Absolute Zero

[pulkit]

I know about the zero point energy, it is simply unavoidable. But, I believe absolute zero is something that can NEVER be achieved. It is a theoretical and practical limit to the temperature scale which can at best be approached assymptotically.

[Cap'n Refsmmat]

It is also a law that it cannot be reached. I forget which, but it is.

[pulkit]

2nd Law of Thermodynamics probably.....thats the one with loads of different statements

[5614]

i think so, cant remember, but its is definately impossible to reach absolute zero, however, one day we could get soooo close to it that we cant detect the difference between absolute and the temp. of the object, however, absolute itself is the boundary, it can be accessed or crossed.!

[swansont]

2nd Law of Thermodynamics probably.....thats the one with loads of different statements

 

The Third Law. You can't reach absolute zero by any finite process. (Nernst heat theorem)

[Ben_Phys618]

Still, its not a law derived from direct observation. I mean, we haven't observed that we CANNOT reach absolute zero. Sure, the heisenberg uncertainty principle, and the pauli exclusino principle SUGGESTS that it is impossible, but we simply may not have a requierd theory yet. Perhaps a theory will be proposed tha does for quatum mechanics what relativity did for Newtonian physics. I mean, before it was experimentally verified, people said einstein was wrong in saying that time would appear to slow down for an observer moving near the speed of light, that his equations musty be somehow wrong.

[pulkit]

The statement of third law I always knew was that "the absolute entropy of a perfect crystal at absolute zero is zero" .

 

Still, its not a law derived from direct observation. I mean, we haven't observed that we CANNOT reach absolute zero. Sure, the heisenberg uncertainty principle, and the pauli exclusino principle SUGGESTS that it is impossible, but we simply may not have a requierd theory yet. Perhaps a theory will be proposed tha does for quatum mechanics what relativity did for Newtonian physics. I mean, before it was experimentally verified, people said einstein was wrong in saying that time would appear to slow down for an observer moving near the speed of light, that his equations musty be somehow wrong.

I do think that this is highly unlikely because a lot of theories and laws would suggest that it is IMPOSSIBLE.

[swansont]

The statement of third law I always knew was that "the absolute entropy of a perfect crystal at absolute zero is zero" .

 

That's another way of saying it.

[SurfSciGuy]

These guys know a bit about low temperatures.

 

I would tend to agree with absolute zero being unreachable - you would need zero entropy, i.e. a perfect crystal which is impossible, of course you could try cooling a single atom - but you would need lots of atoms to do that. If you look at the experimental research, the energy cost is exponentially rising the closer researchers get to zero K.

[Ben_Phys618]

Hmmm......so maybe it becomes like the relativity equations, but in this instance, the closer you get to 0 k the more your research costs tend to infinity....We just need now to find a absolute zero analogy for tachyons (they are the inverse of normal particles, they go further away from the asymptotic value if they speed up, but can never drop below speed of light). So if we can find a way to create a particle already with a temp. below 0 k, then the research costs will drop exponetially the more we cool it into -k values....hmmmm