Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Nanotesla-level, shield-less, field-compensation-free,
  wave-mixing-enhanced body-temperature atomic magnetometry for biomagnetism
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph