PartagerUne étude mathématique présente une dérivation générale et une quantification du troisième principe de la thermodynamique (en anglais)
Deux physiciens de l'University College de Londres ont fourni une dérivation du "principe d'inatteignabilité", qui stipule que le zéro absolu est physiquement inaccessible en une quantité finie d’opérations.
The third law of thermodynamics, developed in the early 20th, has a controversial past and a number of fomulations due to Planck, Einstein, and Nernst. Its most accepted version is the unattainability principle: it states that any process cannot reach absolute zero temperature in a finite number of steps and within a finite time.
In a study* published on the journal Nature Communications on March 2017,Lluis Masanes and Jonathan Oppenheim "provide a derivation of the [unattainability] principle that applies to arbitrary cooling processes, even those exploiting the laws of quantum mechanics or involving an infinite-dimensional reservoir. [They] quantify the resources needed to cool a system to any temperature, and translate these resources into the minimal time or number of steps, by considering the notion of a thermal machine that obeys similar restrictions to universal computers. [They] generally find that the obtainable temperature can scale as an inverse power of the cooling time. The results of the study also clarify the connection between two versions of the third law (the unattainability principle and the heat theorem), and place ultimate bounds on the speed at which information can be erased."
*Masanes, L. & Oppenheim, J. A general derivation and quantification of the third law of thermodynamics. Nature Communications. 8, 14538 doi: 10.1038/ncomms14538 (2017).
Picture: Walther Nernst (1864-1941).
In a study* published on the journal Nature Communications on March 2017,Lluis Masanes and Jonathan Oppenheim "provide a derivation of the [unattainability] principle that applies to arbitrary cooling processes, even those exploiting the laws of quantum mechanics or involving an infinite-dimensional reservoir. [They] quantify the resources needed to cool a system to any temperature, and translate these resources into the minimal time or number of steps, by considering the notion of a thermal machine that obeys similar restrictions to universal computers. [They] generally find that the obtainable temperature can scale as an inverse power of the cooling time. The results of the study also clarify the connection between two versions of the third law (the unattainability principle and the heat theorem), and place ultimate bounds on the speed at which information can be erased."
*Masanes, L. & Oppenheim, J. A general derivation and quantification of the third law of thermodynamics. Nature Communications. 8, 14538 doi: 10.1038/ncomms14538 (2017).
Picture: Walther Nernst (1864-1941).