The Bethe–Peierls Correspondence

The following sections are included:

• Contents

• Acknowledgements

In August 1927 while enjoying his customary summer holiday with his mother in the Alps, Hans Bethe sent a postcard to Rudolf Peierls, a fellow student at Arnold Sommerfeld's institute¹ of theoretical physics in Munich.² Little did the two students know that their meeting in Munich in 1927 would be the beginning of a deep friendship and a productive work relationship; little, also, did they know that when Hans Bethe, shortly before his friend's death in 1995 would reminisce about their lives³ as those of two of the giants of 20th century physics he would look back on more than 68 years of uninterrupted contact most clearly visible in the hundreds of pages of letters exchanged between the two …

The first card sent from Bethe to Peierls from his vacations in Bad Gastein,¹³ where he had spent the summer shortly after his parents' divorce, is a first indication of one of the common interests of the two young men: a love of the mountains. Neither of them being athletic as such, the two nevertheless enjoyed mountaineering in the summer and skiing in the winter, a passion which they shared with many of their generation of young physicists. And indeed, many of the following letters describe the various alpine adventures, and frequent references are found to the ‘brave men who fearlessly climb the harsh mountains’, an odd phrase that had its origin in a remark of a young boy who saw Bethe, Peierls, and their two friends, Werner Sachs and Hans Thorner, climb some mountains in 1927.¹⁴ …

The years between 1935 and 1940 were a period of consolidation in the careers of both Bethe and Peierls. Hans Bethe had already made a name for himself as one of the masters of theoretical physics. He had written what he considered his best paper, on the stopping power of charged particles as they go through matter, the paper which earned him the habiliation allowing him to teach at German universities.¹⁷⁰ He had written two Handbuch articles on the quantum mechanics of one- and two-electron problems, and (nominally together with Sommerfeld) on the electron theory of metals.¹⁷¹ And together with Wolfgang Heitler, he had written an influential paper on bremsstrahlung and pair production which became a classic.¹⁷² …

After the end of the war, Rudolf Peierls and Hans Bethe returned to their homes at Cornell and the UK. Although Peierls had attractive offers from a number of universities, including Oxford, Manchester, London and Cambridge, he chose to remain at Birmingham.³⁶⁰ He had come to Birmingham in 1937 as the first professor of Mathematical Physics and had set himself the task of establishing a school devoted to both first-class research and first-class teaching. The war had put the effort on hold, but as soon as Peierls returned to Birmingham he re-engaged in the process. Virtually from scratch he built a school of mathematical physics, or theoretical physics as it would be called later, which was arguably the best in the country and which could compete with any in Europe and with most others globally. He had clear ideas of what he regarded as important for a prosperous theoretical physics community in the UK: a balanced flexible system that provided good training and high standards without prejudicing against students outside Oxbridge …

Having been offered the Wykeham Chair of Physics in 1961, Rudolf Peierls, after lengthy negotiations, decided to accept it in early 1962 and he took up his appointment in the autumn of 1963. When asked about the reasons for his decision to move from Birmingham to Oxford, he would later refer to the need for change after quarter of a century at the same university …

The following sections are included:

• In Lieu of a Bibliography

• Name Index