Investigation of an on-chip SNAIL coupler for Entangling Two-Transmons

Superconducting transmon qubits are a promising platform for quantum computation. One obstacle is that strong coupling between two qubits required to perform an entanglement gate often introduces single-qubit ZZ cross-talk that limits overall fidelity. To balance these two issues, we have designed a planar device with a Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL) as a coupler between two fixed frequency transmon qubits. By applying a parametric interaction to the coupler, unwanted cross-talk between the two qubits can be canceled and the two qubits can be entangled. The performance and fidelity of our proposed system are investigated at a nominal temperature of 10 mK using aluminum qubits on a silicon substrate.