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Motivated by geometry processing for surfaces with non-trivial topology, we study discrete harmonic maps between closed surfaces of genus at least two. Harmonic maps provide a natural framework for comparing surfaces by minimizing…

Numerical Analysis · Mathematics 2025-09-03 Zhipeng Zhu , Wai Yeung Lam , Lok Ming Lui

The first result in this study is a non-existence theorem for $\alpha-$harmonic mappings. Additionally, a direct connection between the $\alpha-$ harmonic and harmonic maps is made possible via conformal deformation. Second, the instability…

Differential Geometry · Mathematics 2022-08-26 Seyed Mehdi Kazemi Torbaghan , Keyvan Salehi

In this paper, we formulate and prove a general compactness theorem for harmonic maps using Deligne-Mumford moduli space and families of curves. The main theorem shows that given a sequence of harmonic maps over a sequence of complex…

Differential Geometry · Mathematics 2024-06-07 Woongbae Park

Critical points of approximations of the Dirichlet energy \`{a} la Sacks-Uhlenbeck are known to converge to harmonic maps in a suitable sense. However, we show that not every harmonic map can be approximated by critical points of such…

Differential Geometry · Mathematics 2015-08-06 Tobias Lamm , Andrea Malchiodi , Mario Micallef

Existence and stability of Dirac points in the dispersion relation of operators periodic with respect to the hexagonal lattice is investigated for different sets of additional symmetries. The following symmetries are considered: rotation by…

Mathematical Physics · Physics 2016-12-13 Gregory Berkolaiko , Andrew Comech

In this paper we consider approximations introduced by Sacks-Uhlenbeck of the harmonic energy for maps from $S^2$ into $S^2$. We continue the analysis in [6] about limits of $\alpha$-harmonic maps with uniformly bounded energy. Using a…

Differential Geometry · Mathematics 2021-05-19 Tobias Lamm , Andrea Malchiodi , Mario Micallef

We study biharmonic maps between conformally compact manifolds, a large class of complete manifolds with bounded geometry, asymptotically negative curvature, and smooth compactification. These metrics provide a far-reaching generalization…

Differential Geometry · Mathematics 2026-01-14 Marco Usula

We introduce a functional that couples the nonlinear sigma model with a spinor field: $L=\int_M[|d\phi|^2+(\psi,\D\psi)]$. In two dimensions, it is conformally invariant. The critical points of this functional are called Dirac-harmonic…

Differential Geometry · Mathematics 2007-05-23 Qun Chen , Juergen Jost , Jiayu Li , Guofang Wang

Let $\varphi\in C^0 \cap W^{1,2}(\Sigma, X)$ where $\Sigma$ is a compact Riemann surface, $X$ is a compact locally CAT(1) space, and $W^{1,2}(\Sigma,X)$ is defined as in Korevaar-Schoen. We use the technique of harmonic replacement to prove…

Differential Geometry · Mathematics 2017-01-11 Christine Breiner , Ailana Fraser , Lan-Hsuan Huang , Chikako Mese , Pam Sargent , Yingying Zhang

Harmonic maps are nonlinear extensions of harmonic functions. They are critical points of natural energy functionals between Riemannian manifolds. Such type of problems appear in Physics, Geometry of Finance and the study of regularity and…

Analysis of PDEs · Mathematics 2023-03-27 Wei Wang

For a homotopy class $[u]$ of maps between a closed Riemannian manifold $M$ and a general manifold $N$, we want to find a Dirac-harmonic map with the map component in the given homotopy class. Most known results require the index to be…

Differential Geometry · Mathematics 2024-12-24 Jürgen Jost , Linlin Sun , Jingyong Zhu

We study several geometric and analytic aspects of Dirac-harmonic maps with curvature term from closed Riemannian surfaces.

Differential Geometry · Mathematics 2015-12-01 Volker Branding

We study biharmonic maps between Riemannian manifolds with finite energy and finite bi-energy. We show that if the domain is complete and the target of non-positive curvature, then such a map is harmonic. We then give applications to…

Differential Geometry · Mathematics 2012-10-02 Nobumitsu Nakauchi , Hajime Urakawa , Sigmundur Gudmundsson

An existence result is shown for the asymptotic Dirichlet problem for harmonic maps from the product of the hyperbolic planes to the hyperbolic space, where the Dirichlet data is given on the distinguished boundary (the product of the…

Differential Geometry · Mathematics 2025-09-01 Kazuo Akutagawa , Yoshihiko Matsumoto

We relate the existence problem of harmonic maps into $S^2$ to the convex geometry of $S^2$. On one hand, this allows us to construct new examples of harmonic maps of degree 0 from compact surfaces of arbitrary genus into $S^2$. On the…

Differential Geometry · Mathematics 2019-11-05 Renan Assimos , Jürgen Jost

In 1981, Sacks and Uhlenbeck introduced their famous $\alpha$-energy as a way to approximate the Dirichlet energy and produce harmonic maps from surfaces into Riemannian manifolds. However, the second and third authors together with…

Differential Geometry · Mathematics 2022-06-01 Jasmin Hörter , Tobias Lamm , Mario Micallef

We prove that all harmonic maps from $\mathbb R^2$ to $\mathbb S^2$ with finite energy are nondegenerate. That is, for any harmonic map $u$ from $\mathbb R^2$ to $\mathbb S^2$ of degree $m$ (in $\mathbb Z$), all bounded kernel maps of the…

Analysis of PDEs · Mathematics 2018-06-12 Guoyuan Chen , Yong Liu , Juncheng Wei

In this paper we study an energy of maps between almost Hermitian manifolds for which pseudo-holomorphic maps are global minimizers. We derive its Euler-Lagrange equation, the $\bar{\partial}$-harmonic map equation, and show that it…

Differential Geometry · Mathematics 2015-08-07 Jess Boling

We consider the explicit asymptotic profile of massless Dirac fields on a Schwarzschild background. First, we prove for the spin $s=\pm \frac{1}{2}$ components of the Dirac field a uniform bound of a positive definite energy and an…

Analysis of PDEs · Mathematics 2022-02-10 Siyuan Ma , Lin Zhang

We discuss a method to construct Dirac-harmonic maps developed by J.~Jost, X.~Mo and M.~Zhu in J.~Jost, X.~Mo, M.~Zhu, \emph{Some explicit constructions of Dirac-harmonic maps}, J. Geom. Phys. \textbf{59} (2009), no. 11, 1512--1527.The…

Analysis of PDEs · Mathematics 2018-09-27 Nicolas Ginoux , Bernd Ammann