{"id":40,"date":"2009-01-12T15:45:25","date_gmt":"2009-01-12T02:45:25","guid":{"rendered":"https:\/\/blog.waikato.ac.nz\/physicsstop\/2009\/01\/12\/levitation\/"},"modified":"2009-01-12T15:45:25","modified_gmt":"2009-01-12T02:45:25","slug":"levitation","status":"publish","type":"post","link":"https:\/\/blog.waikato.ac.nz\/physicsstop\/2009\/01\/12\/levitation\/","title":{"rendered":"Levitation"},"content":{"rendered":"<p>Last Thursday while browsing a popular NZ-based website an article caught my attention: <a target=\"_blank\" href=\"http:\/\/www.stuff.co.nz\/4812727a12.html\">&#8216;Scientists learn to levitate objects&#8217;<\/a>. Images from Harry Potter films flashed before my eyes, and I thought this had to be something worth checking out. And it was, for two reasons. First, because the article is a surprisingly accurate piece of science writing&nbsp;for &nbsp;mainstream media, and secondly, it concerns a very curious quantum mechanical effect.<\/p>\n<p><!--more--><\/p>\n<p>In my not-all-that-long science career I have come to the conclusion that you never trust a journalist to write a story about science. Usually they have an uncanny knack of removing all the key concepts and facts and replacing them with whatever fictional construction is required in order to support&nbsp;the message they wish to sensationalise. So I was pleasantly surprised when I refered to the <a target=\"_blank\" href=\"http:\/\/www.nature.com\/nature\/journal\/v457\/n7226\/full\/457156a.html\">original article <\/a>by Steve Lamoreaux in the journal Nature and discovered that the journalist really had accurately portrayed the work that had been done. Admittedly, the title was a touch misleading, with the &#8216;objects&#8217; in question likely to be not much bigger than molecules, but I can forgive that &#8211; I probably won&#8217;t have clicked on the article otherwise.<\/p>\n<p>Which brings me on to the work itself. It concerns the Casimir force, which is decidedly strange. Its very existence is a result of quantum mechanics, can therefore be considered an experimental &#8216;proof&#8217; of quantum theory. In a sense, the Casimir force is &#8216;something for nothing&#8217;; the idea is that &#8216;stuff&#8217; can appear spontaneously out of a vacuum, so long as it only does so for a short period of time. This &#8216;stuff&#8217; hangs around long enough to interact with objects surrounding the vacuum and in effect provide forces between them. In the case of this work, it is a repulsive force that can potentially levitate something.<\/p>\n<p>Can something really come out of nothing?&nbsp; Let&#8217;s use an&nbsp; example from economics that is becoming depressingly familiar. There is talk in some countries of overnight interest rates dropping to zero. In that case, a bank can borrow money from its country&#8217;s central bank, overnight, for zero percent interest. It can take as much as it likes, so long as it pays all of it back exactly a short period of time later. Why bother? Because that keeps the bank functioning, and a functioning bank acts as a source of finance to business in general.&nbsp;&nbsp; No money is &#8216;created&#8217; &#8211; it gets borrowed and repayed, but in a time-span just long enough to make a difference.&nbsp; That&#8217;s what&#8217;s happening (sort of) with the Casimir force.<\/p>\n<p>Incidently, some people think that the universe exists because of one of these &#8216;borrow &#8216;stuff&#8217; for a short time&#8217; events. I&#8217;m far from convinced &#8211; the universe contains a whole lot of stuff, and it has existed for an awfully long time without having paid it back. The debt collectors seem long overdue.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Last Thursday while browsing a popular NZ-based website an article caught my attention: &#8216;Scientists learn to levitate objects&#8217;. Images from Harry Potter films flashed before my eyes, and I thought this had to be something worth checking out. And it was, for two reasons. First, because the article is a surprisingly accurate piece of science [&hellip;]<\/p>\n","protected":false},"author":20,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Levitation : Physics Stop<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.waikato.ac.nz\/physicsstop\/2009\/01\/12\/levitation\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Levitation : Physics Stop\" \/>\n<meta property=\"og:description\" content=\"Last Thursday while browsing a popular NZ-based website an article caught my attention: &#8216;Scientists learn to levitate objects&#8217;. 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