The interplay between quantum mechanics and gravity is an area of active research and remains an open question in theoretical physics. The current understanding is that gravity, as described by Einstein's theory of general relativity, is not explicitly included in the framework of quantum mechanics. Consequently, there is no widely accepted theory that fully combines quantum mechanics and gravity into a unified framework.
The effects of gravity on a quantum superposition are not well understood because we lack a complete theory that encompasses both quantum mechanics and gravity. However, there are some aspects and hypotheses that researchers have explored:
Quantum field theory in curved spacetime: One approach is to study quantum field theory in curved spacetime, where the gravitational effects of a classical curved background spacetime are considered. This framework allows for some understanding of how quantum fields, which are described by quantum mechanics, interact with gravity. However, this approach does not fully capture the quantum nature of gravity itself.
Quantum gravity and superpositions: The search for a theory of quantum gravity, which would encompass both quantum mechanics and gravity at a fundamental level, is ongoing. Some proposed theories, such as string theory or loop quantum gravity, attempt to reconcile quantum mechanics and gravity. These theories suggest that at extremely small scales, where quantum effects dominate, spacetime itself may exhibit quantum behavior. In such a framework, it is possible that the superposition of quantum states could be affected by gravitational interactions.
Quantum entanglement and gravity: Gravity poses challenges for the entanglement of quantum systems. The formation and preservation of entanglement in the presence of gravitational interactions have been subjects of investigation. It is speculated that gravitational interactions, such as the curvature of spacetime, could affect the entanglement between quantum particles or systems, potentially altering their superposition properties.
It's important to note that our current understanding of these topics is limited, and a complete and consistent theory of quantum gravity is still an active area of research. The effects of gravity on quantum superposition remain uncertain until a more comprehensive theory that unifies quantum mechanics and gravity is established.