In the double-slit experiment, when firing photons one by one, the interference pattern that emerges is a result of the probabilistic nature of quantum mechanics. Each individual photon behaves as a wave and exhibits wave-particle duality.
When firing photons one by one, you are essentially aiming them at the double-slit apparatus itself. The photons are directed toward the slits, and as they pass through the slits, they diffract and create an interference pattern on a screen placed behind the slits. This interference pattern arises due to the superposition of the wave-like nature of photons.
Interestingly, even when photons are sent through the apparatus one at a time, they can still exhibit interference behavior. This phenomenon can be explained by the concept of quantum superposition, where the photon simultaneously passes through both slits as a wave, interfering with itself. As each photon arrives at the screen, it contributes to the overall interference pattern. Over time, as more photons are detected, the interference pattern becomes evident.
The double-slit experiment demonstrates the wave-particle duality of particles at the quantum level and highlights the probabilistic nature of quantum mechanics.