{"id":30090,"date":"2016-09-12T19:49:44","date_gmt":"2016-09-13T02:49:44","guid":{"rendered":"http:\/\/lifeboat.com\/blog\/2016\/09\/viewpoint-mapping-out-the-state-of-a-quantum-system"},"modified":"2017-06-04T14:16:37","modified_gmt":"2017-06-04T21:16:37","slug":"viewpoint-mapping-out-the-state-of-a-quantum-system","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2016\/09\/viewpoint-mapping-out-the-state-of-a-quantum-system","title":{"rendered":"Viewpoint: Mapping Out the State of a Quantum System"},"content":{"rendered":"<p style=\"padding-right: 20px\"><a class=\"aligncenter blog-photo\" href=\"https:\/\/lifeboat.com\/blog.images\/viewpoint-mapping-out-the-state-of-a-quantum-system.jpg\"><\/a><\/p>\n<p>Researchers have developed a new technique to measure the density matrix\u2014a more general way of characterizing the state of a quantum system than that provided by the wave function.<\/p>\n<p>The wave function is the physicist\u2019s usual choice to characterize the state of a quantum system. But a different mathematical object, called a density matrix, is required for systems that are in mixed states, which are a mixture of other, pure quantum states. An example of a pure state is a beam of horizontally or vertically polarized photons, whereas a mixed state would be an uncorrelated statistical mixture of both polarizations. A mixed state would also apply to a system quantum mechanically entangled with its environment. The density matrix provides a complete description of a mixed state, but it also applies to pure states. Usually, experimental measurements of density matrices are indirect reconstructions using data acquired from a series of different kinds of measurements.<\/p>\n<p><!-- Link: <a href=\"http:\/\/physics.aps.org\/articles\/v9\/104\">http:\/\/physics.aps.org\/articles\/v9\/104<\/a> --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Researchers have developed a new technique to measure the density matrix\u2014a more general way of characterizing the state of a quantum system than that provided by the wave function. The wave function is the physicist\u2019s usual choice to characterize the state of a quantum system. But a different mathematical object, called a density matrix, is [\u2026]<\/p>\n","protected":false},"author":395,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2229,1617],"tags":[],"class_list":["post-30090","post","type-post","status-publish","format-standard","hentry","category-mathematics","category-quantum-physics"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/30090","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/395"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=30090"}],"version-history":[{"count":3,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/30090\/revisions"}],"predecessor-version":[{"id":66272,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/30090\/revisions\/66272"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=30090"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=30090"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=30090"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}