Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: socratus on 16/08/2006 13:39:28
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Very simple question:
What is the specific formula of the electron ( not a symbol)?
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Commentaries:
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1.
e-
2.
electrons donot have formulas
but have charge which is expressed by e and
unit is coulombs. e=1.6*10^-19.
or for mass comparing with proton
(mass of electron=(1/1836) *mass of proton).
3.
The formula for what? the speed? the densiity?
Be more specific.
If you just mean the symbol it is (e-)
4.
(A very stupid question indeed!)
What does one really mean by the formula for an electron?
If u mean symbol, then the answer could be e-
5.
Time-independent Schrodinger wave equation
in one dimension for an electron is:
d^2 Ô/ dx^2 = - (2m/h^2)[E - U(x)] Ô(x)
6.
Not simple, you are actually right,
expecting even an electron to have a formula.
But the very behaviour of a simple electron can
constitute a formula occupying miles in paperwork.
If one day we work out that formula,
even to some approximation,
then a true window called science has opened to us.
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Please, your opinion.
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Some other commentaries:
1.
Electron does not have formula, it has only notation as e-.
2.
electron is a particle
how can a particle have an equation ?
wrong question, sorry
if u r asking about representation then it is "e"
3.
You can find a formula for the one or other aspect of an electron,
but not for all of them at the same time.
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My answer is:
Electron has own formula.
1.
Physical parameters of an electron (mass, charge)
were discovered as a result of experiments.
2.
Einstein, Bohr wrote down energy of an electron
(in interaction with atom) by the formula:
E=hw.
3.
In 1928 Dirack formulated the equation of an electron,
(relativistic equation of the electron) in such way:
E = (plus, minus)mc^2
4.
Why does nobody analyze interrelation between
energy of Einstein/ Bohr,s electron (E=hw) and
energy of Dirack,s electron (E = (plus, minus)mc^2)
It means, that one electron has three (3) formulas of
energy.
It means that an electron is really a very complex
particle and according to Hertz it is possible to say, that
the formulas of an electron are cleverer than the man.
If somebody will try to explain why electron has three (3) formulas,
please, recollect that an electron is not a firm figure.
Electron can change its own form depending on its speed.
It means, that energy and form (together) of an electron
depend from some kind of movement. And it is impossible
that electron can change its form, its energy but its charge
will remain constant.
Electron can also change its charge.
This changes of an electron depend on its impulse.
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5.
In 1916 Sommerfeld discovered the formula of an electron.
The formula of electron is:
(e^2=hca).
But nowhere, in no textbook
the formula of electron is not written down in this way.
Why?
Nobody can understand what sense of constants
in the Sommerfeld.s formula of electron is.
==================
The formula of Sommerfeld,s electron consists
from three constants:
1.
h=h/2pi (impulse of Goudsmit-Uhlenbeck)
2.
c (speed of quantum of light)
3.
a ( coefficient of constant thin structure.)
The existence of this extremely important fundamental dimensionless
constant remained unexplained till now.
And this quantity determines a condition of an electron
It means, that diverse physical and chemical properties of substances
In many respects are determined by this quantity.
This constant remained unknown in modern physics and
on Feynman,s expression , which he said with humour
that this quantity is
" by the god given damnation to all physicists ".
=============
We know how whole Universe was created from
the first second ( from big bang , of course).
But on simple question :
“ What is an electron?”,
“ What is a formula of an electron?”
we don’t have answer.
=======================
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Talk to Feynmann and friends they developed Quantum Electro-dynamics, which I think combined QM and electromagnetism (and therefore by definition relativity)
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surely it is meaningless to talk of the density of an electon, electrons are point objects of zero dimensions hence infinite density
syhprum
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quote:
Originally posted by syhprum
surely it is meaningless to talk of the density of an electon, electrons are point objects …
correct
quote:
…of zero dimensions hence infinite density
syhprum
hmm, perhaps not. but it is certainly very point-like in behaviour and has a finite mass.
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quote:
Originally posted by syhprum
surely it is meaningless to talk of the density of an electon, electrons are point objects of zero dimensions hence infinite density
...and infinite electric potential energy! You understand well that this is impossible!
This problem has engaged physicists for almost a century and it's not solved yet!
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Electrons are at first sight simple but are stranger than what you might think, apart from the infinities that crop up there is another argument as to why they cannot be of zero dimensions. We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Is it possible that an electron has a very small dimension say meter*10-35 (planck limit?) which is unobservable (al la string theory)
When they are moving they have a well defined wavelength rather like photons but with rest mass
syhprum
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quote:
Originally posted by syhprum
We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Electrons have a quantum "property" called Spin, but they don't rotate around themselves. I wrote "property" because, if you assume it's well defined, it turns out it's an "hidden variable", and Bell's inequality and experiments have shown hidden variables don't exist.
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Formula of an electron? I don't really understand this question.
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quote:
Originally posted by lightarrow
quote:
Originally posted by syhprum
We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Electrons have a quantum "property" called Spin, but they don't rotate around themselves. I wrote "property" because, if you assume it's well defined, it turns out it's an "hidden variable", and Bell's inequality and experiments have shown hidden variables don't exist.
bell's theorem says that spin does not exist? i'm sorry, i think i misunderstood.
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quote:
Originally posted by bostjan
quote:
Originally posted by lightarrow
quote:
Originally posted by syhprum
We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Electrons have a quantum "property" called Spin, but they don't rotate around themselves. I wrote "property" because, if you assume it's well defined, it turns out it's an "hidden variable", and Bell's inequality and experiments have shown hidden variables don't exist.
bell's theorem says that spin does not exist? i'm sorry, i think i misunderstood.
I haven't said spin doesn't exist, but that is a strange "property". I explain.
Stern-Gerlach: you have (silver) atoms passing a magnetic field with vertical gradient and then half of them go up and half go down. "Explanation": they have a magnetic momentum, like a little compass needle, wich we'll call "Spin" and wich can have any direction in space; the magnetic field gradient acts on it and, on average, half of them go up and half down.
Now I ask you a very simple question: Can you say that, after interacting with the magnetic field, those atoms (or whatever they are) going up, does have a "spin up" property?
In case you answer "yes", consider the following:
You make these "spin up" atoms pass into an horizontal gradient magnetic field. Half of them go left and half right. Ok! nothing strange.
Now you make them (the left ones or the right ones or both, it doesn't matter) pass again through a vertical gradient magnetic field.
What happens? They all were "spin up" atoms, isnt't it? So, of course they all should have to go up!
Probably you already know that this doesn't happen: half of them go up and half go down!
Is this a real property of an object?
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It is quite easy to understand the magnetic field of atoms, an atom consists of a nucleous with a cloud of electrons rotatinting around it, the extreme case is the hydorgen atom with only one electron which makes atomic hydrogen very energetic so that it is normaly only found in molecular form.
Is there a magnetic field associated with an isolated electron when it is stationary (or nearly)
syhprum
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Electrons are never stationary. like all matter particles they are dynamic structures they just get "bigger" as they move slower. That is the matter waves associated with the particle become longer.
Dirac described the electron in quantum mechanical terms to incredible precision with his equations of electrons but that does not explain their mass or spin.
I have already described electromagnetic waves (or photons)in terms of a contiuous interplay between electric and magnetic fields. Particles with mass are best thought of in the same way as persistent dynamic structures in space time like four dimensional solitons. The shapes continually change but the detailed structure defines the particle. There are some suggestions as to what this stucture might be coming out of "loop quantum gravity theory" it is also envisaged that charged particles have twists in their structure.
Now if you consider a dynamic twisting structure of space time continually changing between the set of possible shapes that defines its identity it is quite possible to understand why such a particle should ontain angular and magnetic momenum in the form of "spin"
If we learn anything from our observations of the universe we learn that it is not a static place and any theory that contains point particles and static singularities is very likely to be wrong.
Learn, create, test and tell
evolution rules in all things
God says so!
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This is probably the place to clarify one of the questions that I have often heard about atomic structure. That is why don't the electrons collapse on to the nucleus but move in orbits. Now its clear that the S1 and above electrons have angular momentum and are kept away from the nucleus ny the two S0 electrons with opposing spins but what about the S0 ones that have no net angular momentum. The answer is that they HAVE collapsed on to the nucleus but the low mass and energy content of the electron means that they are quite big physically and it is much more likely that they will be found outside the nucleus than inside it!
Learn, create, test and tell
evolution rules in all things
God says so!
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i still don't understand the correlation between bell's theorem and spin.
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quote:
Originally posted by bostjan
i still don't understand the correlation between bell's theorem and spin.
http://atschool.eduweb.co.uk/rmext04/92andwed/pf_quant.html#Q30
Here it was described an experiment made with photons, but could be made with electrons, protons ecc. as well.
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I grew up in an age before neutrons when atomic nuclei contained electrons and protons, atoms had nuclei with little solid electrons whizzing around them and we had a nice solid ether for electo-magnetic waves to propagate in.
I sometimes long for the old days and find modern physics rather puzzling (I am not as old as Methusala but our school textbooks were)
syhprum
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the epr paradox has to do with measuring two correlated spins simultaneously. i don't think bell's theorem contradicts the existance of spin all together.
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quote:
Originally posted by bostjan
the epr paradox has to do with measuring two correlated spins simultaneously. i don't think bell's theorem contradicts the existance of spin all together.
Please, explain the result of Stern-Gerlach experiment I have showed you in my post, in terms of spin as a real property of an atom or electron or else.
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Just read the paper you posted, Bell's original paper, and the EPR paradox.
The Stern-Gerlach experiment shows that spin is real and observable A Stern-Gerlach device only measures the z component of spin (where z is along the axis of the beam. If the spin is one half, the beam splits into two parts, one with the z-component of spin positive and the other negative.
Bell's theorem deals with hidden variables (the hidden variable being the correlation between the spin states of two separate particles heading in opposite direction). Bell showed that these hidden variables are illogical (those variables that relate the two spin states). The reason Stern-Gerlach is mentioned is because it is the apparatus used to measure spin.
Quantum spin states are very real. See Scientific American 241, 158 (Nov. 1979) by B d'Espagnat.
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quote:
Originally posted by lightarrow
quote:
Originally posted by syhprum
We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Electrons have a quantum "property" called Spin, but they don't rotate around themselves. I wrote "property" because, if you assume it's well defined, it turns out it's an "hidden variable", and Bell's inequality and experiments have shown hidden variables don't exist.
bell's theorem says that spin does not exist? i'm sorry, i think i misunderstood.
-
quote:
Originally posted by bostjan
quote:
Originally posted by lightarrow
quote:
Originally posted by syhprum
We are told that they spin, now when I observe something spinning the front side is moving in one direction and the backside in the other, if there is no distance between front and back there can be no spin.
Electrons have a quantum "property" called Spin, but they don't rotate around themselves. I wrote "property" because, if you assume it's well defined, it turns out it's an "hidden variable", and Bell's inequality and experiments have shown hidden variables don't exist.
bell's theorem says that spin does not exist? i'm sorry, i think i misunderstood.
I haven't said spin doesn't exist, but that is a strange "property". I explain.
Stern-Gerlach: you have (silver) atoms passing a magnetic field with vertical gradient and then half of them go up and half go down. "Explanation": they have a magnetic momentum, like a little compass needle, wich we'll call "Spin" and wich can have any direction in space; the magnetic field gradient acts on it and, on average, half of them go up and half down.
Now I ask you a very simple question: Can you say that, after interacting with the magnetic field, those atoms (or whatever they are) going up, does have a "spin up" property?
In case you answer "yes", consider the following:
You make these "spin up" atoms pass into an horizontal gradient magnetic field. Half of them go left and half right. Ok! nothing strange.
Now you make them (the left ones or the right ones or both, it doesn't matter) pass again through a vertical gradient magnetic field.
What happens? They all were "spin up" atoms, isnt't it? So, of course they all should have to go up!
Probably you already know that this doesn't happen: half of them go up and half go down!
Is this a real property of an object?
-
It is quite easy to understand the magnetic field of atoms, an atom consists of a nucleous with a cloud of electrons rotatinting around it, the extreme case is the hydorgen atom with only one electron which makes atomic hydrogen very energetic so that it is normaly only found in molecular form.
Is there a magnetic field associated with an isolated electron when it is stationary (or nearly)
syhprum
-
Electrons are never stationary. like all matter particles they are dynamic structures they just get "bigger" as they move slower. That is the matter waves associated with the particle become longer.
Dirac described the electron in quantum mechanical terms to incredible precision with his equations of electrons but that does not explain their mass or spin.
I have already described electromagnetic waves (or photons)in terms of a contiuous interplay between electric and magnetic fields. Particles with mass are best thought of in the same way as persistent dynamic structures in space time like four dimensional solitons. The shapes continually change but the detailed structure defines the particle. There are some suggestions as to what this stucture might be coming out of "loop quantum gravity theory" it is also envisaged that charged particles have twists in their structure.
Now if you consider a dynamic twisting structure of space time continually changing between the set of possible shapes that defines its identity it is quite possible to understand why such a particle should ontain angular and magnetic momenum in the form of "spin"
If we learn anything from our observations of the universe we learn that it is not a static place and any theory that contains point particles and static singularities is very likely to be wrong.
Learn, create, test and tell
evolution rules in all things
God says so!
-
This is probably the place to clarify one of the questions that I have often heard about atomic structure. That is why don't the electrons collapse on to the nucleus but move in orbits. Now its clear that the S1 and above electrons have angular momentum and are kept away from the nucleus ny the two S0 electrons with opposing spins but what about the S0 ones that have no net angular momentum. The answer is that they HAVE collapsed on to the nucleus but the low mass and energy content of the electron means that they are quite big physically and it is much more likely that they will be found outside the nucleus than inside it!
Learn, create, test and tell
evolution rules in all things
God says so!
-
i still don't understand the correlation between bell's theorem and spin.
-
quote:
Originally posted by bostjan
i still don't understand the correlation between bell's theorem and spin.
http://atschool.eduweb.co.uk/rmext04/92andwed/pf_quant.html#Q30
Here it was described an experiment made with photons, but could be made with electrons, protons ecc. as well.
-
I grew up in an age before neutrons when atomic nuclei contained electrons and protons, atoms had nuclei with little solid electrons whizzing around them and we had a nice solid ether for electo-magnetic waves to propagate in.
I sometimes long for the old days and find modern physics rather puzzling (I am not as old as Methusala but our school textbooks were)
syhprum
-
the epr paradox has to do with measuring two correlated spins simultaneously. i don't think bell's theorem contradicts the existance of spin all together.
-
quote:
Originally posted by bostjan
the epr paradox has to do with measuring two correlated spins simultaneously. i don't think bell's theorem contradicts the existance of spin all together.
Please, explain the result of Stern-Gerlach experiment I have showed you in my post, in terms of spin as a real property of an atom or electron or else.
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Just read the paper you posted, Bell's original paper, and the EPR paradox.
The Stern-Gerlach experiment shows that spin is real and observable A Stern-Gerlach device only measures the z component of spin (where z is along the axis of the beam. If the spin is one half, the beam splits into two parts, one with the z-component of spin positive and the other negative.
Bell's theorem deals with hidden variables (the hidden variable being the correlation between the spin states of two separate particles heading in opposite direction). Bell showed that these hidden variables are illogical (those variables that relate the two spin states). The reason Stern-Gerlach is mentioned is because it is the apparatus used to measure spin.
Quantum spin states are very real. See Scientific American 241, 158 (Nov. 1979) by B d'Espagnat.
-
quote:
Originally posted by bostjan
Just read the paper you posted, Bell's original paper, and the EPR paradox.
The Stern-Gerlach experiment shows that spin is real and observable A Stern-Gerlach device only measures the z component of spin (where z is along the axis of the beam. If the spin is one half, the beam splits into two parts, one with the z-component of spin positive and the other negative.
Bell's theorem deals with hidden variables (the hidden variable being the correlation between the spin states of two separate particles heading in opposite direction). Bell showed that these hidden variables are illogical (those variables that relate the two spin states). The reason Stern-Gerlach is mentioned is because it is the apparatus used to measure spin.
Quantum spin states are very real. See Scientific American 241, 158 (Nov. 1979) by B d'Espagnat.
I would like to understand if you agree with me or not and, if not, exactly where, about these (mine) statements:
1.If a particle's spin x-component is a real property of the particle, then measuring its z-component should not affect the previous one; otherwise it's not a property of the particle alone, at least, but of the entire system particle-detector .
2.If that it's a real, intrinsic property of the particle, then it should behave as an "hidden" variable.
3.Bell's theorem showed that the hidden variable hypothesis gives results inconsistent with quantum mechanics results. Specifically, according hidden variable hypothesis, the result is something like:
N1 < N2, while, according Q.M., the result is N1 = A, where A > N2.
4.Experimental results have shown that the results agree with Q.M.
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We are talking here about a quantum level measurement. Because of the uncertainty principle you cannot make any measurements without affecting them.
to measure the spin of an electron in any direction you create a field that will turn the spin in that direction. if the spin is not in that direction it turns and you detect a photon that reperesents the energy used in turning the spin id does not turn and nothing happens and you do not detect the photon either way the spins end up aligned in the way your apparatus has been set to them
Learn, create, test and tell
evolution rules in all things
God says so!
-
quote:
Originally posted by Soul Surfer
We are talking here about a quantum level measurement. Because of the uncertainty principle you cannot make any measurements without affecting them.
to measure the spin of an electron in any direction you create a field that will turn the spin in that direction. if the spin is not in that direction it turns and you detect a photon that reperesents the energy used in turning the spin id does not turn and nothing happens and you do not detect the photon either way the spins end up aligned in the way your apparatus has been set to them
I knew I was exploring an undermined ground here!
Please don't shoot at me for my statements! (I'm joking, of course).
I'm just trying to understand better; I don't even have a degree in physics (I studied it for 3 years and then I had to stop), so, forgive me if I say something silly.
When you say "...to measure the spin of an electron in any direction you create a field that will turn the spin in that direction..." you are assuming, I presume, that electrons have this intrinsec property that you call spin?
If your answer is "yes", mine is: no, because, in this case, it would be an hidden variable.
Maybe I'm making a mistake.
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1. It is, indeed a property of the measurement. Theoretical spin states can vary in all sorts of ways, but measuring the spin in a certain direction will only show you one integral or half-integral state (i.e. +1/2 or -1/2 for an electron).
2. Spin is not a hidden variable, it is measured directly by a Stern-Gerlach apparatus and although it is a property of a quantum particle, it is quite real, much like momentum or charge. Think of charge as an intrinsic property of a particle with integer values.
3. The hidden variables in question are about finding a way to determine the measured spin states, in effect taking away all randomization of the measurement. These are some unseen degrees of freedom, that were postulated by Einstein, Bohm, de Broglie, and Bethe, but are regarded by a majority of physicists to be debunked now, thanks to John Bell and a plethora of experiments to back him up.
4. Yes. (S Freedman and J Clauser, Phys Rev Lett 28, 938 (1978))
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quote:
Originally posted by bostjan
1. It is, indeed a property of the measurement. Theoretical spin states can vary in all sorts of ways, but measuring the spin in a certain direction will only show you one integral or half-integral state (i.e. +1/2 or -1/2 for an electron).
2. Spin is not a hidden variable, it is measured directly by a Stern-Gerlach apparatus and although it is a property of a quantum particle, it is quite real, much like momentum or charge. Think of charge as an intrinsic property of a particle with integer values.
3. The hidden variables in question are about finding a way to determine the measured spin states, in effect taking away all randomization of the measurement. These are some unseen degrees of freedom, that were postulated by Einstein, Bohm, de Broglie, and Bethe, but are regarded by a majority of physicists to be debunked now, thanks to John Bell and a plethora of experiments to back him up.
4. Yes. (S Freedman and J Clauser, Phys Rev Lett 28, 938 (1978))
Ok, thank you for your explanation, bostjan.
I'm still puzzled, however: what does "(The hidden variables in question are about finding a way)...to determine the measured spin states..." exactly mean?