2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/16221In a Coulomb fluid confined to a domain $V$, the dielectric susceptibility tensor $χ_V$ depends on the shape of $V$, even in the thermodynamic $V\to\infty$ limit. This paper deals with the classical two-dimensional one-component plasma formulated in an elliptic $V$-domain, equilibrium statistical mechanics is used. For the dimensionless coupling constant $Γ=$ even positive integer, the mapping of the plasma onto a discrete one-dimensional anticommuting-field theory provides a new sum rule. This sum rule confirms the limiting value of $χ_V$ predicted by macroscopic electrostatics and gives the finite-size correction term to $χ_V$.22 pagesStatistical Mechanicstext