Combine pomegranate juice, wine, sugar, cinnamon stick, and cloves in a large saucepan. Cover, bring to a boil, reduce heat and simmer, stirring until sugar dissolves.
Meanwhile peel pears, leaving stem attached. Using a melon baller (or metal spoon) core the bottom of the pear.
Add pears, orange zest, and orange slices to the saucepan, return to a simmer, cover and cook 15 to 20 minutes, turning pears occasionally, until tender when pierced in thickest part.
Cool pears in saucepan, then transfer with poaching liquid to a container. Cover and refrigerate until chilled.
As pears are chilling, in a small bowl whip together Greek yogurt, ricotta, and orange zest.
To serve, cut pears in half, top with yogurt mixture, and spoon some poaching liquid around pears.
