{"id":5015,"date":"2020-04-03T03:55:00","date_gmt":"2020-04-03T03:55:00","guid":{"rendered":"http:\/\/thales.mit.edu\/bush\/?p=5015"},"modified":"2021-04-15T04:14:47","modified_gmt":"2021-04-15T04:14:47","slug":"predictability-in-a-hydrodynamic-pilot-wave-system-resolution-of-walker-tunneling","status":"publish","type":"post","link":"https:\/\/thales.mit.edu\/bush\/index.php\/2020\/04\/03\/predictability-in-a-hydrodynamic-pilot-wave-system-resolution-of-walker-tunneling\/","title":{"rendered":"Walkers tunnel: experiments"},"content":{"rendered":"\n<div class=\"wp-block-cover alignwide has-purple-background-color has-background-dim\"><div class=\"wp-block-cover__inner-container is-layout-flow wp-block-cover-is-layout-flow\">\n<figure class=\"wp-block-image size-large is-style-twentytwentyone-border\"><img loading=\"lazy\" decoding=\"async\" width=\"1916\" height=\"608\" src=\"http:\/\/thales.mit.edu\/bush\/wp-content\/uploads\/2021\/04\/tunnel.png\" alt=\"\" class=\"wp-image-5016\"\/><figcaption>A walking drop approaching a submerged barrier may either be reflected or tunnel across it, the result being unpredictable.<\/figcaption><\/figure>\n\n\n\n<p class=\"tw-text-wide has-extra-small-font-size\">A walker is a macroscopic coupling of a droplet and a capillary wave field that exhibits several quantumlike properties. In 2009, Eddi et al. (2009) showed that walkers may cross a submerged barrier in an unpredictable manner and named this behavior \u201cunpredictable walker tunneling.\u201d In quantum mechanics, tunneling is one of the simplest arrangements where similar unpredictability occurs. In this paper, we investigate how unpredictability can be unveiled for walkers through an experimental study of walker tunneling with precision. We refine both time and position measurements to take into account the fast bouncing dynamics of the system. Tunneling is shown to be unpredictable until a distance of 2.6 mm from the barrier center, where we observe the separation of reflected and transmitted trajectories in the position-velocity phase-space. The unpredictability is unlikely to be attributable to either uncertainty in the initial conditions or to the noise in the experiment. It is more likely due to changes in the drop\u2019s vertical dynamics arising when it interacts with the barrier. We compare this macroscopic system to a tunneling quantum particle that is subjected to repeated measurements of its position and momentum. We show that, despite the different theoretical treatments of these two disparate systems, similar patterns emerge in the position-velocity phase space.<\/p>\n\n\n\n<p class=\"tw-text-wide has-small-font-size\">See paper:  <a href=\"http:\/\/thales.mit.edu\/bush\/wp-content\/uploads\/2021\/04\/Tadrist-PRE2020.pdf\">Tadrist, L., Gilet, T., Schlagheck, P., Bush, J.W.M., <em>Physical Review E<\/em>  (2020).<\/a><\/p>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":5,"featured_media":5017,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15,3],"tags":[],"class_list":["post-5015","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydrodynamic-quantum-analogues","category-pilot-wave-hydrodynamics","entry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v16.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Walkers tunnel: experiments - John W. M. Bush<\/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:\/\/thales.mit.edu\/bush\/index.php\/2020\/04\/03\/predictability-in-a-hydrodynamic-pilot-wave-system-resolution-of-walker-tunneling\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Walkers tunnel: experiments - John W. M. Bush\" \/>\n<meta property=\"og:url\" content=\"https:\/\/thales.mit.edu\/bush\/index.php\/2020\/04\/03\/predictability-in-a-hydrodynamic-pilot-wave-system-resolution-of-walker-tunneling\/\" \/>\n<meta property=\"og:site_name\" content=\"John W. M. 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