Continuous unitary transformations using tensor network representations access the full many-body localized spectrum

Physical review. B./Physical review. B, vol. 114

Abstract

We develop variational continuous unitary transformations (VCUTs), which integrate Wegner-Wilson flow equations with tensor network techniques to approximately diagonalize many-body localized (MBL) Hamiltonians. The diagonalizing unitary is represented as a matrix product operator whose bond dimension controls the accuracy. For the disordered Heisenberg chain, VCUTs accurately reproduce the full spectrum across the ergodic-to-MBL crossover at small system sizes and scale to L = 48 sites. Beyond eigenenergies, the method can track the spatial entanglement structure of the diagonalizing unitary U ( l ) at each flow step, enabling identification of local integrals of motion deep in the MBL phase.

Authors 4

1. Anonymous

   Technische Universität Braunschweig

   Affiliation as printed

   Technische Universität Braunschweig

2. Jan-Niklas Herre Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

3. Dante Marvin Kennes Aachen

   RWTH Aachen University · Max Planck Institute for the Structure and Dynamics of Matter

   Affiliation as printed

   Max Planck Institute for the Structure and Dynamics of Matter

   RWTH Aachen University

4. Christoph Karrasch

   Technische Universität Braunschweig

   Affiliation as printed

   Technische Universität Braunschweig