One-electron universe
en.wikipedia.org
en.wikipedia.org
1. It's more akin to philosophy than to science: this suggestion either has no testable consequences (or if it does, its predictions look obviously false: see below).
2. In all of our observations of the universe there seem to be many more electrons than anti-electrons, but this concept would seem to imply that the number should be exactly equal. You can try to get around that, but anything you do is a stretch.[1]
3. The formalism of quantum field theory naturally includes plenty of situations where electrons and anti-electrons form "closed loops" in time. (The classic example is a something like a photon giving rise to a virtual e-/e+ pair that immediately annihilates back into a photon, but they can get a lot more complicated.) Those closed loops would not be connected to the hypothesized "one electron" bouncing back and forth through all of time, so this idea would fail to explain why they also look identical to the rest.
So in my book, the beauty of this idea lies entirely in the fact that it could be suggested at all. It doesn't actually match reality, but it does give some striking intuition about how particle physics works.
[1] You could suggest that there is some other (unobservably distant?) region of the universe where antimatter dominates, but there's absolutely no evidence to support that suggestion. As another idea, the quote in the link suggests that "maybe the extra anti-electrons are hiding in the protons or something". But anything of the sort would seem to eliminate the whole point of saying "it's all one electron" (which always has the same properties, etc.).
A Quantum Loooooop! https://www.youtube.com/watch?v=2rjbtsX7twc&t=1m23s
That would validate the modern day myths crafted by science fiction and comic book writers. Future generations will look back and ask, "How did they know?"
Exactly. I'm sure Feynman had a beautiful mind and we should rebel in his thoughts. However, let's not mistake that for science.
On a similar note, I had an idea where telescopes looking at very distant galaxies were just different states of the same galaxy - the milky way - as it evolved through time and through different space-time / gravity lenses.
... What? Feynman wasn't advocating this theory at all.
"But, Professor", I said, "there aren't as many positrons as electrons." "Well, maybe they are hidden in the protons or something", he said.
I would be shocked if there's a single thing Feynman has ever said in a scientific context that you could reasonably say, "Let's not mistake that for science."
i'm been wondering about validity of virtual particle trick - while it is preserves charge, etc... doesn't it violates entropy principle of the 2nd law, ie. a pair of e-/e+ seems to have less entropy than the original/resulting photon, thus e-/e+ always happy to produce a photon, while photon would never produce e-/e+ pair without "help".
(If there were just one produced by annihilation, you'd have great difficultly satisfying conservation of momentum and having that photon move at the speed of c (when looking in the center-of-mass frame).)
But as for your actual example, it's important to distinguish between virtual pair production and longer-lived pair production. A single photon can momentarily "decay" into an e-/e+ pair which then annihilates back into a photon, and in fact quantum field theory tells us that this sort of process is an intrinsic part of how photons travel through space. (Similar things happen for all other particles as well.) But conservation of energy and momentum during this process leads to weird effects like violations of the usual mass/energy/momentum relation of relativity, which is essentially why we call the e-/e+ "virtual" particles (or "off-shell"[1]).
For a "real" annihilation between an electron and a positron, you'll always wind up with two photons in the final state (necessary to conserve momentum and energy). By the same token, to produce an e-/e+ pair you'd need two photons, not just one, and those photons would need to have enough energy to provide the mass of both particles and enough kinetic energy to satisfy momentum conservation. I wouldn't invoke the 2nd law here (as I said above), but the point you're making is still valid: because so much of the e-/e+ energy is "used up" in their mass, there is less "phase space" available (fewer possible momentum states) in that configuration than as two photons, so the probability of winding up in that state is correspondingly lower. (Also, an electron and positron are electrically attracted to each other and will naturally tend to meet up to annihilate, but two photons have no such tendency.)
I'm not sure that any of that was interesting or useful, but there you go.
All the fundamental laws of physics, including the Schrodinger equation follow the 2nd law, so it is somewhat
>The glib answer here is that there's really no such thing as the 2nd law when you're talking about a small number of individual fundamental particles. The statement "entropy never decreases" is actually a purely statistical claim, and it only rises to its usual level of essentially unbreakable validity when you're dealing with macroscopic numbers of particles
All the fundamental laws of physics, including the Schrodinger equation, follow the 2nd law or in other words they describe application of 2nd law to the given area of physics, i.e. they express "entropy never decreases" principle in terms of the objects of that physical area.
>"there is less "phase space" available (fewer possible momentum states)"
ie. less entropy :)
>an electron and positron are electrically attracted to each other and will naturally tend to meet up to annihilate
2 particles having negative and positive charges - less entropy than the entropy of 2 resulting neutral particles. Attraction (getting closer - increasing entropy) and annihilation (erasing the charge difference - increasing entropy) are in full compliance with, and i'd say direct manifestation of, the 2nd law :)
The phase space argument means that it is less likely for the system to wind up in the e-/e+ state than in the 2-photon state, and calling that a manifestation of entropy is entirely sensible. But in general, there's a non-negligible chance that the system will wind up in the e-/e+ state anyway: it's very much a possibility (and becomes even more so when the total energy is greater).
I usually reserve the term "2nd law" for cases where the probabilities are tiny enough that it's essentially impossible for the entropy to decrease by any remotely significant amount. That level of certainty typically requires systems of many particles, not just one.
I understand that pure statistical interpretation allows for non-negligible chances of the violations. What i'm wondering about is whether strong, non-statistical, interpretation is valid - ie. whether anything looking like a violation is just a non-complete calculation. After all it is pretty fascinating that entropy principle applicable (at least in statistical interpretation) on all scales - from the whole Universe down to quantum systems and for all the physical laws/forces.
It's hard to list intuitive counterexamples to your suggestion here, since anything intuitive is by definition part of a macroscopic system that would obey the 2nd law anyway. But... for instance, are you saying that you don't believe in the Maxwell speed distribution in an ideal gas? If no molecular interaction could ever take a system from a larger to a smaller total phase space, then every molecule in an ideal gas should eventually converge to the RMS speed. That's a clear experimental prediction, and I'm pretty sure that the usual answer has been well-tested (both explicitly and implicitly).
What a scam.
I remember reading an article saying that in an electrical circuit it is not the electrons that are moving, but the energy. The electrons are just the medium.
http://en.wikipedia.org/wiki/Magnetic_monopole#Dirac.27s_qua...
Now combine this idea with the Heat Death of the Universe...
I say, I say, I say, can you find an anagram of BANACH-TARSKI?
Yes: BANACH-TARSKI BANACH-TARSKI.
(Mathematicians' sense of humour doesn't necessarily resemble anyone else's.)
http://en.wikipedia.org/wiki/Wikipedia:Getting_to_Philosophy
Not only did the monkeys produce nothing but five pages consisting largely of the letter S, the lead male began by bashing the keyboard with a stone, and the monkeys continued by urinating and defecating on it.
Nothing has made me wish for magnetic monopoles more.
The result is unexplained, and probably always will be. Subsequent searches have turned up nothing.
You only need one... :).
It is one thing to say that physical measurement of the first particle's momentum affects uncertainty in its own position, but to say that measuring the first particle's momentum affects the uncertainty in the position of the other is another thing altogether. Einstein, Podolsky and Rosen asked how can the second particle "know" to have precisely defined momentum but uncertain position? Since this implies that one particle is communicating with the other instantaneously across space, i.e. faster than light, this is the "paradox".[2]
The answer: It's the same electron being measured! No more paradox.
[1] http://en.wikipedia.org/wiki/EPR_paradox
[2] http://en.wikipedia.org/wiki/EPR_paradox#Einstein.27s_opposi...
Also the EPR paradox applies to quantum states that are not necessarily electrons.
FWIW the EPR paradox is no longer a paradox anyway since you cannot use entanglement to transmit information faster than the speed of light, therefore preserving locality. The reason Einstein et al. termed it a paradox was because they thought it represented some sort of instantaneous information transfer.
But, later experiments based on Bell's theorem seriously challenged the hidden parameter explanation, preserving quantum mechanics in the process.
So, that takes us back to instantaneous information transfer or a third option: one electron (or any particle for that matter)!
I propose that the electron when going 'backwards' across the reality projection/slicing plane are not actually travelling in time and producing 'negative' electrons with a positive charge, but are actually the 'electrons' we observe with opposite spin. This brings us back to a single electron on a twisted path with a single spin but giving us observations showing multiple electrons with 2 spins.
Paradox again resolved ;-)
(1) Ordinary "forwards" electrons exist in both spin states, and both states have negative charge, not positive charge. So the anti-electrons that we observe with positive charge can't be just ordinary electrons with their spins flipped.
(2) The spin reversal operator (also called the "parity operator") is unitary, but the time reversal operator, the one that changes a "forward" electron into a "backward" electron, is anti-unitary. So they can't possibly be the same operator.
Your statement (1) depends on the existence of multiple electrons, where the whole idea of this article idea is that only one electron exists, which is where my argument comes from.
(2) sounds like math and not something physical or 'real'. If this operator actually existed in reality such that a single electron's spin can be flipped by applying it to an actual physical electron? I'll answer that by saying, I doubt it, but I am not a particle physicist.
If this operator does exist, then one could not say that there was a single electron on a path, unless all electrons in the universe changed spin direction instantly after the application such an operator.
[1] Edit: changed 'plane' to 'surface'.
No, it doesn't. The single electron could still be acted on by various operators in the course of its twisty path through spacetime, which could make it appear in various different ways. Which operators might be acting is then deduced from the different ways electrons appear.
Your hypothesis amounts to the claim that the only operator that is required to act on the single electron, to explain all its different appearances, is the spin reversal operator. My point is that that hypothesis only accounts for the appearance of "electrons" (more precisely, different views of the single electron) with opposite spins and the same charge; it does not account for the appearance of "electrons" (different views of the single electron) with opposite charges, because no unitary operator can change the charge, and the spin reversal operator is unitary.
If this operator actually existed in reality such that a single electron's spin can be flipped by applying it to an actual physical electron?
Sure it does; there are many different kinds of experimental setups that can realize this operator. One of the simplest is an inhomogeneous magnetic field. The "operator" language is just a way of linking the math describing electrons with the physical setup that does things to them.
If this operator does exist, then one could not say that there was a single electron on a path, unless all electrons in the universe changed spin direction instantly after the application such an operator.
No, this is not correct. The operator can be localized, so it only operates on one "electron" (i.e., one particular segment on the single electron's entire worldline) at a time.
In fact, regardless of which operator acts on the electron, it has to be localized for the hypothesis that there is only one electron to make sense. The whole point of the hypothesis is that the single electron follows a highly twisted path through spacetime, so that it crosses any single spacelike slice of spacetime multiple times, with each crossing potentially having a different appearance (different spin, etc.). That means whatever operator acts on the electron to make its path through spacetime twist has to be localized--otherwise all the appearances of electrons everywhere in the universe at a given instant of time would be exactly the same, which they obviously aren't.
The image in my mind is the vibrating, twisty path /out there/, not necessarily in spacetime. Through this path passes a continuous surface that could be be thought of as the 'current moment' of our observable reality. Each crossing/intersection of the electron path through this surface would result in an observable electron. This would then result in the 'single electron' being be the intersection of a uniform diameter path along the reality surface.
But now that I've thought about it more it's starting to make less sense :) I was thinking these intesections would be pure, geometric points, but a google shows that electrons have a physical radius and I'm having a hard time coming up with any way that these intersection points would have a spin.
What would be the appearance of the electron in your model? I couldn't see it being what we would call an electron travelling along this spacetime path because it would have a need to be in multiple places at the same time; althought I'm sure the 'holographic universe' could somehow take this into account. Does your single electron have a form similar to what I described above?
Then you have a problem with the original suggestion by Wheeler/Feynman that the article in the OP describes, because that's what it describes.
The image in my mind is the vibrating, twisty path /out there/, not necessarily in spacetime.
"Out there" is spacetime. Spacetime is what the twisty path exists in.
Through this path passes a continuous surface that could be be thought of as the 'current moment' of our observable reality.
Each such "current moment" is a spacelike slice through spacetime.
Each crossing/intersection of the electron path through this surface would result in an observable electron.
More precisely, it would result in a single observation of "the" electron, since in this model there is only one electron--but it crosses the same spacelike surface multiple times, and each crossing results in a separate, distinct observation that, to the observers, looks like a separate electron.
This would then result in the 'single electron' being be the intersection of a uniform diameter path along the reality surface.
No, the "single electron" is the twisty path through spacetime--or, if you give it a nonzero spatial size, it's a twisty "tube" through spacetime. See below.
google shows that electrons have a physical radius
There are a lot of technicalities surrounding this, but it will do for this discussion.
I'm having a hard time coming up with any way that these intersection points would have a spin.
Actually, it's easier to see how an object with a finite radius could have a spin: just think of it as a spinning ball with that radius. (There are technicalities here too, but they don't really matter for this discussion.) If you think of the electron in its entirety as a twisty "tube" through spacetime, the electron's spin is just an extra twist to the tube: in addition to the tube itself bending, its surface twists like a barber pole. The intersection of this with a particular spacelike slice through spacetime would make the barber pole twist appear as a measured spin.
It's harder to see how a point with exactly zero radius could have a spin: how can a single point spin?
What would be the appearance of the electron in your model?
See above.
I couldn't see it being what we would call an electron travelling along this spacetime path because it would have a need to be in multiple places at the same time
Traveling along a spacetime path that bends is exactly what enables it to be in multiple places at the same time. Being in multiple places at the same time just means that the electron's world-tube through spacetime bends around so that it intersects the same spacelike slice multiple times, as above.
I'm also seeing a problem of names, where 'the electron' and 'the twisty path' are being used interchangeably, but we're also talking about 'an electron' and 'the electrons' that exist on the reality surface. It gets confusing :)
I can see the 'barber shop twist' as being able to provide the necessary spin, but I'm not seeing how a sperical radius can come about from a slice along a path; a circular diameter yes, but a spherical radius is escaping me, unless the slicing 'leaks' energy (or harmony) to create some filling space around the intersection.
Nice discussion, but the indentation level is getting deep. Continue over email? Mine is in my profile if you're interested.
This depends on how "spacetime" is defined, which, as far as I can tell, depends on who is doing the defining. I've seen some papers where the word "spacetime" is applied to the full 10- or 11-dimensional manifold on which string theory (more precisely, superstring theory) is done; I've seen others which carefully use "spacetime" only to apply to the 3+1 manifold we actually observe, and use other terms like "internal symmetries" to describe the other dimensions.
That said, I think there is a more fundamental issue with a model which says there is only one electron and it moves in a twisty path through all 10 or 11 dimensions instead of just 4. (I see you actually had in mind a model with the twisty path not including the time dimension; that won't work either, see below.) Such a model could be constructed, but in order to compare it with experiment, it would have to make predictions involving only the 4 dimensions (3 space + 1 time) that we actually observe. In other words, whatever is happening in the other dimensions would have to boil down to determining the numbers or coefficients that appear in the ordinary 3+1 dimensions, things like the mass and charge of the electron; we have no way to actually observe "movement" in the other dimensions, and we certainly do observe electrons moving in the 3+1 dimensions, so the only predictions we can test are predictions about movement in the 3+1 dimensions, and other things like the mass and charge of the electron that we can measure in 3+1 dimensions.
In other words: any model that says "there is only one electron" has to include that one electron following a twisty path in the 3+1 dimensions we observe, regardless of what it says about the electron's path in other dimensions. And whatever it says about the electron's path in other dimensions can't be tested experimentally anyway, except if it makes predictions about numbers like the mass and charge of the electron that we can measure.
My argument is based on the twisty path moving through n dimensions (including the first 3) and not necessarily through the +1 of time.
Time has to be included, because we observe electrons at different times. A twisty path that didn't move through the time dimension would predict that we would only observe electrons at one single instant, and then they would all vanish (because the single electron underlying all those observations doesn't move through the time dimension).
I'm not seeing how a sperical radius can come about from a slice along a path
Remember that the "slice" is 3-dimensional. When you are imagining a circular slice, you're imagining a 2-dimensional slice. The 3-dimensional analogue of that is a spherical slice; in other words, the intersection of a 3-dimensional slice out of spacetime with the twisty tube that is the electron is a sphere.
Also, string theory even today is speculative; a lot of physicists think it's a good theory, but it is experimentally untested, because nobody can think of a way to test it; we can run plenty of experiments that are consistent with string theory, but they're also consistent with lots of other theories. We don't know how to run experiments that will help us to distinguish between string theory and the others.
And in any case, the point of the model is to describe observations of electrons that we can make directly; those observations don't involve extra dimensions even if there are any. They directly involve the four dimensions we can directly observe, three spatial dimensions plus time, i.e., spacetime. Even if there were string theory machinery "behind the scenes", so to speak, it would still have to be describable at some level as electrons moving through spacetime.
It's a measurement artifact, based on our presumption that there is more than one electron.
That is, measurement itself is simply a way to quantify what we perceive and understand. So, our perception that we are measuring more than one particle is the same lens through which that measurement is produced.
Or, garbage in, garbage out.
Instead, let's assume that there is one electron. Then, we would have to derive different metrics for explaining what we observe (spin, locale, charge, etc.). How does that electron appear to be in multiple places simultaneously? Why does it appear to possess multiple properties?
What mechanism do we have to explain that? And what is missing in our understanding or ability to perceive that makes us believe it's impossible? Is there another dimension? Or is it truly a function of time that we don't understand?
That would mean you are colliding the sole electron with itself?
What about electrons on the opposite sides of a planet or even universe, they are violating the speed of light without any gain in mass if it's a single entity.
How about when an electron falls into a blackhole, why aren't all the other "copies" affected by the dramatic space-time shift of such an event?
Unless we are dealing with an infinite-outcomes model where there are no paradoxes.
Other times they are often nothing more than artificial (relative to fundamental reality) products of mathematical complexities, edges, holes, paradoxes, and artifacts... Artifacts that shouldn't seriously be used-on or applied-to anything outside of whatever mathematical framework created them - but often are.
I don't remember the source but once I've heard a hypothesis that God is an electron with intelligence. It could be the same electron Feynman was talking about :)
Imagine you create two entangled particles, A and B. They have a number of properties, like momentum, position, and spin. Let's use spin for this example. You don't know these values yet, since they've never been measured—they could have clockwise or counterclockwise spin. However, you know the particles have opposite values. One is clockwise and the other must be counterclockwise. You then allow them to travel really far from each other, and you measure the spin of particle A—let's say it's clockwise. Because of that, you now know that particle B must have counterclockwise spin. You just learned something about a distant particle instantaneously. However, the data didn't really travel anywhere. If you interact with particle A, and change its spin to counterclockwise, particle B won't be affected. So you can't manipulate one particle to have effects on the other instantaneously (or faster than the speed of light).
This explanation seems pretty intuitive to me, but correct me if it's wrong.
EDIT: It almost seems stupid that there would be a whole theory based around this, since one would think we can just say particle A was clockwise and particle B was counterclockwise the whole time, but there is an important distinction to be made. We can't just assume they were in a certain state before we measured them. The whole premise of quantum superposition is that before being measured, the particles are a "superposition" of both states—for all we know they could both be either clockwise or counterclockwise. Just because we then measure them and determine what they are doesn't mean they had a single state before they were measured—that's an assumption. Removing the assumption creates so many consequences that we now have a whole subfield of science dedicated to understanding this stuff.
So back to the particles, if they're in both states before one of them is measured, and now they both have to resolve to one state, in some sense there is something traveling between them, letting the other one know what it has to be.
http://www.amazon.com/Stalking-Wild-Pendulum-Mechanics-Consc...
>"Feynman's thesis advisor, John Wheeler, proposed the hypothesis in a telephone call to Feynman in the spring of 1940"
Search google for "bashar prime radiant"
The idea is that since positrons can be viewed as electrons moving backwards in time, it may be the same electron weaving its way to the future and past countless times. But that would imply that the number of electrons in the universe = the number of positrons.
Hence Feynman's objection.
Unlike many similar theories though, the people behind this have enough scientific credentials to make it maybe plausible?
So why is the article so short? Has there been any additional research?
It's an interesting hypothesis, but without a testable and falsifiable theory, it's not really something we can study.
This is just one of the many things that fell out of feynman's brain when he wasn't concentrating. AFAICT he produced ideas like this the same way the rest of us produce farts.
Imagine if someone or something were to destroy this electron?
Imagine, if we had split the electron instead and then BAM, no more space and time.
There's a variety of interesting theory-things which treat a particle's absorption as an emission back in time, as well; the difference is that here is the "same particle" tracing all those lines, instead of just one of those lines.