Long-range coupling qubits in quantum computing with energy loss protection via multi-mode and fluxonium qubits

A method of performing operations across a long-range qubit coupling device with energy loss protection, the method comprising:

• providing a device including a first transmon coupler in selective electrical connection between a first fluxonium qubit and a first tunable coupler qubit;
• a second transmon coupler in selective electrical connection between a second fluxonium qubit and a second tunable coupler qubit;
• and a long-range coupler in selective electrical connection with the first fluxonium qubit and the second fluxonium qubit;
• operating the device in a first state to transmit information between the first tunable coupler qubit and the first fluxonium qubit, and to transmit information between the second tunable coupler qubit and the second fluxonium qubit;
• and
• operating the device in a second state to transmit information between the long-range coupler, the first fluxonium qubit, and the second fluxonium qubit.

A device comprising:

• a first fluxonium qubit coupled to a first tunable coupler qubit by a first transmon coupler;
• a second fluxonium qubit coupled to a second tunable coupler qubit by a second transmon coupler;
• and
• a long-range coupler coupled to the first fluxonium qubit and the second fluxonium qubit;
• wherein the first tunable coupler qubit includes a first B mode and the second tunable coupler qubit includes a second B mode, and the first B mode of the first tunable coupler qubit and the second B mode of the second tunable coupler qubit are coupled to the first transmon coupler and the second transmon coupler.