I was reading 2-year old meta post here, and it seems most of the answers saying that it should be on-topic (as theoretical physics) as science should answer non-mainstream questions to avoid censorship.
However it's still not clear for me and I know that there was some long debate on this and m...
Oh by "working" I mean taking notes and assembling a list of questions so that if I had a test on the material I could re-study it more quickly. + some notes and projects. I'm almost done with 1-50 but I did skip the small nonlinear oscillations sections.
And my pace has been scattered since I started the quarter
@NeuroFuzzy: So as I said, I'm reading though it (starting this weekend, at some pace I've not settled yet), gonna put stuff systematic on my notebook (axiomsofchoice.org) and (if people tune in) post some elaborative stuff for discussion on a place like /sci/
@MarkMitchison how to solve $\delta \rho / \delta t = -i[\rho,H] + L_(deph)(\rho) + L_dissipation(\rho)$ where the deph and dissipation from plenio and huelga?
@NeuroFuzzy: Not really, in the sense that the traffic is low and the people are young. But the traffic is higher than here, and the poeple are funny.
but you can have some interesting discussions. E.g. here I answer some math student what I know about categorical logic: archive.moe/sci/thread/7140705
@ACuriousMind Let $G/H$ be a coset space. I want to show that multiplication of equivalence classes is well-defined, i.e. that the product of equivalence classes is itself an equivalence class. So let $[g],[g']\in G/H$ be equivalence classes. Let $gh$ and $g'h'$ be representatives. Then I should be able to put $ghg'h'$ in the form $gg'h''$, so that it defines an equivalence class.
I don't have all definitions in my head, but G/H is a set, a priori, and you wont always be able to induce a group structure (coming down from G) on it
>..On the other hand, the subgroup N is normal if and only if gN = Ng for all g in G. In this case, the set of all cosets form a group called the quotient group G / N with the operation ∗ defined by (aN ) ∗ (bN ) = abN. Since every right coset is a left coset, there is no need to distinguish "left cosets" from "right cosets".
now this says normal=> group structre
not sure to what extent it fails to capture when exactly a group structre comes down
(the induced one, obviouly the trivial group structure always exists)
and /sci/ is "a shithole", in the sense that the niveau is low because there are a lot of kids. The people are okay and the content can be funny (if you're not trolled easily). Let's say its more worthwhile than reddit, imho.
@TAbraham A link would be helpful, because all the rooms I see other than this one and the Physics moderators chat room are titles "Discussion between ..."
“A person is not to be blamed for his nature. Rather, he is to be blamed if he acts according to his nature.”
-Al-Junayd in ‘Hilyat al-Awliya”
Our community needs to understand that NO ONE is condemned to Hell simply because they have a desire that is not permissible to engage in.
Men ...
@0celo7 you know how once you integrate something, you end up with $F(b)-F(a)$, how do you write the vertical line in LaTeX with the stuff you're supposed to plug in?
Guys, I'm inclined to write a long self-answered post about the Caldiera-Leggett model and how to understand dissipation in energy conserving theories.
Is there a preferred format for this? Is a simple self-answered question the right way to go?
@MarkMitchison how to solve $\delta \rho / \delta t = -i[\rho,H] + L_{deph}(\rho) + L_{dissipation}(\rho)$ where the deph and dissipation from plenio and huelga?
I answered the questions. The inflation issue came up because Steinhardt featured on Horizon program and the BICEP2 team hyped their paper with a video of Linde packing his bags for Stockholm. As for objective answers, there is no evidence for string theory, and you might like to ask Liam McAllister how gravitational waves from the instant of creation can be detected in CMB photons emitted 300,000 years later. To be blunt: it's like tapping a jelly with a spoon, then throwing it in a blender for a quarter of a million years, then claiming you can still detect the ripples. — John Duffield2 hours ago
Am I the only one who's getting the vibe he's just seen some pop-sci stuff? Not to be rude or anything, but it seems he's reluctant to bring any real arguments to the table.
@Danu Yep, just downvoted that answer for not giving a single physical argument in trying the answer the question, but only referring to pop-sci articles.
@infinitesimalsimplicio Nope. Strangely, I have heard some people recommend it, although I was convinced Penrose has become a crackpot. Maybe only after he wrote the book...
On the other hand, having "strange" stances on some research issues must not necessarily impede one's clear vision on the more basic (at least in your view) issues.
E.g. 't Hooft, who is still a (good, I think) professor at Utrecht teaching "normal QM" and stuff even though he's working on wacky cellular automata and stuff
@ACuriousMind I'm tempted to respond with this: "I was just pointing out that you did nothing to substantiate your answer. String theory has nothing to do with this, nor do your handwavey (at best) objections based on bad analogies which I doubt you can make into precise arguments"
They were more about ontology than neuroscience and really didn't show any effort to study actual neuroscience. He seemed to just want to try to make weird mathy claims about how reality is perceived.
@Danu lolol that certainly was my impression reading Penrose. And his partner in crime Stuart Hameroff seemed to be piggybacking off of Penrose's fame.
Cool. I'll check it out. I think I saw a video with that dude in it.
@alarge I'm very excited. I'm taking my first neuro class Monday. It will be an introduction to signaling and modeling. We'll use MATLAB and stuff. It should be awesome
@alarge I'm not sure tbh. The guy teaching it wrote the textbook [linked below] I have no idea if he's a good teacher, but I think the book is nice. We are also using the companion book.
Ah, so it's more of a signal processing 101 type of course (with applications from neural stuff, rather than MP3, JPEG, say, which are often used in similar courses for EE/computer scientists).
When philosophy is guided by mathematics, we get a pedagogically useful oversimplification of mathematics. When mathematics is guided by philosophy, we just get a stifled, bastardized version of mathematics. Let mathematicians lead the way, and philosophers follow after.
@ACuriousMind I'm having trouble working out the left invariant vector field of $\mathrm{GL}(n,\mathbb{R})$. So I have the vector $V=V^{ij}\partial/\partial x^{ij}|_e$ at the unit element. Then the left invariant vector at some $g$ is $X_V|_g=L_{g*}V$. I'm not sure how to do that pushforward. I know the rule for "regular manifolds" and "regular vectors" obviously. I just don't see how to apply it here.
anyone know if it's possible to nondimensionalize a difference equation? I don't think it is.. we can nondimensionalize a differential equation though.
in particular, math doesn't even really know dimensions (mathematicans have a hard time with the general concept even), and so I doubt there's something inherently dimensionful to any difference equation
anyone want to take a look at the problem anyway and figure out what it's asking? I can do the last two questions, but they are connected to that problem child question I have to do first
@0celo7 Since your pushforward is in index notation, it's the index that tells you whether it is right or left action, not the action position in the formula
@NikolajK on 2c it says to rewrite the model and rescale it. So does it mean that I have to use subsitution and put those given values into the difference equations so I end up having $Y_{t+1} =$ and $X_{t+1}=$ ?
ok... so let's see let's have $Y_t=\frac{E_t}{ka}$ so do I have to rearrange this to have $Y_t(ka)=E_t$ and subsitute it into B_{t+1}=ke^{-c\frac{E_t}{B_t}}$ @NikolajK
The Physiccs work in this field is rigorous enough. Hawking and Ellis is a standard reference, and it is perfectly fine in terms of rigor.
Digression on notation
If you have a tensor contraction of some sort of moderate complexity, for example:
$$ K_{rq} = F_{ij}^{kj} G_{prs}^i H^{sp}_{kq}$$
...
@0celo7 He's got a point about "exponential growth" and "diagrammatic notation" there when it comes to efficient notation, but I firmly believe conceptual clarity is worth a few more key- and penstrokes.
"We give an example of a formula involving the sinc function that holds for every N = 0, 1, 2, ..., up to about 10^102832732165, then fails for all larger N. We give another example that begins to fail after about N ~ exp(exp(exp(exp(exp(exp(e)))))). This number is larger than the Skewes numbers."
“A person is not to be blamed for his nature. Rather, he is to be blamed if he acts according to his nature.”
-Al-Junayd in ‘Hilyat al-Awliya”
Our community needs to understand that NO ONE is condemned to Hell simply because they have a desire that is not permissible to engage in.
Men ...
The Physiccs work in this field is rigorous enough. Hawking and Ellis is a standard reference, and it is perfectly fine in terms of rigor.
Digression on notation
If you have a tensor contraction of some sort of moderate complexity, for example:
$$ K_{rq} = F_{ij}^{kj} G_{prs}^i H^{sp}_{kq}$$
...
