Are electrons real?

[Resha Caner]

I came across an intriguing quote from Betrand Russell written in the mid 1930's.

 

"An atom is now merely a convenient way of grouping certain occurences; it is convenient, up to a point, to think of the atom as a nucleus with attendant electrons, but the electrons at one time cannot be identified with those at another, and in any case no modern physicist thinks of them as 'real.'"

 

Is this truly the current view of an electron? I ask because I have wondered for some time if the constants associated with electrons (electric charge of −1.602E−19 C, mass of 9.11E−31 kg) are "fixed".

 

In other words, are these "universal constants" associated with some theory, are they approximate values of a physical reality, a concept that is completely out of date, or something else?

 

Until coming across Russell's statement, I had thought of electrons as real, and wondered to what accuracy their properties had been measured, and if it was possible for those properties to vary to some extent.

 

Any help would be appreciated.

 

Caner

[Graviphoton]

An electron is real, but we cannot make any considerations on their positions in an atom, or otherwise, because it is useless.

 

Bertrands arguement, was why the one-electron universe theory was proposed.

[Resha Caner]

Thanks for the reply.

 

I know of the uncertainty in observing any specific electron. And I assume we're saying the one electron universe has been disproved.

 

That takes me back to my original question, then. Are the properties of an electron fixed? In other words, is every electron EXACTLY the same as another in mass and charge?

[Graviphoton]

Yes. Each electron, as far as we can mathematically tell, have identical properties. We don't even know if the electron has a structure we can talk about. Its radius is infinitesimal next to being able to be measured. All attempts to measure its radius have failed, so we make educated guesses.

[John Cuthber]

If an elecron isn't real what leaves the tracks in a cloud chamber with a beta source in it?

[swansont]

Define "real." Physics is concerned with describing the behavior of nature, not the essence of nature.

 

There is some phenomenon that manifests itself as a point charge with those values in the models we have for how nature behaves. (really successful models, too)

 

Are electron holes real? Are phonons? Photons? Or are they manifestations of some model? (current flow in semiconductors, physical vibration modes and electromagnetic vibration modes, respectively). Personally, I'd say no, no and yes, but then, I do atomic physics. I'd imagine a solid-state physicist would make a case for the others being real.

[Graviphoton]

I would say yes, depending on the state of the particle. If it is virtual, or in any wave state, then no, because then physics defines it as ethereal and non-existant. Thus Copenhagen states that when you observe the particle, whether it be a human observer or not, it can ''pop'' the particle into existence.

[Resha Caner]

Define "real." Physics is concerned with describing the behavior of nature' date=' not the essence of nature.

 

There is some phenomenon that manifests itself as a point charge with those values in the models we have for how nature behaves. (really successful models, too)

 

Are electron holes real? Are phonons? Photons? Or are they manifestations of some model? (current flow in semiconductors, physical vibration modes and electromagnetic vibration modes, respectively). Personally, I'd say no, no and yes, but then, I do atomic physics. I'd imagine a solid-state physicist would make a case for the others being real.[/quote']

 

I'm not trying to be philosophical. I meant "real" in exactly the way you say it. Is the electron, at this point, considered an irreducible phenomenon, or is it the manifestation of other, more fundamental phenomena.

 

Yes. Each electron, as far as we can mathematically tell, have identical properties.

 

Thanks again. And I'm sorry if I'm appearing a bit anal retentive about this, but I find the idea that each electron is identical fascinating. For some odd reason, my intuition says each would be unique. So, I need to dig at your reply a little bit. You say we know this "mathematically".

 

Does that mean: 1) we measure the properties of an electron directly, or do we 2) deduce their properties from other phenomena ... or do we 3) deduce them from theory?

 

If we measure the properties directly, to how many significant digits have they been measured? Do people strive to measure them more accurately?

 

I guess I am asking if electrons can be "proven" to be identical, or do we merely assume so because we can't measure them any more accurately than we have?

 

Would it shake any theories if it turned out they weren't identical?

[Graviphoton]

Well, we know they are identical, because if we take one electron, try and measure its structure, we find it doesn't really have a structure at all. For this reason, all electrons do not have structures, and are therefore identical in this sense.

 

Of course, as it goes, we do observe an electron, despite it having an infinitesimal non-structure. If it has a radius that can be measured directly, then we don't have the technology yet to make an accurate reading (last i heard).

 

But no, i shouldn't imagine it would shake our theories, but in fact make them easier to contemplate, because then, scientists wouldn't be forced to resort for explanations how there is such an intrical design, such as the one-electron universe theory i told you about. Hope this helps.

[swansont]

 

Does that mean: 1) we measure the properties of an electron directly, or do we 2) deduce their properties from other phenomena ... or do we 3) deduce them from theory?

 

 

If we measure the properties directly, to how many significant digits have they been measured? Do people strive to measure them more accurately?

 

http://en.wikipedia.org/wiki/Electron

 

gives charge, mass and magnetic moment. People do try and devise better experiments for these.

 

I guess I am asking if electrons can be "proven" to be identical, or do we merely assume so because we can't measure them any more accurately than we have?

 

Would it shake any theories if it turned out they weren't identical?

 

If they weren't identical that would have ramifications. It's part of the theory, and nuclear and atomic interactions would vary if they weren't. i.e. outcomes of chemistry couldn't be predicted — chemistry just wouldn't work. The Pauli principle wouldn't hold if the particles weren't identical.

[Resha Caner]

Yes, we're inching toward what I'm looking for. But I still don't feel I have a solid answer. Maybe there isn't one.

 

Don't be afraid to direct me elsewhere. For example, if there's a book I need to read because of an obvious hole in my background, that's my responsibility. I'm not asking you to teach me physics.

 

On the other hand, if you don't mind continuing the conversation, and slogging through this with me, I greatly appreciate you helping me to understand.

 

So, let me ask this in a different way. I open up my college physics book, and it tells me an electron has a charge of 1.602176487 E-19 C. Further, it tells me this is a fundamental physical constant. If I found an electron with a charge of 1.6021764871 E-19 C or 1.6021764869 E-19 C, then I should assume my measurement was in error, not that the fundamental constant was imprecise.

 

So my question, then, is how do we know this is the exact fundamental charge?

 

If they weren't identical that would have ramifications. It's part of the theory, and nuclear and atomic interactions would vary if they weren't. i.e. outcomes of chemistry couldn't be predicted — chemistry just wouldn't work. The Pauli principle wouldn't hold if the particles weren't identical.

 

I didn't see this before I made my post. I do have a physics book with the constants in them, and I've browsed through Wiki - but that doesn't mean it's accurate.

 

In any case, I think you just answered my question. Thanks.

 

In fact, your hint led me to this article in wiki (now we'll just hope it's accurate).

 

http://en.wikipedia.org/wiki/Identical_particles

 

Thanks, Caner.

[D H]

So, let me ask this in a different way. I open up my college physics book, and it tells me an electron has a charge of 1.602176487 E-19 C. Further, it tells me this is a fundamental physical constant. If I found an electron with a charge of 1.6021764871 E-19 C or 1.6021764869 E-19 C, then I should assume my measurement was in error, not that the fundamental constant was imprecise.

What makes you think that? There are several physical constants whose values are measured, the electron charge being one of them. All measurements have errors associated with them, resulting in an uncertainty in the estimated value. The uncertainty in the electron charge is about 2 parts in 10^-8, so your stated values are well within that uncertainty.

 

Some physical constants, such as the second and speed of light, do have zero uncertainty, but that is because we have defined the constant to have that particular value.

[Resha Caner]

My statement was more a hypothetical one than something I firmly believe in. In fact, I believe the opposite, but didn't have enough confidence in my knowledge of physics to state it.

 

You guys have helped a lot, and I greatly appreciate that. Thanks.

[hobz]

Does anybody know a working definition of real?

Is "real" that which can be measured?

Is a thought real? Is a dream real? Is an electromagnetic field real? Are abstractions real?

[Mr Skeptic]

In one sense, each electron is identical -- same mass, charge, magnetic moment. In another, each electron is unique, as required by the Pauli Exclusion Principle. No surprise there, if you can tell the difference between two electrons then they need to have some properties different, such as different positions.

[Icemelt]

Well, we know they are identical, because if we take one electron, try and measure its structure, we find it doesn't really have a structure at all. For this reason, all electrons do not have structures, and are therefore identical in this sense.

 

Come on !

We discover something we can't properly measure, so by definition it must be identical to all other similar objects we can't measure !

This is one of the least acceptable arguments I've ever heard

 

How about:

"We are unable to measure the structure of an electron because it is continually changing its state. Therefore in this respect each electron is unique since its state can never be synchronized with another"

 

To me this seems a much more plausible conclusion !

[Klaynos]

There is a difference between us not being able to measure something and it being physically impossible for it to be measured.

[elas]

'The enigmatic electron' by McGregor deals extensively with the various ways of measuring electron radius.

'Composite fermions' by Jain shows what can be done by distorting the shape.

 

'The ideas of particle physics' by Coughlan, Dodd and Gripaios. and 'Facts and mysteries in Elementary particle physics' by Veltman give a clear explanation of current knowledge.

 

I do not think Bertrand Russell would make the same statement today.

[swansont]

The electron is not a composite fermion.

[Radical Edward]

electrons obey the Pauli Exclusion principle, which states that no two identical fermions can occupy the same atomic levels. Electrons obey this, and fall into the fermi distribution, so they are identical.

[swansont]

Fractional Quantum Hall Effect discussion moved. http://www.scienceforums.net/forum/showthread.php?t=33509

[Resha Caner]

'The enigmatic electron' by McGregor deals extensively with the various ways of measuring electron radius.

'Composite fermions' by Jain shows what can be done by distorting the shape.

 

'The ideas of particle physics' by Coughlan, Dodd and Gripaios. and 'Facts and mysteries in Elementary particle physics' by Veltman give a clear explanation of current knowledge.

 

I do not think Bertrand Russell would make the same statement today.

 

I'll look up your references ... and hopefully I'll be able to understand them.

 

But maybe it would be fun to do this from a different angle with a little thought experiment.

 

Let's suppose two electrons are different. Say we are studying hydrogen gas that is pure protium (one proton, one electon, and no neutrons per atom). Within the gas, the charge of the different electrons varies. What would we expect to see that is different from a protium gas where all the electrons have the exact same charge? Is anything different?

[elas]

 

Let's suppose two electrons are different. Say we are studying hydrogen gas that is pure protium (one proton, one electon, and no neutrons per atom). Within the gas, the charge of the different electrons varies. What would we expect to see that is different from a protium gas where all the electrons have the exact same charge? Is anything different?

 

Jain states that the electrons in composite fermions can have different energies, but he does not mention different charge values. Tsui et al deal with fractional charge but do not do so in reference to electrons although, of course, the experiments uses electrons compressed in a magnetic flux.

[swansont]

Let's suppose two electrons are different. Say we are studying hydrogen gas that is pure protium (one proton, one electon, and no neutrons per atom). Within the gas, the charge of the different electrons varies. What would we expect to see that is different from a protium gas where all the electrons have the exact same charge? Is anything different?

 

You'd have a different spectrum, for starters, because the energy levels depend on the strength of the interaction. It's also possible that the bonds would be affected, where you might be able to form H₃, for example.

[Resha Caner]

You'd have a different spectrum, for starters, because the energy levels depend on the strength of the interaction. It's also possible that the bonds would be affected, where you might be able to form H₃, for example.

 

Cool. I guess I'm wondering, though, whether there is some type of "averaging" effect such that the differences wouldn't be noticable. I wouldn't expect that all the electrons would skew in the same direction, but that the variations in charge would be randomly distributed. So, isn't it more likely that there would simply be some scatter in the spectrum? Which might be dismissed as measurement error.

 

Or am I missing something about what you said?

 

How about this. Instead of using Protium, maybe we would need to oxidize the hydrogen to strip off the electon (I think that works). I don't know if you have to create some kind of ionic compound to keep it stable (or maybe even go the other way and make a hydride).

 

But, once charged, then maybe you could separate the heavier charges from the lighter charges by flowing the gas between charged plates. Once that's done, then you'd be able to see a definite shift in the spectrum between the separate gases.

 

Is that a plausible experiment? Or, do I need to take this to the chemistry forum?

 

Caner