Computing with Quantum Cats Read Free Page A

expected to pass. Alan was desperate not to see his friend go on to Cambridge without him. He decided to take the scholarship examination at the same time, even though he was still only seventeen and Trinity was the top college in Britain (arguably, in the world) for the study of math and science, with a correspondingly high admission standard. The examinations were held over a week in Cambridge, giving the two Shirburnians a chance to live the life of undergraduates, and to meet new people, including Maurice Pryce, another candidate, whom Alan would meet again when their paths crossed in Princeton a few years later.
    The outcome was as Alan had feared. Morcom passed, gaining a scholarship to Trinity that gave him sufficient income to live on as an undergraduate. Alan did not, and faced a separation of at least a year from his first love. But the separation became permanent when Morcom died, of tuberculosis, on February 13, 1930. Alan wrote to his own mother: “I feel that I shall meet Morcom again somewhere and that there will be some work for us to do together…. Now that I am left to do it alone I must not let him down.” And in the spirit of doing the work that they might have done together, or that Morcom might have done alone, and “not letting him down,” Alan tried once again for Cambridge in 1930. Once again, he failed to obtain a Trinity scholarship; but this time he was offered a scholarship worth £80 a year at his second choice of college, King's. He started there in 1931, when he was nineteen.
    CAMBRIDGE…
    Turing managed the unusual feat of joining in both the sporting life (as a runner and rower) and the academic life in Cambridge, while never quite fitting in anywhere socially. He also enjoyed at least one homosexual relationship, with another math student, James Atkins. But it is his mathematical work that is important here. Turing's parting gift from Sherborne, in the form of a prize for his work, had been the book Mathematical Foundations of Quantum Mechanics , by the Hungarian-born mathematician John von Neumann, who would soon play a personal part in Turing's story. 3 In an echo of his early days at Sherborne, not long after he arrived in Cambridge Turing independently came up with a theorem previously (unbeknown to him) proven by the Polish mathematician Wacław Sierpiński; when Sierpiński's priority was pointed out to him, he was delighted to find that his proof was simpler than that of the Pole. Polish mathematicians would also soon loom large in Turing's life.
    In the early 1930s, the structure of the mathematics course in Cambridge was changing. Everybody who entered in 1931 (eighty-five students in all) took two key examinations, Part I at the end of the first year and Part II at the end of the third year. So-called “Schedule A” students left it at that, which was sufficient to gain them their degrees. But “Schedule B” students, including Turing, took a further, more advanced, examination, also at the end of their third year. For the intake which followed Turing's year, the extra examination was taken after a further (fourth) year of study, as it has been ever since: it became known as Part III , and is now roughly equivalent to a Master's degree from other universities.
    This peculiarity of the Cambridge system partly explainswhy Turing never worked for a PhD in Cambridge. Having passed his examinations with flying colors, he was offered a studentship worth £200 which enabled him to stay on at Cambridge for a year to write a dissertation with which he hoped to impress the authorities sufficiently to be awarded a fellowship at King's. In the spring of 1935, still only twenty-two years old, Turing was indeed elected as a Fellow of King's for three years, with the prospect of renewal for at least a further three years, at a stipend of £300 per year; the success was sufficiently remarkable that the boys at Sherborne were given a half-day