Planar qubits having increased coherence times
View Patent ↗An interdigitated capacitor includes a substrate and a pair of comb-like electrodes both formed on the semiconductor substrate and horizontally arranged thereon, each of the pair of comb-like electrodes including finger electrodes having a curved profile.
1. A capacitor, comprising:
a semiconductor substrate;
a left set of comb-like electrodes, the left set of comb-like electrodes both formed on the semiconductor substrate and horizontally arranged thereon, the left set of comb-like electrodes including finger electrodes having a curved profile;
a right set of comb-like electrodes, the right set of comb-like electrodes both formed on the semiconductor substrate and horizontally arranged thereon, the right set of comb-like electrodes including finger electrodes having a curved profile; and
a superconducting junction physically positioned in between a right most finger electrode of all the finger electrodes in the left set of comb-like electrodes and a left most finger electrode of all the finger electrodes in the right set of comb-like electrodes, such that a left side of the superconducting junction is closer to the right most finger electrode in the left set of comb-like electrodes as compared to a left most finger electrode in the left set of comb-like electrodes and such that a right side of the superconducting junction is closer to the left most finger electrode in the right set of comb-like electrodes as compared to a right most finger electrode in the right set.
2. The capacitor as claimed in claim 1 , further comprising bus lines coupling the left set of comb-like electrodes.
3. The capacitor as claimed in claim 1 , further comprising signal lines coupled to the left set of comb-like electrodes.
4. The capacitor as claimed in claim 1 , wherein the finger electrodes of one of the left set of comb-like electrodes are interweaved with the finger electrodes of another of the left set of comb-like electrodes.
5. The capacitor as claimed in claim 4 wherein the finger electrodes of one of the left set of comb-like electrodes and the finger electrodes of another of the left set of comb-like electrodes are separated by a gap.
6. The capacitor as claimed in claim 5 wherein the gap is constant.
7. The capacitor as claimed in claim 5 wherein the gap is variable depending on a local charge concentration along the finger electrodes.
8. The capacitor as claimed in claim 1 wherein the curved profile is a sinusoidal curve.
9. The capacitor as claimed in claim 8 wherein the sinusoidal curve has a period and amplitude that determines a capacitance of the capacitor.
10. A qubit, comprising:
a capacitor, including:
a semiconductor substrate;
a left set of comb-like electrodes, the left set of comb-like electrodes both formed on the semiconductor substrate and horizontally arranged thereon, the left set of comb-like electrodes including finger electrodes having a curved profile;
a right set of comb-like electrodes, the right set of comb-like electrodes both formed on the semiconductor substrate and horizontally arranged thereon, the right set of comb-like electrodes including finger electrodes having a curved profile; and
a superconducting junction disposed on the semiconductor substrate and coupled to the capacitor;
wherein the superconducting junction is physically positioned in between a right most finger electrode of all the finger electrodes in the left set of comb-like electrodes and a left most finger electrode of all the finger electrodes in the right set of comb-like electrodes, such that a left side of the superconducting junction is closer to the right most finger electrode in the left set of comb-like electrodes as compared to a left most finger electrode in the left set of comb-like electrodes and such that a right side of the superconducting junction is closer to the left most finger electrode in the right set of comb-like electrodes as compared to a right most finger electrode in the right set.
11. The qubit as claimed in claim 10 , further comprising bus lines coupling the left set of comb-like electrodes.
12. The qubit as claimed in claim 10 , further comprising signal lines coupled to the left set of comb-like electrodes.
13. The qubit as claimed in claim 10 , wherein the finger electrodes of one of the left set of comb-like electrodes are interweaved with the finger electrodes of another of the left set of comb-like electrodes.
14. The qubit as claimed in claim 13 wherein the finger electrodes of one of the left set of comb-like electrodes and the finger electrodes of another of the left set of comb-like electrodes are separated by a gap.
15. The qubit as claimed in claim 14 wherein the gap is constant.
16. The qubit as claimed in claim 14 wherein the gap is variable depending on a local charge concentration along the finger electrodes.
17. The qubit as claimed in claim 10 wherein the curved profile is a sinusoidal curve.
18. The qubit as claimed in claim 17 wherein the sinusoidal curve has a period and amplitude that determines a capacitance of the capacitor.