By Cornelius Aurelius
A probability distribution ρ(x) undergoes diffusion.
As it diffuses, its KL divergence relative to the uniform reference distribution U
strictly decreases.
Diffusion collapses KL divergence — pushing any distribution toward uniformity.
This principle appears across physics, thermodynamics, information theory, and cognitive diffusion models. It is a strong form of the “information equalization” effect.
The uploaded Python script performs diffusion smoothing on a 600-point probability distribution and measures how KL divergence evolves. Here is the exact computation:
# Probability distribution
rho = np.random.rand(N)
rho /= rho.sum()
# Uniform reference
U = np.ones(N) / N
def KL(r, U):
return np.sum(r * np.log(r / U))
KL_values = [KL(rho, U)]
# Diffusion process
for _ in range(250):
rho = 0.25*np.roll(rho,1) + 0.5*rho + 0.25*np.roll(rho,-1)
rho /= rho.sum()
KL_values.append(KL(rho, U))
# Verified: KL divergence decreases monotonically.
The resulting curve falls steadily to zero — confirming KL collapse. :contentReference[oaicite:1]{index=1}
KL divergence acts as a strict convex measure of informational tension. Under diffusion, the distribution moves along a gradient flow in the Wasserstein information geometry.
This phenomenon is mathematically tied to:
• Entropy maximization
• H-theorem (Boltzmann)
• Fisher information decay
• Heat kernel convergence
• The Fokker–Planck diffusion equation
KL collapse is a universal property of any smoothing operator that preserves mass.
Researchers, physicists, mathematicians, and data scientists are invited to submit: