High-fidelity Rydberg controlled-Z gates with optimized pulses

Abstract

High-fidelity controlled-Z (CZ ) gates are essential and mandatory to build a large-scale quantum computer. In neutral atoms, the strong dipole–dipole interactions between their Rydberg states make them one of the pioneering platforms to implement CZ gates. Here we numerically investigate the optimized pulses to generate a high-fidelity Rydberg C Z gate in a three-level ladder-type atomic system. By tuning the temporal shapes of Gaussian or segmented pulses, the populations on the intermediate excited states are shown to be suppressed within the symmetric gate operation protocol, which leads to a C Z gate with a high Bell fidelity up to 99.92 % . These optimized pulses are robust to thermal fluctuations and the excitation field variations. Our results promise a high-fidelity and fast gate operation under amenable and controllable experimental parameters, which goes beyond the adiabatic operation regime under a finite blockade strength.

High-fidelity parallel entangling gates on a neutral-atom quantum computer

“…8 and a second one in which the amplitude is also varied. We note that, in the past, many schemes were proposed to implement two-qubit gates with Rydberg interactions 5,8,29,35,[67][68][69][70][71][72][73][74][75] , to engineer robustness to errors 28,[76][77][78][79][80][81][82][83][84] and to perform multi-qubit gates [85][86][87][88][89][90][91] . The fixed-amplitude gate, which we refer to as 'time-optimal' because it resembles and is only 0.2% slower than the Jandura-Pupillo gate 8 , has the phase profile given by…”