The Strange Story of the Quantum
As we saw in the last chapter, Einstein and Mileva were married in January 1903. There is every reason to believe that the marriage began as a happy one and that the couple welcomed the birth of their first son, whom they named Hans Albert, in May 1904. In September of that year Einstein's appointment at the Swiss patent office was upgraded to a permanent position. Einstein did so much fundamental work in physics during this period—writing five superb papers and his Ph.D. thesis in 1905 alone—that it is tempting to think that his job in the patent office was not very time-consuming. But this was not the case.
He took the job of examining applications for patents for inventions very seriously. He enjoyed the work: he liked inventions and inventors. In the late 1920s he even took out several patents himself, registered jointly with the Hungarian physicist Leo Szilard. One of them was for a noiseless refrigerator. It would have worked, but easier methods were found. But around 1905, when Einstein was creating modern physics, he was managing a household with a young son and working full-time in an office. The physics was done in his spare time.