Colder than Absolute Zero?

  • kew1

    Posts: 1595

    Jan 04, 2013 11:36 AM GMT
    http://news.discovery.com/earth/record-temperature-set-colder-than-absolute-zero-130104.html

  • Lincsbear

    Posts: 2605

    Jan 04, 2013 3:39 PM GMT
    The far reaches of physical research are certainly moving in some pretty exotic realms!
    For example, the universe is thought to be ninety percent 'dark' matter ie non-baryonic(protons and neutrons)!
    And there`s this 'dark' energy, too, a weak, anti-gravitational force operating only at the scales of intergalactic distances, or cluster and superclusters to accelerate the expansion of the universe!
    It`s beginning to look like the universe is 'open' ie infinitely expanding.
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    Jan 04, 2013 3:48 PM GMT
    Very interesting, thank you for sharing!
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    Jan 04, 2013 3:51 PM GMT
    Its hard to imagine the sensation of this negative temperature. At least earlier it was simpler to understand the zero kelvin- the COLDEST temperature. Don't know what to make out of this negative temperature.

    From the article
    Oddly, another way to look at these negative temperatures is to consider them hotter than infinity, researchers added.

    To comprehend the negative temperatures scientists have now devised, one might think of temperature as existing on a scale that is actually a loop, not linear. Positive temperatures make up one part of the loop, while negative temperatures make up the other part. When temperatures go either below zero or above infinity on the positive region of this scale, they end up in negative territory.


    If they are hotter than infinity doesn't that mean they are towards the higher scale. Why is it called as COLDER than absolute zero?
    Won't it be better to call it as HOTTER than infinite temperature. Its just the behavior of atoms has changed. From the article it seems its combination of both. COLDER than absolute but HOTTER than the infinite temperature. What a weird phenomena!
  • spacemagic

    Posts: 520

    Jan 04, 2013 4:10 PM GMT
    This made my brain hurt, but in a cool way.
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    Jan 04, 2013 4:22 PM GMT
    [quote][cite]Shagglot said

    If they are hotter than infinity doesn't that mean they are towards the higher scale. Why is it called as COLDER than absolute zero?
    Won't it be better to call it as HOTTER than infinite temperature. Its just the behavior of atoms has changed. From the article it seems its combination of both. COLDER than absolute but HOTTER than the infinite temperature. What a weird phenomena![/quote]

    The definition of "hot" versus "cold" really has to do with how likely something is to give up energy. The more likely, the hotter it is. That's the deal with negative temperatures .... Those objects REALLY want to give up energy!

    The idea of a negative temperature is kind of odd, and only really is defined based on what I said above. You're not supposed to be able to cool something down to zero and then make it negative, but you can put something into a negative temperature state, and the article describes a state as such:
    "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."

    It looks to me that the researchers manipulated their system so that more high-energy states were occupied than low ones, thus achieving the negative temperature state.
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    Jan 04, 2013 4:26 PM GMT
    Curiouser and curiouser... I wish a link to the actual published findings was included.
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    Jan 04, 2013 4:26 PM GMT
    LeapHigher said

    The definition of "hot" versus "cold" really has to do with how likely something is to give up energy. The more likely, the hotter it is. That's the deal with negative temperatures .... Those objects REALLY want to give up energy!

    The idea of a negative temperature is kind of odd, and only really is defined based on what I said above. You're not supposed to be able to cool something down to zero and then make it negative, but you can put something into a negative temperature state, and the article describes a state as such:
    "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."

    It looks to me that the researchers manipulated their system so that more high-energy states were occupied than low ones, thus achieving the negative temperature state.

    Hmm!! That makes sense.
  • Lunastar

    Posts: 328

    Jan 04, 2013 4:29 PM GMT
    spacemagic saidThis made my brain hurt, but in a cool way.


    I see what you did there icon_cool.gif
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    Jan 04, 2013 4:33 PM GMT
    I hate absolute zero... I get hard.. then someone comes and breaks my heart
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    Jan 04, 2013 4:35 PM GMT
    Can't be colder than my bedroom.
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    Jan 04, 2013 4:39 PM GMT
    LeapHigher saidIt looks to me that the researchers manipulated their system so that more high-energy states were occupied than low ones, thus achieving the negative temperature state.


    Yup—it's just population inversion as occurs in any LASER.

    The problem arises because most people learn temperature as a measure of the kinetic energy of a system, when really it's the [inverse of the] rate at which the entropy of a system changes as a function of the energy.

    Physics <3, LeapHigher
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    Jan 04, 2013 4:43 PM GMT
    TigerTim said
    LeapHigher saidIt looks to me that the researchers manipulated their system so that more high-energy states were occupied than low ones, thus achieving the negative temperature state.


    Yup—it's just population inversion as occurs in any LASER.

    The problem arises because most people learn temperature as a measure of the kinetic energy of a system, when really it's the [inverse of the] rate at which the entropy of a system changes as a function of the energy.

    Physics <3, LeapHigher


    Physics <3 right back at you, TigerTim. I taught about this in my statistical mechanics and thermodynamics class, but you have more practical experience with it than I do.
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    Jan 04, 2013 4:46 PM GMT
    LeapHigher said
    TigerTim said
    LeapHigher saidIt looks to me that the researchers manipulated their system so that more high-energy states were occupied than low ones, thus achieving the negative temperature state.


    Yup—it's just population inversion as occurs in any LASER.

    The problem arises because most people learn temperature as a measure of the kinetic energy of a system, when really it's the [inverse of the] rate at which the entropy of a system changes as a function of the energy.

    Physics <3, LeapHigher


    Physics <3 right back at you, TigerTim. I taught about this in my statistical mechanics and thermodynamics class, but you have more practical experience with it than I do.


    Oh hush, I was like WTF when I read the article and had to go back to the dreaded stat mech book :-)

    The great thing about Physics is that the universe has an infinite capacity to suprise you!
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    Jan 04, 2013 4:53 PM GMT
    TigerTim said


    The great thing about Physics is that the universe has an infinite capacity to suprise you!



    Agreed!
  • Machina

    Posts: 419

    Jan 04, 2013 5:21 PM GMT
    This is cool! Thanks for posting!
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    Jan 04, 2013 6:34 PM GMT
    I suppose it's cool but erm.. Lol does it matter? You wouldn't survive those temperatures! :p
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    Jan 04, 2013 6:35 PM GMT
    So my understanding of quantum and statistical mechanics is juvenile at best, but based on what I am gathering, at an infinite temperature all possible energy states would be occupied uniformly according to the distribution function. However, if the system were heated further, the particles would preferentially gather at higher energy states. The temperature is read as negative because of the way absolute temperature has been historically defined. Not because the system is actually cold.

    This inversion of distribution, or negative temperature cannot occur in a natural system though, because it would require the system to absorb an infinite amount of energy. This phenomenon was only able to occur because the researchers experimentally controlled the amounts of energy the system was able to absorb.

    If anyone could better explain this please post!
  • LJay

    Posts: 11612

    Jan 04, 2013 6:46 PM GMT
    Narciso saidCan't be colder than my bedroom.


    Oh I do wish I could help you there!
  • calibro

    Posts: 8888

    Jan 04, 2013 6:53 PM GMT
    Hawk_Guy13 saidSo my understanding of quantum and statistical mechanics is juvenile at best, but based on what I am gathering, at an infinite temperature all possible energy states would be occupied uniformly according to the distribution function. However, if the system were heated further, the particles would preferentially gather at higher energy states. The temperature is read as negative because of the way absolute temperature has been historically defined. Not because the system is actually cold.

    This inversion of distribution, or negative temperature cannot occur in a natural system though, because it would require the system to absorb an infinite amount of energy. This phenomenon was only able to occur because the researchers experimentally controlled the amounts of energy the system was able to absorb.

    If anyone could better explain this please post!


    cold temperatures = give away energy
    hot temperatures = want/conserve energy

    absolute zero = no higher levels occupied
    infinite temperature = all levels occupied

    negative temperature = manipulated state of low level emptiness and high level occupation such that energy is wanted to be given off despite actual heat being hotter than absolute zero
  • Medjai

    Posts: 2671

    Jan 04, 2013 6:56 PM GMT
    It goes against everything we know about energy and temperature. I'm interested to see where this goes.
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    Jan 04, 2013 7:00 PM GMT
    calibro said

    cold temperatures = give away energy
    hot temperatures = want/conserve energy

    Are you sure this is correct?
    Cold temperature is more tendency of accepting energy. On the other hand Hot temperature is about trying to give away energy . That's why Heat flows from Hotter to Colder object.
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    Jan 04, 2013 7:30 PM GMT
    Shagglot said
    calibro said

    cold temperatures = give away energy
    hot temperatures = want/conserve energy

    Are you sure this is correct?
    Cold temperature is more tendency of accepting energy. On the other hand Hot temperature is about trying to give away energy . That's why Heat flows from Hotter to Colder object.


    Traditionally no, that's not correct. The Clausius interpretation of the second law of thermodynamics is that heat will not flow from a cool body to a warm body spontaneously. In real systems cold temperatures = absorb heat energy; hot temperatures = radiate heat energy.
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    Jan 04, 2013 7:37 PM GMT
    Hawk_Guy13 said

    Traditionally no, that's not correct. The Clausius interpretation of the second law of thermodynamics is that heat will not flow from a cool body to a warm body spontaneously. In real systems cold temperatures = absorb heat energy; hot temperatures = radiate heat energy.

    That was pretty much a layman explanation I was trying to give. I don't know what you are implying but yeah when you place two bodies at different temperature in contact (other mode of transfer exists too) they finally achieve a thermal equilibrium. There is a driving mechanism behind that flow but I guess we aren't going into all the nitty gritty details?
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    Jan 04, 2013 7:39 PM GMT
    Shagglot said
    Hawk_Guy13 said

    Traditionally no, that's not correct. The Clausius interpretation of the second law of thermodynamics is that heat will not flow from a cool body to a warm body spontaneously. In real systems cold temperatures = absorb heat energy; hot temperatures = radiate heat energy.

    That was pretty much a layman explanation I was trying to give. I don't know what you are implying but yeah when you place two bodies at different temperature in contact (other mode of transfer exists too) they finally achieve a thermal equilibrium.


    My comment was directed towards Calibro.