Planarization of Trimon Processors for On-Chip Integration and Scaling

Trimon processors are multimode superconducting devices that host three mutually coupled qubit modes with a shared dispersive readout, enabling native all-to-all interactions in a compact circuit. To date, most Trimon demonstrations have relied on 3D cavity implementations, which limit scaling to larger multi-qubit architectures [1,2]. To enable on-chip elements that can enhance coherence and control—such as Purcell filters and tunable couplers—a planar realization is therefore desirable. Here, we investigate a planar "pedal Trimon" design that breaks the rotational ring symmetry of the original 3D Trimon while preserving its key Hamiltonian features, namely three anharmonic modes with native three-body couplings. We show that this planar layout retains Trimon-like operating characteristics while providing a geometry more amenable to on-chip microwave engineering and scalable superconducting quantum processors.