Regensburg 2025 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 36: Materials and Devices for Quantum Technology II
HL 36.5: Talk
Wednesday, March 19, 2025, 16:00–16:15, H13
The Kitaev transmon qubit: design, readout and operation — •Tobias Kuhn and Monica Benito — Augsburg University, Augsburg, Germany
Fermionic-parity qubits are very stable but cannot be operated in isolation. Coupling two parity qubits allows us to construct parity-spin qubit states within one global parity [1]. Its degeneracy and non-locality should improve T2 and T1 times [2]. A parity qubit can be realized in a double quantum dot connected via a common superconducting lead, where elastic cotunneling t as well as crossed Andreev reflection Δ preserve parity. This minimal Kitaev chain possesses degenerate distinct-parity states at the sweetspot Δ=t[1]. Weakly coupling two minimal Kitaev chains inside a transmon loop introduces an additional Josephson potential which is a consequence of the emerging parity-spin qubit [3]. This hybrid device combines the advantages of both quantum dots and transmons to promise a high-fidelity qubit device we call Kitmon (Kitaev transmon). We theoretically analyze even and odd global parity subspaces of the Kitaev junction and show that flux spectroscopy in a circuit QED implementation [4] determines global parity. Additionally, we derive an effective Hamiltonian depending on the transmon excitation state, which is useful for single qubit operations and qubit readout. [1] M. Leijnse and K. Flensberg, Phys. Rev. B 86, 134528 (2012) [2] G.-L. Guo, H.-B. Leng, and X. Liu, New J. Phys. 26, 063005 (2024) [3] D. M. Pino, R. S. Souto, and R. Aguado, Phys. Rev. B 109, 075101 (2024) [4] L. Peri, M. Benito, C. J. B. Ford, and M. F. Gonzalez-Zalba, npj Quantum Inf 10, 1 (2024)
Keywords: parity qubit; Kitaev chain; transmon qubit; circuit QED; high fidelity qubit device