B Boundary between Quantum and Relativity

[rharrex]

At what point does quantum physics cease and general relativity take over. Where is the boundary? Is it a quantum of mass?

 

[A. Neumaier]

Quantum and Relativity is not a dichotomy. In relativistic quantum field theory you have both Quantum and Relativity.

Also there is no takeover of general relativity at some point, but the need to find a synthesis of quantum field theory and general relativity.

 

[Delta2]

Quantum Physics and Relativistic Quantum Physics rule in the realm of the microscopic world where the effect of gravitational field is negligible. This means that they can give absolutely satisfying explanations of some phenomena of the microscopic world like quantum tunnelling for example, where relativity alone fails miserably.

On the other hand Relativity takes over in the realm of the macro-macroscopic world that is in the case of planets, stars, solar systems, galaxies and universe as a whole. The main reason for this is that Relativity handles the gravitational field and its effect in the curvature of space-time extremely well, while on the other side a theory of quantum gravity is plagued with many problems (its not re-normalizable as we say in quantum physics).

In between, in our daily lives here on planet earth, both quantum physics and relativity give satisfying explanations though a bit different , in the various phenomena of our daily lives like for example how mobile phones and telecommunications and computers operate. That is because these phenomena can be explained using classical physics, and because quantum physics and relativity are different extensions build on the same core of classical physics.

 

[bhobba]

Everything is quantum including gravity. There is no point where one takes over - its quantum all the way.

Its a misconception that QM and GR are in conflict:
https://arxiv.org/abs/1209.3511

The issue is - what goes on below the Plank scale.

Right now who knows - QM may break down, string theory take over, we simply do not know - yet.

But up until about the Plank scale no-problemo - at least as far as I know. But its likely things will be found where its not true just like statistical mechanics and black-body radiation then we will have a new and likely swift physics revolution - it will be the time of wonder-boy physicists such as a new Einstein, Dirac, Heisenberg etc etc.

Thanks
Bill