Thermodynamical and spectral phase transitions for local diffeomorphisms on the circle
Thermodynamic formalism, Transfer Operator; Linear Response Formula; Large Deviation Principles; Multifractal Analysis.
It is known that all uniformly expanding dynamics have no phase transition with respect to H\"older continuous potentials. In this work we show that given a local diffeomorphism $f$ on the circle, that is neither a uniformly expanding dynamics nor invertible, the topological pressure function $\R \ni t \mapsto P_{top}(f,-t\log|Df|)$ is not analytical. In other words, $f$ has a thermodynamic phase transition with respect to geometric potential. Assuming that $f$ is transitive and that $Df$ is Hölder continuous, we show that there exists $t_0 \in (0,1]$ such that the transfer operator $\Lo_{f,-t\log|Df|}$ acting on the space of H\"older continuous functions, has the spectral gap property for all $t<t_0$ and has not the spectral gap property for all $t\geq t_0$. Similar results are also obtained when the transfer operator acts on the space of bounded variations functions and smooth functions. In particular, we show that in the transitive case $f$ has a unique thermodynamic phase transition and it occurs in $t_0$. In addition, if the loss of expansion of the dynamics occurs because of an indifferent fixed point or the dynamics admits an absolutely continuous invariant probability with positive Lyapunov exponent then $t_0=1$. As a consequence of thermodynamical and spectral phase transition, we obtain applications on multifractal analysis for the Lyapunov spectrum.