Quantum Gates Built on a Spin Qubit and a Kitaev Parity Qubit

@misc{liu2026quantum,
  title = {{Quantum Gates Built on a Spin Qubit and a Kitaev Parity Qubit}},
  author = {Zhi-Hai Liu and Jiang Zhang and Guilu Long and H. Q. Xu},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.28924},
  eprint = {2609.28924},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.28924},
}

TY  - UNPB
TI  - Quantum Gates Built on a Spin Qubit and a Kitaev Parity Qubit
AU  - Zhi-Hai Liu
AU  - Jiang Zhang
AU  - Guilu Long
AU  - H. Q. Xu
PY  - 2026
DA  - 2026/09/24
PB  - arXiv
DO  - 10.48550/arxiv.2609.28924
UR  - https://arxiv.org/abs/2609.28924
AB  - Spin is typically traced out in the description of quantum-dot-based Kitaev chains to simplify the construction of Majorana fermions. Yet the intrinsic spin structure of poor-man's Majorana modes in minimal Kitaev chains under finite Zeeman fields offers a natural interface for the Kitaev parity qubit to interact with other spinful systems. Here, we establish such a platform to bridge the parity qubit and a quantum-dot spin qubit, with the effective coupling governed by the spin-dependent delocalization of the Majorana modes. Depending on whether the spin qubit is coupled to one or two chains constituting the parity qubit, the parity-spin coupling exhibits distinct forms: an anisotropic parity-conserving exchange interaction or a nontrivial exchange tensor tunable via the interchain superconducting-phase bias. Leveraging fast spin-qubit manipulation, we further demonstrate universal parity-qubit control, high-fidelity qubit-state readout, and entangling operations between the parity and spin qubits. These results turn the spinful structure of poor-man's Majoranas from a finite-field imperfection into a resource for hybrid quantum control.
ER  -