Science a GoGo's Home Page Forums General Discussion Physics Forum Mass & Velocity

So lets bring in another piece of the puzzle in our discussion which is Quantum Spin.

So we have these virtual particles and we have the concept of spin but the virtual particles actually spinning in the classic ball or earth rotation sense. The unequivocal answer is yes and there are a number of lines of proof. This can catch even physicists out in that they may not imagine that something that is not quite classical can behave in a classic way you may want to look at the exchange between Lubos Motl and Aidan Randle-Conde it is worth a read (http://motls.blogspot.com.au/2012/12/the-electron-is-spinning-after-all.html)

Lubos correctly identifies the facts about electron and proton spin first define what classic spin is defined as



Now identify a way to test it classically



There are more technical physical tests but the above should easily convince anyone that the spin is real and classical.
So can something that is not quite classical spin classically. Well actually we have a number of common things you will be familar with that will help.

First lets consider a tornado or water eddy they spin and they are not solid and real but are spins of the medium they are in. Now they require a medium or ether and we have concluded that spacetime has none so they are interesting but not useful.

Next lets consider the swirling magnetic field in an induction motor



So now we have a spinning field across an area of spacetime and spacetime itself isn't spinning so we are getting closer. If you place something magnetic inside the swirling magnetic field in an induction motor it will follow it around so our thing that isn't at all solid or real called a field can be measured and has effects in our classic world even though what exactly the swirling field is remains a bit puzzling.

Bill S the above may help you with your thinking about whether a field is inside or outside spacetime but I am going to leave that up to you to work through

Hopefully by now we have got you to realise that non classical things can indeed give rise to classical measurements and that is where confusion starts.

If you try and make the electron solid and real and spin it around like a solid earth model your calculations go crazy because the elctron is not classical in it's nature at all but it's spin is measurable in a classic way.

Now lets bring in our negative temperature below absolute zero and tie it all together.

The problem with temperature is it a classical measurement and that measurement started off historically by a column of liquid expanded inside a glass tube, I am sure we all know what a thermometer is.

The problem is it is not a singular measurement of a singular property although classic physics assigned it to the concept of the vibration momentum of matter it is a simplification that is not actually real. Under quantum mechanics temperature is simply a statistic made up of mathematics of momentum and a number of quantum spins.

Conceptually it easy to show what happens and why classic physics gets it so wrong, I will introduce couples world.

Imagine you live in couples world where you may only enter where you are a male and female couple and in general male and female couples always move around together lovingly holding hands.

If you were an observer measuring in couples world you would make an interesting observation that no matter where you measure in couples world one always finds on average one testicle and one developed breast per person in couples world.
As our couples move around that statistic would be born out to be true and you may even conceed it is a classic measurement in couples world.

There is however a problem even in couples world when our couple go to the toilet they seperate and our scientists happens to take up camp outside the male toilet. What he notices is a violation of couple land law there are almost no developed breasts entering the male toilet so he would call it negative breast. Similarly he goes over to the female toilet and he notices he has negative testicles.

What they are doing in the negative temperature work is playing with quantum mechanics to do something weird in a classical sense. The actual physical real spacetime can not have a negative temperature it is forbidden because it is a bound state construct we know that because thats how we derived the concept of temperature and discovered it in the first place. It is vitual you realize that spacetime itself COULD NEVER have a negative temperature it is truely a couples world.

What they are really showing off is that fact and they created the cubicles for the toilets via QM to seperate our couples in couples world and measure negative temperature. The negative temperature can only exist in there QM toilet cubicles they created and can never exist in couples world

So it's a cool experiment in the sense that it yet again underlines QM is correctly predicting weird things that classic physics would never realise and it may be experimentally useful to probe quantum effects but it has no real relevance to our real world and our real world can never go below absolute zero.

That will do for now lets see how you go.