  The entropy of entanglement between a three-dimensional slab of thickness l
and its complement is studied numerically for four-dimensional SU(2) lattice
gauge theory. We find a signature of a nonanalytic behavior of the entanglement
entropy, which was predicted recently for large N_c confining gauge theories in
the framework of AdS/CFT correspondence. The derivative of the entanglement
entropy over l is likely to have a discontinuity at some l = l_c. It is argued
that such behavior persists even at finite temperatures, probably turning into
a sort of crossover for temperatures larger than the temperature of the
deconfinement phase transition. We also confirm that the entanglement entropy
contains quadratically divergent l-independent term, and that the nondivergent
terms behave as the inverse square of l at small distances.
