Does Light Bend Spacetime and Have a Gravitational Pull?

[Tomtom]

E=mc^2. Mass warps spacetime. From use of the aforementioned equation, light can have a hypothetical mass (can't it?). So, does light bend spacetime, and consequently, bend light?

Does light have a gravitational pull is another way of phrasing my question.

 

[ZapperZ]

Have you read our FAQ yet in the General Physics forum? If you haven't, that might be a good place to start.

https://www.physicsforums.com/showthread.php?t=104715

Zz.

 

[Tomtom]

That was a good read! Thanks a lot. However, it still doesn't answer my question ;)

I guess what I am looking for, is serious discussion on the subject, or any papers written on it. I've searched a bit, but only found forum discussions with too many "I think"s.

I've just found two threads on this forum concerning the topic, but there are no clear answers.

 

[George Jones]

I've just found two threads on this forum concerning the topic, but there are no clear answers.

From page 427 of Quantum Field Theory in a Nutshell by A. Zee:

An interesting question: Einstein said that light is deflected by a massive object, but is light deflected gravitationally by light? Tolman, Ehrenfest, and Podolsky discovered that in the weak field limit two light beams moving in the same direction do not interact gravitationally, but two light beams moving in opposite directions do.

Zee then uses quantum field theory to show this, but I'm sure that Tolman, Ehrenfest, and Podolsky used only classical relativity to deduce the result.

 

[Tomtom]

George Jones: Thanks you very much! It's not often I get an affirmative on a theory here ;) Is there more info on exactly that in your book? I've considered buying that one myself.

 

[MeJennifer]

This paper might be of interest to you: http://arxiv.org/abs/gr-qc/9811052v1

 

[Tomtom]

Very interesting MeJennifer! Great to find that there exists understandable research on the subject! My mathematics (and physics) are only slightly above A-level-equivalent, so I didn't understand most of the math, but the conclusion was "readable". =)

 

[MeJennifer]

Even in special relativity one can make some inferences about the directions of two photons. For instance a system of two photons moving in the same direction has no rest mass while a system of two photons moving in opposite directions has a rest mass.

 

[coelho]

Even in special relativity one can make some inferences about the directions of two photons. For instance a system of two photons moving in the same direction has no rest mass while a system of two photons moving in opposite directions has a rest mass.

Is it because we could define a "center of mass" of the systems of two photons, and in the case of the photons moving in opposite directions this center of mass would be moving at v<c (what allows a rest mass), while in the case of the photons moving in the same direction the center of mass would moving at v=c, what doesn't allow a rest mass?

 

[Antenna Guy]

Is it because we could define a "center of mass" of the systems of two photons, and in the case of the photons moving in opposite directions this center of mass would be moving at v<c (what allows a rest mass)

By the same token, what does the velocity of a phase center say about the rest mass of a spherical wave?

(n.b. In antenna terms - "phase center" is where r=0 in e^{-jkr})

Regards,

Bill