English

Non-equilibrium phase diagram of a 1D quasiperiodic system with a single-particle mobility edge

Disordered Systems and Neural Networks 2017-12-06 v3 Mesoscale and Nanoscale Physics Statistical Mechanics Quantum Physics

Abstract

We investigate and map out the non-equilibrium phase diagram of a generalization of the well known Aubry-Andr\'e-Harper (AAH) model. This generalized AAH (GAAH) model is known to have a single-particle mobility edge which also has an additional self-dual property akin to that of the critical point of AAH model. By calculating the imbalance, we get hints of a rich phase diagram. We find a fascinating connection between single particle wavefunctions near the mobility edge of GAAH model and the wavefunctions of the critical AAH model. By placing this model far-from-equilibrium with the aid of two baths, we investigate the open system transport via system size scaling of non-equilibrium steady state (NESS) current. Current is calculated by fully exact non-equilibrium Green's function (NEGF) formalism. The critical point of the AAH model now generalizes to a 'critical' line separating regions of ballistic and localized transport. Like critical point of AAH model, current scales sub-diffusively with system size on the 'critical' line (IN2±0.1I\sim N^{-2\pm0.1}). However, remarkably, the scaling exponent on this line is distinctly different from that obtained for the critical AAH model (where IN1.4±0.05I\sim N^{-1.4\pm0.05}). All these results can be understood from the above-mentioned connection between states near mobility edge of GAAH model and those of critical AAH model. A very interesting high temperature non-equilibrium phase diagram of the GAAH model emerges from our calculations.

Keywords

Cite

@article{arxiv.1707.03749,
  title  = {Non-equilibrium phase diagram of a 1D quasiperiodic system with a single-particle mobility edge},
  author = {Archak Purkayastha and Abhishek Dhar and Manas Kulkarni},
  journal= {arXiv preprint arXiv:1707.03749},
  year   = {2017}
}