How to write labels in math mode

I am generating a surface plot and adding three axis labels. But, I want to write them in math mode, such as \rho_i or \widetilde{W}. How should I do it?

layout = go.Layout(
    title='M/G/1 plot',
    scene=dict(
        xaxis=dict(
            title = 'ΞΆ'
        ),
        yaxis=dict(
            title = 'ρ',
        ),
        zaxis=dict(
            title = 'W',
        )
    ),
    showlegend=False,
)

Dollar signs do not work in Jupyter Notebook.