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arXiv · 2602.02433

Nonlinear light cone spreading of correlations in a triangular quantum magnet: a hard quantum simulation target

A. Scheie·J. Willsher·E. A. Ghioldi·Kevin Wang·P. Laurell·J. E. Moore·C. D. Batista·J. Knolle·D. Alan Tennant
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Abstract

Dynamical correlations of quantum many-body systems are typically analyzed in the momentum space and frequency basis. However, quantum simulators operate more naturally in real space, real time settings. Here we analyze the real-space time-dependent van Hove spin correlations $G(r,t)$ of the 2D triangular antiferromagnet KYbSe$_2$ as obtained from high-resolution Fourier-transformed neutron spectroscopy. We compare this to $G(r,t)$ from five theoretical simulations of the well-established spin Hamiltonian. Our analysis reveals non-linear sub-ballistic low-temperature transport in KYbSe$_2$ which none of the current state-of-the-art numerical or field-theoretical methods reproduce. Our observation signals an emergent collective hydrodynamics, perhaps associated with the quantum critical phase of a quantum spin liquid, and provides an ideal benchmark for future quantum simulations.

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A. Scheie, J. Willsher, E. A. Ghioldi, Kevin Wang, P. Laurell, J. E. Moore, C. D. Batista, J. Knolle, D. Alan Tennant. 2026-02-02. Nonlinear light cone spreading of correlations in a triangular quantum magnet: a hard quantum simulation target. https://arxiv.org/abs/2602.02433

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