Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flat Topological Bands and Eigenstate Criticality in a Quasiperiodic
  Insulator   The effects of downfolding a Brillouin zone can open gaps and quench the
kinetic energy by flattening bands. Quasiperiodic systems are extreme examples
of this process, which leads to new phases and critical eigenstates. We
analytically and numerically investigate these effects in a two dimensional
topological insulator with a quasiperiodic potential and discover a complex
phase diagram. We study the nature of the resulting eigenstate quantum phase
transitions; a quasiperiodic potential can make a trivial insulator topological
and induce topological insulator-to-metal phase transitions through a unique
universality class distinct from random systems. This wealth of critical
behavior occurs concomitantly with the quenching of the kinetic energy,
resulting in flat topological bands that could serve as a platform to realize
the fractional quantum Hall effect without a magnetic field.

3
The categories of this paper are: physics
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org