Explore a 28-minute conference talk by Łukasz Rudnicki from the University of Gdańsk on the Reduced State of the Field formalism and Dynamical Casimir Effect. Delivered during the Symposium celebrating Professor Iwo Birula-Białynicki's 90th birthday, this presentation delves into advanced concepts in theoretical physics. Gain insights into cutting-edge research in quantum field theory and its applications. The talk was part of a special event held at the Faculty of Physics, University of Warsaw, featuring notable speakers including Nobel laureate Prof. Anton Zeilinger, and included the presentation of the Wigner Medal and a special issue of Acta Physica Polonica A.