The concept of parallel universes, also known as the many-worlds interpretation, is one possible interpretation of quantum mechanics, but it is important to note that it is not the only interpretation, and it remains a topic of debate and speculation among physicists.
In the many-worlds interpretation, when a quantum system is in a superposition of states, instead of collapsing into a single state upon measurement, the universe splits into multiple branches, each corresponding to one of the possible outcomes. This interpretation suggests that all possible outcomes of a measurement actually occur in different parallel universes, with each universe containing a different outcome.
While the many-worlds interpretation offers an explanation for the behavior of superposition, it does not provide a direct explanation for entanglement. Entanglement involves the correlation between the states of two or more particles, and it is a phenomenon that goes beyond the notion of branching universes in the many-worlds interpretation.
Entanglement is typically explained within the framework of quantum mechanics itself, without invoking the concept of parallel universes. It is regarded as a fundamental feature of quantum mechanics, where particles become interconnected in such a way that the state of one particle cannot be described independently of the state of the other(s). The entangled particles are treated as a single quantum system, and measurements made on one particle can instantaneously affect the state of the other particle, regardless of the distance between them.
So, while the many-worlds interpretation can provide an explanation for the superposition of quantum systems, the concept of parallel universes does not directly explain entanglement. Entanglement is a distinct aspect of quantum mechanics that requires its own explanation within the framework of quantum theory.