Obituary: Professor David Bohm

David Joseph Bohm, physicist, born Wilkes-Barre Pennsylvania 20 December 1917, Assistant Professor Princeton University 1947-51, Professor University de Sao Paulo 1951- 55, Technion Haifa 1955-57, Research Fellow Bristol University 1957-61, Professor of Theoretical Physics Birkbeck College London University 1961-83 (Emeritus), FRS 1990, married 1956 Sarah Woolfson, died London 27 October 1992.

DAVID BOHM was a leading figure in the world of quantum physics and Professor of Theoretical Physics at Birkbeck College, London University, from 1961 to 1983.

David Bohm was born in Wilkes-Barre, Pennsylvania, in 1917. He graduated from Pennsylvania State College in 1939 and then successfully completed his Ph D thesis at Berkeley under the guidance of Robert Oppenheimer. This early work was concerned with neutron-proton scattering and the theoretical design aspects of early particle accelerators. He moved on to the Radiation Laboratory where he worked on the Manhattan Project. It was here that he developed important new theoretical techniques to describe oscillations in plasmas and it was this work that established his reputation as a theoretical physicist.

In 1947 Bohm moved to Princeton University. Here he applied his earlier ideas on plasmas to study the behaviour of electrons in metals. His innovative flair enabled him to make outstanding contributions to the fundamental understanding of electrons in metals. The work with his graduate student David Pines is still internationally recognised as playing a fundamental role in the development of this field.

It was at Princeton that Bohm's intense interest in the foundations of quantum mechanics took root. In order to obtain a better understanding of the subject he decided to write a textbook on the subject, Quantum Theory (1951). It was widely acclaimed as one of the best presentations of that era and is now regarded as a classic. Even Einstein remarked that it was probably the clearest exposition that could be made for the usual interpretation. But after he had completed it, Bohm said that he became convinced that the interpretation was not entirely satisfactory. Indeed, immediately after completing the book, he published two papers showing that an alternative approach was possible and that this approach seemed to do what the orthodox view deemed to be impossible.

It was at this stage that Bohm became embroiled in McCarthyism. For reasons that I have never been able to unravel to my satisfaction, he was called to appear before the Un-American Activities Committee to testify against colleagues. Being a man who believed passionately in the freedom of debate, he decided to plead the Fifth Amendment. Unfortunately this was taken as an admission of guilt and he was from then on classified as a 'Marxist'. This to me is a travesty of the truth and in my 30 years working with him I never heard him even mildly defending such a faith. Nevertheless, as a result of this episode, his contract at Princeton was not renewed and Oppenheimer advised him to leave the country. He secured a teaching post in Sao Paulo, in Brazil, then spent a year at the Technion in Israel, before taking a fellowship at Bristol University, in 1957.

At Bristol Bohm was joined by a graduate student, Yakir Aharanov. Together they published an important paper pointing out that surprising observational consequences of the vector potential. At first their idea was not well received, but it was soon experimentally confirmed. Recently, John Maddox, the editor of Nature, has suggested that this work was a possible candidate for the Nobel Prize. In his typically modest way, David told me that he did not regard this work as 'that important'.

In 1961 Bohm took the chair in Theoretical Physics at Birkbeck College, retiring in 1983. It was during this time that I worked with him as colleague and co-researcher. For me and for our students the daily contacts with David were the most intellectually stimulating and enjoyable years of our lives. During this time he was trying to develop radically new ways of looking at quantum phenomena. Bohm's view, based on determinism and causality, raised doubts that the quantum formalism necessarily implies indeterminism and acausality and his view is now thankfully getting more careful consideration. What the Danish physicist Niels Bohr called 'wholeness' also appears in Bohm's view as 'nonlocality'. It is these features that led Bohm to search for new categories; as he would put it, new 'orders' are needed to account for quantum phenomena.

The search for new concepts led us to look also into language structure, the nature of thought, the mind-matter question and, ultimately, into the nature of consciousness. Bohm brought a new perspective and clarity to whatever he touched. His later books, Wholeness and the Implicate Order (1980) and Science Order and Creativity (1987, co-authored with David Peat), give a partial insight into the radical philosophies he was investigating.

Although Bohm's ideas have reached and inspired a worldwide audience, formal recognition of his outstanding achievements in physics were very late in coming. He was elected a fellow of the Royal Society in 1990 and was awarded the Franklin Institute's Elliott Cresson medal in 1991. Although courageous and tenacious in defending his ideas, his natural humility and gentleness were such that he did not actively seek honours, and it was this quality that people so admired.

Although he officially retired from Birkbeck in 1983, for David retirement involved spending more time than ever at the college discussing his latest thoughts. Indeed he was there the day he died, talking over his recent proposals and putting some finishing touches to his latest book, The Undivided Universe.