DOCUMENTA MATHEMATICA, Vol. 16 (2011), 133-175

Kengo Matsumoto

Ergodic Properties and KMS Conditions on $C^*$-Symbolic Dynamical Systems

A $C^*$-symbolic dynamical system $({\mathcal A}, \rho, \Sigma)$ consists of a unital $C^*$-algebra ${\mathcal A}$ and a finite family ${ \rho_\alpha }_{\alpha \in \Sigma}$ of endomorphisms $\rho_\alpha $ of ${\mathcal A}$ indexed by symbols $\alpha$ of $\Sigma$ satisfying some conditions. The endomorphisms $\rho_\alpha, \alpha \in \Sigma $ yield both a subshift $\Lambda_\rho$ and a $C^*$-algebra ${\mathcal O}_\rho$. We will study ergodic properties of the positive operator $lambda_\rho = \sum_{\alpha \in \Sigma}\rho_\alpha$ on ${\mathcal A}$. We will next introduce KMS conditions for continuous linear functionals on ${\mathcal O}_\rho$ under gauge action at inverse temperature taking its value in complex numbers. We will study relationships among the eigenvectors of $lambda_\rho$ in ${\mathcal A}^*$, the continuous linear functionals on ${\mathcal O}_\rho$ satisfying KMS conditions and the invariant measures on the associated one-sided shifts. We will finally present several examples of continuous linear functionals satisfying KMS conditions.

2010 Mathematics Subject Classification: Primary 46L55, 37B10; Secondary 37D35.

Keywords and Phrases: $C^*$-algebra, symbolic dynamics, subshift, ergodic, KMS condition, invariant measure.

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