  We show the generation of two-dimensional quantum turbulence through
simulations of a giant vortex decay in a trapped Bose-Einstein condensate.
While evaluating the incompressible kinetic energy spectra of the quantum fluid
described by the Gross-Pitaevskii equation, a bilinear form in a log-log plot
is verified. A characteristic scaling behavior for small momenta shows
resemblance to the Kolmogorov $k^{-5/3}$ law, while for large momenta it
reassures the universal behavior of the core-size $k^{-3}$ power-law. This
indicates a mechanism of energy transportation consistent with an inverse
cascade. The feasibility of the described physical system with the currently
available experimental techniques to create giant vortices opens up a new route
to explore quantum turbulence.
