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arXiv · 1711.01840

Interplay of charge and spin dynamics after an interaction quench in the Hubbard model

Marcin M. Wysokinski·Michele Fabrizio
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Abstract

We investigate the unitary dynamics following a sudden increase $ΔU>0$ of repulsion in the paramagnetic sector of the half-filled Hubbard model on a Bethe lattice, by means of a variational approach that combines a Gutzwiller wavefunction with a partial Schrieffer-Wolff transformation, both defined through time-dependent variational parameters. Besides recovering at $ΔU_c$ the known dynamical transition linked to the equilibrium Mott transition, we find pronounced dynamical anomaly at larger $ΔU_*>ΔU_c$ manifested in a singular behaviour of the long-time average of double occupancy. Although the real-time dynamics of the variational parameters at $ΔU_*$ strongly resembles the one at $ΔU_c$, careful frequency spectrum analysis suggests a dynamical crossover, instead of a dynamical transition, separating regions of a different behaviour of the spin-exchange.

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Marcin M. Wysokinski, Michele Fabrizio. 2017-11-06. Interplay of charge and spin dynamics after an interaction quench in the Hubbard model. https://doi.org/10.1103/physrevb.96.201115

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