Why information did president Truman keep Stalin at he Potsdam conference?

At the Potsdam Conference in July-August 1945, President Harry S. Truman aimed to assert U.S. interests and discuss post-war Europe with Joseph Stalin. Truman withheld information about the successful testing of the atomic bomb, believing it could give the U.S. leverage in negotiations with the Soviet Union. He sought to contain Soviet expansion and ensure a stable post-war order, while also trying to project strength to both Stalin and other Allied leaders. Ultimately, Truman's approach reflected a mix of diplomacy and a desire to maintain U.S. supremacy in the emerging geopolitical landscape.