Why against Stern-Gerlach experiment photons are said to be spin 1?
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From: Igor on 23 Nov 2009 10:09 On Nov 20, 3:16 am, "Y.Porat" <y.y.po...(a)gmail.com> wrote: > On Nov 19, 11:08 pm, Igor <thoov...(a)excite.com> wrote: > > > > > > > On Nov 19, 1:43 pm, "Y.Porat" <y.y.po...(a)gmail.com> wrote: > > > > On Nov 19, 7:14 pm, Igor <thoov...(a)excite.com> wrote: > > > > > On Nov 18, 10:55 am, Jarek Duda <duda...(a)gmail.com> wrote: > > > > > > Spin corresponds to magnetic dipole moment of particle, > > > > > This is not true if a particle has no internal charge distribution. > > > > So your initial statement is false for a photon. > > > > > Besides, you've gotten it backwards. The magnetic dipole moment > > > > depends on spin and charge. You need a current loop. > > > > -------------- > > > Hi parrot > > > you speak about spin > > > while you dont know ***and dont mind*** > > > how and why it is done > > > you could as well say that it is done by > > > witches on brooms > > > the same with your Higgs Bosons > > > > Y.P > > > -------------------------- > > > Crawl back under your rock and let the big insects discuss physics. > > ------------------ > (:-) > you have some greetings from your > Higgs Bosons > and from your 3 quarks per Proton > and every day another quark story etc > > got is IMBECILE MATHEMATICIAN crook PARROT ???!! > you cant cheat every body forever !! > > Y.P > ----------------------- Just another boring attack from an imbecile. Nothing of susbstance here. If you want to attack the foundations of modern physics, you could at least be more creative in your pathetic attempts. Reading one of your posts is a lot like eating vanilla ice cream while watching Ozzie and Harriet.
From: Jarek Duda on 23 Nov 2009 10:16 > According to the Standard Model, the neutrino is a fundamental > chargeless particle, so it should not have a magnetic dipole moment. > If it ever was discovered that the neutrino has a finite magnetic > dipole moment, it would be back to the drawing board. I've looked at a few papers and they were rather saying something different... http://arxiv.org/abs/hep-ph/0601113
From: cjcountess on 23 Nov 2009 12:26 Electrons ARE "accelerated photons". They are the high end of the EM spectrum, which is not only the electromagnetic, but the energy/matter spectrum, where (E=hf/c^2) = (E=mc^2), or as deBroglie stated, (E=hf=mc^2). See:http://docs.google.com/Doc?id=dsn5q6f_101hgtjv9fb&hl=en Conrad J Countess
From: Darwin123 on 24 Nov 2009 00:14 On Nov 18, 10:55 am, Jarek Duda <duda...(a)gmail.com> wrote: > Spin corresponds to magnetic dipole moment of particle, so in > inhomogeneous magnetic field their trajectories are modified > accordingly to alignment of its spin axis (Stern-Gerlach experiment). > But as I know, photon's trajectories aren't changed in strong magnetic > fields, what suggests that they should be spin 0... Spinning does not automatically produce a magnetic field. The fact of having angular momentum is not by itself a reason for having a magentic dipole. Spinning only produces a magnetic field if electric charges are moved around in a circle. Electrons have a nonzero electric charge. Therefore, an electron spin is associated with a magnetic field. Photons have a net zero charge. Not only that, photons are not composed of other fundamental particles with an electric charge. Neutrons are a particular case. Like photons, neutrons have no net electric charge. However, every photon is comprised of three quarks. The quarks are electrically charged. So the moving quarks in the neutron do generate a magnetic dipole. We know neutrons have three qarks by scattering experiments. Photons have not been shown to be comprised of smaller particles. > > So I wanted to ask why in 'common knowledge' photons are said to be > spin 1 particles? Light can carry angular momentum. Circularly polarized light always has positive angular momentum. There is the classical analog to the photons spin. However, circularly polarized light is not associated with an electric charge current. > > I've asked this question a few times in different discussions, like to > Uncle Alhttp://groups.google.com/group/sci.physics/browse_thread/thread/4c991... > and I didn't get any concrete argument. Attraction/repellence can be > transferred even by waves in water. Very good. Water is an excellent example of why you are wrong. Water waves on the surface are always associated with eddies. Eddies are localized areas of "spinning water." However, waves are usually unassociated with magnetic fields. Have you ever asked yourself why waves on the ocean are not associated with magnetic fields? Flowing water can carry angular momentum. If you stir a cup of water, you will observe nonzero angular momentum in the cup of water. However, the cup of water will be usually unattracted to a magnet because the water does not contain an electric charge. Look up magnetiodynamics of electrolytic solutions. It is possible to get an electric current out of moving water if salt is added to the water. The salt ions have nonzero electric charges. So a salt water solution is somewhat analogous to a neutron. There are also ways to get magnetic fields out of convenction currents in a conducting fluid. As photons do not consist of electrical conductors, nor do they have convective currents, it should be clear why they don't have convective magnetic fields. So that is it. An electron has an electric charge and a photon doesn't. The Stern Gerlach experiment was done with electrons, not photons. The problem is not with the physics establishment. You neglected to ask whether spinning was always associated with magnetic dipoles. The answer to your question is extremely simple. Spinning is NOT always associated with magnetic dipoles. I predict that you will not accept my simple explanation. I speculate you will not even address this post. You will keep repeating the flase statement that no one answered your question.
From: Darwin123 on 24 Nov 2009 00:36
On Nov 20, 12:29 am, Jarek Duda <duda...(a)gmail.com> wrote: > Robert - the fact that sometimes QM can predict with p=1 still makes > I think that photon is overestimated in modern physics - for example > try to imagine that electron goes around proton because of constant > exchange of spin 1 photons ... > If photon could carry spin, it would split in stern-Gerlach ... No, because the photon doesn't have electric charge. You can't make a magnetic dipole by spinning an object without electric charge. Really, that is the answer to the original question. A photon doesn't have a magnetic dipole because it does not have an electric charge. We can even extend this: A photon is not an "accelerated electron" because it contains no electric charge. An electron no matter how accelerated has an electric charge. A photon does not have an electric charge. The angular momentum of a photon can be measured using methods that do not involve the Stern Gerlach experiment. Polarization is the classical analog to the spin of a photon. However, there is no magnetic dipole associated with polarization. Electrons have a negative charge. If one spins a negative charged particle, one gets a magnetic dipole. The discovery of a magnetic dipole in an electron, via the Stern Gerlach experiment, automatically raised the possibility that the electron was spinning. it was already known that light could carry angular momentum, hence the "photon" was spinning. If the magnetic field had split a light beam the same way, they would have been forced to look for a hidden electric charge in the photon. This is my second post on the subject today. I predict that you will either ignore both posts, or change the subject in an angry way. However, I have answered your question. |