\(\newcommand{\D}{\text{d}} \newcommand{\I}{\text{i}} \newcommand{\E}{\text{e}} \newcommand{\Prob}{\mathbb{P}} \newcommand{\Expect}{\mathbb{E}} \newcommand{\Var}{\text{Var}} \newcommand{\PAvg}[1]{\left[#1\right]} \newcommand{\Avg}[1]{\left\langle#1\right\rangle} \newcommand{\AvgJ}[1]{\Avg{#1}_{\bm J}} \newcommand{\AvgDyn}[1]{\Avg{#1}_{\text{dyn.}}} \newcommand{\CAvg}[2]{\Avg{#1}_{\left|#2\right.}} \newcommand{\Devi}{\mathfrak{d}}\)

ポアソン分布 (Poisson distribution)