  Light bridges are the most prominent manifestation of convection in sunspots.
The brightest representatives are granular light bridges composed of features
that appear to be similar to granules. An in-depth study of the convective
motions, temperature stratification, and magnetic field vector in and around
light bridge granules is presented with the aim of identifying similarities and
differences to typical quiet-Sun granules. Spectropolarimetric data from the
Hinode Solar Optical Telescope were analyzed using a spatially coupled
inversion technique to retrieve the stratified atmospheric parameters of light
bridge and quiet-Sun granules. Central hot upflows surrounded by cooler fast
downflows reaching 10 km/s clearly establish the convective nature of the light
bridge granules. The inner part of these granules in the near surface layers is
field free and is covered by a cusp-like magnetic field configuration. We
observe hints of field reversals at the location of the fast downflows. The
quiet-Sun granules in the vicinity of the sunspot are covered by a low-lying
canopy field extending radially outward from the spot. The similarities between
quiet-Sun and light bridge granules point to the deep anchoring of granular
light bridges in the underlying convection zone. The fast, supersonic downflows
are most likely a result of a combination of invigorated convection in the
light bridge granule due to radiative cooling into the neighboring umbra and
the fact that we sample deeper layers, since the downflows are immediately
adjacent to the slanted walls of the Wilson depression.
