Screening and deconfinement of sources in finite temperature SU(2) lattice gauge theory

Deconfinement and screening of higher-representation sources in finite-temperature SU(2) lattice gauge theory is investigated by both analytical and numerical means. The effective Polyakov-line action at strong coupling is simulated by an efficient cluster-updating Monte Carlo algorithm for the case of d\!=\!4 dimensions. The results compare very favourably with an improved mean-field solution. The limit d\!\to\!\infty of the SU(2) theory is shown to be highly singular as far as critical behaviour is concerned. In that limit the leading amplitudes of higher representation Polyakov lines vanish at strong coupling, and subleading exponents become dominant. Each of the higher-representation sources then effectively carry with them their own critical exponents.