The Tsallis Entropic Index <em>q</em> as a Measure of Distance from Thermal Equilibrium in Paramagnetic Spin Lattices

<p id="p1">For super&ndash;systems <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic></em>&nbsp;+&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://ww...

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Autores principales: Masthay, Mark, Benton, Charles, Guerrieri, Luke, Keil, Robert
Formato: Capítulo de libro
Lenguaje:inglés
Publicado: IntechOpen 2024
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Acceso en línea:https://www.intechopen.com/chapters/89411
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Sumario:<p id="p1">For super&ndash;systems <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic></em>&nbsp;+&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">D</italic></em> comprised of combinations of sub&ndash;systems <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic></em> and <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">D</italic></em> which obey Boltzmann thermo&ndash;statistics, the entropy <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">S</italic></em> is additive (<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">S<sub>C</sub></italic></em>&nbsp;+&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">S<sub>D</sub></italic></em>&nbsp;=&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">S</italic></em><sub><em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic></em>&nbsp;+&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">D</italic></em></sub>) and extensive and the temperature <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T</italic></em> is intensive. However, because of finite&ndash;size effects, the entropy becomes non&ndash;additive and non&ndash;extensive, and the temperature non&ndash;intensive, for very small systems. In such cases, the Tsallis entropic index <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">q</italic></em> quantifies the extent to which the entropy is non&ndash;additive and the temperature is non&ndash;intensive. In this paper, we use paramagnetic spin lattices (PSLs) as model systems to demonstrate that <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">q</italic></em> is not only a measure of entropic non&ndash;extensivity and temperature non&ndash;intensivity, but also the extent to which sub&ndash;PSL/super&ndash;PSL combinations of various sizes deviate from the global thermal equilibrium condition <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T<sub>C</sub></italic></em>&nbsp;=&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T<sub>D</sub></italic></em>&nbsp;=&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">T</italic></em><sub><em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C</italic></em>&nbsp;+&nbsp;<em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">D</italic></em></sub>. Our results demonstrate that <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">q</italic></em>&nbsp;&rarr;&nbsp;1 as global thermal equilibrium is approached regardless of system size, thus indicating that <em><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">q</italic></em> is an effective measure of distance from equilibrium.</p>
ISBN:978-0-85014-099-6
DOI:10.5772/intechopen.114829