{"id":8225,"date":"2017-04-07T17:04:55","date_gmt":"2017-04-07T15:04:55","guid":{"rendered":"https:\/\/sciencetonnante.wordpress.com\/?p=8225"},"modified":"2017-04-07T17:04:55","modified_gmt":"2017-04-07T15:04:55","slug":"les-ordinateurs-quantiques","status":"publish","type":"post","link":"https:\/\/scienceetonnante.com\/blog\/2017\/04\/07\/les-ordinateurs-quantiques\/","title":{"rendered":"Les ordinateurs quantiques"},"content":{"rendered":"<p>Ma derni\u00e8re vid\u00e9o parle de ce qui sera peut-\u00eatre la r\u00e9volution technologique de l&rsquo;ann\u00e9e 2017 !<\/p>\n<p><iframe title=\"Les Ordinateurs Quantiques \u2014\u00a0Science \u00e9tonnante #40\" width=\"770\" height=\"433\" data-src=\"https:\/\/www.youtube.com\/embed\/bayTbt_8aNc?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" data-load-mode=\"1\"><\/iframe><\/p>\n<p>Quelques compl\u00e9ments ou pr\u00e9cisions sur ce sujet \u00f4 combien complexe, et parfois caricatur\u00e9.<!--more--><\/p>\n<p>J&rsquo;ai essay\u00e9 de bien rendre le fait qu&rsquo;un ordinateur quantique n&rsquo;\u00e9tait pas simplement un ordinateur plus rapide sur lequel on allait faire tourner Windows, mais une nouvelle mani\u00e8re de concevoir les algorithmes, et que certains probl\u00e8mes ne se pr\u00eataient pas du tout \u00e0 un traitement par ordinateur quantique. Si vous voulez en savoir plus, je vous conseille cet excellent papier de Scott Aaronson <a href=\"http:\/\/www.cs.virginia.edu\/~robins\/The_Limits_of_Quantum_Computers.pdf\" target=\"_blank\" rel=\"noopener\"><em>\u00ab\u00a0The limits of quantum computer\u00a0\u00bb<\/em><\/a> o\u00f9 il explique notamment que certains probl\u00e8mes comme les \u00e9checs ou le go (ou les probl\u00e8mes NP-complets en g\u00e9n\u00e9ral) ne se pr\u00eateront probablement pas \u00e0 une acc\u00e9l\u00e9ration par un algorithme quantique.<\/p>\n<p>Pour les complexit\u00e9s que j&rsquo;ai repr\u00e9sent\u00e9es, j&rsquo;ai utilis\u00e9 celle du <a href=\"https:\/\/fr.wikipedia.org\/wiki\/Crible_alg%C3%A9brique\" target=\"_blank\" rel=\"noopener\">crible alg\u00e9brique<\/a> qui est ce qu&rsquo;on a de mieux pour faire une d\u00e9composition en facteurs premiers, et celle de l&rsquo;algorithme de Shor.<\/p>\n<p>Sur l&rsquo;affaire D-Wave, je suis pass\u00e9 rapidement, mais pour m&rsquo;en remettre une fois de plus \u00e0 l&rsquo;opinion de Scott Aaronson, l&rsquo;ordinateur de D-Wave n&rsquo;a pas d\u00e9montr\u00e9 qu&rsquo;il \u00e9tait capable d&rsquo;aller plus vite qu&rsquo;un ordinateur classique. Je copie\/colle sa conclusion dans un billet dat\u00e9 de 2013<\/p>\n<p><em>D-Wave founder Geordie Rose claims that D-Wave has now accomplished its goal of building a quantum computer that, in his words, is \u201cbetter at something than any other option available.\u201d\u00a0 This claim has been widely and uncritically repeated in the press, so that much of the nerd world now accepts it as fact.\u00a0 However, the claim is not supported by the evidence currently available.\u00a0 It appears that, while the D-Wave machine does outperform certain off-the-shelf solvers, <strong>simulated annealing codes have been written that outperform the D-Wave machine on its own native problem when run on a standard laptop.<\/strong>\u00a0 More research is needed to clarify the issue, but in the meantime, it seems worth knowing that this is where things currently stand.<\/em><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ma derni\u00e8re vid\u00e9o parle de ce qui sera peut-\u00eatre la r\u00e9volution technologique de l&rsquo;ann\u00e9e 2017 ! Quelques compl\u00e9ments ou pr\u00e9cisions sur ce sujet \u00f4 combien complexe, et parfois caricatur\u00e9.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4,6],"tags":[2,42],"class_list":{"0":"post-8225","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-mathematiques","7":"category-physique","8":"tag-arithmetique","9":"tag-mecanique-quantique"},"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/posts\/8225","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/comments?post=8225"}],"version-history":[{"count":0,"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/posts\/8225\/revisions"}],"wp:attachment":[{"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/media?parent=8225"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/categories?post=8225"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceetonnante.com\/blog\/wp-json\/wp\/v2\/tags?post=8225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}