Okay, so this is another attempt to unify quantum field theory and gravity. By using gravity to get quantum fields, rather than by trying to quantize gravity.
If the paper is attempting to express electromagnetism in terms of the metric tensor, then it is putting it into a form that makes it potentially compatible with gravity, which is also a metric tensor. Quantum theories use a completely different type of math, and trying to express gravity in that way (quantizing gravity) results in a bunch of broken equations. If both systems can be described using differential geometry, that is a step in the direction of unifying the theories, even if it's not a hole-in-one.
> If the paper is attempting to express electromagnetism in terms of the metric tensor, then it is putting it into a form that makes it potentially compatible with gravity, which is also a metric tensor.
But the metric tensor of spacetime, in General Relativity, which is our best current classical theory of gravity, only explains gravity. Gravity, by itself, uses up all of the degrees of freedom in the metric tensor. There aren't any left for electromagnetism or anything else.
To get classical electromagnetism, you need to add another, different tensor to your model--a stress-energy tensor with the appropriate properties to describe an electromagnetic field. Of course doing this in standard GR is straightforward and is discussed in GR textbooks; but it does not involve somehow extracting electromagnetism from the metric tensor. It involves describing electromagnetism with the stress-energy tensor, i.e., with different degrees of freedom from the ones that describe gravity.(And if you want to describe the sources of the field, you need to add even more degrees of freedom to the stress-energy tensor to describe charged matter.)
The paper does not, as far as I can see, address this issue; the authors don't even appear to be aware that it is an issue. Which makes me extremely skeptical of the paper's entire approach.
I'm not surprised by this divestiture - Investor confidence in Alterra has been low ever since the disastrous loss of their brand new capital ship Aurora on its very first mission.
Anything that can be copied infinitely for free has a market value of 0, and is in a bubble whenever its price is above 0. This doesn't mean that video games have no value, but that markets aren't suited for finding it.
I won't deny that genAI is still a long way from passing the strictest scrutiny, but I don't like the above argument. Ease of use is not a trivial matter, and extreme advances in accessibility can cause a phase-change. Photo evidence continues to be useful because editing photos is below the critical threshold for becoming a problem. If it becomes easy, low-skill, and reliable, at that point we will cross into the realm of Reasonable Doubt. It's the difference between possible, and practical, and pervasive.
FWIW, given everything else that we've seen from Russia in this undeclared(!) war, I'm moderately confident the Russian nukes and delivery mechanisms are sub-par.
(Typing "sub" reminded me of the Kursk nuclear submarine that sank itself…)
It needs only a few to launch successfully to engulf Europe in flames.
So, even with subpar equipment, out of all of the 1700+ launch vehicles a few will still launch.
Some of the P(weapon failure) is constant: from what I hear, a certain fraction of Soviet and US systems (and presumably everyone else's) just don't work.
If that was all it was, then you would be correct.
But: some failures come with age, and require ongoing maintenance to retain function. For example, I expect all the tritium has decayed, and also that in many cases the money that was supposed to get spent replacing the tritium was instead spent on a fancy yacht or a football team or a seat in the UK's House of Lords etc.
And I don't know how good modern anti-missile weapons are, but I would expect them to have improved; conversely, despite Russia's talk about new hypersonic missiles, what they've shown hasn't been very impressive, and they've even used up some of their old nuclear-capable missiles while attacking Ukraine.
I'm happy to be relaxed about this, but only because I have no power — 90% chance some attempted hot war is actually all duds is great for me personally, 10% chance everything burns is unacceptably high for someone running a country.
Russia and China are regional powers and can't project military power very far, excluding nukes. To do that you need a credible blue water navy. China is close though, and definitely projecting its economic strength.
Europe (lets just say EU + UK) could be a superpower. However they lack political unity. And still want big daddy US to do the heavy lifting.
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