{"id":5115,"date":"2024-12-24T17:20:43","date_gmt":"2024-12-24T16:20:43","guid":{"rendered":"https:\/\/www.zsvltava.cz\/fyzika\/?p=5115"},"modified":"2025-04-10T09:56:29","modified_gmt":"2025-04-10T07:56:29","slug":"maxwelluv-demon-myticky-narusitel-druheho-zakona-termodynamiky","status":"publish","type":"post","link":"https:\/\/www.zsvltava.cz\/fyzika\/?p=5115","title":{"rendered":"Maxwell\u016fv d\u00e9mon – mytick\u00fd naru\u0161itel druh\u00e9ho z\u00e1kona termodynamiky"},"content":{"rendered":"

Maxwell\u016fv d\u00e9mon je fascinuj\u00edc\u00ed hypotetick\u00fd koncept z oblasti fyziky, kter\u00fd zpochyb\u0148uje jeden z fundament\u00e1ln\u00edch princip\u016f termodynamiky \u2014 druh\u00fd z\u00e1kon. Tento z\u00e1kon stanovuje, \u017ee entropie izolovan\u00e9ho syst\u00e9mu nikdy nekles\u00e1, co\u017e lze interpretovat jako nevyhnutelnost degradace energie na nepou\u017eitelnou formu. Maxwell\u016fv d\u00e9mon n\u00e1s v\u0161ak nut\u00ed polo\u017eit si ot\u00e1zku: je tomu opravdu tak?<\/strong><\/p>\n

P\u0159\u00edb\u011bh Maxwellova d\u00e9mona<\/h2>\n

Koncept poprv\u00e9 formuloval skotsk\u00fd fyzik James Clerk Maxwell<\/a> v roce 1867. P\u0159edstavme si uzav\u0159en\u00fd syst\u00e9m, kter\u00fd je rozd\u011blen na dv\u011b \u010d\u00e1sti p\u0159ep\u00e1\u017ekou s mal\u00fdm otvorem. Maxwell si p\u0159edstavoval hypotetickou bytost \u2014 d\u00e9mona \u2014 kter\u00e1 by dok\u00e1zala manipulovat s jednotliv\u00fdmi molekulami plynu. Tento d\u00e9mon by otv\u00edral a zav\u00edral otvor podle toho, jak rychle se jednotliv\u00e9 molekuly pohybuj\u00ed: rychlej\u0161\u00ed molekuly by propou\u0161t\u011bl do jedn\u00e9 \u010d\u00e1sti a pomalej\u0161\u00ed do druh\u00e9.<\/p>\n

T\u00edm by do\u0161lo k naru\u0161en\u00ed rovnov\u00e1hy \u2014 jedna strana by se oh\u0159\u00e1la a druh\u00e1 ochladila, ani\u017e by bylo vykon\u00e1no jak\u00e9koli vnit\u0159n\u00ed pr\u00e1ce. To by znamenalo, \u017ee entropie syst\u00e9mu<\/a> klesla, co\u017e je v rozporu s druh\u00fdm z\u00e1konem termodynamiky.<\/p>\n

Fyzik\u00e1ln\u00ed dilemata<\/h2>\n

Maxwell\u016fv d\u00e9mon vyvolal vlnu diskus\u00ed mezi fyziky. Hlavn\u00ed ot\u00e1zkou bylo, zda je takov\u00e1 manipulace skute\u010dn\u011b mo\u017en\u00e1 a zda nen\u00ed samotn\u00fd d\u00e9mon n\u011bjak\u00fdm zp\u016fsobem omezen fyzik\u00e1ln\u00edmi z\u00e1kony. V roce 1929 ma\u010farsk\u00fd fyzik Le\u00f3 Szil\u00e1rd navrhl, \u017ee aby d\u00e9mon mohl vykon\u00e1vat svou \u010dinnost, mus\u00ed n\u011bjak\u00fdm zp\u016fsobem z\u00edsk\u00e1vat informace o rychlosti molekul. Tento proces z\u00edsk\u00e1v\u00e1n\u00ed informac\u00ed a jejich zpracov\u00e1n\u00ed by v\u0161ak vy\u017eadoval energii, co\u017e by ve fin\u00e1le vedlo ke zv\u00fd\u0161en\u00ed entropie cel\u00e9ho syst\u00e9mu.<\/p>\n

Informace a entropie<\/h2>\n

V 20. stolet\u00ed spojil koncept Maxwellova d\u00e9mona teorii informace s termodynamikou. Americk\u00fd fyzik Rolf Landauer v roce 1961 formuloval princip, podle n\u011bj\u017e je maz\u00e1n\u00ed informac\u00ed v\u017edy spojeno se zv\u00fd\u0161en\u00edm entropie<\/a>. Pokud d\u00e9mon mus\u00ed mazat star\u00e9 informace, aby mohl zpracov\u00e1vat nov\u00e9, tento proces zaji\u0161\u0165uje, \u017ee druh\u00fd z\u00e1kon z\u016fst\u00e1v\u00e1 nenaru\u0161en.<\/p>\n","protected":false},"excerpt":{"rendered":"

Maxwell\u016fv d\u00e9mon je fascinuj\u00edc\u00ed hypotetick\u00fd koncept z oblasti fyziky, kter\u00fd zpochyb\u0148uje jeden z fundament\u00e1ln\u00edch princip\u016f termodynamiky \u2014 druh\u00fd z\u00e1kon. Tento z\u00e1kon stanovuje, \u017ee entropie izolovan\u00e9ho …. <\/p>\n","protected":false},"author":1,"featured_media":5811,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[67],"class_list":["post-5115","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-zajimavosti","tag-historie"],"_links":{"self":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/5115","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5115"}],"version-history":[{"count":0,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/5115\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/media\/5811"}],"wp:attachment":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5115"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5115"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5115"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}