Ecuación de Helmholtz generalizada

In this paper we introduce the generalized Helmholtz equation and present explicit solutions to this generalized Helmholtz equation, these solutions depend on three holomorphic functions. As an application we present explicit solutions to the Helmholtz equation. We note that these solutions are not necessarily limited to certain domains of the complex plane C.En este artículo introducimos la ecuación de Helmholtz generalizada y presentamos soluciones explícitas para esta ecuación de Helmholtz generalizada, estas soluciones dependen de tres funciones holomorfas. Como aplicación presentamos soluciones explícitas para la ecuación de Helmholtz. Observamos que estas soluciones nonecesariamente estan limitadas a ciertos dominios del plano complejo C

Hipersuperficies con líneas de curvatura planas en espacios euclideanos

In this work, we present explicit parameterizations of hypersurfaces parameterized by lines of curvature with prescribed Gauss map and we characterize the hypersurfaces with planar curvature lines. As an applicationwe obtain a classification of isothermic surfaces with respect to the third fundamental form with two planar curvature lines. Also, we present a class of surfaces with one family of planar curvature lines and generalize these results to present classes of hypersurfaces with families of planar curvature lines.En este trabajo, presentamos parametrizaciones explícitas de hipersuperficies parametrizadas por líneas de curvatura con aplicación de Gauss prescrita y caracterizamos las hipersuperficies con líneas de curvatura planas. Como aplicación obtenemos una clasificación de superficies isotérmicas con respecto a la tercera forma fundamental con dos líneas de curvatura planas. También, presentamos una clase de superficiescon una familia de líneas de curvatura plana y generalizamos estos resultados para presentar clases de hipersuperficies con familias de líneas de curvatura planas.

Rotation of an atomic Bose-Einstein condensate with and without a quantized vortex

We theoretically examine the rotation of an atomic Bose-Einstein condensate in an elliptical trap, both in the absence and presence of a quantized vortex. Two methods of introducing the rotating potential are considered - adiabatically increasing the rotation frequency at fixed ellipticity, and adiabatically increasing the trap ellipticity at fixed rotation frequency. Extensive simulations of the Gross-Pitaevskii equation are employed to map out the points where the condensate becomes unstable and ultimately forms a vortex lattice. We highlight the key features of having a quantized vortex in the initial condensate. In particular, we find that the presence of the vortex causes the instabilities to shift to lower or higher rotation frequencies, depending on the direction of the vortex relative to the trap rotation.Comment: 15 pages, 8 figure

Superfícies bi-harmonicas de tipo gráfico em R3

In this work, we study biharmonic surfaces that are parameterized by biharmonic coordinate functions. We study a class of biharmonic surfaces called graph-type biharmonic surfaces. Also, we define a class of surfaces associated to two harmonic functions (FH2A-surfaces), these surfaces satisfy a relation between the Gaussian curvature, the projection of the Gauss map on a fixed plane and two harmonic functions. We show that a particular class of graph-type biharmonic surfaces are FH2A-surfaces. Finally, we classify the FH2A-surfaces of rotation.Neste artigo, estudamos superfícies bi-harmonicas que sao parametrizadas por funcoes coordenadas biharmonicas. Estudamos uma classe de superfícies bi-harmonicas, chamadas superficies bi-harmonicas de tipo gráfico. Tambem, definimos uma classe de superfícies associadas a duas funcoes harmonicas (FH2Asurfaces), essas superfícies satisfazem uma relacao entre a curvatura Gaussiana, a projecao da aplicacao de Gauss sobre um plano fixo e duas funcoes harmonicas. Mostramos que uma classe particular de superfícies bi-harmonicas de tipo gráfico sao FH2A-surfaces. Finalmente, classificamos as FH2A-surfaces de rotacao

Dynamics of two-component Bose-Einstein condensates in rotating traps

The dynamics of two-component Bose-Einstein condensates in rotating traps is investigated. In the Thomas-Fermi limit, equations of motion are derived showing multiple static solutions for a vortex free condensate. Dynamic stability analysis of these solutions and comparison with Truncated Wigner simulations enables us to identify the regimes for which vortex states will occur. In addition, our analysis predicts centre-of-mass oscillations that are induced by interspecies interactions and affect each component separately. For attractive interspecies interactions, these oscillations lead to a stable symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some rewording v7:fixed figure

Singular Riemannian Foliations, variational problems and Principles of Symmetric Criticalities

A singular foliation $\mathcal{F}$ on a complete Riemannian manifold $M$ is called Singular Riemannian foliation (SRF for short) if its leaves are locally equidistant, e.g., the partition of $M$ into orbits of an isometric action. In this paper, we investigate variational problems in compact Riemannian manifolds equipped with SRF with special properties, e.g. isoparametric foliations, SRF on fibers bundles with Sasaki metric, and orbit-like foliations. More precisely, we prove two results analogous to Palais' Principle of Symmetric Criticality, one is a general principle for $\mathcal{F}$ symmetric operators on the Hilbert space $W^{1,2}(M)$, the other one is for $\mathcal{F}$ symmetric integral operators on the Banach spaces $W^{1,p}(M)$. These results together with a $\mathcal{F}$ version of Rellich Kondrachov Hebey Vaugon Embedding Theorem allow us to circumvent difficulties with Sobolev's critical exponents when considering applications of Calculus of Variations to find solutions to PDEs. To exemplify this we prove the existence of weak solutions to a class of variational problems which includes $p$-Kirschoff problems.Comment: 54 page