# Pilot wave theory

1. May 2, 2015

### asimov42

Hi all,

I've recently been reading a little bit about pilot wave theory (as a physics novice). It's an interesting interpretation of quantum mechanics, but I'm wondering (apologies that this is in very non-technical terms):

I can understand how the pilot wave interpretation leads to same results as 'standard' quantum mechanics for, e.g., the double slit experiment, where an ensemble of trials will show the expected interference pattern.

But isn't it also the case that a particle should with some probability spontaneously transition to form other particles (e.g., a photon spends some time as an electron-positron pair)? That is, as discussed at, e.g., http://www.scientificamerican.com/article/are-virtual-particles-rea/

From the above article, "quantum theory predicts that every particle spends some time as a combination of other particles in all possible ways."

Isn't this type of occurrence essentially random, and if so, how does the pilot wave interpretation deal with this?

Thanks.

J.

2. May 2, 2015

### Staff: Mentor

Its this virtual particle stuff.

Despite reputable sources like Scientific American saying things like that its wrong:
http://physics.stackexchange.com/questions/4349/are-w-z-bosons-virtual-or-not/22064#22064

They don't really exist - they are simply mathematical artefacts of the perturbation methods that is usually used to do the calculations. There are other ways of doing the calculations such as lattice field theory where they don't even appear.

Thanks
Bill

3. May 3, 2015

### atyy

As bhobba says, the virtual particles are an approximation used in quantum field theory. At least for QED, one can make a lattice theory which gives all the same predictions, eg. http://arxiv.org/abs/hep-lat/0211036. Because a lattice theory with small but finite spacing in finite volume is just ordinary quantum mechanics, the pilot wave theory is probably able to deal with it, eg. http://arxiv.org/abs/quant-ph/0611032.

4. May 3, 2015

### asimov42

Thanks Bill, atyy,

So then can one consider a real particle, say an electron, as always 'being' an electron? (assuming it's not annihilated by a positron at some point) That is, if we consider an electron moving in free space, will it never undergo a spontaneous change to another particle pair and back? I guess I"m asking if the statement from Scientific American that "quantum theory predicts that every particle spends some time as a combination of other particles in all possible ways" incorrect?

J.

5. May 3, 2015

### Staff: Mentor

Yes. An electron always remains an electron.

Thanks
Bill