How should a theory of quantum theory of Gravity look like?

Answer 1

A theory of quantum gravity would ideally be a unified framework that combines the principles and predictive power of both quantum mechanics and general relativity. Here are some key features that such a theory should possess:

1. Quantum Nature of Gravity: The theory should explain gravity in terms of quantum fields and particles, similar to how other fundamental forces (e.g., electromagnetism) are described in quantum field theories.

2. Quantization of Spacetime: The theory should provide a quantum description of spacetime itself, indicating that spacetime is not continuous but rather made up of discrete or granular units.

3. Unification of Forces: It should attempt to unify all four fundamental forces (gravity, electromagnetism, and the strong and weak nuclear forces) into a single coherent framework.

4. Conservation of Information: The theory should uphold the principle of conservation of information, ensuring that no information is lost in any physical process.

5. Resolution of Singularities: Singularities, such as those found in the centers of black holes or at the beginning of the universe, should be resolved or avoided through the theory, providing a more complete and consistent understanding.

6. Predictions & Experiments: The theory should make testable predictions that can be experimentally verified or falsified, allowing for empirical validation.

7. Mathematical Consistency: It should possess mathematical consistency and coherence, providing a formal framework that allows for precise calculations and predictions.

It's important to note that formulating a complete theory of quantum gravity is an ongoing and active area of research in theoretical physics. Various approaches, such as string theory, loop quantum gravity, and causal sets, are being pursued to address this profound challenge.