The h Bar

Mozibur Ullah

7:00 PM

@ooolb: well, I remembered it as noise ;).

ooolb

noise sounds fucked

if it doesn't make your ears bleed then either you have autism or it's not noise.

but that's the point

dmckee

@Abcd Escape speed represents the parabolic orbit speed at that location. It divides free trajectories from bound ones. Don't get hung up on the verbiage used for introductory treatments.

Mozibur Ullah

Aube is a Japanese noise musician

You got a thing for all things Japanese?

ooolb

nah what do you take me for a weeb?

dmckee

We're rarely interested in the exact value, but we are interested in knowing that we need delta V for escape, plus transfer orbit insertion, plus destination burn, plus maneuvering reserve.

Mozibur Ullah

7:03 PM

Whats a weeb? Is that a new meme?

dmckee

It's just one part of a bigger picture.

0celo7

@MoziburUllah a westerner obsessed with japanese culture

Mozibur Ullah

Seriously?! The things you learn. What do you call a Japanese guy obsessed with all things Western?

ooolb

sometimes im a lowkey otaku but i don't make it obvious

Sir Cumference

Am I supposed to believe "Fourier" is pronounced "Fourieh"?

ooolb

7:04 PM

if you ask me irl if i watched a certain anime i'd say no even if i did

@MoziburUllah a beew

Mozibur Ullah

LOL!

Aristotle said that all philosophers agree that the roots of all things are contraries. So you'd get on fine with him.

dmckee

@bolbteppa It also helps there there are generally few meaning that make physical sense and fewer still that are interesting.

Mozibur Ullah

LOL is a palindrome.

dmckee

There is a lot of implicit knowledge that goes into reading physics.

Mozibur Ullah

Ok. I gotta go to the shop buy some stuff. I'll be back later.

Cheerio.

ooolb

7:08 PM

@MoziburUllah that sounds sexual

Sir Cumference

@SirCumference Ugh it was true

My prof lied to us

ooolb

are you talking to yourself

how many all nighters r u on now

Sir Cumference

@SirCumference No I'm not

I dunno 0.5 right now

ooolb

how can you be on 0.5 all nighters

Sir Cumference

@ooolb Technically it was 0.75 all-dayers

...I think

ooolb

7:12 PM

what

Sir Cumference

I dunno I'm tired

I had 3 cups of coffee but I don't think it's doing anything anymore

ooolb

i always have coffee and it doesn't ever do anything

even when i don't have it i feel the same

Sir Cumference

@ooolb Ah, it was a half-nighter

ooolb

$$..............$$

@ACuriousMind quiet today

what's the matter

Anonymous

This is quite inspiring.

Sir Cumference

7:18 PM

> Otaku

Isn't that another name for weeb? (no offense, genuinely thought it was pejorative)

CooperCape

@SirCumference I wouldn't say that it's the nicest of terms to describe yourself with

Sir Cumference

@CooperCape urbandictionary.com/define.php?term=stack%20exchange

Urban Dictionary is pretty accurate

CooperCape

God sometimes I love UD

Wait lemme find one of my faves

ooolb

i bet JD wrote that entry

Sir Cumference

urbandictionary.com/define.php?term=stackoverflow

Love this

CooperCape

7:30 PM

This one just cracks me up (Nsfw probs... don't click if you're gonna get sensitive and flag me...)

ooolb

this is too accurate it's scary

Sir Cumference

@ooolb urbandictionary.com/define.php?term=bloo

Is this where you got it from?

ooolb

which one

Sir Cumference

Top

ooolb

uhhh no

that's a coincidence

nothing against bloo though

i feel like #3 depicts me quite well

0celo7

7:33 PM

@ooolb who do you think wrote that

ooolb

karl rominger

0celo7

spell that backwards

ooolb

regnimor lrak

holy fuck

0celo7

yep

they used to call me Lrak Ocelot.

2

I proved myself in Regnimor. Got the Medal of Lenin there

CooperCape

Am I missing something here.

I feel like I am.

Mithrandir24601

7:36 PM

@CooperCape ... Well... That escalates rather quickly... O.o

Sir Cumference

@CooperCape 90% sure it makes no sense, don't worry

ooolb

@SirCumference u wot

Mithrandir24601

@SirCumference It appears similar to something from Thor...

CooperCape

@Mithrandir24601 Ejected from the game though... Tbh learnt a lot about baseball from that.

ooolb

@SirCumference this is a physics chat

90% aint good enough

sigma 5 or go home

Sir Cumference

7:39 PM

@ooolb It's sigma 1.6 or so. Engineers would round it up to 2.

Accurate enough for me

CooperCape

(looks up sigma 5 under the assumption that it's $>90\%$)

0celo7

engineers do 2 sigma? Are you insane

CooperCape

@SirCumference I mean 2 is basically $\pi$ and that's a Greek thing so you may as well say $\pi$ there.

0celo7

this whole "Engineers use 3 for $\pi$" thing is nonsense. They don't even know the order of magnitude. They just hit the $\pi$ button.

user685252

22/7

CooperCape

7:41 PM

See on a good 'ol Casio fx 83GT/99IES you gotta shift+pi that so it's a bit more effot.

Emilio Pisanty

@0celo7 I was going to ask "there's a $\pi$ button?"

It's evidently been too long since I used a calculator to do science

0celo7

I use a calculator often even for pure math

Emilio Pisanty

it's just esc-p-esc now

Sir Cumference

@CooperCape Really, a simple ceiling function will bring it up to 4. Clearly we've gotten to 4 sigma

CooperCape

(I still don't know what x sigma is...)

(I'll play along)

Sir Cumference

7:42 PM

@CooperCape standard deviations :P

ooolb

@SirCumference what

CooperCape

Yeah... yeah uh huh.

Sir Cumference

@ooolb We've just soundly proved that 90% $\approx$ 4 sigma

CooperCape

Pretty much.

And I didn't even know what sigma was until 1 minute ago.

ooolb

sigma has nothing to do with that

Sir Cumference

7:43 PM

Any denial is just pedantry

CooperCape

Hater.

ooolb

it's a measure of how many greek philosophers would approve of what you said

like 1 sigma would be astrotle

excuse that

CooperCape

Think I remember one of my old RS (religious studies) teachers saying my friend would be a good philosopher because "Aristotle was ugly too..."

Sir Cumference

@ooolb still don't know who asstrotle and astrotle are

0celo7

that was an honest typo

Emilio Pisanty

7:46 PM

dammit

ooolb

i love me some dry aristotle

Emilio Pisanty

there we go

Sir Cumference

:41562117 Flawless :P

0celo7

@EmilioPisanty I didn't see that

ooolb

@0celo7 can you prove it

Emilio Pisanty

7:47 PM

@SirCumference thanks. It takes some work.

ah, got it

@0celo7 $\color{lightgray}{\mathsf{(removed)}}$

ooolb

wait can we still redefine latex commands

or was it nerfed

user685252

Sir cumference = Sir pie*d

CooperCape

$\small{\color{lightgray}{\mathrm{(removed)}}}$?

Sir Cumference

@user685252 Sir ~2D

CooperCape

actually that's too small

hmmm

can't get that font really.

Emilio Pisanty

7:50 PM

@CooperCape I don't think mathjax supports arbitrary font sizes

but heck, maybe it does?

CooperCape

you can go \$\small{}\$

0celo7

@ooolb check discord

ooolb

i forget how it works

$\renewcommand{color}{test}$

user685252

3D sounds better @SirCumference

CooperCape

I accidentally redefined color the other day to "I fucked up" so yea..

$\color{f}$

0celo7

7:51 PM

@EmilioPisanty oh

now I see

Emilio Pisanty

@CooperCape oh, are we breaking mathjax again?

excellent

0celo7

good way to get the mods angry

CooperCape

@EmilioPisanty Hey, it wasn't me this time!

Sir Cumference

it's so cold out...

user685252

(22D)/7

CooperCape

7:52 PM

Anyway last time it was under the watchful eye of Bernado

Emilio Pisanty

@0celo7 yes, that it is

CooperCape

I didn't even know you could...

until he started tryin to

Emilio Pisanty

@CooperCape let's just say that MathJax's a bit... lax... in how it interprets \newcommand

Slereah

Why did Schrodinger choose to kill the cat

When literally any other choice would have worked

CooperCape

@EmilioPisanty Sad reaccs only

0celo7

7:53 PM

because he was an analyst

Slereah

Was Schrodinger an analyst?

Emilio Pisanty

and in how it behaves if one draws a recursion loop between command definitions

ooolb

ewh

0celo7

he hated cat(egorie)s

Slereah

I don't actually know what he did outside of QM

ooolb

7:54 PM

@Slereah he was a player

Emilio Pisanty

like, say, if you felt like making the mods angry at you, you could define a command \alpha that called \beta, and a command \beta that called \alpha

user685252

Threesomes

Slereah

"Early in his life, Schrödinger experimented in the fields of electrical engineering, atmospheric electricity, and atmospheric radioactivity, but he usually worked with his former teacher Franz Exner. He also studied vibrational theory, the theory of Brownian movement, and mathematical statistics."

Lame

Sir Cumference

Schrödinger's cat

Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a cat that may be simultaneously both alive and dead, a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur. The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics. Schrödinger coined the...

ooolb

@Slereah vibrational theory ( ͡° ͜ʖ ͡°)

Sir Cumference

7:55 PM

> Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics.

Slereah

Yes, I am aware

Sir Cumference

He'd be rolling in his grave if he knew how many people took his example seriously

Slereah

but he could have made the experiment give a treat to the cat

or not

and the point would be the same!

user685252

Not as dramatic

Sir Cumference

Optimist test: Do you consider the cat half alive, or half dead?

Emilio Pisanty

7:56 PM

@Slereah not quite as impactful

ooolb

wasn't it einstein who said he'd rather fucking put a bomb in the box to schrodinger?

Emilio Pisanty

though here's a good way to make the thought-experiment more impactful:

Slereah

I seem to recall a similar thought experiment

On the topic of free will

But much nicer

Emilio Pisanty

forget about the glass bottle with the poison, just strap the cat's head under the hammer's path

Slereah

It's just like

Place two carrots at equal distance of a donkey

Which one does he pick!

That would have been much better

user685252

7:57 PM

Neither

Slereah

Schrodinger's donkey

user685252

It dies of starvation

CooperCape

So my laptop just decided that it would be just great if the volume button no longer controlled the volume but brought up the task manager! Thanks volume button :D

ooolb

@Slereah reminds me of ship of theseus

Emilio Pisanty

@Slereah in Spanish that would be "el perro de las dos tortas"

ooolb

7:58 PM

idek who i am anymore

Sir Cumference

@Slereah We need more Hypothetical Animal Rights Activists in the world

ooolb

fucking identical particles in qm

Slereah

@SirCumference To defend Schrodinger's cat and Pavlov's dog

user685252

Pavlov was different

Slereah

Why, because he was a COMMUNIST?

user685252

7:59 PM

S--->R

ooolb

71

Slereah

"Despite praise from the Soviet Union government, the money that poured in to support his laboratory, and the honours he was given, Pavlov made no attempts to conceal the disapproval and contempt with which he regarded Soviet Communism."

Oh apparently not

user685252

Stimulus ---> Response

ooolb

seventy one

Sir Cumference

> Nobody really doubts that the presence or absence of the cat is something independent of the act of observation. ~Albert Einstein

So does JD deny QM?

user685252

8:02 PM

Does the tree make a sound?

ooolb

@SirCumference citation needed

I believe in Duffield and the Debunk

Sir Cumference

Schrödinger's cat

Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a cat that may be simultaneously both alive and dead, a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur. The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics. Schrödinger coined the...

ooolb

it's my favourite show

Sir Cumference

Classic Einstein

ooolb

@Slereah ^ do you like that

DanielSank

8:24 PM

Hi, everybody.

CooperCape

ohai

user685252

heya

Semiclassical

it's certainly true to say that Schrodinger's conclusion from his cat scenario was not "QM says the world behaves in a way contrary to intuition" but rather "what we think QM says about the world is so contrary to intuition that it can't possibly be the right interpretation"

That, however, tells us nothing about how we should understand QM.

Hence why I always feel a bit impatient when I hear someone say that Schrodinger presented his cat as an absurdity. It's true, but that's a historical question not an immediately scientific one.

DanielSank

Schrodinger and contemporaries understood less about QM than we do now.

Schrodinger's cat is still important and interesting, but it's slightly less magic than it used to seem.

Semiclassical

my own touchstone for QM weirdness is Stern-Gerlach

Emilio Pisanty

8:38 PM

Semiclassical

lol

DanielSank

@Semiclassical But it's not that weird.

Emilio Pisanty

(due credit to SMBC)

Semiclassical

no, it's not

CooperCape

I blame Newton for gravity

If Newton hadn't invented gravity we could float

Semiclassical

8:39 PM

mostly I like that one can describe it by analogy with how polarizers work in optics

DanielSank

no you can't :-)

Not with classical optics, anyway.

user685252

SemiClassical?

Semiclassical

Put two perpendicular polarizers in a row---no light goes through. Put a third polarizer at some angle relative to both of them---light goes through.

DanielSank

@Semiclassical Yeah.

So?

Semiclassical

That's the entirety of the analogy I had in mind.

DanielSank

8:41 PM

oh

Semiclassical

@CooperCape Newton nothing. I blame Aristotle for inventing the idea that our natural state of being is to be on the ground.

DanielSank

Ok but with Stern Gerlach, you can put one magnetic field pointing up/down and you get two beams, one going up and one going down. Now you put a left/right field in one of those beams and you get two beams: one going left and one going right.

CooperCape

Aris-thot-le

DanielSank

@Semiclassical Aristotle did not really understand the scientific method.

2

Emilio Pisanty

@Blue w/CC @JohnRennie Hey, I wanted to check in on this before it got too late. On further thought, this isn't quite how you should think of Landau levels. Classical orbits in a magnetic field are never cycloids, they're always circles. The heuristic I was thinking of is this:

i.e. a superposition of many circular motions, each with some different quantum mechanical phase (that' s the $e^{ikx} $ factor, which should be handled with care - you might have a definite canonical momentum in the $x$ direction, but the kinematic momentum will differ from that).

it's not perfect, but it helps get some intuition

Semiclassical

8:44 PM

@EmilioPisanty classical orbits in a magnetic field alone, anyways.

Emilio Pisanty

also, while I'm on old messages

Semiclassical

you do get cycloids if you include a perpendicular electric field iirc

E-cross-B drift and all that

Emilio Pisanty

@Semiclassical yeah, that too

also hopping semicircles at an edge

Semiclassical

right

Emilio Pisanty

which are extremely important for current research

Semiclassical

8:46 PM

yup. huzzah for protected edge states

Mozibur Ullah

@DanielSank: That would be anachronistic. If you popped into a time machine and asked Aristotle about the scientific method I'm pretty sure he'd grok it. Actually, he grumbled somewhere in Physics about his contemporary critics asking rhetorically 'do they think that we do not observe'.

Emilio Pisanty

@Blue keep in mind that most useful treatments of Landau quantization tend to be geared towards the solid state, and the 'particles' you're quantizing are really quasiparticles, i.e. joint excitations on the states of many particles, which then act like a single-particle system. The interesting bit isn't increasing in size, but in increasing complexity of the particle, i.e. pushing towards skyrmions and whatnot.

Semiclassical

textures and all that, yeah

DanielSank

@MoziburUllah I meant more than his thinking doesn't reflect the scientific method.

He'd grok it if someone explained it, but I think he was so hamstrung by lack of scientific equipment and knowledge that he resorted to just making stuff up.

Emilio Pisanty

@Semiclassical textures?

Semiclassical

8:49 PM

yeah. that's what that's often referred to as: a skyrmion spin texture

Emilio Pisanty

ah, spin textures, yes

speaking of skyrmions, have you got any wisdom on hopfions that you might care to share?

Semiclassical

noooope

Emilio Pisanty

ah well

Mozibur Ullah

@danielSank: I've read his Physics and it doesn't read like he's making things up; its written like a contemporary paper, he talks discusses the finds and suggestion of his predeccesors looking for the strengths and weaknesses and then going to give his own view. Stephen Hawking talks about Aristotle in a Brief History of Time without being patronising. I'm not sure why physicists pick on Aristotle so much.

Susskind does it too.

Emilio Pisanty

@Semiclassical I'd quite like to understand this solution better. But it looks like I'll just have to wait for the paper like everybody else.

Mozibur Ullah

8:54 PM

He showed that you could do physics qualitatively despite the lack of good equipment.

Semiclassical

weird

Emilio Pisanty

yeah, it's really cool

Semiclassical

I think comparing Aristotle to modern science is just not a fair comparison

Mozibur Ullah

I wasn't trying to compare the two...

Semiclassical

no, you weren't

skullpatrol

8:56 PM

Contrast?

Mozibur Ullah

It was the introduction oh his work by Islamic scholars, like Averroes which kicked of the scientific revolution in the modern era; it didn't come from nowhere.

Anonymous

@DanielSank I guess you need to define $\lambda$ in a better manner. "Probability per unit time" isn't a standard term (afaik). According to your treatment, $\lambda$ is the time average of the probability density function. And $\lambda \Delta t$ gives an approximate value, not the exact (which I'm happy you addressed in your PSE post).

Anonymous

Also, it would be nice if you use $\Delta t$ instead of $dt$ there, since writing $dt=T/N$ looks a bit handwavy to me ($dt$ being a differential). You can later take $\Delta t \to 0$ and $N\to \infty$.

Anonymous

Feel free to give any counter arguments you might have, I'm interested

DanielSank

@Blue In the first part of the answer, I never used $dt$ to mean anything other than a finite time interval, so there's no hand-waving.

Perhaps the notation is confusing though. You can edit to use $\Delta t$ if you like.

Anonymous

8:59 PM

@DanielSank Yeah, that would be nice :)

skullpatrol

No one can see you waving your hands on the internet :P

Anonymous

Also if you could define $\lambda$ properly in the post...

DanielSank

@Blue It is defined just fine.

The probability of an even happening is $\Delta t \lambda$, as long as $\Delta t \lambda \ll 1$.

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