Complex Heavy-Quark Potential at Finite Temperature from Lattice QCD
  We calculate for the first time the complex potential between a heavy quark and antiquark at finite temperature across the deconfinement transition in lattice QCD. The real and imaginary part of the potential at each separation distance $r$ is obtained from the spectral function of the thermal Wilson loop. We confirm the existence of an imaginary part above the critical temperature $T_C$, which grows as a function of $r$ and underscores the importance of collisions with the gluonic environment for the melting of heavy quarkonia in the quark-gluon-plasma. 
Alexander Rothkopf, Tetsuo Hatsuda, Shoichi Sasaki
hep-lat hep-ph nucl-th