Classification Of Minimal Surfaces Research Articles

The Schwarzian Derivative and the Degree of a Classical Minimal Surface

Using the Schwarzian derivative we construct a sequence ( P l ) l ⩾ 2 of meromorphic differentials on every non-flat oriented minimal surface in Euclidean 3-space. The differentials ( P l ) l ⩾ 2 are invariant under all deformations of the surface arising via the Weierstrass representation and depend on the induced metric and its derivatives only. A minimal surface is said to have degree n if its n-th differential is a polynomial expression in the differentials of lower degree. We observe that several well-known minimal surfaces have small degree, including Enneper’s surface, the helicoid/catenoid and the Scherk—as well as the Schwarz family. Furthermore, it is shown that locally and away from umbilic points every minimal surface can be approximated by a sequence of minimal surfaces of increasing degree.

Multi-entropy at low Renyi index in 2d CFTs

For a static time slice of AdS_33 we describe a particular class of minimal surfaces which form trivalent networks of geodesics. Through geometric arguments we provide evidence that these surfaces describe a measure of multipartite entanglement. By relating these surfaces to Ryu-Takayanagi surfaces it can be shown that this multipartite contribution is related to the angles of intersection of the bulk geodesics. A proposed boundary dual [Phys. Rev. D 106, 126001 (2022), J. High Energy Phys. 08, 202 (2023), J. High Energy Phys. 05, 008 (2023)], the multi-entropy, generalizes replica trick calculations involving twist operators by considering monodromies with finite group symmetry beyond the cyclic group used for the computation of entanglement entropy. We make progress by providing explicit calculations of Renyi multi-entropy in two dimensional CFTs and geometric descriptions of the replica surfaces for several cases with low genus. We also explore aspects of the free fermion and free scalar CFTs. For the free fermion CFT we examine subtleties in the definition of the twist operators used for the calculation of Renyi multi-entropy. In particular the standard bosonization procedure used for the calculation of the usual entanglement entropy fails and a different treatment is required.

A Weierstrass Representation Formula for Discrete Harmonic Surfaces

A discrete harmonic surface is a trivalent graph which satisfies the balancing condition in the 3-dimensional Euclidean space and achieves energy minimizing under local deformations. Given a topological trivalent graph, a holomorphic function, and an associated discrete holomorphic quadratic form, a version of the Weierstrass representation formula for discrete harmonic surfaces in the 3-dimensional Euclidean space is proposed. By using the formula, a smooth converging sequence of discrete harmonic surfaces is constructed, and its limit is a classical minimal surface defined with the same holomorphic data. As an application, we have a discrete approximation of the Enneper surface.

Minimal surfaces and the new main inequality

We establish the new main inequality as a minimizing criterion for minimal maps into products of \(\mathbb{R}\)-trees, and the infinitesimal new main inequality as a stability criterion for minimal maps to \(\mathbb{R}^n\). Along the way, we develop a new perspective on destabilizing minimal surfaces in \(\mathbb{R}^n\), and as a consequence we reprove the instability of some classical minimal surfaces; for example, the Enneper surface.

Some perspectives on (non)local phase transitions and minimal surfaces

We present here some classical and modern results about phase transitions and minimal surfaces, which are quite intertwined topics. We start from scratch, revisiting the theory of phase transitions as put forth by Lev Landau. Then, we relate the short-range phase transitions to the classical minimal surfaces, whose basic regularity theory is presented, also in connection with a celebrated conjecture by Ennio De Giorgi. With this, we explore the recently developed subject of long-range phase transitions and relate its genuinely nonlocal regime to the analysis of fractional minimal surfaces.

Generalized Henneberg Stable Minimal Surfaces

We generalize the classical Henneberg minimal surface by giving an infinite family of complete, finitely branched, non-orientable, stable minimal surfaces in mathbb {R}^3. These surfaces can be grouped into subfamilies depending on a positive integer (called the complexity), which essentially measures the number of branch points. The classical Henneberg surface H_1 is characterized as the unique example in the subfamily of the simplest complexity m=1, while for mge 2 multiparameter families are given. The isometry group of the most symmetric example H_m with a given complexity min mathbb {N} is either isomorphic to the dihedral isometry group D_{2m+2} (if m is odd) or to D_{m+1}times mathbb {Z}_2 (if m is even). Furthermore, for m even H_m is the unique solution to the Björling problem for a hypocycloid of m+1 cusps (if m is even), while for m odd the conjugate minimal surface H_m^* to H_m is the unique solution to the Björling problem for a hypocycloid of 2m+2 cusps.

The Second Variation for Null-Torsion Holomorphic Curves in the 6-Sphere

In the round 6-sphere, null-torsion holomorphic curves are fundamental examples of minimal surfaces. This class of minimal surfaces is quite rich: By a theorem of Bryant, extended by Rowland, every closed Riemann surface may be conformally embedded in the round 6-sphere as a null-torsion holomorphic curve. In this work, we study the second variation of area for compact null-torsion holomorphic curves \(\Sigma \) of genus g and area \(4\pi d\), focusing on the spectrum of the Jacobi operator. We show that if \(g \le 6\), then the multiplicity of the lowest eigenvalue \(\lambda _1 = -2\) is equal to 4d. Moreover, for any genus, we show that the nullity is at least \(2d + 2 - 2g\). These results are likely to have implications for the deformation theory of asymptotically conical associative 3-folds in \({\mathbb {R}}^7\), as studied by Lotay.

Minimal surfaces on mirror-symmetric frames: a fluid dynamics analogy

Chaplygin’s hodograph method of classical fluid mechanics is applied to explicitly solve the Plateau problem of finding minimal surfaces. The minimal surfaces are formed between two mirror-symmetric polygonal frames having a common axis of symmetry. Two classes of minimal surfaces are found: the class of regular surfaces continuously connecting the supporting frames forming a tube with complex shape; and the class of singular surfaces which have a partitioning film closing the tube in between. As an illustration of the general solution, minimal surfaces supported by triangular frames are fully described. The theory is experimentally validated using soap films. The general solution is compared with the known particular solutions obtained by the Weierstrass inverse method.

Minimizing cones associated with isoparametric foliations

Associated with isoparametric foliations of unit spheres, there are two classes of minimal surfaces − minimal isoparametric hypersurfaces and focal submanifolds. By virtue of their rich structures, we find new series of minimizing cones. They are cones over focal submanifolds and cones over suitable products among these two classes. Except in low dimensions, all such cones are shown minimizing.

The $$C_{m r}^{\kappa h}$$ minimal surfaces

In this work is presented a family that generalizes Bour’s, Enneper’s, Richmond’s and Henneberg’s minimal surfaces. First of all is introduced a generalization for the well-known Bour’s family $$B_m$$ by including a new index r, determining a new bigger family $$B_{m r}$$ , which includes Bour’s, Enneper’s and Richmond’s families of minimal surfaces. After that, realizing some similarities between the Enneper–Weierstrass data of the Henneberg’s minimal surface and the $$B_{m r}$$ family, it is established a new family of minimal surfaces $$H_{m r}$$ that includes the classical Henneberg minimal surface. Finally, it is presented a bigger family $$C_ {m r}^{\kappa h}, \ m,r \in {\mathbb {R}}, \ \kappa \in {\mathbb {C}}$$ which includes as particular cases $$B_{m r}$$ and $$H_{m r}$$ families. Consequently, catenoid, helicoid, Enneper’s minimal surfaces, Bour’s minimal surfaces, Richmond’s minimal surfaces and Henneberg’s minimal surfaces are just some elements of the set of $$C_ {m r}^{\kappa h}$$ surfaces.

Quantitative flatness results and $BV$-estimates for stable nonlocal minimal surfaces

We establish quantitative properties of minimizers and stable sets for nonlocal interaction functionals, including the $s$-fractional perimeter as a particular case. On the one hand, we establish universal $BV$-estimates in every dimension $n \geqslant 2$ for stable sets. Namely, we prove that any stable set in $B_1$ has finite classical perimeter in $B_{1/2}$, with a universal bound. This nonlocal result is new even in the case of $s$-perimeters and its local counterpart (for classical stable minimal surfaces) was known only for simply connected two-dimensional surfaces immersed in $\mathbb{R}^3$. On the other hand, we prove quantitative flatness estimates for minimizers and stable sets in low dimensions $n = 2, 3$. More precisely, we show that a stable set in $B_R$, with $R$ large, is very close in measure to being a half space in $B_1$ – with a quantitative estimate on the measure of the symmetric difference. As a byproduct, we obtain new classification results for stable sets in the whole plane.

Structure theorems for singular minimal laminations

Abstract We apply the local removable singularity theorem for minimal laminations [W. H. Meeks III, J. Pérez and A. Ros, Local removable singularity theorems for minimal laminations, J. Differential Geom. 103 (2016), no. 2, 319–362] and the local picture theorem on the scale of topology [W. H. Meeks III, J. Pérez and A. Ros, The local picture theorem on the scale of topology, J. Differential Geom. 109 (2018), no. 3, 509–565] to obtain two descriptive results for certain possibly singular minimal laminations of ℝ 3 {\mathbb{R}^{3}} . These two global structure theorems will be applied in [W. H. Meeks III, J. Pérez and A. Ros, Bounds on the topology and index of classical minimal surfaces, preprint 2016] to obtain bounds on the index and the number of ends of complete, embedded minimal surfaces of fixed genus and finite topology in ℝ 3 {\mathbb{R}^{3}} , and in [W. H. Meeks III, J. Pérez and A. Ros, The embedded Calabi–Yau conjectures for finite genus, preprint 2018] to prove that a complete, embedded minimal surface in ℝ 3 {\mathbb{R}^{3}} with finite genus and a countable number of ends is proper.

Discrete projective minimal surfaces

We propose a natural discretisation scheme for classical projective minimal surfaces. We follow the classical geometric characterisation and classification of projective minimal surfaces and introduce at each step canonical discrete models of the associated geometric notions and objects. Thus, we introduce discrete analogues of classical Lie quadrics and their envelopes and classify discrete projective minimal surfaces according to the cardinality of the class of envelopes. This leads to discrete versions of Godeaux-Rozet, Demoulin and Tzitzéica surfaces. The latter class of surfaces requires the introduction of certain discrete line congruences which may also be employed in the classification of discrete projective minimal surfaces. The classification scheme is based on the notion of discrete surfaces which are in asymptotic correspondence. In this context, we set down a discrete analogue of a classical theorem which states that an envelope (of the Lie quadrics) of a surface is in asymptotic correspondence with the surface if and only if the surface is either projective minimal or a Q surface. Accordingly, we present a geometric definition of discrete Q surfaces and their relatives, namely discrete counterparts of classical semi-Q, complex, doubly Q and doubly complex surfaces.

Three-Dimensional Graph Surfaces on Five-Dimensional Carnot–Carathéodory Spaces

We study the class of codimension 2 graph surfaces over some three-dimensional Lie groups and establish some analogs of the differential properties of the corresponding graph mappings. Moreover, we derive the area formula and describe the classes of minimal surfaces of codimension 1 and 2.

Algebraic Aspects of the Supersymmetric Minimal Surface Equation

In this paper, a supersymmetric extension of the minimal surface equation is formulated. Based on this formulation, a Lie superalgebra of infinitesimal symmetries of this equation is determined. A classification of the one-dimensional subalgebras is performed, which results in a list of 143 conjugacy classes with respect to action by the supergroup generated by the Lie superalgebra. The symmetry reduction method is used to obtain invariant solutions of the supersymmetric minimal surface equation. The classical minimal surface equation is also examined and its group-theoretical properties are compared with those of the supersymmetric version.

Rigidity Theorems of Minimal Surfaces Foliated by Similar Planar Curves

Catenoids, Riemann’s minimal surfaces, and Scherk’s surfaces (doubly periodic minimal surfaces) are classical minimal surfaces in \(\mathbb {R}^3\). The catenoid and Riemann’s minimal surface can be foliated by circles with different radii. Because the Scherk’s surface is represented by the graph of \(z(x,y)=\log \cos x-\log \cos y\), it can be foliated by curves congruent to the graph of \(z=\log {\cos x}\). In this study, we consider surfaces foliated by similar planar curves. When the surface is minimal \((H=0)\) and foliated by homothetic curves without translations, the surface is either a plane or a catenoid. In addition, a minimal surface foliated by parallel ellipses including circles is either a catenoid or a Riemann’s minimal surface. When the surface foliated by ellipses without translations has constant mean curvature, the surface is either a sphere or one of Delaunay surfaces. Finally, we prove that a nonplanar minimal surface foliated by congruent planar curves with only translations on each plane is a generalized Scherk’s surface.

Geodesics in minimal surfaces

Abstract—In this paper, we consider connected minimal surfaces in R3 with isothermal coordinates and with a family of geodesic coordinates curves, these surfaces will be called GICM-surfaces. We give a classification of the GICM-surfaces. This class of minimal surfaces includes the catenoid, the helicoid and Enneper’s surface. Also, we show that one family of this class of minimal surfaces has at least one closed geodesic and one 1-periodic family of this class has finite total curvature. As application we show other characterization of catenoid and helicoid. Finally, we show that the class of GICM-surfaces coincides with the class of minimal surfaces whose the geodesic curvature k g 1 and k g 2 of the coordinates curves satisfy αk g 1 + βk g 2 = 0, α, β ∈ R.

Characterizing Classical Minimal Surfaces Via the Entropy Differential

We introduce on any smooth oriented minimal surface in Euclidean $3$-space a meromorphic quadratic differential, $P$, which we call the entropy differential. This differential arises naturally in a number of different contexts. Of particular interest is the realization of its real part as a conservation law for a natural geometric functional -- which is, essentially, the entropy of the Gauss curvature. We characterize several classical surfaces -- including Enneper's surface, the catenoid and the helicoid -- in terms of $P$. As an application, we prove a novel curvature estimate for embedded minimal surfaces with small entropy differential and an associated compactness theorem.

A minimal surface criterion for graph partitioning

We consider a geometric approach to graph partitioning based on the graph Beltrami energy, a discrete version of a functional that appears in classical minimal surface problems. More specifically, the optimality criterion is given by the sum of the minimal Beltrami energies of the partition components. Since the Beltrami energy interpolates between the Total Variation and Dirichlet energies, various results for optimal partitions for these two energies can be recovered. We adapt primal-dual convex optimization methods to solve for the minimal Beltrami energy for each component of a given partition. A rearrangement algorithm is proposed to find the graph partition to minimize a relaxed version of the objective. The method is applied to several clustering problems on graphs constructed from manifold discretizations, synthetic data, the MNIST handwritten digit dataset, and image segmentation. The model has a semisupervised extension and provides a natural representative for the clusters as well.

Deformations of constant mean curvature surfaces preserving symmetries and the Hopf differential

We define certain deformations between minimal and non-minimal constant mean curvature (CMC) surfaces in Euclidean space $E^3$ which preserve the Hopf differential. We prove that, given a CMC $H$ surface $f$, either minimal or not, and a fixed basepoint $z_0$ on this surface, there is a naturally defined family $f_h$, for all real $h$, of CMC $h$ surfaces that are tangent to $f$ at $z_0$, and which have the same Hopf differential. Given the classical Weierstrass data for a minimal surface, we give an explicit formula for the generalized Weierstrass data for the non-minimal surfaces $f_h$, and vice versa. As an application, we use this to give a well-defined dressing action on the class of minimal surfaces. In addition, we show that symmetries of certain types associated with the basepoint are preserved under the deformation, and this gives a canonical choice of basepoint for surfaces with symmetries. We use this to define new examples of non-minimal CMC surfaces naturally associated to known minimal surfaces with symmetries.