Date: 2/07/2018 18:32:46
From: transition
ID: 1247488
Subject: probing zero kelvin
what’s to be learned from this theoretical
right up there with contemplations about the singularity isn’t it?
what’s to be learned from this theoretical
right up there with contemplations about the singularity isn’t it?
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
I don’t think so.
The difference between vey big and infinite is infinite, but the difference between very small and zero is very small.
The Rev Dodgson said:
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
I don’t think so.
The difference between vey big and infinite is infinite, but the difference between very small and zero is very small.
Did you hear about the man who cooled to absolute zero?
he is OK now
The Rev Dodgson said:
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
I don’t think so.
The difference between vey big and infinite is infinite, but the difference between very small and zero is very small.
Not if you take the reciprocal.
Superconductors, superfluids, Bose-Einstein condensates, and all sorts of other weird and wonderful things happen as we zoom in on absolute zero.
There was a scientific american article many years ago about “temperatures below absolute zero, and how such temperatures can be considered hotter than infinity”. In that article, the temperature of a quantum system was defined as proportional to one divided by the energy gradient in that quantum system. As the energy gradient switches sign. One divided by the gradient, the temperature, switches from plus infinity to minus infinity. Minus infinity is a lot colder than absolute zero.
This only works in certain quantum systems, though. We don’t have to worry about temperatures below absolute zero in classical mechanics.
In comparison, singularities are exceedingly boring.
How close are scientists getting to absolute zero?
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
Have a look at this theory about what happens near absolute zero. Rather mind-blowing.
https://en.m.wikipedia.org/wiki/Absolute_zero#Thermodynamics_near_absolute_zero
mollwollfumble said:
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
Have a look at this theory about what happens near absolute zero. Rather mind-blowing.
https://en.m.wikipedia.org/wiki/Absolute_zero#Thermodynamics_near_absolute_zero
did go read that earlier after I posted, it’d be generous to say I half understood it.
still, my naive understanding inclines me to think something of the theoreticals of probing zero K is as interesting as the subject of the singularity, yet the former seems neglected, by contrast, of pop interest anyway.
mollwollfumble said:
The Rev Dodgson said:
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
I don’t think so.
The difference between vey big and infinite is infinite, but the difference between very small and zero is very small.
Not if you take the reciprocal.
Superconductors, superfluids, Bose-Einstein condensates, and all sorts of other weird and wonderful things happen as we zoom in on absolute zero.
Yes, as you zoom in, you can look at all these things without actually getting to absolute zero.
mollwollfumble said:
There was a scientific american article many years ago about “temperatures below absolute zero, and how such temperatures can be considered hotter than infinity”. In that article, the temperature of a quantum system was defined as proportional to one divided by the energy gradient in that quantum system. As the energy gradient switches sign. One divided by the gradient, the temperature, switches from plus infinity to minus infinity. Minus infinity is a lot colder than absolute zero.
This only works in certain quantum systems, though. We don’t have to worry about temperatures below absolute zero in classical mechanics.
Not very useful mathematical games by the sound of it.
mollwollfumble said:
In comparison, singularities are exceedingly boring.
Only because we have zero information about how a singularity would behave, if it actually existed.
mollwollfumble said:
The Rev Dodgson said:
transition said:
what’s to be learned from this theoreticalright up there with contemplations about the singularity isn’t it?
I don’t think so.
The difference between vey big and infinite is infinite, but the difference between very small and zero is very small.
Not if you take the reciprocal.
Superconductors, superfluids, Bose-Einstein condensates, and all sorts of other weird and wonderful things happen as we zoom in on absolute zero.
There was a scientific american article many years ago about “temperatures below absolute zero, and how such temperatures can be considered hotter than infinity”. In that article, the temperature of a quantum system was defined as proportional to one divided by the energy gradient in that quantum system. As the energy gradient switches sign. One divided by the gradient, the temperature, switches from plus infinity to minus infinity. Minus infinity is a lot colder than absolute zero.
This only works in certain quantum systems, though. We don’t have to worry about temperatures below absolute zero in classical mechanics.
In comparison, singularities are exceedingly boring.
How close are scientists getting to absolute zero?
At some point the return for effort must diminish for practical use though wouldn’t it.
https://www.livescience.com/25959-atoms-colder-than-absolute-zero.html from 2013.
> Atoms Reach Record Temperature, Colder than Absolute Zero. This unusual advance could lead to new engines that could technically be more than 100 percent efficient, and shed light on mysteries such as dark energy.
> With positive temperatures, atoms more likely occupy low-energy states than high-energy states, a pattern known as Boltzmann distribution in physics. When an object is heated, its atoms can reach higher energy levels. At absolute zero, atoms would occupy the lowest energy state. At an infinite temperature, atoms would occupy all energy states. Negative temperatures then are the opposite of positive temperatures — atoms more likely occupy high-energy states than low-energy states. The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved.
> objects with negative temperatures behave in very odd ways. For instance, energy typically flows from higher to lower temperature. However, energy will always flow from objects with negative temperature to ones with positive temperatures. In this sense, objects with negative temperatures are always hotter than ones with positive temperatures. Another odd consequence of negative temperatures has to do with entropy, which is a measure of how disorderly a system is. When objects with positive temperature release energy, they increase the entropy of things around them, making them behave more chaotically. However, when objects with negative temperatures release energy, they can actually absorb entropy.
> What’s the best way to cool something down? Stick it in the refrigerator, right? Well, this may work for a half-eaten sandwich, but scientists use laser beams, focused beams of light can cool a substance down.
> A vibrating aluminum membrane could be cooled to less than one-fifth of a single quantum, or packet of energy, lower than ordinarily predicted by quantum physics. The new technique theoretically could be used to cool objects to absolute zero, the temperature at which matter is devoid of nearly all energy and motion. The results were a complete surprise to experts in the field.
> The drum, 20 micrometers in diameter and 100 nanometers thick, is embedded in a superconducting circuit designed so that the drum motion influences the microwaves bouncing inside an electromagnetic cavity. Remarkably, this drum-like minuscule object was lowered to a temperature of 0.00036 Kelvin.
mollwollfumble said:
https://www.livescience.com/25959-atoms-colder-than-absolute-zero.html from 2013.> Atoms Reach Record Temperature, Colder than Absolute Zero. This unusual advance could lead to new engines that could technically be more than 100 percent efficient, and shed light on mysteries such as dark energy.
> With positive temperatures, atoms more likely occupy low-energy states than high-energy states, a pattern known as Boltzmann distribution in physics. When an object is heated, its atoms can reach higher energy levels. At absolute zero, atoms would occupy the lowest energy state. At an infinite temperature, atoms would occupy all energy states. Negative temperatures then are the opposite of positive temperatures — atoms more likely occupy high-energy states than low-energy states. The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved.
> objects with negative temperatures behave in very odd ways. For instance, energy typically flows from higher to lower temperature. However, energy will always flow from objects with negative temperature to ones with positive temperatures. In this sense, objects with negative temperatures are always hotter than ones with positive temperatures. Another odd consequence of negative temperatures has to do with entropy, which is a measure of how disorderly a system is. When objects with positive temperature release energy, they increase the entropy of things around them, making them behave more chaotically. However, when objects with negative temperatures release energy, they can actually absorb entropy.
> What’s the best way to cool something down? Stick it in the refrigerator, right? Well, this may work for a half-eaten sandwich, but scientists use laser beams, focused beams of light can cool a substance down.
> A vibrating aluminum membrane could be cooled to less than one-fifth of a single quantum, or packet of energy, lower than ordinarily predicted by quantum physics. The new technique theoretically could be used to cool objects to absolute zero, the temperature at which matter is devoid of nearly all energy and motion. The results were a complete surprise to experts in the field.
> The drum, 20 micrometers in diameter and 100 nanometers thick, is embedded in a superconducting circuit designed so that the drum motion influences the microwaves bouncing inside an electromagnetic cavity. Remarkably, this drum-like minuscule object was lowered to a temperature of 0.00036 Kelvin.
Can all objects/materials be cooled down to absolute zero ?
I imagine they’d break/shatter and how would radioactive material react
Cymek said:
Can all objects/materials be cooled down to absolute zero ?
I imagine they’d break/shatter and how would radioactive material react
Perfect crystals can, in theory.
Imperfect crystals may (or may not) have some strain energy that limits temperature.
I hadn’t thought of radioactive materials. I suppose that when they decay the kinetic energy of recoil (like the recoil of a gun) heats them up again.