Theory
V(x) = V₀[(x/a)²-1]² + ε·x/a
ΔE ∝ exp(-S_inst/ℏ)
S_inst = ∫√(2mV(x))dx
Tunneling splits degenerate levels by ΔE ∝ exp(-barrier/ℏ). The symmetric double well has even/odd parity eigenstates. The time-evolution shows coherent oscillation between wells at frequency ΔE/ℏ (Rabi-like tunneling).