Is a representative of a conformal metric just basically any normalized metric tensor by some scalar dependent on the metric

I think I've seen $$\frac{g_{\mu\nu}}{g_{00}},\ \frac{g_{\mu\nu}}{\det{g}}$$

so far

Now even sparrows are my enemies

Not anymore

All the length scales in physics seem to involve (in addition to mass) either some interaction or QM

I think it may be related to all that nonsense Coleman says about acceleration fields

I think geodesic ones don't really determine any length scale

@Feynman_00 ...what did the sparrows do to you?

> We shall see that in the Weyl space-time the proper-time interval and the particles masses are of nonzero Weyl weights, and hence they vary under Weyl gauge transformations. Such quantities are not of much significance in the Weyl space-time.

Looks like the whole length scale is connected to that Weyl potential thing

The stress energy tensor associated to the Weyl potential seems to be the trace of the usual SET

Is that mass related?

I am guessing it is connected to the whole "conformal invariance means zero trace"

@ACuriousMind is singing from 5.30 am to 6 am a good reason to be included in my bird deathnote? :P

tbh they are too cute. I find myself defeated once again

heh

birdsong doesn't really bother me - I think living next to a tram line for a few years has desensitized me against waking up from sounds :P

I guess part of the connection of the Weyl vector to the mass is that since it's a non-metricity tensor, you have $$\nabla_p g(p,p) = \omega(p) g(p,p)$$

So you have that the mass varies as ~ $\omega(p)$

hence why you need the Weyl vector to vanish to have a good spacetime structure

Also assuming that the conformal derivative only affects the volume structure and not the conformal one, I'm pretty sure that means something like $\nabla \det(g) = d \det(g) = \omega$

GR was so good they made a GR II

GR II: Quantum Boogaloo?

I don't know, sequels tend to be disappointing :P

just wait for the GR cinematic universe

I don't want to live in that world

Actually I've never watched a movie of the MCU :P

Maybe Iron Man I when I was a child

not the worst life decision :P

By any chance, ACM are you a German detector?

I mean...I am German

in that case the "train station" is a literal translation of a German idiom

And you hunt Germans

sometimes

Oh so the German detection thing is based on grammar

You recognize specific patterns of German translated literally by the speaker

I mean, it doesn't happen that often

I remembered that one time and a quick search showed me the German detection history

but it's always funny to me when it does because I have to do a mental double take to figure out why that sentence made perfect sense to me even if it isn't correct English

I know what you mean, the Master's degree is in English and Professors do not speak perfect English

I mean I don't speak perfect English either but sometimes the Italian style is quite stong :P

@Feynman_00 most of the history of "German detected" in this chat is others detecting me as German!

from a cursory glance usually because remembering the auxiliary construction with "do" for English questions is annoying :P

@ACuriousMind dang, I read that assuming that was you all the time...

@ACuriousMind there is no such thing in Italian either

Also, sometimes it might sound redundant: "there exists--->does there exist...?"

I mean, it's natural grammar - it doesn't have to make sense

@ZeroTheHero I'm thinking about it.

There's less of a case for it right now, I'd say

Bell/CHSH is much better explained than CPA already

by orders of magnitude

both in general science stuff / on the internet / on PSE

so there's less to say that isn't already on PSE

... but, on the other hand, it's a good opportunity to get something solid on entanglement on HNQ and get people clicking and learning, so... I don't know

@ACuriousMind Any idea what the Lagrangian that gives out the autoparallel equation would be, for some arbitrary connection?

Polyakov doesn't have anything to do with the connection

@Slereah I don't know, and the only thing I can find is this

It's a strangely uncommon topic

Even just autoparallel equations that aren't the geodesic equation aren't that common

I mean, they are common when discussing general connections - they define the parallel transport operator, after all

but you rarely have to solve them explicitly :P

and I really don't see why a) most non-physicists would care about getting that equation from an action principle and b) most physicsts would care about general autoparallel equations instead of geodesic equations

in unrelated news, if you want to feel old, here's a HNQ asking how people got "apps" before "the internet", and it's on retrocomputing.

If I needed a program to do something I just found one.there

@ACuriousMind just need to check if my idea of how to define mass in GR makes sense

Or more precisely if mass defines a length scale

I can find papers on the topic for field theories, but not so much for curves

But since mass doesn't actually matter for the autoparallel EoM, I need to throw in some potentials into the mix

There actually is a trick to separate geometric terms from forces in a general EoM, but I need to show how the mass relates to these

In quantum teleportation, between Alice and Bob, at the end of the protocol, what happens to the qubit that Alice wanted to transmit to Bob? As described in this wiki, does "destroyed" mean that its state has been changed? And so, if Alice were to measure it, it would be different state than if Bob measured the qubit he received?