  We combine techniques previously utilised to study flux tube field density
profiles and to study the excited spectrum of the gluonic fields produced by a
static quark-antiquark pair. Working with pure gauge SU(3) fields discretised
in a lattice, we utilise Wilson loops with a large basis of gluonic spacelike
Wilson lines to include different excitations of the quark-antiquark flux tube.
To increase the signal over noise ratio, we use the multihit technique in the
temporal Wilson lines and the APE smearing in spatial Wilson lines. The number
of gluonic operators combined with the space points where we compute the flux
tube densities turns out to be very large, and we resort to GPUs and to CUDA
codes. Computing the effective mass plot from the diagonalized correlation
matrix, we separate the excitations with different two-dimensional angular
momentum, parity and radial quantum numbers. We then compute the colour field
density profiles for all the components of the colour electric and colour
magnetic fields. We analyse our results for the first excitations of the flux
tube and search for signals of novel phenomena beyond the Nambu-Goto string
model, such as a longitudinal mode or an explicit gluon.
