In phase retrieval we want to recover an unknown signal $\boldsymbol
x\in\mathbb C^d$ from $n$ quadratic measurements of the form $y_i =
|\langle{\boldsymbol a}_i,{\boldsymbol x}\rangle|^2+w_i$ where $\boldsymbol
a_i\in \mathbb C^d$ are known sensing vectors and $w_i$ is measurement no