Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental realization of strong effective magnetic fields in an
  optical lattice   We use Raman-assisted tunneling in an optical superlattice to generate large
tunable effective magnetic fields for ultracold atoms. When hopping in the
lattice, the accumulated phase shift by an atom is equivalent to the
Aharonov-Bohm phase of a charged particle exposed to a staggered magnetic field
of large magnitude, on the order of one flux quantum per plaquette. We study
the ground state of this system and observe that the frustration induced by the
magnetic field can lead to a degenerate ground state for non-interacting
particles. We provide a measurement of the local phase acquired from
Raman-induced tunneling, demonstrating time-reversal symmetry breaking of the
underlying Hamiltonian. Furthermore, the quantum cyclotron orbit of single
atoms in the lattice exposed to the magnetic field is directly revealed.

12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph