Geometry and Topology of the space of K\"ahler metrics on singular varieties

Let $Y$ be a compact K"ahler normal space and $\alpha \in H^{1,1}(Y,$\mathbb{R}$)$ a K"ahler class. We study metric properties of the space ${\mathcal{H}}_{\alpha }$ of K"ahler metrics in $\alpha$ using Mabuchi geodesics. We extend several results by Calabi, Chen, Darvas previously established when the underlying space is smooth. As an application we analytically characterize the existence of K"ahler-Einstein metrics on $\mathbb{Q}$-Fano varieties, generalizing a result of Tian, and illustrate these concepts in the case of toric varieties.