Abstract
Quantum entanglement may have various origins ranging from solely interaction-driven quantum correlations to single-particle effects. Here, we explore the dependence of entanglement on time-dependent single-particle basis transformations in fermionic quantum many-body systems, thus aiming at isolating single-particle sources of entanglement growth in quench dynamics. Using exact diagonalization methods, for paradigmatic non-integrable models we compare to the standard real space cut various physically motivated bipartitions. Moreover, we search for a minimal entanglement basis using local optimization algorithms, which at short to intermediate post-quench times yields a significant reduction of entanglement beyond a dynamical Hartree-Fock solution. In the long-time limit, we identify an asymptotic universality of entanglement for weakly interacting systems, as well as a cross-over from dominant real-space to momentum-space entanglement in Hubbard-models undergoing an interaction quench. Finally, we discuss the relevance of our findings for the development of tensor network based algorithms for quantum dynamics.
Highlights
Quantum entanglement may have various origins ranging from solely interaction-driven quantum correlations to single-particle effects
The purpose of this Rapid Communication is to investigate how the single-particle content of entanglement in quantum quench dynamics can be isolated from genuine many-body complexity, thereby revealing physically distinct sources of quantum correlations
We focus on ν = 1/3 in the following, where the model (6) at zero temperature is known to stay in a metallic Luttinger liquid phase up to large V > 0 [44], and has been found to exhibit strongly ergodic behavior [45]
Summary
Quantum entanglement may have various origins ranging from solely interaction-driven quantum correlations to single-particle effects. As we exemplify for several nonintegrable fermionic quantum many-body systems, for quite long transient times the entanglement entropy exhibits a significant basis dependence [see Fig. 1(b)].
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