Actually L is the classical Lagrangian of the one-dimensional system considered,

**Actually L is the classical Lagrangian of the one-dimensional system considered, 𝐿 ( 𝑥 , 𝑥 ˙ ) = 𝑇 − 𝑉 = 1 2 𝑚 | 𝑥 ˙ | 2 − 𝑉 ( 𝑥 ) \displaystyle L(x and the abovementioned "zigzagging" corresponds to the appearance of the terms exp ⁡ ( 𝑖 ℏ 𝜀 ∑ 𝑗 = 1 𝑛 + 1 𝐿 ( 𝑥 ~ 𝑗 , 𝑥 𝑗 − 𝑥 𝑗 − 1 𝜀 , 𝑗 ) ) \displaystyle \exp \left(\frac i\hbar \varepsilon \sum _j=1^n+1L\left(\tilde x_j