James Fodor

speaker

3,084 appearances 4 recordings 1 series first heard Jun 2026 last heard 30 Aug

James Fodor’s voice in public audio — every appearance, attributed to the second.

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Recordings per month over the last 12 months — 4 in all, peaking in Aug 2026 with 2.

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The Science of Everything Podcast · Episode 164: Gauge Theory and the Higgs Boson · 30 Aug 2026 podcast

rid of that dependency by introducing this local phase invariance, or specifically by promoting the global phase invariance, which already existed to a local phase invariance, which is an extra requirement that we make, but then it turned out to cancel out the problematic terms and resolve the problem for us.

So the logic in QED electromagnetism was that interaction between electron and photon gives rise to local phase invariance.

But remember, for the weak nuclear force and the strong nuclear force, we didn't know what the Lagrangian should look like, including the interaction terms.

I mean we had an idea about what the kinetic terms and the mass terms should look like, because they're pretty standard, but we didn't know what the interaction terms should look like.

So we reverse the logic.

We said, well, let's impose a local gauge invariance to to the relevant fields, just like we did in electromagnetism, except with some differences which we're talking about.

So we'll we'll require this local gauge invariance, and that will then give us an interaction term.

And we'll assume that that interaction term is the correct one and we'll test experimentally.

So th there's no guarantee that this would work.

This was a methodological assumption, but it turned out to be successful in both cases.

Incre it's been incredibly successful.

Now, the the reason I think this is often poorly explained is because many, many lecture notes and even textbooks will say that requiring local gauge invariance in your Lagrangian, like generates or produces a gauge boson, which in the case of the strong nuclear force is your

Gluons, right?

Or the weakness of the voice to W and Z bosons.

Now I think that this is this is sort of mathematically true, but it's not really physically true.

Writing down an equation doesn't generate a physical field.

That doesn't make sense, despite the fact that you often see this language used.

Uh I think that we just have to understand they're speaking sort of mathematically.

When we require local gauge invariance, that means that there by necessity will be an extra field that we introduce into the mathematics that then couples to, or like interacts with, the initial fermion field.

Remember, we're always requiring the gauge invariance of the fermion field.

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