How Do Gravitons and Photons Compare in Quantum Theory?

[Naty1]

Based on the following excerpt, I'd appreciate any general comments/observations and then follow with a specific question.

Leonard Susskind says in THE BLACK HOLE WAR, 2008, PG 347 :

Richard Feynman showed up with a quantum theory of forces...electrically charged particles can emit and absorb photons...every form of matter emits and absorbs gravitons...an electron emits and absorbs about 10¹⁹ photons every second (reflecting the electrical force charge#) and a single electron on average takes more time than the entire age of the universe to emit a single graviton (reflecting the force of gravity#).

#: my parenthetical comment

I knew physics was crazy, but that just seems "over the horizon" crazy!

Q: In laymans terms how does quantum theory reflect gravity effects from energy rather than mass? In other words, does it take into account the gravitational equivalency between mass and energy via gravitons... or is there another process?

 

[humanino]

Hi Naty1,

if you have access to Weinberg's book, you may start the reading of chapter 13 in the first volume. He writes there much better than I could repeat. I may also attempt to present the lines of reasoning if you do not have access to it.

 

[Entropia]

First of all, I would like to say that the concept of gravitons is still a theoretical concept and has not been experimentally proven yet. It is a part of the theory of quantum gravity, which is still being studied and explored by scientists.

To answer your question, the theory of quantum gravity suggests that gravity is not a force between masses, but rather a curvature of spacetime caused by the presence of mass and energy. In this theory, gravitons are thought to be the particles that mediate the force of gravity, just like how photons mediate the electromagnetic force.

In quantum theory, energy and mass are considered interchangeable and can be converted into each other. This is known as the mass-energy equivalence, famously described by Einstein's equation E=mc^2. Therefore, the concept of gravitons also takes into account the equivalence between mass and energy, as they are both sources of gravity.

However, as mentioned earlier, the existence of gravitons is still a theoretical concept and more research is needed to fully understand the role of these particles in the theory of quantum gravity. I hope this helps to answer your question.