FIG. 3.

Schematic of the entropic tension ensemble. The thermal reservoir (left) at a finite temperature T has an actual area $\mathcal{A}-\Delta \mathcal{A}$ and a projected area ${\mathcal{A}}_p$, while the deformed domain-matrix system (right) is at T = 0. The small pipe represents a perfect thermal insulator that permits the flow of lipid from one region to the other, where the total amount of lipid in the ensemble is conserved, resulting in equal tension in both regions.