{"id":5546,"date":"2020-01-28T09:40:19","date_gmt":"2020-01-28T09:40:19","guid":{"rendered":"http:\/\/blogs.scienceforums.net\/ajb\/?p=5546"},"modified":"2020-01-28T09:40:19","modified_gmt":"2020-01-28T09:40:19","slug":"construction-of-a-metric-on-the-antitangent-bundle","status":"publish","type":"post","link":"http:\/\/blogs.scienceforums.net\/ajb\/2020\/01\/28\/construction-of-a-metric-on-the-antitangent-bundle\/","title":{"rendered":"Construction of a metric on the antitangent bundle"},"content":{"rendered":"<table border=\"0\">\n<tbody>\n<tr>\n<td><img decoding=\"async\" src=\"http:\/\/farm1.static.flickr.com\/158\/358365339_5c884a527b_m.jpg\" alt=\"board\" width=\"1500\" \/><\/td>\n<td style=\"vertical-align: top\">In a  short preprint <a href=\"https:\/\/arxiv.org\/abs\/2001.09724\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\nThe super-Sasaki metric on the antitangent bundle<\/a>, I explicitly show how to lift a Riemannian metric and an almost symplectic two-form on a manifold \\(M\\) to a Riemannian metric on the antitangent bundle \\(\\Pi T M\\), which is, of course, a supermanifold.   <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>This example was first  given in <a href=\"https:\/\/arxiv.org\/abs\/2001.05701\" target=\"_blank\" rel=\"noopener noreferrer\"><br \/>\nModular Classes of Q-Manifolds, Part II: Riemannian Structures &amp; Odd Killing Vectors Fields<\/a>, but in  <a href=\"https:\/\/arxiv.org\/abs\/2001.09724\" target=\"_blank\" rel=\"noopener noreferrer\"> The super-Sasaki metric on the antitangent bundle<\/a> I give more details and deduce some direct results.<\/p>\n<p>In particular, I compare the construction with that of the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Sasaki_metric\" rel=\"noopener\" target=\"_blank\">Sasaki metric<\/a> [1] on the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Tangent_bundle\" rel=\"noopener\" target=\"_blank\">tangent bundle<\/a> of a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Riemannian_manifold\" rel=\"noopener\" target=\"_blank\">Riemannian manifold<\/a>. Indeed the construction that I give is really the natural analog of Sasaki&#8217;s construction to the setting of <a href=\"https:\/\/en.wikipedia.org\/wiki\/Supermanifold#Examples\" rel=\"noopener\" target=\"_blank\">antitangent<\/a> (aka shifted tangent or odd) bundles. Due to the anticommuting nature of the fibre coordinates on \\(\\Pi T M\\), it is clear that directly lifting the metric will not work. One requires an antisymmetric component to the construction and this is provided for by an <a href=\"https:\/\/en.wikipedia.org\/wiki\/Almost_symplectic_manifold\" rel=\"noopener\" target=\"_blank\">almost symplectic structure<\/a>, i.e., a non-degenerate two form that is not necessarily <a href=\"https:\/\/en.wikipedia.org\/wiki\/Closed_and_exact_differential_forms\" rel=\"noopener\" target=\"_blank\">closed<\/a>.  <\/p>\n<p>It is well-known that <a href=\"https:\/\/en.wikipedia.org\/wiki\/Differential_form\" rel=\"noopener\" target=\"_blank\">differential forms<\/a> on a manifold \\(M\\) are functions on the antitangent bundle \\(\\Pi T M\\). Furthermore, the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Exterior_derivative\" rel=\"noopener\" target=\"_blank\">de Rham differential<\/a>, the<a href=\"https:\/\/en.wikipedia.org\/wiki\/Interior_product\" rel=\"noopener\" target=\"_blank\"> interior product<\/a> and the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Lie_derivative#The_Lie_derivative_of_a_differential_form\" rel=\"noopener\" target=\"_blank\">Lie derivative<\/a> can all be realised as <a href=\"https:\/\/en.wikipedia.org\/wiki\/Vector_field\" rel=\"noopener\" target=\"_blank\">vector fields<\/a> on the antitangent bundle.  In the short preprint, I examine the super-Sasaki metric on these vector fields.  We get some interesting formula in this way that related the &#8216;super-picture&#8217; with the more classical framework of the underlying Riemannian metric and differential forms.  <\/p>\n<p>It is worth noting that the classical Sasaki metric plays a role in <a href=\"https:\/\/en.wikipedia.org\/wiki\/Geometric_mechanics\" rel=\"noopener\" target=\"_blank\">geometric mechanics<\/a>. One can equip the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Configuration_space_(physics)\" rel=\"noopener\" target=\"_blank\">configuration space<\/a> of a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Lagrangian_mechanics\" rel=\"noopener\" target=\"_blank\">Lagrangian system<\/a> with the Jacobi metric and then, in turn, the tangent bundle of the configuration space naturally comes equipped with the associated Sasaki metric.  Trajectories can then be understood as <a href=\"https:\/\/en.wikipedia.org\/wiki\/Geodesic\" rel=\"noopener\" target=\"_blank\">geodesics<\/a> on the configuration space itself or as geodesic on the tangent bundle of the configuration space.  This makes me wonder if the construction of the super-Sasaki metric can play some role in supermechanics. <\/p>\n<p><b>References<\/b><br \/>\n[1] Sasaki, S., On the differential geometry of tangent bundles of Riemannian manifolds <em>Tohoku Math. J. (2)<\/em>  10 (1958),338-354.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In a short preprint The super-Sasaki metric on the antitangent bundle, I explicitly show how to lift a Riemannian metric and an almost symplectic two-form on a manifold \\(M\\) to a Riemannian metric on the antitangent bundle \\(\\Pi T M\\), which is, of course, a supermanifold. This example was first given in Modular Classes of &hellip; <a href=\"http:\/\/blogs.scienceforums.net\/ajb\/2020\/01\/28\/construction-of-a-metric-on-the-antitangent-bundle\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Construction of a metric on the antitangent bundle<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20,13],"tags":[],"class_list":["post-5546","post","type-post","status-publish","format-standard","hentry","category-post-doc-luxembourg","category-research-work"],"_links":{"self":[{"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/posts\/5546","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/comments?post=5546"}],"version-history":[{"count":20,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/posts\/5546\/revisions"}],"predecessor-version":[{"id":5566,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/posts\/5546\/revisions\/5566"}],"wp:attachment":[{"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/media?parent=5546"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/categories?post=5546"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/ajb\/wp-json\/wp\/v2\/tags?post=5546"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}