diff --git a/physics.tex b/physics.tex
index fd7597d..c849d77 100644
--- a/physics.tex
+++ b/physics.tex
@@ -13,4 +13,6 @@
 \newcommand{\probb}[2]{\text{prob}\left[ #1\vphantom{#2} \right. \left| \vphantom{#1}#2 \right]}
 \newcommand{\prob}[1]{\text{prob}\left[ #1 \right]}
 \newcommand{\diffPs}[1]{\partial_{#1}}
-\newcommand{\const}{{\text{const.}}}
\ No newline at end of file
+\newcommand{\const}{{\text{const.}}}
+
+\newcommand{\varianz}[2]{{\left(\Delta #1 \right)_{#2}}}