If bosons don't interact, then how can gravity affect the path of light?

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Discussion Overview

The discussion revolves around the interaction of bosons, specifically in the context of gravity's effect on the path of light. Participants explore theoretical implications of boson interactions, the nature of gravitational fields, and the relationship between photons and gravitons. The scope includes conceptual clarification and technical reasoning related to quantum field theory and gravitational effects.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that while bosons do not interact in the same way as fermions, the presence of a gravitational field (and thus gravitons) influences the probability of photon appearances, implying a form of interaction.
  • Another participant questions the assertion that bosons do not interact, seeking clarification on who makes this claim.
  • A different viewpoint notes that bosons do not obey the Pauli exclusion principle, contrasting them with fermions, which repel each other even without many-body interactions.
  • One participant emphasizes the need for the original poster (OP) to clarify their statement rather than making assumptions about their intent.
  • There is a suggestion that the bending of space due to mass-energy could be viewed as an interaction between photons and gravitons, with a request for a Feynman diagram to illustrate this concept.
  • A participant provides a mathematical expression related to the electromagnetic Lagrangian, indicating how to derive a vertex that couples two photon lines and a graviton.
  • One participant acknowledges a misunderstanding regarding the nature of non-interacting bosons after a challenge from another participant, expressing gratitude for the clarification.
  • A later post humorously acknowledges the participant's earlier mistake and their test score, indicating a light-hearted tone in the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the nature of boson interactions and the implications of gravitational effects on light. There is no consensus on the initial claim regarding bosons, and the discussion remains unresolved regarding the specifics of these interactions.

Contextual Notes

Some statements rely on assumptions about the nature of bosons and their interactions, which may not be universally accepted. The discussion also touches on complex theoretical concepts that may not be fully resolved within the thread.

nomadreid
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One says that bosons do not interact with one another. However, the presence of a gravitational field, and hence of gravitons (bosons) (assuming they exist), changes the probability of where a photon (boson) appears, which is the same sort of interaction as two fermions, no?
And, the contrary: mass-energy tells space how to bend, and this bending of space is essentially the gravitational field, so isn't this an interaction of photons and gravitons?
 
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"One says that bosons do not interact with one another."

Who says?
 
Perhaps what one means is that bosons do not obey the Pauli exclusion principle.

This needs to be compared with fermions: Even non-interacting (i.e. no many-body interactions) fermions repel each other due to the Pauli exclusion principle. Bosons on the other hand do not repel in case of no many-body interactions.
 
Let's not guess what the OP means; let him explain it himself.
 
mass-energy tells space how to bend, and this bending of space is essentially the gravitational field, so isn't this an interaction of photons and gravitons?
I think there should be a feynman diagram for it?
 
I think there should be a feynman diagram for it?
Sure. One choice for the electromagnetic Lagrangian is

L = - ½ Aμ,νAμ,ν = - ½gμσgντAσ,τAμ,ν = - ½(ημσ + hμσ)(ηντ + hμσ)Aσ,τAμ,ν

from which one can pick out the vertex that couples two photon lines and a graviton.
 
Oops, my apologies to all who responded; I misread an article ( "The Computational Complexity of Linear Optics", by Scott Aaronson and Alex Arkhipov), which outlines experiments using non-interacting bosons -- and I misread the way this phrase to mean that all bosons were like that. But after the challenge by Meir Achuz, I re-read it and understood my mistake. My thanks to Meir Achuz (like mea achuz~100%?), Regel, Vanadium 50, adrien, and Bill K.
:blushing:
 
nomadreid said:
My thanks to Meir Achuz (like mea achuz~100%?)
You have outed me. Now you know my test score, and my safah.
 

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