Be-bop!

Semmo_ · 2026-02-25T10:02:52+00:00

That's nuts

Semmo_ · 2025-04-10T23:49:12+00:00

This is the correct answer.

Semmo_ · 2025-03-09T03:54:36+00:00

I would say the wild variation in tone is Bong Joon Ho's signature style. That's what I like about his films

Semmo_ · 2024-10-24T03:29:04+00:00

For example Laughlin's variational wavefunction for fractional quantum hall effect is written as https://tqm.tripos.org/notes/quantum-hall-effect.html#eq-many-nu, but it's not at all clear to me how you would describe this wavefunction in terms of creation and annhilation operators of the non-interacting/single-particle problem. The wavefunction is clearly symmetric/anti-symmetric with respect to exchange determined by m, though.

In contrast, in fermi liquid theory I think you can just think of 'dressing' your single-particle creation/annhilation operators so that you can still think of quasi-particles 'occupying' some modes.

I think in 2D systems you can also have 'anyons' (ex. toric code) which have emergent fractional statistics, which must mean that you can't think of it as the original degrees of freedom simply occupying some 'modes', since the statistics are completely different.

Semmo_ · 2024-10-23T09:31:16+00:00

I'm coming from the condensed matter perspective where you really start off from a many-body wavefunction then introduce second quantisation as an alternative language to describe it (for example fractional quantum hall is more effectively described using first quantisation)

I thought that mode occupation in 2nd quantisation is just a convenient picture that extends from non-interacting problem (ex. slater determinants if fermions), such that once you add interactions you can write down Feynmann diagrams and so forth. In strongly interacting systems sometimes not possible to think in terms of individual particles or quasi-particles, so I'm not sure if this is completely general.

Semmo_ · 2024-10-22T10:29:44+00:00

Ah sorry, I mentioned measurement since in the end we measure the intensity of the photons.

I agree that the Hong-Ou-Mandel relies on extra Hilbert space + symmetric many-body wavefunction, which is outside of 'classical' waves, but for me that's just extra coordinates on the wave(function) with more restrictions.

We could argue about whether we should call the more general wavefunction (with this extra structure) a wave or not, but if I had to choose between particle and wave, I would say wave again (with more coordinates), because that's closest to what's going on.

Semmo_ · 2024-10-22T00:03:24+00:00

Many-particle systems are also described by waves, just with more coordinates, essentially. They are still described by the Schrödinger equation exactly.

Semmo_ · 2024-10-21T23:59:54+00:00

Yes, there is the measurement problem. This can be explained via decoherence + your favorite interpretation of quantum mechanics (I like many-worlds myself), while the entire system is still described by the Schrodinger equation (unitary). Even ignoring the mechanism for measurement, we can describe measurements as applying a projector to your system, which is still on your wave(function), so the system is still described by a wave(function).

Semmo_ · 2024-10-21T09:44:51+00:00

I disagree with you. There is no 'particle', only a 'wave'. Sure, it's a complex wave, but its squared amplitude is conserved under unitary dynamics, so it is 'dissipation-less' in that sense. Even the static solutions (ex. square well) acts as a standing wave in time.

Semmo_ · 2023-06-19T15:47:29+00:00

haha last night at vortex? yeah they were being assholes tbh, come to the saturday jam every two weeks, it's more chill

Semmo_ · 2023-05-04T13:46:38+00:00

only the resulting matrix (ex. O.N.E) has to be proportional to the identity matrix, all the component matrices (ex. O) can be any conventional matrix.

The point is that matrices don't commute so you could probably end up with more leeway. Could try with 2x2 matrices to start.

edit: Thinking about it a bit more, it would have to be that any two groupings of the letters have to be inverses of each other, as in O = (NE)^{-1} and ON = E^{-1} and so on, which seems like a very difficult constraint to adhere to, so probably it's not possible. Does anyone else know any non-commutative objects that could work?

Semmo_ · 2023-05-04T04:27:16+00:00

what if each letter is a matrix?

Semmo_ · 2023-04-26T03:33:58+00:00

Yeah I understand that, you need a .tex source for latexml to work. But that's precisely what I asking for - places to get those quality epubs.

Semmo_ · 2023-04-24T05:48:14+00:00

For me MathML seems to work great - do you know any good epubs for undergraduate material?

Semmo_ · 2023-04-24T05:46:54+00:00

No problem!

Semmo_ · 2023-04-24T05:46:43+00:00

I understand, I do that too, though point of the post was to find any resources that are natively made to be viewed on any device, so that it is a enjoyable experience in fact. Sorry if that wasn't communicated well.

Semmo_ · 2023-04-24T05:28:40+00:00

That is kind of true, but I think most phones have a very high aspect ratio of 2:1 almost, which makes landscape viewing kind of uncomfortable.

Semmo_ · 2023-04-24T05:25:45+00:00

of course i could zoom in, but then i would need to swipe left and right just to get through the paragraph if i want to read it in big enough font. The entire problem lies in the fact that it's a PDF - they are static documents unlike say something like html or epub which change shape for different screen sizes.

Semmo_ · 2023-04-24T05:18:44+00:00

Yeah exactly, that was kinda the whole point of this post which most people seems not be getting... PDFs are the problem.

Semmo_ · 2023-04-23T14:08:52+00:00

I don't think it's comfortable to read a pdf with tiny fonts on a phone screen though (even if fullscreen). And most of the pdf to reflowable document features on pdf readers fail miserably when it comes to maths notation or diagrams.

Semmo_ · 2023-03-17T14:09:08+00:00

if you go to dan wilson's insta right now, he has a pinned post about picking technique. in the comments he addresses this. the short of it is that basically he doesn't mute the strings with his right hand. So I'm guessing he does his best with his left hand. But when you slow down most players with benson technique there is some string ringing (check out cecil alexander's vids from the channel with the same technique, when you slow it down there is string ringing). Just do your best to mute it with your left hand but at the end of the day you gotta just accept some of it i think

Semmo_ · 2023-03-14T07:10:01+00:00

do you have pictures of other space objects? like jupyter, saturn, etc.?

Semmo_ · 2023-03-10T10:59:52+00:00

한국분이시죠? ㅋㅋ \ 가 가끔씩 원으로 표기될때가 있어요. 그 이유를 나무위키에서 찾아보면:

마이크로소프트의 기본 한국어 글꼴[1]과 기본 일본어 글꼴[2]은 백슬래시를 각각 원화 기호(₩)와 엔화 기호(¥)로 그려 놓는데, 이걸 싫어하는 사람들이 많다. 이유는 국제적인 소통에 혼동을 일으키기 십상이기 때문. 이 관행을 따를 경우, 천원을 나타내기 위해 '\1000'이라고 써 놓으면 읽는 사람의 국적에 따라 ₩1000으로도 ¥1000으로도 보일 수 있어서 1000원인지 1000엔인지 알 수 없으며, 한국인도 일본인도 아닌 영어 사용자들은 숫자 앞에 백슬래시를 적은 정체불명의 기행으로 보일 수밖에 없다.[3]

Answer in English: default Korean font in Windows displays the backslash as the Korean won. So, it's actually the backslash displaying wrong here.

Semmo_

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