Category: Epidemiology

Summary: Estimating when coupling to dormant refuge states turns an immune-imprinting-trapped escape peak into a broader active-dormant bridge across an antigenic valley.

Pathogen evolution can be trapped near a narrow escape lineage when cross-immunity and immune imprinting make movement across antigenic space difficult. This experiment asks when adding an explicit dormant or seed-bank state changes that picture, allowing the dominant growth mode to bridge an immune valley instead of staying concentrated near one active escape peak.

The script builds a dense symmetric operator that couples active antigenic states to dormant refuge states, then carries a threshold bracket across larger system sizes with iterative deepening. At each size it bisects the dormant-state coupling strength and tracks how much of the leading mode sits in the dormant valley and adjacent active shoulder regions, together with its participation ratio and leading eigenvalue.

That makes the project a structural transition study rather than a simple outbreak-growth calculation. The goal is to locate the threshold where dormancy stops acting as passive storage and instead becomes an active bridge across an otherwise blocked immune landscape.

Method: Dense symmetric eigensolves with iterative deepening and bisection on dormant-state coupling sigma across N=64 to 2048.

What is measured: Critical coupling threshold, bridge score, participation ratio, escape mass, shoulder mass, dormant mass, dormant-valley mass, leading eigenvalue, and bracket width.