Heavy quark potential at finite imaginary chemical Potential

We investigate chemical-potential (μ) dependence of static-quark free energies in both the real and imaginary μ regions, using the clover-improved two-flavor Wilson fermion action and the renormalization-group improved Iwasaki gauge action. Static-quark potentials are evaluated from the Polyakov-loop correlator in the deconfinement phase and the imaginary μ = iμI region and extrapolated to the real μ region with analytic continuation. As the analytic continuation, the potential calculated at imaginary μ = iμI is expanded into a Taylor-expansion series of iμI=T up to 4th order and the pure imaginary variable imI=T is replaced by the real one μR=T. At real μ, the 4th-order term weakens μdependence of the potential sizably. Also, the color-Debye screening mass is extracted from the color-singlet potential at imaginary μ, and the mass is extrapolated to real μ by analytic continuation. The screening mass thus obtained has stronger μ dependence than the prediction of the leading-order thermal perturbation theory at both real and imaginary μ. This talk is based on [1].