Incorporating arrays of josephson junctions in a josephson junction ring modulator in a josephson parametric converter

1. A Josephson parametric converter, comprising:

a multi-Josephson junction ring modulator having arrays of N Josephson junctions arranged in a ring configuration with nodes inter-dispersed between the arrays, wherein N is an integer having a value greater than one;

a first and a second resonator formed from lumped-element capacitors that shunt the multi-Josephson junction ring modulator and respectively enable a first and a second mode of the Josephson parametric converter; and

a first and a second LC circuit for respectively coupling the first and the second resonator to external feedlines.

2. The Josephson parametric converter of claim 1 , wherein the external feedlines comprise a first external feedline and a second external feedline, and wherein the first LC circuit is connected in series with the first external feedline connecting to the first resonator, and the second LC circuit is connected in series with the second external feedline connecting to the second resonator.

3. The Josephson parametric converter of claim 1 , wherein the first LC circuit is configured to correlate to an angular resonance frequency of the first resonator, and the second LC circuit is configured to correlate to an angular frequency of the second resonator.

4. The Josephson parametric converter of claim 1 , wherein the first and the second LC circuits are used to form a bandpass filter with the Josephson parametric converter.

5. The Josephson parametric converter of claim 1 , wherein inductances of at least one of the first and the second LC circuits comprise one or more superconducting lines.

6. The Josephson parametric converter of claim 1 , wherein inductances of at least one of the first and the second LC circuits comprise one or more arrays of Josephson junctions.

7. The Josephson parametric converter of claim 1 , wherein the N Josephson junctions in each of the arrays are connected in series.

8. The Josephson parametric converter of claim 1 , wherein the first resonator comprises at least one capacitor shunted across a first node and a third node from among the nodes, and the second resonator comprises at least one other capacitor shunted across a second node and a fourth node from among the nodes.

9. The Josephson parametric converter of claim 8 , wherein multi-Josephson junction ring modulator has two opposing pairs of nodes, a first of the two opposing pairs of nodes formed from the first node and the third node, and a second of the two opposing pairs of nodes formed from the second node and the fourth node.

10. The Josephson parametric converter of claim 1 , wherein the Josephson parametric converter is configured to perform wave mixing of three microwave signals for quantum information processing.

11. A method, comprising:

forming a Josephson parametric converter, wherein said forming step includes:

forming a multi-Josephson junction ring modulator having arrays of N Josephson junctions arranged in a ring configuration with nodes inter-dispersed between the arrays, wherein N is an integer having a value greater than one;

forming a first and a second resonator from lumped-element capacitors that shunt the multi-Josephson junction ring modulator and respectively enable a first and a second mode of the Josephson parametric converter; and

forming a first and a second LC circuit for respectively coupling the first and the second resonator to external feedlines.

12. The method of claim 11 , wherein the external feedlines comprise a first external feedline and a second external feedline, and wherein the first LC circuit is connected in series with the first external feedline connecting to the first resonator, and the second LC circuit is connected in series with the second external feedline connecting to the second resonator.

13. The method of claim 11 , wherein the first LC circuit is configured to correlate to an angular resonance frequency of the first resonator, and the second LC circuit is configured to correlate to an angular frequency of the second resonator.

14. The method of claim 11 , wherein the first and the second LC circuits are used to form a bandpass filter with the Josephson parametric converter.

15. The method of claim 11 , wherein inductances of at least one of the first and the second LC circuits comprise one or more superconducting lines.

16. The method of claim 11 , wherein inductances of at least one of the first and the second LC circuits comprise one or more arrays of Josephson junctions.

17. The method of claim 11 , wherein the N Josephson junctions in each of the arrays are connected in series.

18. The method of claim 11 , wherein forming the first and the second resonator comprise:

shunting at least one capacitor across a first node and a third node from among the nodes; and

shunting at least one other capacitor across a second node and a fourth node from among the nodes.

19. The method of claim 18 , wherein multi-Josephson junction ring modulator is formed to have two opposing pairs of nodes, a first of the two opposing pairs of nodes formed from the first node and the third node, and a second of the two opposing pairs of nodes formed from the second node and the fourth node.

20. The method of claim 11 , wherein the Josephson parametric converter is configured to perform wave mixing of three input waves for quantum information processing.