Have scientists ever taken matter down to absolute zero degrees?

Question

If not, how do they know it will stop all atomic activity in a clump of matter?

Answer 1

They cannot reach as per

Answer 2

Reaching absolute zero is against the third law of thermodynamics. Absolute zero is the point at which particles have a minimum energy (not zero energy and there is still some activity), determined by quantum mechanical effects, which is called the zero-point energy.

The lowest temperatures that have been achieved are on the order of a picokelvin (10^−12 K). These are spin temperatures of nuclei which are out of equilibrium with the lattice vibrations and electrons of a solid. The lowest temperatures to which the electrons have been cooled are on the order of 10 microkelvins in metallic systems.

The theory states that at absolute zero lattice and atomic vibrations cease.

Answer 3

No, they never have.

The whole point of zero kelvin is that it represents absolute zero, the point at which all activity stops. It's not a calculated point in temperature, it's a definition.

Absolute zero = no activity.

From there, scientists calculated what temperature absolute zero would be relative to celcius.

So, FIRST they said what it was in theory, THEN they said where it would be on a thermometer. Does that make sense?

Answer 4

No, but they've gotten extremely close to absolute 0. The understanding of what will happen at absolute 0 comes from the theories of energy and the relationship between energy and temperature.

Answer 5

No, a good way to think of temperature is to think of it as the inverse of dS/DE, the change in entropy per change in energy. Zero temp would mean the S vs E curve would be vertical, which isn't possible. Infinite temperature in a system is possible if the S vs E curve is flat. Negative temperatures are possible if adding energy reduces entropy (negative temperatures are hotter than positive ones, because their inverse is less--big negative temps are just barely hotter than big positive temps--small negative temps are very, very, very hot). But I can't think how to set up zero temp.