Image Courtesy: Phys.org
A new theoretical study has explored an unusual question at the heart of quantum physics: what would happen if it were possible to cut a single photon in half? The answer, researchers say, is far stranger than simply producing two smaller pieces of light.
In work published in the journal Physical Review Letters, physicist Johannes Skaar and colleagues found that attempting to split a photon using an ultra-fast optical shutter would not create two partial photons. Instead, the process would generate a quantum state containing an infinite number of photons existing in superposition.
Photons are considered elementary particles, meaning they have no known internal structure and cannot be broken into smaller components. However, because quantum particles behave both as localized particles and as waves spread across space, the researchers investigated what might happen if part of a photon’s wave-like structure were abruptly blocked during its journey.
Using quantum field theory calculations, the team modeled a scenario in which an extremely fast optical shutter intercepts a photon mid-pulse. Rather than neatly separating the photon into distinct sections, the rapid interruption disturbs the quantum fluctuations that naturally exist in empty space.
Those fluctuations are key to the surprising result. In quantum mechanics, a vacuum is not truly empty but is filled with constantly fluctuating electromagnetic fields. The researchers found that disturbing these fields can trigger the spontaneous creation of additional photons, leading to an infinitely complex quantum state rather than a simple split.
Despite this mathematical explosion of particles, an observer examining only the regions immediately surrounding the shutter would still perceive something that looks remarkably ordinary: a single photon on one side and empty space on the other. The bizarre underlying structure remains hidden within the broader quantum description of the system.
The findings highlight how dramatically quantum behavior diverges from everyday intuition. While the work is purely theoretical, it offers new insight into how quantum information is distributed and how measurements interact with the underlying fabric of quantum fields.
The researchers now plan to investigate whether similar effects emerge when multiple photons are involved or when the same framework is applied to other elementary particles, such as electrons. The work could help deepen understanding of quantum measurement, particle creation, and the nature of empty space itself.