Recent content by strangerep

I've only been referring to DG at a rather basic level. The first few chapters of Carroll's "Spacetime and Geometry..." should be enough -- if studied properly. If you can master that, a more advanced presentation can be found in Matthias Blau's Lecture Notes on General Relativity. (Personally...

Yes, and the torsion is only relevant inside matter.

@ric peregrino : It sounds like you're not yet aware of Einstein's "Non-symmetric Unified Field Theory". (Google will yield plenty of references.) I did a bit of work on it in the late 1970's, but remain angry to this day that my supervisor guided me to participate in this deadend research that...

It appears to have been published 20-Jun-2024 (open access).

Er,... which "three groups" are you referring to?

This is no longer a "question mark" for anyone who has actually studied and understood the most recent papers that use several different statistical analysis methods. This new version (v3) from Chae performs yet a 3rd type of analysis, different from the earlier "acceleration-plane" and "stacked...

Short answer: "no". For a longer answer, read up on the distinction between "intrinsic" and "extrinsic" properties.

Well, I await a well-founded justification of your assertion. (It seems to me to be speculative wishful thinking, but I'm willing to be convinced otherwise, if the math holds up.)

Here is my "proof" (from the private conversation mentioned by @renormalize), that if ##A## is hermitian, then ##B## cannot have definite hermiticity... Suppose ##A^\dagger = A##. Then, $$B ~=~ [A,B]~, ~~~\Rightarrow~~ B^\dagger ~=~ [B^\dagger, A^\dagger] ~=~ [B^\dagger, A] ~=~ -[A,B^\dagger]...

@physicsxanime : where did this exercise come from? Please post a link or reference.

Which folks? Which theories? (And you think galaxy dynamics in the plane of the spiral is "easy"??)

Did you? Are you sure you haven't forgotten some stuff? :oldwink:

Is there CCTV? Can the student protestors be identified reliably?

I did watch the whole video. I think Vanadium's assessment is fair, perhaps even too mild. I also watched the previous video she refers to. My impression is that, (like Dr Becky, for example), these astrophysics youtubers do not bother to study the MOND-related literature properly, e.g., recent...

These are not the only possibilities. To see why, decompose A into hermitian and skew-hermitian parts, i.e., $$\mbox{Let}~~ A ~=~ X + Y ~,~~~ \mbox{where}~~ X^\dagger = X ~,~~~ \mbox{and}~~ Y^\dagger = -Y ~.$$(Do you know how to prove that A can always be decomposed like this?) With this...