Improved qubit designs for quantum circuits

A method of fabricating a quantum circuit assembly, the method comprising:

• depositing a layer comprising one or more superconductive materials over a substrate;
• patterning the layer to form a first element and a second element of a first qubit device, and to form a coupling component configured to capacitively couple to a portion of the first element so that a capacitance between the coupling component and the portion of the first element is greater than a capacitance between the first element and the second element;
• and
• forming one or more non-linear inductive elements of the first qubit device so that each of the first and the second elements are connected to the one or more non-linear inductive elements.

A quantum circuit assembly comprising:

• a substrate;
• a coupling component provided over, on, or at least partially in the substrate and comprising:
• a first end portion forming a first electrode of a first capacitor for coupling the coupling component to a first qubit device, where a portion of the first qubit device opposite the first end portion forms a second electrode of the first capacitor, and
• a second end portion forming a first electrode of a second capacitor for coupling the coupling component to a second qubit device, where a portion of the second qubit device opposite the second end portion forms a second electrode of the second capacitor,
• wherein:
• one or more corners of the first end portion or of the second end portion are rounded.