Table of Contents
Equation of motion
The equations of motion are derived here with the help of the Heisenberg EoM. Starting in the Heisenberg picture the time evolution of an operator is \begin{equation} \frac{\partial}{\partial t} \hat{O}_\text{H} (x,t) = \left[ \hat{O}_\text{H} (x,t) , \hat{H}_\text{H} (t) \right] + \left( \frac{\partial}{\partial t} \hat{O}_\text{S} (x) \right)_\text{H} \quad . \end{equation}
Fermionic Field Operator
The EoM for the electronic creation and annihilation operator is \begin{equation} \frac{\partial}{\partial t} \hat{\Psi}_\text{H} (x,t) = \dots \end{equation} according to the calculation here.
Condition: \begin{equation} \nu (\vec{r},\vec{r}^\prime) = \nu (\vec{r}^\prime,\vec{r}) \end{equation}
Particle Number Operator
The EoM of the particle number operator \begin{equation} \frac{\partial}{\partial t} \hat{n}_\text{H}= \dots \end{equation} is of the form of a continuity equation. The calculation is done here.
Current Density Operator
Wtih the help of the EoM of the fermionic field operator, the EoM for the current density operator $J(x,t)$ becomes \begin{equation} \frac{\partial}{\partial t} \hat{J}_\text{H} (x,t) = \frac{\partial}{\partial t} \hat{j}_\text{H} (x,t) + \frac{\partial}{\partial t} \hat{j}_\text{d,H} (x,t) = \dots + \dots \quad . \end{equation} Insert Link to para and diramagnetic definitions This holds for symmetric correlation potentials \begin{equation} \nu (\vec{r},\vec{r}^\prime) = \nu (\vec{r}^\prime,\vec{r}) \end{equation} and (Do a page where I discuss where this occurs) \begin{equation} \frac{\partial}{\partial t} \frac{\partial}{\partial k} = \frac{\partial}{\partial k} \frac{\partial}{\partial t} \quad . \end{equation} The calculation can be found here.