Suppression of Qubit Crosstalk in a Tunable Coupling Superconducting Circuit

Publication Year
2018

Type

Journal Article
Abstract
We report the suppression of static ZZ crosstalk in a two-qubit, two-coupler superconducting circuit, where the ZZ interaction between the two qubits can be tuned to near zero. Characterization of qubit crosstalk is performed using randomized benchmarking and a two-qubit iSWAP gate is implemented using parametric modulation. We observe the dependence of single-qubit gate fidelity on ZZ interaction strength and identify effective thermalization of the tunable coupler as a crucial prerequisite for high fidelity two-qubit gates.
Journal
Physics Review Applied
Volume
12
Pages
054023

Parasitic crosstalk in superconducting quantum devices is a leading limitation for quantum gates. We demonstrate the suppression of static ZZ crosstalk in a two-qubit, two-coupler superconducting circuit, where the frequency of a tunable coupler can be adjusted such that the ZZ interaction from each coupler destructively interfere. We verify the crosstalk elimination with simultaneous randomized benchmarking, and use a parametrically activated iSWAP interaction to achieve a Bell state preparation fidelity of 98.5% and a âˆšiSWAP gate fidelity of 94.8% obtained via quantum process tomography.