He's introduced as a hero. Weinberg is a hero who doesn't demand an introduction. He's done amazing physics, he's been an of import populace intellectual. He's nevertheless doing physics.
Weinberg says that from the beginning, he knew that of import physicists similar de Broglie, Einstein, as well as Schrödinger were grumpy almost quantum mechanics. It was tragic that they skipped the evolution of this exciting framework as well as its application on atoms, molecules, as well as simple particles, amidst others. But so Weinberg tried to explicate the essence of quantum mechanics as well as he found out that he couldn't exercise it to last personally satisfied. So he became some other anti-quantum zealot, we're told.
Wait a minute. Why wasn't he satisfied? One may receive got scientific or intelligent reasons to last dissatisfied as well as i may receive got unscientific, irrational, or stupid reasons to last dissatisfied. Which form of dissatisfaction is Weinberg's?
I think that the lawsuit is framed so that it's "polite" to think or at to the lowest degree say that it's the former. Too bad because it's clearly the latter, as I volition discuss.
Fine. How does he formulate his complaints? In his terminology, at that topographic point are iii principal views:
- instrumentalist
- realist
- quantum mechanics isn't quite true
Isn't it a footling disturbing that the really theorists who are most satisfied amongst quantum mechanics don't concur amongst each other what it means?This is supposed to last half-serious, half-funny. There is a full general job amongst this rhetorical format within lectures that are supposed to verbalize over serious matters. The speaker may ever retroactively reinterpret or resegregate what was meant seriously as well as what was meant as a joke.
We should convey the declaration seriously. First, it is non genuinely truthful that people who concur that the foundations of quantum mechanics are settled disagree amongst each other – they sure as shooting concur amongst each other much to a greater extent than than the critics of quantum mechanics. The latter grouping is collectively confused almost genuinely everything. Are at that topographic point many worlds? Do the worlds split during observations? During reasoning? All the time? Is Born's dominion fundamental? Derived? Psychological? Are at that topographic point extra objective positions of particles? Do they disappear during annihilation? During observation? Is at that topographic point an objective collapse? Does it occur frequently? Does it occur within protons? Does it motility extra proton decay? Invent whatever query similar that – y'all volition acquire contradictory answers from large groups of critics of quantum mechanics because their dissatisfaction is genuinely a outcome of their ignorance of modern physics as well as at that topographic point are really many ways to last ignorant because y'all may guess the answers to all the questions that y'all don't genuinely understand.
Second, fifty-fifty if y'all found many people or groups who say that quantum mechanics is settled but they would disagree almost the details of the settled principles, no, it isn't disturbing. More precisely, it sure as shooting doesn't imply that all these physicists are wrong. Almost every of import uncovering was foremost made yesteryear i scientist or a grouping that was a minority. That discoverer became sure almost the "new truth" spell at that topographic point were many other groups that nevertheless claimed to last "certain" almost their "old truth".
Heliocentrism became settled spell lots of others thought that astronomy was settled inward the geocentric way. And similar comments apply pretty much to every of import query inward the history of science. Was that disagreement disturbing? I don't know what "disturbing" means. "To disturb" is a description of subjective feelings, non some objective scientific facts. What's sure is that the mass of the scientific discoveries looked similar that as well as had to aspect similar that. People disagree almost things. That doesn't hateful that all of them are wrong.
So the existence of people who disagree amongst me almost some matters – although they also say that quantum mechanics is settled – isn't disturbing to me. They're similarly wrong as the people who say that quantum mechanics isn't settled. What's disturbing to me is that the percent of the people, fifty-fifty physics PhDs, who empathize foundations of modern physics is going down. But it's non my fault or the fault of quantum mechanics so y'all just can't rationally work it as an declaration against quantum mechanics or my explanations of that.
Then y'all start to suspect something.It's besides bad if Weinberg genuinely builds on similar šitty, sociological arguments as well as methodologies that receive got never worked. It's non scientific discipline to force far-reaching conclusions out of the existence of people who disagree amongst each other. If all people's opinions had to last "equally true", so the disagreements would last "disturbing". Well, they would last logical contradictions! But inward science, people's opinions are evidently non as true. Some statements are truthful as well as their negations are false! There is no contradiction.
It's interesting that the apparent Weinberg's supposition "all the people who disagree are as correct" sort of mimics the anti-quantum zealots' wrong understanding of the moving ridge function. They imagine that all the price inward a superposition "exist equally". But inward reality, they just force probability amplitudes for alternatives as well as exclusively one option exists – nosotros just don't know which one. The truthful cat is last or dead.
Instrumentalist approach
OK, he associates the participant approach amongst Bohr, Wigner, currently Mermin, as well as the Born rule. Weinberg says that "we desire to know what's happening out there". But this is just the criterion anti-quantum zealots' misunderstanding of the essence of quantum mechanics. Quantum mechanics says that all knowable things almost the physical organisation must last obtained through a measure whose outcomes are predicted via the Born rule. There is null else happening out there, at to the lowest degree null else knowable that is happening out there! So quantum mechanics does reply the query what is happening out at that topographic point as well as the claim that quantum mechanics is incomplete inward this sense is just a lie.
Mr Weinberg could prefer scientific discipline that says that something else is happening out there, or more things are happening out there. But this is just almost his prejudices. Not fifty-fifty Weinberg has the powerfulness to dictate Nature how She should work. Quantum mechanics speaks a clear language, it says that observations as well as the corresponding collapses are the exclusively things that are genuinely happening out there, as well as the theory is hence consummate inward this sense. Weinberg's psychological dissatisfaction just isn't an declaration against the validity or completeness of quantum mechanics. To regain a job amongst a well-defined theory, y'all demand to falsify it. For example, Weinberg may attempt to falsify the claim yesteryear quantum mechanics "that exclusively results of observations exist" yesteryear observing something that isn't a outcome of an observation! Good luck amongst that! ;-)
His 2nd electrical load is that these laws of quantum mechanics aren't impersonal as well as they should be. We wanted such impersonal laws ever since Newton. Now, what is the right response to this complaint? It depends on the pregnant of "impersonal". Quantum mechanics sure as shooting has no dependence on humans – on the adult man sapiens species amongst the iv limbs as well as 23 pairs of chromosomes. So to say that it is "human" or "anthropomorphic" inward this sense would last a lie.
On the other hand, quantum mechanics requires a perspective, unremarkably identified amongst an observer. Influenza A virus subtype H5N1 perspective that allows to define what the observations are as well as what they results were or volition be. In the normal worlds, the application of quantum mechanics requires an observer. If this is plenty for y'all to say quantum mechanics "isn't impersonal", well, so quantum mechanics "isn't impersonal"! It is "personal", if y'all wish, because it needs an observer to last applied. The observer may last a smart beast or an extraterrestrial robot – as well as less usefully, it could fifty-fifty last a large molecule (it's less useful because the molecule unremarkably doesn't know how to bargain amongst the information intelligently). But an observer is needed.
Is that a "problem" of quantum mechanics that it is "personal", as well as hence "less impersonal" than what Isaac Newton hoped for? You gotta last kidding, Dr Weinberg, right? Isaac Newton was just wrong – his theory wasn't the finally discussion – when it came to these questions. Is that so shocking that Isaac Newton's words weren't the finally ones? Isaac Newton also wanted laws amongst the absolute fourth dimension as well as absolute infinite – as well as inward fact, he described those as religiously as the "impersonal nature" of the laws. The absolute infinite had the spirit flight everywhere. Relativity showed that simultaneity was relative. Can nosotros conclude that relativity is wrong because it contradicts some "ideal" that Isaac Newton had? Are y'all serious? Do y'all genuinely desire to define scientific discipline as the eternal worshiping of Isaac Newton's views as the finally word? Because that's exactly what y'all seem to last saying.
Quantum mechanics just is "personal" inward the sense that it requires observers – inward the role of axioms, it depends on pre-existing information almost the nature as well as outcomes of observations that are extracted through subjective perception. This "personal" is an as established describing word as "heliocentric" or "evolutionary". People who say that the Solar System should last "geocentric" or the origin of species should last "creationist" or the laws of physics should last "impersonal" are just wrong. To declare that the laws must last "impersonal" inward the sense of independent of observers is an indefensible – as well as for to a greater extent than than ninety years disproven – dogma that is totally analogous to the claim that the Solar System has to last geocentric as well as the species were created inward a week. You tin give the axe say as well as demand geocentric, creationist, as well as impersonal laws but it just shows your stupidity as well as bigotry as well as it doesn't thing whether y'all got Nobel prizes. Science knows that the right adjectives are "heliocentric", "evolutionary", as well as "personal" amongst these definitions.
David Mermin tells Weinberg that these features don't bother him – but they bother Weinberg, nosotros heard. They don't bother me, either, because at that topographic point is just no tension betwixt the predictions of quantum mechanics (logical, internal tension or tension amongst observable facts). I think it's obvious that the argue behind the "bothering" is null else than an irrational prejudice. There's no departure betwixt the "bothered Weinberg" as well as the "bothered Inquisition" that just disliked the heliocentric models or the Christians who hated evolution. There's no logical as well as scientifically valid way to justify either of these dissatisfied sentiments.
Realist approach
In this section, Weinberg repeats some delusions held yesteryear the many-worlds ideologues. The realist interpretation automatically leads to "many worlds". Well, that's rubbish. The mathematics of Schrödinger's equation implies i moving ridge role that is evolving inward time. There is absolutely no natural, unique, or canonical way to split upwards the moving ridge role to many price (there is a hugely infinite unwrap of ways to decompose a lay down vector into a sum) as well as that's why it's completely wrong to say that the unmarried moving ridge role describes "many worlds".
It's nevertheless a unmarried moving ridge function. In proper "instrumentalist" quantum mechanics, it's a unmarried moving ridge role remembering all probability amplitudes for all possible outcomes of measurements inward the unmarried world. When an observation is made, the moving ridge role abruptly changes – collapses to an eigenstate of the just measured observable. Certain folks desire to deny this discontinuity associated amongst the measurement. These "many worlds" people throw the exclusively physically feasible interpretation of the moving ridge role to the trash bin – so what they're left amongst is a mathematical equation from quantum mechanics, but without whatever usable connective to Earth to a greater extent than or less us.
It's completely idiotic to deny that the moving ridge role has to modify inward the wake of an observation.
OK, Weinberg totally uncritically repeats lots of delusions yesteryear the many-worlds ideologues, e.g. that the "many worlds" unavoidably follow from Schrödinger's equation – which is consummate nonsense, as I receive got mentioned. He also remains completely still almost dozens of other problems amongst this ideology. For example, he does call that Schrödinger's equation should last linear but the wave-function-like-another-classical-wave pictures don't receive got the slightest justification for the linearity of the equation. He isn't bothered. In this case, a scientist must last bothered because the nonlinearity of the equation is genuinely a generic prediction of that "realist" motion-picture exhibit that is slow to last falsified experimentally. (There's no known way to falsify the claim yesteryear quantum mechanics that the theory is "personal".)
Influenza A virus subtype H5N1 positive thing is that Weinberg realizes at to the lowest degree i thing – that at that topographic point is no way to derive the Born dominion from that picture. In fact, he seems to empathize my favorite observation that at that topographic point tin give the axe never last such a derivation because the proffer proverb "the probability is given yesteryear a specific formula" must appear at a sure moment. In a derivation, it can't appear spontaneously – so at that topographic point has to last an axiom that says something almost the value of the probability. There has to last something similar Born's axiom somewhere or another, equivalent or to a greater extent than complex, axioms of the same kind. All the people who believe that Born's dominion may last derived noncircularly from null can't add together 2 plus two.
Weinberg is also bothered yesteryear "too many worlds", an aesthetic problem. Sure, "too many worlds" would last ugly but as I receive got mentioned, it's just wrong to say that a unmarried moving ridge role "splits" to many worlds. There's no (and at that topographic point tin give the axe last no) well-defined dominion to dictate what such a split should be. There's also no job that would last "cured" yesteryear such a decision as well as no other evidence that such a splitting takes place.
Objective collapse
At 13:35, he reveals his foremost proposed "kind of modification of quantum mechanics" that he would similar to see. Influenza A virus subtype H5N1 superposition \(\alpha\ket{\uparrow}+\beta\ket{\downarrow}\) should spontaneously modify to \(\ket\uparrow\) or \(\ket\downarrow\) afterward some time. It's some generalized "objective collapse" or Ghirardi-Rimini-Weber picture.
Now, why would he believe such a thing? Why would he consider such a modified theory superior? Or "beyond quantum mechanics"? The complex superpositions are clearly an of import novel concept inward quantum mechanics – just similar the relativity of simultaneity inward the special theory of relativity. What's going on is that Weinberg clearly has a deep psychological job amongst the very existence of superpositions. That's shown yesteryear the fact that he would consider a theory without superpositions – as well as fifty-fifty a theory that gradually erases superpositions – to last superior.
This take in is absolutely irrational. It's the geocentrism in i lawsuit again. Indeed, a postulate of quantum mechanics is that all superpositions of a collection of states are as allowed as the private states inward the collection themselves. The infinite of allowed states is a linear complex Hilbert infinite – a vector infinite closed nether add-on as well as linear combinations. I would claim that this isn't fifty-fifty something that the misinterpreters of quantum mechanics could receive got started to obfuscate. The linearity of the Hilbert infinite of allowed pure states is a totally simple belongings of the whole formalism. You can't receive got anything similar to quantum mechanics without that linearity of the Hilbert space.
Imagine that a superposition of "up" as well as "down" gradually drifts either to "up" or "down". Why would he consider it better? Influenza A virus subtype H5N1 superposition of "up" as well as "down" for an electron's spin just describes the spin polarized along a full general axis inward iii dimensions. Take this axis \(\hat a\). Why should the axis of electron's spin spontaneously approach \(\hat z^+\) or \(\hat z^-\)? What is so special almost the \(z\)-axis? Clearly, such a drift would interruption the rotational symmetry of the laws of physics. Noether's theorem makes it clear that it would interruption the angular momentum conservation law, too. And indeed, if a nonzero probability of having the angular momentum "down" could all of a abrupt disappear, it would correspond to a violation of the conservation law, or at to the lowest degree a "nonzero probability of such a violation".
Such a modification of quantum mechanics would motility infinitely many similar problems. The existent job is that at that topographic point is never whatever preferred lay down of the Hilbert infinite describing a generic complex plenty physical system. One can't genuinely split upwards the Hilbert infinite to "superpositions" as well as "non-superpositions" (i.e. preferred lay down vector) just because at that topographic point isn't whatever preferred lay down of the Hilbert space. The whole Weinberg's way of reasoning is totally wrong – it's a full-blown anti-quantum zeal. To receive got a telephone substitution job amongst superpositions way to last a full-blown anti-quantum zealot. Superpositions are clearly as vital inward quantum mechanics as a frame-dependent fourth dimension coordinate inward special relativity. If y'all can't convey these rudimentary features, that's besides bad but your existent understanding of these theories is fountain to last null inward that case. At most, y'all may pretend that y'all empathize these theories. But because y'all don't genuinely believe what y'all say, y'all don't actually empathize them.
But imagine that at that topographic point are some laws that force the superpositions towards some preferred basis, which y'all assume to be (although it cannot). What would y'all gain out of it? Why would y'all consider such a theory ameliorate or to a greater extent than satisfying? It nevertheless makes absolutely no sense whatsoever. The resulting theory would last some foreign hybrid of classical physics as well as quantum mechanics that would incorporate the puzzling features as well as inconsistencies of both frameworks.
You know, at to the lowest degree inward the brusk run, when a molecule evolves, y'all clearly demand to allow the full general superpositions. We tin give the axe verify that afterward some time, molecules may last found inward all superpositions – the corresponding probabilities of outcomes exactly jibe the conjectured superposition state. If y'all (irrationally) associate superpositions amongst some "ugliness" or fifty-fifty "potential inconsistency", well, so Nature has this "ugliness" as well as "potential inconsistency", at to the lowest degree at brusk distance scales as well as fourth dimension scales, because the relevance of superpositions may last straight experimentally observed. If y'all club superpositions to "fade away" afterward some time, great, but they are nevertheless non eliminated from the laws of physics.
Weinberg spends a lot of fourth dimension inward his verbalize yesteryear talking almost some Ghirardi-Rimini-Weber collapses. He often stops yesteryear proverb that he doesn't know whether some numerical value of an loose energy scale or some other parameter is OK or not. He in all probability doesn't desire to know! If he did proper science, similar he managed to exercise hundreds of times inward his life, he could speedily conclude that null tin give the axe piece of work good inward these theories.
If some Ghirardi-Rimini-Weber "spontaneous collapses" of the moving ridge functions are besides frequent, besides vigorous, affecting besides many fountain states etc., so the theory would predict novel "flashes" as well as novel types of a radioactivity that don't exist. So all these parameters must last pushed to weak or otherwise unobservable corners. But when they're unobservable, they volition lose the powerfulness to modify anything almost the pregnant of quantum mechanics, too. Small plenty objects evolving for brusk plenty times volition evolve just similar inward quantum mechanics. You volition demand the same superpositions as well as the same demand to translate the superpositions probabilitically.
Influenza A virus subtype H5N1 really specific example: Imagine that y'all assume, similar Weinberg in all probability does, that at that topographic point is something wrong almost quantum mechanics because it allows the encephalon to last inward a superposition "I saw an explosion" as well as "I saw no explosion". Influenza A virus subtype H5N1 generic initial pure lay down evolves to a superposition. You either convey it as well as acknowledge that the probabilistic interpretation of the superposition is needed to explicate why y'all exclusively had i of these feelings; or y'all innovate modifications that are strong plenty so that they mess upwards amongst your encephalon earlier the realization as well as motility some explosion themselves. What are these novel explosions? It's something that produces at to the lowest degree a chip of novel uncertainty (or an erroneous bit) per a kilogram of the encephalon materials as well as per 2nd – otherwise it couldn't "cure" the superpositions inward time. But that's clearly a fast plenty novel procedure that y'all just could regain otherwise if it existed.
You just can't swallow a cake as well as receive got it, too. Either y'all modify quantum mechanics so that your novel theory produces novel effects inward the currently observable best experiments – inward which illustration you're screwed because QM has worked perfectly inward all of them which excludes all the modifications. Or your modifications of quantum mechanics volition last so weak that the whole experimental province of affairs volition last described yesteryear laws that are effectively indistinguishable from quantum mechanics – so the modifications can't assist to solve the (psychological) "problem" that y'all receive got amongst quantum mechanics.
What Weinberg as well as other "modifiers" of quantum mechanics doesn't seem to empathize is that his psychological problems amongst quantum mechanics aren't almost some details. They're almost the mass of quantum mechanics, almost O(100%) of the theory. That's truthful for the value of the predictions as good as the states themselves – he has a job amongst "superpositions" as well as almost all vectors inward the Hilbert infinite are "superpositions". If he has a job amongst O(100%) of the theory, he can't cure this job yesteryear changing the theory yesteryear O(0.00000000001%). Small corrections just can't last plenty to laid his job – these 2 things receive got a totally unlike magnitude. He has to modify quantum mechanics yesteryear a huge amount, yesteryear O(100%), as well as so he gets a theory that is inward a totally obvious disagreement amongst the observations, just similar fundamentally non-relativistic theories contradict tests of relativity as well as fundamentally creationist theories contradicts tests of evolution. Your alternatives are totally hopeless.
All the anti-quantum zealots are constantly fooling themselves, trying to last persuaded that their totally qualitatively, game-changing modifications of quantum mechanics miraculously allow the theory to piece of work just similar before. But that's consummate nonsense – a sign that this motility has turned into a organized faith that has abandoned all rationality. They're similar a creationist who hates evolution. So this creationist may last shown some "micro-evolution" afterward a few generations. It's an experimental fact but he tries to "confine" this fact as well as fighting that inward the long term, the origin of species is genuinely governed yesteryear creationism (this creationist illustration is genuinely as existent as the anti-quantum zealots). Similarly, a hater of relativity mightiness say that afterward a footling while, some effects accommodate all the clocks as well as restore the universal fourth dimension for everybody. Influenza A virus subtype H5N1 geocentrist could say that afterward a year, the illusion that Mars orbits the Dominicus volition become away as well as Mars volition start to orbit the lay down as it should.
How could the hybrid theory work? It cannot. And what would i gain from a theory that industrial plant similar evolution inward the brusk term but reduces to creationism inward the long run? Nothing. If at that topographic point is something conceptually ugly or bad almost evolution, this hybrid theory would nevertheless receive got this ugliness! On transcend of that, it would last a mixture of totally unlike theories. Weinberg's proposed modifications of QM are as stupid as my other examples. He's clearly prejudiced as well as prefers whatever modification of physics that makes it "less quantum" according to some sentiments. But this clearly proves that he is non driven yesteryear whatever rational or meritocratic criteria at all. He is on a mission that starts amongst the commandment "quantum mechanics is bad as well as y'all volition ever spit on it as well as invent arbitrary fog as long as it makes quantum mechanics aspect bad". There tin give the axe be no other justification for his efforts.
So his Lindblad equations that I receive got previously discussed are an illustration of this totally misguided, quasi-religiously motivated anti-quantum effort. You may generalize the evolution equation for the density matrix to a Lindblad equation yesteryear making some additional parameters nonzero. But proper quantum mechanics is nevertheless a special illustration of your novel theory. It way that the amount of difficulties y'all receive got to clarify – as well as the amount of psychologically unpleasant things – couldn't receive got decreased yesteryear adding the novel Lindblad terms.
Around 18:00, he discusses locality as well as entanglement as well as says that y'all tin give the axe "change psi at the distance but non rho at the distance". This is a sloppy way to limited a valid call for but a really sloppy as well as misleading way, indeed. What he way is that the reduced density matrix for the subsystem B isn't changed yesteryear the measure of subsystem Influenza A virus subtype H5N1 – assuming that y'all don't larn the outcome of the measure of A. I receive got given the proof many times. This is a way to exhibit that the laws of quantum mechanics are local.
He says that "you tin give the axe modify the moving ridge role at a distance". These sentences arrive audio as if the "density matrix" laws were to a greater extent than local than the "wave role laws". But that's ludicrous, of course. The evolution laws governing the density matrices as well as moving ridge functions are exactly the same – they tin give the axe last derived from i another. So the departure betwixt the apparent "degrees of locality" isn't betwixt pure as well as mixed states. Instead, it is betwixt reduced as well as non-reduced states. And due to entanglement, the mixed states are needed to define a reduced state!
It way that mixed states are needed to verbalize over the properties of subsystems separately (we demand to calculate the reduced density matrix, as well as there's null such as a reduced pure vector for a generic – entangled – lay down of the composite system), as well as hence mixed states are needed to straight exhibit that measurements don't deed at a distance.
It doesn't hateful that inward price of pure vectors, the measurements deed at a distance. Instead, the "defect" of the pure states is that they don't allow us to verbalize over subsystems separately at all! (At i moment, Weinberg also makes the beginner's fault as well as talks almost the moving ridge functions of private particles. Sorry, there's exclusively i moving ridge role for the whole organisation – inward principle, for the whole Universe. There aren't "many" moving ridge functions for parts.) So pure states are a "wrong language" to verbalize over locality inward general. They don't show nonlocality inward whatever sense.
Before 20:00, Weinberg says a lot of additional confusing things almost the human relationship betwixt the pure states as well as mixed states. He discusses the possibility that the "density matrix could last something to tell us something almost the pure state" as well as so on. But all these ideas arrive clear that he nevertheless assumes that the moving ridge role is a collection of classical degrees of freedom. But it is not. The moving ridge role as well as the density matrix play a totally analogous role: they incorporate all the probability amplitudes (and hence the probabilities) of outcomes of whatever measurements that are knowable almost a physical system.
When the observer has the maximum precise noesis allowed yesteryear quantum mechanics (including the uncertainty principle), e.g. when a consummate laid of commuting observables was just measured, the organisation is described yesteryear a pure state. When there's some additional uncertainty, the organisation is described yesteryear a mixed lay down i.e. a density matrix. Both possibilities are as "real" as well as as "possible". It is completely wrong to imagine that the density matrix is a generalized probability distribution spell the pure lay down is to a greater extent than existent or objective. They're as probabilistic. Both psi as well as rho are complexified quantum generalizations of the concept of probabilistic distributions.
I said that fifty-fifty if the extra Lindblad coefficients generalizing Schrödinger's equation were found to last nonzero, they couldn't perchance "clarify" anything almost the aspects of quantum mechanics that Weinberg calls dissatisfying. But I think it's genuinely pointless to aspect for such coefficients. They can't last nonzero. One simple way to meet it is that inward principle, every physical organisation may last brought into a pure state. There's no way to derive an "equation for a pure state" from the Lindblad equation for the density matrix. So the Lindblad deformation would hateful a pure-to-mixed evolution. That would amount to information loss. If that existed inward principle, nosotros could genuinely regain it all the time. The probabilities would leak almost everywhere. An atom couldn't conserve its angular momentum for besides long. But it does conserve it. So y'all genuinely demand the angular momentum to receive got a special human relationship amongst the fourth dimension evolution – it must commute amongst the Hamiltonian as well as the Hamiltonian has to tell the total story almost the evolution.
Just similar there's no Schrödinger's equation for a pure lay down corresponding to the Lindblad equation for the density matrix, at that topographic point could last no Heisenberg picture, either. We couldn't say that the observables themselves are evolving. There would last no Feynman's formulation of such a theory, either. Even if y'all believed that those deformations aren't an inconsistency, why would y'all think that they are an improvement of anything?
You know, inward theories nosotros use, nosotros receive got e.g. the algebra \(SU(2)\) of rotations generated yesteryear the angular momentum. The iii generators just commute amongst the Hamiltonian. The commutators are just zero, it's pretty as well as clean, it agrees amongst everything, the evolution as well as rotation transformations are exactly given yesteryear the generators. Weinberg wants to pollute these things yesteryear some extra deformations. Why would he think that the newer theory would last to a greater extent than satisfactory or "better" inward whatever sense? It makes no sense. It would last polluted as well as less consistent. The unwrap of problems (or perceived problems) could exclusively increase.
At 24:00, Weinberg says that "atomic clocks aren't clocks – they are frequency standards". That's silly. Atomic clocks sure as shooting are clocks, "clocks" as well as "frequency standards" aren't mutually excluding inward whatever way, as well as all clocks that receive got the best precision at a given minute of fourth dimension receive got been used as "frequency standards". To some extent, "good clocks" as well as "frequency standards" are synonymous.
OK, Weinberg wants to work some atomic clock to regain the nonzero Lindblad coefficients. Too bad, he doesn't desire to consummate the calculation to meet whether the parameters may last both measurable yesteryear his method as well as relevant to "cure the alleged problems" of quantum mechanics. Clearly, the reply is No.
At 34:00, he promotes Roger Penrose's totally irrational claim that gravity collapses the moving ridge function. You know, "pieces" of a moving ridge role bundle aren't 2 objects. They are alternatives for 2 possible locations of i object. So they cannot gravitationally attract each other because "their" existence is mutually exclusive. The gravitational acre to a greater extent than or less a truthful cat depends on (is entangled with) the cat's beingness last or dead. So the gravitational acre is found inward a superposition of possibilities, too. Penrose's gravitational-psi-collapse are pure crackpottery.
More generally, Weinberg asks what distinguishes microscopic as well as macroscopic systems. You tin give the axe meet that it's the same frantic endeavour to "contain" quantum mechanics – just similar the creationists desire to "contain" evolution. The large motion-picture exhibit has to last classical as well as creationist. Sorry, at that topographic point is evidently no universal way to define a boundary betwixt microscopic as well as macroscopic systems. Even if y'all found such a boundary, it would last irrelevant because quantum mechanics applies both to "microscopic" as good as "macroscopic" objects! This is genuinely a declaration totally analogous to the proffer that Darwin's theory industrial plant for "microevolution" as well as "macroevolution", too. Only bigots are obsessed amongst the efforts to trim the applicability of evolution or quantum mechanics. Bigotry is the exclusively justification of such efforts. There is no rational justification.
At 34:30, Weinberg makes a "groundbreaking" observation that macroscopic systems receive got exponentially unopen loose energy levels. It's been understood from Day One of quantum mechanics. In fact, the argue why the unopen levels receive got something to exercise amongst the classical bound was understood yesteryear Bohr five years earlier the nascency of quantum mechanics – it was called the correspondence principle. Bohr clearly articulated it inward 1920 but he had already used it inward the old model of the atom inward 1913. But the correspondence regulation is a way to meet why an approximate, classical theory industrial plant as a usable plenty approximation. It is not a way to heighten doubtfulness almost the validity of quantum mechanics.
I think it's terrible when people attempt to audio master copy yesteryear vaguely talking almost totally criterion things that receive got been known fifty-fifty before quantum mechanics was born, 100 years ago, as well as they were understood correctly pretty much right away spell the vague babbling of Weinberg's exclusively has the finish to spread some wrong understanding of the nearby levels.
Needless to say, the exponentially tiny separation of loose energy levels is something that subfields of quantum mechanics work all the fourth dimension today. People doing dark hole information puzzle are extremely aware of the exponentially fine spectrum of dark hole microstates – as well as what it way for the representation of diverse operators etc. It's been discussed inward quite some exceptional on this blog, too. Why would Weinberg believe that some vague comments that the dense levels could perhaps receive got something to exercise amongst the emergence of the classical bound are insightful? They're non insightful at all as well as the amount of evidence (hiding inward the fine levels) that at that topographic point is something incomplete almost quantum mechanics is zero. If y'all give a verbalize where A,B appear inward the same sentence, it does not hateful that Influenza A virus subtype H5N1 implies B.
His finally judgement is that physics demand a guiding regulation how to become beyond QM – that would tell us to a greater extent than than the full general principles. Well, nosotros exercise receive got such a guiding principle, it's the full general postulates of quantum mechanics. And everything he does just violates this guiding principle.
In the foremost question, Weinberg says that neutrinos are non useful for his efforts. In the 2nd question, Weinberg says that he's non Penrose as well as gravitons are useless for his efforts. The 3rd query asks why the absence of superpositions doesn't dominion out "realism". Weinberg makes some wrong statements that nosotros ever receive got to calculate amongst "ensembles of pure states". It's just non true. We may calculate amongst mixed states directly. Or without states, inward the Heisenberg picture.
He repeated the right comments that the many-worlds receive got to add together a Born-like axiom, anyway. Then he laughs when he asks: "Would at that topographic point last no Nature without people or physicists?" Sorry but quantum mechanics is a universal theory of the Universe as well as everything inward it. So inward principle, observers are needed to meaningfully apply QM to any question, including those almost the Universe as well as its long-term evolution. You misunderstand the large motion-picture exhibit if y'all regain this fact laughable. This laughing is the same stupid mocking as when creationists at our college laughed that Darwin predicted a plane to modify to a squirrel spell sitting on a tree. Well, non really. Darwin made predictions that agreed amongst all our observations, e.g. that nosotros don't meet a realtime transmutation of birds into squirrels. But inward principle, changes similar that do occur inward the long term, whether y'all similar it or mock it, as well as inward the same way, quantum mechanics demands observers for a precise formulation of all questions, including questions almost the long-term evolution of the Universe or the unwrap of spiral arms of a galaxy. The information almost the specific unwrap of spiral arms doesn't "exist" inward whatever scientifically meaningful way if at that topographic point is no observer. Period. To express joy hither way to exhibit one's ignorance of modern physics.
At 40:50, 't Hooft asked a query that was genuinely an incoherent statement. He wants to say that all the laws are the same they receive got ever been, nosotros just don't know the initial state. As I mentioned many times, he genuinely ceased to empathize quantum mechanics completely – e.g. the existence as well as pregnant of the relative phases. His resolution (I hateful the fineness of his analysis) is just so bad that he no longer distinguishes a diagonal density matrix from a pure superposition state. Weinberg says that he has no overlap amongst 't Hooft's thinking as well as repeats that Born's dominion needs "people" which is nonsense. Weinberg agrees amongst 't Hooft that all problems amongst Born's dominion could last explained yesteryear the ignorance of the initial state. That's non bad but this motion-picture exhibit of theirs cannot brand quantitative predictions of the probabilities spell proper QM tin give the axe – so theirs is clearly an inferior theory. Well, non a competing theory at all.
It's just frustrating to meet these Nobel prize winners as they verbalize over some totally basic undergraduate cloth from quantum mechanics just similar 2 confused, mediocre undergraduate students would afterward the 3rd lecture of an undergraduate course.
I am afraid that we're entering a nighttime historic catamenia as well as when it's over, perhaps inward the 22nd century, the hereafter historians volition analyze what volition receive got gone wrong inward the early on 21st century as well as whether it was possible to halt the collapse of the mankind's discourse into a bunch of medieval superstitions. They volition know that the evolution was linked to the post-truth era, endlessly softening educational activity as well as Academia, as well as politically right taboos. Weinberg could receive got stopped as well as was expected but genuinely helped the mankind to sink deeper into this profoundly irrational antiscientific bigotry.