Seminarium Fizyki Materii Skondensowanej

In physics, chemistry and biology it is often observed that the curves of a physical quantity f(x,p) cross at one or more points, when plotted as a function of x for different values of some parameter p. Sometimes these crossing points are confined to a remarkably narrow region, or are even located at a single point called "isosbestic point". For example, isosbestic points are found in the curves of the specific heat of many correlated electron systems, as well as in their photoemission spectrum, reflectivity, and Raman response. I will show that isosbestic points always provide valuable information about the system in which they occur.