultaneously. This happens because, in quantum mechanics, empty space isn't truly empty—in reality, it seethes with fluctuations in the electromagnetic field. By rapidly switching the shutter, the team found that these fluctuations are disturbed—and in doing so, they spontaneously create new photons. Crucially though, if you were to look only at the region immediately either side of where the shutter operated, the state would appear deceptively normal: indistinguishable from a single photon on one side, and a simple vacuum on the other. Deeper quantum investigations The result offers a striking illustration of how quantum particles behave differently from everyday objects, and raises deeper questions about how quantum systems are measured and how information is localized in space. In their future research, Skaar and his colleagues now plan to push further—exploring whether the same bizarre physics would apply when more than one photon is involved, or when the analysis is extended to other elementary particles, such as electrons. Written for you by our author Sam Jarman, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. Publication details Isak Cecil Onsager Rukan et al, Truncated photon, Physical Review Letters (2026). DOI: 10.1103/94pm-hp34. On arXiv: arxiv.org/abs/2510.21636 Journal information: Physical Review Letters , arXiv Key concepts Optics & lasersQuantum correlations, foundations & formalismQuantum field theoryGauge bosons© 2026 Science X Network