Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jan 20, 2017.
But that is exactly what I was thinking of when stating what you quoted in #40!
Log in or Sign up to hide all adverts.
No offense, but why are you appealing to him?
Why don't you appeal to a real scientist who works in the field... like Susskind for example, who teaches zero point fields in Stanford?
It doesn't offend me, but that highly qualified and highly capable gent would I'm sure be less than amused, and rightly so.
Stepping away from appeals to authority, recall why back in #25 I sided with Neumaier. You have yet to deal with the implications of L.Jaffe's analysis of Casimir force as %100 explainable by van der Walls interactions. Show me how ZPE 'vacuum fluctuations' can then have any room to exist - given the more popular treatments claim to show such also gives %100 the Casimir force. Both cannot be right. And van der Walls forces are for sure there.
I don't care if he won the Nobel peace prize, he doesn't qualify over a real physicist in the field. I consider Susskind a highly qualified and highly capable man in his own right; which is why I take him seriously when he teaches zero point fields in Stanford university. Use this man as your source of information, not someone who can make an elaborate argument.
And yet the same phenomenon cannot explain why a system never reaches zero kelvin, while fluctuations answers that naturally.
Nonsense. There is simply no way to exclude all thermal energy from a system. If there were, it would truly be at 0 degrees Kelvin regardless of ZPE fluctuations present. Which fluctuations are, as I stated earlier, simply a fact of existence in any matter system. No evidence whatsoever the vacuum itself possesses such. L.Jaffe's analysis very strongly implies ZPE vacuum fluctuations do not exist. Do the sum.
Thermal energy, is the presence of motion, motion comes from fluctuations. It isn't nonsense at all.
you speak about thermal energy as if it was something different, like it was an innate property of the vacuum without motion. Fluctuations provide that motion and therefore, the thermal energy you speak about. This is why we can define an equipartition theorem with thermodynamic energy, because the kinetic part explains the thermodynamic part.
And yes we have tried!!!
We have created plenty vacuums trying to squeeze every last bit of matter and energy out, but there always remains residual motion and therefore, a residual heat.
See e.g. 3rd para here: https://en.wikipedia.org/wiki/Zero-point_energy
ZPE in a matter system does not represent a finite temperature in any generally accepted sense. The distribution functions are entirely different for one thing.
Not really sure what you are getting at.
Zero point fields is by definition, the fluctuations of a ground state of a field. You can't freeze the ground state, it will always persist, no matter how much cooling energy you pump into the system.
Did you read this from the link you gave?
''Temperature arises from the intensity of random particle motion caused by kinetic energy (brownian motion). As temperature is reduced to absolute zero, it might be thought that all motion ceases and particles come completely to rest. In fact, however, kinetic energy is retained by particles even at the lowest possible temperature. The random motion corresponding to this zero-point energy never vanishes as a consequence of the uncertainty principle of quantum mechanics.''
This is basically what I have been talking about.
This explains only in a subtle way. It is much deeper, because fluctuations actually owe their existences to the uncertainty principle. This is why the random motion exists, because the uncertainty principle allows for these particles to exist, albeit, for very short timescales.
OK I will quote the relevant passage from that 3rd para in Wki link:
"The uncertainty principle requires every quantum mechanical system to have a fluctuating zero-point energy greater than the minimum of its classical potential well. This results in motion even at absolute zero. For example, liquid helium does not freeze under atmospheric pressure at any temperature because of its zero-point energy."
Notice that attaining absolute zero is consistent with a finite ZPE present. The latter is not thermal in nature hence does not contribute to temperature.
Needless to say, I disagree with that article's take on 'vacuum fluctuations', but that is beside the point here. And btw this answers your post #52.
If a general statement sure. But fails if applied to vacuum itself. Try dealing at last with implications of Jaffe's analysis of Casimir force. That link again: https://arxiv.org/abs/hep-th/0503158
It's worded not very well. Let me restate what it says:
The uncertainty principle allows for the existence of virtual particles to spontaneously be created at the fundamental level: This results in absolute zero motion. The absolute motion is still there when you remove all the physical matter and energy from space - an example of this is liquid helium which does not freeze under any atmospheric pressure because of the residual motion of the field.
There is no dispute over existence of ZPE motions in a matter system. Such does not constitute or contribute to, a finite temperature.
Now, it doesn't need to be motion of matter or energy present, you can remove all the matter and energy and spacetime will still not freeze over because of these virtual particles. It's not enough to say that matter or energy present in spacetime, has to move because of the uncertainty principle: because even if you remove all the visible matter and energy, you still find energy left. It's a simple, experimental truth that the vacuum will not freeze due to the Brownian motion of particles, or the zero point influence of the ground state fields.
That's not how I understand the physics. You can't actually talk about a temperature without invoking the motion of something within the system.
'spacetime freezing over'?! Sorry, such a notion I cannot argue about.Please Register or Log in to view the hidden image!
Please Register or Log in to view the hidden image!
Separate names with a comma.