« first day (1920 days earlier)   

12:21 AM
Wazzap, y'all?
Yo, @FenderLesPaul, what subfield are you interested in?
I can hook you up with some sweet labs, you might say.
 
Hi pal :-)
 
@guest Hi.
 
How are you?
 
@guest Incredibly tired, but pretty good. Very exciting results in the lab.
 
Cool @DanielSank
 
12:29 AM
What are you up to, @guest? @BernardMeurer?
 
I'm reading some stuff on bytes and strings on Python 3 :p
And preparing to go out for some 'aided recovery' of my application denial
 
@BernardMeurer Ah yes indeed.
 
I think FederLesPaul's specialization is quantum gravity.
 
@guest Eek. Well, he ought to meet up with D. Marolf.
 
@guest I'm pretty sure @DanielSank's specialization is pure and applied magics
 
12:31 AM
@BernardMeurer Heh, why do you say that?
 
Because he's kidding :P
 
@DanielSank Because you work with some really amazing stuff that is just magical (in the sense of enchanting and surprising rather than of it being voodoo)
@guest I'm pretty sure it's the chinese that manufacture the Kindle
Dammit, your edit killed the joke
 
:D
It's all good in da hood.
 
By the way, @DanielSank, did that number include area code? I never know
 
@BernardMeurer Yes.
 
12:41 AM
Alrighty, awesome. Maybe I get into UCSB and then me, you, and @FenderLesPaul can be bffs and go for strolls on the plentiful daisy fields as we sing and jump
 
@BernardMeurer Perhaps.
 
I gotta quit reading books to my cousin. They're making my imagination weird
 
How old is your cousin?
 
@BernardMeurer The problem with going for strolls in and around UCSB, is that many of the best walking routes take you past the lagoon or the slough. Either way you might be in for a rather strong odor (depending on the recent weather).
I like to walk so I just got used to it. Used to know all the path around the lagoon and out near campus point. Also where you could scale the cliffs if you (a) had misjudged the tides of (b) the campus police might misconstrue your presence on the beach near a party as "minor in possession".
Not that the latter applies to you, but it applied to me for a while.
 
12:59 AM
@guest five or so
Hahahaha thanks for the tips @dmckee; what about daisy fields tho?
 
Isn't reading to him or her considered home schooling?
 
@BernardMeurer The Chancellor's Lawn sometimes has dandelions. Does that count?
 
 
1 hour later…
2:08 AM
@DanielSank quantum gravity
I'll be working with a person in KITP (ideally Don Marolf)
 
@FenderLesPaul I believe you wanted to ping DS there. (Use the little arrow! :P)
 
Oh oops
my bad
 
2:42 AM
@FenderLesPaul So you're definitely coming here?
 
@DanielSank The only school I'd consider over UCSB is Princeton if I get in
which basically means yeah I am coming there
 
@FenderLesPaul I guess Princeton is a good option because of your subfield?
 
@FenderLesPaul Screw that. Surfing.
 
Haha totally
 
2:54 AM
Friend of mine used to bring a big wheely black board to the beach and do his QFT homework.
Try that in Princeton.
To be straight for a moment - KITP is pretty neat. There are a lot of conferences and people going through there all the time.
If you don't mind I'd like to give you two bits of advice:

1. wherever you go, make sure there is more than one person you'd be interested to work with.

2. Make sure you go somewhere that the students are happy.
By the way, assuming your user name reflects your interests, if you do come here you have to teach me to play rock guitar, and I'll teach you classical.
 
@DanielSank Thanks for the advice! I really appreciate it :)
as for people to work with, yeah that's one reason UCSB was my top choice
 
Yes, item #1 is important.
 
since there are around 4 or 5 people I'd love to work for
 
That's good.
 
mainly Don, Gary Horowitz, Joe Polchinski, and David Bernstein
 
2:59 AM
Good for you. Those are all excellent researchers and nice people.
 
I'm told the students are happy there; a friend of mine who graduated from Cornell 2 years ago is there now working for Joe and loves it
And yeah I would love to teach you rock guitar haha that sounds dope
 
Yeah, UCSB is pretty good on the grad student happiness scale.
 
This sounds dumb, but sunshine really does help.
 
Yeah I'd imagine
 
3:00 AM
Princeton is obviously an awesome department too.
Don't get me wrong.
 
 
3 hours later…
5:49 AM
WAIT
@DanielSank Are you into classical?
 
@BernardMeurer Yes.
That's my favorite piece of music. ^
I haven't played in years though, so I'm pretty terrible at the moment. It's on my todo list to play more and regain my former glory.
 
6:19 AM
@FenderLesPaul Well then, looks like you, me, and @DanielSank will have to meet up in person, since we're all gonna be there ;)
 
 
2 hours later…
7:59 AM
So, would anyone else prefer if we taught radians in school instead of degrees?
 
8:27 AM
@SirCumference: We were taught radians prior to trigonometry ; our book had a dedicated chapter on circular measure problems.
 
Sadly, most kids aren't
My elementary school math teacher didn't know what a radian was...
It blows my mind
 
It was included in our std.x syllabus; it still is.
@SirCumference: WTF!!
 
You're the minority
 
@SirCumference: Nay!!
 
Yay, I'm afraid
I've never met one person who was taught radians before degrees
 
8:30 AM
@SirCumference: Add to the bonus, we were taught centesimal system also ;)
 
In fact, why on Earth are we taught degrees? They're useless and arbitrary
 
@SirCumference: Won't say such but yes much less useful than the radian ...
 
You don't think they're arbitrary?
Let me ask you this: why are there 360 degrees in a circle?
There could have been 480, or 173, or 91004
They're baseless
At least radians have an exact, indisputable definition
 
@SirCumference: why on Earth, are we taught Newtonian Mechanics? They're useless in the long run! We could have learned Hamiltonian Formalism, then Special Relativity ;P
 
Oh boy, you missed a long conversation
I argued against teaching Newtonian mechanics

Newtonian vs Relativistic physics

Jan 29 at 0:01, 1 hour 1 minute total – 213 messages, 8 users, 4 stars

Bookmarked Jan 29 at 1:03 by Sir Cumference

 
8:34 AM
@SirCumference: Jaws dropped!!!
 
So yeah, an hour long conversation...
But I can understand Newtonian mechanics. GR and QFT are too complicated to teach most high school students
And Newtonian mechanics gives good approximations at non-relativistic speeds
 
Yet things like degrees and script handwriting are useless
Why are we teaching this?
 
@SirCumference: even if we are taught, there must be at some point, we need to be taught circular measure and it's good to get this topic included in the syllabi of our country.
 
Degrees?
But why not radians?
They're infinitely better
exaggeration
But you know what I mean
 
8:41 AM
@SirCumference:We are consuming degrees from std.iv days. But at last in std.ix, we got to learn the circular measure; some intricate problems and yeh we excel at it and from that day, we hardly face degree in our curriculum. come to Ind;P
 
I know, but we shouldn't even be teaching degrees
They should just die out
 
@SirCumference: They are indeed arbitrary but can't be useless! If it gets abolished, then so do Imperial system of measures.
 
Imperial is different but isn't necessarily worse
Crap
 
@SirCumference: Yes. Not worse.
 
But degrees are just nonsensical
 
8:43 AM
Worst!!!
 
They have no base
 
Agreed.
 
9:37 AM
@BernardMeurer: Heard Coldplay's Hymn for the Weekend?
 
 
1 hour later…
10:43 AM
@SirCumference: Scientific fact: If you took all the veins from your body and laid them end to end, you would die.
Splendid!! The most interesting fact, I've ever known.
 
 
2 hours later…
12:44 PM
@SirCumference Imperial is necessarily worse
 
1:10 PM
@DavidZ are you around?
Listening to your song now @user36790
 
@BernardMeurer: Imperial sucks!!
 
@BernardMeurer I suppose so
 
@DavidZ If someone is a partner in a company, could one say they are self employed?
 
I have no idea
 
@BernardMeurer: where is our 10yr old 0celo??
 
1:23 PM
@user36790 Banned for the weekend
@DavidZ darn it
 
@BernardMeurer: WTF!! Why?? When???
Okay! no reason
 
@user36790
Why: None of our business, he was doing something wrong
When: A day ago, or so
 
@David Z: Can I ask you a question?
 
@user36790 Never ask that, just ask the question :p
 
...........
 
1:27 PM
@user36790 No. No questions allowed. In fact for asking that one you go directly to jail, do not pass go, do not collect $200 :-P
Seriously though, (1) yes (2) I do agree with Bernard's advice
 
:O
 
Okay, let you take an isolated gas system in a container of volume $V$; $N$ and $E$ are number of particles and energy of the system-both are fixed. During the equilibrium, what would be its entropy?
Of course, equilibrium would be dominated by the macrostate which has the max. multiplicity.....
So, should I write the entropy of the system at equilibrium as $S=\ln \Omega(E,V,N)\;?$
But the fundamental Postulate (ergodic hypothesis) says that all microstates having the same $E$ are equally likely at equilibrium....
 
$S = \ln\Omega$, don't forget the log
sneaky :-P
 
Indeed, it is engraved on his tomb stone :P
 
1:35 PM
So, when the system has all its particles at the left half of the container, that is the macrostate would be $(E,V/2,N)$, then won't the entropy at equilibrium be $S= \ln\Omega (E,V/2,N)\;?$
 
It's not at equilibrium in that state, though.
Or to put it more precisely: in order for a system to be at thermal equilibrium in the macrostate $(E, V/2, N)$, then external conditions should be such that it will stay in that macrostate.
(I think... this is not exactly my specialty)
 
@David Z: Then why is it that the postulate says all microstates having the same energy are equally likely at equilibrium?
 
Not sure I see where you're going with this
 
:(
 
I mean, how does the particles all being in the left half of the container imply that some microstates are more likely than others? (which is what it seems like you're saying)
 
1:47 PM
Okay what does actually the fundamental postulate say?
The microstates, no matter what the volume may be, all have same energy, IMO, are all equiprobable over long time scales.
 
Right...
 
:)
The problem is with the word equilibrium in the postulate....
 
Are you thinking about an infinite time scale?
 
No, finite but greater than the interaction time between the particles.
The system is isolated and all the microstates whether they belong to the macrostate $v/2$ or $V$ all have the same energy and all would occur equally likely....
But since, the macrostate with $V$ has the greatest multiplicity; it would dominate....
 
@BernardMeurer Murica.
 
1:57 PM
Now, won't I call that macrostate $V$ the only equilibrium condition? I thought so, but the postulate tells there can be other microstates which occur at the equilibrium that correspond to macrostate $V/2$; now won't I call the later fluctuation?
 
@user36790 Yes, which reflects the fact that the fraction of the time in which all particles are in the left half of the box is exceedingly small
 
:)
 
Or, wait.
 
:/
 
I just noticed you're talking about macrostates with different volumes. I think that's wrong. The macrostate is always $(E, V, N)$.
Or at least, we represent the system by a macrostate parametrized by $(E, V, N)$.
As long as we do so, the resulting model exhibits thermal equilibrium.
 
2:01 PM
Then you consider the particles confined to the left-corner of the volume of the container $V$?Won't that be $V/2$?
 
If the particles are all in the left half of the box at some particular moment, you can represent the system at that moment by a macrostate parametrized by $(E, V/2, N)$, but the resulting model does not exhibit thermal equilibrium - and in fact is not very useful because it very quickly ceases to be valid.
 
Yes, that corresponds to the macrostate $V/2.$
 
@user36790 Yes, I'm saying that, in the model of a gas in a box of volume $V$, even if all the particles are in the left side of the box at some moment, you should still consider the gas to be in the macrostate $(E, V, N)$
 
Enlightenment!!
 
In a sense, a macrostate represents a whole collection of possible microstates. You can't look at a single microstate (i.e. a single list of positions and velocities) and say "this corresponds to the macrostate X" because a given microstate can be part of many macrostates, depending on how the system is defined.
 
2:06 PM
@DavidZ: You are Buddha!!
Spelling sucks!!!
 
Ah, well, good if it makes sense
Though again, this is not really my area so I'm not 100% sure of all that
 
@ChrisWhite yay!
Yes we must meet up!
 
2:29 PM
@BernardMeurer Also, the imperial system has a base. Yes, that base is the metric system, but it's an imaginable distance. Most children can imagine a foot as actually being an average foot length.
Degrees are not at all helpful. They are so arbitrary that they have no redeeming qualities.
If I ask you to draw one degree on the spot, you probably couldn't.
 
Damn Babylonians
 
@ACuriousMind Wait, was it the Babylonians or the Sumerians?
 
@SirCumference Doesn't matter, both had the sexagesimal system
The Sumerians came earlier, but for some reason the Babylonians are blamed more often for it
 
Oh really?
Love how ya use "blamed" instead of "credited"
Nowadays, everyone's using the decimal system (except for those people who think we'll actually start using base-12)
So there's no use for degrees
 
Stress must also be given on Centesimal system. It has many benefits ...... well none!
@DavidZ: So, a microstate can correspond to more than one macrostate?
 
2:48 PM
Then there's also the pi vs tau argument
 
@user36790 Yeah, I think so. That doesn't mean you should start thinking of a system as being in multiple macrostates at the same time.
 
If we use tau, we can't have things like pi day or $e^{pi*i}=-1$
 
It's not like quantum states.
 
@DavidZ: Gotcha. Let me read a bit...
@DavidZ: To each microstate there corresponds exactly one macrostate. :__O__ Check this pdf: ls.poly.edu/~jbain/physinfocomp/lectures/…
 
3:06 PM
@user36790 This is true if your notion of macrostate is "equilibrium configuration given by energy, temperature, particle number" and you already assume that equilibrium configurations have uniform probabilities for their microstates, since you can compute energy, temperature and particle number for any given microstate.
 
3:16 PM
@ACuriousMind: So, who is correct? David Z or that pdf?
 
@user36790 Both, within their assumptions.
For DavidZ, a macrostate may be a collection of microstates that's not necessarily in equilibrium or uniform, and then you can't associate microstate<->macrostate uniquely.
 
@ACuriousMind: Got it.
@ACuriousMind: Thermal equilibrium doesn't exist at the level of microstates.

Reference https://www.physicsforums.com/threads/meaning-of-equiprobability-principle-in-statistical-mechanics.254543/ Do you believe it?
 
@user36790 Of course. Equilibrium is a statement about the probability distribution over the microstates not changing in time - that doesn't make sense for a single microstate since of course a single microstate changes in time.
 
3:45 PM
@user36790 for a given definition of the system (and its surroundings). That's what the PDF omits. (Rightly so, because it's usually understood)
 
 
3 hours later…
6:25 PM
0
Q: If you play more than one music track at once on a computer, does the sound heard get louder?

zordmanSay you are using a computer and have multiple Youtube videos playing music (or any other video) at the same time, does the sound produced by the computer's speakers (or a pair of headphones) become louder than just playing one video? I.e. does the amplitude of the sound waves from multiple video...

Is this about physics at all?
 
Was wondering
 
@Danu Yes; the physics of out-of-topicness
 
I want to give the question the benefit of the doubt, though. The whole computer stuff could just be their way of saying they are comparing one sound source to two sound sources.
 
The question is essentially: Does my computer produce two separate sound waves when I play two videos?
 
I was ordered a Feynman tips on physics.
 
6:32 PM
@ChrisWhite Like I said in the comment I just wrote, the engineers designed the system to mimic two physical sources when you overlay things, so you could argue it on that basis. But I don't really like it for physics.
 

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