According to the principles of quantum mechanics, the behavior of particles on a microscopic scale, such as electrons or photons, can exhibit wave-particle duality. This means that they can exhibit both particle-like and wave-like properties. The famous double-slit experiment demonstrates this phenomenon.
In the double-slit experiment, particles (e.g., electrons or photons) are directed towards a barrier with two slits. If a particle is sent through one of the slits, it can indeed exhibit interference patterns characteristic of wave behavior. However, it is important to note that the particle itself passes through only one of the slits at any given time.
When a particle is sent through one slit, it does not simultaneously pass through the other slit. The interference pattern observed on the detection screen occurs because the particle behaves as a wave, and waves can interfere with each other. The wave nature of the particle allows it to simultaneously explore multiple paths, resulting in an interference pattern when the waves associated with those paths overlap.
Once the particle is detected or measured, it localizes to a specific position, behaving like a particle and no longer exhibiting the interference pattern. The act of detection or measurement collapses the wave function, forcing the particle to choose a definite position.
In summary, particles do not pass through both slits simultaneously, but they exhibit wave-like behavior that allows them to interfere with themselves and produce an interference pattern on a detection screen.