Can We Really Create Infinite Photons? Physicists Reveal What Might Happen if We Try to Cut Light in Half - ScienceAlert

What the report says

ScienceAlert reports that physicists at the University of Oslo have examined a counterintuitive question in quantum optics: what would happen if part of a photon’s wave-like presence were abruptly blocked or removed. The work, published in Physical Review Letters, does not mean an elementary particle can literally be sliced in two. Instead, the researchers modeled a photon interacting with an optical shutter or mirror that is removed while reflecting it.

According to the report, the calculation suggests that “truncating” a photon can create a complex quantum state involving many possible photon numbers. When measured, the result could be zero photons, a small number, or many, with the mathematical description allowing states extending upward without a fixed maximum. Johannes Skaar, a theoretical physicist at the University of Oslo and a study co-author, told ScienceAlert that this should not be read as producing an infinite expected number of photons. A slow shutter removal would produce few photons, while a faster one would produce more, but an infinite result would require an impossible infinitely fast process.

The article also notes that the effect is connected to quantum field theory’s treatment of the vacuum: even apparently empty space can be transformed into a state containing real photons under changing boundary conditions. Skaar said the setup is not necessarily impractical because narrow-band photons can extend over very long distances, reducing the speed required of the mirror.

The finding matters because it probes how light behaves when its wave-like structure is disturbed, adding to long-running questions raised by photon wave-particle duality. ScienceAlert emphasizes that the predicted state would look different depending on where it is observed: like one photon on one side, no photon on the other, and a more complex photon mixture near the transition region.