%0 Electronic Article
%A Jiang, Zhongyi
%A Geisert, Simon
%A Ihssen, Sören
%A Pop, Ioan M.
%A Ansari, Mohammad H.
%T Enabling full localization of qubits and gates with a multi-mode coupler
%I arXiv
%M FZJ-2025-04664
%D 2025
%X 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.
%K Quantum Physics (quant-ph) (Other)
%K Mesoscale and Nanoscale Physics (cond-mat.mes-hall) (Other)
%K FOS: Physical sciences (Other)
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.48550/ARXIV.2509.26211
%U https://juser.fz-juelich.de/record/1048466