Brazilian Theory Proposes Particle-Only Explanation for Double-Slit Interference

Researchers from the Federal University of São Carlos in Brazil proposed a novel theoretical interpretation of the double-slit experiment in an April 2025 publication, suggesting the interference pattern can be entirely explained by considering photons exclusively in distinct quantum states, thereby bypassing the need to invoke light's wave nature.

The analysis, led by Celso J. Villas-Boas and his collaborators, posits that the observed interference arises from 'dark states' of photons that do not interact with the detector, which accounts for the dark fringes, while 'bright states' correspond to the light fringes. This framework offers a distinct theoretical pathway for understanding the experimental observations by reframing destructive interference through these non-interacting quantum states.

This theoretical development directly confronts wave-particle duality, a foundational concept in modern physics, by asserting that the pattern is fully explicable by analyzing only the distinct quantum states of the photons. The researchers conclude that dark regions of the pattern still contain photons, but they exist in a state that prevents detection upon measurement.

The mathematical framework developed by the Brazilian team suggests the observed pattern results from statistical probabilities associated with the photon's quantum state upon reaching the detection screen, rather than the superposition of wave functions traversing both slits simultaneously. The research was published in the journal Physical Review Letters in April 2025.

The application of 'dark states' to fully explain the double-slit pattern without recourse to wave propagation is the novel aspect advanced by the Federal University of São Carlos team. This approach aligns with a broader scientific engagement in 2025 to refine the understanding of quantum theory foundations, including related work from institutions such as the Stevens Institute of Technology.

The team's analysis suggests that thermal radiation may also possess these unobservable dark states, potentially opening avenues for future experimental verification of this particle-only model. The double-slit experiment, first demonstrated by Thomas Young in 1801, remains a central phenomenon illustrating the counterintuitive nature of the quantum world.