{"id":237,"date":"2018-04-23T07:30:40","date_gmt":"2018-04-23T07:30:40","guid":{"rendered":"http:\/\/www.milq.info\/?page_id=237"},"modified":"2026-07-15T16:48:29","modified_gmt":"2026-07-15T14:48:29","slug":"m18_messpostulat","status":"publish","type":"page","link":"https:\/\/www.milq.info\/en\/m18_messpostulat\/","title":{"rendered":"The measurement postulate of quantum mechanics"},"content":{"rendered":"
<\/div>

The fact that a definite value is found in every measurement of a physical observable does not simply follow from the formalism of quantum mechanics; it has to be required separately as an additional postulate.<\/p>\n

The measurement postulate states that a single one of the possible measured values is found. But what are the possible measured values? They are the eigenvalues<\/strong> of the measured observable.<\/p>\n

The concept of the eigenvalue is treated in more detail later (Lesson 8.6, Lesson 9.2). The measurement postulate is the reason why eigenvalues and the solving of eigenvalue equations play such a major role in quantum mechanics: they are the possible measured values.<\/p>\n

Back<\/a><\/p>","protected":false},"excerpt":{"rendered":"

The fact that a definite value is found in every measurement of a physical observable does not simply follow from the formalism of quantum mechanics; it has to be required separately as an additional postulate. The measurement postulate states that a single one of the possible measured values is found. But what are the possible… Continue reading The measurement postulate of quantum mechanics<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-237","page","type-page","status-publish","hentry","without-featured-image"],"yoast_head":"\nThe measurement postulate of quantum mechanics - milq<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.milq.info\/en\/m18_messpostulat\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The measurement postulate of quantum mechanics - milq\" \/>\n<meta property=\"og:description\" content=\"The fact that a definite value is found in every measurement of a physical observable does not simply follow from the formalism of quantum mechanics; it has to be required separately as an additional postulate. The measurement postulate states that a single one of the possible measured values is found. But what are the possible… Continue reading The measurement postulate of quantum mechanics\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.milq.info\/en\/m18_messpostulat\/\" \/>\n<meta property=\"og:site_name\" content=\"milq\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-15T14:48:29+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.milq.info\\\/en\\\/m18_messpostulat\\\/\",\"url\":\"https:\\\/\\\/www.milq.info\\\/en\\\/m18_messpostulat\\\/\",\"name\":\"The measurement postulate of quantum mechanics - milq\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.milq.info\\\/en\\\/#website\"},\"datePublished\":\"2018-04-23T07:30:40+00:00\",\"dateModified\":\"2026-07-15T14:48:29+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.milq.info\\\/en\\\/m18_messpostulat\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[[\"https:\\\/\\\/www.milq.info\\\/en\\\/m18_messpostulat\\\/\"]]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.milq.info\\\/en\\\/m18_messpostulat\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Startseite\",\"item\":\"https:\\\/\\\/www.milq.info\\\/en\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Das Messpostulat der Quantenmechanik\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.milq.info\\\/en\\\/#website\",\"url\":\"https:\\\/\\\/www.milq.info\\\/en\\\/\",\"name\":\"milq\",\"description\":\"Quantenphysik in der Schule\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.milq.info\\\/en\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"The measurement postulate of quantum mechanics - milq","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.milq.info\/en\/m18_messpostulat\/","og_locale":"en_US","og_type":"article","og_title":"The measurement postulate of quantum mechanics - milq","og_description":"The fact that a definite value is found in every measurement of a physical observable does not simply follow from the formalism of quantum mechanics; it has to be required separately as an additional postulate. The measurement postulate states that a single one of the possible measured values is found. But what are the possible… Continue reading The measurement postulate of quantum mechanics","og_url":"https:\/\/www.milq.info\/en\/m18_messpostulat\/","og_site_name":"milq","article_modified_time":"2026-07-15T14:48:29+00:00","twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.milq.info\/en\/m18_messpostulat\/","url":"https:\/\/www.milq.info\/en\/m18_messpostulat\/","name":"The measurement postulate of quantum mechanics - milq","isPartOf":{"@id":"https:\/\/www.milq.info\/en\/#website"},"datePublished":"2018-04-23T07:30:40+00:00","dateModified":"2026-07-15T14:48:29+00:00","breadcrumb":{"@id":"https:\/\/www.milq.info\/en\/m18_messpostulat\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":[["https:\/\/www.milq.info\/en\/m18_messpostulat\/"]]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.milq.info\/en\/m18_messpostulat\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Startseite","item":"https:\/\/www.milq.info\/en\/"},{"@type":"ListItem","position":2,"name":"Das Messpostulat der Quantenmechanik"}]},{"@type":"WebSite","@id":"https:\/\/www.milq.info\/en\/#website","url":"https:\/\/www.milq.info\/en\/","name":"milq","description":"Quantenphysik in der Schule","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.milq.info\/en\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"}]}},"_links":{"self":[{"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/pages\/237","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/comments?post=237"}],"version-history":[{"count":4,"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/pages\/237\/revisions"}],"predecessor-version":[{"id":2784,"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/pages\/237\/revisions\/2784"}],"wp:attachment":[{"href":"https:\/\/www.milq.info\/en\/wp-json\/wp\/v2\/media?parent=237"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}