documentclass{article}
usepackage{mathtools}
usepackage{microtype}

begin{document}
$displaystyle
hat{H} = frac12 momega_text{m}^2 hat x_text{m}^2+frac{hat p_{text{m}}^2}{2m}
$

textls[500]{%
$displaystyle
hat{H} = frac12 momega_text{m}^2 hat x_text{m}^2+frac{hat p_{text{m}}^2}{2m}
$
}
end{document}