Speaker
Description
We propose an inflationary mechanism for primordial magnetic-field generation based on the reduced open-system dynamics of photon modes in de~Sitter space. The observable photon sector inside a causal patch is treated as a Gaussian subsystem, while the de~Sitter horizon acts as an effective environment at the Gibbons--Hawking temperature. Since the reduced state relaxes only with a finite rate toward a horizon-selected quasi-static branch, the redshift of the physical photon frequency drives imperfect tracking. This tracking failure appears as squeezing of the reduced Gaussian state and generates a super-horizon electromagnetic relic.
We solve the reduced Gaussian evolution in exact exponential inflation and derive the super-horizon relic spectrum. For the infrared-turnover branch (\alpha_0>4), the magnetic component yields a broad, non-helical primordial seed spectrum on astrophysically relevant scales for suitable reheating temperature and turnover position. After reheating, the electric component is screened by the radiation plasma, whereas the magnetic component remains frozen on cosmological scales.
The non-adiabatic electromagnetic energy density is parametrically small, (\rho_{\rm EM}^{\rm nad}\sim H^4), so it does not backreact for (H\ll M_{\rm Pl}). The mechanism requires no explicit non-minimal coupling in the Maxwell action; conformal tracking is instead effectively broken by finite-rate reduced open-system dynamics.
