density being independent of the target density,
i.e., <span class="math inline">\(p(\rho | \theta) = p(\rho)\)</span>, the first term in the
momentum time derivative, <span class="math inline">\({\partial T} / {\partial \theta}\)</span> is
zero, yielding the pair time derivatives</p>
<p><span class="math display">\[
\begin{array}{rcl}
\frac{d \theta}{d t} &amp; = &amp; +\frac{\partial T}{\partial \rho}
\\[2pt]
\frac{d \rho}{d t} &amp; = &amp; -\frac{\partial V}{\partial \theta}.
\end{array}
\]</span></p>
<