The Racah Institute of Physics aspects related to high-Tc superconductivity. On the experimental side, benefiting from the facilities of the Harvey M. Krueger center for nanoscience and nanotechnology, researchers apply modern measuring and fabrication techniques to study the physics of nano-structures, their application to quantum information processing, the interaction of light and matter, high-Tc superconductivity, and the physics of electron glasses. More specifically, and summarizing but a few of the research directions, researchers study excitonic fluids in semiconductor nanostructures with an eye on both a better physical understanding of their macroscopic quantum coherence properties and possible future applications in electro-optic devices. Josephson junctions are being
Action (physics) (see also below). The action is defined by an integral, and the classical equations of motion of a system can be derived by minimizing the value of that integral. This simple principle provides deep insights into physics, and is an important concept in modern theoretical physics. "Action" was defined in several now obsolete ways during the development of the concept. Expressed in mathematical language, using the calculus of variations, the evolution of a physical system (i.e., how the system actually progresses from one state to another) corresponds to a stationary point (usually, a minimum) of the action. Several different definitions