Does “spin” imply physical rotation?

I would prefer "internal" rather than "intrinsic. Rather than denying rotation, it's better to say it's internal, meaning "ignorable" except as provided through external physical effects like angular momentum and magnetic moment. David Hestines has an interesting mathematical development of plausible internal structure for an electron in "The Zitterbewegung Interpretation of Quantum Mechanics" in Found. Physics., Vol. 20, No. 10, (1990) 1213{1232. Whether such effects are "ignorable" or not depends on your interests, evidently.

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Deleted profile

James!!! its internal as well but I just wanted to say that spin is the inherited property of fundamental particles. But in classical macro Physics, we can have several objects that they are spinning and that is the complete rotation and not intrinsic property. So in quantum realm if we define the spin is the intrinsic property.

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18th Dec, 2014

James Langworthy

The thing we use the word "spin" to describe is the experimental finding that an atomic electron has 2 possible energies. This, the first use of this word historically, has proved to be ubiquitous for any QM fermion, both elementary and composite. The word has to be treated as QM technicalese: that is its meaning is in the math.

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18th Dec, 2014

James Langworthy

Well if you want temporal precedence, you have the history of how it came to be. But QM isn't causal. In Feynmann's sum over possible trajectories you take into account those both before and after the event. And in elementary QM the wave function can only predict probabilities. My point is once a new observation has been shown to work in the math, you don't need (or want) the history, you just do the math.

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Deleted profile

Yes Classical world is a reality but in a macroscopic form There are now quarks and gluons of matter already discovered. It means the reality is hidden inside. To know that hidden reality the quantum mechanics was developed where the classical laws completely breakdown and behave quite differently.

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Deleted profile

You should read [1] it is a very interesting approach based on Belinfante's calculation [2]

Kind regards,

[1] Ohanian, H. "What is spin?" Am. J. Phys. 54, 500 (1986); [2] Belinfante FJ "On the spin angular momentum of mesons". Physica 6: 887 (1939)

http://scitation.aip.org/content/aapt/journal/ajp/54/6/10.1119/1.14580

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18th Dec, 2014

James Langworthy

My point in citing the Hestenes article above is that he does see an interpretation of internal rotation due to spin. But to get there he developed the math from the Dirac equation. It's a natural development in gamma matrix algebra. But not 3D rotation, rather 4D.

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19th Dec, 2014

Vikram Zaveri

Independent Researcher, Mumbai, India

In my attached published article I have shown that the curvature of the electron orbit in hydrogen atom draws on certain amount of kinetic and potential energies affecting the momentum of the electron and the spin-orbit interaction energy constitutes a part of this energy. The theory presented in this article is not a perturbation theory. Dirac's theory cannot detect this curvature effect because spin in that theory is not a part of the dynamics of motion but it gets introduced as a perturbation just like Darwin and Pauli theory. Also the selection of the radial momentum operator is somewhat arbitrary in Dirac's theory and not Hermitian as pointed out by several authors. The spin in my published article is associated with the physical angular momentum and is part of the Laplacian operator eventhough comment following eq.(2.4) in published article states that the spin corresponds to intrinsic angular momentum of the point particle. This happened because the referee did not accept my original submission, the unedited excerpt from which is attached below (RG QA). See eq.(2.4) and comments following. Looking at this the referee provided following comments.

(b) Introduction of the spin operator in equation (2..4) i.e. S=m_s vxr is incorrect as spin is though a space-time object but for a point particle it can not be defined in terms of velocity and radial distance. It corresponds to intrinsic angular momentum of the point particle. Introduction of the spin dependent mass is also ad hoc.

In reponse to this referee comment, I was compelled to change eq.(2.4) and comments following, otherwise my paper would not have been published.

Article Quarkonium and hydrogen spectra with spin-dependent relativi...

RG QA
.pdf
84.26 KB

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19th Dec, 2014

James Langworthy

In Hestenes development spin arises in an isolated electron.

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19th Dec, 2014

Richard Gauthier

Santa Rosa Junior College

Dirac claimed in his Nobel acceptance speech that the electron moves at light speed but with a very small vibrational amplitude, so that only a sub-luminal electron velocity can be observed. Hestenes found from the Dirac equation a light-speed charge moving in a helical path with a radius of that same amplitude hbar/2mc . I recently proposed (https://www.researchgate.net/publication/267922850_The_Electron_Is_a_Charged_Photon ) that Dirac's light-speed electron and Hestenes' light-speed electric charge (Zitter model of electron) are actually a charged photon that circulates helically and models a moving electron consistent with the relativistic energy-momentum equation for the electron. And now I have discovered that the charged photon model generates the relativistic de Broglie wavelength h/(gamma mv) from the longitudinal component of the wave vector k of the charged photon moving along its helical trajectory. Since the Schrodinger and Dirac equations for an electron are based on the de Broglie wavelength, this will lead to a new interpretation of quantum mechanics based on the charged photon model.

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19th Dec, 2014

James Langworthy

The usual meaning of causal is that the effect succeeds the cause. In this sense classical is causal but QM is not. This is internal to the theory. One still requires empirical input and as I illustrated by the history of spin, the math is informed by the necessity to agree with experiment. I think you speak of cause in a metaphysical way as being an extenal requirement on the theory. In QM one means something different by agreement with expeiment than for classical physics. In elementary QM, one doesn't calculate a "pysical result" like is done in classical. Instead you calculate an expectation value. So here agreement means statistical agreement in a large numbers of trials. You might think the same thing happens in a real classical experiment but in classical the statistics is an adjunct. In QM it's built in.

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19th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

The problem actually starts with the concept of rotation, even in Galilean Geometry. It is defined only for rigid solid, is physically represented by a vector, assimilated (because the Lie agebra of SO(3) is three dimensional) with a vector of space, and is different from the phsysical phneomenon (one cannot observe the geometric rotation of a symmetric body, but one can measure it through its inertial rotational momentum). In relativist geometry it gets worse. There is no rigid body. The Lie algebra of SO(3,1) is six dimensional, and its measure (through the well known formula) involves the spatial speed. And in the common Poincaré's group the motion of a material body is represented by 10 parameters. Even by using the usual rule of thumb to take c to infinity, one cannot get back the 6 parameters which obviously define the motion of a material body in usual Physics. So we have to conceive all this differently.

The usal explanations of QM assume either something that we cannot understand (what is the job of scientists ?) or a mix of classical physics (electric currents in a rigid body) as in Hestesnes solution.

Acutally the solution lies with spinors, which have proven to be efficient to explain the motion of a particle. But we have to be fully consistent, and assume that a spinor represents the full motion (translation and rotation) of a body, whatever the scale. This is not a revolution, Clifford algebras (from where spinors come) are routinely used to represent motions in softwares. Then the spinor represents not only the motion, but the full momentum, translational and rotational, and it is not too difficult to prove that the motion itself can be represented with 6 parameters, with clear meaning. And the "spin", with its binary value, is just due to the fact that, for any observer, the rotation can be measured along the trajectory or along the opposite.

So, to be short, spin is anunavoidable consequence of relativist geometry.

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20th Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

The answer on the thread’s question is, rather probably, “yes”. But if one uses the term “physical” correctly.

To begin with note, that everything in our Universe and outside is/ are some informational patterns – that is rigorously proven (see http://viXra.org/abs/1402.0173)

From this follows rather reasonable suggestion that every material particle/body and Matter in the Universe is some automata that operate under a few number of logical rules, which realize itself in physics as “Nature laws”.

Next reasonable suggestion – all elementary particles are built by some template, when every particle is a closed loop algorithm; which, quite naturally, is implemented on a “hardware” of some fundamental logical elements (FLE). The FLEs are some informational patterns also, but that is the next level, which can be not known on this level of the consideration.

There are a lot of reason to suggest (for example - C. F. Weizsäcker;s idea that our space is 3D since Matter’s basic logical elements (“Urs”) are binary), that the FLEs are binary elements that can “flip” adjacent FLE in the 4D dense lattice of FLE; and every element has 4 (8), 3 spatial an 1 temporal, independent degrees of freedom to flip and to flip next corresponding FLE.

So every particle in the 4D Euclidian spacetime is a 4D circle, where through the circle a “flipping point” constantly runs; the radius of the circle is the Compton length of the particle, the angular momentum is equal to Dirac’s constant h with the bar.

So every particle should have the spin be equal to1; what is true for photons – at motion of a photon the flipping point moves along some 4D helix having radius be equal to the photon’s wave length; the 3D projection of the helix is observed as 3D EM wave.

As well as all “massive” particles, which are created by temporally directed momentums, move along time axis with (if are at rest in the space; it seems that is practically true for particles (atoms, objects, etc) that are at rest on Earth and so on) the speed of light and with the angular momentum be equal to 1.

But massive particles differ from photons. There is only one temporal dimension in the spacetime and so photons, which move in the space only, have only one helix. But the space is 3D, and so a particle’s helix of spatially flipping FLEs having the “flipping plane” be orthogonal to the t-axis has, also, this plane be orthogonal to some spatial direction, and so the particle should have a second – a “spatial” angular momentum, which is equal to 1 also.

It seems that by some unknown now way these two “spins” realize themselves as one “spatial spin” =1/2 in Matter.

Nonetheless here aren’t problems as, e.g., “rigid body problem”, etc.

More – see “The Informational Conception and Basic Physics”, http://arxiv.org/abs/0707.4657

Cheers

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20th Dec, 2014

Otto E. Rossler

University of Tuebingen

I once described an exophysical interpretation where spin is caused by microtime reversals, with Michael Conrad, in a book.

But it is very hard to generate confidence into that Everett-related picture.

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21st Dec, 2014

Kimmo Rouvari

N/A

"Therefore, do you believe that fundamental particles have a physical angular momentum that is currently not understood?"

Absolutely! My own pet theory is based on the hypothesis and so far it's doing great.

Book Introduction to Theory of Everything by Illusion

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21st Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To Sanjay,

Saying that a spinor is a solution of the relativist Dirac equation does not tell us what is a spinor. The Dirac's equation is no more than an identity, on which we have made the magic of "usual quantic substitution of variables", and then assumed that the syymbols are matrices. OK, the computation works (only in special relativity) but if this is the only answer which prevails, it would be more honest (and simpler) to tell that spinors are a formalism that we use efficiently in our computation, and nobody know what they mean.

For how long physicists will have to live with this narrative ? As the quote :

"No one fully understands spinors. Their algebra is formally understood but their general significance is mysterious. In some sense they describe the "square root" of geometry and, just as understanding the square root of -1 took centuries, the same might be true of spinors" (Michael Atiyah)

But the time goes, and the time limit is coming !

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22nd Dec, 2014

Michael Lashkevich

Russian Academy of Sciences

What do you mean, when you say `physical rotation'? Strictly speaking, this term is only well-defined for nonrelativistic absolutely solid bodies. If you say that you mean `movement of particles with nonzero orbital momentum', then the answer is NOT (at least in the framework of the standard quantum field theory). The matter is that the total angular momentum is a sum of two parts: orbital momentum ($\vec L=\sum\vec r_i\times\vec p_i$ as an operator identity) and spin ($\vec S=\sum\vec s_i$). This sum is an integral of motion (it commutes with the Hamiltonian) and conserves, but neither spin nor orbital momentum conserves by itself.

Do not blame me for speaking about theory. Both orbital momentum and spin can only be defined in a framework of a theory. They are not purely experimental quantities. The very measuring of these quantities refers to a theory. The total angular momentum, in contrast, is more experimental quantity, since it (more precisely, its change) can be measured by using its only property of conservancy, independently of theoretical details.

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22nd Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

Again (see the SS post above) here is no necessity to consider “absolutely solid bodies”, the elementary particles aren’t “bodies” and don’t “rotate”.

These particles simply are some cyclic algorithms (that’s the experimental fact: they have – an least the stable ones – constant properties. But, at that, they constantly change their internal states and therefore constantly move along the [coordinate] time axis in the Matter’s spacetime. This cyclic (helix) motion in the spacetime isn’t a helix motion of some particle’s “center of mass”, that is the motion of “flipping point” of the algorithm, which, as it seems has the size be equal to the Plank length – in any “time moment” the particle has this size, but its properties are contained in the next flipping FLE parameters of flipping.

And – relating to something as “…Both orbital momentum and spin can only be defined in a framework of a theory…” – jean claude above is right – such a statements aren’t true principally. Any physical theory and any mathematics, if applied in a theory, doesn’t create any new information – all information is contained in the theory in its postulates (in a system of axioms for given mathematics) already. Real development of any theory occurs only if a new postulate appears; and for this is necessary, first of all, to understand better existent postulates.

An example – near 100 years the rather strange postulate that “in any reference frame the speed of light is constant” worked in the theory that well explained/described/ solved a lot of concrete physical problems. Though, in fact, this postulate declared rather strange idea that there is a magic particle “photon” (light firstly), which forces the space and the time in the spacetime “to unite” and, further, “to contract”, “to dilate”, etc. What is a nonsense, of course; and so there is evident necessity to modify the theory principally.

As well as there is the necessity to principally modify the QM – including through clearing of “physical sense” of postulating in the QM basic notions – including – of the spin.

In other case the existent situation – already near 40 years nothing new appeared in physics, though thousands of mainstream physical journals publish a huge number of papers that consider/ solve in fact nothing more then some textbooks’ tasks, will conserve.

More – see the Net link in the SS post above.

Cheers

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22nd Dec, 2014

Michael Lashkevich

Russian Academy of Sciences

Sorry, Sergey. I understand, what is `movement in space' or, in other words, world line in spacetime, but I cannot understand what could mean `movement in spacetime'.

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22nd Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

-? Any change of every material object, for example of a particle, is a logical transition, which is a step in logical system – the 4D FLE lattice in the [real] absolute 4D Euclidian spacetime.

At that there are two rules/possibilities - “times” that govern the particle’s motion in the FLE lattice (in the spacetime as “possibilities”), - “true time” and “coordinate time”; the last establishes that this’s time step – along “time axis” in the spacetime – happens (or, more correctly, “the coordinate time interval is spent”) if only a change of internal state of the particle happens.

(“True time step” happens (or, more correctly, “the true time interval is spent”) always – at a change of internal state and at a change of particle’s position in the 3D space; the true time is not a coordinate in the spacetime.)

So all/every material object/particle always move in the spacetime with identical 4-speed – the speed of light.

The Minkowski (as well as pseudo Riemannian, though) spacetime isn’t real, it is a mathematical technique that are useful sometimes, but in this spacetime the 4-speeds of all material objects are identical (the seed of light if c=1) also; and, for example if you draw on Minkowski diagram the world line of a particle at rest, you draw a line that is parallel to t-axis, not a dot.

Again – see “The Informational Conception and Basic Physics”, http://arxiv.org/abs/0707.4657 ; it is desirebale to read http://viXra.org/abs/1402.0173 ,

http://vixra.org/abs/1409.0031 , http://viXra.org/abs/1311.0190 also.

Cheers

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23rd Dec, 2014

V. Fulcoli

Sapienza University of Rome

@John Macken :

is strange because instead of doing one lap around him to see it the same way, you have to make two turns around, and so it is like a t-shirt: when you take it away not from the head but from the belly (to understand) you find her "smersata" (ie turned + turned = ^2) and to flip it over, you have to put it back in a standard way for two times. Thus the spin pertains to the space of the particle seen as a membrane.

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23rd Dec, 2014

Stefano Quattrini

Ordine degli ingegneri della provincia di Ancona

@Synay

"In other words, perhaps there is no need to worry about the actual nature of spin. It doesn't really matter whether there is an actual rotation of the electron that accounts for it."

That any rotation in a "classical sense" occurs should be excluded. What is not maybe the case to exclude is the effect on the space-time of such "eigen-motion".

Spin has the dimension of h, an angular momentum, which is an ACTION. This quantity is fundamental in dynamics since everyting in physics is regulated by the least action principle (and maximum entropy, so far).

Spin is strictly connected to ZPE and to the De Broglie frequency, it is the direct consequence of the HIGGS mechanism which is responsible of the mass of these half spin particles (PENROSE).

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23rd Dec, 2014

Raul Simon

L A M B

All I can say is that, when you study angular momentum in QM, you end up with a bunch of formulae (matrices, etc.), and the physical meaning is lost from sight. As Sergey says, postulates (hopefully not counterintuitive) are badly needed in QM.

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23rd Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To V.Fucoli

The strange thing about having to turn two times with a spin is nothing more than to say that the right group to consider with rotations is the spin group. The spin group is the group of rotations plus the scalars 1 and -1. When you speak about a rotation, it is equivalent to take the opposite axis and the opposite rotational speed, but this is physically not equivalent, when you have to define continuously the axis and the speed along a path (as we should do) : then we need to distinguish both, and this is just what the spin group do. Penrose gives a tour about that witha belt.

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23rd Dec, 2014

V. Fulcoli

Sapienza University of Rome

@jean claude Dutailly

why half-integer spin particles obey Fermi-Dirac whilst integer ones Bose-Einstein? what it means, having in mind the description of spin, the fact that the matter can or can not condensate, permeating and penetrating in the same space? I think that an adequate description of the concept of spin should at least clarify this aspect, not only using an appropriate use of mathematical commutator, but i cant see it

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23rd Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To V.Fucoli,

My remark was general about the definition of rotations : the right group to consider is the Spin group, for logical and physical reasons. The Spin group is formally defined from Clifford algebras, which are a key element in Spinors.

The distinction between half integer and integer spin comes from the labels of different representations of the groups Spin(3) and SO(3). As to why we have the Dirac's statistic, this is a long, nebulous, story, that I leave to the priests in QM, because I am not a believer. Sorry.

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23rd Dec, 2014

V. Fulcoli

Sapienza University of Rome

@jean claude Dutailly

I cant see the spin... i know how to represent it, but still cant see.

And to me it is smtg related to Daniel Kovach post... it is only Knowledge... and semantic about representation of....

p.s.

I like to see at QM as a for a reduced/inned system

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23rd Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To V.Fulcoli

The question is complicated because it involves several diffrent things.

1. The way we represent the kinematics of material bodies : the usual moment p=mv and rotational moment fails when we are in the relativist context, for several reasons. So one needs to use another formalism, which the spinors. The spin up or down is in fact simple, when one refers to what I noticed in the previous post : there are two ways to define a rotation according to the orientation of the axis, and up or down is related to the orientation along the spatial speed or the opposite.

2. Common QM. This is a mix of formal procedures for computation and physical assumptions. This is muddled and the introduction of the spin and spinor is less than convincing, but I leave this to people of the faith.

3. QM proper and its axioms (Hilbert space, eigen values,...) is not a physical theory (the axioms do not mention any single physical object ). QM is not a theory about how the world works,, it is a theory about how it seems (how it is represented). All the axioms can be mathematically proven from the way physicists build their models (see my paper on this site). Another approach is from the information theory. From my point of view it is more abstract and complicated but basicallyit starts from the same premices.

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23rd Dec, 2014

Michael Peck

John,

The answer is both yes and no depending on what you mean by "physical rotation". Many early attempts at giving a classical origin to spin was through introducing circular currents of charge density. In essence, this can be viewed as the electron following a circular path in space so that it creates a magnetic dipole moment. The only problem however is that the value predicted by this method is half of the observed magnetic dipole. Thus in this interpretation the "physical rotation" cannot be a correct.

What others and I (independently) have done is shown that the rotation can be attributed to the particles field (i.e. the electric field). So lets start off with the magnetic field produced by a traveling electric field at a point in space.

B = 1/c2(v x E)

If we assume that the electric field is rotating on an axis at the speed of light (at each point of the field) then the magnetic field becomes,

B = keq/(cr2) φ'

Plugging the zitterbewegung radius into the second equation and using the definition of dipole moment, we get the correct value,

uB = qeh_bar/2me

You can think of QED and QFT as producing more exact calculations in these regards, i.e. by applying a physical rotor to the fields. In general, these foundations begin to emerge at the Dirac equation (in fact, mass in the Dirac equation is directly related to spin, but it fails to provide any insight into the physical essence of mass).

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23rd Dec, 2014

V. Fulcoli

Sapienza University of Rome

@Michael Peck

U are right ... to me it is clear that the shift button that swaps massive-massless particles is a distortion of the space... indeed the Maxwell's equation for the massless wave could be fitted into the Klein-Gordon's, ie to that one with a mass, just if the equations are related by a covariant derivative instead of a normal one.... where the symbols of christoffel are related to mass ... have to do with

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23rd Dec, 2014

Michael Peck

Fulcoli,

Yes, applying covariant derivatives to either the Dirac equation or Klein-Gordon will allow introduction of the classical electromagnetic field. Any solution to the Klein-Gordon EQ will in addition be a solution to the Dirac equation. The simplest form that includes gravity and EM would be Du = ∂u + (1/4)wuabηab - (ie/hc)Au where wuab is the spin connection.

However, I don't completely agree with how the standard model is formulated (it is very ad-hoc and fine-tunable after a point, although it fulfills its purpose as a theory that can predict the outcome of measurable quantities in most cases). For example, the Higgs field and boson do not explain the physical essence of mass, it simply gives it to certain particles. To arrive at a final theory, it is likely that most of the classical fields and macroscopic properties will need to be abandoned in return for an emergent theory at the Planck-scale.

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24th Dec, 2014

Stefano Quattrini

Ordine degli ingegneri della provincia di Ancona

Peck,

"For example, the Higgs field and boson do not explain the physical essence of mass, it simply gives it to certain particles. "

The physical essence of mass is something emerging by resonance with the Higgs field, and is the essence of the phase/charge too, because mass and charge come out together. Maybe the Planck scale will confirm such mechanism.

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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

About mass,

Mass is both an inertial characteristic and the charge of the gravitational field, and their identity is well checked experimentally. I do not see how the standard model, as well as the common QM, which ignore gravitation, can give an adequate representation of mass. The Higgs mechanism has been introduced to give mass to some bosons (which are, whatever is said somewhat special particles) and to fermions because some fermions disappear in the lagrangian because of the use of the Dirac's operator (in a specific formalisation of spinors). Whence the need for the patch given by the Higgs mechanism, which raises more questions (it should be associated to a fifth force, where does it comes from ?) than it gives answers. But the sad fact is that billions of euros have been invested in one unique model (the standard model, born around 1973, more than 40 years ago) and there are too many interests at stake to admit that it's time for a change. Would you buy a computer designed in 1973 ?

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24th Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

Yea, by some rather strange reasons in many papers, scientific and not too scientific, now one can meet declarations that “Standard Model with Higss mechanism explains the mass notion”;

though any normal physicist understands – if a theory doesn’t contain some explanation of the gravitational mass notion and the equivalence of masses, then this theory adds, rather probably, nothing new in the clearing of the mass problem.

Though a corresponding model exists from 2007 (the last formulation – “The informational model – gravity”http://vixra.org/abs/1409.0031 ) already; as well as from 2007 there exists the suggestion - how to test the model (“The informational model - possible tests” http://arxiv.org/abs/0706.3979) by measuring a randomness of gravity force acting on a monochromatic light beam.

At that the experiment can be made now – there exist already the light sources having necessary stability, and interferometers having necessary sensitivity; for example – there can be any existent interferometer for discovering gravitational waves.

What is necessary – to add the 3-th interferometer’s arm having length 300 – 400 m that is orthogonal (say, in a well) to existent two [horizontal] arms. Moreover, since it is necessary to have horizontal arm (one it’s enough, though may be useful to have the second horizontal arm for a monitoring) having length 300 – 400 m also; thus any technique that was built in first gravity waves experiments can be used, for example – TAMA installation.

So such an experiment evidently will not require $billions and can be prepared and made in a couple of years…

Cheers

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24th Dec, 2014

Eric Lord

Indian Institute of Science

Total angular momentum (orbital + spin) is conserved. Orbital angular momentum is a consequence of rotation, but that doesn’t necessarily imply that spin is. The answer seems to lie deeper. Poincaré Gauge Theories are extensions of General Relativity that abandon Einstein’s assumption that the affine connection is symmetric. The skewsymmetric part of the connection is “torsion”. In this framework the coupling of matter to curvature and torsion is analogous to its coupling to the electromagnetic field (and other gauge fields) – through the covariant derivative. Energy-momentum density is the source of curvature (as in Einstein’s theory) and spin density is the source of torsion - analogous to the way charge density is the source of the electromagnetic field. (Spin and charge also have in common that, for a single particle, they are quantized.) Torsion is associated with rotation in the sense that “parallel transport” in a spacetime with torsion has a rotational component. This might possibly have some relevance to the question “Does spin imply physical rotation”...

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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

Eric,

Einstein-Cartan models have a historical interest. Nowadays General Relativity can be fully represented with fiber bundles. It is actually simpler, and one does not have all the hassle of metrics computations. Moreover it works with any kind of principal connections and we are no longer stuck with the Lévy-Civita, symmetric, connection. Tthe scalar curvature can even be computed with any principal connection. This requies just the use of tetrads, which is a well known method.

But the issue of the representation of motion of material body stays. With a look of the matrix of a change of gauge in Special Relativty one can see that the 4 dimensional rotation involves the spatial speed (the boost) so this is more complicated than in Galilean Geometry. The use of the group of displacements (the Poincaré's group) is wrong : spatial speed appears two times. So one cannot transpose what is done in Galilean Geometry (translation + rotation = displacement) in the relativist context. We need a new tool, to represent the kinematic characteristics of mterial bodies, and this tool is the spinor, which involves Clifford algebra. Then the introduction of the Spin group is clear and the common spin up or down has a simple explanation (the scalars +1 and -1 belong to the spin group).

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24th Dec, 2014

Eric Lord

Indian Institute of Science

Jean Claude ~

I agree - the fiber bundle method is very elegant. Attached: my humble contribution to it. But I'm old-fashioned. I'm happier with the older ways (-:

https://www.researchgate.net/profile/Eric_Lord3/publications?sorting=newest&page=4

https://www.researchgate.net/profile/Eric_Lord3/publications?pubType=inProceedings&ev=prf_pubs_inp

50
.pdf
358.67 KB

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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To Eric,

I did not want to be pedantic. I am an old hand, but very new in Research, so I had to learn from the youngs !

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24th Dec, 2014

Stefano Quattrini

Ordine degli ingegneri della provincia di Ancona

Jean Claude, I fully agree

We need a new tool, to represent the kinematic characteristics of mterial bodies, and this tool is the spinor, which involves Clifford algebra.

We have to use spinors (quaternions) instead of tensors in order to describe GRT and extend it..

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24th Dec, 2014

Anatolij K. Prykarpatski

Cracow University of Technology

Yet..., nobody ... knows what is the spin...It is important, that we understand, more or less, how it works, not understanding well why!...

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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

Sorry Anatolij,

The purpose of Science is to help us to understand, and not only to learn computing methods. Scientists are paid by the tax payers for this job. If scientists contend themselves with efficient softwares, we can replace them by computer people, this would be cheaper.

Anyway by toiling with the same concepts that nobody understands, there has not been much more needed progress since 50 years. We need more efficient nuclear reactors, but we do not know anything more about weak and strong interactions than in 1945. It would be nice to master gravity (after all this is a very weak force)...But we have new mysteries. Science is not answering a mystery by a riddle.

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24th Dec, 2014

Anatolij K. Prykarpatski

Cracow University of Technology

Jean claude Dutailly@

Yes, Jean, I meant the same you claimed - and it was exactly why it is so irritating me and all others...

Regards!

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24th Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

... When rather many things become be more udersnandable in framework of the informational model as a result of circular FLE flipping point movement;

including the spin (for the photon directly), at that there is no necessaty, e.g., for the electron, to think about “solid body rotation”, as well as as a “point charge” rotation;

the mass as inertia – since the moving flip-point is a gyroscope that has an axis and a frequency, so to change them is necessary to impact the gyroscope by non-zero momentum; since in macrophysics only a spatial impacts are possible, that relates in – in the frequency increase for photons (that move in space only) and – since spatial impact never is directed along the particle’s 4D momentum (the gyroscope ‘saxis direction) the particle’s inertia (the mass) changes between “transverse” and “longitudinal” masses; when the identity of transverse and “relativistic” masses is direct consequence of that t-axis in the “Cartesian” 4D spacetime is orthohonal to any spatial line, including the x,y,z, axes;

the gravitational mass, this force weakness (comparing with, e.g., the EM one), the equivalence of the gravity and the inertia;

the identity of one kind particles, as some clones of same algorithm;

etc.

With grundings that all physics acts in absolute 4D spacetime – so the relativity theory with the pceudospaces isn’t totally adequate to the reality.

So it seems as rather useful to fill up the model by corresponding mathematics and so to make a theory from it.

Though before it would be very useful to make the pair of basic experiments – (1)- to measure absolute speed of some space probe and so – of practically anything in Sun system; and (2) – to measure the randomness of the gravity force...

Cheers

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24th Dec, 2014

Michael Peck

Stefano,

What I meant by physical essence of mass is that if it emerges from the Higgs field, what is such field beyond a few symbols on a piece of paper? I do agree that ½ spin, mass and charge are intimately related, as all charged particles have mass (down to the quark level).

An example from my own work; mass and charge arise from a scalar field that is the result of contracting a Planck-scale metric (not to be confused with the macroscopic space-time metric). The idea is that space at the Planck-scale behaves like a 3d spring-mass system. After tensor contraction you should have a field in the form of E = sqrt(m^2 + p^2), where m and p provide the classical values at the classical position. Since the proper equation squares the scalar field it is possible to have negative and positive “mass”; however, the effect will always produce normal attractive gravity due to the squaring of m. Thus mass in this framework can be thought of as a physically real disturbance at the Planck-scale that would be similar to moving a positive or negative Ricci scalar through space (at the classical position of a particle). Of course, particle charge will have the same sign as scalar "mass".

Obviously this is an emergent theory at the Planck-scale. One would simply find the proper solutions, configure the 3d spring-mass system and then let it evolve. Accordingly, such evolution should produce all classical forces (gravity, electrodynamics, electroweak, ect) from a single (unified) field. I've only been able to connect electrodynamics and general relativity so far.

Theory of ever
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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

Actually one can introduce spinors, spin, chirality, antiparticles, all together in the GR context, without any assumption about a Higgs field, additional dimension or other physical assumptions. This is just a matter of maths and a good understanding of Clifford algebras. For those who can be interested they can have a look at my paper about particles and fields on this site. I am working on an improved version, the ideas are the same but I hope it will go a bit further and will be easier to understand.

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24th Dec, 2014

Raul Simon

L A M B

I am still curious about how spinors can enter General Relativity. Eddington worked on that, and I have read all his harder books, but I still don't see how to connect GR and ,say, the Dirac equation...

Sorry that I am still not answering your questions...

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24th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To Raul

Because there is no need to use the Dirac's equation. If you look at the usual demonstration you see three steps : i) an identity ii) a substitution of symbols iii) an interpretation of symbols. This is not at all a demonstration, perhaps a genial intuition, but nothing more.

To tell it in simple words.

i) Take a perfectly symmetric spinning ball. By definition there is no way to measure its rotation (no point to follow). But anyway the rotation has an impact, as any golfer knows. So geometric and kinetic rotations are not the same thing.

ii) The problem comes from the fact that physicists have been lazzy and define rotation using rotating frames, because this is the way mathematicians do. So we have the Poincarré's group which, since Wigner, is the basis for the definition of bosons, fermions....

We have to consider the kinematics property of a particle (a material body without perceptible internal structure) as an intrinsic property of the body. In the fiber bundle formalism this is simple : in a gauge attached to the particle, this is a constant vector, in a gauge of an observer this is a quantity which changes with the gauge of the observer. So thie spinor is an element of an associated vector bundle, associated to the principal bundle in which the gauge of the observer is defined. And this is as easy in GR than in SR. Even more illuminating.

A point which is not understood, is that in GR motion is absolute (a point on a manifold is unique, and the velocity, the derivative with respect to the proper time, is an intrinsic vector which does not depend on a basis). It is the same for the spinor : it sums up the inertial characteristic of the particle (mass and moment of inertia) and its motion (rotation and translation), and it is measured differently in different bases, depending on the choice of gauge, the change following the rules imposed by the gauge group (the Spin group) : this makes it a geometric quantity, because of its measure, not because of its nature. So there is no need for any physical assumption, just some maths, and be sensible.

This is also an illustration of the fact that QM is not a physical theory : this is not a theory about how the world works, but about how it looks (that is how we represent it)

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2 Recommendations

25th Dec, 2014

Richard Gauthier

Santa Rosa Junior College

The charged-photon model of the electron includes physical rotation in its spin, based on Hestenes' analysis of the relativistic Dirac equation. The model has just be shown to predict the electron's de Broglie wavelength at https://www.researchgate.net/publication/269932279_The_Charged-Photon_Model_of_the_Electron_the_de_Broglie_Wavelength_and_a_New_Interpretation_of_Quantum_Mechanics

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25th Dec, 2014

Stefano Quattrini

Ordine degli ingegneri della provincia di Ancona

Yes...

I would add that if we express everything with Quaternions it is more likely to match them with the Maxwell equations too, originally written with such complex numbers.

The singularites of the field can be treated with Cauchy-Rieman integrals and residuals as well and quaternion holomorfic functions are defined.

Instead of the Riemann two dimensional surface of the complex logarithm

function, we get the four dimensional manifold..

Very interesting in the paper attached.

http://arxiv.org/abs/math/0209166

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25th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To Stefano,

The starting point is the Clifford algebra Cl(R,3,1) or Cl(R,1,3) (depending on the signature of the metric, they are not isomorphic). A spinor is a vector of a vector space E such that (E,g) it is a representation of the Clifford algebra (g stands for gamma matrices). The problem is that Cl(R,3,1) representation is on 4x4 real matrices (the Majorana spinors) and Cl(r,1,3) is on 2x2 quaternionic matrices. So we must make a choice of signature. But knowing (from the standard model) that spinors are on complex vector spaces, the best solution is to look for a representation through the Clifford algebra Cl(C,4), which is on 4x4 complex matrices. So we keep the real algebras, which are isomorphic to subalgebras of Cl(C,4) and we have a representation in complex vector spaces and we are not obliged to make a choiceof signature at once .There is a final trick, to reduce a bit the set of spinors. Eventually we are left with an inertial part, with mass (positive or negative depending on particles / antiparticles), 3 parameters for the inertial moment (as usual), a 3 vector for rotation, and 3 vector for translation, all together bunched in a single spinor which transforms adequately with the spin group. And this is valid at any scale. One can use it to study the pattern of the orbits of a star system, as well as the usual measure of the spin in a Stern Gerlach experiment.

To tell that this is not too fancy, the paper has been rejected by arXiv. Probably because it has no string attached, or is not enough multiversed. But a first version is available on serious sites such that this one. I am working at improving it.

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25th Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

A little too emotional, but in substance – true...

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25th Dec, 2014

jean claude Dutailly

International Laboratory of Contemporary Physics

To Manuel and Sergey,

Actually there is no equation involved. I define spinors according to a mathematical, rigorous and consistent formalism, without any physical assumption, it stands on its own. There is nothing like a cause / effect assertion.

Then one can confront this formalism with physical phenomena that it can represent. It fits, and is efficient or not. Of course the construct hast been made with this need in mind. And this is satisfying that a spinor is defined by all the parameters known and used by physicists. The wrapping is just different to be easy to use with QM and RG.

This is absolutely similar to what you do when you represent a position by coordinates, speed by derivatives and expressed as a vector : you have on one hand a mathematical formalism, which must be consistent with the rules of mathematics, and on the other hand physical phenomena that you try to represent. The big problems start when people believe that reality is their equation.

This is different from what some say that mass is due to some field, or that spinors are solutions of the Dirac equations. I do not tell anything about how the wold works, I just try to find a nice way to depict it in order to better understand how it works. The painting should be consistent (mathematically), efficient (easy to compute with), and give a clear idea of how the things work. The problem is when you have mathematical tools which, from the very beginning, .are deemed impossible to understand. Then don't expect to get a good picture !

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25th Dec, 2014

Sergey Shevchenko

Institute of Physics of the National Academy of Science of Ukraine

Dear jean claude,

what you write is, in many aspects, correct. But with at least two remarks:

(1) - the mathematics must relate to some experimental situation and could be experimentally tested, and,

(2) – the initial postulates/ suggestions must be logically consistent.

And these conditions must work both simultaneously, in other case some “theories”, as, for example – the SR – can appear; where evidently logically inconsistent postulate that all inertial reference frames are equivalent is posited; thus (Dingle’s problem) both observers, if they move relatively, must – if the SR is true – believe that vis-a-vis’s “time dilated” relating to him; what is evident logical nonsense. At that -, if they check the vis-a-vis’s time rate experimentally, they will obtain the same absurd result. Further the postulat was used as the ground to declare rather strange suggestion that real spacetime is pceudoeuclidian, with imaginary time or space; etc.

Or, one can remember 2011 epopee, when near hundred papaers in arXiv and mainstream journals “theoretically grounded” evident experimental artefact – since the SR allows superluminal motion – of the “superluminal neutrino”; though it is clear, that any superluminal motion isn’t possible; and even if it is possible, then, since all material objects always are simultaneously in the same [true] time moment, then if some superluminal particle was born in a material object (the target), then it escapes from Matter and cannot hit in any other material object (the detector)...

Cheers

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25th Dec, 2014

Raul Simon

L A M B

This indeed a fascinating discussion. Thank you to you all, especially to Jean-Claude, Charles and Richard. Personally, I think I am too old to learn the fiber-bundle formalism (even if it is at all necessary, which I doubt).

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