Deconfinement transition and string tensions in SU(4) Yang-Mills theory

We present results from numerical lattice calculations of SU(4) Yang-Mills theory. This work has two goals: to determine the order of the finite temperature deconfinement transition on an N-t=6 lattice and to study the string tensions between static charges in the irreducible representations of SU(4). Motivated by the argument of Pisarski and Tytgat that a second-order SU(infinity) deconfinement transition would explain some features of the SU(3) and QCD transitions, we confirm older results on a coarser, N-t=4, lattice. We see a clear two-phase coexistence signal in the order parameter, characteristic of a first-order transition, at 8/g(2)=10.79 on a 6 x 20(3) lattice, on which we also compute a latent heat of Delta epsilon approximate to0.6 epsilon (SB). Computing Polyakov loop correlation functions, we calculate the string tension at finite temperature in the confined phase between fundamental charges sigma (1), between diquark charges sigma (2), and between adjoint charges sigma (4). We find that 1<<sigma>(2)/sigma (1)<2. and our result for the adjoint string tension <sigma>(4) is consistent with string breaking.