Research
My research activity began with intense, obsessive personal commitment, above all seeking to contribute something new, to add a small booklet – as Cajal put it – to the vast library of knowledge, rather than carrying all of that library in my head. The philosopher Whitehead rightly remarked that the researcher seeks to know in order to discover, rather than discovering in order to know, which is more the province of the learned scholar. Anyone who has experienced the pleasure of seeing something for the first time, no matter how small, the “moment of discovery”, will be hooked forever and find it difficult to give up research.
My speciality is theoretical condensed matter physics. A high degree of creativity is required to find a way – conceptually, mathematically and experimentally – to focus on the essentials, to obtain precise information that allows us to understand mechanisms: the emergence of new properties, reducible, but not deducible from those of the constituents. The whole is not merely the sum of its parts; it is qualitatively different. Generally speaking, condensed matter physics only proves approximate theorems. In this apparent modesty lies its complexity and greatness. It is – like all science – the art of scientific imagination, the art of approximation.
After completing my postdoctoral studies, I broadened my activity to include research supervision, overseeing numerous doctoral theses.
I have enjoyed collaborating on projects with high-impact results – as people say now – in electron dynamics in solids and at surfaces, electron-electron and electron-phonon interactions, the discovery of a new class of quasiparticle and its properties, acoustic surface plasmons, attosecond physics, both in core-holes and in the first experiment explaining “how they run” as “how they dance”, as well as in the existence and dynamics of electrons in topological states.
Close collaboration with cutting-edge experimental groups has shed light on the cause of the short lifetimes of Shockley-type surface electronic states, led to a proposed new method of estimating the levels of charge transfer between an adsorbed atom and a metallic surface based on soft X-ray spectroscopy, the development of atomic-scale real-time control of electron transport in solids, an understanding of the effects of angular enhancement on such transport, and recent research on new materials that are bulk insulators but surface conductors.
Throughout my life, the importance I attach to scientific communication has grown. As scientists, we have an obligation to be responsible citizens, to explain to society what we do, why we do what we do and what purpose it serves. To explain, in a rational manner, the many positive aspects of science, without hiding the negative aspects of some of its applications. We must raise our voices whenever intolerance and irrationality are espoused. We owe it to our profession because, as the great Harvard historian Gerald Holton reminds us, science stands not only on the shoulders of past giants, but also on the graves of many who have fought and suffered to defend rationality and critical thinking.
Today, the exponential development of scientific research makes being a renaissance man virtually impossible. We must aspire and build renaissance teams. I believe in teamwork, while remembering that an idea always originates in the mind of one person. Throughout my life I have had the good fortune to collaborate with many extraordinary people. I feel extremely lucky. I would like to express my heartfelt gratitude to all of them for what we have built together.
