CREF research activity is not thematic in nature and therefore intends to focus on complementary activities compared to other national scientific institutions: activities that are particularly current, innovative and have an interdisciplinary character, placing themselves in the area that is today known as “complex systems”. In particular, CREF aims to be a sort of incubator for scientific start-ups.
The area of physics called complex systems is complementary to the traditional one of elementary particle physics. The traditional approach to physics, in fact, is to consider the simplest systems and study them in detail: this reductionist vision can be applied to many situations and necessarily implies the existence of characteristic scales such as the size of an atom, of a molecule or some macroscopic object. The basic philosophy is that from the knowledge of the ultimate elements of matter, one can understand the behaviors of systems made up of many bodies. On the other hand, many situations are known in which knowledge of the individual elements is not sufficient to characterize the properties of the entire system. In fact, when many elements interact in a non-linear way, they can lead to the formation of complex structures whose properties are not simply related to, or deducible from, the properties of the individual elements that constitute them. In these cases we can think of a sort of architecture of nature, which certainly depends on the elementary constituents but which, moreover, manifests fundamental properties and laws that cannot be simply deduced from those of the elementary constituents. This point of view was brought into focus in a famous article by P.W. Anderson (PWA), Nobel laureate in physics in 1977, who had a strong impact on developing complex ideas.
Phil Anderson summarized this conceptual revolution in his 1972 article entitled “More is different”: The more is different. The basic idea is as follows: in physics the traditional approach considers the systems simpler and studies them in detail; this reductionist approach focuses on the elementary “bricks” that make up matter and is successfully applied to many phenomena. From this it was possible to derive the general laws that extend from the scale of the atomic nucleus to that of the galaxies. It is easy, however, to realize that as soon as the degree of complexity of the structures and systems increases, and when these are composed of many elements interacting with each other, we are faced with new situations, in which the knowledge of the properties of the elements individual (e.g. particles, atoms, planets, stars, etc.) is no longer sufficient to describe the overall system as a whole. The point is that when they interact with each other, these elements form complex structures and develop collective behaviors that have little to do with the properties of the individual isolated elements: the individual elements have a relatively simple behavior, but their interactions lead to new phenomena emerging. For this reason, the overall behavior is fundamentally different from any of its elementary sub-parts. In this sense we can represent this situation as the study of the “architecture” of matter and nature, which depends in some way on the properties of the “bricks”, but which then shows fundamental characteristics and laws that cannot be linked to those of the individual elements.
According to Anderson, reality therefore has a hierarchical structure and at each level of the hierarchy it is necessary to introduce concepts and ideas different from those used in the previous level. In simple words: from the knowledge of the fundamental laws that regulate the interaction between elementary particles it is not possible to understand the formation of many of the phases of condensed matter and, even more so, of increasingly complex systems, up to the biological systems and social aggregates. This situation leads to an interesting epistemological consideration: while reductionist physics is usually deductive, understanding a phenomenon of collective organization very rarely occurs through deduction. The deductive logical procedure therefore shows its fundamental limitation when applied to complex phenomena. While many complex systems have been studied in the field of physics, in recent years there have been many attempts to apply this reasoning also to systems that can appear very far from physics such as socio-economic disciplines.