Finite-Volume Effects in (g-2)_{μ}^{HVP,LO}.

An analytic expression is derived for the leading-order finite-volume effects arising in lattice QCD calculations of the hadronic-vacuum-polarization contribution to the muon's magnetic moment a_{μ}^{HVP,LO}≡(g-2)_{μ}^{HVP,LO}/2. For calculations in a finite spatial volume with periodicity L, a_{μ}^{HVP,LO}(L) admits a transseries expansion with exponentially suppressed L scaling. Using a Hamiltonian approach, we show that the leading finite-volume correction scales as exp[-M_{π}L] with a prefactor given by the (infinite-volume) Compton amplitude of the pion, integrated with the muon-mass-dependent kernel.