# Schrödinger's cat explain color charge?

• Zachary Nichols
ThanksBillNo problem, I wasn't trying to imply that those principles aren't related. I was just trying to list some of the possible principles that could be involved in explaining a three state system.f

#### Zachary Nichols

I'm doing a science fair project involving trying to explain color charge with the principles behind the Schrödinger cat thought experiment; However I'm having trouble finding the right principle. Its math project was well. Can anyone push me into the right direction

What do you mean by "explaining color charge" and by "using the principles of Schrödinger's cat"? A priori, I do not see any obvious link. You need to describe better what it is you intend to accomplish.

What I mean is that the color charge of quarks are changing all the time and the quarks color charge states can be thought as to be in superposition with each other. I'm trying to explain this though the principles behind the Schrödinger thought experiment which includes quantum interfence, coherence, decoherence, entanglement, etc...

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I am not sure there is a direct link.

But a careful explanation of Scrodinger's cat may help.

Basically the solution to Scrodinger's cat is trivial in QM. The observation happened at the particle detector and everything is commom-sense classical from that point - the cat is alive or dead regardless of if you open the lid or not.

The purpose of the thought experiment was to explore an issue with the standard Copenhagen interpretation where QM, in that interpretation, and from the formalism anyway, its a theory about observations that appear in a common sense classical world. But that raises a couple of issues. First exactly where do we draw the line between quantum and classical - in practice, like the Schodinger's cat thought experiment, its trivial to determine where it is (its obviously at the detector) but precisely how do you define it? This is related to an analysis of measurement done by Von Neumann in his classic Mathematical Foundations of QM where he showed the cut really could be placed pretty much anywhere - even though in practice its never an issue. The second problem is how does a theory that assumes the existence of a classical world explain it?

A lot of progress has been made in resolving that:
http://motls.blogspot.com.au/2011/05/copenhagen-interpretation-of-quantum.html

Because of that I am not sure there is a link to colour charge.

Thanks
Bill

Ok that makes since however to better explain what I'm trying to do. I'm try to see if principles like quantum interfence, quantum decoherence, quantum entanglement, and quantum coherence plue other principles can explain the three state system of color charges. What it boils down to is can you describe a three state system with those principles

Ok that makes since however to better explain what I'm trying to do. I'm try to see if principles like quantum interfence, quantum decoherence, quantum entanglement, and quantum coherence plue other principles can explain the three state system of color charges. What it boils down to is can you describe a three state system with those principles

I doubt it.

Those principles are from standard QM and colour charge etc requires QFT. They are usually used in the measurement problem, quantum computing etc etc - not QFT. Although my knowledge of QFT isn't as good as I would like it I haven't seen it anywhere in that field.

Thanks
Bill

Ok then however excluding the color charges can you describe three state systems with those principle's if not how would you do it

Ok then however excluding the color charges can you describe three state systems with those principle's if not how would you do it

I wouldn't attempt to - its the domain of QFT which is devilishly difficult (and I don't know its application to colour charge) - but the Wikipedia article may help:
http://en.wikipedia.org/wiki/Color_charge

If however you wish to join me and go down the road to a proper understanding of QFT I have the following book and its very good (it also accessable after a basic course on QM or reading Susskinds QM book):
https://www.amazon.com/dp/019969933X/?tag=pfamazon01-20
https://www.amazon.com/gp/product/0465036678/?tag=pfamazon01-20

Not all things are directly related in QM.

Thanks
Bill

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Sure you can describe a three state system with ordinary quantum mechanics. Depending on the system, you may invoke decoherence, if that is appropriate.

I can define a system that may be in state |a>, |b> or |c> and do the usual things you can do with quantum mechanics. No QFT required. You also wouldn't necessarily need to invoke schrodingers cat, decoherence or whatever either. I'm not sure what the point of that would be for this project, but there are plenty of interesting three level systems out there. The classic three level laser system that every undergrad studies would be a good example.

However, any as bhobba rightly points out, colour charge is the domain of QFT. Or more accurately, QCD.

You can motivate the requirement for colour charge fairly easily though - just consider the elementary particle Δ++, which is made up of three up quarks. Clearly, without colour charge, you would violate the pauli exclusion principle - three up particles would all have the same spin. Thus, the quarks need to be different by some quantum number, thus the introduction of "colour charge".

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If you want to present cool quantum phenomena in three-level systems, I suggest you have a look at electromagnetically induced transparency (EIT) and velocity selective coherent population trapping (VSCPT). (Unfortunately, there seems to be less information about the latter outside scholarly publications.)

OK I only chose color charges because it was a three state system and i couldn't find another one. Thank for the feed back also can you give me any other three state system I could describe