In the double-slit experiment, when a photon passes through both slits and exhibits interference patterns, the frequency of the photon does not change. The interference patterns observed in the experiment arise from the wave-like nature of light and the superposition of different possible paths that the photon can take.
In the experiment, individual photons are sent towards a barrier with two slits. Behind the barrier, a screen is placed to observe the pattern formed by the photons that pass through the slits. When only one slit is open, the photons create a simple pattern on the screen. However, when both slits are open, an interference pattern emerges, indicating that the photons have interfered with each other.
This interference pattern occurs because each photon can be thought of as a wave that passes through both slits simultaneously and then interferes with itself. The superposition of the waves from the two slits creates regions of constructive and destructive interference, resulting in the observed pattern on the screen.
It's important to note that the frequency of the photon, which corresponds to its energy, remains the same throughout the experiment. The interference patterns arise from the wave nature of light and the probability amplitudes associated with different paths the photon can take. At no point does energy get duplicated or created in the process.
The double-slit experiment is a fundamental demonstration of the wave-particle duality of light, and it showcases the probabilistic nature of quantum mechanics, where particles can behave as waves and exhibit interference effects.