{"id":717,"date":"2026-09-23T14:55:15","date_gmt":"2026-09-23T17:55:15","guid":{"rendered":"https:\/\/www.ccen.ufpb.br\/ppgf\/?p=717"},"modified":"2026-09-24T09:39:35","modified_gmt":"2026-09-24T12:39:35","slug":"coloquio-do-ppgf-25-de-setembro-de-2026","status":"publish","type":"post","link":"https:\/\/www.ccen.ufpb.br\/ppgf\/ciclo-de-coloquios\/coloquio-do-ppgf-25-de-setembro-de-2026\/","title":{"rendered":"Col\u00f3quio do PPGF: 25 de setembro de 2026"},"content":{"rendered":"\n

Col\u00f3quio #04 2026.2<\/div><\/h2>\n\n\n\n

O Programa de P\u00f3s-Gradua\u00e7\u00e3o em F\u00edsica (PPGF) realizar\u00e1, na pr\u00f3xima sexta-feira, 25 de setembro de 2026<\/strong>, mais uma edi\u00e7\u00e3o de seu col\u00f3quio.<\/p>\n\n\n\n

Nesta semana, o encontro ser\u00e1 dividido em tr\u00eas apresenta\u00e7\u00f5es<\/strong>, com 20 minutos destinados a cada exposi\u00e7\u00e3o<\/strong>. O col\u00f3quio contar\u00e1 com a participa\u00e7\u00e3o de pesquisadores do M\u00e9xico<\/strong>, que est\u00e3o em visita acad\u00eamica \u00e0 Universidade Federal da Para\u00edba (UFPB).<\/p>\n\n\n\n

Sexta-feira, 25 de setembro de 2026, \u00e0s 14h, no Audit\u00f3rio 2 do Pr\u00e9dio da P\u00f3s-Gradua\u00e7\u00e3o em F\u00edsica\/CCEN.<\/strong><\/p>\n\n\n\n

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Localization of a Weyl invariant action into a Principal Bundle<\/strong><\/p>\n\n\n\n

Dr. Jos\u00e9 Carlos Zamarripa Rodr\u00edguez <\/p>\n\n\n\n

Departamento de matem\u00e1ticas <\/p>\n\n\n\n

Centro Universitario de Ciencias Exactas e Ingenier\u00eda <\/p>\n\n\n\n

Universidad de Guadalajara, M\u00e9xico<\/p>\n\n\n\n

<\/p>\n\n\n\n

This talk presents a geometric construction of a principal bundle (P) as an extension of Weyl-Integrable geometry. Starting from a base manifold (M) and the introduction of an additional fiber, we define the principal-bundle connection and the associated decomposition of the tangent space into horizontal and vertical subspaces. This construction provides a framework for relating the geometry of the total space to the underlying Weyl-Integrable structure of the base manifold (M). Finally, the divergence problem emerging from this formulation is briefly examined, together with two possible approaches to addressing it.<\/p>\n<\/div><\/div>\n\n\n\n

<\/p>\n\n\n\n

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Gravity from Invariant Weyl-Integrable space-time (IWIST)<\/strong><\/p>\n\n\n\n

Dr. Jos\u00e9 Edgar Madriz Aguilar <\/p>\n\n\n\n

Departamento de Matem\u00e1ticas<\/p>\n\n\n\n

Centro Universitario de Ciencias Exactas e Ingenier\u00edas <\/p>\n\n\n\n

Universidad de Guadalajara, M\u00e9xico.<\/p>\n\n\n\n

<\/p>\n\n\n\n

In this talk I present a geometrically motivated formulation of gravity in an invariant Weyl-Integrable space-time (IWIST), in which the background geometry is not imposed a priori but is dynamically determined through the Palatini variational principle. For a scalar field non-minimally coupled to gravity action, the resulting compatibility condition defines a Weyl-Integrable geometry which is preserved by a local Weyl transformation of the metric and the geometrical scalar field. We construct an action invariant under both diffeomorphisms and Weyl transformations and introduce a Weyl-covariant variational procedure based on an invariant extension of the divergence theorem. The corresponding field equations are obtained for the metric, the Weyl scalar, and the Weyl gauge field. We further formulate the theory in the Einstein–Riemann frame, where the effective metric is Riemannian and the scalar field is reinterpreted as a physical degree of freedom of geometric origin. Finally, we propose a geometrical mechanism for a explicit breaking of Weyl symmetry by introducing a coupling between the Weyl gauge field and a current constructed from the scalar sector. The resulting theory remains diffeomorphism covariant while departing from local Weyl invariance. The Einstein-Riemann representation of the broken theory contains an additional generally covariant interaction, making the Weyl-invariant model a particular limit of a more general gravitational theory.<\/p>\n<\/div><\/div>\n\n\n\n

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A novel pre-inflationary model in view of the lack of angular correlation in the CMB<\/strong><\/p>\n\n\n\n

Alfonso Bernal Tirado <\/p>\n\n\n\n

Departamento de Ciencias exactas y Naturales <\/p>\n\n\n\n

Centro Universitario de los Valles <\/p>\n\n\n\n

Universidad de Guadalajara, M\u00e9xico.<\/p>\n\n\n\n

<\/p>\n\n\n\n

In this presentation, we propose a new unified pre-inflationary\u2013inflationary model of theUniverse motivated by recent Planck satellite observations. The Planck mission reported a lack of correlation in the two-point angular correlation function at large angular separations, a feature associated with a cutoff in the primordial power spectrum and a delayed onset of inflation. With the aim of addressing these issues, we propose a model in which the pre-inflationary era begins at the Planck time and is followed by an inflationary period. During this first phase, the Universe undergoes a decelerated expansion that transitions into na accelerated one, ending in a de Sitter stage at which inflation begins. Throughout this pre-inflationary phase, the horizon grows while causally disconnected modes of the pre-inflaton field remain causally disconnected, naturally explaining the lack of angular correlation observed in the CMB by Planck.<\/p>\n<\/div><\/div>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Col\u00f3quio #04 2026.2 O Programa de P\u00f3s-Gradua\u00e7\u00e3o em F\u00edsica (PPGF) realizar\u00e1, na pr\u00f3xima sexta-feira, 25 […]<\/p>\n","protected":false},"author":682,"featured_media":730,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-717","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ciclo-de-coloquios"],"_links":{"self":[{"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/posts\/717","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/users\/682"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/comments?post=717"}],"version-history":[{"count":5,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/posts\/717\/revisions"}],"predecessor-version":[{"id":736,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/posts\/717\/revisions\/736"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/media\/730"}],"wp:attachment":[{"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/media?parent=717"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/categories?post=717"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ccen.ufpb.br\/ppgf\/wp-json\/wp\/v2\/tags?post=717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}