Negative Temperature
Certain systems can have negative temperatures, hotter than any positive-temperature system. Predicted by Lars Onsager in 1949, they exhibit emergent ordering at high energies, with decreased entropy as energy increases.
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Negative temperature is a concept where certain systems can have a temperature expressed as a negative quantity on the Kelvin or Rankine scales, indicating they are hotter than any system with a positive temperature. When a negative-temperature system interacts with a positive-temperature system, heat flows from the negative to the positive temperature system. The possibility of negative temperatures was first predicted by Lars Onsager in 1949, based on systems with bounded phase space. These systems exhibit emergent ordering at high energies, contrary to the common understanding that increased energy leads to increased disorder. Negative temperatures are associated with a decrease in entropy as energy increases, in contrast to systems with positive temperatures where entropy increases with added energy. The distribution of energy states in systems with limited states allows for the existence of negative temperatures, where higher energy states are more likely to be occupied than lower energy ones. Negative temperature systems are not colder than absolute zero but are hotter than infinite temperature, representing a unique aspect of thermodynamic behavior.
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6 comments > Not simply, ordinarily cold. Ordinary cold was merely the absence of movement. It has passed through there a long time ago, had gone straight through commonplace idleness and out the far side. It put more effort into staying still than most things put into movement.We experience temperature, however, as the amount of heat coming from an object. Really the experience of temperature should then be something like -dS/dQ which is like how readily the system gives up energy. The more entropy increases when the energy in the system decreases, the more 'hot' it feels.
Therefore, our 'experience' of temperature is like -1/T = -dS/dQ. The hottest temperatures are negative numbers close to zero.
Additionally, infinity temperature is simply the crossover point where adding additional heat begins to decrease entropy instead of increasing it. I.e. the places to store the additional heat are running out.
The concept still seems "off" to me intuitively, like an abuse of notation or something, although I understand it logically.
> SI temperature/coldness conversion scale: Temperatures on the Kelvin scale are shown in blue (Celsius scale in green, Fahrenheit scale in red), coldness values in gigabyte per nanojoule are shown in black
gigabyte per nanojoule? wat? I understand that this is some measure of entropy but the article never mentions bytes again which is slightly baffling.
How to interpret this sentence?
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