ANN ARBOR, Mich. (AP) — A newly constructed University of Michigan facility that will be home to the most powerful laser in the United States is hosting its first experiment this week. Called ZEUS, it is expected to make the U.S. competitive again in the realm of high-power laser facilities. The U.S. built the world’s first petawatt laser a quarter-century ago, but hasn’t kept pace with more ambitious systems in Europe and Asia. ZEUS was awarded $18.5 million by the National Science Foundation to establish it as a federally funded international user facility. It will be a 3-petawatt system. Three petawatts is 3 with 15 zeroes after it.