Spectrum
ζ_A(s) = Σ λ_n^(-s)
ζ_A(s): —
ζ_A(-½) (vac.E): —
Weyl counting: —
Spectral gap: —
The spectral zeta function ζ_A(s) = Σ λ_n^(-s) encodes eigenvalue spectra. Analytic continuation to s=-1/2 yields zero-point energy — the mathematical heart of the Casimir effect, connecting quantum vacuum fluctuations to spectral geometry.