Non-isometric pairs of Riemannian manifolds with the same Guillemin-Ruelle zeta function

In 1985, T. Sunada constructed a vast collection of non-isometric Laplace-isospectral pairs $(M_1,g_1)$, resp. $(M_2,g_2)$ of Riemannian manifolds. He further proves that the Ruelle zeta functions $Z_g(s):={\prod }_{\gamma }(1-e^{-sL(\gamma )}{)}^{-1}$ of $(M_1,g_1)$, resp. $(M_2,g_2)$ coincide, where $\{\gamma \}$ runs over the primitive closed geodesics of $(M,g)$ and $L(\gamma )$ is the length of $\gamma$. In this article, we use the method of intertwining operators on the unit cosphere bundle to prove that the same Sunada pairs have identical Guillemin-Ruelle dynamical L-functions $L_G(s)={\sum }_{\gamma \in \mathcal{G}}\frac{L_{\gamma }^{\mathrm{\#}}{e}^{-s{L}_{\gamma }}}{\mathrm{\mid }\det (I-{\mathbf{P}}_{\gamma })\mathrm{\mid }}$, where the sum runs over all closed geodesics.