Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-temperature illumination and annealing of ultra-high quality quantum
  wells   The effects of low temperature illumination and annealing on fractional
quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are
investigated. Illumination alone, below 1 K, decreases the density of the 2DEG
electrons by more than an order of magnitude and resets the sample to a
repeatable initial state. Subsequent thermal annealing at a few Kelvin restores
the original density and dramatically improves FQH characteristics. A reliable
illumination and annealing recipe is developed that yields an energy gap of 600
mK for the 5/2 state.

0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc