  We study the canonical quantization of a massless charged scalar field on a
Reissner-Nordstrom black hole background. Our aim is to construct analogues of
the standard Boulware, Unruh and Hartle-Hawking quantum states which can be
defined for a neutral scalar field, and to explore their physical properties by
computing differences in expectation values of the scalar field condensate,
current and stress-energy tensor operators between two quantum states. Each of
these three states has a non-time-reversal-invariant ``past'' and ``future''
charged field generalization, whose properties are similar to those of the
corresponding ``past'' and ``future'' states for a neutral scalar field on a
Kerr black hole. In addition, we present some tentative,
time-reversal-invariant, equilibrium states. The first is a ``Boulware''-like
state which is as empty as possible at both future and past null infinity.
Second, we posit a ``Hartle-Hawking''-like state which may correspond to a
thermal distribution of particles. The construction of both these latter states
relies on the use of nonstandard commutation relations for the creation and
annihilation operators pertaining to superradiant modes.
