149 karma · joined February 4, 2015
[1] https://www.democracynow.org/2017/11/15/special_report_from_...
The above may only be an issue of BigFloat, to be fair, since Float64 compiled in an instant (never measured, and the time never bothered me).
So Julia has solved a lot of problems for me, and I see great potential for it in the future.
www.damtp.cam.ac.uk/user/tong/talks/talk.pdf
The number that is quoted in some textbooks on String theory (but I do not have the refs.) is that gravity is 1/r^2 down to sizes of ~1 cm for extra dimensions.
The problem I had was that latex was turned into images, but changing the font-size of the reader did not change the size of the images, making the text readable, but the maths barely readable.
This is something I would love to see happen though.
https://www.reddit.com/r/academia/comments/8w98c8/shameless_...
I tried it this morning (lineageOS). Got the arm binary from github, `chmod +x`-ed it on my computer and scp:ed it over to my phone. Ran the binary and got a quick flash of the screen and a `exit status 1` [in termux].
Have not looked into it more than that. Since `browsh` depends on headless firefox, which is not in the termux default repository (it seems), I guess it won't work because termux does not have access to the firefox system app, if that even shits with the headless-functionality. (but here I'm just guessing, a work around may be available)
Would be cool to see working though.
Have not looked into it more than that. Since `browsh` depends on headless firefox, which is not in the termux default repository (it seems), I guess it won't work because termux does not have access to the firefox system app, if that even shits with the headless-functionality. (but here I'm just guessing, a work around may be available)
Would be cool to see working though.
It is unfortunate that they refer to the 26 dimensions...
> [...] particles as tiny vibrating loops of string that exist in somewhere between 10 and 26 dimensions.
... of what is known as "Bosonic string theory". It is called bosonic because it only has bosons (e.g. photons) and no fermions (e.g. electrons). This is obviously not a realistic theory because of that reason, and it also suffers other serious problems. But, this was the first formulation of string theory, not meant as a fundamental theory of gravity even, and if you do open some of the famous text books in string theory, you do find that it starts with the bosonic string theory. This is because it is a more gentle introduction.
The "between 10 and 26" comment is also a bit unfortunate. String theory is ten dimensional (space-time, meaning I include time in there). A lot of physics is formulated in terms of perturbation theory, meaning you have that the full result is expressed as an infinite sum of smaller and smaller terms, and you can truncated this infinite series and get a approximate result. This holds if the parameter you are expanding indeed is ever-smaller, which it isn't necessarily. One of those parameters (string theory has two of them built in) is the string coupling "g_s". If you start taking this parameter large than one, so the perturbation breaks down, string theory (type IIA in particular) grows an extra dimension into a theory known as M-theory. Note that this theory has no strings, it only has other fundamental objects. Similarly, there is an F-theory that is in some sense 12D, which also describes non-perturbative physics.
So, if physics in our universe is described by this non-perturbative physics, then sure, it's 11D or so, but we do not know which parameter regime of string theory our universe is in ( yet ;) ). But it is not a choice willy-nilly.
Then regarding effective theories against fundamental ones. Effective theories, or models rather, are things like: the inflationary model, cosmological constant to explain dark energy, standard model, minimally-supersymmetric standard model, F(R) gravity, DBI gravity, and so on. The problem is that there are too many of them. Claudia de Rham had a talk a month or so back in which she said something along the lines of (this is how I remember it) "We are quite good at excluding effective gravitational models, but we are however better at constructing new ones.". We need some deeper understanding of what is allowed when it comes to model building, and even theory building. But the point is, for gravity for example, that there are several models out there that are consistent with observations, but we do not know which ones can be consistently included in a fundamental theory.
And theory gives us ideas of what to look for. In this thread "seeing extra dimensions" are discussed, but it is misrepresented a bit. There are potentially several ways that we could start seeing evidence for extra dimensions, at least in principle. For example, "compactification" which means that we make the extra dimensions small, hidden for us, comes with the so-called "Kaluza-Klein tower" of particles, in which particles are essentially separated in mass inversely to the size of the size of the extra dimensions (small extra dimensions -> high mass). So this is one indirect way of how one could in principle see them (then they may be very massive, and virtually undiscoverable, but space-time warping brings down these masses... so we don't know).
Some of the particle physics experiments are looking for, in a sense, "anything that deviates" from the standard model. Note that for such experiments, any fundamental theory would have the same "problem" as string theory: it must show new physics at higher energies than already explored. LHC results are often seen as a "string theory is wrong"-result, which is not true, but what it rather shows is how boring the universe is at those energies, independently of the theory. Hopefully theory can give predictions in other places as well (in addition to the predictions of susy, extra dimensions, etc), like of what gravitational waves can say something fundamental about black holes.
> Sin[θ] //TraditionalForm //TeXForm
Did not know of this. Thanks!
> The tie-breaker is financial. Jupyter is winning because it's free [...]
It is a bit more nuanced than that. Personally I do not pay from Mathematica usage, so why do I like Jupyter more?
The Mathematica notebook interface is horrible. You may go "oh, neat" the first few times you try it then, at least I, get more and more frustrated on all the idiotic issues
* Indentation/text-wrapping. Write a long line that starts wrapping, it gives it a little indentation to signify this, an your next line that you have indented is slightly more indented, but it is really hard to see, so you have no idea of where your line-breaks are.
* Brackets. "[" are used for function calls and for part-specification. The number of square brackets in your expression makes it necessary hard to read when it is big enough.
* Jumping text. The notebook interface does not have the "auto-complete brackets" (maybe v11 does), so you add your first, all the text in the Cell gets reformatted and you have to find the fucking place you wanted end the bracket. This is akin to working with images in MS Word.
* Exporting. The notation is just ugly, fine, that is personal, but "Sin[]" as "sin()"... ok. Ah, good, it has a "Copy as Latex", nice... "Sin[]" -> "\text{Sin}[]". Really? Who in the world uses "\text{Sin}" for the sine-function and square brackets for function-calls when typesetting maths in Latex?
It is just a complete nightmare to try and incorporate these things into your workflow, at least for me.
Jupyter just behaves as you'd expect. Just that it is so much smoother to work with wins. For me, I do symbolic calculations, SymPy can do some things much easier than Mathematica, but a lot of things it can't or you have to work some more to get going. That Jupyter allows you not to have an aneurysm every day at work, which makes you actually wanna spend the extra time working it out.
[1] https://github.com/m-khvoinitsky/dark-background-light-text-...
https://hbowatch.com/hbo-acquires-asimovs-foundation-series-...
"[...] the electromagnetic repulsion or attraction between two charges—can be thought of as due to the exchange of many virtual photons between the charges."
so when the electromagnetic force mediation takes place, it exchanges virtual photons, and this is different from an object exchanging physical photons with another (which we would more think of as one object shining (if the photon is in the visible spectrum) on another).
How a virtual graviton would interact between BHs and other particles are up to any suggested theory for quantum gravity to explain.
The Higgs does not play that kind of role. It is a common misconception, since Higgs it often referred to as "giving mass to the other particles", which is true, and called the Higgs-mechanism, it does not influence the curvature of space-time that way. That is all due to the graviton (assuming, which it is also commonly believed, that gravity is quantised).
Mass is one thing, interactions between masses another.
(I don't know, I just have some vague memory of some Tomtom/Microsoft conflict due to FAT)
edit: user 'xxs' managed to type up the same issue before me (while I was typing mine).
1. The judge in the pirate bay case was a member of an organisation "Svenska föreningen för upphovsrätt"/"The Swedish Organisation for Copyright" (my own translation), and it was decided not to be partial to the pirate bay case. See for example [0].
2. Even if there were diplomatic pressures on Sweden from the US (which there were [1], their actual impact is what is in question), it should be impossible for a minister to influence the police directly [2]. Which makes for the pirate bay take down to be a ridiculous coincidence.
3. Sweden allows lawyers with their own, so called, "intellectual property" interests to defend suspects of file-sharing. See for example [3] which do give credit for this lawyer doing a good job, but just in principle this seems absurd (imo). I hope he is not allowed to be the defence lawyer if it is his own material at least.
[0] (Swedish, summary in English) https://lup.lub.lu.se/student-papers/search/publication/3800...
[1] https://torrentfreak.com/how-the-us-pushed-sweden-to-take-do...
[2] https://en.wikipedia.org/wiki/Ministerstyre
[3] (Swedish) https://overklass.wordpress.com/tag/fildelning/
Well... I'm not sure that's how you should see it. For example, skimming the document I mentioned, they have a section "Konsekvensanalys"/Analysis of consequences. There they address for example socio-economic impact, but not "popular opinion on the matter", or similar.
I think it would be more appropriate to see the investigation as objective (to some degree), and the final voting by the parties (on a potential future bill) as their considerations how this would impact their popularity. If the objective conclusion is that X should be done, a party may still not vote to implement X because of peoples opinion on the matter.
Yeah, was not sure how to explain the distinction, hence my quotation marks. Sorry for being vague.
So this "bill" is the result of an investigation started by the government. The investigation concludes (document posted by me elsewhere in this thread (in Swedish)) that it would be appropriate to change the law, and what the "bill" should look like.
Have not found the stage of the bill yet, the suggestion for a bill in the final document of the investigation is what I found so far.
The investigation appears to have been performed by people from various instances; governmental, academic, and industry. Only one person from industry; "Film och TV-branschens Samarbetskommitté", whose role was "sakkunnig"/subject expert.
They did not perform very well in the Swedish elections (less than 1%, 4% is limit to get seats), and after their initial push their momentum seemed to die off.
According to my personal view, a large part why the Pirate Party would not succeed in Sweden was that the party members (not the 'sign up for free on a webpage'-members, but party leaders) and their activists were very different in ideology. Party members were strongly libertarian while activists were more on the left.
[0] (Swedish) http://www.sou.gov.se/wp-content/uploads/2017/01/SOU-2018_6_...
Just as a side-note: When I started my Ph.D. studies we had an "introduction course", going through requirements for graduating, seminars by more experienced scientists, what to expect and so on. In that course I encountered the absolute worst seminar speaker when it comes to the subject of motivation. The seminar speaker said that "If your research does not have a potential to receive a Nobel prize, stop doing it.". The speaker was at the time in industry because achieving wealth was a similarly admirable goal. It was extremely discouraging.
So, not typical (I hope), but some argues that fame and wealth are the only reasons to do science.
The why is quite obvious, instead of upping the price on the per-minute/-sms charges on prepaid, they disabled it to force you to buy a monthly subscription instead. For me, this means that my phone does not work anywhere in EU anymore except Sweden and France (and I have two SIMs) unless I increase my phone spending with about 2000% (yes, I do not use my phone much), I cannot change the contracts because I cannot live in two countries at once [#], and will most likely lose the number I have had for over 20 years.
Even so, if I change to a monthly subscription they are allowed to cancel my contract if I "misuse" the new roaming rules, which I will because I want to keep my Swedish number but I will not live there for several more years (at least).
The new roaming rules only helps tourists (although I believe that the monthly fees have gone up all over EU since the transition to "roaming free" rules, so only the service providers are gaining anything on the transition). For people who have to be mobile across the EU it is a total nightmare. This has made me very angry (perhaps unproportionately so), and it is my opinion that the EU MPs that put forth this law should be ashamed and this is a complete failure.
[#] I can change it in France, since I live here, but I'm moving away from here soon, so why bother, but not to Sweden. So I have to break some country's law by saying I move back to Sweden when I don't, change my contract, move to where I actually am, and then lose my number anyway at 1000% the cost of my old card. And when I move, since this is not to France nor Sweden, but still in the EU, my phone will not work at all moving there! All things you have to do when moving to a new country I have to manage without a phone now.