Co-planar waveguide flux qubits
A qubit device includes an elongated thin film uninterrupted by Josephson junctions, a quantum device in electrical contact with a proximal end of the elongated thin film, and a ground plane that is co-planar with the elongated thin film and is in electrical contact with a distal end of the elongated thin film, in which the thin film, the quantum device, and the ground plane comprise a material that is superconducting at a designed operating temperature.
1. An apparatus comprising:
a plurality of qubits arranged in a fully connected qubit network, the plurality of qubits comprising a first group of qubits and a second group of qubits,
wherein each qubit of the plurality of qubits comprises multiple coupling structures,
wherein, for each qubit of the first group of qubits,
a first coupling structure of the qubit is arranged to couple to a corresponding first coupling structure of each other qubit in the first group of qubits, and
a second coupling structure of the qubit is arranged to couple to a corresponding second coupling structure of each qubit in the second group of qubits, wherein the second coupling structure of each qubit of the first group of qubits is a separate structure from the corresponding second coupling structure of each qubit in the second group of qubits.
2. The apparatus of claim 1 , wherein, for each qubit of the second group of qubits,
a first coupling structure of the qubit is arranged to couple to a corresponding first coupling structure of each other qubit in the second group of qubits.
3. The apparatus of claim 1 , wherein each coupling structure of the multiple coupling structures comprises a co-planar waveguide.
4. The apparatus of claim 1 , wherein the multiple coupling structures of each qubit comprise a double-branched co-planar waveguide.
5. The apparatus of claim 1 , wherein each qubit of the plurality of qubits is a co-planar waveguide flux qubit.
6. The apparatus of claim 1 , the first group of qubits are arranged in a first array, and the second group of qubits are arranged in a second array, wherein the first array is aligned along a first direction, and the second array is aligned along a second direction that is different than the first direction.
7. The apparatus of claim 6 , wherein the first direction is orthogonal to the second direction.
8. The apparatus of claim 1 , wherein, for each qubit of the first group of qubits,
the first coupling structure of the qubit is arranged to couple to the corresponding first coupling structure of each other qubit in the first group of qubits at a respective coupling location,
wherein each coupling location comprises a corresponding coupling element separate from both first coupling structures at the coupling location.
9. The apparatus of claim 8 , wherein, at each coupling location, a cross-over bridge allows one of the first coupling structures at the coupling location to pass over the other first coupling structure at the coupling location.
10. The apparatus of claim 8 , wherein each coupling element comprises a thin-film coupler.
11. The apparatus of claim 8 , wherein each coupling element comprises a coupler loop.
12. The apparatus of claim 1 , wherein each qubit of the plurality of qubits comprises a corresponding readout device.
13. The apparatus of claim 1 , wherein each qubit of the plurality of qubits comprises a bias control device.