У оквиру сеимнара Групе за гравитацију, честице и поља, у петак, 22. маја 2026. године у 11 часова у сали 360 Института за физику у Београду, Никола Паунковић (Институт за физику у Београду) одржаће предавање:
Quantum information geometry and applications to phase transitions of many-body systems
САЖЕТАК:
As a follow-up to my previous seminar in which I introduced myself to colleagues from the Institute and Belgrade, I will present a brief technical overview of information geometry of quantum states and its application to the study of phase transitions in many-body systems, with a special focus on the results I was involved in during the past 20 years of research. On the example of classical physics and probability
distributions, I will first briefly introduce how the notions of information and geometry fit in the description of this line of research. Then, I will analyse in more detail three particular geometries of quantum states: a pure-state U(1) Berry gauge geometry, and two distinct mixed state geometries, one equipped with U(N) gauge group (Uhlmann), as well as the so-called interferometric geometry obtained from a symmetry broken Uhlmann gauge group [U(N) –> \otimes_i U(N_i), with \sum_i N_i = N]. I will then move to describe the so-called fidelity approach to the study of phase transitions. Being based on an abstract notion of state distinguishability (the notion that gives rise to information geometry), it is intended to present a general approach to the study of phase transitions that goes beyond Landau Ginzburg and other partial approaches. I will introduce the so-called fidelity susceptibility (a metric field over the space of states) and discuss it on a few examples of many-body systems, showing its explicit connection to dynamical susceptibilities of both zero-temperature quantum and finite-temperature equilibrium phase transitions. If time permits, I will also briefly discuss recently introduced non equilibrium dynamical phase transitions and their connection to the geometry of channels and processes.