Is the Concept of a Positron Traveling Backwards in Time Still Accepted in QED?

[QueenFisher]

i read QED the other day, and was wondering, is the idea that a positron is an electron traveling backwards in time still generally accepted?? cos i know he gave the lectures a while back, and lots of things have changed since then, but it stuck me as an interesting concept.




p.s. i may have put this in the wrong forum again. sorry if i did.

 

[Astronuc]

Yes, this is the right forum.

Apparently the concept of an anti-particle moving backward in time is still taught in the context of Feynman diagrams.

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/expar.html#c2

 

[QueenFisher]

is it only in the context of Feynamn diagrams? is it because they use space and time? or can you use it in the 'real' world as well?

 

[Astronuc]

I suspect that it is the use of Space-Time or Minkowski space. I would defer to a physicist as to relevancy in the 'real' world, however it does appear to have application in 'real' world problems.

Here is some background - http://en.wikipedia.org/wiki/Space-time
http://en.wikipedia.org/wiki/Minkowski_space

 

[Physics Monkey]

Hi guys,

The statement that particles traveling backwards in time correspond to antiparticles traveling forwards in time is a valid one. In fact, some of the greats, like Feynman, preferred the evocative language of electrons moving forward and backward in time, but mostly now days people prefer to talk about electrons and positrons all moving forward in time. The two are equivalent, however.

 

[Astronuc]

It's definitely not a concept I use everyday as an engineer, and I have been away from academia for awhile, so I am not familiar with what is being taught in the advanced physics courses.

Thanks, Physics Monkey!

 

[dextercioby]

QED is not only CPT invariant, but also CT invariant. This means that scattering experiments (for example) are identical if time "flew" backwards and all electrons became positrons at the same time.

Daniel.