Ground discontinuities for thermal isolation

A superconducting quantum mechanical computer comprising:

• a refrigeration system comprising a temperature-controlled vessel;
• a quantum processor disposed within the temperature-controlled vessel, the quantum processor comprising a plurality of qubits;
• and
• a superconducting circuit disposed inside the temperature-controlled vessel, the superconducting circuit comprising:
• a substrate;
• a first electrical conductor and a second electrical conductor provided on the substrate and spaced apart to provide a gap therebetween, wherein the first electrical conductor and the second electrical conductor are electrically decoupled by providing the gap between the first electrical conductor and the second electrical conductor within the substrate;
• and
• a third electrical conductor coupled to the first electrical conductor and the second electrical conductor, wherein the third electrical conductor comprises Copper-Nickel (CuNi) having an electrical resistivity that is approximately 3.8×10−8 Ωm at ambient temperature and a thermal conductivity that is between about 25 W/m° K and 40 W/m° K.

A method of manufacturing a quantum mechanical circuit comprising:

• providing a substrate having a top face and a bottom face;
• forming a conductive layer on at least one of the top face or the bottom face of the substrate;
• and
• forming conductor lines in a selected pattern on the substrate by removing portions of the conductive layer, the conductor lines including a first electrical conductor and a second electrical conductor on the substrate, the first electrical conductor and the second electrical conductor being spaced apart and separated by a gap therebetween, wherein the first electrical conductor and the second electrical conductor are electrically decoupled by providing the gap between the first electrical conductor and the second electrical conductor within the substrate and by providing blind vias through the substrate that are not aligned with one another to reduce electrical coupling between the first electrical conductor and the second electrical conductor.