FRAYN’S COPENHAGEN

1. THE AUTHOR characters THE PLAY plot FRAYN’S COPENHAGEN comments HISTORICAL BACKGROUND from the beginnings of modern atomic theory to Hiroshima SCIENTIFIC BACKGROUND

2. MICHAEL FRAYN: biography • English dramatist, columnist, reporter and translator, Michael Frayn was born on September 8, 1933, in the suburbs of London. • Growing up in Ewell, South London, he soon revealed a talent for music and poetry and, by the time he was a teenager, he knew that he wanted to be a writer of some sort. • Frayn attended the University of Cambridge, where he graduated in 1957 with a degree in moral science.

3. MICHAEL FRAYN: biography • He started working as a reporter and a columnist for the Manchester Guardian and The Observer. • He has written several plays for the theatre and Copenhagen is one of them, Frayn has also translated Chekhov, and written some screenplays, including Clockwise, Make and Break and Benefactors which have been filmed for UK television. • He won several prizes for his works. • He is married to the biographer and critic Claire Tomalin and they live in London.

4. THE PLAY:PLOT, CHARACTERS AND COMMENTS Copenhagen, a thought-provoking drama by Michael Frayn, re-enacts the 1941 visit of Werner Heisenberg, who was then in charge of the Nazi nuclear power programme, to Niels Bohr, his mentor and collaborator in creating quantum mechanics, complementarity, and the uncertainty principle, in German – occupied Denmark. The third character in the play is Bohr’s wife Margrethe.

5. Margrethe didn’t like Heisenberg and was particularly suspicious of that meeting in 1941, expressing the view of those who suspected Heisenberg of wrong doing and were hostile in their view of his actions and behaviour. • Frayn has Bohr, his wife Margrethe and Heisenberg re-enact and examine the meeting, discussing, in the process, how science, politics and morality may intertwine. • "Re-enact" is not really the right word, for no one now alive appears to know what actually took place during the visit, and Frayn does not try to solve the mystery. • More historical investigation and speculation than high drama, the events in Copenhagen are driven by a single question: what drove German physicist Werner Heisenberg to visit his former mentor, the half-Jewish Niels Bohr, in occupied Denmark in 1941? • There was a meeting. Why?

6. Was Heisenberg after help with the Nazi nuclear research programme, or seeking information about US and Allied progress on atomic research … or something else? • Did Heisenberg want to warn Bohr, and through him the Allies, that the Germans were working on an atomic bomb and if so to what end? • Was it to convey the impression that Germany was about to succeed and that the Allies should therefore make peace with Hitler… or was it say that he had given up on an impossible task and that therefore the other side shouldn’t try either? • Did Heisenberg want to find out whether the Allies were actually working on an A - bomb? • Or did he hope to convince Bohr to issue a joint declaration with him denouncing efforts to build a bomb and pledging not to work on it?

7. “The idea for Copenhagen came to me out of my interest in philosophy.” Frayn declared in a BBC interview “It was when I read a remarkable book called Heisenberg's War by Thomas Powers, that I came across the story of Werner Heisenberg's visit to Niels Bohr in 1941. As soon as I read it I began to think that this story reflected some of the problems that I had been thinking about in philosophy for a long time. • How do we know why people do what they do, and even how one knows what one does oneself? It's a fundamental question... this is the heart of the play. (…) We can never know everything about human thinking.

8. I wanted to suggest with Copenhagen that there is some kind of parallel between the indeterminacy of human thinking, and the indeterminacy that Heisenberg introduced into Physics with his famous Uncertainty Principle.Though I'm not trying to say they're exactly parallel. • The Uncertainty Principle says that there is no way, however much we improve our instruments, that we can ever know everything about the behaviour of a physical object.And I think it's also true about human thinking.” MICHAEL FRAYN Sources: ·Copenhagen in New York by Harry Lustig and Brian B. Schwartz. · Interview with Michael Frayn, BBC 28.8.2003.

9. AN HISTORICAL PERSPECTIVE ON THE BACKGROUND AND THE CHARACTERS Though the details of their famous meeting may be in dispute, Niels Bohr and Werner Heisenberg are certainly well-documented historical persons, both very much a part of their times. They were intimately involved in the evolution of modern atomic physics. They survived not one but two devastating world wars, and they lived well into the 20th Century under the threat of the Cold War, a war chiefly fought with the terror of nuclear annihilation, whose basic scientific concepts they had helped discover.

10. So, what was Heisenberg trying to tell Bohr during this meeting, and what did he want from Bohr? The broader historical setting and a fuller appreciation of Heisenberg’s outlook and relationship to the war and to fission research strongly suggest that he wanted… • First: to convince Bohr that the seemingly inevitable German victory would not be so bad for Europe after all. The alternative, as Heisenberg later noted to his horrified Dutch colleagues, was a Europe ruled by the Soviet Union. Having witnessed a traumatic Soviet revolution in Bavaria as a teenager, Heisenberg always considered Soviet domination an even worse evil than Nazi domination.

11. Second: he apparently wanted Bohr to use his influence to prevent Allied scientists, who were surely far behind the Germans, from working towards building a bomb that could be used against Germany. Bohr immediately sensed Heisenberg’s intentions and broke off the conversation. Heisenberg returned home to Germany intent on continuing fission research. Heisenberg had already resigned himself to the march of events, and events after the visit to Bohr now appeared to be marching toward a possible nuclear war, regardless of what he may or may not have wanted.

12. However, just three months later, the German Army decided to abandon its fission project on the recommendation of its closest advisors, choosing to concentrate instead on rockets and jet aircraft. It was the beginning of the end of any German hopes for sweeping success in fission research. • Why did the Germans not make an atomic bomb? • Why, as became known as a result of Samuel Goudsmit’s Alsos mission at the end of the War, were they, under Heisenberg, not even trying, but were working instead to build a nuclear reactor for the production of energy? • Was it because of incompetence? • Was Heisenberg dragging his feet or denying the feasibility because he didn’t want Hitler to have the bomb?

13. Who had more on his conscience? Heisenberg? Whose work in nuclear physics during the War did not result in the death of a single human being…or Bohr? Who at Los Alamos contributed to building the atomic bomb, which did kill thousands of people. Bibliography: A historical Perspective on Copenhagen by Dr. David C. Cassidy.

14. SCIENTIFIC BACKGROUND • Frayn’s play is a drama in which Physics (quantum mechanics, atomic physics , etc) is in the background throughout. One merit of Frayn’s play is it makes Physics accessible to the audience. • Bohr’s wife is in the play mostly for this reason, because she had no scientific training and yet her husband discussed all his work with her. She is like our representative there, someone who is not a scientist and to whom everything must be made plain, that means easier for us to be understand.

15. All his life, Niels Bohr struggled as he tried to express his thoughts and put them on paper, either in Danish or English or German. It did not help that he mumbled and often could not be heard, leave alone understood, by his listeners. • Michael Frayn’s play "Copenhagen" admirably conveys the torment that Bohr and his friends put themselves through as they groped their way toward a formulation of quantum mechanics that eventually changed how we do, teach, and learn physics.

16. Bohr won the Nobel Prize in 1922, at age 37, "for his investigations of the structure of atoms and the radiations emanating from them". • In the following years, through the twenties and early thirties, he devoted most of his time and energy to a fuller understanding of the meaning of quantum mechanics. • People began to speak of the "Copenhagen school", the "Copenhagen interpretation" of quantum mechanics, the "Spirit of Copenhagen", and more recently and sometimes unkindly of the "Copenhagen orthodoxy".* *in the student’s book you will find an extract of a lecture on this point given by Professor Eugen Merzbacher - University of North Carolina .

17. Electrons: 1895 Thomson discovers the electron, the extremely light, negatively charged particles orbiting inside the atom which give it its chemical properties. Quantum Theory : 1900Planck discovers that heat energy is not continuously variable, as chemical physics assumes. There is smallest common coin in the currency, the quantum and all transactions are in multiples of it. Photons: 1905 Einstein realises that light, too, has to be understood not only as waves but as quantum particles, later known as photons The Nucleus:1910 Rutherford shows that the electrons orbit around a tiny nucleus, in which almost the entire mass of the atom is concentrated. FROM THE BEGINNING OF MODERN ATOMIC THEORY TO HIROSHIMA: AN OUTLINE SKETCH OF THE SCIENTIFIC AND HISTORICAL BACKGROUND TO THE PLAY.

18. The Quantum Atom: 1915Bohr realises that quantum theory applies to matter itself. The orbits of the electrons about the nucleus are limited to a number of separate whole number possibilities, so that the atom can exist only in a number of distinct and definite states. (The incomplete so-called “old quantum theory”) • Matter as Waves: 1924 De Broglie in Paris suggests that, just as radiation can be treated as particles, so the particles of matter can be treated as a wave formation. • The Wave Equation: 1925 Schrödinger finds the mathematical equation for the wave interpretation, and proves that wave and matrix mechanics are mathematically equivalent. • Quantum mechanics: 1925Heisenberg abandons electron orbits as unobservable. Max Bohn finds instead a mathematical formulation in terms of matrices for what can be observed – the effects they produce upon the absorption and emission of light.

19. Uncertainty: 1927 Heisenberg demonstrates that all statements about the movement of a particle are governed by the uncertainty relationship: the more accurately you know its position, the less accurately you know its velocity, and vice versa. • The Copenhagen Interpretation: 1928 Bohr relates Heisenberg’s particle theory and Schrödinger’s wave theory by the complementary principle, according to which the behaviour of an electron can be understood completely only by description in both wave and particle form. Uncertainty plus complementary become established as the pillars of the Copenhagen (or “orthodox”) interpretation of quantum mechanics.

20. Neutrons: 1932 Chadwick discovers the neutron – a particle which can be used to explore the nucleus because it carries no electrical charge, and can penetrate it undeflected. • Into the Nucleus: 1932 Heisenberg opens the new era of nuclear physics by using neutrons theory to apply quantum mechanics to the structure of the nucleus.

21. Transmutation: 1934 Fermi in Rome bombards uranium with neutrons and produces a radio-active substance which he cannot identify. The liquid drop: 1937 Bohr explains the properties of the nucleus by analogy with a drop of liquid. Identification: 1939 Hahn and Strassmann in Berlin identify the substance produced by Fermi’s bombardment as barium, which has only about half atomic weight of uranium. Fission: 1939 Lise Meitner and Frisch in Sweden apply Bohr’s liquid drop model to the uranium nucleus, and realise that it has turned into barium under bombardment, by splitting into two, with the release of huge quantities of energy.

22. The Neutrons Multiply: 1939 Bohr and Wheeler at Princeton (US) realise that fission also produces free neutrons. These neutrons are moving too fast to fission other nuclei in U-238, the isotope which makes up 99% of natural uranium, and will fission only the nuclei of the U-235 isotope, which constitutes less than 1% of it. • The Chain Reaction: 1939 Joliot in Paris and Fermi in New York demonstrate the release of two or more free neutrons with each fission, which proves the possibility of a chain reaction in pure U-235.

23. The War: 1939 The Second World War begins and Germany at once commences research into the military possibilities of fission The Critical Mass: 1940 Frisch and Peierls in Birmingham (UK) calculate, wrongly but encouragingly, the minimum amount of U-235 needed to sustain an effective chain reaction. The Manhattan Project:1942 The Allied atomic bomb programme begins. The Reactor: 1942 Fermi in Chicago achieves the first self-sustaining chain reaction, in a prototype reactor. The Bomb: 1945 The bomb is successfully tested in July, and in the following month used on Hiroshima and Nagasaki (Japan). Germany Defeated: 1945 The Allied advance into Germany halts the atomic programmes there.