For theoretical understanding of quarkonium production in heavy ion collisions
it is important to know the potential between the heavy quark and anti-quark
at non-zero temperature. This potential is complex and provides an efficient
way to calculate quarkonium spectral functions at non-zero temperature and
an important input for dynamical models aiming to describe quarkonium
production in heavy ion collisions (see e.g. ).
I report on the lattice calculations of the heavy quark potential at T>0
in 2+1 flavor QCD at physical quark masses using Highly Improved Staggered
Quark formulation. The gauge configurations needed for the high statistics
study of the heavy quark potential have been generated by HotQCD and TUMQCD
collaborations . In this study lattices with temporal extent $N_t=12$ and $16$
are used and the real and imaginary part of the potential are obtained using the
moments of the temporal Wilson loops. I study in detail the systematic effects in the determination of the real and the imaginary parts of the potential when using the moment method. It turns out that below the transition temperature the imaginary part is consistent
with zero, while above the transition temperature it increases with increasing temperature and separation between the quark and anti-quark till the signal diminishes.
The real part of the potential is similar to the zero temperature one for distances smaller than 0.8fm and temperatures smaller than 250 MeV. This analysis significantly extends the preliminary work presented in .
I will also discuss the implications of these findings for existence of heavy quark bound
state in QGP by calculating the corresponding meson spectral functions with the newly determined potential.
 P. Petreczky and C. Young, Sequential bottomonium production at high temperatures, arXiv:1606.08421 [nucl-th]
 A. Bazavov et al (HotQCD), Phys. Rev. D90 (2014) 094503
 A. Bazavov, Y. Burnier and P. Petreczky, Nucl. Phys. A932 (2014) 117