Speaker
Dieter Vollhardt
(U Augsburg)
Description
In physics and chemistry 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 the 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, crossing points are found in the curves of the heat capacity C(T,X) of many correlated materials, with X as the pressure or the magnetic field, and of the Hubbard model, with X as the interaction U, but also in the Raman response chi''(omega,T) and many other quantities. I will explain that crossing points provide valuable information about the system in which they occur.
