Photon Matter

[Little Bang]

How many members believe that matter is somehow made out of electromagnetic energy?

[lemit]

As opposed to . . . ?

 

--lemit

[sanctus]

The question, does not seem to make sense to me...can you elaborate?

[Little Bang]

QM's standard model says the proton is made of quarks. It has no explanation for the mass of the electron. A collision between two beams of photons will produce an electron anti-electron pair.

[Qfwfq]

It has no explanation for the mass of the electron.

Why do you say this?

 

A collision between two beams of photons will produce an electron anti-electron pair.

Does this mean that photons are made of electrons and positrons?

 

Given that pair production can occur for any charged kind of fermion-antifermion, would you say photons are made of all these? Or would you say that these fields are coupled to the EM field because they carry charge? A similar thing goes for fermions that carry weak or strong nuclear charge and the associated bosons. We don't say that all these particles are "somehow made out of" each other, we just say it's got to do with how their interaction with each other works.

[Little Bang]

If Qm has an explanation for the mass of the electron please give that explanation in a form that any high school physics student can understand.

 

Does this mean that photons are made of electrons and positrons?

 

Brilliant question. No it means that all particles are made of photons

 

Another thought, the only phenomena in the Universe that can produce photons is the movement or acceleration of a charged particle?

[Erasmus00]

Brilliant question. No it means that all particles are made of photons

 

There is a problem with this- photons and electrons have different statistics.

 

What this means is that if you have a quantum mechanical wavefunction, and you switch two photons, nothing changes. We say photons are symmetric particles. If you switch two electrons, you get a negative sign. We say electrons are anti-symmetric.

 

In terms of physical effects- this means that electrons can never be in the same state (Pauli exclusion principle) and photons at low temperatures tend to clump into the same state.

 

But, most importantly- you cannot build anti-symmetric objects out of symmetric ones. So, you could try and build photons out of electrons (two anti-symmetric objects gives you a symmetric one), but you cannot build electrons out of photons (two symmetric objects are still symmetric).

[Little Bang]

So the Stanford linear accelerator experiment of 1997 was a hoax?

[Erasmus00]

So the Stanford linear accelerator experiment of 1997 was a hoax?

 

Pair producing fermions from photons is NOT the same thing as fermions being MADE of photons.

[Kharakov]

What this means is that if you have a quantum mechanical wavefunction, and you switch two photons, nothing changes. We say photons are symmetric particles. If you switch two electrons, you get a negative sign. We say electrons are anti-symmetric.

......

But, most importantly- you cannot build anti-symmetric objects out of symmetric ones. So, you could try and build photons out of electrons (two anti-symmetric objects gives you a symmetric one), but you cannot build electrons out of photons (two symmetric objects are still symmetric).

Photons could be antisymmetric with respect to time, such that photons either

 

1) photons are moving "forward" in time (emitted by the sun, for example, and absorbed by something here on earth)

 

2) photons move backwards in time (emitted by matter here on earth and joining an atom on the sun to split it into 2 atoms)....

 

Visitors .. can't edit thought now.

[freeztar]

How come the poll question asks a yes or no question and does not give yes or no as an answer? :)

[lemit]

How come the poll question asks a yes or no question and does not give yes or no as an answer? :)

 

d.

 

--lemit

[Qfwfq]

I hadn't noticed the poll answers!

 

If Qm has an explanation for the mass of the electron please give that explanation in a form that any high school physics student can understand.

AFAIK the Higgs mechanism explains all the particle masses.:)

 

No it means that all particles are made of photons

This is an arbitrary choice with no justification and the excellent point raised by Erasmus definitely casts a shade of doubt on it. Guess what, pair anihilation occurs too, it means the exact opposite of pair production. So, which is "made out of" which? Electric charge is the coupling between the fermionic and EM fields.

 

Photons could be antisymmetric with respect to time,

They are bosons. This means their state is symmetric for exchanges of pairs of them and it is strictly correlated to spin value being integer; fermions have half-integer spin value. It is not tied to time reversal symmetry.

[7DSUSYstrings]

QM's standard model says the proton is made of quarks. It has no explanation for the mass of the electron. A collision between two beams of photons will produce an electron anti-electron pair.

 

 

Have you ever considered the radial velocity of a light quantum? Think of the two beams, like chemicals in certain reactions, to have the presence of both chiral and non-chiral components. From either plane normal, they will have all the same apearance and rotational direction, but the mirrored particle will always seem to be rotating in the opposite direction, like two corkscrews (or perhaps DNA helice) intertwining. At synchronized velocities along the axes, the intertwining is coordinated with the rotational velocity, but if either axial or rotational velocity falls out of synch, the force particles collide and explode into two particles with different synchronizations and velocities.

 

An electron, or a quark or a photon of light all have different axial and radial velocities.

[Kharakov]

They are bosons. This means their state is symmetric for exchanges of pairs of them and it is strictly correlated to spin value being integer; fermions have half-integer spin value. It is not tied to time reversal symmetry.

 

I read (or saw) what appeared to be a reference to CPT symmetry in what Erasmus said (although he did mention spin statistics at the top of the very same post). And of course, before re-reading what he said to check to make sure I wasn't replying to one of my own thoughts (which it turns out, apparently I was), I ended up rushing off to greet my visitors... and posting what I think is an interesting (albeit unrelated) thought.

 

But enough justification for my mistake.

[CraigD]

Like previous posters, I can’t answer this poll’s question, because it doesn’t make sense to me. You can make massy particles such electrons and positrons (anti-electrons), and with more difficulty, composite one such a protons, neutrons, antiprotons and antineutrons, out of photons, and easily make photons by annihilating massy particles and antiparticles, but even though the statements are somewhat accurate and can lead to useful insights in physics and cosmology, it just doesn’t seem useful to me to say things like “particle/antiparticle pairs are made of photons split in half” or “photons are made of annihilated particle/antiparticle pairs”.

 

One statement I’ll jump on as clearly in need of correcting:

A collision between two beams of photons will produce an electron anti-electron pair.

2 photons can’t, in a strict sense, collide, or otherwise interact with one another in a way that affects either photon. On both a theoretical and practical level, this is an important concept.

 

You can demonstrate it pretty easily with a pair of laser pointers and whatever you have handy that can precisely point them (I’ve found most kinds of children’s or artist’s modeling clay serviceable for this), and either your naked eye, or if you need better proof, some sort of measuring device, such as a photoelectric light meter. Set up the two lasers so they intersect (standing up a paper target and placing each dot at the same place, then removing the paper, will do it), then observe what happens to the dot of one on a paper target when the other is removed or switched off: precisely nothing.

 

As noted above and in countless physics forums and textbooks, under correct circumstances, a photon can be changed into particle/antiparticle (eg: electron/positron) pair. They don’t, however, need to collide it with another to do this, nor is more than one photon needed.

 

In physics terms, photons' lack of interaction with one another is a manifestation of Bose–Einstein statistics, which describe boson such as photons. As the other fundamental bosons are effectively unobservable directly by everyday means, however, photons are the easiest bosons for demonstrations such as the above.

 

BE statistics can be contrasted with Fermi-Dirac statistics, which describe the other kind of particles that exist, femions (eg: electrons and positrons), which do interact with bosons. The paper target (or light meter) in the above demonstration interacted with the laser’s beam of photons because it contained electrons.

 

The practical consequence of this is that there’s no limit to the number of photons that can pass though the same small volume of vacuum (once you spoil the vacuum with fermions, all sorts of interactions can occur, though at most everyday beam intensities, anything with a refractive index close to 1, such as normal air, is much like pure vacuum). Were this not the case, simple high-quality lenses and telescope mirrors, which focus nearly all the light that strikes them into tiny focal points, would exhibit various troublesome effects. From time-to-time, computer engineers get excited by the prospect of passing data through tiny beam conduits at rates that would require thick arrays of even the most miniaturized electrical conductors, though so far such “photonic computing” remains largely in the realm of science fiction.

[Little Bang]

I have often wondered why they call it dogma, I think I understand.