The wave function collapse, also known as wave function reduction or quantum measurement, refers to the phenomenon in quantum mechanics where the superposition of possible states of a system "collapses" into a definite state upon measurement or interaction with the external world. This collapse is often associated with the act of observation or measurement by a conscious observer.
The interpretation of wave function collapse is a subject of ongoing debate and different interpretations exist within quantum mechanics. One interpretation, known as the Copenhagen interpretation, suggests that the wave function represents a probabilistic description of a quantum system, and the collapse occurs when a measurement is made, revealing a specific outcome. According to this interpretation, the collapse does not necessarily imply that the entire universe is described by a single large wave.
Other interpretations, such as the Many-Worlds interpretation and the Bohmian mechanics interpretation, propose different explanations for the nature of the wave function collapse. In the Many-Worlds interpretation, the collapse is seen as an apparent phenomenon, and all possible outcomes actually occur in separate branches of reality, resulting in a "splitting" of the universe into multiple parallel universes. In Bohmian mechanics, the wave function collapse is replaced by a deterministic process, where particles have definite positions but are guided by a hidden variable.
It's important to note that these interpretations are philosophical perspectives and attempts to understand the mathematical formalism of quantum mechanics. The true nature of the wave function collapse and its implications for the nature of the universe are still subjects of active research and philosophical inquiry.