Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dual channel self-oscillating optical magnetometer   We report on a two-channel magnetometer based on nonlinear magneto-optical
rotation in a Cs glass cell with buffer gas. The Cs atoms are optically pumped
and probed by free running diode lasers tuned to the D$_2$ line. A wide
frequency modulation of the pump laser is used to produce both synchronous
Zeeman optical pumping and hyperfine repumping. The magnetometer works in an
unshielded environment and spurious signal from distant magnetic sources is
rejected by means of differential measurement. In this regime the magnetometer
simultaneously gives the magnetic field modulus and the field difference.
  Rejection of the common-mode noise allows for high-resolution magnetometry
with a sensitivity of \pthz{2}. This sensitivity, in conjunction with long-term
stability and a large bandwidth, makes possible to detect water proton
magnetization and its free induction decay in a measurement volume of 5 cm$^3$

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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: econ
37
The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph