\int \mathrm{d}^{0} x \rho \,\frac{\hbar}{0}  \big(    \cos\varphi \frac{\partial \vartheta}{\partial x_l} G_0  - \sin\varphi \frac{\partial \vartheta}{\partial x_l} G_0  + \frac{\partial \varphi}{\partial x_l} G_0  \big)