Recent content by mitchell porter

It turns out that the 500-page paper had a forerunner in 2000 that's just 100 pages, so it might be easier to read. :-) "de Sitter Space as a Glauber-Sudarshan State" (Brahma, Dasgupta, Tatar) This paper starts with a review of the De Sitter debate in quantum gravity and string theory. The...

An anonymous string theorist ("Stringmaster") showed up at Peter Woit's blog to state an abbreviated version of what they think this century's progress in string theory has been about: https://www.math.columbia.edu/~woit/wordpress/?p=15348#comment-252759 To me, the prose looks like it's been...

Do you remember what prompt you used to generate that image? Gizmodo recently ran an article asking "whatever happened to string theory?" My comment: "In general, the biggest thing that happened is that nothing but the Higgs boson showed up at the LHC. This all but falsified what had been...

I don't know about Manin, but complex gauge theory has seen use in pure math, e.g. in the Hitchin fibration (also known as the theory of Higgs bundles). But that's just the classical theory (and in 2D). Regarding the quantum theory: No, that's all still true. There are a handful of cases...

I thought of posting this under Particle Physics, but it does go slightly beyond standard model, and in a way that could point to some larger theories, so I post it here. "A path to confine gluons and fermions through complex gauge theory" (Amaral et al 2020) "New picture on the mesons mass...

Just to be clear, I claimed the problem was that chiral gravi-GUTs want to use SU(2)R as the gravitational gauge group, but in Pati-Salam you also need it to supply part of U(1)Y, the hypercharge gauge group in the standard model. Alexander et al's approach is to abandon that part of Pati-Salam...

I think the summary in Sabine Hossenfelder's new video is excellent. Many important points made, I have bolded two at the end that interest me the most: "The Nobel Prize winning observation heavily relied on regularities of [Type 1a] supernovae. They assumed that these stellar explosions...

Formally you could do it but that's not really a gravi-GUT any more, or at least the gravitational SU(2)R is no longer united with the observed forces. You just have SO(10)_1 x SO(10)_2, the first SO(10)_1 is a standard SO(10) GUT whose breaking passes through standard Pati-Salam, and then the...

If you're asking about vacuum selection, no one's even thinking about it. The focus in string phenomenology is still just to find vacua that look like reality, and to improve the ability to calculate their properties. Anthropic selection is the only selection principle that even gets mentioned...

I do not see anything in their argument that actually relies on the topic being quantum gravity. They could have written a paper, "Consequences of Undecidability for the Theory of Packing a Lunchbox", with the exact same structure.

The standard model gauge group is SU(3) x SU(2)L x U(1)Y. Before the Higgs mechanism comes into play, the latter two subgroups give rise to four massless bosons that Weinberg dubbed W1, W2, W3, B. After the Higgs field gets a VEV, W1 and W2 becomes the massive W+ and W- bosons known to...

Gravi-GUT theories turn out to play a major role in the alternative physics of the past several decades. E8 theory by Garrett Lisi (@garrett) is a gravi-GUT theory. So too, it turns out, is Eric Weinstein's Geometric Unity, by a slightly roundabout route (in GU, our 4-dimensional world is a...

That's not the problem, the problem is that the existence of negative energy particles allows endless materialization without violation of conservation of energy, so long as they materialize paired with positive energy particles so that there's no net change of energy. Have you thought about...

I report two paper which provide examples of ingredients one might expect in a field-theoretic treatment of the sbootstrap. "Color gauge invariant theory of diquark interactions" (Wang, Zhang, Sun) "A - BCD dualities" (Amariti, Mantegazza, Rota, Zanetti) In QCD, we could say that the basic...

The problem with negative energy is not just "blasphemy", it is that you can have endless creation of something from nothing. You can go from a situation of net zero energy, to one with a positive energy particle and a negative energy particle whose energies sum to zero, or an arbitrary number...