# Can an atom reach a temperature below absolute zero?

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I have done quite a bit of research on this, and my friend and I are at a disagreement. As we physically cannot get a particle to absolute zero, as that would require us to get every particle in the universe to absolute zero, I am asking whether this could be theoretically possible.

Here is what I currently know: Temperature is the measure of heat (obviously), which is the measure of the speed that particles have (these are basics that I didn't need to research at all). The particles therefore would have to have negative speed. But, as I thought about it, the speed of particles would tell how much energy they have. Energy is linked to the electrons. So, a solid, liquid, and gas all have electrons, but not plasma, as it is the form of matter that can have no electrons. If, hypothetically, some molecule of plasma came in contact with some antimatter in the plasma state, the protons would be attracted to the antiprotons, as they have opposing charges. The outcome would be a molecule with absolutely no energy, or possibly negative energy. I don't know if this could physically work, as it would be pretty much impossible to create this experiment, as we could not make antimatter into plasma with current technology. I would like to know if this experiment could even possibly work, or if it can't, why it wouldn't work.

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Energy is linked to the electrons.

Not sure where you get that from. Temperature is a measure of the kinetic energy of the atoms. That depends largely on the nucleus as the mass of the electrons is insignificant.

So, a solid, liquid, and gas all have electrons, but not plasma, as it is the form of matter that can have no electrons.

Plasma normally (always?) has electrons, just dissociated from the atoms.

the protons would be attracted to the antiprotons, as they have opposing charges. The outcome would be a molecule with absolutely no energy, or possibly negative energy.

The outcome would be a burst of gamma radiation as they annihilated one another.

as we could not make antimatter into plasma with current technology

Actually, that is the easy bit (for hydrogen nuclei, anyway). The tricky bit is getting the anti-protons to combine with anti-electrons to make anti-atoms. And then containing the (uncharged) anti-atoms. See the CERN Alpha experiment for more info.

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The outcome would be a molecule with absolutely no energy, or possibly negative energy.

That's simply not true.

Annihilation of proton-antiproton paths are listed below:

Total energy prior annihilation is equal total energy after annihilation.

I don't know if this could physically work, as it would be pretty much impossible to create this experiment, as we could not make antimatter into plasma with current technology. I would like to know if this experiment could even possibly work, or if it can't, why it wouldn't work.

Antimatter (antiprotons) are in plasma state when we're creating them in particle accelerators. They don't have positrons (yet).

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Negative temperature is possible in some systems, but these are actually very hot — they have a lot of energy.

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