I may have defeated a lifelong struggle with the post-lunch slump. — Fifteen years ago, my afternoons were agony. I was doing my Ph.D. in computer science. After lunch, I was useless: tired, stiff, and unfocused. Coffee, walks, stretching: nothing helped. But since I started working from home, I’ve been tinkering to design the perfect day. It now includes an over-optimized nap. …