Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Large Negative Electronic Compressibility of LaAlO3-SrTiO3 Interfaces
  with Ultrathin LaAlO3 Layers
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys