For generations, the heat that silently throttles our most powerful machines has resisted precise control, spreading through materials the way rumor spreads through a crowd — diffuse, ungoverned, wasteful. Researchers at UCLA have now demonstrated that in boron arsenide, heat can be coaxed to travel in focused, wave-like pathways at ordinary room temperature, a behavior physicists had only witnessed near absolute zero. This discovery, published in Nature Physics, does not merely refine an engineering parameter — it reframes what thermal energy is allowed to do, and by extension, what our devic