> is there a QM-equivalent model using only real-valued functions? Yes, the Wigner-Weyl transformation produces a completely equivalent way to formulate quantu

> is there a QM-equivalent model using only real-valued functions? Yes, the Wigner-Weyl transformation produces a completely equivalent way to formulate quantum mechanics without reference to complex numbers. The wavefunction over real space is replaced with a (generically not positive) real-valued pseudo-probability distribution on phase space called the Wigner function. https://en.m.wikipedia.org/wiki/Wigner–Weyl_transform https://en.m.wikipedia.org/wiki/Wigner–Weyl_transform