Is spinon a cofined neutrino?

[Duda Jarek]

Recent experiments

http://www.nature.com/nphys/journal/v2/n6/abs/nphys316.html

confirmed theoretical results that electrons are not undividable as it was believed -for some conditions it's more energetically preferable for them to separate their charge part (called holon or chargon) and its spin part (spinon).

I think it's a good time to discuss about these results and their consequences.

 

Thinking about 'pure spin' (spinon) made me associate it with low energy electron neutrino, especially that I imagine particle's properties which can only occur in some integer multiplicities like charge or spin as topological singularities - such separation greatly connects the whole picture.

Another argument is for example muon(tau) decay - it looks that e.g. there has been spontaneously created neutrino-antineutrino pair (electron) and the spin part of the muon(tau) was exchanged with the one with smaller energy and so more stable.

 

The other question is about statistics of these (quasi?)particles.

For me statistics is the result of spin - so spinons should be clearly fermions ...

 

What do you think about it?

[swansont]

The electron is not divided into charge and spin — the "quasiparticle" term refers to a collective behavior of electron and its surroundings that's being investigated.

[Duda Jarek]

From the abstract of the paper: "The spinon and holon branches are found to have energy scales of approx 0.43 and 1.3 eV".

Spinons and holons undergo "separation into collective modes" ... but to behave in separate modes, doesn't they have to separate themselves?

Imagine a string in a harmonic mode ... now it separates into two modes/strings ... doesn't it mean that that it's atoms also separates?

Ok - these amplitudes can be extremely small so they stay 'in one particle' ... but behave separately.

 

Neutrino is 'a pure (electron) spin' ... and so is the spinal part of electron ...

They energetically prefer to stay together (modifying their structure a bit), but 'pure spin' has unchangeable quantum number (spin) and has extremely small energy - doesn't have what to decay - should be stable (neutrino).

'Pure charge' (holon) interacts much stronger, have larger energy - should quickly 'catch' neutrino (spontaneously created in pair) - should have very small half life time.

And we have Majorana hypothesis - there are only two types of electron neutrinos ... adding the charge we have four possibilities as in Dirac's equations ...

Edited August 11, 2009 by Duda Jarek

[swansont]

This is condensed matter physics — it's collective behavior of the electron and its surroundings (i.e. in a wire) that is being treated as a quasi-particle. This is not describing a bare electron.

[Duda Jarek]

From http://www.lbl.gov/Science-Articles/Archive/ALS-spinons-holons.html:

In this technique, x-rays are flashed on a sample causing electrons to be emitted through the photoelectric effect. Measuring the kinetic energy of emitted electrons and the angles at which they are ejected identifies their velocity and scattering rates. This in turn yields a detailed picture of the electron energy spectrum. Ordinarily, the removal of an electron from a crystal creates a hole, a vacant positively-charged energy space. This hole carries information on both the spin and the charge, as observed in a single peak of an ARPES spectrum. If spin-charge separation occurs, the hole decays into a spinon and a holon and two peaks in the ARPES spectrum are observed.

and there is a nice graph with two distinct peaks ...

[swansont]

Yes, and … ?

 

"the hole decays into a spinon and a holon"

 

The hole. i.e. the quasiparticle, which is a description of the absence of an electron, displays this behavior. Not the free electron.

[Duda Jarek]

The important is that their spin and charge parts are connected, but can behave separately - it strongly suggests that the fundamental blocks building our physics are the carriers of indivisible properties like charge or spin.

Sometimes they create pairs to reduce energy and finally particles are stable when they are in the state of the lowest possible energy, like neutrino or electron.

And strong argument that this spin part is just a neutrino is muon decay

muon -> electron + electron antineutrino + muon neutrino

isn't that just exchange of the spin part to get the lowest energy and so the stable state?

[swansont]

The important is that their spin and charge parts are connected, but can behave separately - it strongly suggests that the fundamental blocks building our physics are the carriers of indivisible properties like charge or spin.

Sometimes they create pairs to reduce energy and finally particles are stable when they are in the state of the lowest possible energy, like neutrino or electron.

And strong argument that this spin part is just a neutrino is muon decay

muon -> electron + electron antineutrino + muon neutrino

isn't that just exchange of the spin part to get the lowest energy and so the stable state?

 

This behavior is seen ONLY in a collective system. There is nothing "fundamental" (as used in this context) about it.

[ajb]

My understanding is that in metals the Femi liquid model of electrons is applicable. That is the charge and spin carriers are almost non-interacting quasi-particles. These quasi-particles are bare electrons "dressed" with virtual electron-hole pair excitations. This increases the mass of the electrons slightly.

 

The important thing here is that the quasi-particles carry the same charge and spin as the electron.

 

However, the same is not true in 1-dimensional systems. In particular, the spin and charge can propagate independently, in the form of collective excitation modes called "spinons" (neutral spin excitations) and "holons" (spinless charge excitations).

 

As swanson has said, this is collective behaviour found in condensed matter physics. It is possible something similar can be found in particle physics (maybe something in quark-matter?).