In a triple-slit experiment, the presence of multiple slits introduces interference effects that are different from the double-slit experiment. If you observe the particle coming out of one specific slit, the interference pattern will not revert to the double-slit pattern.
In the double-slit experiment, when both slits are open, interference between the two diffracted waves creates an interference pattern consisting of bright and dark fringes on the screen behind the slits. This pattern is a result of the constructive and destructive interference of the waves.
In a triple-slit experiment, the presence of three slits adds more complexity to the interference pattern. The resulting pattern will typically have multiple sets of interference fringes, which arise from the interference of multiple diffracted waves from the different slits. These patterns are distinct from the double-slit pattern.
If you observe the particle coming out of one slit in the triple-slit experiment, it means you are effectively blocking the other two slits. As a result, the interference effects from those slits will not contribute to the observed pattern. However, the remaining two slits will still create their interference pattern, resulting in a modified pattern compared to the three-slit case. This modified pattern will not revert to the simple double-slit pattern but will be influenced by the remaining open slit and its interference with the particle passing through it.
It's worth noting that the behavior of particles in quantum experiments is probabilistic, and the observation of a particle coming out of one slit can affect the overall experiment and potentially disturb the interference pattern in unpredictable ways. The precise outcome depends on the specific experimental setup and conditions.