is re-written using the polar form for the wave function ψ ψ = R exp ⁡ ⁡ ( i S / ℏ ℏ ) with real-valued functions R and S , where R is the amplitude (absolute value) of the wave function ψ ψ , and S / ℏ ℏ its phase. This yields two equations: from the imaginary and real part of the Schrödinger equation follow the continuity equation and the quantum Hamilton–Jacobi equation respectively.