WASHINGTON — Qatar on Monday signed a document to participate in a U.S.-led coalition for supply chain cooperation on artificial intelligence (AI), critical minerals and other areas, joining South Korea and six other signatories to the group. The State Department said that Under Secretary of State for Economic Affairs Jacob Helberg and Qatar's Minister of State for Foreign Trade Affairs Ahmed bin Mohammed Al-Sayed signed Doha's accession to "Pax Silica," an economic security initiative that was launched last month as Washington seeks to counter China's growing heft in advanced technologies. With Qatar's entry, the coalition now consists of eight members: the United States, South Korea, Japan, Australia, Britain, Israel and Singapore. "Together, the United States of America and Qatar affirm a new geopolitical consensus that economic security is national security, and national security is economic security," the department said in a media note. "Qatar's leadership and commitment to investing in secure energy, advanced technology, and critical minerals supply chains make it an indispensab