A 22-year-old student predicted in 1962 the mathematical relationships for the current and voltage across a weak link coupling two or more superconductors. Since then, the world of superconductivity has never looked back. That monumental achievement in the Cavendish laboratory not only made Brian Josephson the only Welshman in history to win the Nobel Prize in Physics (in 1973) but also made him a luminary in the field of condensed matter physics.
Unassuming, simple and as brilliant as always, Brian Josephson remains one of the last among the Cavendish giants in condensed matter physics after the likes of Sir Nevill Francis Mott and Philip Warren Anderson. In this interview, I, his postdoctoral research-student who is working on emergent symmetries in Physics, interview him on Physics, the Josephson Effect, the recent Mind-Matter Unification Project and his work at the intersection of a number of fields, some of which have been the centre of mixed reactions, in the Cavendish Laboratory.
Mrittunjoy Guha Majumdar (MGM): How was your experience learning Physics, as a student and researcher, and then teaching at Cavendish Laboratory over the years?
Brian D. Josephson (BDJ): I had a very helpful physics teacher at school. He lent me the book Theoretical Physics by Joos to read and I was surprised to learn that you could actually calculate properties of matter (using quantum theory) rather than just measuring them. As an undergraduate, I switched from part II Maths to part II Physics for my 3rd year, as what was studied in applied maths at that time had little to do with the real world. For my PhD project, I decided to do an experiment (on ‘nonlinearity in superconductors at 178 MHz’), as the idea of sitting a desk all day did not appeal to me, though of course, that is what I ended up doing later when I switched to theory.
MGM: We would love to know about your discovery of the Josephson Effect and how that came about.
BDJ: I was the only person in the low-temperature group who could understand the theory of superconductivity, so I needed to become an expert in it so as to be able to offer advice. I learned of the existence of a kind of a wave in a superconductor through studying papers on the subject, and started to wonder if this was something real, as well as just a quantity in the theory. I realised after a bit that while the phase itself was unphysical, in a system with two superconductors phase differences between the two systems could have consequences if electrons could move from one to the other. Then Ivar Giaever came out with his junctions that fitted the requirements, and later a paper was published by Cohen et al. that calculated the behaviour of the junctions and justified Giaevar’s calculation. Fortunately for me they could not figure out what the phases meant so did not deal with the two-superconductor case and so I did the calculation for that case and was surprised to discover the zero-voltage contribution which I was not expecting.
Incidentally, while I was an undergraduate I learnt about the Mössbauer effect and realised that relativity implied that the frequency should be a function of temperature. This had a significant influence on an experiment being carried out at Harwell, and rather baffled the researches who couldn’t figure out what was happening. I wrote to them and in response, they sent a uniformed driver to take me there so as to write the idea up for publication, which much impressed a friend who saw me being collected.
MGM: Interdisciplinarity has become a major point of interest for groups such as Theoretical Condensed Matter Physics in the Cavendish today. One has research bridging fields as disparate as cosmological phenomena and condensed matter physics and, more generally and popularly, areas of biology and physics. What are your thoughts on the same?
BDJ: I think interdisciplinarity is important, but it tends to have more problems getting support than does work in a single discipline.
MGM: Recently you have started looking at the Physics of the Mind as part of the Mind-Matter Unification Project. Please tell us a little about that.
BDJ: There seems to be a ’two cultures’ situation, in that physicists don’t know much about meaning while people working on the role of meaning don’t treat it in the way physicists do. So there should be mileage in bringing the two approaches together to make a unified theory. A preprint I’ve posted on ResearchGate has attracted considerable interest — in fact on occasion it is the most read paper of all of those published by people in the physics department.
MGM: You mention coordination dynamics and the idea of synergy in systems. How do you think that can help us understand the intricacies of intelligent processes in the physical world?
One of my interests in that connection is the phenomenon of language, where there are computer models that treat it very effectively in terms of a collection of units that work together. This in a way explains how some aspects of intelligence work, and the challenge is to treat this in a systematic fashion so as to understand it more clearly.
MGM: We have recently started looking at emergent symmetries and the fundamental forces of nature. This ties into the idea of looking for ways to create order and symmetry out of instability. What are your thoughts on the same?
BDJ: The point is basically that systems tend to settle down into symmetrical forms, something that can have mathematical expression. That is one of these facts that are ’true for no reason’ or, as the philosopher Merleau-Ponty put it, ’that is the way things are, and nobody can do anything about it’.
MGM: You have always been a good science communicator, having spoken on a number of areas within Physics and beyond too. How important do you think it is to be a good science communicator to be an effective scientist today?
BDJ: Thank you for that comment. In this day and age, it is being able to communicate in great detail to funding organisations that matters, so as to be able to get the funding needed to do research. And you have to be able to say what your research will achieve before you have done it! It’s a crazy situation, just like the recent ruling of the department that emeritus staff such as myself will have to justify having access to the department, every six months in some cases (though there are suspicions that they actually mean every two years, but being scientists they got biannual and biennial mixed up in the text).
This interview was originally taken for BlueSci – Science Magazine of Cambridge University by me, in my capacity as secretary of BlueSci.