The h Bar

2:42 AM

@Semiclassical lol ee cummings was the original! :) ... enjoyed his Sims4 review! o_O

Zero Punctuation is a series of video game reviews created by English comedy writer and video game journalist Ben "Yahtzee" Croshaw. Since the series began in 2007, over 600 episodes have been created, which have been published weekly by internet magazine The Escapist. Episodes typically range from 5 to 6 minutes in length. Videos provide caustic humour, rapid-fire delivery, visual gags and critical insight into recently released video games, with occasional reviews of older games and retrospectives of the industry itself. == History == Prior to Zero Punctuation, Croshaw primarily authored content...

More Anonymous

5:43 AM

@ACuriousMind I don't want to repeat the fiasco of last time where I put a bounty and stopped the review process. However, I feel this time it's slightly different as "I accidentally pressed post while editing and figuring out a post .. Panicked, tried to edit it in real time, etc." Since then I feel last edit makes the question on an acceptable level?

But maybe I'm fooling myself since the traffic to the question has reduced? Which is why I'd like to put a bounty? I would be grateful if you were to share your thoughts? physics.stackexchange.com/questions/503209/…

Also denizens of the chatroom does anyone know any great question posts where the OP puts his question (on a nuanced topic) in a clear way? I could do with learning how to put your point across in such situations? Basically, I'm asking for well-asked, long (?), nuanced question post. Feel free to ping me with such link?

Trying to work on my communication skills :/ (suffered too long due to them)

More Anonymous

6:05 AM

@vzn Relevant (while I think your usage isn't as bad as mine): chat.stackexchange.com/transcript/message/51750454#51750454

Physics Meta

9:34 AM

0

Q: Examples of the questioner going the extra mile?

I'm trying to improve my penning-down-a-question skills. I have been through the guidelines and this great meta post. I was hoping to get some examples(/list) of a well phrased question? In order to help my own question framing? Would any user like to provide such a examples(/list)? More specifi...

discussion

2

More Anonymous

12:04 PM

@AbhasKumarSinha I'm wondering if there's an Indian version of this social experiment: youtube.com/watch?v=lFneXnGwQAI

Yashas

1:58 PM

Consider an operator $\hat{O}$. We can talk about the hermitian of the operator. Suppose we express the operator as a function, say $\frac{\partial}{\partial x}$, what does it mean to take the hermitian of this?

If you decompose hermitian into conjugate and transpose. What does it mean to take the transpose of the derivative operator?

heather

2:12 PM

if i have a vector that represents a qubit state after measurement, is it correct to renormalize it by 1) multiplying by the projection matrix, 2) calculating the norm, and 3) multiplying the state vector by $1/\sqrt{\text{norm}}$?

because i'm getting results where the probabilities don't sum to one, so clearly i'm doing something wrong.

Emilio Pisanty

@heather no, you divide by the norm, not by its square root

you're probably led astray by the fact that $⟨\psi|\psi⟩$ is the square of the norm. So you divide by $\sqrt{⟨\psi|\psi⟩}$

(also: hi, heather!)

heather

(hello =) okay, that makes some sense

let me see if that gets me a reasonable answer.

Emilio Pisanty

how are your experimental adventures going?

heather

good. i'm really busy with school, so i don't have enough time for my personal projects as i'd like.

i'm finally getting really close to finishing my quantum computer simulator though!

how have you been?

(...and yep, that got me an answer where the probabilities sum to one! thanks!)

Emilio Pisanty

2:40 PM

@heather ;-)

@heather working like crazy, as always.

@heather nice!

so are you starting college this year? next year?

Emilio Pisanty

3:04 PM

physics.stackexchange.com/questions/503550/…

hmmmm

(10k+ only, sorry)

it's good to see more people actively using their Delete votes, so it's not just me, @KyleKanos and @JohnRennie

... though this one was cute enough that I kind of regret its disappearance =P

PM 2Ring

There have been a few rather flakey questions & answers lately. I blame the upcoming equinox. ;)

Aaron Stevens

3:22 PM

I voted to delete because I am actually about to publish some theory on this.

For some reason I cannot tag anyone? It gives me an unknown error

@EmilioPisanty Working yet?

Oh there we go :)

Abhas Kumar Sinha

@MoreAnonymous For me I guess, I can easily differentiate between a Korean guy and Japanese guy, but honestly I find most of them similar to each other. Even Europeans look very similar to me. I'm comfortable only with Indians because that's the part I can differentiate.

@MoreAnonymous reminds me of Tollywood XD , still they can't match that kind of performance :) lol

@MoreAnonymous When you are in India and want to trigger half of the Indian population at a single go!

“Cricket is boring.”
Headlines next day— “Man. 42. Found crying after random mob got involved with bats and misidentified the balls.”

More Anonymous

3:37 PM

42 is the answer to the universe after all

Abhas Kumar Sinha

@MoreAnonymous yesssss.....

42 and Douglas Adams - Numberphile

►

42 (answer)

42 is the "Answer to the Ultimate Question of Life, the Universe, and Everything" in The Hitchhiker's Guide to the Galaxy books. It was computed by Deep Thought, the second greatest computer ever. The descendants of Deep Thought's creators are upset by the numeric nature of the answer, not understanding what to do with it or what to tell the people who had commissioned the 7.5-million year project.When asked to produce The Ultimate Question to go with the answer "42", Deep Thought admits it is not capable of computing that itself, but that it can help to design an even more powerful computer...

PM 2Ring

@AaronStevens Some weird bug. It was happening in the Python room too, for several minutes, and that's on a separate chat network to this room.

More Anonymous

@PM2Ring Same!

Sir Cumference

3:53 PM

@heather Hey! How's life? :)

Novalium Company

4:18 PM

Hey Jude

ur 42

freshavacadoo

spongebob doodle doo

Why the heck 42...

Me: "What's the purpose of life?"
God: "42"

It's not 42, cuz I have 0 friends, not 42

HA

Aaron Stevens

@NovaliumCompany You feeling ok...?

More Anonymous

4:46 PM

@NovaliumCompany School didn't go well?

ACuriousMind

4:59 PM

@MoreAnonymous This question, too, has a pending close review. It should give you pause that your questions keep getting close-voted, this is not the case for most questions which are self-contained and clear.

This question in particular a) expects users to click at least two links (and potentially read an entire paper) to understand what you're talking about, b) has a colorful picture whose significance is never explained and whose origins is unclear,

c) is inconsistent starting from the point where it talks about the operators $\partial^k_t x_i$. If the observers "agree" on $\partial^k_t x_i$ for some $k$, then necessarily $\partial^k_t x_1 = \partial^k_t x_2$ as operators. Therefore, if $\psi_1 \neq \psi_2$ for at least one pair of $\psi_i$, these operators cannot be invertible and what follows is nonsense. If $\psi_1 = \psi_2$ for all pairs, then the question is moot to begin with.

More Anonymous

@ACuriousMind c. I'm not arguing for that at all

Ryan Unger

Sup

ACuriousMind

@RyanUnger Inf

More Anonymous

@ACuriousMind I'm actually confused let's say we both measure the rate of change of acceleration to be 0. But I know the boundary conditions. Then I can play the game I'm talking about

It's not a great transformation law

But it's a toy model

a. Alright, I'll try to make it self- contained with having the click the link.
b. Well, yea I see that now

I'll massively re-edit the question. Deleting it for now

Emilio Pisanty

The Bizarre Behavior of Rotating Bodies, Explained

►

3

that's one fantastic video

with a guest appearance by Terry Tao's MathOverflow answers!

More Anonymous

5:22 PM

@EmilioPisanty Does he give Terry his due credit?

JMac

@MoreAnonymous I haven't actually watched the video, but it's the top link in "References:" in the video description, so that seems like a yes.

More Anonymous

@JMac Ah. That's good to know :)

ACuriousMind

@EmilioPisanty Indeed, pretty good!

Emilio Pisanty

@MoreAnonymous yes, obviously

@MoreAnonymous FWIW, (b) is an absolute, complete deal killer for me. Nothing tells me, as a prospective answerer, that you have no respect for the time I might invest in answering your question, quite like math done up in a colourful image that I need to struggle to decode instead of plain MathJax.

JMac

@EmilioPisanty So you haven't memorized all Terrance Tao's answers on Math Overflow and just recognized the video was taking content from them?

Emilio Pisanty

5:31 PM

@JMac I'm still doing the 2014 answers and haven't yet worked my way back to 2011

JMac

@EmilioPisanty I'm about halfway through, but I'm working in the other direction.

Emilio Pisanty

@JMac it seems that together we might make a decent substitute to the Stack Exchange data dumps, then =)

More Anonymous

@EmilioPisanty Yes, I can see that now. My bad. I should have taken much more time. I'll spend more time with how to phrase the question in a concise and clear manner rather than just writing it.

Emilio Pisanty

@MoreAnonymous good to hear.

Aaron Stevens

6:22 PM

@EmilioPisanty The explanation of why the liquid filled cylinder flips to the 3rd principle axis doesn't seem strong to me. I feel like it is missing something. Since when is motion determined by minimizing kinetic energy? And why does kinetic energy dissipation mean it has to end up rotating about an axis where the kinetic energy is less (I assume for the same angular momentum)?

ACuriousMind

@AaronStevens I understood it as implying that the liquid will dissipate some energy through internal friction or friction with the walls of the container.

What's more mysterious is that it has to stop dissipating energy once the minimal kinetic energy for the given angular momentum is reached

Aaron Stevens

@ACuriousMind I understand where the dissipation comes from. I don't thinks its as clear as to why dissipation means it must move to rotating about the 3rd principle axis

ACuriousMind

@AaronStevens Because angular momentum is conserved!

Aaron Stevens

@ACuriousMind Ah ok... yes of course

@ACuriousMind I guess the dissipation depends on rotation about a different axis

ACuriousMind

You can only conserve the angular momentum if the motion changes such that the same momentum is achieved with less rotational kinetic energy - and the greater the momentum of inertia abot an axis, the slower the rotation about that axis needs to be to achieve the same angular momentum

Aaron Stevens

6:28 PM

@ACuriousMind Right, of course. If it stayed rotating about the same axis then the angular momentum would be changing. Rookie mistake :)

ACuriousMind

@AaronStevens Sure, but I'm having a difficult time imagining that e.g. internal friction ceases just because the axis of rotation is different

Aaron Stevens

@ACuriousMind I suppose it would have something to do with the fluid not being able to "match" the cylinder?

ACuriousMind

"Friction between a liquid and a container is zero when the container rotates about its principal axis with the largest moment of inertia" seems a suspect claim to me

Aaron Stevens

@ACuriousMind Yeah... that is something interesting to think about

@ACuriousMind And yet if the 3rd PA is the one that allows for the smallest KE, then doesn't that mean the claim must be true?

ACuriousMind

Yes (because the angular momentum can't go anywhere else), but it just seems strange

...and people think QM is weird :P

Aaron Stevens

6:36 PM

@ACuriousMind So then once it gets to the 3rd PA is must be that the fluid's rotation matches the cylinder's rotation

ACuriousMind

Yeah, I guess everything must align such that the fluid is perfectly rotating with the container at that point

Aaron Stevens

Now I feel like I need to write a sci-fi novel where the evil scientist's plan is to build some massive structures at the poles of the Earth to get the Earth to flip

Maybe that was Santa's plan all along

enumaris

ugh...implementing this layer in tensorflow is a pain in the butt...

Emilio Pisanty

@AaronStevens motion is constrained by the available kinetic energy

Aaron Stevens

@EmilioPisanty Yeah, ACM pointed out the obvious to me haha. Thanks though

Emilio Pisanty

6:40 PM

Yeah, just caught up

Aaron Stevens

I think the video would have benefited from making an animation similar to the one explaining the IAT but using one of the other PAs to show why those orientations are stable. I can think through them on my own, but it would still have been cool to see.

Aaron Stevens

7:50 PM

0

Q: What are the key differences between a particle and a wave?

When do we call something a particle, and when do we call something a wave? Do we call something a particle when it is highly localized? If that's right, then a wave packet is a particle. Do we call something a wave when it is not localized and when it shows interference pattern?

wave-particle-duality

I feel like the answer just accepted is missing some things that need to be addressed

Scientist Smith YT

@JohnRennie So sorry, for the delay on my question. My questions are about superconductivity. We all know that little portions of magnetix flux do flow through a superconductor when chilled down. These are called fluxons. My question is, what do fluxons look like? And what are they? (Do they act like condensed air, but in this case condensed magnetic field lines) And what field of theory is this called? (Like is it particle physics, or quantum theory?)

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