There's a mysterious threshold that's predicted to exist beyond the limits of what we can see. It's called the quantum-classical transition.
If scientists were to find it, they'd be able to solve one of the most baffling questions in physics: why is it that a soccer ball or a ballet dancer both obey the Newtonian laws while the subatomic particles they're made of behave according to quantum rules? Finding the bridge between the two could usher in a new era in physics.
We don't yet know how the transition from the quantum world to the classical one occurs, but a new experiment, detailed in Physical Review Letters , might give us the opportunity to learn more.
The experiment involves cooling a cloud of rubidium atoms to the point that they become virtually motionless. Theoretically, if a cloud of atoms becomes cold enough, the wave-like (quantum) nature of the individual atoms will start to expand and overlap with one another. It's sort of like circular ripples in a pond that, as they get bigger, merge to form one large ring. This phenomenon is more commonly known as a Bose-Einstein condensate, a state of matter in which subatomic particles are chilled to near absolute zero (0 Kelvin or −273.15° C) and coalesce into a single quantum object. That quantum object is so big (compared to the individual atoms) that it's almost macroscopic—in other words, it's encroaching on the classical world.
[Also Covered By]: http://arstechnica.com/science/2015/05/atomic-telescope-brings-atoms-to-standstill/
(Score: 2) by MichaelDavidCrawford on Saturday May 30 2015, @11:32PM
now it's important to understand that a theoretical model is not the same as an experimental demonstration. From time to time, experiment proves that theory is incorrect.
I don't recall his name but I could dig it up.
It is difficult to understand spin conceptually. The way I see it, spin is angular momentum but it is not rotation. If a charged particle has spin it also has a magnetic field.
The bound state of two or more particles is a single particle itself, it obeys all the same laws as elementary particles do but in a more complicated way.
This fellow modeled various numbers of particles trapped in potential wells, to observe what became of their spin. With many particles he of course found classical rotation.
I was going to explain what he found with a medium number of particles but it has been so long I cannot adequately explain it. I'll have to dig up his papers, perhaps his abstracts are online.
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