Construction of equilibrium states revisited
Changguang Dong, Qiujie Qiao
TL;DR
This work develops an explicit geometric construction for $\mathcal{F}$-equilibrium states in a broad class of expanding foliations arising from partially and nonuniformly hyperbolic diffeomorphisms. By introducing unstable entropy and unstable pressure along expanding foliations, the authors prove an abstract criterion under conditions (C1)–(C3) that yields equilibrium states as accumulation points of leafwise, weighted volume pushforwards. The criterion applies to exponential mixing systems, Katok maps, and almost Anosov diffeomorphisms, providing concrete existence results and illuminating how leafwise dynamics determine global thermodynamic behavior. These results extend prior geometric methods beyond Lyapunov stability and offer new avenues for explicit equilibrium-state constructions in nonuniformly hyperbolic settings with transverse growth.
Abstract
In [52], Parmenter and Pollicott establish an abstract criterion that gives a geometric construction of equilibrium states for a class of partially hyperbolic systems. We refine their criterion to cover a much broader class of diffeomorphisms, which include certain diffeomorphisms with exponential mixing property (with respect to volume), Katok maps and ``almost Anosov'' diffeomorphisms. As a special case, we obtain a construction of equilibrium states for ergodic partially hyperbolic affine maps/flows on homogeneous spaces, without any restrictions on the orbit growth along center directions.
