After his graduation in 1900, Einstein became a naturalized Swiss citizen in 1901 and got a job as a technical assistant at the Swiss patent office in Bern. In 1903, he married his university sweetheart, Mileva Maric. While employed at the patent office, Einstein continued his own investigations in theoretical physics. In 1905, he published an article entitled A New Determination of Molecular Dimensions in the well-known German physics monthly Annalen der Physik. The article earned him a Ph.D. from the University of Zurich. That same year, Einstein published four other papers in Annalen, including his revolutionary theory that light exists in both waves and particles. His major proposal of 1905, however, was his special theory of relativity, which dismissed the traditional notion that time and space were absolute concepts, suggesting instead that both time and space vary with circumstances.