Are Tachyons Relevant in Modern Physics?

[edpell]

Are Tachyons in or out of favor these days? I seem to recall going to a talk about Brookhaven data (RHIC) that invoked ladder diagrams with Tachyons in them. And no one in the room seemed to flinch. What up with that?

 

[pallidin]

Hmmm. Good question.

I would suppose that the entire problems lies within the scope of experimental validation.
Our scope is currently limited to c and sub-luminal observations/experiments.

Not sure how to get around this. Perhaps there is a way, but I don't know of one.

 

[blechman]

This is a very strange thing! Are you sure they said "tachyons"? Perhaps they said "Pomerons"? Do you have a reference to the talk?

The only other possibility I can think of is that they were trying to do some "Dual Model" calculation. But I don't understand how "tachyon exchange" makes any physical sense.

Tachyons are instabilities in the theory. Their presence signifies that you are in the wrong vacuum, and your calculations break down. This is what the "string theory tachyon" is, for example.

You can, of course, perform calculations of "tachyon exchange", but then you're just playing a mathematics game; your final answer will not have any physics in it!