diff --git a/physics.tex b/physics.tex
index 11d736d..0583b04 100644
--- a/physics.tex
+++ b/physics.tex
@@ -5,7 +5,12 @@
 
 \newcommand{\hilbert}{\mathcal{H}}
 \newcommand{\one}{\mathbbm{1}}
+\newcommand{\zero}{\pmb{0}}
+\newcommand{\aDs}{{\hat{a}}}
+\newcommand{\aCr}{{\aDs^\dagger}}
+\newcommand{\nOp}{{\hat{n}}}
 
 \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