Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum-enhanced sensing using non-classical spin states of a highly
  magnetic atom   Coherent superposition states of a mesoscopic quantum object play a major
role in our understanding of the quantum to classical boundary, as well as in
quantum-enhanced metrology and computing. However, their practical realization
and manipulation remains challenging, requiring a high degree of control of the
system and its coupling to the environment. Here, we use dysprosium atoms - the
most magnetic element in its ground state - to realize coherent superpositions
between electronic spin states of opposite orientation, with a mesoscopic spin
size J=8. We drive coherent spin states to quantum superpositions using
non-linear light-spin interactions, observing a series of collapses and
revivals of quantum coherence. These states feature highly non-classical
behavior, with a sensitivity to magnetic fields enhanced by a factor 13.9(1.1)
compared to coherent spin states - close to the Heisenberg limit 2J=16 - and an
intrinsic fragility to environmental noise.

16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci