Experimental Realization and Phase-Space Winding of a Topological Defect State in the Quantum Rabi Model

Abstract:We experimentally realize a topological defect state of the quantum Rabi model in a single trapped $^{171}\mathrm{Yb}^{+}$ ion. The state is supported by a tunable interface arising from the oscillator's intrinsic number-dependent coupling in the Fock-state-lattice representation. We independently prepare the state at each sideband-phase setting and reconstruct its motional phase-space distribution using characteristic-function tomography. The resulting Wigner-centroid trajectories exhibit winding numbers of one and zero in the two coupling regimes. Changing the carrier amplitude rescales the trajectories while preserving their windings. Carrier-amplitude modulation provides a complementary dynamical probe, yielding a spin response consistent with the excitation gaps and accessible transition channels from the defect state. The experiment connects topological defect-state physics in a nonuniform synthetic lattice to the measurable phase-space geometry of a hybrid spin-boson system.

arXiv:2609.34389 [quant-ph]

(or arXiv:2609.34389v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.34389 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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