Strong coupling of a Gd${}^{3+}$ multilevel spin system to an on-chip superconducting resonator

Abstract

We report the realization of a strong coupling between a Gd${}^{3+}$ spin ensemble hosted in a scheelite (CaWO${}_4$) single crystal and the resonant mode of a coplanar stripline superconducting cavity leading to a large separation of spin-photon states of 146 MHz. The interaction is well described by the Dicke model and the crystal-field Hamiltonian of the multilevel spin system. We observe a change of the crystal-field parameters due to the presence of photons in the cavity that generates a significant perturbation of the crystal ground state. Using finite-element calculations, we numerically estimate the cavity sensing volume as well as the average spin-photon coupling strength of $g_0\approx$ 620 Hz. Lastly, the dynamics of the spin-cavity states are explored via pulsed measurements by recording the cavity ring-down signal as a function of pulse length and amplitude. The results indicate a potential method to initialize this multilevel system in its ground state via an active cooling process.

References in corpus (9)

• Quantum technologies with hybrid systems
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• Anisotropic rare-earth spin ensemble strongly coupled to a superconducting resonator
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• Electron spin ensemble strongly coupled to a three-dimensional microwave cavity
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• Coherent spin dynamics in gadolinium-doped CaWO4 crystal
• High-cooperativity coupling of a rare-earth spin ensemble to a superconducting resonator using yttrium orthosilicate as a substrate
• On-Chip Detection of Electronuclear Transitions in the ${}^{155,157}$Gd Multilevel Spin System

Cited by in corpus (1)

• Precision Multi-Mode Microwave Spectroscopy of Paramagnetic and Rare-Earth Ion Spin Defects in Single Crystal Calcium Tungstate