		{"id":17602,"date":"2016-11-22T21:38:05","date_gmt":"2016-11-22T20:38:05","guid":{"rendered":"http:\/\/www.erbium.at\/FF\/?p=17602"},"modified":"2020-10-16T10:01:28","modified_gmt":"2020-10-16T08:01:28","slug":"17602","status":"publish","type":"post","link":"https:\/\/www.erbium.at\/FF\/17602\/","title":{"rendered":"Crossover from a BEC to a macrodroplet"},"content":{"rendered":"<p style=\"text-align: right; line-height: 0.1;\"><span style=\"font-size: xx-small;\">(c) of image: Harald Ritsch<\/span><\/p>\n<p style=\"text-align: left;\"><strong>Now in Physical Review X! <\/strong><\/p>\n<p>Together with our theory colleagues from Hannover (Luis Santos and Falk W\u00e4chtler), we have investigated the formation of a macrodroplet state in an ultracold bosonic gas of erbium atoms. Our paper has been now published in PRX and featured in Physics! MORE<\/p>\n<p><!--more--> By precisely changing the <span class=\"aps-inline-formula\"><span id=\"MathJax-Element-1-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-1\" class=\"math\"><span id=\"MathJax-Span-2\" class=\"mrow\"><span id=\"MathJax-Span-3\" class=\"mi\">s<\/span><\/span><\/span><\/span><\/span>-wave scattering length below the dipolar length, defined by the dipole-dipole interaction, we observe a smooth crossover of the ground state from a dilute Bose-Einstein condensate to a dense macrodroplet of more than <span class=\"aps-inline-formula\"><span id=\"MathJax-Element-2-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-4\" class=\"math\"><span id=\"MathJax-Span-5\" class=\"mrow\"><span id=\"MathJax-Span-6\" class=\"mrow\"><span id=\"MathJax-Span-7\" class=\"mn\">20.000<\/span><span id=\"MathJax-Span-14\" class=\"mtext\"><\/span><span id=\"MathJax-Span-15\" class=\"mtext\">\u2009<\/span><span id=\"MathJax-Span-16\" class=\"mi\">atoms<\/span><\/span><\/span><\/span><\/span><\/span>. By comparing collective excitations and loss features with numerical simulations, we could show, that quantum fluctuations play the stabilizing role that prevents the ultracold gas from becoming unstable, as naively expected in the standard meanfield picture. In another set of experiments, we perform expansion measurements and could show that although self-bound solutions are prevented by losses, the interplay between quantum stabilization and losses results in a minimal time-of-flight expansion velocity for a finite s-wave scattering length.<\/p>\n<p><a href=\"http:\/\/journals.aps.org\/prx\/abstract\/10.1103\/PhysRevX.6.041039\" target=\"_blank\" rel=\"noopener noreferrer\">Link to paper<\/a><\/p>\n<p><span style=\"font-size: xx-small;\">\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Now in Physical Review X!<\/p>\n<p>Together with our theory colleagues from Hannover (Luis Santos and Falk W\u00e4chtler), we have investigated the formation of a macrodroplet state in an ultracold bosonic gas of erbium atoms. Our paper has been now published in PRX and featured in Physics!<\/p>\n","protected":false},"author":1,"featured_media":17763,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[38,3],"tags":[],"_links":{"self":[{"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/posts\/17602"}],"collection":[{"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/comments?post=17602"}],"version-history":[{"count":20,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/posts\/17602\/revisions"}],"predecessor-version":[{"id":38666,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/posts\/17602\/revisions\/38666"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/media\/17763"}],"wp:attachment":[{"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/media?parent=17602"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/categories?post=17602"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.erbium.at\/FF\/wp-json\/wp\/v2\/tags?post=17602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}