Objective collapse models of quantum mechanics and the block universe are not inherently incompatible, but they can present challenges when combined.
The block universe, also known as the "block time" or "eternalism," is a philosophical view of time that suggests that past, present, and future all exist simultaneously as a static four-dimensional block. According to this view, the entire history of the universe is already fixed and unchanging, similar to a movie reel where every frame exists concurrently.
Objective collapse models, on the other hand, propose modifications to standard quantum mechanics by introducing mechanisms that cause the collapse of the wave function. These models aim to explain the transition from quantum superposition to definite measurement outcomes, as observed in macroscopic objects. Examples of such models include the GRW (Ghirardi-Rimini-Weber) and CSL (Continuous Spontaneous Localization) theories.
The challenge arises when attempting to reconcile the dynamical evolution of objective collapse models with the static nature of the block universe. Objective collapse models introduce non-unitary and irreversible processes, which can be at odds with the time symmetry and determinism often associated with the block universe.
One possible resolution to this challenge is to interpret the collapse events as subjective experiences within the block universe. In this view, the collapse of the wave function could be considered a subjective observation by an observer within the block universe, while the underlying quantum dynamics still adhere to the deterministic and timeless nature of the block universe.
However, it is important to note that the compatibility or incompatibility of objective collapse models and the block universe remains a topic of ongoing debate and exploration among physicists and philosophers. Different interpretations and viewpoints exist, and further research is needed to fully understand their implications and potential resolutions.