Statistical Mechanics Lecture 8

[@mashahomya6565]

35:53 magnets 39:53 - 42:34 questions 43:13 simple magnet model (№I with NO interaction between magnets, with external field) 46:55 general case. finding z and average energy E 56:46 m magnetisation defiition 59:53 - 1:06:48 questions 1:06:50 average energy E from z 1:13:24 magnetisation 1:15:00 1d ising model model (№II WITH interaction between magnets and no external field) 1:15:00 a bit of history 1:16:15 model discription 1:24:42 on symmetry

[@Spectacurl]

Thank so bad... I hate that guy who keeps doing not important questions

[@vivekpanchal3338]

Thank you brother 😊

[@Unidentifying]

Thank you Stanford, Susskind, Internet, KZbin and myself for watching. Keep spreading the information and awesomesauce.

[@live4Cha]

Poincare: 29 April 1854 - 17 July 1912 Boltzmann: February 20, 1844 - September 5, 1906

[@sylarfeet]

Thank you Stanford University for all your wisdom and creativeness and your team of world class professionals professors that made it all come true. The answer is @nano second…..

[@joabrosenberg2961]

Poincare recurrences; Boltzman head appears in the room 28:00

[@KipIngram]

26:21 - Well, what that tells us is that our solar system didn't just appear as an eventual result of random motion. There were organizing forces - gravity made it so all it took was a slight deviation from uniformity and from there there was a force urging the particles on toward each other. Fusion lit the sun up, etc. etc. etc. No way it was just dust wandering around. "Luck" gave us only the first nudge, and then other aspects of physics took it from there.

[@FarFromEquilibrium]

@ 14:50 that is the most interesting q&a I've ever heard in one of his classes.

[@KipIngram]

30:00-ish - I love how we get to hear the questions, and Susskind's answer to them. But on some occasions someone take the whole discussion off into left field, and Susskind is too nice to cut them off. Those bits should be edited out; they don't really contribute anything.

[@nurlatifahmohdnor8939]

570 miles = 920 kilometers 1996 Lastime I took KHB for PMR. Because we were a girls school, it was ERT. Boys school was different type of KHB. E-ko-no-mi Ru-mah Tang-ga

[@nurlatifahmohdnor8939]

I India 6, 7 Indonesia 6, 7, 10, 12, 72 73 Iran 6 Iraq 6 Irian Jaya 7 INTERLAT 22 3 INTELSAT 1 MEASAT 1 PALAPA

[@sonjak8265]

Ludwig Boltzmann (20 February 1844 - 5 September 1906); Jules Henri Poincaré (29 April 1854 - 17 July 1912)

[@millennia]

I want to be a professor like him. :)

[@jhs7567]

Sudden disco at 41:12

[@Rayquesto]

This needs to be a meme with a Flamingosis song.

[@KipIngram]

18:25 - He's right - it DOESN'T MATTER. Say the units were Planck Time - 10^-43 seconds. So the time in seconds would then be (2^(10^30))*(10^-43). Take the base 2 log; we get 10^30 + log2(10^-43) = 10^30 - 43*log2(10) = 10^30 - 43*3.32 = 10^30 - 142.84 = pretty much 10^30. So it truly doesn't matter - the questioner just doesn't grok the vastness of 2^(10^30).

[@atrumluminarium]

Can anyone explain what is meant by symmetry and the breaking of symmetry? I really am struggling with that concept :(

[@qwadratix]

+atrumluminarium Symmetry to a physicist means something rather more general than the common idea of 'mirror symmetry'. It means any circumstance where something doesn't change when you vary fundamental parameter like position, time or phase. For example: translation symmetry means that if you perform an experiment, then repeat it half-a-mile down the road, you will get the same result. Time symmetry means that if you perform an experiment, then repeat it half-an-hour later, you will get the same result. Breaking a symmetry means that you find something is different and the experiment doesn't give the usual invariance. For example, if the experiment consisted of measuring the speed of a skateboard, that might be different on another hill half-a-mile away - so the translation symmetry is broken.

[@atrumluminarium]

+Verruca thank you for the help, very well explained. :)

[@Yogesh-rg1if]

For more details about symmetry you can read 4th chapter of the book “the character of physical law” by RP Feynman.

[@petergreen5337]

❤Thank you very much Professor and class

[@sp00n1na70r]

The idea of a body so massive that even light could not escape was first put forward by geologist John Michell, in 1783. The first person to interpret evidence and infer the presence of dark matter was Dutch astronomer Jan Oort, a pioneer in radio astronomy, in 1932. Neither of these things are attributed to Leonard Susskind, both became interesting areas of study before he was even born. And even string theory the thing he is most associated with started with Heisenburg in 1943, Susskind was 6.

[@_HJ_K]

The guy asked the question at 26:14 really seems to lead the lecture off the track. This pal had been in Professor Susskind's lecture since the first class of Classical Mechanics, and had always been very active in the lectures. He might be a very active thinker, which is a good thing. But truly it was a bit waste of time. Well, I don't think we should blame anyone for their overflowing curiosity. But I have to admit that he could just had saved those strange questions for later, make it a discussion during office hour or something.

[@PHYTOGREG]

Susskind is wrong at 26:15 min - the audience member is correct. Susskind supposes that random and independent fluctuations occur over time which determine the probability that a Boltzmann brain (A) pops into existence as (a very small) p. Then he says the 'conditional probability' (his words) that a second Boltzmann brain (B) pops into existence is vastly smaller. This is incorrect. If A and B are independent, then the conditional probability P(A|B) = P(A) = p, i.e. seeing a second brain given that you observed the first is equal to the probability of observing the first. Susskind meant to refer to the joint probability of straight-up observing two independent events (which for indpendent events is P(A)P(B)=p^2), which is vastly smaller. The audience member points this out correctly.

[@thomasmoore8637]

PHYTOGREG Susskind may have used a bad phrase (conditional probability is smaller) but he'd agree with you that P(B|A) = P(A). What he was intending (and what I thought he communicated) was that P(A and B) is far smaller than P(A), and so P(A and not B) is much much much more likely that P(A and B)

[@happytouch7104]

Susskind can NOT be wrong :)

[@thegooddoctorhimself2458]

The audience member has never been correct in this series. Susskind explained it perfectly, as usual. The only thing that could make these lectures better would be to remove the questions from idiots in the audience.

[@internetzpotato383]

His prolonged questioning to emphasize that he caught Susskind in a minor error, and your extended comment, are examples of how someone can be correct and yet waste everyone's time.

[@PHYTOGREG]

@@internetzpotato383 The irony of pointing out a waste of time is that the mere act wastes more time!

[@anklexpress]

I wonder if Neitzsche got his eternal return idea from the Poincare recurrence...I could look this up I guess but I am not

[@LuukVanEgeraat]

I was looking forward to the next video in the series, thanks!

[@blanamaxima]

life is like little Eddys.. like that a lot.

[@abdurrezzakefe5308]

regarding the coherent wife story; if we wait way way way longer, say infinitely long, is it ok to say that some version of us in the future will have a coherent surrounding?

[@nurlatifahmohdnor8939]

My son reminded me that lastime he asked me why the ruler is so shaped? He said that I said it is a watermelon-shape of ruler. I did not tell him it is a protractor. Primary school boy aged 12 he was at that time.

[@rupayansaha721]

1:15:30

[@KipIngram]

20:20 - Do we REALLY KNOW that the universe started out in one corner of the phase space? We just run our equations backwards, and we think they tell us that. But for all we know it started at 50% of that far back, or 40% or 60%, or 99.9%, We don't really know, do we?

[@gulgaffel]

Sounds like last tuesdayism. We don't know and can't know, its something for philosophers to think about(who summons Occam's razor)

[@KipIngram]

53:35 - That particular guy in the class is annoying.

[@남준황-q1m]

Exid의 위아래 가 맞을거야 고모가 맘속으로 흔들라고 생각하고 부르면 그렇게 부르는것일거야

[@ShakeSpear1949]

That depends on your definition of religion.

[@HETHuzhou]

Superb!

[@leonardromano1491]

"If I flip a coin enough times, I will get a million heads in row." Well that does not necessarily have anything to do with coins. hehe

[@MATHEKANAL]

While i absolutly love Lennies lectures, i feel that beginnig in the discussion of the second law in lecture seven and continuing here the level of rigour is declining. Its a little bit more like scientific american

[@nurlatifahmohdnor8939]

Page 61 J. M. Murray

[@sp00n1na70r]

I am just saying that saying Leonard Susskind, in your words discovered/dreamed it/hem up, is ignorant.

[@alirezasadeghifar3815]

Too many questions are asked, makes you lose track of what is being taught!

[@anklexpress]

I love a lot of the questions, but the constant interruptions mid-derivation are insane. I want to be able to listen to the logic of how to derive these things but there are so many derails. No undergrad or grad class ive ever taken would a professor allow this sort of shenanigans. A lot of the times if they just kept silent, their questions would be answered at the next step or two in the derivation. Let the man cook and then judge the soup at the end, not when its half cooked. "We start with some vegetables and stock bones..." "Wait why are we starting with vegetables, why dont you start with the water and the salt?" SILENCE

[@zachary7032]

Is this supposed to be a lecture on science or on religion???

[@kevind.shabahang]

the students need to stop turning this into a philosophy discussion..you're not deep

[@TheBattistaGiovanni]

If the room is full of bananas not air then how one will evacuate or fill these bananas in half room? then how long we need to wait for the resting half room will be filled with bananas? chalkboard mathematics is not actual physics at all.

[@HariprashadRavikumar]

try to get educated

[@TheBattistaGiovanni]

So?this justification make all these invented lies true?

[@TheBattistaGiovanni]

Then you will be need to become a believer in"nothing"that produces everything. anyway good luck to be like him:-)

[@TheBattistaGiovanni]

Then prove them or accept them as grand lies.

[@TheBattistaGiovanni]

Huh? Your evidences are so strong you silenced me and you can hope i will convert to atheism.

[@j1o2n3a4s5k6]

iftikhar uddin bro you didnt really get the lecture did you ? He essentially made an Argument for a Creator...

[@TheBattistaGiovanni]

Ok, now provide evidence for one single subatomic particles on your choice.thank you

[@TheBattistaGiovanni]

Huh failed with Leonard Susskind imaginary PHYSICS?:-) ask him about black holes and dark matter too when he discovered/dreamed it/hem up?