The exact LCU sampling overhead of collective diagonal unitaries: resonances and a continued-fraction dichotomy

Zhihui Wang, Sujit Roy, Manil Maskey +1

The minimal sampling overhead of the quadratic collective phase $e^{-i\gamma K^2}$ over one layer of single-qubit rotations is decided by the continued fraction of $\gamma /\pi$. Here $K$ is a c…