Figure 2
Illustration: Alan Stonebraker

Figure 2: (top) The model from Vojta, Kotabage, and Hoyos can describe what happens when an ultrathin metallic wire is cooled to the verge of turning into a superconductor. Superconducting puddles (orange) are connected to their neighbors through “weak links“ in a metallic environment. Because the superconductivity in each puddle is described by a complex order parameter, the puddles can be modeled as planar magnetons, with a magnitude and direction that correspond to the amplitude and phase of the order parameter, respectively. The metallic environment induces dissipation and dampens fluctuations of the order parameter. (bottom) Restricting ourselves to the language of magnetons, we sketch out how the details on small length scales become unimportant to the description of the system. Grain 4 fluctuates so much that its effective magnetic moment is destroyed. Next, grains 2 and 3 unite because of the strong magnetic coupling between them, and point in the same direction, but they too can diminish due to strong resulting fluctuations. Finally, grains 1 and 5 unite due to a resulting coupling between them.