The world of quantum possibilities refers to the idea in quantum mechanics that subatomic particles exist in a superposition of all possible states until a measurement is made. In other words, until we observe a quantum particle, it does not have a definite position or momentum, but rather it exists in a range of possible states simultaneously.
This is one of the earliest and most famous interpretations of quantum mechanics developed by Niels Bohr and Werner Heisenberg in the 1920s. It states that a particle's quantum state is uncertain until it is observed and collapses into a definite state.
In the Copenhagen interpretation, the wave function is interpreted as a probability distribution, which tells us the probability of finding the system in different states when a measurement is made. The act of measurement is seen as a physical interaction between the quantum system and the measuring device, which causes the wave function to collapse into a single state. The Copenhagen interpretation has been extremely successful in explaining a wide range of quantum phenomena, including the behavior of atoms, molecules, and subatomic particles.