Dynamical signatures of thermal spin-charge deconfinement in the doped Ising model

The mechanism underlying charge transport in strongly correlated quantum systems, such as doped antiferromagnetic Mott insulators, remains poorly understood. Here, we study the expansion dynamics of an initially localized hole inside a two-dimensional (2D) Ising antiferromagnet at variable temperature. Using a combination of classical Monte Carlo and truncated-basis methods, we reveal two dynamically distinct regimes: a spin-charge confined region below a critical temperature T*, characterized by slow spreading, and a spin-charge deconfined region above T*, characterized by an unbounded diffusive expansion. The deconfinement temperature T* ti 0.65Jz we find is around the N??el temperature TN = 0.567Jz of the Ising background in 2D, but we expect T* < TN in higher dimensions. In both regimes we find that the mobile hole does not thermalize with the Ising spin background on the considered time scales, indicating weak effective coupling of spin and charge degrees of freedom. Our results can be qualitatively understood by an effective parton model and can be tested experimentally in state-of-the-art quantum gas microscopes.

Automated summary

The expansion dynamics of an initially localized hole inside a two-dimensional Ising antiferromagnet were studied using classical Monte Carlo and truncated-basis methods. Two dynamically distinct regimes were revealed: a confined region characterized by slow spreading below a critical temperature, and a deconfined region characterized by unbounded diffusive expansion above the critical temperature. The weak effective coupling between spin and charge degrees of freedom was observed, indicating a lack of thermalization between the mobile hole and the Ising spin background.