(April 28, 2022 at 3:18 pm)JairCrawford Wrote:(April 28, 2022 at 11:22 am)polymath257 Wrote: Which does have some appeal, I admit.
Still, we *know* that quantum gravity effects will be relevant at some point, so this type of splicing together may not be as straightforward as it appears in just GR.
Do you think something like the graviton could be the answer? Is there potential to discover a graviton at the LHC like we did with the Higgs boson?
In quantum theory, every wave phenomenon has a particle aspect to it (wave/particle duality) and vice versa.
We know gravitational waves exist, so there should be a corresponding particle. That particle is the graviton.
The problem is that the waves we have been able to detect correspond to very low energy gravitons and many, many of them. So it is impossible for us to detect a single graviton in this way. But, to get to the high energies required to be able to do this, we would have to get particle energies *far* higher than anything the LHC can produce (by many several of magnitude).
So, no, there is no potential to find gravitons at the LHC: the energies required are just too high. All energies at the LHC are still well within the range of classical gravity (a la general relativity).
Getting a good theory of the graviton is essentially the same thing as getting a good theory of quantum gravity. And yes, that is what we need to answer some fundamental questions.
When I was young, the unification of gravity and quantum mechanics was a BIG unsolved problem. Now, we at least have some theories that manage to merge the two. The problem is that we have no way to get to the energies required to test them and the different models give different answers to questions we are curious about.
So, we just don't know.
