Moderator: Flannel Jesus
http://www.lbl.gov/abc/wallchart/chapters/05/1.html wrote:One consequence of the half-integer spins of neutrons and protons is that nuclei with an odd number of nucleons must have half-integer angular momentum, while nuclei having an even number of nucleons must have integer angular momentum (in units). Another consequence is quite bizarre: objects with half-integer spin must be rotated by 720° (not 360°) before they return to their initial state! This peculiar behavior has been demonstrated using very slow (ultracold) spin-oriented neutrons from a reactor, which are split into two beams. In one beam the neutrons are rotated about an axis along their direction of motion through some angle, and then the beams are recombined. It is found that when the rotation angle is 360°, the combined beams are out of phase and cancel, (meaning that they are shifted away from the detector) while after 720° of rotation the beams are in phase and reinforced (meaning that they show a large signal at the detector). A rotation of 720° is needed to put the neutrons back in their original state.
http://en.wikipedia.org/wiki/Spin_quantum_number wrote:In atomic physics, the spin quantum number is a quantum number that parameterizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. The spin quantum number is the fourth of a set of quantum numbers (the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number) which describe the unique quantum state of an electron and is designated by the letter s.
Anthem wrote:It's the spin about its own axis, north.
http://en.wikipedia.org/wiki/Spin_quantum_number wrote:In atomic physics, the spin quantum number is a quantum number that parameterizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. The spin quantum number is the fourth of a set of quantum numbers (the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number) which describe the unique quantum state of an electron and is designated by the letter s.
And where are you getting your information about electrons 'diving down' to the nucleus?
north wrote:not sure what you mean by " own axis "
north wrote:a few years ago I got into non-destructive testing , there is maths invovled , and one of the instructure's was from Dafasco steel plant in Hamilton , Ontario
they had a a small , particle collider ( wow , who knew , and I only lived an hours drive from there !!!)
he told me of the electron diving down towards the proton
Anthem wrote:It's a way to describe the angular momentum of a particle. What causes it? No idea. Maybe some particle physicist can give an explanation.
The other part of your question is about entanglement. It's not really instant communication.
" Another consequence is quite bizarre: objects with half-integer spin must be rotated by 720° (not 360°) before they return to their initial state!
"It is found that when the rotation angle is 360°, the combined beams are out of phase and cancel, (meaning that they are shifted away from the detector) while after 720° of rotation the beams are in phase and reinforced (meaning that they show a large signal at the detector). A rotation of 720° is needed to put the neutrons back in their original state.'
Jakob wrote:Is spin also applicable to the angular momentum of the earth orbiting the sun?
Jakob wrote:Ok, but it seems instant compared to the speed of light.
Observations pertaining to entangled states appear to conflict with the property of relativity that information cannot be transferred faster than the speed of light. Although two entangled systems appear to interact across large spatial separations, the current state of belief is that no useful information can be transmitted in this way, meaning that causality cannot be violated through entanglement. This is the statement of the no-communication theorem.
Even if information cannot be transmitted through entanglement alone, it is believed[who?] that it is possible to transmit information using a set of entangled states used in conjunction with a classical information channel. This process is known as quantum teleportation. Despite its name, quantum teleportation may still not permit information to be transmitted faster than light, because a classical information channel is required to complete the process.
In addition experiments are underway to see if entanglement is the result of retrocausality.[4][5]
Jakob wrote:Cool!
Jakob wrote:This attribute of elementary particle/waves enables properties to communicate/travel (virtually) instantly.
What causes it?
Anthem wrote:Why do you think fluid flow is a good comparison?
http://en.wikipedia.org/wiki/Quantum_spin#Spin_direction wrote:It turns out that the spin vector is not very useful in actual quantum mechanical calculations, because it cannot be measured directly — sx, sy and sz cannot possess simultaneous definite values, because of a quantum uncertainty relation between them. However, for statistically large collections of particles that have been placed in the same pure quantum state, such as through the use of a Stern-Gerlach apparatus, the spin vector does have a well-defined experimental meaning: It specifies the direction in ordinary space in which a subsequent detector must be oriented in order to achieve the maximum possible probability (100%) of detecting every particle in the collection. For spin-1/2 particles, this maximum probability drops off smoothly as the angle between the spin vector and the detector increases, until at an angle of 180 degrees — that is, for detectors oriented in the opposite direction to the spin vector—the expectation of detecting particles from the collection reaches a minimum of 0%.
As a qualitative concept, the spin vector is often handy because it is easy to picture classically. For instance, quantum mechanical spin can exhibit phenomena analogous to classical gyroscopic effects. For example, one can exert a kind of "torque" on an electron by putting it in a magnetic field (the field acts upon the electron's intrinsic magnetic dipole moment — see the following section). The result is that the spin vector undergoes precession, just like a classical gyroscope.
Mathematically, quantum mechanical spin is not described by vectors as in classical angular momentum, but by objects known as spinors. There are subtle differences between the behavior of spinors and vectors under coordinate rotations. For example, rotating a spin-1/2 particle by 360 degrees does not bring it back to the same quantum state, but to the state with the opposite quantum phase; this is detectable, in principle, with interference experiments. To return the particle to its exact original state, one needs a 720 degree rotation. A spin-zero particle can only have a single quantum state, even after torque is applied. Rotating a spin-2 particle 180 degrees can bring it back to the same quantum state and a spin-4 particle should be rotated 90 degrees to bring it back to the same quantum state. The spin 2 particle can be analogous to a straight stick that looks the same even after it is rotated 180 degrees and a spin 0 particle can be imagined as sphere which looks the same after whatever angle it is turned through.
Xunzian wrote:Isn't is just a term they've applied to a particular quantum state? I'm no physicist, but isn't it kind of like asking what exactly are "latitude and longitude"? They certainly can be used to correspond to real places but latitude and longitude are just mathematical operations used to identify those places. What they are terms in a mathematical model. A big, nasty mathematical model. Describing them beyond the language of math is pretty difficult because, well, that is where they exist. And translating math into English or any other spoken human language can be pretty difficult.
Anthem wrote:Observations pertaining to entangled states appear to conflict with the property of relativity that information cannot be transferred faster than the speed of light. Although two entangled systems appear to interact across large spatial separations, the current state of belief is that no useful information can be transmitted in this way, meaning that causality cannot be violated through entanglement. This is the statement of the no-communication theorem.
Even if information cannot be transmitted through entanglement alone, it is believed[who?] that it is possible to transmit information using a set of entangled states used in conjunction with a classical information channel. This process is known as quantum teleportation. Despite its name, quantum teleportation may still not permit information to be transmitted faster than light, because a classical information channel is required to complete the process.
In addition experiments are underway to see if entanglement is the result of retrocausality.
Xunzian wrote:Isn't is just a term they've applied to a particular quantum state? I'm no physicist, but isn't it kind of like asking what exactly are "latitude and longitude"? They certainly can be used to correspond to real places but latitude and longitude are just mathematical operations used to identify those places. What they are terms in a mathematical model. A big, nasty mathematical model. Describing them beyond the language of math is pretty difficult because, well, that is where they exist. And translating math into English or any other spoken human language can be pretty difficult.
All known fermions are particles with half-integer spin: as an observer circles a fermion (or as the fermion rotates 360° about its axis) the wavefunction of the fermion changes sign. In the framework of nonrelativistic quantum mechanics, this is a purely empirical observation. However, in relativistic quantum field theory, the spin-statistics theorem shows that half-integer spin particles cannot be bosons and integer spin particles cannot be fermions.[2]
In large systems, the difference between bosonic and fermionic statistics is only apparent at large densities when their wave functions overlap. At low densities, both types of statistics are well approximated by Maxwell-Boltzmann statistics, which is described by classical mechanics.
Farsight wrote:As for what's spinning, the electron is made via pair production. You start with light. You can then destroy the electron via annihilation, and the result is light. Basically what's spinning, is light.
Jakob wrote:Farsight wrote:As for what's spinning, the electron is made via pair production. You start with light. You can then destroy the electron via annihilation, and the result is light. Basically what's spinning, is light.
Greetings Lord Farsight. Thanks for this long awaited response.
Is it correct to say that light is made into an electron through the mechanism of spin? That's what I get out of this at first glance. That light is trapped into a self referring path, by splitting in two and revolving around itself, so to speak. Confining it to a more or less set location, making it into something resembling a particle, by inter-inter-interference.
Jakob wrote:References! Names! You can drop many, I have to admit it. I could also drop them. But it's not fame I'm after, not association with famous people, but to lay bare the simplicity of the mechanism so I can understand it.
I am also in the dark about pair production. This seems to be the mechanism which underlies spin, the method by which light is transformed from a singularity into a duality, and so takes on substance. It could be a metaphor for the entire human condition. The pure body of light, Adam splitting in two becoming a pair and subsequently being bound to matter, revolving around itself, and revolving together around a core. Human interpretation, that's all it is on whatever level. But how does it happen?
north wrote:Jakob wrote:References! Names! You can drop many, I have to admit it. I could also drop them. But it's not fame I'm after, not association with famous people, but to lay bare the simplicity of the mechanism so I can understand it.
spin is the resultant of confined energy and/or movement , within a confined space
I am also in the dark about pair production. This seems to be the mechanism which underlies spin, the method by which light is transformed from a singularity into a duality, and so takes on substance. It could be a metaphor for the entire human condition. The pure body of light, Adam splitting in two becoming a pair and subsequently being bound to matter, revolving around itself, and revolving together around a core. Human interpretation, that's all it is on whatever level. But how does it happen?
yet the proton spins in the hyrogen atom
where there is no electron
Return to Science, Technology, and Math
Users browsing this forum: Yahoo [Bot]