P μ = ( E c , p → ) = ℏ K μ = ℏ ( ω c , k → ) {\displaystyle P^{\mu }=\left({\frac {E}{c}},{\vec {p}}\right)=\hbar K^{\mu }=\hbar \left({\frac {\omega }{c}},{\vec {k}}\right)} Classical statistical mechanics requires the existence of h (but does not define its value).
P μ = ( E c , p → ) = ℏ K μ = ℏ ( ω c , k → ) {\displaystyle P^{\mu }=\left({\frac {E}{c}},{\vec {p}}\right)=\hbar K^{\mu }=\hbar \left({\frac {\omega }{c}},{\vec {k}}\right)} Mekanika statistik klasik membutuhkan adanya h (tapi tidak mendefinisikan nilainya).