The depiction of wave-particle duality with a longitudinal wave in a diagram may not accurately represent the nature of light or the double-slit experiment. Light, including photons, is typically described as a transverse electromagnetic wave rather than a longitudinal wave.
In the double-slit experiment, the wave-particle duality of light is better understood by considering the probabilistic nature of quantum mechanics. Photons exhibit wave-like properties, and the probability of finding a photon at a particular point on the screen is determined by the interference of these waves.
The probability distribution of finding a photon at a particular location on the screen behind the double slits forms an interference pattern. This pattern arises due to the superposition of the waves emanating from the two slits, which interfere constructively and destructively. The regions where the interference is constructive correspond to the bright fringes, while the regions of destructive interference result in dark fringes.
The probability of finding a photon is not zero in the regions between the bright fringes. Rather, the probability decreases, becoming smaller as you move away from the bright fringes. However, it is important to note that even in the dark regions, there is still a finite probability of detecting a photon.
The specific shape of the interference pattern is determined by the characteristics of the double-slit arrangement, the wavelength of the light, and the distance between the slits and the screen. It does not imply that there are points with zero probability of finding a photon before the slits.
Overall, the double-slit experiment demonstrates the wave-like behavior of photons and the interference patterns that emerge. It's important to remember that the interpretation of these phenomena is based on probability distributions rather than the classical notion of particles following definite trajectories.