Half-Integer Spectral Zeros for Leakage Suppression in Fast Transmon Pulses
The study found that symmetric flat-top pulses with cosine ramps have exact spectral zeros at half-integer values of ramp duration times anharmonicity ($ au|\alpha|=n+1/2$). This condition causes destructive interference between the rising and falling pulse edges, predicting minima in leakage. Numerical simulations confirm this sequence for various pulse durations, showing that population weighting explains the small deviations from these ideal half-integer points.