[Pseudoscience-is-malarkey (OP)]

Our universe is full of limitations. There's a limit to how fast something can get, how much gravity a non-black hole object can have, etc.

[alancalverd]

Nothing can get colder than 0K - or indeed even approach absolute zero indefinitely.

If all the mass of the universe were invested in the energy of one electron it would have the highest achievable temperature.

[Bored chemist]

Nothing can get colder than 0K - or indeed even approach absolute zero indefinitely.

If all the mass of the universe were invested in the energy of one electron

...then there would be nothing to compare the election to. You wouldn't know it was moving. It would have zero energy from it's point of view, and there would be no other point of view.

If you took all the energy from the universe - apart from a few particles- then... you would have cooled those particles to absolute zero- which is impossible.

Temperature isn't a well defined concept if you don't have an ensemble of particles to consider.

If you got round all that- somehow- then you would still do better by giving all the energy available to a few neutrinos.

[alancalverd]

At the point where there were just two electrons left, each would have a definable kinetic energy. Now dematerialise one of them and impart all its energy to the other. It will experience acceleration and will therefore know it is the lastest and fastest! 

[Bored chemist]

At the point where there were just two electrons left, each would have a definable kinetic energy. Now dematerialise one of them and impart all its energy to the other. It will experience acceleration and will therefore know it is the lastest and fastest! 

Or it may realised that the magnitude of the acceleration could have been the same if it had slowed down to a stop.

[Petrochemicals]

Nothing can get colder than 0K - or indeed even approach absolute zero indefinitely.

What is absolute zero is it just a concept of vibration over time?

Surely the upper limit is light, no mass except relative mass, no way of higher speed, if light has a speed given that it is not entirely understood.

[Bored chemist]

What is absolute zero is it just a concept of vibration over time?

It's a temperature.
Specifically, it's -273.15C
On the other hand, "just a concept of vibration over time" is meaningless gibberish.

[alancalverd]

Carnot showed that the maximum efficiency of a theoretical heat engine (i.e. one that extracts heat from a hot source  and delivers it  to a cold source to produce mechanical work)  is

η = 1 - T_hot/T_cold

so for any finite temperatures, η ≤ 1 and there can only be one temperature T_cold for which η = 1, which defines absolute zero.

[yor_on]

That you can't get to zero kelvin is explained by the Heisenberg Uncertainty Principle. It just states that there always will be a uncertainty to the momentum which means that you can't get anything absolutely 'still', no matter how cold you try to make it. When it comes to how hot something can become I don't know any definition of it?

[chiralSPO]

That you can't get to zero kelvin is explained by the Heisenberg Uncertainty Principle. It just states that there always will be a uncertainty to the momentum which means that you can't get anything absolutely 'still', no matter how cold you try to make it. When it comes to how hot something can become I don't know any definition of it?

Not quite. The impossibility of reaching absolute zero can be established by purely classical thermodynamics.

The added complication from QM is this: even if a system were to be at absolute zero, it still has some non-zero amount of kinetic energy, the so-called "zero point energy." This is the minimum amount of internal energy the system can attain, so there is zero extractable energy, just not zero energy.

[chiralSPO]

If the "thing" still has to be recognizable as the "same thing" it started as, this will be highly thing-dependent. (ie there is a limit to how hot an ice sculpture can get, while still being an ice sculpture, and that is very different from the temperature at which protons cease being protons...

[yor_on]

Well, depends on definitions I think? HUP states that there is a uncertainty. It doesn't state that we have a way to measure it.

" Practically, the work needed to remove heat from a gas increases the colder you get, and an infinite amount of work would be needed to cool something to absolute zero. In quantum terms, you can blame Heisenberg’s uncertainty principle, which says the more precisely we know a particle’s speed, the less we know about its position, and vice versa. If you know your atoms are inside your experiment, there must be some uncertainty in their momentum keeping them above absolute zero – unless your experiment is the size of the whole universe. "


It's funny, in some ways it connects to light, doesn't it? The way we say that you will need a 'infinite energy' to reach 'c' for any matter related concept, and here the definition becomes that you need  a 'infinite amount of work' to reach 0 K.
=

You could argue that you don't need HUP but I wouldn't agree. Zero point energy is best exemplified by the Casimir effect
theorized 1948 but HUP, presented 1927, should be what it builds on, as a guess. I could look it up but I'm too tired for the moment.

[alancalverd]

The indeterminacy principle ("uncertainty" is a serious misunderstanding) does not predict or calculate absolute zero. It is an entirely classical thermodynamic concept.

What QM does predict is that helium, uniquely, would remain liquid at 0K and atmospheric pressure.   

[Bored chemist]

In quantum terms, you can blame Heisenberg’s uncertainty principle,

Not really.
If ( its a big "if") you cooled a crystal to absolute zero there wouldn't be a problem with the uncertainty  principle because, even at 0K the atoms would still be vibrating. If memory serves, the energy is half h f

Motion doesn't necessarily stop at 0K

[Petrochemicals]

That you can't get to zero kelvin is explained by the Heisenberg Uncertainty Principle. It just states that there always will be a uncertainty to the momentum which means that you can't get anything absolutely 'still', no matter how cold you try to make it. When it comes to how hot something can become I don't know any definition of it?

As stated earlier surely temperature is a measurement of particle movement over time, as such to achieve zero K, the said matter would have to have no energy ever in the existence of time, thus would have to have avoided the big bang. Idon't believe temperature is descrete and if it was you would need something of zero K to draw energy from other matter. If anything ever was zero K would it exist?

[alancalverd]

Whilst Heisenberg is often represented as the impossibility of knowing both position and momentum with absolute precision, that's a derivation from billiard-ball mechanics applied to bouncing a photon off a moving electron, which clearly cannot represent reality.

Consider a hydrogen atom. If the electron really is a moving particle it must be moving in some sort of orbit, because the atom has a finite size considerably larger than a proton. But an orbiting electron emits energy so it will spiral into the nucleus and disappear. Therefore the electron is not actually a moving particle and the classical model is false, even though it gives the right value for h.

Hence my preference for "indeterminacy" rather than uncertainty. Matter behaves as though  Δp.Δx ≥ h.

[yor_on]

BC that one you have to link. The way I understand it you can't reach 0 K. Are you suggesting there exist a possibility of it? Whether you want to call indeterminacy or uncertainty seems more of a personal taste to me Alan, I grew up calling it uncertainty and I will probably stay there :)

I don't know Petro, If we go by BC you seem to be able to, at least theoretically,  describe a state in where you can reach 0 K but where you still can't define the momentum, or lack of. What that implies would then be a state where you have to look for something complex, as in a imaginary number combined with a real, describing it. As it seems to me. That's why I want that link. Intuitively I would say that something should break down and change if you can reach zero Kelvin. But I don't know.

http://www.quantumphysicslady.org/glossary/heisenberg-uncertainty-principle-hup/
=

It depends on how you define heat possibly, and what you consider to be matter. Matter as waves or as something tangible that you can touch. If everything would be waves (matterwaves) then what HUP states should be that those waves aren't there, until we 'touch' them. And heat can be described through waves too. The absence of a wave jiggling / propagating would then be a state of absolute zero as I use to think of it, but if BC is correct, which he probably is :) you either can have a state of no jiggling / propagation still not able to prove it to be still, or you might be able to imagine that it becomes a doorway to another state.

Take a look at Jim Al-Khalili description in the link to see what I mean by HUP 'stating' that you need to 'touch' it. HUP becomes a very general application on almost everything it seems. Even waves doesn't come close enough, does it? Alan wants to call it indeterminacy and that seems correct in this case. A uncertainty of something implies that it exist, we just can't 'pinpoint' it until we touch it, where indeterminacy could be read as implying that it doesn't even need to be there at all. Which, to me then, connects to the idea of decoherence.

and what I mean by that is that you might be able to see the existence of something, once we 'pinpointed' it, as a result of a whole universe interacting. Or if you like the laws and properties existing defining it in your 'touch'. See why I find 'New Theories' a comfortable place?

[Bored chemist]

As stated earlier surely temperature is a measurement of particle movement over time, as such to achieve zero K, the said matter would have to have no energy ever in the existence of time,

Only to the same extent that an ice cube always had to be below 0C since the start of time.

[Bored chemist]

Are you suggesting there exist a possibility of it?

No
I'm pointing out that, even at very low temperatures the vibrational motion does not stop.
You can cool things down to temperatures like that- where you would expect few, if any  molecules to be vibrating. And they  don't stop. Low temperature heat capacities are another demonstration of the quantisation of energy.

Similarly, there's nothing in the uncertainty principle to stop you cooling a single molecule in a test tube down (The physicists' beloved ' particle in a box' model) to "zero".
The molecule would stop moving, but you wouldn't know where it was.
Translational energy doesn't have a "zero point energy" in the way that a vibration does.

Much as I love the Hitchhiker's guide to the galaxy, I'm not generally going to follow Alan's lead of using it as a source of scientific terminology.
" It is said, by the Guide, that such generators were often used to break the ice at parties by making all the molecules in the hostess's undergarments leap simultaneously one foot to the left, in accordance with the theory of indeterminacy."
https://hitchhikers.fandom.com/wiki/Infinite_Improbability_Drive

I will stick to calling things by the names that will ensure that they are recognised.

I agree the idea is badly understood but I'm not sure the name is the big sticking point.

[alancalverd]

It was Heisenberg's word.

The problem as I see it is that  the principle is usually taught via the classical photon/electron model, which leads to the absurd collapsing atom. I think the world has now grown up enough that we could teach physics from quantum mechanics and relativity, pointing out that as we scale up from  atoms and down from near-c velocities, we can make classical approximations, using continuum mathematics and invariant masses for most (but by no means all) engineering purposes.

The result would be a much clearer view of the current state of knowledge. But it requires, inter alia, abandoning the anthropic "uncertainty" business (and all the crap that goes with conscious observers...)  and accepting that there is an inherent indeterminacy at the root of the universe.