KnightWhoSaysNi

I'd like to ask for some input from the physics buffs here. I've read an interesting book called Beyond Star Trek by Lawrence Krauss. In the book, Krauss refers to Richard Feynman's work regarding quantum vacuum fluctuations, where 2 particles (a proton and anti-proton) appear out of nothing and annihilate each other.

According to Feynman (through Krauss), this is what happens (pp.126-127):

Krauss goes on to say that the FTL backward-in-time proton has a negative electric charge (antiproton) and annihilates itself with a forward-in-time proton, leaving just one proton from the three.

Is Feynman pretty much on the money here? If so, this is really quite fascinating. In that case, tachyons (faster than light particles) are not mere science fiction anymore. Is antimatter essentially stuff that's going backward in time?

tronvillain

Uh, that quote does not appear to have anything to do with quantum vaccuum fluctations.

Philosoft

And tachyons are negative mass particles in addition to FTL.

ohwilleke

I think that the notion that some particles move backwards in time with a change in property makes a lot of sense. And, certainly Tachyons (faster than light particles by the definition I'm used to), a relevant to this notion.

I imagine that the oblique reference to vacuum fluxuations here is the notion that a single particle could give rise to three particles, two of which then disappear again, seemingly out of nothing, by moving forward and then backward in time.

tronvillain

Nightshade:

I must say that it sounds extremely unlikely. After all, it is the same proton three different times - if the backward-in-time proton annihilates the pre-backward-in-time proton or the post-backward-in-time proton the earlier the earlier proton will not be around to become the later proton to permit the annihilation.

Answerer

If tachyons do exist, our dear physicists and philosophers will have to rethink their law of causality again.
Anyway, guys, if I remember correctly, Casmir effect state that zero-point energy of the vaccum state has a value of infinite, but how is this possible?

Friar Bellows

Really? I thought they had imaginary mass (by imaginary I mean like the square root of negative one). But I could be wrong. I'm shockingly ignorant of physics created after 1930.

Demosthenes

You're talking about a vaccuum diagram.

Two particles, proton and antiproton appear out of nonwhere move forward in time and then merge to disappear. According to the diagram what happened was that the moment of collision created a particle which moves backward in time to initiate the creation of the proton and antiproton particles.

And yes, Friar Bellows, tachyons have imaginary mass not just negative mass.

Friar Bellows

Aren't they also called Feynman diagrams? That Feynman dude was one smart cookie.

Answerer

Are you trying to say that the creation of the proton and anti-proton is a cyclic process?
Anyway, what was the particle that moved backwards in time?