Multi-qubit coupling structure
A quantum qubit coupling structure is provided. The quantum qubit coupling structure includes a plurality of qubits and a variable capacitor electrically connected between the plurality of qubits to vary coupling constants of the plurality of qubits.
1. A multi-qubit coupling structure comprising:
a plurality of qubits;
a variable capacitor electrically connected to the plurality of qubits;
a substrate; and
an electrode pattern formed on the substrate to apply a voltage to the variable capacitor,
wherein the variable capacitor is configured to vary coupling constants of the plurality of qubits,
wherein the variable capacitor comprises:
a first planar pattern formed on the substrate;
an intermediate layer formed on the first planar pattern and having a dielectric constant which varies based on an applied voltage; and
a second planar pattern formed on the intermediate layer,
wherein the multi-qubit coupling structure further comprises a material layer formed on the substrate to cover the electrode pattern and the first planar pattern, and
wherein a portion of the material layer, which corresponds to an intermediate portion between the first and the second planar patterns, forms the intermediate layer.
2. The multi-qubit coupling structure of claim 1 , wherein the plurality of qubits are superconducting qubits formed by using superconducting materials.
3. The multi-qubit coupling structure of claim 2 , wherein the plurality of qubits have a stack structure comprising:
a first superconducting material layer;
a second superconducting material layer; and
a dielectric layer between the first and the second superconducting material layers.
4. The multi-qubit coupling structure of claim 1 , wherein the variable capacitor comprises superconducting materials.
5. The multi-qubit coupling structure of claim 1 , wherein the intermediate layer is formed of at least one of ferroelectric materials and piezoelectric materials.
6. The multi-qubit coupling structure of claim 5 , wherein the first and the second planar patterns are formed of superconducting materials.
7. The multi-qubit coupling structure of claim 6 , wherein the first planar pattern, the second planar pattern, and the plurality of qubits are formed of the same superconducting materials.
8. The multi-qubit coupling structure of claim 1 , wherein the first and the second planar patterns are formed of superconducting materials.
9. The multi-qubit coupling structure of claim 8 , wherein the first planar pattern, the second planar pattern, and the plurality of qubits are formed of the same superconducting materials.
10. The multi-qubit coupling structure of claim 1 , wherein the variable capacitor is electrically connected to the plurality of qubits via superconducting materials.
11. The multi-qubit coupling structure of claim 1 , further comprising an insulating layer formed on the material layer,
wherein the plurality of qubits are formed on the insulating layer.
12. The multi-qubit coupling structure of claim 11 , wherein the insulating layer covers the second planar pattern, and
the first planar pattern is electrically connected to a first qubit from among the plurality of qubits through a first via-hole formed in the material layer and the insulating layer.
13. The multi-qubit coupling structure of claim 12 , wherein the second planar pattern is electrically connected to a second qubit from among the plurality of qubits via a second via-hole formed in the insulating layer.
14. The multi-qubit coupling structure of claim 1 , wherein the material layer is formed of at least one of ferroelectric materials and piezoelectric materials, and the first and the second planar patterns are formed of superconducting materials.
15. A multi-qubit coupling structure comprising:
a plurality of qubits;
a variable capacitor electrically connected to the plurality of qubits,
a substrate; and
an electrode pattern formed on the substrate to apply a voltage to the variable capacitor,
wherein the variable capacitor is a tunable superconducting capacitor configured to vary coupling constants of the plurality of qubits based on adjustment of a voltage applied to the variable capacitor,
wherein the variable capacitor comprises:
a first planar pattern formed on the substrate;
an intermediate layer formed on the first planar pattern and having a dielectric constant which varies based on an applied voltage; and
a second planar pattern formed on the intermediate layer,
wherein the multi-qubit coupling structure further comprises a material layer formed on the substrate to cover the electrode pattern and the first planar pattern, and
wherein a portion of the material layer, which corresponds to an intermediate portion between the first and the second planar patterns, forms the intermediate layer.