Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational Effects in g Factor Measurements and High-Precision
  Spectroscopy: Limits of Einstein's Equivalence Principle   We study the interplay of general relativity, the equivalence principle, and
high-precision experiments involving atomic transitions and g factor
measurements. In particular, we derive a generalized Dirac Hamiltonian, which
describes both the gravitational coupling for weak fields, as well as the
electromagnetic coupling, e.g., to a central Coulomb field. An approximate form
of this Hamiltonian is used to derive the leading gravitational corrections to
transition frequencies and g factors. The position-dependence of atomic
transitions is shown to be compatible with the equivalence principle, up to a
very good approximation. The compatibility of g factor measurements requires a
deeper, subtle analysis, in order to eventually restore the compliance of g
factor measurements with the equivalence principle. Finally, we analyze small,
but important limitations of Einstein's equivalence principle due to quantum
effects, within high-precision experiments. We also study the relation of these
effects to a conceivable gravitationally induced collapse of a quantum
mechanical wave function (Penrose conjecture), and space-time noncommutativity,
and find that the competing effects should not preclude the measurability of
the higher-order gravitational corrections. Surprisingly large higher-order
gravitational effects are obtained for transitions in diatomic molecules.

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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: cs