A superconducting cross-bar switch system comprising: a first input port (IN 1 , Port 1) coupled to a first output port (OUT 1 , Port 3) through a first Josephson junction (J 1 ) or first series array of Josephson junctions as a first variable inductance coupling element, and a second output port (OUT 2 , Port 4) through a third Josephson junction (J 3 ) or third series array of Josephson junctions as a third variable inductance coupling element; a second input port (IN 2 , Port 2) coupled to the first output port through a second Josephson junction (J 2 ) or second series array of Josephson junctions as a second variable inductance coupling element, and the second output port through a fourth Josephson junction (J 4 ) or fourth series array of Josephson junctions as a fourth variable inductance coupling element; a first resonator coupled between the first input port and the first and third variable inductance coupling elements, a second resonator coupled between the second input port and the second and fourth variable inductance coupling elements, a third resonator coupled between the first output port and the first and second variable inductance coupling elements, and a fourth resonator coupled between the second output port and the third and fourth variable inductance coupling elements; and a switch controller configured to set the first and fourth variable inductance coupling elements to a low inductance, and the second and third variable inductance coupling elements to a high inductance to allow selective routing of signals between the first input port to the first output port and the second input port to the second output port in a bar state, and set the first and fourth variable inductance coupling elements to a high inductance, and the second and third variable inductance coupling elements to a low inductance to allow selective routing of signals between the first input port to the second output port and the second input port to the first output port in a cross state. a first input port (IN 1 , Port 1) coupled to a first output port (OUT 1 , Port 3) through a first Josephson junction (J 1 ) or first series array of Josephson junctions as a first variable inductance coupling element, and a second output port (OUT 2 , Port 4) through a third Josephson junction (J 3 ) or third series array of Josephson junctions as a third variable inductance coupling element; a second input port (IN 2 , Port 2) coupled to the first output port through a second Josephson junction (J 2 ) or second series array of Josephson junctions as a second variable inductance coupling element, and the second output port through a fourth Josephson junction (J 4 ) or fourth series array of Josephson junctions as a fourth variable inductance coupling element; a first resonator coupled between the first input port and the first and third variable inductance coupling elements, a second resonator coupled between the second input port and the second and fourth variable inductance coupling elements, a third resonator coupled between the first output port and the first and second variable inductance coupling elements, and a fourth resonator coupled between the second output port and the third and fourth variable inductance coupling elements; and a switch controller configured to set the first and fourth variable inductance coupling elements to a low inductance, and the second and third variable inductance coupling elements to a high inductance to allow selective routing of signals between the first input port to the first output port and the second input port to the second output port in a bar state, and set the first and fourth variable inductance coupling elements to a high inductance, and the second and third variable inductance coupling elements to a low inductance to allow selective routing of signals between the first input port to the second output port and the second input port to the first output port in a cross state. <EOS>