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Colder than absolute zero

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  • Colder than absolute zero

    Is actually hot, apparently: Boffins create quantum gas with temperature BELOW absolute zero • The Register
    "He who joyfully marches to music rank and file, has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would surely suffice." Albert Einstein

  • #2
    "Boffins at the Ludwig Maximilian University in Munich, Germany have literally turned the Kelvin scale on its head, having produced a quantum gas with a temperature below absolute zero"

    and


    "Note that this doesn't mean the resulting system is actually cold, however. Nothing can be colder than absolute zero, which is a theoretical state at which particles have no energy at all. On the contrary, a system with a sub-zero absolute temperature is actually hotter than the same system at any positive temperature"

    I iz confused.
    It didn't look that far on the map...

    Comment


    • #3
      Best wait for the actual article in Science.
      Spiral out, keep going...

      Comment


      • #4
        That's pretty.... 'cool.'

        Ha.

        Comment


        • #5
          If anyone's interested, I highly recommend this documentary on previous efforts.
          Absolute Zero | Watch Free Documentary Online

          Some really interesting stuff around 1 hour 13 in.
          :stupid:

          Comment


          • #6
            interesting idea

            sounds like they have a jar (closed system with respect to matter) containing some potassium atoms in gaseous phase at close to 0K then they compress the atoms with their clever laser EM field wizardry, which leaves a relative vacuum everywhere else in the jar where the atoms are not compressed.

            i assume they are manipulating

            T = temp
            S = entropy

            so the mean T of the jar is 0.1K (or whatever it is) then they frig with the systems entropy by moving all the atoms so they are not evenly distributed throughout the jar which reduces local entropy (local to the condensed atoms). everywhere else in the jar temperature must drop to compensate for the rise in entropy to balance the equation and they have managed to set their starting conditions so this method can achieve conditions implying negative kelvin.

            Originally posted by truewheel View Post
            "Note that this doesn't mean the resulting system is actually cold, however. Nothing can be colder than absolute zero, which is a theoretical state at which particles have no energy at all. On the contrary, a system with a sub-zero absolute temperature is actually hotter than the same system at any positive temperature"

            I iz confused.
            i dont know what they mean by that either its been over 20y since i did 1st principles on temperature, will need to do some refreshing when i have more time to understand what they mean.
            Originally posted by Bendito
            If we get to a stop and we are missing a dozen bikes and you are last, it was your fault. Don't be that guy. No one likes that guy.

            Comment


            • #7
              Colder than absolute zero

              Originally posted by g0zer View Post
              interesting idea

              sounds like they have a jar (closed system with respect to matter) containing some potassium atoms in gaseous phase at close to 0K then they compress the atoms with their clever laser EM field wizardry, which leaves a relative vacuum everywhere else in the jar where the atoms are not compressed.

              i assume they are manipulating

              T = temp
              S = entropy

              so the mean T of the jar is 0.1K (or whatever it is) then they frig with the systems entropy by moving all the atoms so they are not evenly distributed throughout the jar which reduces local entropy (local to the condensed atoms). everywhere else in the jar temperature must drop to compensate for the rise in entropy to balance the equation and they have managed to set their starting conditions so this method can achieve conditions implying negative kelvin.
              By distributing the K atoms evenly they're actually increasing entropy though. If the temperature decreases, they should clump together and increase entropy (presumably) as entropy generally increases with temperature, so by moving them further apart you're increasing the disorder/entropy. Having a read through the article now though so could have my wires crossed a bit

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              • #8
                Colder than absolute zero

                Also, looks like they're manipulating the Gibbs Energy. By decreasing entropy (S) they have to increase temperature (T) to maintain the relationship in the Gibbs Free Energy equation dG=-TdS

                Comment


                • #9
                  Old news.

                  Everyone knows that if you piss off the right woman enough, you'll get a stare back that is way colder than zero degrees Kelvin.
                  One owner. Only driven gently on Sundays. Sold to best offer. First to see will buy. Reward offered for safe return. Coming soon to a cinema near you. Available for a limited time only.

                  My waterbed broke this morning. Oh, I don't have a waterbed. Bugger.

                  Comment


                  • #10
                    Originally posted by truewheel View Post
                    Nothing can be colder than absolute zero, which is a theoretical state at which particles have no energy at all. On the contrary, a system with a sub-zero absolute temperature is actually hotter than the same system at any positive temperature"
                    is what they are saying, is that 0K is where atomic motion ceases and when you dip into negative temperatures atomic motion begins again and that motion is greater than a commensurate + value of temperature? if so it makes no sense to me.
                    Originally posted by Bendito
                    If we get to a stop and we are missing a dozen bikes and you are last, it was your fault. Don't be that guy. No one likes that guy.

                    Comment


                    • #11
                      Re-read the article. Now makes even less sense to me!

                      Comment


                      • #12
                        Re: Colder than absolute zero

                        I read it once then thought I had a grip on it.
                        Spoke to a mate about it and nope.

                        Comment


                        • #13
                          Will negative temperature affect time?
                          “Crashing is shit for you, shit for the bike, shit for the mechanics and shit for the set-up,” Checa told me a while back. “It’s a signal that you are heading in the wrong direction. You want to win but crashing is the opposite. It’s like being in France when you want to go to England and when you crash you go to Spain. That way you’ll never get to England!” -- Carlos Checa

                          Comment


                          • #14
                            "This strange behavior has everything to do with how energy is spread throughout the atoms in a gas known as the ‘Boltzmann distribution’. A gas at any temperature will have different amounts of energy spread amongst its atoms. In a gas that is cooled, the majority of the particles will have low energy states although a few will have higher energy states."

                            "When the Kelvin temperatures become negative in the ultracooled gas, the distributions of energy is the opposite way round so that most of the particles have very high energy states while very few have low ones. In this case, the Boltzmann distribution is said to be ‘inverted’ so that the normal state of affairs is reversed."

                            Beyond 'absolute zero' temperatures get hotter | TG Daily

                            So the case where there are more particles in a high energy state than low energy state means the system is hotter than infinity Kelvin and hence is defined as negative temperature.

                            Comment


                            • #15
                              Originally posted by SIKYSA View Post
                              That's pretty.... 'cool.'

                              Ha.
                              actually its not........

                              absolute zero by definition is when all molecular activity stops. So its basically impossible to read with current devices.
                              Atlas Performance, dyna pumps, " your name goes here"

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