Topologically Protected Edge States in a Single Flux Qubit

@misc{perezfernandez2026topologically,
  title = {{Topologically Protected Edge States in a Single Flux Qubit}},
  author = {Pablo Perez-Fernandez and Manuel Pino},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.42114},
  eprint = {2610.42114},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.42114},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Topologically Protected Edge States in a Single Flux Qubit
AU  - Pablo Perez-Fernandez
AU  - Manuel Pino
PY  - 2026
DA  - 2026/10/30
PB  - arXiv
DO  - 10.48550/arxiv.2610.42114
UR  - https://arxiv.org/abs/2610.42114
AB  - We show that topological edge states can be realized in a simple superconducting circuit composed of an inductively shunted flux qubit. The Josephson potential of that qubit forms a honeycomb lattice similar to the case of graphene. The additional shunting element produces a quartic potential along one flux direction, which effectively creates a boundary in flux space. We map analytically the low-energy dynamics of the circuit to an extended Su--Schrieffer--Heeger (SSH) chain, in which a quartic potential is added to the usual SSH Hamiltonian. This mapping is confirmed by numerical simulations of the full superconducting circuit. We argue that chiral symmetry still holds for the edge states of the extended model around a chiral point in parameter space. Close to this point, we numerically find that edge states in our superconducting circuit are topologically protected against perturbations that obey chiral symmetry, as is the case for charge noise. Our results show that topological effects previously thought to occur in multi-qubit systems, such as protection against decoherence, can also be found in much simpler single superconducting qubits.
ER  -