{"id":262,"date":"2005-09-24T13:05:31","date_gmt":"2005-09-24T17:05:31","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=262"},"modified":"2005-10-03T19:28:19","modified_gmt":"2005-10-03T23:28:19","slug":"diracs-hidden-geometry","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=262","title":{"rendered":"Dirac&#8217;s Hidden Geometry"},"content":{"rendered":"<p>There&#8217;s an interesting article by Graham Farmelo in last week&#8217;s Nature, entitled <a href=\"http:\/\/www.nature.com\/nature\/journal\/v437\/n7057\/pdf\/437323a.pdf\">Dirac&#8217;s Hidden Geometry<\/a>.   Most people think of Dirac as a brilliant algebraist, but he himself claimed that his motivations and way of thinking were much more geometrical than algebraic.  Farmelo&#8217;s article contains an amusing account of how Roger Penrose tried to get Dirac to explain how projective geometry had influenced his work in quantum mechanics. Dirac gave a talk about this at Boston University in 1972, but, after giving a presentation about projective geometry, stopped before explaining the relation to quantum mechanics. Penrose, the moderator, asked Dirac about the relation to quantum mechanics, and in answer &#8220;Dirac gave his trademark shake of the head, and declined to speak.&#8221;<\/p>\n<p>Several historians of science have tried to figure out what Dirac&#8217;s geometrical motivations were.  This question is dealt with in Olivier Darrigol&#8217;s very interesting book (which is now available on-line) <a href=\"http:\/\/ark.cdlib.org\/ark:\/13030\/ft4t1nb2gv\/\">From c-numbers to q-numbers: The Classical Analogy in the History of Quantum Theory<\/a>.  The material about Dirac and projective geometry is in chapter XI.  On the same topic, there&#8217;s also an article by Peter Galison published in 2000 in the journal Representations, entitled <a href=\"http:\/\/links.jstor.org\/sici?sici=0734-6018%28200023%290%3A72%3C145%3ATSDPDH%3E2.0.CO%3B2-D\">The Suppressed Drawing: Paul Dirac&#8217;s Hidden Geometry<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>There&#8217;s an interesting article by Graham Farmelo in last week&#8217;s Nature, entitled Dirac&#8217;s Hidden Geometry. Most people think of Dirac as a brilliant algebraist, but he himself claimed that his motivations and way of thinking were much more geometrical than &hellip; <a href=\"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=262\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","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":[1],"tags":[],"class_list":["post-262","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/262","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=262"}],"version-history":[{"count":0,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/262\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}