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arXiv · 2001.03167

Local Integrals of Motion for Topologically Ordered Many-Body Localized Systems

Thorsten B. Wahl·Benjamin Béri
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Abstract

Many-body localized (MBL) systems are often described using their local integrals of motion, which, for spin systems, are commonly assumed to be a local unitary transform of the set of on-site spin-z operators. We show that this assumption cannot hold for topologically ordered MBL systems. Using a suitable definition to capture such systems in any spatial dimension, we demonstrate a number of features, including that MBL topological order, if present: (i) is the same for all eigenstates; (ii) is robust in character against any perturbation preserving MBL; (iii) implies that on topologically nontrivial manifolds a complete set of integrals of motion must include nonlocal ones in the form of local-unitary-dressed noncontractible Wilson loops. Our approach is well suited for tensor-network methods, and is expected to allow these to resolve highly-excited finite-size-split topological eigenspaces despite their overlap in energy. We illustrate our approach on the disordered Kitaev chain, toric code, and X-cube model.

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BibTeXRIS

Thorsten B. Wahl, Benjamin Béri. 2020-01-09. Local Integrals of Motion for Topologically Ordered Many-Body Localized Systems. https://doi.org/10.1103/physrevresearch.2.033099

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