{"id":345,"date":"2010-11-29T12:27:15","date_gmt":"2010-11-29T12:27:15","guid":{"rendered":"http:\/\/junq.info\/?p=345"},"modified":"2011-02-16T21:32:23","modified_gmt":"2011-02-16T21:32:23","slug":"to-be-entangled-or-not-to-be-entangled","status":"publish","type":"post","link":"http:\/\/junq.info\/?p=345","title":{"rendered":"To be entangled, or not to be entangled?"},"content":{"rendered":"<p><em>Question of the week, 29.12.2010<\/em><\/p>\n<p>Quantum computing is a fascinating field. That&#8217;s the world (quantum mechanical), where &#8220;some of impossible is possible&#8221;. For example efficient factoring of integers (Shor&#8217;s algorithm). But what&#8217;s the source of quantum computers&#8217; power? <\/p>\n<p>People believed that it&#8217;s entanglement &#8211; a quantum mechanical quality describing the interdependence of measurements made between parts of a quantum system. Entanglement plays a key role e.g. in quantum teleportation, superdense coding, quantum pseudotelepathy and many many others. In fact, it has been shown that without <em>enough<\/em> entanglement existing at some point in the process of a computation, quantum computer cannot outperform a classical one. <\/p>\n<p>It&#8217;s quite surprising that as was shown recently (see references in [2]), also opposite is bad. Too much of entanglement in case of so called quantum one-way computing (one of analogs of a circuit model) causes that this computational model cannot outperform classical computers. So let me cite Dave Bacon [2]: &#8220;Entanglement, like most good things in life, must be consumed in moderation.&#8221;<\/p>\n<p>References:<\/p>\n<p>[1] Nielsen and Chuang; Quantum Computation and Quantum Information; Cambridge University Press, 2000 <\/p>\n<p>[2] <a href=\"http:\/\/physics.aps.org\/articles\/v2\/38\">http:\/\/physics.aps.org\/articles\/v2\/38<\/a><\/p>\n<p>Libor Veis<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Quantum computing is a fascinating field. That&#8217;s the world (quantum mechanical), where &#8220;some of impossible is possible&#8221;. For example efficient factoring of integers (Shor&#8217;s algorithm). But what&#8217;s the source of quantum computers&#8217; power? (Question of the Week, 29.12.2010)<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":true,"template":"","format":"standard","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[6],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/345"}],"collection":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=345"}],"version-history":[{"count":2,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/345\/revisions"}],"predecessor-version":[{"id":577,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/345\/revisions\/577"}],"wp:attachment":[{"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=345"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}