QQ̄ potential from AdS - CFT relation at T ≥ 0 : Dependence on orientation in internal space and higher curvature corrections

Within the classical approximation we calculate the static Q ¯ Q potential via the AdS/CFT relation for nonzero temperature and arbitrary internal orientation of the quarks. We use a higher order curvature corrected target space background. For timelike Wilson loops there arises a critical line in the orientation-distance plane which is shifted to larger distances relative to the calculation with uncorrected background. Beyond that line there is no Q ¯ Q-force. The overall vanishing of the force for antipodal orientation known from zero temperature remains valid. The spacelike Wilson loops yield a string tension for a (2+1)-dimensional gauge theory, independent of the relative internal orientation, but sensitive to the background correction.