Lattices and Lorentz invariance

No, you've completely misunderstood my perspective of things. It's because I am familiar enough with mainstream theories to know that they are supported by not just one or two experiments, but countless thousands of them, and quantitatively. The mathematics of mainstream theories are effectively summaries of entire domains of experimental results. That is why it is extremely suspicious that you keep wanting to ignore existing mathematical models in favour of just looking at a mere handful of experiments, and even there you don't even show that you can get the numbers right.

I think it is you here who doesn't grasp just how well supported existing theories are, and how high the bar is if you want to propose anything new. Just picking a handful of experiments and coming up with qualitative explanations for them, which is what you're always doing, is trivially easy by comparison with what mainstream theories actually have to accomplish.

And the universe is necessarily literally as simple as what you see?

No it doesn't.

No, my reflex here is to google the phrase "quasi spherical harmonic" and glean what I can from e.g. the sort of article that turns up. Just from the abstract:

In short, whatever they are, it is clear they are not what one would normally consider a spatial function. If you know anything about spin half you would know that something like this is inevitable: for instance spin half states have the rather unusual mathematical property that under 360 degree rotations, they get an extra minus sign. While this in itself is not a problem in quantum physics (because that extra minus sign gets squared away when you actually go and calculate a probability), it is going to be a problem if you try to construct a spatial wavefunction with that property. Obviously the only complex valued wavefunction that has that property is \(\psi(r,\, \theta,\, \varphi) = 0\). That is no doubt where the issue of quasi spherical harmonics being "double valued" comes from, or the need to define them over a range of angles twice as large as the entire sphere. Intuitively, changing sign after a 360 degree rotation isn't a problem if you're happy to play with the idea of defining a function over a range of 720 degrees.

That description doesn't fit with anything I know about spherical harmonics.

No, what you explained above is exactly what I meant: the Einstein-de Haas experiment does not show that spin is a special case of orbital angular momentum, and specifically that idea is what doesn't work in quantum physics.

Technically it is: every point on the rotating Earth's surface is orbiting the Earth's centre of mass. That is where the name technically comes from. Spinning tops and the rotating Earth both have the type of angular momentum that we call "orbital angular momentum". That's just the terminology we use.

So what's wrong with it? It seems like a pretty good argument to me.

Though I don't know why you're bringing this up, since I am not even using that argument.

No it doesn't. It means that the sum of all orbital angular momentum and spin always stays the same. That is what the Einstein-de Haas effect shows, and that is the sense in they can be said to be "of the same nature".

How much time do you need? You are citing experiments that were performed 90 years ago.

I am backing up my arguments with references to mainstream theories, which between them summarise the results of just about every experiment that has ever been performed. Your references to experiment < the entire history of experimental physics.

 

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The negative sign in your example is a result of choosing the zero point to be in a funny place, the positive direction to be an unusual choice and the fact that displacement is not a scalar, but a vector quantity. If you wanted you could write down a vector in an arbitrary coordinate system using a rotation matrix. The point is negative measurements of displacement are perfectly real and reasonable.

The pedant in me is forcing me to point out you don't refer to zero degrees Kelvin. The term is zero Kelvin.

I also think you're getting confused about absolute zero. Due to quantum mechanics it is impossible to realise this temperature because there is always a ground state that has non zero energy. I'm reluctant to make a pronouncement about what would happen to magnetism at absolute zero, but I suspect it would not happen.

It does seem like that to start with, but time truly is a more fundamental object than entropy, but entropy provides time with an experimentally measurable direction.

My point is your notion of "real" is very limited indeed.

With my mod hat on I can say that the rules apply to everyone equally and you must also be aware that there are actions being taken that you wont necessarily know about.

That doesn't come close to answering the question which was: Why does the sign of the time component of the metric mean you can't travel backwards in time?

It's still a logical fallacy by making an appeal to authority. Do you think you can try making an argument without referring to a famous physicist and how his / her work now confirms what you advocate?

Again, you're having problems because you are trying to oversimplify things without truly understanding the fundamentals. To start with, that quote is a pop science description of QFT - why bother with it when it will distort what QFT is saying, as we don't have access to quantum intuition. A quantum excitation is not a ripple at all, the key word in that quote is "chunked."

Diffraction is a result of a lot of photons passing through the experiment and the wavefunction provides a probability for it to be detected at various points along the screen. A single photon does not diffract really, because it is a particle.

I don't think any classical description of spin will give you a notion of the spin of a particle. That's kind of the point of quantum mechanical spin.

Allow me to repeat your quote adding a small highlight
"In standard physics, Lorentz symmetry is "the feature of nature that says experimental results are independent of the orientation or the boost velocity of the laboratory through space"

invariance under changes in orientation is exactly the invariance under rotations I have been talking about.

But you're referring to spacetime (or space, whatever) as a lattice and you can't rotate spacetime - you simply rotate the experiment relative to space. In a continuum theory that's no problem because there is Lorentz invariance, but in a theory on a lattice rotational symmetry is reduced to a discrete subgroup. This is a well known problem for people that use lattices to solve problems, and a great deal of care has to be taken to make sure Lorentz invariance is restored in the final answers. Go back and read what I wrote - Lorentz invariance contains boosts and spatial rotations. Once you've done that it would probably be a good idea to actually learn some proper relativity.

No, it makes no sense whatsoever.

 

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I haven't misunderstood you pryzk. I mean that sincerely. And our conversation here has helped me to understand you better.

The sort of things I talk about are old things, not new things. I'm not some "my theory" guy. But when I refer to say Maxwell's screw or The Forgotten Legacy of Godel and Einstein, nobody knows what I'm on about.

Some things are.

Oh yes it does.

It's something like a moebius strip. One rotation is twice the rate of the other, so you have to go round twice to get back to the same position and orientation.

Noted.

We'll see.

Noted.

It employs a billiard-ball concept of an electron instead of allowing for a compound wave rotation.

And that means there's something going round in there.

About three years.

IMHO you're exhibiting a bias against experimental evidence when it appears to challenge some concept that you believe to be supported by theory. I hope I'm helping you with this.

 

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Distance is a scalar, displacement is a vector. See http://www.physicsclassroom.com/class/1dkin/u1l1c.cfm . There really is no such thing as a negative distance.

Sorry. My mistake.

A subatomic particle like an electron doesn't have a temperature. Temperature is an "emergent" property of a system's aggregate particle motion.

There is no actual "arrow of time" in some system, such as a container of ideal gas. Just atoms moving. The motion tends to even out. Then there's no hotspots, it's all lukewarm, entropy is at a maximum, and there's no available energy. Entropy is essentially sameness.

It is. When somebody mentions something familiar that you take for granted, check yourself. Ask yourself if you can actually see one of these things. With practice you get better at distinguishing reality from abstraction.

OK noted. Sorry I have to go. I'll look at the rest of your post later.

 

A quickie continuation:

It doesn’t. Look again at the simple inference of time dilation. Imagine you’re the moving twin, where we end up saying your light followed a zigzag path like this: /\/\/\. Break that down into a series of right-angled triangles. The spacetime interval is derived from the length of all the hypotenuses. Your motion in the x direction is represented by the base of the triangles. The height represents the time dilation factor. The thing you call time t is represented by the number of triangles. You can’t travel backwards in time because you don’t even travel forwards in time. All you’re doing is counting triangles. The “forward direction in time” you think you’re travelling in is just a counting direction. And there’s no such thing as a negative distance, and no such thing as negative motion. So regardless of how you move and no matter how light moves, you cannot count a negative number of triangles, and you cannot reduce your count so far.

 

Is this what you tell yourself to convince yourself its okay you can't do any mathematics? That its okay you don't and can't read any textbooks? That it's okay all you can do is read pop science books written by people like us to tell you of the work by people like us to understand the experiments done by people like us?

If you can't do the details then you must accept people's word for things, even when you don't understand it. For example, you clearly don't understand curvature so all you know of it you've had to just accept from what other people have written and you've then read. You then just make up interpretations due to that lack of understanding. If you could actually do the details you could convince yourself of the results step by step. I personally get it all the time, I read some overview of something and think "How the hell is that true?". I then sit down and work through the calculations myself, comparing with the work, and end up seeing how it's done and I then understand the result, rather than just parrot it.

You complain we might be too close but you're too far. You don't do experiments, you don't have experimental data, you don't know theory, you can't do theory, you don't understand theory. So what have you got? Your interpretation of a wordy summary of a complicated topic you haven't learnt.

And you seriously think you're in a position to have 2 cents worth listening to?

 

There's nothing weird about it once you stop thinking billiard balls. How anybody can think for a moment that the electron is some rotating charged mass in the light of pair production and annihilation absolutely takes my breath away. In similar vein the experimental size of the electron isn't that. It's an upper limit in a failed search for an internal structure. It's like probing for a cannonball in a whirlpool, and then declaring that the electron can be no bigger than a ping-pong ball because you'd have otherwise felt it. The point about spin obeying quantum rather than classical rules is more of the same billiard-ball logic.

Fair enough.

Sounds reasonable.

Run that by me again: what's matter made of?

But it still reflects the view that 'spin' in quantum systems doesn't involve any actual rotation. This isn't just some pop-science view.

I'm challenging the view that spin angular momentum has nothing to do with rotation and is a purely quantum mechanical phenomenon. It isn't just some pop-science view, and I'm afraid it isn't actually supported.

I've explained this already. But for your sake: it puts up a straw-man argument suggesting that an electron is a solid rotating body like the earth, then says it would have to be rotating faster than c for this, then says thats impossible, ergo there's no real rotation of any kind there. The logic just doesn't follow.

 

Interesting, magneto. I'll have a look at that.

 

Hello? What's this?

Arguing from authority.

And threats. No mention of prometheus's posts I see.

Along with the usual abuse.

 

I already know my posts are poor.

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My argument is based on scientific evidence. We're talking relativity here, it's reasonable to refer to Einstein to demonstrate that this isn't just something I'm making up.

The fundamentals is what we're talking about here. Things like what t really represents, the nature of spin, and the nature of matter. And you've previously said I do accept the wave nature of matter, as described by quantum field theory and quantum mechanics so please don't backpedal.

You can diffract single photons. And electrons. And neutrons. Go and look it up.

I beg to differ. A wave rotating in two orthogonal axes gives you the notion. Interestingly Thomas and Tait who coined the phrase spherical harmonics were into things like smoke rings. A smoke isn't an ideal analogy, but IMHO it gets you part way there.

No need to shout. We all know we aren't going to start measuring the speed of light different in one direction as opposed to another. That's what got the whole ball rolling with the Michelson-Morley experiment.

Space. But like I said, the lattice isn't actually there, it's just a visualization aid. It lets you visualize the displacement when a wave passes you by.

I said it's the way we're made of waves that underpins Lorentz symmetry, not the lattice.

OK. This has been an interesting discussion. I've certainly learned something, but I think we're going round in circles now, or backwards, and it's time to call it a day.

 

Yet I'm sure you would be among the first to argue that the age of an idea in itself is not an argument for accepting it. Pointing out that Einstein or Maxwell had what may have been a brain fart as far as you know does not mean we should take it seriously, and from what I've seen of you commenting on things famous past physicists said, I am not convinced you understand most of the quotations you produce in the way their original authors intended anyway.

But not all things are, and sometimes the way the brain naturally perceives things isn't the best point to start from.

When considering how you perceive space and time and motion, here's something to think about: the brain - the thing you're doing all this observing with - is a physical organ with a size on the order of about 10 cm and a lifetime of about 80 years on average. The characteristic time of a conscious decision or thought process is roughly in the range of about a tenth of a second to a second. I don't know how quickly neurons communicate, but if it's anything like the communication speed along nerves (I've heard hundreds of kilometres per hour), then the time it takes for information to get from one part of the brain to another is going to be smaller than the timescale of conscious thought, and your brain is just going to perceive itself to be working instantaneously. The same thing goes for the brain's perception of the world: in most practical scenarios, auditory and visual information propagates fast enough that it reaches you instantaneously as far as the brain is concerned. On the other hand, the brain's shelf life of several decades is many orders of magnitude longer than that characteristic time of thought processes of around a second or so, and the brain certainly doesn't perceive itself to be existing all at one moment. Not only that, but it has a highly asymmetric perception of time: it has a memory of past events but not of future events.

Given all that, I think it is pretty inevitable that the brain is naturally going to opt for the "all space, but not all time" view over any other possible view, and I think that makes it especially dangerous to try to argue that space and time are really different just because it looks that way. Mind what you're actually doing the observing with.

No it doesn't. Something having a magnetic moment only means that it has a magnetic moment. There is a difference between the raw facts that experiments actually show, and what the best explanation for the raw facts might be. The hypothesis that something is actually rotating in the electron may or may not be the best explanation for why it has a magnetic moment, depending on what else you know about electrons.

No, not necessarily. What you got off Wikipedia might have talked about the electron rotating "like a planet", but the same argument will apply just fine to whatever you might think is doing the rotating.

No it doesn't. There is no logical connection here.

Are you predicting that, three years from now, the mainstream perception of spin will have changed?

You are claiming that experimental results show things when logically they don't. Experiments don't actually literally show much more than the raw experimental results themselves. After that it's a matter to decide how best to explain those results with a theory or model, and that can change depending on exactly what you know.

Take one example that you keep bringing up, for instance: pair production. If you observe a process in which two photons go in and two electrons come out, then that is the fact that the experiment literally shows: there is a process in nature in which photons go in and electrons go out. You can't claim the experiment shows something about what happens in between, because you didn't actually observe that. In the experiment you only observed the initial situation and the end result.

Now, if that's all you know about electrons and photons, then I'll happily concede that the simplest explanation for this, that everyone would find the most natural, is that one particle is somehow made from the other or that they're both made from some common substance. But the isolated fact that you can trade photons for electrons isn't all we've observed about electrons and photons, or in general about light and matter. Based on many detailed investigations and observations in the areas of electromagnetism, optics, quantum physics in general and in particular atomic physics and quantum optics, collider experiments, and maybe others, the physics community has eventually come to the conclusion that the best way to model the electron and the photon, based on what we currently know, is with quantum electrodynamics. The problem here is, QED doesn't model the electron and the photon as being made of the same stuff - they're excitations of different fields with different properties - and if you know how QED is formulated in any detail it is pretty clear that QED can't trivially be modified to make electrons be made of photons. So the task falls on anyone wanting to claim that electrons are in any way made of photons to show that they can model the electron this way without breaking the experimental success of QED.

Same comment if you want to say something like this:

 

True.

Brain fart? That's a new way to diss and dismiss what guys like Maxwell and Einstein actually said. I understand those quotations pryzk, and the meaning is crystal clear.

I know. Hence my interest in things like The checkershadow illusion. This doesn't work for me any more. Honestly. I don't know if you've seen R Beau Lotto (http://www.lottolab.org/) on TV, but he said people who work professionally with colour learn how to avoid being fooled by context. With practice you get better at seeing what's there. Then when you apply this to physics, you realise that some of the things you took for granted aren't there.

All good stuff. Interesting thing, the brain. With my IT background I see it as a computer. I tke a cold hard view on all this, and I don't think people are quite as rational as they like to think.

It has a recordkeeping system, that's all. If X moves from A to B, the brain records its observations, and can play them back. It doesn't record observations it hasn't made. It doesn't observe or remember whether X moves from B to C or from B to D if X is moving between A and B. There's no symmetry involved apart from in your imagination.

It isn't inevitable at all. You can hold your hands up a yard apart, and see that there's a space between them. Then you can waggle your hands, and see motion. Can you see any time flowing? No. So where does your view come from? From your schooling. The schooling that leaves you utterly convinced that space and time are the same, so convinced that patent observational evidence counts for nothing. I can hop forward a metre, or back a metre. You can't hop forward a second, or back a second. Space and time are not the same. The evidence for that is patent. But you can't see it, and won't see it. You ignore that scientific evidence. That's dangerous.

There you go, ignoring scientific evidence again.

No it doesn't. Electrons don't go round protons like orbiting planets, and in similar vein a self-trapped 511KeV photon isn't moving faster than light. It just has a compound rotation.

Yes there is. You make an electron via pair production. Out of a photon that was moving linearly at c. Which now isn't there any more. But the electron is. It's got spin angular momentum, magnetic dipole moment, you can diffract it. And hey look, here comes the positron, pow, annihilation, photons again. Now where on earth did they come from? Make the connection pryzk.

Yes. We're already seeing a shift to "wavefunction is real". Quantum mysticism is being challenged, and I think it's going to be pretty interesting.

Sounds as if you're trying to make light of experiment, pryzk. I don't like the sound of that.

It demonstrates that you literally made matter out of light. And electron/positron annihilation tells you that you can reverse the process. Then low-energy proton-antiproton annihilation to gamma photons tells you that this is not unique to electrons and positrons, and that gamma photons are common to both annihilations.

It's a good tight theory in terms of accuracy and predictive power, but like Feynman said, it doesn't offer any intuitive understanding of what's actually happening.

I don't know the detail, but I know that QED talks of different fields. I think it's a shame.

It'll come, pryzk.

Noted.

 

Speaking of the brain or mind...

This is not true. It has been known since before recorded history that anything you tell yourself or even think, repeatedly becomes a component of experience and can even come to be remembered as having ocurred, as having been experienced.

It has been practiced as learning by wrote.., repitition, since before the written word. And continues to raise its head in psychology in the form of false memories.

Related psychological phenomena could take the implications even further, but serve no real constructive purpose here.

 

Duly noted, OnlyMe. I stand corrected. And it reminds me of the first principle is that you must not fool yourself - and you are the easiest person to fool. It's something I took to heart when I looked in the mirror five years ago.

 

My point is that you can't rely on the fact Maxwell or Einstein said something to deduce that it is correct or useful.

Funny, because you've often provided quotations that I find crystal clear when read in context, and yet I end up with a completely different idea of what they mean than you do.

There are two problems with this: 1) just because you can see around one illusion doesn't mean you can be sure you can see around all of them, and 2) you need an independent way of telling what's "really there" to know that you're seeing an illusion in the first place, and to certify that you've learned to see past the illusion.

Finally, this is too ironic for me to keep to myself: if you're so good at seeing what's "really there", how is it you keep misspelling my username? It's "przyk", and not "pryzk", that's really there in all the places the vBulletin software would put my username.

This is just a different way of saying what I already told you: it can record past observations but not future ones.

I didn't say there was. I was pointing out the distinct lack of symmetry.

You're doing exactly what I explained is very dangerous: making simplistic appeals to the way things look.

No, from a very broad understanding of the roles space and time play in physics.

What? Your evidence does not prove what you say it does.

What's a "compound rotation"?

That isn't new. The Everett interpretations of quantum physics considers quantum states to be real, physical things that really exist. It was formulated in the 1950s and became quite popular in the 70s. The Bohm interpretation also considers the wavefunction real and is even older, tracing its origins back to the late 1920s.

Quantum mysticism is something only pop science sources talk about.

Why are you bringing up these two points anyway? I don't have any issue with thinking of quantum states as being real, and I think it is perfectly possible to develop an intuitive understanding of quantum physics, though on its own terms rather than trying to shoehorn quantum physics into something it isn't. I wouldn't consider either of these points terribly controversial. But that doesn't mean I'll think just anything you say about quantum physics and things being made of waves is correct.

I'm pointing out that you can't go claiming an experiment shows things it doesn't. Magnetic moments don't imply rotation just because you say they do.

More correctly, it demonstrates that you can trade matter for light. It doesn't say anything about how that actually works.

Whatever you think of how intuitive or even complete QED is doesn't change my point: since QED is an excellent summary of basically all the observations we've ever made concerning light and matter, you can't ignore it. The fact that QED (and quantum physics in general) can't trivially incorporate the idea of electrons being made of photons is a very real issue.

And nobody should be going around claiming electrons are made of photons, as if it were fact, until it does come, assuming it ever does. That's how physics works: you have to be able to show that ideas actually work. And physics isn't a gambling establishment. You don't get prizes for voicing the right idea for the wrong reason.

 

Granted. Evidence matters.

Hence we talk. Would you like to talk about a particular example?

No problem. The main thing is that you appreciate that can't trust what you think. Once you're aware of that, you become more self-demanding. You say Why do I think this? and Is there any actual evidence to support my view?

Sorry. Nobody's perfect. That includes me.

Future observations aren't observations, and the brain doesn't record past observations. It records observations, then tells itself they're "in the past".

You said it has a highly asymmetric perception of time which suggested to me that you thought time was symmetric.

You still can't see any time flowing. It isn't dangerous to point out the observational evidence. But it is dangerous to ignore it and try to brush it off with words like simplistic.

I'm going to have to spit it out przyk: you don't understand time. That's the size of it. You have a deep-rooted conviction about it, and you lack the ability to examine your own view and ask yourself why you hold it, and why you reject any evidence that challenges it. This is a human trait, and it's far commoner than people think.

We'll just have to agree to differ on that.

It's where you have one rotation in a given plane and another rotation on an orthogonal plane. To get the idea walk round in circles with your arms out banking like an aeroplane.

Let's not get into the MWI. IMHO Bohm's pilot waves are better. The sort of think I'm trying to get across here is that you just stick to the pilot waves - the only thing that they're piloting are themselves.

The Copenhagen Interpretation is quantum mysticism. A lot of qualified physicists going round saying things like it isn't classical, the human brain can never hope to understand it. IMHO that's quantum mysticism too.

I brought them up because "intrinsic" spin isn't considered to be a real rotation, even though there's evidence that it is. You don't accept this evidence, but you haven't explained why.

How much more evidence do you need?

It does when you understand displacement current.

It certainly is. It's a hole in the heart of physics.

We've had rock-solid evidence that electrons can be made from light for decades. It's only a short step from there to treating the electron as a photon configuration. I find it pretty amazing that QED just doesn't cover pair production, that no electron model came out of it, and that QED was never extended to cover the proton.

No, it isn't a gambling establishment.

 

Let's be absolutely clear for the people lurking on this thread. Farsight does not understand QED in any meaningful way, and this quote proves it quite substantially. QED certainly "covers" pair production (in fact, a relativistic quantum field theory is the simplest possible way to get a theory where particle number is not conserved). The very famous calculation of the anomalous magnetic moment of the electron is performed by summing the quantum corrections to the fermion-boson vertex in QED (which is the diagram that, if you have time passing in a particular direction exactly corresponds to pair production.). The calculation of the magnetic moment of the electron agrees with the experimental value to one part in 10^9, which is the most accurate theory ever devised. In no way does QED predict electrons are made of photons and Farsight's assertion there is evidence for this is frankly crap.

Farsight: I'm starting to feel your contributions to this thread are trolling. There is absolutely no justification for the claim made in the quote above. Kindly stop it.

 

Let's be absolutely clear for the people lurking on this thread, pair production is evidence that electrons and positrons can be made from photons.

And I'm starting to feel that your knowledge of experimental physics is limited, and that to preserve your perceived expert status you will dishonestly censor evidence and discussion rather than act sincerely as a moderator.

 

The fact that you make this attribution indicates you have no idea what you are talking about. Photons and electrons are excitations of quantum fields which can interact. The excitations (particles) can be created or destroyed by these interactions. QED has been proven by experiment to be the correct theory of the electromagnetic interaction and shows without any ambiguity that photons and electrons are fundamentally different - you cannot change one into the other.

I make no claim to be an experimental physicist, but I certainly am well versed on particle physics. Citing misunderstandings about interactions of particles is not evidence at all, of course.

I have not taken any moderating action against you (yet) but if you have any complaints about the moderation on here, please feel free to contact another mod or admin about it.