Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum states of neutrons in the gravitational field and limits for
  non-Newtonian interaction in the range between 1 micron and 10 microns   Quantum states in the Earth's gravitational field can be observed, when
ultra-cold neutrons fall under gravity. In an experiment at the Institut
Laue-Langevin in Grenoble, neutrons are reflected and trapped in a
gravitational cavity above a horizontal mirror. The population of the ground
state and the lowest states follows, step by step, the quantum mechanical
prediction. An efficient neutron absorber removes the higher, unwanted states.
The quantum states probe Newtonian gravity on the micrometer scale and we place
limits for gravity-like forces in the range between 1 micron and 10 microns.

16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin