TY  - EJOUR
AU  - Jiang, Zhongyi
AU  - Geisert, Simon
AU  - Ihssen, Sören
AU  - Pop, Ioan M.
AU  - Ansari, Mohammad H.
TI  - Enabling full localization of qubits and gates with a multi-mode coupler
PB  - arXiv
M1  - FZJ-2025-04664
PY  - 2025
AB  - Tunable couplers are a key building block of superconducting quantum processors, enabling high on-off ratios for two-qubit entangling interactions. While crosstalk can be mitigated in idle mode, conventional single-mode couplers lack independent control over interactions in the one- and two-excitation manifolds, leading to unitary errors such as leakage during gate operations. Moreover, even at the nominal decoupled point, residual wavefunction delocalization persists, causing unintended qubit-qubit coupling. Here we propose a multi-mode tunable coupler that enables nonlinear control of interactions across excitation manifolds, achieving a high on-off ratio in the one-excitation manifold while suppressing coupling in the two-excitation manifold. The proposed design also realizes complete localization between qubits, providing perfect isolation at the decoupled point and opening new possibilities for scalable, high-fidelity quantum gates.
KW  - Quantum Physics (quant-ph) (Other)
KW  - Mesoscale and Nanoscale Physics (cond-mat.mes-hall) (Other)
KW  - FOS: Physical sciences (Other)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.48550/ARXIV.2509.26211
UR  - https://juser.fz-juelich.de/record/1048466
ER  -