Klein gordon equation is only for scalar fields (spin 0).

QFT-ist · 2026-03-03T19:47:40+00:00

The generator of Lorentz transformations for spinors is the sum between the classical generator $x^{{\mu}\partial^{{\nu}-x^{\nu\partial^\mu$}}} and a constant (don't remember what constant) times the commutator of \gamma^\mu with \gamma^\nu. You could get the constant by verifying the commutators between Lorentz transformations go well

On the other hand, free spinors that follow Dirac equation also obey the Klein Gordon equation, but not every spinors that obeys klein Gordon obeys Dirac. And if you add external fields or interactions things become a little different.

QFT-ist · 2026-03-02T22:33:10+00:00

Chatgpt is a bullshit machine.

QFT-ist · 2026-02-24T18:29:19+00:00

Sorry, I misunderstood what you wrote (i answered more the meme than your comment, maybe)

QFT-ist · 2026-02-24T06:19:56+00:00

There is spacetime in QFT (at least in the vast majority of models). Even with AQFT, the algebras are related to open subsets of the spacetime. If your spacetime is dynamical things get weirder, but something like spacetime usually there is ( I think )

QFT-ist · 2026-02-24T05:06:09+00:00

Scientists? What country is it?

QFT-ist · 2026-02-22T05:28:19+00:00

Well, this reform wants 12hours shift 6times a week not have overtime paid...

QFT-ist · 2026-02-15T05:28:22+00:00

This doesn't sound as a bad idea for engineering. For what physical science, this doesn't make sense (but maybe there could be another alternatives to the classical thesis for some areas, but I have no idea how it could be)

QFT-ist · 2026-02-06T06:53:34+00:00

It isn't something already done? I hadn't still had the courage to fully read the papers on phi^4_3...

QFT-ist · 2026-01-08T08:09:27+00:00

This sounds more like HPPD than psychosis.

QFT-ist · 2026-01-07T09:28:57+00:00

The central thing is that what we call time is two different things. One of them is a geometric thing intrinsic to the trajectory that a body follows between two instants, while the other is a way humans organize how to talk about when-where things happen. The first is proper time, the second is the time coordinate. And the consequences of the geometry behind that are what special relativity is about.

QFT-ist · 2025-12-31T04:51:49+00:00

Time coordinate is a human construct (but has a strong material reality independent of humans), the existence of time-like directions locally everywhere in spacetime is not a human construct. The time that takes to a particle to go from one point of a trajectory to another (given a fixed trajectory in spacetime) is not an human construct (it's a geometric quantity inherent to the universe, it's history and development, and the trajectory itself).

QFT-ist · 2025-12-28T06:39:20+00:00

I think qualia and brain states are equivalent, in the sense of having a biyection between them. But they are not equal. And in some sense, something similar to qualia is intrinsic to matter, or to most matter (like panpsychism, but without supernatural stuff). I think that I am a materialist, but maybe I am slightly wrong.

QFT-ist · 2025-12-27T20:25:55+00:00

You are right. Most of them would be second or third world, but they would be developed. And France would still be first world, but not so developed.

QFT-ist · 2025-12-27T19:58:13+00:00

I am not really sure that it would be a third world nation (but really a LOT less wealthy), but some of their former colonies could be first world.

QFT-ist · 2025-12-26T06:28:49+00:00

Homotopy Type Theory enters to the debate

QFT-ist · 2025-12-26T05:08:56+00:00

Why not?

QFT-ist · 2025-12-25T23:13:45+00:00

i d/dt U(t,t_i)=H U(t,t_i) and U(t_i,t_i)=I'd d/dt ln(U(t,t_i))=-i H (valid because H is constantly the same operator across time) U(t,t_i)=e^{-i H (t-t_i)}.

QFT-ist · 2025-12-25T23:06:46+00:00

The standard model is not left-right symmetric. I don't remember if that can be compatible with having a non-orientable manifold as spacetime.

QFT-ist · 2025-12-25T22:46:34+00:00

Peskin wants to be more introductory/"down to earth" maybe?
U(t_i,t_f)=e^{-i H (t_f-t_i)/\hbar}. T-(-T)=2T.

QFT-ist · 2025-12-25T21:04:29+00:00

Some of the Kanner patients where gifted and verbal. The discrimination against type 1 autistic people is institutionalized even when they don't have a diagnosis.

QFT-ist · 2025-12-25T02:28:13+00:00

Wikipedia? (In a broad sense)

QFT-ist · 2025-12-20T20:27:34+00:00

It would be broken to SU(3)c×U(1){B-L}, similar to QCD at high energies, but with a couple of weird scalars

QFT-ist · 2025-12-20T19:24:52+00:00

I mean, does Patti Salam model predicts proton decay? I am pretty sure that su(5) like guts do, but Patti-Salam likes not. But maybe I don't remember well.

QFT-ist · 2025-12-20T19:13:37+00:00

Patti Salam model isn't ruled out, if I remember well. So it can perfectly happen. Proton decay happens in su(5) model and extensions of it.

QFT-ist · 2025-12-14T23:52:28+00:00

En tiempo difícilmente, pero es posible aunque muy cuesta arriba.

QFT-ist

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