Category: Epidemiology

Summary: Estimating when mutation coupling overcomes immune imprinting and broadens epidemic growth from a single escape lineage into a distributed antigenic cloud.

Immune imprinting can trap pathogen evolution near a narrow escape lineage even when mutation and cross-immunity are both active. This experiment asks when mutation coupling becomes strong enough for the leading growth mode to spread across antigenic space instead of remaining localized near one favored lineage.

The model builds dense symmetric operators on a noisy antigenic landscape with an explicit imprinting valley, then uses iterative deepening to bisect the mutation-coupling threshold while increasing system size. By tracking localization of the leading mode, it distinguishes a single-lineage escape regime from a broader antigenic-cloud regime.

That makes the project a spectral transition study of multistrain evolution rather than a simple incidence simulation. The value is in locating the delocalization point directly and mapping how immune structure reshapes exploration of antigenic space.

Method: Dense symmetric eigensolves with iterative deepening and bisection on mutation coupling mu across N=64 to 2048 antigenic operators.

What is measured: Critical mutation-coupling threshold, localization or delocalization of the leading mode, antigenic-cloud spread, leading eigenvalue, and bracket width.