The h Bar

« first day (2535 days earlier) ← previous day next day → last day (2691 days later) »

lılostafa

21:02

Is this conversion correct:

Semiclassical

@0celo7 huh

lılostafa

(B is coordinates, just like r)

Emilio Pisanty

@PhysicsMeta boy oh boy, is that one ever a bucket of whoa

lılostafa

I don't see how $\sin \theta$ become $\frac{\mathbf B}{2|\mathbf B|^3}$ after conversion from spherical to cartesian coordinates

Semiclassical

@EmilioPisanty that's a whole bunch of something

lılostafa

21:12

@ACuriousMind Can you help with this ^?

0celo7

@ACuriousMind Ok, so the construction of a covariant derivative from a vector bundle horizontal distribution is much harder than for principal bundles.

Semiclassical

@EmilioPisanty looking at the one answer: the OP took all his comments there and reposted the entirety of it in his edited question

wtf

0celo7

$$\nabla_v\sigma =\mathrm p(\mathrm p_\mathrm{v}(d_p \sigma\cdot v))$$

ಠ_ಠ

Semiclassical

...ow

that hurts just to look at

@0celo7 what are those p's here

projection operators?

0celo7

and then $$H_y=\{ds\cdot u-j_y\nabla_u s:s\in\Gamma(E), s(\pi(y))=y, u\in T_{\pi(y)}M\}$$

and that $j_y$ is the vector bundle isomorphism $\pi^*E\to VE$

@Semiclassical various ones, yeah

there's four or so in this construction

Semiclassical

21:22

ugh

0celo7

there are five bundles involved

and in my GR problem there's Hom bundles and tensor bundles, etc.

I hate bundles

Semiclassical

yea, uh

i have to go

and do something else

and stay the hell away from that mess

0celo7

@Semiclassical there's a reason why connections on vector bundles are usually presented as friendly derivative operators

So from this, I can see roughly what Christodoulou is saying. I believe him. Time to move on.

@Semiclassical this "mess" is attempting to coherently describe invariants for Lagrangian-type theories in GR

Semiclassical

It’s meant for braver men than I, then

0celo7

@Semiclassical Ahhhh, this nonsense is to get rid of the pseudotensors

Trade one evil for another :)

Semiclassical

21:32

lol of course

Emilio Pisanty

@Semiclassical yeah, I know

Semiclassical

Conservation of horror

Get rid of it in one place, it pops up somewhere else

(I like to joke that there’s a conservation of absurdity in QM interpretations)

0celo7

@Semiclassical clearly you haven't heard my goblin interpretation

vzn

21:48

in theory salon, 42 secs ago, by vzn

Quantum Inside: Intel Manufactures an Exotic New Chip / MIT tech review

↑ 17 qbits! :o

Mithrandir24601

22:07

@vzn I read that, was like "but we knew this months ago!" Then realised they were talking about Intel, not IBM :P

0celo7

@Semiclassical

oops

Semiclassical

22:29

@0celo7 The goblin interpretation: Goblins got a wizard to do it

Physics Guy

Hello again.

Sir Cumference

23:25

Why is it that we usually refer to a paper by the names of its authors, rather than the name of the paper?

0celo7

23:47

@SirCumference papers tend to have very generic names

Author + subject tends to narrow it down better

HsMjstyMstdn

Papers also tend to have longer names and some of the terms in the name are oft repeated. Author names are more unique. Pairing the two gives you the best search results. I think.

« first day (2535 days earlier) ← previous day next day → last day (2691 days later) »

all rooms

Transcript for

Oct12

Oct '1713

Oct14

General chat for Physics SE (physics.stackexchange.com). For M...

join this room
about this room

00:00

06:00

12:00

18:00

all times are UTC