The h Bar

Relativisticcucumber

3:00 AM

@SillyGoose my gr course treated a few metrics

Silly Goose

Oh i see

then it makes more sense

Relativisticcucumber

mink, FLRW, schwarzschild, kerr? im not sure if im remembering these exactly right

Silly Goose

Omg mink

naturallyInconsistent

lol mink

Relativisticcucumber

plus learning index notation which u have struggled w in this chat for months XD

im just saying maybe educate urself before u trivialize one of the hardest subjects of all time publicly -- sounding a bit like someone else in this chat

2

naturallyInconsistent

3:03 AM

I think deriving Schwarzchild, and then working out one of 1) Mercury's precession, 2) Eddington's deflection of light by Sun is almost not-measurable, 3) GPS time dilation, is quite helpful as a GR course.

lol

Silly Goose

i didn’t ever claim gr was easy or trivial

Relativisticcucumber

i think ur message did trivialize the course. i also think you could have easily educated urself enough to answer ur q / thought ab it a bit more and realized that its not different than any other subject

naturallyInconsistent

yeah, for some reason quite a lot of people have serious troubles with index notation. One of my online students complained about it too. Miao miao am very lucky to have had really good introduction to that, so much so that it never felt difficult. Instead, Hodge dual is really confusing for meow, because levi-civita in Cartesian is so easy that miao miao never got to practice the Hodge dual version

Relativisticcucumber

@naturallyInconsistent blebs

naturallyInconsistent

@Relativisticcucumber It is absolutely crazy how some people just immediately see ridiculous ways to do things. Ladder operators just jumped out of the blue between Dirac and Schrödinger, and they got so far as to factorise the Coulomb potential too. Schwarzchild's solution was also something that Einstein wasn't even anywhere near expecting. He was expressing doubt that it could even be solved exactly, and if it were to be solved, it would be far after his death. It wasn't supposed to be within years

naturallyInconsistent

3:26 AM

oops, miao miao iz on tv again

Silly Goose

4:41 AM

@Relativisticcucumber you are rightso

Silly Goose

5:33 AM

how is this question lacking clarity :P (my own question): physics.stackexchange.com/questions/813771/…

John Rennie

5:43 AM

I wouldn't closed it, but it does seem unclear to me exactly what you're asking as you've pretty much defined it in your question.

naturallyInconsistent

They are trying to ask if you have read a standard quantum computing textbook and learnt one of the various ways to measure the degree of entanglement fromt here. Those use the density operators and you might love them

Silly Goose

5:57 AM

i am wondering how people interpret the sentence "How do I understand precisely in mathematical language the description of (pure and mixed state) entanglement as inducing a special type of correlation between measurement outcomes of subsystems?"

this to me is clearly not asking about anything to do with the textbook definition of entanglement since the textbook definition of entanglement says nothing precisely about correlations between measurements of subsystems

the only textbook i've seen a somewhat detailed discussion of what i am asking for is "Quantum Information Meets Quantum Matter" by Zeng et al. but it's not in mike and ike nor schlosshauer etc.

naturallyInconsistent

No, no, there are mathematical quantities that measure the degree of entanglement.

Entanglement witness

In quantum information theory, an entanglement witness is a functional which distinguishes a specific entangled state from separable ones. Entanglement witnesses can be linear or nonlinear functionals of the density matrix. If linear, then they can also be viewed as observables for which the expectation value of the entangled state is strictly outside the range of possible expectation values of any separable state. == Details == Let a composite quantum system have state space H A ⊗ H...

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