rotorblade

9 ms·

31.
by rotorblade 10y ago
For academic seminars, I have started to always go through David Tong's ``How to Make Sure Your Talk Doesn’t Suck'' [0], before and after writing the presentation. I believe that it has at least helped me improve and feel mor
32.
by rotorblade 11y ago
All _fundamental_ particles gets their mass from the Higgs (up to some issues with the neutrinos). Composite particles, say the Proton, is a strongly coupled system (that is, can not be described by perturbation theory) and it does not have
33.
by rotorblade 11y ago
Contrary to _dilerium's answer, I think this, in at least Sweden, was a quite significant factor. But that must(?) have changed now. During the last wave of immigrants coming to Sweden, the whole range of parties, except for the Left P
34.
by rotorblade 11y ago
Not sure how it works in Denmark, but in Sweden the life sentence is also usually refereed to as being "max 16 years", or some similar number between 10-16 years. However that is not quite the whole story. In Sweden, a life senten
35.
by rotorblade 11y ago
I'm in string theory as well, most of my knowledge about LQG is mostly from other string theorists. From my experience, string theorists can be extremely hostile towards the ideas in LQG and the people involved in it. So I would not qu
36.
by rotorblade 11y ago
In the way string theory does it -- unify SM (or generic QFTs) and GR, that is -- there emerges several new things that could give answers to dark matter (for example weakly interacting SUSY particles) and dark energy/cosmological cons
37.
by rotorblade 11y ago
> photons are gauge bosons and thus are automatically their own antiparticle So is W^+, but it is charged, hence not its own antiparticle. W^- should in this case be considered the antiparticle.
38.
by rotorblade 11y ago
Well, it is a good feature of a theory. Imagine that you would have two competing theories but they give different predictions, then a measurement on those predictions would determine which is which. (If they give the same predictions, an i
39.
by rotorblade 11y ago
I'm not sure how to explain it in non-technical terms, but the problems of neutrinos and their mass is basically: One is not allowed to add mass-terms to the Standard model (that is a term in the expression that explains the particle p
40.
by rotorblade 11y ago
I have only used some of the modules that are available for SymPy. Most of them are not complete enough to use professionally, but I try to spend some time to learn them since I would prefer to use them when they get more complete -- but th
41.
by rotorblade 11y ago
Fair enough. Perhaps my issue more correctly lies in the close-to absolute trust some of my colleagues have for mathematica. Since mathematica is so much faster and feature rich people use it and only very occasionally is it verified by som
42.
by rotorblade 11y ago
> People who like open source will never use anything else [...] I like open source, but I _have_ to use mathematica to be as productive as my peers in my field. The open source tools that exist are indeed inferior and that's why I
43.
by rotorblade 11y ago
I find this approach quite interesting, I'm not depressed myself (I have not been diagnosed with clinical depression, at least) but I am diagnosed with an anxiety disorder. At first glance this sort of approach seems also to be applica
44.
by rotorblade 11y ago
Yes, good point. I was actually thinking about special functions and that they are usually defined through differential equations (so, yeah, I more or less stole the idea from there and did not cite it properly :-/ but I did not want t
45.
by rotorblade 11y ago
>> Some of them don't even really have solutions (non-linear differential equations). > There certainly are differential equations without solutions [---] These statements are confusing, I think. Some DE:s might not have analy
46.
by rotorblade 11y ago
> Whose going to charge the US with a war crime? No one. Nicaragua did: https://en.wikipedia.org/wiki/Nicaragua_v._United_States
47.
by rotorblade 11y ago
Very fair point, its intended use was indeed not as a chemical weapon. It would however seem reasonable that, even if not expected at the time, people in charge could be held accountable after the fact as well. However this is perhaps way b
48.
by rotorblade 11y ago
Does any one know... Was this considered 'war crime', or was it a too modern way of conducting war so that it was not covered by the international laws at the time? If against international law or not, has it ever been a case in a
49.
by rotorblade 11y ago
> Because there is no reason to expect stars going around a galaxy to follow keplers laws for two body systems. The 'Kepler' law for galaxies are modified to accommodate for a mass distribution. See e.g.: https://en.
50.
by rotorblade 11y ago
The main subject for such an approach is 'Modified Gravity', where one in different ways would modify gravity to reproduce 'dark-matter' effects and still reproduce the same results as GR has.
51.
by rotorblade 12y ago
> doesn't provide any extra prediction But it does. It predicts extra dimensions and it predicts supersymmetry. However it might be that these are only visible beyond our achievable energy levels such that we cannot verify them. The
52.
by rotorblade 12y ago
Oh, I do simplify a lot and hide myself under "Fundamental physics". You are absolutely right to call me out on that. :-) But lets think about one of the examples that you brought up: > - Black hole information paradox This is
53.
by rotorblade 12y ago
Not completely sure of what you are saying, but I will try and answer some points. > Well - relatively does. QFT is weirder. Part of it reduces to plain vanilla Maxwell, but it also includes forces [...] Indeed. QFT is usually referred t
54.
by rotorblade 12y ago
In a sense you are both right, and in relation to what I wrote, it is hidden in my sentence: "There are some exceptions to these, but I will exclude these for now, since they are a bit technical." Take for example the Anomalous ma
55.
by rotorblade 12y ago
> The thing I find unsatisfying is... I suppose my use of the word "regime" is unconventional. What I mean is a "parameter regime", or "for a certain range of a parameter". For example, for the range in whic
56.
by rotorblade 12y ago
> In yet simpler terms: Newtonian mechanics is Quantum mechanics (except that it is always off by a miniscule, totally ignorable, amount. Except in extreme circumstances) I believe we are saying the same thing. Your "as Planck'
57.
by rotorblade 12y ago
> we can't measure what we don't know. This is interestingly put, and I would not completely agree with it. Let med give two examples: 1. Before Quantum mechanics we could measure the Photoelectric effect (that is, light that i
58.
by rotorblade 12y ago
Indeed. I commented on this earlier: https://news.ycombinator.com/item?id=8996190
59.
by rotorblade 12y ago
It has the unit-dimension the same of acceleration (that is [Length]/[Time]^2), so it should be read as: 'Every year, the velocity of the distant quasars (going away relative us) is increased by 1 cm/s.'
60.
by rotorblade 12y ago
It does actually. The statement: "What’s more, there is an energy associated with any given volume of the universe. If that volume increases, the inescapable conclusion is that this energy must increase as well. And yet physicists gen

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