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6:13 PM
Any1 there??
 
nope
 
'the maximum value of D admitting a 32 component spinor is D = 11'?
 
@Pranav Maaayyybeee...
 
@Mithrandir24601 You haven't made any questions on my AMA post, I am heartbroken
 
@BernardoMeurer Me? Question? Since when have I asked a question? :P
 
6:17 PM
You haven't, that's the problem
 
I mean, I'll be here and I'll be interested on what you're going to say, but I'm just terrible at coming up with questions...
 
WELL START THINKING
MR PHD
 
@BernardoMeurer (I don't have a PhD. Yet. Hopefully in a few years)
 
@bolbteppa Yes, if you believe the lore about in which dimensions Majorana spinors exist :P
 
Well, ask a question and you get a PhD
 
6:20 PM
I spend all day thinking. Why do I have to think now that I've got home?
2
 
from Bernardo University
Very prestigious
 
@ACuriousMind, you beat me to it on commenting on this by seconds =P
 
More selective than Harvard, literally no one gets in
 
@heather The power of autocomments :)
 
should be made a duplicate of ?
@ACuriousMind I am getting that script now. why have i never heard of that?
 
6:23 PM
@heather Technically, Weyl spinors are a proper subset of spinors, so that would be like making a duplicate of
 
@ACuriousMind right, but it's more about size. weyl spinors has 1 question, spinors has 88 - they're both fairly diminutive.
 
I do think it's debatable whether Weyl spinors in themselves are large enough a topic to warrant their own tag and could not just be tagged 'spinors', though
 
Oh my god justifying this looks terrifying
 
@heather Is the actor who played Data in TNG a subset of spinors?
 
@ACuriousMind that's what i mean, i thought synonym might be appropriate in that case.
 
6:24 PM
Meh, I'd avoid the loss of information and leave [weyl-spinors] there
 
@Giskard42 what is "TNG"?
 
Sorry. Brent Spinor joke.
 
@heather Oh, it just has one question? I'd just swap out the tag for 'spinors' then on that question and let the system remove the weyl-spinor tag on its own.
 
@ACuriousMind ah, okay.
 
@heather The Next Generation, the second Star Trek series
 
6:25 PM
@ACuriousMind done
 
There are questions on Weyl spinors that are tagged (and not ) though
 
@heather I don't know why it's so relatively unknown, but it's massively useful
 
has four questions.
and there exists a tag that has 392
 
Hi @0celo
Who suspended you and why and when?
 
@Mostafa Shog9 did
Because 0celo7 said something that is perfectly fine
 
6:29 PM
@Mostafa suspended for saying "JEEhad" too much and trying to ask why it was a problem, Shog9 suspended him, and he got suspended maybe...a month ago? (@Bernardo is that last right?)
 
but then some mod from RPG went bananas or something
@heather Yeah
 
@heather Affine Lie algebras are technically Lie algebras, but they are not what people imagine under a "typical" example of a Lie algebra. That tag carries more information than 'Weyl spinor' did, I'd just leave it alone
 
@Bernardo that was a different thing (RPG) wasn't it? that meta chat conversation with DS that never got resolved with SevenSidedDie?
@ACuriousMind okay.
 
@heather What is "JEEhad"?!
JEE exam?
 
yeah
 
6:30 PM
And it seems this needs to be your periodic reminder that we do not discuss suspensions of users while they are still suspended.
 
@heather Yeah, that guy
 
At least not in chat where they cannot respond
 
@ACuriousMind i honestly don't understand that rule, but alright.
 
@heather Ah okay then
You know, some people are simply too smart to survive in the human society...Ron Maimon being one example.
(he is suspended on every online community I'm aware of)
 
perhaps that's not a sign of being too smart, but of being not at all socially aware, which is the opposite of one kind of "smart" (don't know anything about Ron Maimon)
besides, isn't he still around on Physics Overflow...?
 
6:36 PM
@heather PhysicsOverflow is a community built for those suspended here so I can't really accept that as a counterexample to my statement above
 
@heather y'know, this is why I ask y'all not to speculate.
 
@Mostafa you said "every online community" - physics overflow is an online community, yeah?
 
::hides::
 
You: Why did he get suspended?
Me: I don't think it's useful to discuss that here, he can discuss it with me if he wishes.
Y'all: must've been "JEEhad" - clearly this is a dark magic word
Also y'all: there's objectively nothing wrong with saying "JEEhad"; since we've now established that was the reason, we can declare the suspension bogus.
Me: ...
 
@Shog9 i read through the transcript and was there for part of the conversation. while that may be oversimplified a bit, it's the swift summary.
 
6:37 PM
@heather it's also entirely wrong.
 
um....let's see, what else happened...he spent to long discussing with you instead of just stopping and never using the word again?
 
@Shog9 We're damn tired of y'all suspending people and then avoiding questions like Neo
 
@Shog9 i don't believe that's exactly what happened...
 
@heather I have zero interest in whether y'all use or do not use "JEEhad" to refer to your disagreements over some schoolwork.
@BernardoMeurer I'm damn tired of folks here taking what should be a calm discussion over some little disagreement or policy, and egging folks on until they're all worked up over it.
11
A: Should discussions on topics which disturb long time users of the chat room be banned?

Shog9You left out a lot of context; I'm tempted to think you're just cherry-picking bits of that conversation to make others look bad while ignoring your own behavior and how it contributed to the situation. Here's something I would consider a really critical bit of context: (for casual readers: "...

 
@Shog9 THEN LETS HAVE A CALM DISCUSSION
 
6:41 PM
@Shog9 i'm darn tired of mods taking things a bit more aggressively than they should.
you're the one who just escalated this discussion, for goodness sake.
 
in Physics Meta, May 18 at 22:47, by Shog9
@BernardoMeurer if @0celouvskyopoulo7 wants to talk about it, he can find me in the tavern. No one else's business.
@heather you both asked me at the time of the suspension and I stepped in to address it.
You didn't like the answer I gave; fair enough. That doesn't give you license to make stuff up
 
@Shog9 and gave no real answer. i didn't make anything up (that's kind of offensive, honestly) - i made a fairly logical conclusion that many other people in this chat made.
if it was just me making that conclusion, fine.
 
15 mins ago, by heather
@Mostafa suspended for saying "JEEhad" too much and trying to ask why it was a problem, Shog9 suspended him, and he got suspended maybe...a month ago? (@Bernardo is that last right?)
 
...and?
 
Why is it that when I want to fight no one wants to fight me, but today when I want to chill everyone wants to fight
 
6:45 PM
@heather and you're spreading misinformation.
Stop.
 
@Shog9 well, first off, i'm not the only one who says that, and second off, it's basically the logical conclusion - he said something you didn't like, he disagreed with your assessment, he discussed it with you, and it ended in him being banned. i read the darn transcript, and was there.
please, don't be taking this so harshly.
 
@Shog9 Yeah, now I really believe @0celou is suspended for saying the word "JEEHAD".
 
:shrug:
@heather I wasn't even in the room, so I don't know what you're looking at.
 
@Shog9 erm...yeah you were in the room, the ArtOfCode was doing the talking
> That's not what I've said. I said someone found the comparison offensive, no matter how it was meant, so you stop using it - art of code
 
@heather It's misinformation when you say that he was suspended "for" that - it's a classic post hoc ergo propter hoc. Lengthy suspensions are rarely based on one specific incident, but on a pattern of behaviour. And we do not want to publicly drag out these patterns - effectively "shaming" them far beyond the length of their suspension - unless the suspended user themselves asks for that.
 
6:50 PM
okay, what, do you want me to say " suspended for saying "JEEhad" too much and trying to ask why it was a problem along with previous incidents"?
 
@0celouvskyopoulo7 Just texted me, verbatim, "Let ACM know I see nothing shameful about these events"
 
@BernardoMeurer I pretty much expected that, but point is, if he wants to have this discussion, Shog already invited him to the Tavern. There's no point in having that conversation here, and without him.
 
@BernardoMeurer How can we be sure you're not lying and @0celouvskyopoulo7 really said that? Give us a proof.
 
@ACuriousMind, isn't there, though?
 
Ryan just texted me a picture of a talk at the Tavern with Shog
 
6:54 PM
there's plenty of point. a suspension that seems arbitrary should be explained. that's that.
 

 Tavern on the Meta

MY GOD, IT'S FULL OF STARS AND BACKLOG! General friendly chit-...
The conversation they recently had
 
oh gosh
@Shog9 really? That was the most unclear statement ever.
okay, not ever.
but really, it was unclear.
> You have an unfortunate tendency to pour gasoline on a fire when you see one; if you can avoid that, it'd make handling the little disagreements that crop up in the h-bar a lot easier.
so first, you call it a "little disagreement" - so not really a large incident.
second, this "pour[ing] gasoline on a fire" - what, was that discussing it with the mods in the room at the time and trying to understand why it was a problem?
> not helping resolve the situation, getting in the way of folks that were.
 
Goddamit I just glued my fingers together with superglue
And not my fingerprint scanners also won't work
 
as I read the transcript, 0celo was talking with the mods trying to understand the problem. if that's not "helping resolve the situation" i dunno what is.
 
@BernardoMeurer ...how are you typing, then?
 
7:00 PM
> we've talked about this before - shog9
> Sorry, I honestly don't recall ever talking to you. - 0celo
 
I can type without my thumb and index
 
> :shrug:
would it have been so hard to provide a link?
 
It's actually really easy
 
@BernardoMeurer Immerse bonded areas in warm, soapy water. Peel or roll skin apart; a spatula or teaspoon handle or even a pencil will help. Remove cured adhesive with warm, soapy water (may take several applications). Fingernail polish remover with an acetone base has also been successful for removal of cured adhesive from skin. (from here )
 
so...i still stand by my original comment and i'm not really sure how "misinformation" comes into this, and i'm also not sure how trying to understand your reasoning is the same as being "addicted to drama" @Shog9
 
7:06 PM
@Mostafa I'm scraping it off with a scalpel I found
 
@heather I've designed an experiment to see if that word really caused his suspension: Someone says it many times and see if he gets suspended.
 
@Mostafa yep, that person will be, if only for spamming the chat.
i think i'll avoid being the guinea pig on that one.
 
Okay I'm going to try it because I don't care to get banned for a couple of days.
I'll say it infinitely many times to be sure.
 
@Mostafa I wouldn't. that's not a real test anyway.
besides, what's the point?
 
We should break MathJax again and show him who's boss
4
 
7:08 PM
@Bernardo that was awesome
i need to find the transcript for that =P
 
@BernardoMeurer Careful, don't scrape off your fingers :P
Also, why do you have a scalpel lying around?
 
@ACuriousMind Don't worry, it's really rusty and not cutting well
I have more blades though
I thought I could eventually need it
 
@heather Ok, I'll make this really simple & put all the relevant information in one place:
@0celouvskyopoulo7, you're one of the most-flagged, most-suspended users on this entire chat. Like, top-5 all-time. Even calculated as a ratio of suspensions per message posted, you're near the top of the list.
You can explain away the odd misunderstood comment here and there, but this is long past that point. Either your preferred mode of operation here is intentional trolling, or you simply have zero interest in not causing problems and thus put no effort into avoiding issues even when they're pointed out to you, repeatedly.
So here's what's gonna happen, what has already started happening starting, oh, on about 6 months ago, and what you should expect in the future: if you're involved in a discussion and it goes south faster because of your involvement, you're gonna lose access to chat for increasingly long periods of time. If you get flagged, same deal. You have years of past experience here that by all appearances you haven't learned from - either learn from 'em now, or go somewhere else.
 
"Don't worry, the scalpel is rusty!" is not a sentence I expected to hear.
 
@0celouvskyopoulo7 Damn, congrats!
@ACuriousMind You can always count on me for that :P
 
rob
7:10 PM
@BernardoMeurer That's the kind of thing that should make you wonder whether your tetanus vaccination is current
 
@Shog9 fair enough.
thank you for being clear about this.
that's all you needed to say.
 
@rob My tetanus vaccine went stopped working c. 2014
 
@heather I've said it all before. In this room.
 
I have yellow fever vaccine until 2024 though, does that help?
 
Give it another couple weeks and y'all will be asking me the same questions again, like I've never been here before.
 
7:12 PM
@BernardoMeurer Yes, it means you won't get any yellow fever from the rusty scalpel.
 
@ACuriousMind See that, responsability!
@Shog9 Who are you?
 
Okay, so do you think I still have to perform that experiment?
 
And what happened to 0celo7
 
lol
 
@BernardoMeurer I'm starting to think these organ harvesting jokes had some ring of truth to them :P
 
7:16 PM
@ACuriousMind It's more a field than a ring really
 
rob
@BernardoMeurer A field of truth?
 
@rob Yeah, #algebrajokes ?
 
@BernardoMeurer ::groan::
 
@Shog9 you are wrong about everything! who are you again?
 
rob
@BernardoMeurer I see that your wit is as sharp as your scalpel
 
7:18 PM
@rob :(
Wait
JOKE'S ON YOU I JUST CHANGED THE BLADE
AHA!
 
rob
Finally, some fresh humor
 
Actually, when I tried proving that boolean logic forms a field I failed
so I guess there can't be a field of truth
Even if you allow for special operators like XOR, NOR, XNOR
It failed on.... Let me see my notes
Every element $x$ of $F$ except 0 is invertible for $\cdot$
It's not true for a boolean algebra IIRC
So, no field of truth :)
@ACuriousMind Verify pls
 
rob
@BernardoMeurer Why isn't that true? $1\cdot 1 = 1$, truth is its own multiplicative inverse.
 
I don't know, My notes had a "?" there
 
@BernardoMeurer The smallest Boolean algebra is isomorphic to the field with two elements.
But no larger Boolean algebra is necessarily a field.
 
7:26 PM
From when I tried this
Look at 3.
I think my table is wrong
Because I remember being convinced a boolean algebra formed a field
 
We discussed this before:
Sep 28 '16 at 0:28, by ACuriousMind
Well, the two-element Boolean algebra is clearly a field
 
Riiiiight!
But as far as I enforce the algebra having 2 elements I'm safe
 
@BernardoMeurer *responsibility
 
@EmilioPisanty Hey! a scott manley fan? here?
 
user228700
7:35 PM
Oh hi there, @Sir! :-) How's it going?
 
@Giskard42 sure, what about it? =)
 
@ACuriousMind Can you look at line 85 of this TeX file github.com/bemeurer/boolean-vector-space/blob/master/…
 
I can, but I don't actually know how tabular works
 
How could I add a vertical line on that table to separate the elements $a, b$ from the operators
Ah
Darn
 
I usually use some package like tabularx, where the vertical line would be as easy as writing cc|cc
I'm not sure that works with plain tabular, but you could try it
 
rob
7:40 PM
@ACuriousMind That's the way.
 
That yields something horrific like this
 
rob
@BernardoMeurer That's not my experience. Let me poke around.
@BernardoMeurer What happens if you get rid of the redundant lightweight horizontal lines? Do the vertical lines join up in that case?
 
Aha! Yes
But this still doesn't look very nice I think :/
How would y'all do this in a nice-looking way?
 
rob
I think I just use \hline rather than \toprule and friends.
 
@Kaumudi.H Good, you? :)
 
7:45 PM
@rob Aha! That does look nice!
 
I'm trying to find time to go on the chat
 
rob
@BernardoMeurer You only need the horizontal line between the header and the data, anyway.
 
@rob yep
 
@Mithrandir24601 Hey
 
@JohnDoe Hi
 
7:57 PM
@Mithrandir24601 Sorry to summon you for something trivial...Are you famaliar with the fundamental theorem of quantum measurment?
@Mithrandir24601 It states that every set of operators $A_n$ satisfying $\sum_{n}A^{\dagger}_nA_n = I$ describes a possible measurement
 
@JohnDoe 'Summon me for something trivial' I'm here anyway, so it's not like I mind :P
@JohnDoe Kraus operators?
I've had lectures that involve Kraus operators, but it's not like I know a lot (or even very much) about them
 
@Mithrandir24601 I think so, yeah, but it's not really named in this text, they do mention that...So we get density matrix $\tilde{\rho} = \frac{A_n \rho A_{n}^{\dagger}}{p_n}$
after measurement.
 
@JohnDoe What is your definition of "measurement" that that's a "theorem", and not a definition?
 
@ACuriousMind I don;t know the rigorous one but for this purpose it is just the operator that define the change on initial density operator $\rho$ to $\tilde{\rho}$. It could be taken as a definition I guess, there is a motivation which precedes it...but not a direct proof...just a motivation.
@Mithrandir24601 From the decomposition theorem we can write these measurment operators $A_n = U_n \mathcal{P_n}$
@ACuriousMind How to I get latex to render on my chat?
 
8:05 PM
Look in the upper right corner of the chat room.
 
@JohnDoe I take it that $U_n$ are unitaries and $\mathcal{P}_n$ are just arbitrary matrices? Or are they Paulis?
 
@ACuriousMind :O I've never looked closely at that...
 
@Mithrandir24601 I would assume that's polar decomposition that the $P_n$ are positive-semidefinite Hermitian.
 
@Mithrandir24601 Yeah but $\mathcal{P}_n$ are positive matrix. Like here.
 
@ACuriousMind Ah, OK. Makes sense, thanks
 
8:07 PM
@ACuriousMind Yeah exactly
@Mithrandir24601 We can then write the density matrix after the measurment as $\tilde{\rho_n} = U_n(\frac{\mathcal{P}_n \rho \mathcal{P}_n}{p_n})U^{\dagger}_n$
 
@JohnDoe You forgot a dagger on one of your $\mathcal{P}_n$s :P but yeah
 
@Mithrandir24601 It is assmued Hermitian as Acurious said.
 
Ah, they're hermitian :P My bad
 
@Mithrandir24601 Yeah. Can you see why the unitary operators $U$ play no role in extracting information by measurment.
@ACuriousMind It does not change the eigenvalues of any operator $A$ where $UAU^{\dagger}$? Is that what you mean?
 
Let me ask first what "play no role in extracting information by measurement" actually means :P
 
8:17 PM
@JohnDoe This might be a bit of a roundabout way, but a Kraus operator is equivalent to a quantum channel. Acting on said channel by a unitary gives you the same channel, hence acting on a Kraus operator by a Unitary is the same Kraus operator (Kraus operators, by the way, aren't unique)
 
@ACuriousMind That's a direct quote, not my quote, I suspect it means that the eigenvalues don't change, hence ...Am I right about the unitary operator?
 
Blegh, I'm messing up words a bit - A quantum channel can be represented by Kraus operators is a better way of putting it
 
@Mithrandir24601 Is a quantum channel a density operator?
 
Not that it matters, because you can directly show this using Kraus operators...
 
@BernardoMeurer Do you have any experience unlocking a modem that is locked to an operator?
I have a Huawei USB 4G modem that is locked to some mobile operator but I want to use it with another sim card from another operator.
 
8:21 PM
@JohnDoe Well, sure the unitary doesn't change eigenvalues. But I really mean that it's not very clear what "extracting information by measurement" is supposed to mean specifically.
 
@JohnDoe No, but it maps density operators to other density operators
 
@Mostafa No, all I know about anything remotely like this is that unlocking locked iPhones involves something called an IMEI code and a fee to a third party service
Give me the exact model of the modem and I can try and find something
 
@Mithrandir24601 So it's the measurments bassically? so $\rho \to \frac{A_n \rho A_n^{\dagger}}{p_n}$ would be a quantum channel.
@ACuriousMind They don't change the eigenvalues of any operator when written as $U A U^{\dagger}$?
 
Yeah they should be normally unlocked using the IMEI code (some websites give the unlock code given the IMEI)
But this model uses a different algorithm.
@BernardoMeurer Model is E3372h-153
Their S/N starts with G4PD
 
8:27 PM
@JohnDoe So the channel is $\xi\left(\rho\right) = \sum_n A_n\rho A_n^{\dagger}$
 
@Mithrandir24601 Oh okay understood
 
@BernardoMeurer There are many websites like that. They only get some information that the tool generates (hashes, etc.) and send you the unlock code after you pay.
 
@Mostafa I really know nothing about this stuff, I'm sorry, I wish I could help
If you can get me the firmware in binary I can hexdump it and see
Maybe It's simple
 
It must be simple because there are many websites, blogs, forums,... that are doing it.
@BernardoMeurer What??
firmware version is 22.001.26.02.03
 
i just took a practice ACT science exam on the act website
 
8:40 PM
@JohnDoe i.e. $\xi\left(\rho\right) = \sum_{n, m, l} U_{n, m}\mathcal{P}_m\rho \mathcal{P}_l^{\dagger} U_{n, l}^* = \sum_n\mathcal{P}_n\rho\mathcal{P}_n^{\dagger} = \sum_n p_n \bar{\rho}$, so it's the same channel, so acting on a channel by any unitary doesn't change the channel, so there's nothing you can learn from that
 
it wasn't really that bad, surprisingly - i was expecting it to have you know facts off the top of your head; instead it gave you passages to read. it was more thinking/reading than science.
 
@heather How did it go?
I only ever took the SAT
 
@Bernardo I got a 33/36 on that section (i think; i only got three wrong, and i assume they had 36 questions on the test)
 
@heather Hey, nice!
 
@Mithrandir24601
So in a sense the channel $\xi\left(\rho\right) = \sum_n A_n\rho A_n^{\dagger}$ is averaging the outcomes for a particular measurement? Since $\sum_n p_n \tilde{\rho}_n = \sum_{n} A_n \rho A^{\dagger}_n$.
 
8:42 PM
Start doing SAT tests regularly
The SAT is a test of instinct pretty much
 
@Bernardo I was probably just lucky, I doubt the test is actually like that.
 
These tests aren't hard heather
 
@BernardoMeurer Iowa State prefers the ACT, so.
 
Ah
You're focusing on Iowa State?
 
yeah
for undergrad, anyway. my dad wants me to, and i want to, so.
 
8:43 PM
Hm
 
it's also cheaper because it's in-state =)
and it's got a great engineering/science program.
 
Thanks anyways
(I personally hate it when someone asks something that has no idea about; like myself now :)
 
@heather So does Stanford, UC Berkeley, Harvard, Cornell, ...
You have potential
 
@Bernardo eh, my dad says colleges like that are better if i want to go to grad school.
 
@Mostafa Sorry for not being more able to help, without hardware on hand and a logic analyzer I can't do much :/
 
8:45 PM
i mean, for grad school, not for both undergrad and grad.
 
::shrugs::
 
@JohnDoe I'm not sure if 'averaging' is the right word, but you act with the measurement projector on the state/density matrix and get a sum of possible outcomes, weighted by the probability of getting that outcome. Neither the possible outcomes, or the probability of these outcomes changes when acted on by a unitary
 
@BernardoMeurer basically, yeah. my dad also says I'll be sure to get in and will be able to get more opportunities than in a bigger school, he says it's being a "big fish in a little pond"
 
@heather Just don't limit yourself, try Iowa state, and also some badass big-name schools
 
@Mithrandir24601 Why not mathematically though? Why does it not change I mean after acted on by a unitary operator.
 
8:46 PM
That's a good argument
 
also, the one time i suggested applying to other schools, like MIT or whatever, my dad got kind of upset.
 
@heather I'll hit you on hangouts
One sec
 
okay
 
@JohnDoe Is this what you mean?
 
@Mithrandir24601 Does it make sense that after measurement we can write $\tilde{\rho} = U_n(\frac{\mathcal{P}_n \rho \mathcal{P}_n}{p_n})U^{\dagger}_n$, where since they $U$ does not change the eigenvalues of $\rho$ is also does not change the eigenvalues of $\mathcal{P_n} \rho \mathcal{P}_n$ and hence does not play significant role?
 
8:56 PM
@heather Parents can be like that... There is an argument with the whole big fish/little pond over little fish/big pond. But if you want to go to the likes of MIT as a grad, you're going to have to be a little fish someday. Also, they're probably going to have better teaching than a little pond, so you're going to be better at physics there than compared with said small pond. It'd be unbelievably tough though
@JohnDoe Hang on... I've just noticed something - what do you mean by $U_n$?
 
@Mithrandir24601 rytsas, by the way
 
@heather Rytsas
@JohnDoe As in, what does the 'n' labelling mean?
 
@Mithrandir24601 The unitary operator which corresponds to the measurement operator $A_n$ which we get from the polar decomposition $A_n = U_n \mathcal{P}_n$.
@Mithrandir24601 $n$ is the outcome of the measurement which corresponds to some measurement operator $A_n$ I think.
 
@JohnDoe OK. It's just that this is slightly different to the way I've notated it...
@JohnDoe Do you mean $A_n = \sum_m U_{n, m}\mathcal{P}_m$, or something else?
 
@Mithrandir24601 Just $A_n = U_n \mathcal{P}_n$ just decomposing $A_n$ as in the first sentence of...
@Mithrandir24601 Yo see this.
@Mithrandir24601 this I meant sorry...
 
9:09 PM
@JohnDoe 404 :/
Ah, got it :)
 
@Mithrandir24601 Well I think $U A U^{\dagger}$ is a change of basis with the same eigenvalues...
@Mithrandir24601 I think the idea is that the unitary operators hence does not change the uncertainty of the system just the states it is most likely to be found in.
 
@JohnDoe If it works and you can make sense of it, it's definitely better that my (as per usual) convoluted method :P
 
@Mithrandir24601 That's what you were saying I think.
@Mithrandir24601 I have a headache now, I had whisky earlier, through no fault of my own and now trying to do physics, not a good idea...
 
@JohnDoe I've had a good, hard day of work, so my brain's not functioning properly either :P I wouldn't complain if I had some whisky either
 
@Mithrandir24601 Apparently it's a good idea.
 
9:15 PM
Yeah... ::goes and pours some port::
 
@Mithrandir24601 :) Have a good night, going home now
 
@JohnDoe You too! Hope I haven't been too confusing. I've been confusing myself...
 
@Mithrandir24601 Nah not at all. I don't have a good grasp on the subject yet, so I'm just feeling my way through. But it's interesting, starting to make a bit of sense...
 
Notation question: what does $\int d^n x$ mean?
Context: The quadrupole tensor with TT-gauge is given by $Q^{\mu \nu}_{TT} = \int d^3 x \rho (x^{\mu} x^{\nu} -\dfrac{1}{3}\delta^{\mu \nu} r^2)$
 
9:38 PM
@Lozansky $\mathrm{d}^n x$ is a shortcut notation for $\mathrm{d}x_1\dots\mathrm{d}x_n$, i.e. an n-dimensional integral.
 
So probably $d^3x$ is a volume element
 
@JohnDoe Sorry, I've just realised that I have been mistaking your labelling (my bad!), so the bit about the Kraus operators being the same as each other isn't (necessarily) true. It is true that it doesn't change the probabilities, 'just the states it is most likely to be found in' indeed :)
 
Can someone ELI5 Christoffel symbols?
 
10:28 PM
Hey, maybe someone can help me out as my search attempts have been failing me. I'm looking for a peer reviewed paper or something of the sort that tabulates the dielectric constant/relative permittivity of III-V semiconductors, specifically InAs and InSb. I'm interested in DC/low frequency values, and also low temperature. All I can find are websites that have tables with no citations.
 
 
1 hour later…
11:37 PM
@heather FWIW I think there might be some truth in there, but one has to be careful. If you want to get into grad school and do well there, it's important to (1) get good research experience as an undergrad and (2) take challenging classes. (And some other stuff) If you go to a top university for your bachelor's degree, assuming you graduate from that university, you're pretty much guaranteed to fulfill both of those requirements.
But if you go to an average university, it can be hard to tell in advance whether you'll have the chance to do so. I know there are major state schools where you can come out well prepared for a top grad program, e.g. Penn State does a decent job of this. I don't know about Iowa State.
Of course I will say that if you want to pursue a career in physics research, where you get your PhD does matter far more than where you get your bachelor's degree.
 
@DavidZ hmm, okay, i'll keep that in mind. Iowa State seems to have a decent number of research opportunities and a wide variety of classes. I could always do a few years there for the required classes/basic stuff found at any university and then transfer (if necessary).
 
Yeah, though do keep in mind where you'd be transferring to.
 
what do you mean?
 
I mean, I'd suggest identifying a few likely transfer "targets" - places you might want to transfer to - and doing a bit of research on what their requirements for transfer applicants are, as well as how the curriculum at Iowa State (or wherever you'd be going first) transitions into the curriculum at the transfer school. That way you'd know if, say, it's unlikely you'd make it in as a transfer student, or if you'd be coming in a year behind and have to delay your graduation.
That's all hypothetical, of course; the point is, transferring introduces additional complications to your education, and I wouldn't just assume that you can jump from one school to another and pick up right where you left off without doing a bit of checking to see that it's a plausible thing to do.
Otherwise you could find yourself stuck in your original school without having an option to transfer.
 
11:58 PM
that makes sense, okay.
how could i figure out if iowa state has the appropriate level of classes, research opportunities, etc?
 
What do you call a quantity such as $\dot{T}/T$ where $T$ is the period of something?
The relative time derivative of the period?
 

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