Salis, Gian

Date:   Thursday, July 23, 2020
Time:   10:00
Place:   scheduled Zoom meeting
Host:    Klaus Ensslin

Parametric two-qubit gates in a superconducting quantum computing platform

Gian Salis
IBM Research Zurich

The possibility to utilize different types of two-qubit gates on a single quantum computing platform adds flexibility in the decomposition of quantum algorithms. A larger hardware-native gate set may decrease the number of required gates, provided that all gates are realized with high fidelity. We implement controlled-Z (CZ) and exchange-type (iSWAP) gates between two superconducting qubits using a parametrically driven tunable coupler that mediates the interaction [1-5]. Using randomized benchmarking protocols, we estimate an error per gate of about 1% for both the CZ and the iSWAP gate. We argue that spurious ZZ-type couplings are the dominant error source for the iSWAP gate, and that phase stability of all microwave drives is of utmost importance.

[1] M. Roth et al., Phys. Rev. A 96, 062323 (2017)
[2] M. Roth et al., Phys. Rev. A 99, 022323 (2019)
[3] M. Ganzhorn et al., Phys. Rev. Applied 11, 044092 (2019)
[4] G. Salis et al., arXiv:2001.05243 (2020)
[5] M. Ganzhorn et al., arXiv:2005.05696 (2020)