down at regular intervals. John Archibald Wheeler and partner Enrico Fermi suspected that a fission product, Xe-135, with a half-life of 9.4 hours, was the culprit, and might be a neutron poison or absorber. Segrè then remembered the 1940 PhD thesis that Wu had done for him at Berkeley on the radioactive isotopes of Xe and told Fermi to "ask Ms. Wu". The paper on the subject was still unpublished, but after Fermi contacted Wu, Segrè visited her dorm room together with Nichols and collected the typewritten draft prepared for the Physical Review. The suspicions of Fermi and Wheeler came true, Wu's paper unknowingly verified that Xe-135 was indeed the culprit for the B Reactor; it turned out to have an unexpectedly large neutron absorption cross-section. Wu, wary of her publication giving information to other nations on the arms race of the war, waited for a few months before November 1944, when she and Segrè submitted a complete study on these results, which was published months before the bombs were used the next year. Wu also used her findings in radioactive uranium separation to build the standard model for producing enriched uranium to fuel the atomic bombs at the Oak Ridge, Tennessee facility as well as build innovative Geiger counters. Wu, like most involved physicists in their later years, distanced herself from the Manhattan Project due to its destructive outcome and recommended to the Taiwanese president Chiang Kai-shek in 1962 to never build nuclear weapons. However, she was pleased to know that her family was safe in China. Years later, Wu in a rare occasion opened up on her involvement in building the bomb,Do you think that people are so stupid and self-destructive? No. I have confidence in humankind. I believe we will one day live together peacefully. Famous early experiments and academic leading career After the end of the war in August 1945, Wu accepted an offer of a position as an associate research professor at Columbia. She would remain at Columbia for the rest of her career, and was first named associate professor in 1952, which made her the first woman to become a tenured physics professor in university history. In November 1949, Wu experimented with the conclusions of Einstein's EPR thought experiment, which called quantum entanglement "spooky action at a distance". Wu was the first to establish the phenomenon and validity of entanglement using photons through observing