PeterDonis's latest activity

And linear algebra as well.

To clarify a point that might be confusing here, in the light of what I said in post #8 earlier in this thread: if I have a single...

You still don't appear to grasp that "an individual physical system" in QM is not the same thing as an individual elementary particle...

Yes. Nobody is disputing that. But, as I've already pointed out, this fact has nothing to do with ensemble interpretations vs...

Yes, I get that, but it seems to me that there is a fundamental tension between using that as the definition of "the road" and trying to...

Ah, I see; I had gotten mixed up between your "orthogonal to foliation" notion of distance and your "odometer" notion of distance. Of...

In other words, you now agree that "##c## times the time the photon has traveled" has no physical meaning in an expanding universe?

But by that definition of "distance", the observer at the center of the bubble covers a nonzero distance: ##v_s t##, don't they? I'm...

We've already computed it in the regular warp coordinates: it's just Euclidean distance in the surfaces of constant coordinate time...

But you said exactly this in your last post, just above!

Okay. Then what do you think "##c## times the time the photon has traveled" means, physically? You must think it means something...

Yes, and such an observer is at constant ##\xi##, so this in itself does not argue against ##\xi## being the "odometer distance"...

Once again: as far as we can tell, there is no ground in any reference you've given for your interpretation of this quantity as "the...

I've read Misner, Thorne, & Wheeler in full, more than once, as well. Which took, um, quite a bit longer than it took to read...

These are the same. Yes, agreed. On any foliation slice (all of which are orthogonal to the bubble center), the bubble only occupies a...