Below I've linked a video from PBS Space Time, which is a really nice science channel and usually presents very well researched and narrated videos. In this video, though, one thing got me confused - the video is about absolute zero and at one point when the presenter is talking about Bose-Einstein condensates he says this: "There's only one substance is known to produce superfluid for conditions possible in the lab. And that substance is helium. In particular, helium-4. Helium-4 has a total spin of 0 which makes it a boson...".

This is confusing to me. Can we really talk about an atom as if it were an elementary particle?

 

https://youtu.be/OvgZqGxF3eo?t=3m57s

Edited December 11, 20178 yr by pavelcherepan

A boson is not necessarily an elementary particle.
It is a particle ( or compound particle ) which obeys Bose-Einstein statistics.
Similarily, a fermion obeys Fermi-Dirac statistics.
( hence the names )

Ya, something odd happens when things become superfluidic, they have zero viscosity which is kinda like how a Superconductor has zero resistance which is not actually zero just very close to zero, I did this experiment during college where you run AC current through YBCO a high temperature superconductor and there is still resistance in the form of impedance to some degree which can be measured as near zero but not actually zero, I imagine super-fluids are like that too near zero not zero actually for viscosity.

Superfluid Properties video

 

 

 

Edited December 11, 20178 yr by Vmedvil

1 hour ago, MigL said:

A boson is not necessarily an elementary particle.
It is a particle ( or compound particle ) which obeys Bose-Einstein statistics.

Thanks. I was not aware of this. Now it makes much more sense.