\label{fig:cs-spectrum}
Spectrum of one-dimensional complex-scaled single-particle Hamiltonian with potential $v(x) = 3(x^2 - 2) \mathrm{e}^{-x^2 / 4}$ and $\theta=0.5$. The lowest-energy resonance, here located close to the origin, does not lie exactly on the real axis but has an imaginary part of about~$-10^{-5}$.