by Elena Castellani | 24 August 2020

Paola Verrucchi was born in Florence and got her PhD in theoretical condensed-matter physics in 1994 at the Physics Department of the University of Florence, with a thesis in collaboration with the Institut fur Theoretische Physics of the University of Hannover. Between 1994 and 1997 she worked as a Post-Doc at the research project  "Theoretical  Condensed Matter Physics: a work in support of Neutron Spectroscopy" at the ISIS Theory Division of Rutherford Appleton Laboratory in Oxford. Back in Italy, she worked at the University of Florence, the Italian Institute for Physics of Matter (INFM), the Italian Institute for  Nuclear Physics (INFN) and the Italian Research Council (CNR). Since 2008 she is a permanent Researcher at the Institute for Complex Systems (CNR) in Florence and she regularly teaches at the University of Florence (a PhD course in Physics and a MS course in the MA Program in Logic, Philosophy and History of Science).

The recent activity of her research group is devoted to the study of open quantum systems and their dynamics. In particular, the group works on different possibilities for controlling quantum devices specifically designed for accomplishing quantum-information and quantum-communication tasks. Decoherence, non-markovianity of open quantum systems dynamics, as well as fundamental issues about the quantum measurement process and the nature of time, are some of the topics currently under investigation.

When and why did you decide to work on Quantum Mechanics?

In my third year at the university I fell in love with Quantum Mechanics (QM), without understanding why, really. Later on I realized that QM had liberated me from the nightmare of having to visualize problems in order to solve them. In fact, I have never been able to guess how a weight should move along an inclined plane, or in a pulley system, and I started enjoying my studies only when I met analytical mechanics, which is the most abstract formalization of classical physics. When QM taught me that there is no need of visualizing anything and that whatever we experience is just an extremely poor version of a much richer universe around us, it was love at first sight. Since then, QM has always been the language I use to study, work, and probably think.

What is it that especially fascinates you in QM?

I believe that each of the four postulates (and I am here referring to the most essential formulation of the theory) is an extraordinary breakthrough: 1) systems are in superpositions of distinguishable states, and 2) they evolve so as to mantain full consistency with the results of measurements. On the other hand, 3) the results of measurements embody all the information available to us, and 4) this information is conveyed via the generation of entanglement, which means that during the measurement process the observer and the observed object are one single, highly correlated, system. I think this is amazing! Another aspect that I truly love in QM is that it allows different interpretations to be chosen. In fact, despite having been considered a weakness of the theory for decades, this is one of its greatest merit, in my opinion, as it means that while being a rigorous theory, QM does not require a dogmatic adhesion to a specific description of what lies behind the experimental results. In a sense, QM is a humble theory: it provides us with a minimal set of general laws, and then leaves anyone free to elaborate on their interpretation. Let me also mention that the way QM makes it clear that what we humans experience is just a tiny fraction of the available physical world, in terms of energy, time, space…, is thrilling.

Why do you think that QM enters everyday life and society?

There are two complementary aspects in this regard. On the one hand, scientific theories bring innovation and progress on the practical side of our everyday life, thanks to new and powerful applications. This is where QM has constantly declared its power since the late '30s of the last century: from nuclear energy to transistors, from lasers to nuclear-magnetic-resonance, up to nowadays quantum computers and quantum networks. On the other hand, though, there is a more subtle aspect, which is the way any gained knowledge about the laws ruling the world around us change our notion of concepts such as observation, interaction, correlation, time, evolution…, that actually shape our way of thinking. This second aspect, though, develops only when the theory is made available also to non-experts, at least in its basic elements. From this viewpoint QM is plodding along, and ever too often (and erroneously) considered too difficult for being taught to young students or narrated to the public.

Which one of these two aspects do you think is more relevant?

They are equally important and there should be a balance in the way they progress. In fact, as the second aspect is evidently behind, I think that at the moment there should be a strong effort to favour a serious and rigorous popularization of QM, to allow the theory to be metabolized by the entire society.

What is the role of philosophers in this process?

Philosophers play the essential part of continuously question the mathematically dogmatic or experimentally irreplaceable statements of the physicists. In this way, they transform the fundamental statements of scientific theories from “cold” postulates to articulate interpretations, and transfer the specialized expertise of physicists to the vast framework of general culture.

How do you relate with philosophy students and colleagues?

Dealing with philosophy students and professors has become an essential element of my work as a researcher in physics: not only our discussions challenge me to understand what are the fundamental consequences of whatever I might teach as if it were just a postulate of an abstract theory, but each question that a student ask, most often so different from those asked by physics students, lights me up with curiosity towards foundational aspects that I utterly ignored and interpretations of our universe that are new to me. This dialogue makes my research so much deeper, and more fun, that today I can hardly imagine to do without it.