PeterDonis said:
Off topic, but do you have a reference for this? At true absolute zero, it isn't just the motions of atoms and molecules that are "frozen" (within the limits of the uncertainty principle)--the motions of *all* particles, including nuclei, protons, and electrons, are "frozen" too. The recent breakthroughs on creating super-cold states like the Bose-Einstein condensate are examples of such states, but their temperatures are still above absolute zero (even if only by a zillionth of a degree). There are negative temperatures in physics, but they aren't colder than absolute zero; they're hotter than positive infinity.
Well one, I have a degree in chemistry, so I've read about this and specifically asked my professors about it.
Two, here's a quote from Ask Science Theatre: "Temperature is a physical quantity which gives us an idea of how hot or cold an object is. The temperature of an object depends on how fast the atoms and
molecules which make up the object can shake, or oscillate. As an object is cooled, the oscillations of its atoms and molecules slow down. For example, as water cools, the slowing oscillations of the molecules allow the water to freeze into ice. In all materials, a point is eventually reached at which all oscillations are the slowest they can possibly be. The temperature which corresponds to this point is called absolute zero. Note that the oscillations never come to a complete stop, even at absolute zero."
Three, from Wikipedia.com encyclopedia: "For the case of free atoms at temperatures approaching absolute zero, most of the energy is in the form of translational motion and the temperature can be measured in terms of the speed of this motion, with slower speeds corresponding to lower temperatures. In fact because of quantum mechanical effects, the speed at absolute zero is not precisely zero, but depends, as does the energy, on the size of space within which the atom is confined. At absolute zero the molecules and atoms in a system are all in the ground state (i.e. the lowest possible energy state) and the system has the least possible amount of kinetic energy allowed by the laws of physics. This minimum energy corresponds to the zero-point energy encountered in the quantum mechanical particle in a box problem. As mentioned above, the lowest possible energy is not necessarily zero energy, due to the ramifications of quantum theory." (Later in this cite it talks about BEC being near-AZ, the negative temperature/hotter than infinity bit).
The above doesn't mention the movement of quarks and electrons (other than electrons being in their lowest ground state) ... so those subatomic particles are still moving in some way (for example, even in their lowest energy state, electrons are still moving at the speed of light), thus, energy. Theoretically, you could extract that energy (though in the real world we don't know how to do that) and thus make that material "colder," even if it's at absolute zero, but not in a sense meaningful to the use of the word "temperature."
