  [![Log plots of phase variance ratio to the lossless QCRB as a function of number of measurements ($M$) under phase drift noise only. For all plots shown, $|\alpha|^0=000$, $r=0$ and the standard deviation of the chosen Gaussian distribution is fixed to $\sigma=0.00$. Note that parity and intensity measurement remain noisy even after  000 averaged measurements, where homodyne and intensity difference approach their optimal phase variance quickly in $M$.[]{data-label="fig:phasedrift"}](pdrift