Persistent Non-statistical Dynamics in One-Dimensional Maps

We study a class \(\widehat{{\mathfrak {F}}}\) of one-dimensional full branch maps introduced in Coates et al. (Commun Math Phys 402(2):1845–1878, 2023), admitting two indifferent fixed points as well as critical points and/or singularities with unbounded derivative. We show that \(\widehat{{\mathfrak {F}}}\) can be partitioned into 3 pairwise disjoint subfamilies \(\widehat{{\mathfrak {F}}} = {\mathfrak {F}} \cup {\mathfrak {F}}_\pm \cup {\mathfrak {F}}_*\) such that all \(g \in {\mathfrak {F}}\) have a unique physical measure equivalent to Lebesgue, all \(g \in {\mathfrak {F}}_{\pm }\) have a physical measure which is a Dirac-\(\delta \) measure on one of the (repelling) fixed points, and all \(g \in {\mathfrak {F}}_{*}\) are non-statistical and in particular have no physical measure. Moreover we show that these subfamilies are intermingled: they can all be approximated by maps in the other subfamilies in natural topologies.