“…Two-qubit gates preserving the biased feature of errors were proposed 21 , and high error-correction performance by concatenating the XZZX surface code 12 with KPOs 22 was numerically presented. Other research subjects on KPOs include fast gate operations and controls 9 , 23 – 26 , spectroscopy 27 , 28 , tomography 9 , 10 , 29 , Boltzmann sampling 30 , effects of strong pump field 31 , quantum phase transitions 6 , 7 , quantum chaos 1 , 32 , and trajectories 33 – 35 .…”