  We introduce interaction entropies, which can be represented as logarithmic
couplings of certain cycles on a class of algebraic curves of arithmetic
interest. In particular, via interaction entropies for Legendre-Ramanujan
curves $ Y^n=(1-X)^{n-1}X(1-\alpha X)$ ($ n\in\{6,4,3,2\}$), we reformulate the
Kontsevich-Zagier integral representations of weight-4 automorphic Green's
functions $ G_2^{\mathfrak H/\overline{\varGamma}_0(N)}(z_1,z_2)$
($N=4\sin^2(\pi/n )\in\{1,2,3,4\}$), in a geometric context. These geometric
entropies allow us to establish algebraic relations between certain weight-4
automorphic self-energies and special values of weight-6 automorphic Green's
functions.
