Hybrid Circuit QED with Spin Qubits

Hybrid devices integrating quantum dots with Josephson junctions are gaining interest because they combine spin-based quantum computing with circuit quantum electrodynamics (circuit QED) methods. In particular, Andreev spin qubits have shown significant experimental progress including strong two-qubit coupling, and are predicted to exhibit all-to-all connectivity. Here we propose superconducting singlet-triplet (SST) qubits that rely on parallel-aligned double quantum dots in Josephson junctions. While Andreev spin qubits require spin-orbit interaction to unlock the spin degree-of-freedom, SST qubits do not require spin-orbit interaction, making the advantages of hybrid devices available to a wider range of materials. Similar to Andreev spin qubits, the qubit states couple to the superconducting phase across the junction, which allows for control and readout using circuit QED, and supports all-to-all connectivity. Only $N$ flux lines are required to perform any single- and two-qubit gate among $N$ qubits, and thus the overhead of control lines is small. Finally, linear protection from charge or flux noise makes these qubits interesting candidates for a future quantum processor.Hybrid devices integrating quantum dots with Josephson junctions are gaining interest because they combine spin-based quantum computing with circuit quantum electrodynamics (circuit QED) methods. In particular, Andreev spin qubits have shown significant experimental progress including strong two-qubit coupling, and are predicted to exhibit all-to-all connectivity. Here we propose superconducting singlet-triplet (SST) qubits that rely on parallel-aligned double quantum dots in Josephson junctions. While Andreev spin qubits require spin-orbit interaction to unlock the spin degree-of-freedom, SST qubits do not require spin-orbit interaction, making the advantages of hybrid devices available to a wider range of materials. Similar to Andreev spin qubits, the qubit states couple to the superconducting phase across the junction, which allows for control and readout using circuit QED, and supports all-to-all connectivity. Only $N$ flux lines are required to perform any single- and two-qubit gate among $N$ qubits, and thus the overhead of control lines is small. Finally, linear protection from charge or flux noise makes these qubits interesting candidates for a future quantum processor.

quant-pharXiv:2607.09508Jul 13, 20260 citations

Hybrid Circuit QED with Electrons on Helium

Ge Yang

Bulletin of the American Physical SocietyMar 16, 20170 citations

Circuit QED with phase-biased qubits

Jérôme Bourassa, Alexandre Blais, Michel Devoret +1 more

Bulletin of the American Physical SocietyMar 12, 20080 citations

Quantum state transfer between hybrid qubits in a circuit QED

Zhi‐Bo Feng

In this Brief Report, we propose a theoretical scheme to transfer quantum states between superconducting charge qubits and semiconductor spin qubits in a circuit QED device. Under dispersive conditions, resonator-assisted state transfer between qubits can be performed controllably only by addressing the flux bias applied to the charge qubits. The low infidelity and existing advantages show that the proposal may provide an effective route toward scalable quantum-information transfer with solid-state hybrid qubits.In this Brief Report, we propose a theoretical scheme to transfer quantum states between superconducting charge qubits and semiconductor spin qubits in a circuit QED device. Under dispersive conditions, resonator-assisted state transfer between qubits can be performed controllably only by addressing the flux bias applied to the charge qubits. The low infidelity and existing advantages show that the proposal may provide an effective route toward scalable quantum-information transfer with solid-state hybrid qubits.

Physical Review AJan 25, 201231 citations

Circuit quantum electrodynamics with a spin qubit

Karl D. Petersson, Louis W. McFaul, Michael D. Schroer +4 more

arXiv:1205.6767NatureOct 1, 2012463 citations

N

flux lines are required to perform any single- and two-qubit gate among

N

qubits, and thus the overhead of control lines is small. Finally, linear protection from charge or flux noise makes these qubits interesting candidates for a future quantum processor.