A dynamical interpretation of the profile curve of cmc Twizzlers surfaces

Abstract

It is known that for any non-zero $M in (-1/4,infty)$, if we roll the conic {(x,y): 4 x^2-y^2/M}=1} on a line in a plane, and then we rotate about this line the trace of a focus, then we obtain a surface of revolution D(M) with mean curvature 1. If M<=0, D(M) is embedded and it is called unduloid, if M>0, D(M) is not embedded and it is called nodoid. These surfaces are called Delaunays and they are foliated by circles. The trace of the focus in the construction above is called the profile curve of the Delaunay and it is transversal to the circles. Another well known family of constant mean curvature surfaces are the Twizzlers, they are foliated by helices and we can naturally define a profile curve which is transversal to the helices. To make the presentation in this abstract easier, we will be only considering Twizzlers with mean curvature 1. In this paper we will prove that if we roll the profile curve of a Twizzler on a line in a plane and, simultaneously, we move the points in the line at the same speed, so that the rolling motion of the profile curve looks like if it were placed on a treadmill, then, the trace made by the origin of the profile curve is one of the closed heart-shaped curves HS(M,w)={(x,y) : x^2+y^2+y/(1+w^2 x^2)=M} for some M>-1/4 and w>0. Using this dynamical interpretation we will prove several properties for Twizzlers