In the double-slit experiment, which is typically conducted with particles such as electrons or photons (light particles), the wave-particle duality of quantum mechanics becomes evident. The behavior of particles can be described by a wave function, which represents the probability distribution of the particle's position or other observable properties.
When particles pass through the double slits one by one, they can exhibit interference patterns on the screen behind the slits, suggesting wave-like behavior. However, if a measurement is made to determine which slit a particle passes through, the interference pattern disappears, and the particles behave more like individual particles, showing a particle-like pattern on the screen.
For light, the wave function collapse can indeed occur if a measurement is made to determine which slit the photons pass through. If a light detector is placed at or near the slits to detect the photons, the act of measurement will disturb the photons and collapse their wave functions. This disturbance destroys the interference pattern, and the photons behave more like particles, resulting in a particle-like pattern on the screen.
Therefore, the presence of a light detector can lead to the disappearance of the interference pattern in the double-slit experiment with light, similar to what happens with other particles. This phenomenon demonstrates the wave-particle duality and the role of observation or measurement in quantum mechanics.