2. Drain beans, put them in a pot and add the chicken stock, carrot, celery and enough water to cover the beans by an inch or so.
3. Bring to a simmer uncovered over medium-high heat. Do not boil. Skim off any foam that comes to the surface. (Do not add salt because it will prevent the beans from becoming tender.)
4. When the beans are tender, about 1 hour, remove from heat. Drain and discard the carrot and celery. Set beans aside. (The cannellini beans can be cooked ahead of time, covered and refrigerated up to 3 days.)
5. In a large skillet, heat olive oil over medium heat, add the garlic and cook for 1 minute.
6. Add the beans, season with salt and pepper, and heat thoroughly.
7. Turn off the heat and gently fold in the arugula leaves.
8. Preheat the broiler.
9. Season the lamb chops with salt and pepper.
10. Place the lamb chops on a broiler pan and broil 3 inches from the heat for 4 to 5 minutes. Turn and broil for an additional 3 minutes for medium rare, or 5 minutes for medium.
11. Place 2 lamb chops on each plate and serve with the white beans and arugula.
NOTE: The beans can be cooked ahead of time, covered and refrigerated. To soak the beans quickly, place them in a pot of water, bring to a boil and turn off the heat. Let them stand for 1 hour and proceed with Step 2.