Jump to content

Recommended Posts

But, like spin (this is a thread on spin, after all), this is not motion-related. Electrons in atoms do not have trajectories. The wave function solutions (more complicated than sinusoids, but still spatially periodic) are stationary states with respect to time.

 

 

What I'm getting at is that this is only half of the metaphorical battle. You have this mental model of how it works, but you still need to test that model to be sure. Otherwise you can end up with a model that fails when you try and apply it.

 

 

O.K. I get it.

 

Well I have run a series of tests over the years.( To endorse my mental model ) I will get them together , and pop them up here. See what you think or anybody else thinks .

Edited by Mike Smith Cosmos

Share this post


Link to post
Share on other sites

Spin is a Vector quantity of single particles i.e; A photon can spin up or down so fast (Although speed isn't always of concern) or a photon with a spin on a 45 degree angle could be considered in a superposition in Quantum computing, between a 1 and a 0 and would be written |0> + |1>.

 

 

[Edit] I realized I needed to add this - Spin is based on frequency and electromagnetic fields, evidence of this is that we can use magnetic fields and certain frequencies to alter the spin of a particle. When spin is referred to the spin and direction the particle is spinning in the particles respective magnetic field are what is meant.

Edited by howlingmadpanda

Share this post


Link to post
Share on other sites

Spin is a Vector quantity of single particles i.e; A photon can spin up or down so fast (Although speed isn't always of concern) or a photon with a spin on a 45 degree angle could be considered in a superposition in Quantum computing, between a 1 and a 0 and would be written |0> + |1>.

 

It's actually a spinor for fermions, not a vector. But the difference isn't really that important if you're just trying to get a feel for it.

Edited by elfmotat

Share this post


Link to post
Share on other sites

What a lot of varied answers and ideas about spin. Here I will say what spin is and also add something entirely different about spin.

 

Of course spin was discovered in 1922 by Stern and Gerlach.

 

Dirac was able to formulate spin using relativistic quantum mechanics IIn all derivations of spin you will see they depend upon there being a magnetic probe present. That is spin can only be formulated within quantum mechanics when an interacting probe is present. (That is because quantum mechanics is s theory of measurement).

 

This leads to the usual Lorentz invariant spin being depicted as intrinsic angular momentum, with magnitude of 1/2 h-bar, and considered to be a point particle with a single axis of quantization. It obeys su(2) algebra, and has group property of SU(2).

 

If you measure spin, like Stern and Gerlach, then you seem two pure states and these can be viewed as antipodal points on a Bloch Sphere.

 

All very nice and all seems to work.

 

But does it. Quantum mechanics fails to predict if a single particle with spin, say a silver atom, will be deflected up or down. That is quantum mechanics is indeterministic. Only after a statistically large number of particles have passed the Stern Gerlach filter does quantum mechanics predict the results (quantum mechanics is statistical). Finally, is you take an entangled singlet state and do correlation experiments on them, the usual conclusion is that Nature is non-local.

 

I am just submitting a paper to Phys Rev A that makes a small change to spin, with far reaching consequences. Assume a spin in ISOLATION, has two axes of quantization (that is structure) rather than one. In that case, it can be shown that not only is Nature local and real, but also deterministic. The 2D spin model reproduced the quantum correlation that leads to violation of Bell's Inequalities without entanglement, and agrees with the usual spin in the presence of a probe field.

 

So my findings are that spin is different in the presence of a probe (when you measure) and in the absence of a probe (in free flight).

 

There is more on my blog, and the research paper will soon be available there.

Edited by imatfaal
Link removed by mod per rule 7

Share this post


Link to post
Share on other sites

 

All very nice and all seems to work.

 

But does it. Quantum mechanics fails to predict if a single particle with spin, say a silver atom, will be deflected up or down. That is quantum mechanics is indeterministic. Only after a statistically large number of particles have passed the Stern Gerlach filter does quantum mechanics predict the results (quantum mechanics is statistical).

But that's only because you have an ensemble with both spins present, or in a superposition of the spin states. If you spin-polarize the sample, i.e. you know the spin orientation, you know what direction it will deflect. Your statement does not make this distinction.

Share this post


Link to post
Share on other sites

What a lot of varied answers and ideas about spin. Here I will say what spin is and also add something entirely different about spin.

 

There seems to be a determined effort to keep "Spin" well veiled in the realm of non visualization.

 

Why is there such a zealous cause to keep spin in a - ' not spin as we know spin' - where both the name " Spin " and the term " angular momentum " .have suggestions of some form of rotational activity, all-be-it that it is not thought to be quite like a spinning top. ? Can we totally exclude any form of partial (circular, rotational, oscillatory ) even if such movement may be quite different from what we normally experience in the macro world.?

Share this post


Link to post
Share on other sites

There seems to be a determined effort to keep "Spin" well veiled in the realm of non visualization.

 

Why is there such a zealous cause to keep spin in a - ' not spin as we know spin' - where both the name " Spin " and the term " angular momentum " .have suggestions of some form of rotational activity, all-be-it that it is not thought to be quite like a spinning top. ?

 

At a certain point trying to visualize what's going on isn't helpful, and can often be hurtful - a lot of misconceptions can spring up. As far as physics is currently concerned, particles are point-objects. They don't have any extended structure, so it doesn't make any sense to think of them as spinning like a top.

 

Can we totally exclude any form of partial (circular, rotational, oscillatory ) even if such movement may be quite different from what we normally experience in the macro world.?

 

I'm by no means familiar with the subject, but in String Theory spin is associated with a type of rotation motion of the string. The wikipedia had this to say:

 

Spin: each particle in quantum field theory has a particular spin s, which is an internal angular momentum. Classically, the particle rotates in a fixed frequency, but this cannot be understood if particles are point-like. In string theory, spin is understood by the rotation of the string; For example, a photon with well-defined spin components (i.e. in circular polarization) looks like a tiny straight line revolving around its center.

Share this post


Link to post
Share on other sites

There seems to be a determined effort to keep "Spin" well veiled in the realm of non visualization.

 

Why is there such a zealous cause to keep spin in a - ' not spin as we know spin' - where both the name " Spin " and the term " angular momentum " .have suggestions of some form of rotational activity, all-be-it that it is not thought to be quite like a spinning top. ? Can we totally exclude any form of partial (circular, rotational, oscillatory ) even if such movement may be quite different from what we normally experience in the macro world.?

 

We don't want to invent more terminology, so we simply present the caveat that QM spin is not classical, physical motion. It's not really that much of a burden, because there are other bits of QM that have a classical analog and yet are not represented by classical, physical motion.

Share this post


Link to post
Share on other sites

We don't want to invent more terminology, so we simply present the caveat that QM spin is not classical, physical motion. It's not really that much of a burden, because there are other bits of QM that have a classical analog and yet are not represented by classical, physical motion.

I do appreciate that at the quantum level are as different as ' chalk and cheese'. But I still think if you have Angular momentum as an actual quantity , there surely must be some 'angle going through process' of some sort , which must be curve y or partial circle y of some sort . Also we have the magnetic moment caused by something moving curve y one way or another.

 

maybe electrons move curve y all the time in their cloud like orbitals..

 

 

post-33514-0-23900600-1366926361_thumb.jpg

 

Maybe there is enough angles during the cloud paths to give the angular momentum ?

Edited by Mike Smith Cosmos

Share this post


Link to post
Share on other sites

I do appreciate that at the quantum level are as different as ' chalk and cheese'. But I still think if you have Angular momentum as an actual quantity , there surely must be some 'angle going through process' of some sort , which must be curve y or partial circle y of some sort . Also we have the magnetic moment caused by something moving curve y one way or another.

 

maybe electrons move curve y all the time in their cloud like orbitals..

 

 

attachicon.gifCurve y electron shells.jpg

 

Maybe there is enough angles during the cloud paths to give the angular momentum ?

 

 

Fine — prove it. Show the trajectory has the right angular momentum, and/or devise an experiment to test it.

Share this post


Link to post
Share on other sites

I do appreciate that at the quantum level are as different as ' chalk and cheese'. But I still think if you have Angular momentum as an actual quantity , there surely must be some 'angle going through process' of some sort , which must be curve y or partial circle y of some sort . Also we have the magnetic moment caused by something moving curve y one way or another.

 

maybe electrons move curve y all the time in their cloud like orbitals..

 

 

attachicon.gifCurve y electron shells.jpg

 

Maybe there is enough angles during the cloud paths to give the angular momentum ?

 

I'm confused now. Do you want to know about orbital angular momentum, or about spin? Because they're separate concepts. An electron has spin regardless of whether it's bound to an atom.

Share this post


Link to post
Share on other sites

Fine — prove it. Show the trajectory has the right angular momentum, and/or devise an experiment to test it.

 

Yes. Well I have devised several types of trajectories. I have built some experiments to demonstrate the principles of the proposed phenomenon, I have done some of the maths And as I mentioned a few posts ago , that I would try to put it together. Which I will, provided I do not get run over by a bus, or end up in concrete wellington boots..

 

I'm confused now. Do you want to know about orbital angular momentum, or about spin? Because they're separate concepts. An electron has spin regardless of whether it's bound to an atom.

 

Yes, well there are two potential origins of curve y motion as you say . 1 ) Integral spin 2) movement about the atom both having attributes of circular motion, in one way shape or another. I know you guys don't particularly like it, but the planet/ sun system or the sun/ galaxy system are typical models if that is a way of looking at it. eg stars spin and at the same time move with the galaxy about the galaxy core in a huge circle.

 

I would like to think the electron has / had both. When free - some form of curve y spin all be it , different to the astronomical spin, - and when in association with a nucleus , namely in an atom , another complex type of curve y movement which has angular implications.whilst in its orbitals or in its energy band.

 

I

Share this post


Link to post
Share on other sites

Yes, well there are two potential origins of curve y motion as you say . 1 ) Integral spin 2) movement about the atom both having attributes of circular motion, in one way shape or another. I know you guys don't particularly like it, but the planet/ sun system or the sun/ galaxy system are typical models if that is a way of looking at it. eg stars spin and at the same time move with the galaxy about the galaxy core in a huge circle.

 

I would like to think the electron has / had both. When free - some form of curve y spin all be it , different to the astronomical spin, - and when in association with a nucleus , namely in an atom , another complex type of curve y movement which has angular implications.whilst in its orbitals or in its energy band.

 

I'm not really sure what you're getting at. Do you accept that all data at this time suggests particles are point-objects, as predicted by the Standard Model? If so, what exactly is your point? Because point objects cannot, by definition, be rotating extended objects. If you don't accept this, did you read the wikipedia quote I provided above?

Share this post


Link to post
Share on other sites

I know you guys don't particularly like it, but the planet/ sun system or the sun/ galaxy system are typical models if that is a way of looking at it. eg stars spin and at the same time move with the galaxy about the galaxy core in a huge circle.

 

The reason we "don't like it" is because it doesn't give the answer consistent with what we observe. The angular momentum of the S state in atoms is zero. That's not an orbit of moving in a circle.

Share this post


Link to post
Share on other sites

I'm not really sure what you're getting at. Do you accept that all data at this time suggests particles are point-objects, as predicted by the Standard Model? If so, what exactly is your point? Because point objects cannot, by definition, be rotating extended objects. If you don't accept this, did you read the wikipedia quote I provided above?

 

No. I find it difficult to accept ( i am probably wrong, I don't know ) point like particles (i thought all sorts of infinities appeared when r=0. unless the point is not r=0

 

Yes I have looked at the wikepedia link you gave. I am not sure I am up to digesting it all at this stage.

I think the best I can do is explain where I got to in my experiments and thoughts . You either tear it all to shreds or we take it further. It starts back in the 1970's ....... to today ( My .... thats 40 years , more than the age of most of the guys on this forum )

 

I need to go out and paint a picture of a pretty flower at an art class , It will hopefully keep me sane .

Edited by Mike Smith Cosmos

Share this post


Link to post
Share on other sites

But that's only because you have an ensemble with both spins present, or in a superposition of the spin states. If you spin-polarize the sample, i.e. you know the spin orientation, you know what direction it will deflect. Your statement does not make this distinction.

 

Yes of course: if the beam is prepared as polarized in one direction, we know how it will be deflected when the filter is in the same direction, but I meant that the source is random, so every photon or silver atom emerges randomly oriented. In that case there is no way to predict if one particle will deflect up or down. That is an example of quantum indeterminism. Only after a statistically large number have passed the filter does quantum mechanics predict the state.

 

Could also take a polarized beam, say z, and put it through filter oriented in some other way. From that polarized beam, you cannot predict how it will deflect.

 

So this is a situation where quantum mechanics fails.

Edited by Bryan Sanctuary

Share this post


Link to post
Share on other sites

Yes of course: if the beam is prepared as polarized in one direction, we know how it will be deflected when the filter is in the same direction, but I meant that the source is random, so every photon or silver atom emerges randomly oriented. In that case there is no way to predict if one particle will deflect up or down. That is an example of quantum indeterminism. Only after a statistically large number have passed the filter does quantum mechanics predict the state.

 

Could also take a polarized beam, say z, and put it through filter oriented in some other way. From that polarized beam, you cannot predict how it will deflect.

 

So this is a situation where quantum mechanics fails.

 

QM fails to be predictive for an individual case, yes, but the theory itself does not fail.

Share this post


Link to post
Share on other sites

I need to go out and paint a picture of a pretty flower at an art class , It will hopefully keep me sane .

 

Been out, Done that, Here is the 'T' shirt .

 

 

post-33514-0-29860000-1367005558_thumb.jpg

 

Original

 

post-33514-0-29226800-1367005624_thumb.jpg

 

Next Art Project

 

post-33514-0-64466100-1367005672_thumb.jpg

 

 

Keeps me sane . However there will be a relevance to all these Flowers .

 

Probability, Statistics and Dragon Flies. And the way Nature uses 'MOLDS' to solve statistical Probability issues. Rather than deep seated , embedded , maths to act causally.

Edited by Mike Smith Cosmos

Share this post


Link to post
Share on other sites

Unless the experiment uses actual electrons in atomic orbitals, I don't see how this shows what you were claiming. We already know that macroscopic/classical physics does not behave like QM, so a classical experiment sheds no light on how QM systems behave.

 

Macroscopic Physics is a RESULT of the reality and behavior of Quantum Mechanics. Other than this the two have very little if anything in common as far as association of particle/wave behavior and Macro/Gravity/Celestial Body actions and constructs.

 

It is like trying to compare a Bicycle Tire Pump that represents QM...to the Bicycle...representing the Macro scale.

 

Split Infinity

Share this post


Link to post
Share on other sites

!

Moderator Note

Some tangential material has been split

The duck and dog model (no that's not a typo) http://www.scienceforums.net/topic/74668-can-principles-in-the-macro-level-give-insights-into-the-quantum-level-split-from-spin/


Speculative tuning fork model discussion http://www.scienceforums.net/topic/74675-tuning-fork-model-of-spin/

Speculative spin model from robinpike http://www.scienceforums.net/topic/74687-model-for-spin/

Share this post


Link to post
Share on other sites

!

Moderator Note

Some tangential material has been split

 

The duck and dog model (no that's not a typo) http://www.scienceforums.net/topic/74668-can-principles-in-the-macro-level-give-insights-into-the-quantum-level-split-from-spin/

 

 

Speculative tuning fork model discussion http://www.scienceforums.net/topic/74675-tuning-fork-model-of-spin/

 

Speculative spin model from robinpike http://www.scienceforums.net/topic/74687-model-for-spin/

 

 

 

I think Spin as an angular momentum orbital and integral spin should be kept center stage or this very fundamental principal of the nature of particles , particularly the electron will be lost in fragmentation.

 

Spin per Wikipedia http://www.wikipedia.org/wiki/Angular_momentum

 

 

Electron Spin Quantum Mechanics

Edited by swansont
fix url

Share this post


Link to post
Share on other sites

 

Spin as an angular momentum orbital and integral spin

From Wikipedia, the free encyclopedia

 

 

 

. Do these Spins interact , conserve or otherwise with the Higgs mechanism.?

 

. Has this been investigated with the recent CERN experiments ?

Edited by Mike Smith Cosmos

Share this post


Link to post
Share on other sites
Studies of the spin and parity quantum numbers of the Higgs boson are presented, based on proton-proton collision data collected by the ATLAS experiment at the LHC.

 

The main data source of the lhc - slamming protons into protons, ATLAS is one of two detectors that have data that provides evidence for the higgs

 

The Standard Model spin-parity JP = 0+ hypothesis is compared with alternative hypotheses

 

 

We work by comparing a hypothesis against alternatives - assume one and work out what chance there is of random fluctuations causing the data we have

 

using the Higgs boson decays H->gamma gamma,

 

 

Different ways of the shortlived higgs decaying - Higgs to two photons

 

H -> ZZ -> 4 leptons

 

 

Higgs to two Z-bosons (one is virtualish) and then to 4 leptons

 

and H->WW -> l nu l nu,

 

ditto with W-bosons to leptons and neutrinos

 

as well as the combination of these channels. The analysed dataset corresponds to an integrated luminosity of 20.7 fb-1 collected at a centre-of-mass energy of sqrt(s) = 8 TeV. For the H -> ZZ -> 4-lepton decay mode the dataset corresponding to an integrated luminosity of 4.6 fb-1 collected at sqrt(s) = 7 TeV is added.

 

we can only spot the Higgs through its decay products - and these are the easiest to measure. The amount of collection in total and per decay and the energy of the colliding particles

 

 

The data are compatible with the Standard Model JP = 0+ quantum numbers for the Higgs boson, whereas all alternative hypotheses studied in this letter, namely some specific JP = 0-; 1+; 1-; 2+ models, are excluded at confidence levels above 97.8%.

 

 

 

They looked at many different models (with different spins and parities) and worked out what the chances were that the data could fit the predictions of those models - it was very low. BTW the 0 is the spin the plus/minus is the parity - see here

 

This exclusion holds independently of the assumptions on the coupling strengths to the Standard Model particles and in the case of the JP = 2+ model, of the relative fractions of gluon-fusion and quark-antiquark production of the spin-2 particle.

 

 

 

Stating how the experiment avoids one or twp pitfalls

 

The data thus provide evidence for the spin-0 nature of the Higgs boson, with positive parity being strongly preferred.

 

The particle that they were testing was highly likely to be spin 0; it is further shown elsewhere that the particle is likely to be the Higgs

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.