A device includes: a first qubit including a first co-planar waveguide; a second qubit including a second co-planar waveguide, in which the second co-planar waveguide crosses the first co-planar waveguide; and a qubit coupler including a loop having a first lobe and a second lobe, in which a first portion of the first lobe extends parallel to the first co-planar waveguide, a second portion of the first lobe extends parallel to the second co-planar waveguide, a first portion of the second lobe extends parallel to the first co-planar waveguide, and a second portion of the second lobe extends parallel to the second co-planar waveguide.