  The classical, relativistic thin-disk theory of Novikov and Thorne (NT)
predicts a maximum accretion efficiency of 40% for an optically thick,
radiatively efficient accretion disk around a maximally spinning black hole
(BH). However, when a strong magnetic field is introduced to numerical
simulations of thin disks, large deviations in efficiency are observed, in part
due to mass and energy carried by jets and winds launched by the disk or BH
spin. The total efficiency of accretion can be significantly enhanced beyond
that predicted by NT but it has remained unclear how the radiative component is
affected. In order to study the effect of a dynamically relevant large-scale
magnetic field on radiatively efficient accretion, we have performed numerical
3D general relativistic - radiative - magnetohydroynamic (GRRMHD) simulations
of a disk with scale height to radius ratio of $H/R~0.1$ around a moderately
spinning BH (a=0.5) using the code HARMRAD. Our simulations are fully global
and allow us to measure the jet, wind, and radiative properties of a
magnetically arrested disk (MAD) that is kept thin via self-consistent
transport of energy by radiation using the M1 closure scheme.
  Our fiducial disk is MAD out to a radius of ~16R_g and the majority of the
total ~13\% efficiency of the accretion flow is carried by a magnetically
driven wind. We find that the radiative efficiency is slightly suppressed
compared to NT, contrary to prior MAD GRMHD simulations with an ad hoc cooling
function, but it is unclear how much of the radiation and thermal energy
trapped in the outflows could ultimately escape.
