Spectral Gap of Markov Chains

Mixing time t_mix ≈ (1/gap)·log(1/ε) — eigenvalue gap λ₂ controls how fast the chain mixes


Chain Type

Simulation

λ₁=1 > λ₂ ≥ … ≥ λₙ ≥ -1
gap = 1 - λ₂
t_mix(ε) ≈ log(n/ε) / gap
‖μᵗ - π‖_TV ≤ (1-gap)ᵗ · √n