nyssos

14 ms·

151.
by nyssos 3y ago
It's not an average. The limit is σ_x * σ_p >= hbar/2, where x and p are any two conjugate variables.
152.
by nyssos 3y ago
> This question is important enough that there have been papers written on it. I suggest you read https://pubs.aip.org/aapt/ajp/article-abstract/65/6/501/5300 ... This is a physics education
153.
by nyssos 3y ago
The "ruler" you're using is the other arm, which doesn't change in the same way: one axis stretches while the other compresses.
154.
by nyssos 3y ago
It has two arms at right angles to each other, and measures the difference between the two length changes via laser interferometry. This gets you the component of the wave polarized along the corresponding axes. No clue why GP thinks it &qu
155.
by nyssos 3y ago
D-separation still works for cyclic graphs, it just can't rule out causal relationships between variables that lie on the same cycle. And neither can any other functional-form-agnostic method, because in general feedback loops really d
156.
by nyssos 3y ago
> I doubt any mathematician ever learned their subject by mainly reading proofs. And I say that as someone who secretly enjoys reading and working through proofs of theorems. Understanding mathematics demands developing strong intuition
157.
by nyssos 3y ago
This isn't a quality of fit issue (and even if it were, linear models are not always sufficient). The problem is that different causal structures can entail the same set of correlations, which makes them impossible to distinguish throu
158.
by nyssos 3y ago
> It's not that hard. if the causality cannot make sense logically or plausibly, then you can reasonably reject it . no reasonable person would ever get the umbrella puddles thing confused. It's an illustrative example, taking
159.
by nyssos 3y ago
> How to know if model 1 or model 2 is more "real" or, for lack of a better term, more useful and reflective of reality? You don't. Given observational data alone, it's typically only possible to determine which d-sep
160.
by nyssos 3y ago
> As far as I know [Mormons] don't make this type of claim to be historically validated by peak reason. Mormons absolutely believe that their religion is backed up by history: the book of Mormon is about and ostensibly by various de
161.
by nyssos 3y ago
> It is an assumption Then don't say "certainly"
162.
by nyssos 3y ago
Then they would be replaced, because Average Redditors have very little power when it comes down to it. The real problem with bad but popular tech stacks is that they do exist to solve problems - just not ours. I want everything to be compa
163.
by nyssos 3y ago
Their point is that standard YAML is a poor fit for dependency config files.
164.
by nyssos 3y ago
You don't generally talk about "scattering" off a field, but photons and gravitons can scatter off each other, sure.
165.
by nyssos 3y ago
> In other languages at that time the for loop was written in terms of a range, but without a strong range abstraction such loop is really primitive and limited in applicability. That's a good thing: it gives you a clear syntactic m
166.
by nyssos 3y ago
No, the gravitational analogue of voltage is the gravitational potential energy. We can freely shift them by constants because absolute potentials are unobservable: only potential differences have physical consequences. Mass, like charge,
167.
by nyssos 3y ago
Photons do interact with each other gravitationally. It's not as simple as just attracting each other - the Newtonian limit doesn't work here - but parallel photon beams going in opposite directions, for instance, will be deflec
168.
by nyssos 3y ago
> However, whether that translates to a loss in momentum is a bit more fuzzy and I really can't tell whether it does or doesn't. Yes, redshifted photons lose momentum. Momentum (really the stress-energy tensor) is conserved loc
169.
by nyssos 3y ago
> in order for any kind of interaction you need to lose some energy This is not true, elastic scattering is very common.
170.
by nyssos 3y ago
The no-hair theorem very likely goes through semiclassically as well, at least where global symmetries like baryon number are concerned, but yes, ultimately no one knows for sure what the story is for the undiscovered true theory of quantum
171.
by nyssos 3y ago
It does not. Time-reversal is antiunitary, so you when you apply it to p_0 = i d/dt, you pick up one -1 from i and another from d/dt, and they cancel out.
172.
by nyssos 3y ago
No, an antimatter black hole is literally just a black hole. They're the same thing. > Does the total mass convert to energy? If so what happens to the gravitational effects? Energy density and mass density are the same thing too.
173.
by nyssos 3y ago
The quantity coupled to the curvature is the stress-energy tensor. In local coordinates, this can be represented as a (1+n)x(1+n) matrix where n is the number of spatial dimensions, with components given by [mass density, mass flux =
174.
by nyssos 3y ago
> The controversial scientist Bob Lazar Lazar was briefly a subcontracted technician at Los Alamos: not a scientist, controversial or otherwise.
175.
by nyssos 3y ago
> But also gravity doesn't have "charge". If you treat GR as a gauge theory, and plug local Poincare symmetry into Noether's theorem, the corresponding conserved current and charge you get out are the stress-energy te
176.
by nyssos 3y ago
> Why did they think it would have negative gravitational attraction? They didn't. There are very strong theoretical reasons (among them, CPT symmetry) to expect antimatter to gravitate normally. But it's still good to actually
177.
by nyssos 3y ago
An "antimatter black hole" is just a black hole. There might still be something behind the event horizon to annihilate with, there might not, the question might be meaningless, but in any case you're not getting anything back
178.
by nyssos 3y ago
> Very few jobs in industry need a PhD. Most are ok with a masters. This varies dramatically by field.
179.
by nyssos 3y ago
They're talking about idempotence of `merge(a, _ )` (under function composition), whereas you're talking about idempotence of `a` (with composition given by `merge`). Same property, different object.
180.
by nyssos 3y ago
Those things don't constitute a capital strike. Businesses don't suppress wages to strongarm the government, they suppress wages because they want higher profits. Likewise with prices. Return to office might be more organizational

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