{"id":240,"date":"2010-09-04T15:38:27","date_gmt":"2010-09-04T20:38:27","guid":{"rendered":"http:\/\/blog.richmond.edu\/physicsbunn\/2010\/09\/04\/quantum-mechanics-is-strange-but-not-that-strange\/"},"modified":"2010-09-04T15:38:27","modified_gmt":"2010-09-04T20:38:27","slug":"quantum-mechanics-is-strange-but-not-that-strange","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/physicsbunn\/2010\/09\/04\/quantum-mechanics-is-strange-but-not-that-strange\/","title":{"rendered":"Quantum mechanics is strange, but not that strange"},"content":{"rendered":"

There’s a piece in Discove<\/em>r<\/em><\/a> describing an experimental result that, according to the article, “shows that measurements performed in the future can influence the present.”\u00a0 This sort of thing should always set off your extreme-skepticism response.\u00a0 Sure enough, although the experimental result is pretty cool, it absolutely in no way implies backward-in-time causation.\u00a0 Even by the standards of other silly woo-woo articles on quantum mechanics, this one is pretty bad.<\/p>\n

If you read the article carefully, or better yet if you read this more technical and more accurate description,<\/a> you’ll find that what’s actually been shown is that later measurement results are correlated with earlier ones.\u00a0 To be specific, suppose you prepare a bunch of particles at one time,\u00a0 then make a measurement on them at an intermediate time, then finally make another measurement at\u00a0 a later time.\u00a0 You then retroactively split the particles into two groups based on the result of that later measurement.\u00a0 What’s been discovered is that those two groups yield different outcomes on the earlier measurements.<\/p>\n

That’s not at all surprising, and it in no way implies backwards-in-time causation.\u00a0 Suppose we both know that Professor Bertlmann<\/a>‘s socks never match.\u00a0 Suppose I look at one of his socks now, and you look at his other sock an hour from now.\u00a0 If you “measure” that his sock is green, then you can conclude that my measurement must have yielded non-green.\u00a0 Do you think that your measurement somehow sent influences back in time, causing my measurement to be non-green?\u00a0 If so, then you should think the same thing about these quantum mechanics results.\u00a0 If not, not.<\/p>\n

As far as I can tell (this isn’t my field), the precise nature of the correlations that result in this experiment are interesting and potentially quite useful in allowing more accurate measurements of various things that people are interested in.\u00a0 So it’s a good experiment.\u00a0 It just doesn’t have the amazing philosophical implications imputed to it.<\/p>\n","protected":false},"excerpt":{"rendered":"

There’s a piece in Discover describing an experimental result that, according to the article, “shows that measurements performed in the future can influence the present.”\u00a0 This sort of thing should always set off your extreme-skepticism response.\u00a0 Sure enough, although the experimental result is pretty cool, it absolutely in no way implies backward-in-time causation.\u00a0 Even by … Continue reading Quantum mechanics is strange, but not that strange<\/span><\/a><\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-240","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/240","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/comments?post=240"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/240\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/media?parent=240"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/categories?post=240"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/tags?post=240"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}