rantonels

Furey uses O multiplication rules to show how the Clifford algebra Cl(6,C) arises

she actually doesn't. The octonions are non-associative, but she defines an alternate associative version of CxO acting on itself. Hence why you get the (much more mundane) associative Clifford algebra. That in my book means taking the octonions and removing the entire octonionness and using essentially R⁸

Instead of getting upset about work you haven’t thoroughly read, why don’t you focus your energy on something positive? Why don’t you start writing some disruptive papers yourself? Have you ever stuck your neck out for an idea?

I have a paper in review with a couple of friends that I think puts forth a fairly bold proposal. You can read it if you want.

do you understand how all this gives you non-unitary time evolution?

You don't need to id every particle in the universe, a probabilistic curve is enough (which is what physics shows us is, funny enough).

That's only in the thermodynamic limit. Probing such a probabilistic simulation in a non-thermodynamic regime is going to reveal measurable inconsistencies.

A black hole can be perfectly simulated with just a few variables: location, spin, mass, charge. The black hole can be simulated from just that information.

That's only in the classical limit, which for quantum gravity is the thermodynamic limit. Again, I can experimentally measure an inconsistency in principle if I observe the Hawking radiation from the BH.

If you want to simulate a BH from the quantum-gravitational standpoint you need to also consider its microscopic evolution that the macroscopic picture misses. The amount of missed information, which is extremely large and in fact maximal, is precisely the Bekenstein-Hawking entropy.

So correct your statement about black holes being the heaviest cost on computer resources.

No

The human brain is the most uncompressible object we know of. This means more resources will go towards simulating a human than towards simulating an entire galaxy.

That's insane. Also considering I recall there being evidence of a galaxy containing human brains.

In fact, one hypothesis states that the reason we don't see intelligent life out there is because if we did, the memory requirements of the simulation would exceed its capacity and we'd glitch out of existence. This implies we can cause this glitch if we keep adding to informational complexity.

Wow. And this is somehow more reasonable as an hypothesis than there not being any intelligent aliens near us?

This same principle is why a Boltzmann brain is virtually impossible compared to a big bang brain; 10⁸⁰ particles will always form a big bang whereas 10²² particles will never form a brain.

I don't really understand what you're trying to say here, I think there's more implicit jumps than I can follow.

My ultimate interest is in understanding the microscopics of spinning black holes in quantum gravity. But a clear reconstruction of the microscopics is generally only possible with supersymmetry; in addition supersymmetry and rotation of black holes can only coexist in dimension greater than four. Therefore if one steps to higher dimensions, from studying these supersymmetric rotating BHs there is hope of being able to isolate at least qualitatively how spin works in general, in particular also for the normal four-dimensional Kerr black holes.

This one in six D is an odd-ball. It's a step away from supersymmetry and I would consider that promising, especially if (as I hope) I can match it to an equivalent description in string theory in terms of branes.

That's... Bizarre. Is it rotationally extremal?

No, doesn't need to be. Actually if you look at truly susy black rings in 5D the susy implies charge extremality but not spin extremality.

Also, in what sense do you mean the NH is BPS? The AdS2 S2 NH geometry of 4d Kerr admits a killing spinor (I think),

NH of extremal Kerr has a squashed AdS3 factor and it's not susy, AdS2×S2 is the NH of extremal RN which has a killie spinnie

but I'm not sure I'd say that extremal KN has a BPS NH geometry...

It doesn't indeed, in 4D susy => non-spinning. In 5d you can have susy spinning BHs, both spherical (NH AdS2×S3) and rings (NH AdS3/Z×S2).

But in 6D you cannot have any globally susy BH at all. In addition the NH of a would-be spherical susy BH, which is AdS2×S4, cannot be susy.

Anyway the NH of this ring is that of the self-dual string of 6D sugra, which is AdS3/Z × S3, and the BPS bound relates the string tension (or ADM mass per length if you want) with self-dual 3-form flux. It's precisely the smaller brother of the type IIB D3.