How can I include a "\DeltaT" as a subscript in Matplotlib?

I would like to write q, with the subscript \DeltaT. When I write r'q${\DeltaT}$', I get the error: Unknown symbol: \DeltaT, found ''. When I simply write r'q$\Delta$' or r'q$_T$', it works fine, but I can't manage to have the "\Delta" and the "T" together. Does anyone know how to fix this?

thanks!

Solution

You need to put a space between \Delta and T:

from matplotlib import pyplot
fig, ax = pyplot.subplots()
ax.text(0.5, 0.5, r"$x_{\Delta T}$", fontsize=40)