Many-body localization in the Heisenberg X X Z magnet in a random field

We numerically investigate Heisenberg $XXZ$ spin-$1∕2$ chain in a spatially random static magnetic field. We find that time-dependent density-matrix renormalization group simulations of time evolution can be performed efficiently, namely, the dimension of matrices needed to efficiently represent the time evolution increases linearly with time and entanglement entropies for typical chain bipartitions increase logarithmically. As a result, we show that for large enough random fields, infinite temperature spin-spin correlation function displays exponential localization in space indicating insulating behavior of the model.

• JA
  Javna Agencija za Raziskovalno Dejavnost RS