Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct Observation of Coherent Population Trapping in a Superconducting
  Artificial Atom   The phenomenon of Coherent Population Trapping (CPT) of an atom (or solid
state "artificial atom"), and the associated effect of Electromagnetically
Induced Transparency (EIT), are clear demonstrations of quantum interference
due to coherence in multi-level quantum systems. We report observation of CPT
in a superconducting phase qubit by simultaneously driving two coherent
transitions in a $\Lambda$-type configuration, utilizing the three lowest lying
levels of a local minimum of a phase qubit. We observe $60(\pm 7)%$ suppression
of excited state population under conditions of CPT resonance. We present data
and matching theoretical simulations showing the development of CPT in time.
Finally, we used the observed time dependence of the excited state population
to characterize quantum dephasing times of the system.

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The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con