Mobility edge of the two-dimensional Bose-Hubbard model
Abstract
We analyze the disorder-driven localization of the two-dimensional Bose-Hubbard model by evaluating the full low-energy quasiparticle spectrum via a recently developed fluctuation operator expansion method. For any strength of the local interaction we find a mobility edge that displays an approximately exponential decay with increasing disorder strength. We determine the finite-size scaling collapse and exponents at this critical line finding that the localization of excitations is characterized by weak multifractality and a thermal-like critical gap ratio. A direct comparison to a recent experiment yields an excellent match of the predicted finite-size transition point and scaling of single particle correlations.
- Publication:
-
Physical Review Research
- Pub Date:
- December 2020
- DOI:
- 10.1103/PhysRevResearch.2.042037
- arXiv:
- arXiv:1909.09247
- Bibcode:
- 2020PhRvR...2d2037G
- Keywords:
-
- Condensed Matter - Quantum Gases;
- Condensed Matter - Disordered Systems and Neural Networks;
- Quantum Physics
- E-Print:
- 5+2 pages, 4 figures (added 12 pages Supplemental Material)