 On 26 March 1929 , Rabi received an offer of a lectureship from Columbia , with a good annual salary of $ 3 @,@ 000 . The Dean of Columbia 's Physics Department , George B. Pegram , was looking for a theoretical physicist to teach statistical mechanics and an advanced course in the new subject of quantum mechanics , and Heisenberg had recommended Rabi . Helen was now pregnant , so Rabi needed a regular job , and this job was in New York . He accepted , and returned to the United States in August on the SS President Roosevelt . Rabi became the only Jewish faculty member at Columbia at the time . 
