Undergrad Quantum field and mediating particles

Click For Summary
The discussion centers on the relationship between mediating particles and the forces they represent in quantum field theory. It highlights that while electromagnetic forces are mediated by massless photons, the question arises about gravity, which also has an infinite range. Participants clarify that gravitational forces are thought to be mediated by massless particles called gravitons, which have a spin of 2. The original poster expresses relief upon discovering this information, confirming their understanding was on the right track. This exchange emphasizes the importance of understanding quantum gravity and the role of gravitons in mediating gravitational forces.
alivedude
Messages
58
Reaction score
5
I'm not sure if I posted this in the right category, it's something that came up just after the quantum mechanics section so I just chose this one.

I've come across something that I simply can not find an answer for on my own. I'm taking Modern Physics course and the last chapter is some introductory to Quantum field theory and they explain how you can treat forces as exchange of particles. From the energy-time uncertainty principle they go on and explain that if the mediating particle has mass, the range of the force is limited. This suits well if I think about electromagnetic forces. Since photons are massless the force should reach infinitely far, and indeed that is the case.

But what about gravity? Shouldn't there be some massless mediating particle in this case as well since gravitational force also reaches infinitely far or is it something that I misunderstood? I can't find anything about it in my very limited book. I'm only a second year undergrad so don't the stuff I read isn't that advanced.

Thanks
 
Last edited:
Physics news on Phys.org
Look at articles on Quantum Gravity. In an Effective Field theory of gravity the mediating particles are gravitons which are spin 2 and massless.
 
cosmik debris said:
Look at articles on Quantum Gravity. In an Effective Field theory of gravity the mediating particles are gravitons which are spin 2 and massless.

Wow, now I found loads! At least I wasn't way off in my thoughts :) Thank you very much.
 
Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?

Similar threads

  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 36 ·
2
Replies
36
Views
8K
  • · Replies 10 ·
Replies
10
Views
5K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 31 ·
2
Replies
31
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 36 ·
2
Replies
36
Views
6K
Replies
1
Views
2K