In the famous monograph "Many body physics" by Mahan there is a statement about the corresponding relation between the zero temperature and the ground state:
"Furthermore,the zero temperature property of a system is an important conceptual quantity--the ground state of an interacting system."
As far as I know the ground state represents the lowest eigenenergy for our system obtained by solving Schrodinger equation and hence is a description based on the microscopic viewpoint. However the temperature is a macroscopic parameter for describing our system. How can I understand this statement? What's the relation between both?