2026/06/06 by Omer Guleryuz
#hep-th #gr-qc
Swampland and compactification data tell us where a chosen EFT description can lose parametric control; stochastic cosmology asks which histories survive near that edge. We turn this question into a survival problem for fluctuating moduli over cosmological time scales. Given a valid stochastic generator, hard loss surfaces, soft degradation profiles, and finite horizons define a survival probability, whose logarithm is the survival action. The Doob transform then converts this logarithmic survival cost into the drift of the ensemble conditioned to remain on the controlled side. Near a regular hard boundary with nonzero normal diffusion, the inward normal component of the conditioned response is universal: it is fixed at leading order by the proper distance to the wall and the normal diffusion coefficient. The same finite-horizon construction also determines loss probabilities, first-exit statistics, survival hazards, and the control margin required to retain a prescribed fraction of histories. In this way, tower/species cutoffs, weak-coupling limits, string and Kaluza-Klein thresholds, and carefully qualified potential-based diagnostics acquire stochastic boundary layers without becoming microscopic forces. The inverse map tests when a conditioned drift is compatible with a scalar operational loss surface and reconstructs its boundary-normal Doob class. The construction therefore gives a stochastic survival interface between quantum-gravity control data and the cosmological histories that remain inside the prescribed EFT domain.