RK4 Integration for Stochastic Inflation
def rk4_stochastic(phi, t, dt, H, V_prime):
k1 = (-V_prime(phi)/(3*H) + noise(H, dt)) * dt
k2 = (-V_prime(phi + 0.5*k1)/(3*H) + noise(H, dt)) * dt
k3 = (-V_prime(phi + 0.5*k2)/(3*H) + noise(H, dt)) * dt
k4 = (-V_prime(phi + k3)/(3*H) + noise(H, dt)) * dt
return phi + (k1 + 2*k2 + 2*k3 + k4)/6
Sensitivity Analysis:
r/r0.2% r/r0.2% per 1% 1% change in qiqi /5% /5% for H/H=10% H/H=10%.
A4. Experimental Signatures
Extra-Dimensional Fingerprints
