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arXiv · 2606.23467

Prethermal rotating-frame solid echo in a dipolar nuclear-spin network

Quentin Reynard-Feytis·William Beatrez·Leo Joon Il Moon·Emanuel Druga·Ashok Ajoy
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Abstract

Floquet prethermalization can endow interacting quantum solids with long-lived, approximately conserved quantities, enabling Hamiltonian engineering and new dynamical probes. Using a hyperpolarized network of dipolar-coupled $^{13}$C nuclear spins in diamond driven by pulsed spin-locking, we access a rotating-frame prethermal plateau with quasi-conserved transverse magnetization and cycle-resolved inductive readout. Within this prethermal manifold we observe a robust \emph{rotating-frame solid echo}: after an apparent decay of the rotating-frame free-induction signal over a delay $\tau$, the magnetization revives at time $2\tau$ following a single $(\alpha)_y$ pulse, with maximum amplitude near $\alpha\simeq\pi/2$. The echo envelope decays as a stretched exponential with characteristic time $T_2'\approx 13\,$ms. Analytical arguments and toy-model simulations attribute the revival to Floquet micromotion that transfers coherences between operator subspaces, so that only a subset of the many-body dephasing dynamics is inverted by the $y$ pulse. These results translate classic echo physics into the prethermal rotating frame and point to continuously interrogated prethermal spin ensembles as a versatile platform for high-throughput spectroscopy, Hamiltonian engineering, and long-duration quantum sensing.

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Quentin Reynard-Feytis, William Beatrez, Leo Joon Il Moon, Emanuel Druga, Ashok Ajoy. 2026-06-22. Prethermal rotating-frame solid echo in a dipolar nuclear-spin network. https://arxiv.org/abs/2606.23467

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