GRQFT's latest activity

I'm interested in learning enough to understand relativity (and QFT). I studied physics in college (decades ago), so I guess I'm at a...

Okay, thanks. There's clearly a lot that I need to learn about tensors! I was thinking of buying a copy of Sean Carroll's Spacetime...

Yes, which in tensor notation in D-dimensions, just means to fully contract any given rank-k tensor with the D-dimensional Levi-Civita...

When you say "...that's dual to ##c_{k}##", are you talking about the Hodge dual?

Yes, both tensors contain the same information (6 independent components) since one is just a rearrangment of the other. It's exactly...

My guess is that subsurface regolith dust is lighter in colour than surface dust - that regolith exposed to the elements for millions of...

I assume the middle part where you have that back and white contrast is the crash site and possibly displaced dust and rock. There...

Looking at what you wrote above makes me think that the notion that the magnetic field is really just an electric field viewed in the...

So, I'm guessing the black circle in the center of the photo on the RHS is the impact crater. But what's all that bright white stuff...

Thanks so much for taking the time to write all that out! So, to make sure I understand, you're saying that because Maxwells equations...

Yes. The RHS of the wave function contains a 2nd derivative for ##ct##. In SR, ##t## is multiplied with ##c## as conversion factor. You...

Derivation of the EM wave function (a linear, second-order partial differential equation) from Maxwells equations in (3+1) notation...

Are you sure this isn't a recording of one of his lectures or an interview?

That 1) and 2) are equivalent can be seen in Gaussian CGS units. Maxwells equations contain partial derivatives for ##ct## of the...

In 4D-spacetime ##(ct, x, y, z)##, the EM field is a bivector. It has 6 components (3 electric + 3 magnetic), which are projections on...