Recent content by pervect

I ran across the very interesting https://arxiv.org/abs/quant-ph/0302081, "Geometry of the 3-Qubit State, Entanglement and Division Algebras" which goes a long way to answering my own question. The extra phase factor is not eliminated

In my opinion arguments over or about the one way speed of light are pretty much a dead end, but rereading the post I see Peter was right in commenting that this was the original question. Somehow I thought the OP was interested in whether the radial speed of light was the same as the...

Is clock syncrhronization actually important to your question? It's not obvious to me why it's relevant to your problem, and it'd be a lot easier to analyze the problem if you could get rid of it. I'd suggest about thinking why you need it, and the approach I'd take to that is to try and...

Because to OP is talking about "reference frames", they are most likely doing Newtonian physics and not actually doing GR. If they were doing GR, they would be talking about what metric they were using rather than about "reference frames". But I'll try to answer the question both from a...

Consider the Euclidean metric of a plane, dx^2 + dy^2 = 0. Formally, this would actually be called a line element, mea culpa. Any linear transformation of this metric, which we can perform algebraically or by other means (such a the tensor tranformation rules) provides an equivalent metric...

In https://web.cecs.pdx.edu/~mperkows/june2007/bloch-sphere.pdf, Ian Glendinning describes a derivation of the Bloch sphere for one qubit. To paraphrase his basic argument, one qubit in a pure state can be represented by 2 complex numbers, ##\alpha= a + bi## and ##\beta = c + di##. This yields...

Can you really read the formulae and the diagrams on the Kindle version? I would think it'd be tough to get much out of it :(.

I would say that your characterization of GR as saying that "the planet is stretching" is flawed. But lets move on to your question, perhaps the answer to that will help clear up your confusion and lead you twoards a less-flawed understanding of what GR is saying. The closest approximation...

A recap of what others said. If one defines coordinates on a manifold, (to be more formal, one might talk about a coordinat chart), one automatically define a coordinate basis. But, that's not the only possible basis one might use. Frequently, one is interested in some other basis, such as an...

When talking about directions, I've had arguments in the past about whether a "spacelike" direction is a vector, like ##\partial / \partial x##, or a dual vector, like dx. This doesn't make much difference in a true orthonormal basis, but it does in other cases and can cause arguments. The...

I can quote some of the equations you need for a Schwarzschild black hole, I don't know how good an approximation that is for Sag A*. From "Oribits in Strongly Curved Space-time", https://www.fourmilab.ch/gravitation/orbits/, which is the same eqautions as MTW's textbook "Gravitation" we have...

Thanks - I did find the thread interesting. The previous papers had too much distracting wordage on things I found irrelevant, like Mach's principle for my taste. Your summary seems a lot more intelligible with much more focus. Or perhaps it was just that it was simple enough for me to...

Thanks for the links. I'm not too impressed by the approach itself at this point if the papers are representative of it, but that's a separate matter. It's also based on a very quick reading.

Some popular news articles mention https://academic.oup.com/mnrasl/article/537/1/L55/7926647?login=false, "Supernovae evidence for foundational change to cosmological models" as suggesting that "Timescape" cosmological models may be superior to the Lambda-CDM model. My question relates to what...

Pick your favorite textbook (I like MTW's text Gravitation) and follow along for the textbook's conventions (which are usually pretty standard, though they can vary a bit) about how to say things. I don't think I've ever seen a formal textbook talk about a component "along a direction" - so I...