I miss the times... — NOS4A2

Back in those times, you were obsessing over Hunter Biden without any evidence of any conflict of interest in a Biden administration. Nowadays you're obsessing over Hunter Biden without any evidence of any conflict of interest in the Biden administration.

It doesn't seem like _that_ much has changed, apart from the fact that you managed to get rid of the big orange baby in the meantime.

By universal I was meaning ranges of values, not types of system. Your examples all suffer the same problem: for a given system, Hooke's law applies only for a (often very narrow) range of values, therefore isn't general, so has dubious claim to law. There's no problem with having a law that applies only to springs, if the law is general. The problem with Hooke's law is that it relies on something it cannot: the material properties of the system (which then change when you test Hooke's law beyond that narrow range of applicability).

The problem, it isn't about censorship, but more of self-censorship. Or even more basically the attitude that if you made the argument that this incident was actively perpetuated by Russia being a trope of the anti-immigration activists. — ssu

Indeed, hence my analogy with the self-imposed ignorance of the UK Conservative government. It's too difficult to handle the fallout of acknowledging it, so don't.

But this has nothing to do with the mode of discourse about immigration generally, or as you put it:

We face the danger where debate about various policies are taken over by the larger "culture war", dumbed down to simple rhetoric which doesn't put into context the actual issues at hand. Hence there isn't much actual debate of the real political issues, but a discourse separated to an ideological simplified realm. Debate about actual policies or international politics is done behind closed doors and not openly in the media. Who would say what actually is true, if you get a ton of hate mail and your career is threatened. — ssu

which is a clear reference to "You can't say anything any more" cancel culture culture (distinct from cancel culture), specifically around the topic of immigration. It's this typical conflation I was pointing out, because the reasons for Finnish authorities not talking about Russian migrants were incredibly specific (as you yourself have described them), not symptomatic of a broader problem in discussing immigration (same goes for the UK's wilful blindness on illegal alien numbers).

Maybe we are nuts. But I assume you never have heard about Finlandization. But the thing is that non-aligned countries like Sweden and Finland talk about Russia differently than NATO members like Estonia, Poland or Norway. — ssu

I'd say get thee into Nato but I'm not sure how much juice is in that tank. But still... would Crimea be in Russia if the Ukraine had done the obvious thing and acted on its intent to join? They hedged their bets for fear of bringing Nato to Russian borders and look what happened: territory annexed.

Being open right from the start is in my view the correct way to do things, because otherwise you will just give ammunition to anti-immigration populists who will concoct conspiracy theories around immigration policy and the role of the government. It's far more damning if the government withholds information or just looks as if it is withholding information of a "hot potato" issue. — ssu

I mostly agree, but as I said immigration is discussed openly, however the narrative is more or less owned by hate. Brexit was an immigration discussion. The remain side argued for pragmatism and humanitarianism. The leave side faked images of swarms of migrants queueing at our borders. It didn't matter that such propaganda was outed as such prior to the vote. Hate is blind but vigorous.

It is the _quality_, not the amount, of discussion that is the problem. In service of better, more open discourse, the onus is on all parties to be honest, thoughtful and self-representing. If Trump supporters for instance have a problem with being "censored", i.e. being called racists when they e.g. call Mexicans rapists, the onus is on them to up the quality of their discourse, not on others to self-censor accurate descriptions of their behaviour. Let someone be a xenophobe by all means, but if they have a problem with being named as one, they're not an honest, thoughtful, or self-representing xenophobe :D Of course, I doubt that's feasible.

BTW perturbative quantum field theory was recently put on pretty firm mathematical footing (see Perturbative Algebraic Quantum Field Theory by Kasia Rejzner). This uses Greens functions which are calculated recursively (i.e. G = f[G]).

Notice Kenosha, that the OP isn't at all about Mexico. — ssu

No, but a) it was about immigration in general, despite the specific example of Russia having nothing to do with any other immigration case, and b) you nonetheless found the connection to Mexico in later posts.

And people hearing dog whistles (or assumed dog whistles) if you start a thread about some politicized issue. — ssu

As I said in my first response, I see no barrier to discussing the Russia story at all, it's interesting. You started out in your OP claiming that this was somehow subject to censorship, a point I take issue with, but you seem to be sticking to that line. That's a very common claim these days from your side of the political divide. People can't shut up about not being able to speak.

Something the same happening in let's say the US-Canadian border, and I could evade the crap only with simply not following the media here, which does report even all the small things that happen in the US — ssu

Yeah I get that. But my point is that it doesn't follow that the world not talking about Russian cyclists has anything to do with immigration being taboo. The West discusses the US in far too much detail (I see far more US news than British news), but they don't particularly talk about Finland, or Norway, or Sweden, or Belgium, or Holland, or Austria, or... It's not evidence of a cover-up, just that foreign affairs are not egalitarian.

As for why Finland didn't talk much about it, sure, maybe you're all nuts (my Norwegian friends assure me of this), but here's another theory: it's not that immigration is a taboo subject, but rather that the failure to protect borders at the height of paranoia about Russia was politically awkward.

We have a comparable thing here. The foreign office has been trying to get a count of how many illegal aliens are in the UK for decades, but it's consistently blocked by No. 10 and the home office. Why? Because if you don't have the numbers, you don't know how "bad" it is and don't have to deal with grief about it from your anti-immigration backbenchers and constituents. You'd have to _deal_ with it (and them) then. So they just don't talk about it. Not because it's taboo, but because it's a topic poisoned by right-wing hate. Even right-wing leaders don't want to face that.

Sure, it's much more useful for more ideal mechanical oscillators like atoms. Not very universal for springs and stuff like Hooke had in mind.

1. Russian warfare via immigration against Finland is bad.
2. Therefore immigration is bad.
3. Therefore immigration of refugees is bad.
4. Therefore "silenced" (and yet ubiquitous) ab initio anti-immigration arguments are justified.
— Kenosha Kid
No,I'm not saying that. But seems you think that I am. — ssu

Let's check first how wide of the mark I am. Correct me where I deviate from what you say you meant.
1. Russia engaged in a bizarre demonstration of power by flooding neighbouring countries with immigrants.
2. People can't talk about [1] because immigration is taboo.
3. But we need to talk about immigration, viz [1].
4. This includes accepting the fact that, while people are people everywhere, subcultures differ, and some subcultures would, translated elsewhere, be intolerably criminal, e.g. Mexican subcultures in Finland.

If the above is correct, perhaps you can sketch the delta between that and my original summation of the implicit argument, since they look pretty darn adjacent to me. My point was that [4] has absolutely nothing to do with [1] and yet was presented as supported by it, via [2-3]. When the conclusion had nothing to do with the premise, something is amiss.

Well, Kenosha Kid, can we have a discussion without the poison of polarization? It's not about "winning" the argument, proving others wrong, but exchanging views and learning from others. — ssu

You miss my point. I was describing historical content of right-wing media (at least in English-speaking nations), not laying out a manifesto for future conduct here. The problem isn't that progressive people have made anything related to immigration taboo. The problem is that right-wingers don't seem to be able to talk about Russian invasion of Finland and Norway without bringing up Mexican immigrantion to the US, which makes the debate not only toxic but meaningless except to like-minded paranoiacs, who therefore dominate the discourse. And this holds pretty much across the spectrum of politics.

For my part, I don't care that much. I believe, as you seem to, that we should take in refugees of war, famine, societal collapse, and soon climate change. Beyond that, have an immigration policy and manage it. It doesn't matter that much to me what the policy is.

Ok, do you have any idea how remote the Norwegian-Russian border is? — ssu

I've crossed the Finnish-Russian border, so an idea, yes, but not been there.

I assume that if I start a thread with "Discourse and Reality" and have pictures that remind you of Nigel Farage, do you assume I'm in his camp — ssu

No, what I said was that these photos aren't as ghastly to everyone. I presume you posted it to have an impact and as evidence, right? But they're not very impactful images, or compelling evidence, unless you're predisposed to be alarmed and swayed by them. You're obviously very concerned about immigration (you started a thread on it). As per two paragraphs up, it's not something that bothers me much. I guess my immediate response is, 'They look cold, poor things.' Not, 'Oh my god, we need to start talking about something right-wing media never shuts up about.' But like I said, most people would probably be apathetic anyway. Could you imagine a redneck giving a crap about Russian cyclists in Norway? :rofl:

Hey, Einstein field equations are basically a glorified Hooke's law — SophistiCat

I don't see how. The field equations are general (hence "general relativity") which seems a good condition for a 'law'. Hooke's works as long as you don't compress or stretch _too_ much, where "too much" could mean "almost anything" :rofl:

Yes, it is possible for all the air in your room to spontaneously bunch up in one corner, but you should not take that possibility seriously, on account of its vanishingly low probability. — SophistiCat

Which tbf is now, post quantum theory, true of anything. Individual particles are statistical quantities.

Yet another thing to read (Vacuum energy and cosmological evolution). — jorndoe

Dat's da same paper!

You could work your entire life only to make a scratch on the edifice, but you’ll surely be forgotten afterwards. — Nicholas Mihaila

Ego seems to be root of the problem. You want a legacy but are guaranteed none. The best I can think of is: you're more likely to be remembered if you strive for it. But it's a crappy raison d'etre in the first place imo. The universe is an interesting place. Since we each exist in it only briefly, makes sense to know a thing or two about it before we die.

And this brings me to the real issue here: We face the danger where debate about various policies are taken over by the larger "culture war", dumbed down to simple rhetoric which doesn't put into context the actual issues at hand. — ssu

As far as I can tell, this is the explicit part one of your thesis: that you're being constrained against discussing a particular and interesting event (a mode of warfare) because it falls under the banner of a tabboo subject (immigration). For all I know, that is the case where you are, but that isn't a global "We". Britain apparently has no problem faking mass immigration stories and both British and American leaders have enjoyed great success describing immigrants generally as dirty criminals, so I don't think anyone there would bat an eyelid at bemoaning Russian immigration into Finland as warfare. If they're not, there's three more viable reasons:
1) it didn't really happen;
2) it happened, but we didn't know;
3) we know, but we really don't care (very likely)

From where I am, far from the right-wing paranoid fantasy that you can't speak the truth about immigration without being cancelled, the right-wing press actually devotes a lot of its energy to anti-immigration propaganda in a manner that betrays the fact that, far from being a considered opinion based on evidence a la Russia, it is against immigration _even in principle_ along lines adjacent to racial purity arguments (e.g. they speak the wrong language ["I don't recognise this country any more!"], have the wrong religion ["They're trying to cancel Christmas!"] or otherwise the wrong culture.)

If dialogue about immigration is difficult and heated, that's because it's been poisoned by racist, nationalistic, traditionalistic i.e. conservative sentiment. You prove the point yourself by making the instantaneous leap from Russia's typical wrongdoing (a non-controversial topic except to the Putinbots) to Mexicans-have-the-wrong-culture arguments that have no analogy with Russian cold warfare.

Probably a better example (required since immigration-phobia in the right apparently blinds them from distinctions between immigration stories) is Syrian refugees in Germany and France. A large number of sexual assault allegations were made by women, the picture painted being that this mass influx of Syrian men brought a sexually misogynistic culture with it. I even know women personally who were so molested*. That said, we're also told this happens to all women every day anyway, and I'm not sure how strangers on a train are verifying each others' residential status*. Did the governments fail to respond to the danger they put women in because they were afraid to say anything negative against even a minority of immigrants? Or did the right very easily convince the people to accept an incredibly tenuous, unverifiable link between eeeeeeevil immigrants (or at least people who look different to me who we might arbitrarily identify as immigrants) and crimes that were supposed to be already happening? How did such crimes supposedly become caused by immigration? I have no idea and don't see any barrier to discussing it beyond there being nothing to discuss.

*And, yes, I asked the question 'How do you know they were Syrian and refugees?' and, yes, I was immediately labelled a misogynist for not being a racist, cuz they're _obviously_ immigrants, right?

The implicit part two as far as I can tell has the following logic:
1. Russian warfare via immigration against Finland is bad.
2. Therefore immigration is bad.
3. Therefore immigration of refugees is bad.
4. Therefore "silenced" (and yet ubiquitous) ab initio anti-immigration arguments are justified.

I don't think that takes a lot effort to obliterate. It's perfectly straightforward to condemn Russia's experiments with the Finnish border _and_ support helping refugees from war at the same time. This only appears contradictory if you're an extremist (i.e. have the view that immigration must always/never be supported).

On your first image btw, I'm reminded of Farage's tactics in Brexit campaigning. Photos of groups of people allegedly from abroad are no doubt extremely potent to the right wing, you guys go nuts over that stuff. They're just not all that scary to the rest of us. It's just a photo of a group of cyclists to me, and it doesn't concern me at all where they've come from.

Your second image suggests that, contrary to your assertion that people can't talk about Russian emigration, people are in fact talking about it. Even the cartoonists.

If we all just agree that, if the Russia story is true, it was a bad thing to do, does that satisfy you? Maybe do a poll? Or would that put the cancel culture fantasy too much at risk? ;)

Also see the hypothetical inflaton field, which has a constant energy despite expanding... EDIT... in a metastable state, and may do in its ground state too.

Shouldn't the second law of thermodynamics be called a "habit" instead of a law? It seems to me to speak of a tendency to disorder, not an iron-clad rule. — Manuel

Hey, if Hooke's law gets to be a law, thermodynamics is a cert!

Btw , I recall a paper Hawking gave on how multiverses _restore_ the second law, solving the problem of what happens to information about particles destroyed in black holes. Iirc, it's that over an infinite number of universes, the net loss is zero. But don't trust my ability to rc.

Yet, despite the spatial expansion, the quantum energy density remains constant, or the average micro-chaos, in lack of a better term, per spatial unit does not change. — jorndoe

QFT is valid for flat space-time only. There's no general, relativistic quantum theory, so nothing to say what happens to vacuum energy as the universe expands. Indeed, it is expected to change, but in what direction... ? E.g. https://arxiv.org/abs/1402.7049 compared with theories equating vacuum energy with the inflation field.

We have evolved already though. I am forward thinking here. — TiredThinker

That's not really the way it works. The values we have are based in large part on the qualities we evolved. Answering questions about what we'd be if eternal on the basis of value judgements of finite beings doesn't really make much sense. It would be like a hoover imagining what it would do if it could become human and deciding that it would vacuum much bigger floors. :D Also it's not really forward thinking, since you're not about to become immortal, or about to have the option. Unless you know something I don't.

Anything to back that up, or just sticking with the "probably a thing will happen"?

Anyway, if you were immortal, you'd never have evolved a dopamine response. Or indeed any response. Or indeed a central nervous system.

Surely its value is mostly in the experience of life and not the relative span of time? — TiredThinker

But what value would each experience have if we were likely to experience everything an infinite number of times? Experiences are precious only if they're... well... precious.

Except that some experiences seem to be innately preferable, and not really dictated by their rarity. A walk along the beach or in a forest, bonding with friends, watching your children play, or a truly monumental shag.

But where does those innate proclivities come from if not the finitude of life? Those innate, universally positive experiences have been hewn over millions of years because they kept our DNA thriving (the need to stay close to water and food, social cooperation, the need to care for our children or have them in the first place, etc.) And for that to happen, we have to reproduce and die.

oops! I misspoke. I have corrected my post.

It can, it's called scattering. Basically the shorter the wavelength, the [EDIT] higher the probability of scattering.

And what is a neutrino famous for? Not interacting with matter. :smile:

Which frequencies of light a material can absorb depend on the properties of that material. In the simplest case, an atom, this is determined by the energy levels of that atom. Some of those energy levels are filled, some are empty. Which depends on the state of the atom, but generally the gap between two energy levels diminishes with increasing energy, until you hit the ionisation energy of the atom.

As such, unless an atom is in a highly excited state, you green generally need higher energy EM radiation to interact with it. Most atoms are going to be transparent to radio waves simply because, whatever energy levels the electrons are at, jumping to the next one up will require more energy.

Collections of atoms such as molecules and crystals have lower energy band gaps. Water vapour appears white, for instance, because it can absorb and therefore re-emit radiation at pretty much any frequency in and around the visible range. Metals will absorb any radiation no problem because the density of available energy levels is so high.

When I first heard about the double slit experiment it gave me hope that our thoughts are more than just random electrical signals in a brain, which has always seemed too unreliable from a psychological point of view. — TiredThinker

I don't think any physicist or neurologist or psychologist believe that our thoughts are random electrical signals (if that's any reassurance). In fact, "random" and "signal" contradict one another.

So if we sent 1 photon at a time at the slits and try to detect which slit they go through it would collapse the wave function whether or not a person checks the hard drive of results to compare against the background pattern? — TiredThinker

Aye. The particle would collapse upon scattering with the photon and the pattern that would build up would be a classical double Gaussian rather than the stripes characteristic of interference.

Not a clue, sorry. Event-related optical signal (EROS) scanning measure activity at the neuron level. Might be a good place to start. Problem is, most scanning techniques excite the brain in some way, rather than measure the EM radiation it naturally emits.

Hi Enrique. It's an inverse square law. Take for example a pulse that spreads out spherically (you can extend to multiple pulses by summation or a continuous light source by integrating). The wavefront early on occupies a small surface area around the source. Later, it's further away so occupies a greater surface area. But the amount of light hasn't changed: it's just moved. So the intensity diminishes over time.

I'll just add this to the (very long) list of Mad Fool threads derailed by his own insecurities. Like I said, the historical picture you painted wasn't true. I don't really care if this has any impact on you, I'm just a stickler for facts. If you're not bothered by facts, carry on as you were. It's more for the benefit of people who might read the OP and think it was true.

You're not using reason. You've presented a historical inaccuracy. I was just pointing it out. If something didn't happen, there's nothing reasonable about insisting that it did.

[1] Nope
[2] No offense but I'll take Einstein over yourself as an authority on relativity :D
[3] My previous post treats this.

However when it comes to agency and conscious decision it gets harder to distinguish. How do I know that my sudden desire to buy an ice cream is of my own free will or pre-determined. Maybe I was deficient in calcium, it was a hot day, a new parlour had just opened that I heard about from my friend and I had just been given money and perhaps all of these factors combining simultaneously meant that my desire for Ice-cream was inevitable and always going to happen. — Benj96

It's a terminological problem. No one acts without cause: I am free to write this post however I choose, or to not write it, but I have a sufficient set of reasons and causes to choose this post. The magical definition of free will employed to counter determinism doesn't exist except as a verbal construct, a conflation of counterfactuals with reality, motivated (as far as I can tell) more by anti-determinist sentiment than actual musings of free will in the wild. You can never choose otherwise. It doesn't even make linguistic sense to assert we can.

Hi Fool. I'm not going to get into the physics so much, more the history. But one thing to mentally separate is a particular cosmological model from the theory that generates it.

General relativity itself is consistent with a static universe, a collapsing universe, an expanding universe, whatever. The particular cosmological model Einstein was responsible for was a static universe. Far from twisting and bending to make empirical evidence fit theory, Einstein referred to the (empirically, but wrongly, derived) value for the cosmological constant he used as his "biggest blunder".

GR itself was unmolested by the expanding universe. It was just that particular model that had to be thrown out.

As I understand it, the "collapse of the wave function" essentially models matter insofar as large quantities of interacting particles give rise to contexts of decoherence, resulting in definite statistical distributions relating initial and final states, beyond which the probabilities are effectively negligible. — Enrique

Well the classical limit ensures that, for the most part, material properties of large many-particle systems themselves are well defined. This doesn't mean that the particles within them have collapsed. Conducting electrons in metals, for instance, could be spread throughout the entire metal, but the metal itself still has well-defined material properties. On the other hand, as I said above, a single photon is sufficient to collapse an electron wavefunction. So it's not like there's a one-to-one correspondence between system size and collapse.

Perhaps you can explain to us how this "coherence" or quantum entanglement amongst wavicles is modeled. Local hidden variables were ruled out by experiment, so where is theory currently at in accounting for nonlocality? — Enrique

Properly by the many-particle wavefunction (the solution to the many-particle Schroedinger equation). However that is difficult to interrogate. Usually by other approximate methods then, such as quasiparticle methods in which those correlations and the "wavicle" are treated as one independent thing, or by density- or density-matrix methods where they are replicated by exchange and correlation forces. These forces are intrinsically nonlocal, but not really there, rather they're just approximations to whatever is going on in the real wavefunction. Check out modular space-time too, in which locality is pretty much redefined to not be spatial.

I was wondering how many versions of this experiment have been run? — TiredThinker

It was performed ages ago using crystals to diffract the electrons, and more recently in a way more similar to how the experiment is actually described.

Can they use an electronic eye to see and record where the photon actually goes, and half the time delete the results before a human becomes aware of it and half the time let it known to a human? — TiredThinker

Putting a light source close to the slits destroys the interference effect: the more powerful the light source, the less interference occurs. Basically the more powerful the light source, the more likely the electron will interact with one or more photons en route to the screen. So whether you look at the electronic eye's recordings or not, the photons would kill the quantum behaviour that the experiment interrogates.

I'll try, but...

Kenosha Kid is probably out making millions with his guitar rather than really important work like clarifying physics on this forum. :sad: — jgill

I wish!

It is irrefutable that only a consciousness brings the wave function to collapse. — SolarWind

This first sentence is the only thing that made sense to me, and it's not right. It's certainly refutable that consciousness collapses the wavefunction. I'd say the greatest consensus is now around non-collapse interpretations of QM (e.g. MWI). Even among collapse adherents, I don't think it's common or even sensible to make collapse dependent on consciousness. I've never met a quantum theorist who believed this, but they do, or did, exist. Personally I think that's a symptom of humans insisting on the specialness of humans though.

I think the rest of your comment assumes your own particularly esoteric beliefs.

I doubt matter underlying the wave function ever fully collapses — Enrique

Not sure what this means either. The material properties of, say, an electron (mass, charge, lepton number, etc.) certainly do transcend whatever's going on with the wavefunction if that's what you mean. Or maybe you mean the particle field. A particle is a quantised excitement of that particle field according to QFT, that is: whatever the excitation, it is constrained to have certain properties, that aforementioned material properties that are fixed, independent of the actual wavefunction.

So it is great to have Kenosha Kid, and @Prishon to fill in the blanks. — Pop

Please remember this is the internet. For all you know, I'm just frantically Googling my way through my own bullshit. And Prishon certainly is, don't elevate the guy to an authority.

I think it is largely an issue of paradigm politics. A definition of information, in this day and age, should be out there, but the one we found, which is explanatory, changes its normal meaning, and understanding as a result. Information is almost the same as interaction, in fact — Pop

Both Shannon's classical information theory and modern quantum information theory have their roots in computation, wherein the purpose of information storage is future retrieval. However, both begin with storage. Classically this could be writing something down on paper, saving something to a hard disk, memorising something, etc. In each case, one is speaking of configurations of physical things (locations of ink, polarity of little magnets, network of neurons), so classical information theory does treat information stored in a system well, it's just within a context of transmission.

Quantum information theory on the one hand is more elementary, and any review article will likely start with notion of performing a quantum mechanical measurement of a system, which is just straight QM. The information stored in that system is nothing less than the physical state of that system itself, not just the bits that were intentionally stored

On the other hand, QM is somewhat more transmission-focussed insofar as everything is geared toward an intended measurement by an experimenter (who, in quantum information theory, takes the place of the message recipient) after preparation of that system (which takes the place of sending). The observer plays a more important role in QM than in classical mechanics.

But to an extent this is linguistic. If you save a file to disk, then move that disk an inch, we have transmission of a message. Is this remotely important in talking about the information content? Not at all. Ultimately, information storage is physical configuration of state, therefore the physical configuration of a system has information irrespective of whether it was intended or transmitted. That physical state is (theoretically) completely encoded in the wavefunction (all of the information about that system), hence one can have a purely informational basis for physics.

I didn't need politeness, only careful engagement with the linked wiki page, and the definitions used there. — bongo fury

And where do you feel I diverged?

:up:

You should have paused to understand it en route. At least you'd have been exposed to more than the position operator.

Where did I state you cant get more than position from the wavefunction? — Prishon

The wavefunction contains only information about the chances where to find a particle. — Prishon

Unless you're suggesting you can get information out of the system that isn't in it to begin with...

Calling the Wigner function a fiekd I find very strange. QFT is not what we discuss now. — Prishon

Oh god. A field is a mathematical object that takes different values at different coordinates and that supports addition, subtraction, multiplication and division. Quantum fields of QFT are fields, yes. Not all fields are quantum fields. Like how all squares are rectangles but not all rectangles are squares, yes?

That's not the wavefunction. The wavefunction is a probability amplitude. The Wigner function is a probability field. You lose information going from the former to the latter in the same way you lose information going from the wavefunction to the density, or density matrix. (That said, Hohenberg & Kohn... That said, steady-state currents...)

Why are you not the one lying? — Prishon

Because I'm the one who knows that you can get more than positions out of a wavefunction maybe? Which suggests I've at least seen the time-independent Schrödinger equation.

Where did I state that? The momentum operator can too. — Prishon

Then the wavefunction doesn't merely encode position, but also momentum. In fact, the wavefunction encodes any property for which you can construct a complete basis set of eigenstates, which is why the statement:

The wavefunction contains only information about the chances where to find a particle. — Prishon

is bullshit.

I do QM in phasespace. — Prishon

Do you really mean phase space rather than reciprocal space? Then you're doing it wrong. Or, more likely, lying about doing it at all.

Honestly the first thought that came into my head when you @ed me was, "I think this guy's gonna be a waste of time." Unfortunately the second thought was "He's @ed me, it's polite to answer". My final thought is "Politeness with this guy is a waste of time." :rofl:

Almost correct. The wavefunction contains only information about the chances where to find a particle. — Prishon

I'm not going to reply to each of your daft comments, but as a physicist I guess I'm obliged to treat this. What you've just said is equivalent to "Only the position operator can be used to find expectation values of the wavefunction." Which is, of course, total rubbish.

Good point. I'll correct myself. The wavefunction is our best representation of the information about a system. A crowbar separation there between representation of a thing and a thing itself. The actual information properly belongs to the physical system itself imo, where each of its constituent parts are, not where we represent them to be, how each are moving, not how we represent their motions, what their charges, spins, masses, etc. are. How we represent it is irrelevant to what it is. Always good to demand clarity on that point.

Cool, where those states are assumed equiprobable, and in which case the analogy according to the linked Wikipedia page is that information is the _number_of messages available to... send? ... store? ... explore? ... whatever, but the cardinality of the message space. The number of alternatives. — bongo fury

Entropy is a function of the number of possible messages. Information is still afaik the content of those messages, i.e. the values of the degrees of freedom (011000100111100) rather than the number of degrees of freedom (15).

sounds like any old woo. Please explain. — bongo fury

E.g. the state space vector, wavefunction, binary readout, whatever. The thing that physically encodes the information.

Is it like, the actual message sent along a channel would have its own surprise value, its Shannon 'self-information', not specified by the source's entropy, i.e. the Shannon information of the whole message space? — bongo fury

The message space isn't the message afaik (assuming a parallel with state space -- I'm not sure I've ever used the phrase "message space" in a sentence before). The message space is a map of all the degrees of freedom of any such message. The particular message is a coordinate in that space.

Shannon information is the particular things we'd need to know about something to e.g. build a copy or predict its future behaviour. Shannon entropy is essentially the number of things we'd need to know (or rather a function of that number).

It's quippy, but it's wrong as Pop pointed out. The wavefunction is the total information about a system, that's what I had in mind.

Put it this way, is there any information-talk in physics that can't be (shouldn't be) replaced perfectly well with entropy-talk? — bongo fury

Yes. As I said above, entropy is the _number_ of microstates available to explore. The actual microstate occupied by a system would be the totality of its information, and is not specified by the system's entropy.