{"id":2437,"date":"2025-02-06T09:54:28","date_gmt":"2025-02-06T09:54:28","guid":{"rendered":"https:\/\/www.soscip.org\/us\/?p=2437"},"modified":"2025-02-06T09:54:29","modified_gmt":"2025-02-06T09:54:29","slug":"quantum-entropy-second-law-of-thermodynamics","status":"publish","type":"post","link":"https:\/\/www.soscip.org\/us\/quantum-entropy-second-law-of-thermodynamics\/","title":{"rendered":"Quantum Entropy: How the Second Law of Thermodynamics Holds in the Quantum Realm"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">For decades, physicists believed that quantum mechanics defied the second law of thermodynamics, a fundamental principle governing disorder and entropy in classical systems. However, a groundbreaking study from researchers at the Vienna University of Technology (TU Wien) suggests that entropy in quantum systems also increases over time\u2014just in a different way than previously thought.<\/p>\n\n\n\n<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><h2>Table of Contents<\/h2><nav><ul><li><a href=\"#the-second-law-of-thermodynamics-a-universal-rule\">The Second Law of Thermodynamics: A Universal Rule?<\/a><\/li><li><a href=\"#why-quantum-systems-were-thought-to-defy-entropy\">Why Quantum Systems Were Thought to Defy Entropy<\/a><\/li><li><a href=\"#a-new-perspective-shannon-entropy-in-quantum-systems\">A New Perspective: Shannon Entropy in Quantum Systems<\/a><\/li><li><a href=\"#implications-bridging-thermodynamics-and-quantum-mechanics\">Implications: Bridging Thermodynamics and Quantum Mechanics<\/a><\/li><li><a href=\"#final-thoughts-quantum-entropy-is-real\">Final Thoughts: Quantum Entropy Is Real<\/a><\/li><\/ul><\/nav><\/div>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"the-second-law-of-thermodynamics-a-universal-rule\"><strong>The Second Law of Thermodynamics: A Universal Rule?<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/www.soscip.org\/us\/quantum-entropy-second-law-of-thermodynamics\/\" data-type=\"link\" data-id=\"https:\/\/www.soscip.org\/us\/quantum-entropy-second-law-of-thermodynamics\/\">second law of thermodynamics<\/a> states that the entropy (or disorder) of an isolated system always increases over time until it reaches equilibrium. This principle explains everyday phenomena such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Ice melting into water<\/li>\n\n\n\n<li>A tidy room gradually becoming messier<\/li>\n\n\n\n<li>A hot cup of coffee cooling down<\/li>\n\n\n\n<li>Aging and the irreversible passage of time<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Entropy is often associated with chaos, randomness, and the loss of usable energy. However, quantum systems operate under different rules, leading some to believe that the second law does not apply at the microscopic scale.<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/motorsport-400-hp-water-injected-hydrogen-engine\/\" data-type=\"post\" data-id=\"2240\">Revolutionizing Motorsport: The Breakthrough 400 HP Water-Injected Hydrogen Engine and Its Role in Sustainable Racing<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/quantum-computing-dna-could-replace-silicon\/\" data-type=\"post\" data-id=\"2392\">Quantum Computing Breakthrough: DNA Could Replace Silicon in Future Supercomputers<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/comet-c-2024-g3-atlas-a-dazzling-celestial-event\/\" data-type=\"post\" data-id=\"2244\">Comet C\/2024 G3 (ATLAS): A Dazzling Celestial Event Redefining Astronomy, Technology, and Our Connection to the Cosmos<\/a><\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"why-quantum-systems-were-thought-to-defy-entropy\"><strong>Why Quantum Systems Were Thought to Defy Entropy<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In the 1930s, mathematician John von Neumann published a series of papers arguing that the entropy of a quantum system remains constant over time\u2014provided we have complete knowledge of its quantum state. His calculations suggested that quantum systems could remain perfectly ordered, seemingly contradicting classical thermodynamics.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, von Neumann&#8217;s approach assumed a level of precision that quantum physics itself forbids. Due to the uncertainty principle and the probabilistic nature of quantum mechanics, it is impossible to have complete knowledge of a system&#8217;s state. This means the conventional approach to measuring entropy in quantum mechanics needed to be re-evaluated.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"a-new-perspective-shannon-entropy-in-quantum-systems\"><strong>A New Perspective: Shannon Entropy in Quantum Systems<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The new study from TU Wien challenges von Neumann\u2019s interpretation by redefining entropy in a quantum context. Instead of using von Neumann entropy, the researchers applied <strong>Shannon entropy<\/strong>, a concept introduced by mathematician Claude Shannon in 1948.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>What Is Shannon Entropy?<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Shannon entropy measures uncertainty in the outcome of a specific measurement. In simple terms, it quantifies how much new information we gain when observing a system.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If a measurement always produces the same result with 100% certainty, the Shannon entropy is <strong>zero<\/strong> (no new information is gained).<\/li>\n\n\n\n<li>If multiple outcomes are equally probable, the Shannon entropy is <strong>high<\/strong> (each measurement provides new information).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Applying Shannon Entropy to Quantum Systems<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Consider an electron whose spin can be either <strong>up<\/strong> or <strong>down<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If we already know the spin is <strong>100% up<\/strong>, the Shannon entropy is <strong>zero<\/strong> because no new information is gained from measuring it.<\/li>\n\n\n\n<li>If the spin is <strong>50% up and 50% down<\/strong>, the Shannon entropy is <strong>high<\/strong> because we gain new knowledge each time we measure the spin.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">As time progresses, the entropy of the system increases, reflecting growing uncertainty. Eventually, it stabilizes at a maximum level, just like in classical thermodynamics, where entropy reaches equilibrium.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"implications-bridging-thermodynamics-and-quantum-mechanics\"><strong>Implications: Bridging Thermodynamics and Quantum Mechanics<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The study reveals that the second law of thermodynamics holds true even in fully isolated quantum systems\u2014when entropy is measured correctly. This breakthrough unites thermodynamics with quantum physics, offering new insights into:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Quantum information theory<\/strong>: Understanding entropy in quantum systems is crucial for advancements in quantum computing.<\/li>\n\n\n\n<li><strong>The arrow of time<\/strong>: The study supports the idea that time\u2019s forward progression is driven by increasing entropy, even at the quantum scale.<\/li>\n\n\n\n<li><strong>Complex quantum systems<\/strong>: The findings apply not only to individual quantum particles but also to multi-particle systems with diverse possible outcomes.<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/invention-turns-plastic-waste-home-energy\/\" data-type=\"post\" data-id=\"2092\">Revolutionary Invention Turns Plastic Waste into Home Energy \u2013 No Solar Panels Needed!<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/deepseek-chinese-ai-startup-disrupting-global\/\" data-type=\"post\" data-id=\"2115\">DeepSeek: The Chinese AI Startup Disrupting the Global AI Industry<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.soscip.org\/us\/3-strategic-steps-transform-accounting-firms\/\" data-type=\"post\" data-id=\"1986\">Beyond AI Hype: Three Strategic Steps to Transform Accounting Firms with Practical AI Integration<\/a><\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"final-thoughts-quantum-entropy-is-real\"><strong>Final Thoughts: Quantum Entropy Is Real<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Entropy\u2014whether in a messy room or a quantum particle\u2014represents a fundamental principle of the universe. The TU Wien study confirms that quantum mechanics does not violate the second law of thermodynamics; it simply follows a different type of entropy.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By redefining how we measure disorder in the quantum world, scientists are uncovering deeper connections between classical and quantum physics, paving the way for future discoveries in quantum computing, thermodynamics, and beyond.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>For decades, physicists believed that quantum mechanics defied the second law of thermodynamics, a fundamental principle governing disorder and entropy in classical systems. However, a groundbreaking study from researchers at the Vienna University of Technology (TU Wien) suggests that entropy in quantum systems also increases over time\u2014just in a different way than previously thought. The&nbsp;<a class=\"read-more\" href=\"https:\/\/www.soscip.org\/us\/quantum-entropy-second-law-of-thermodynamics\/\">Continue reading<\/a><\/p>\n","protected":false},"author":1,"featured_media":2440,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[37,31,32],"class_list":["post-2437","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-innovation","tag-fiction","tag-science","tag-technology"],"_links":{"self":[{"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/posts\/2437","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/comments?post=2437"}],"version-history":[{"count":2,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/posts\/2437\/revisions"}],"predecessor-version":[{"id":2439,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/posts\/2437\/revisions\/2439"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/media\/2440"}],"wp:attachment":[{"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/media?parent=2437"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/categories?post=2437"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.soscip.org\/us\/wp-json\/wp\/v2\/tags?post=2437"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}