Description:

Title: Quantum Mechanics and Electron Bubbles in Liquid Helium

Speaker: Humphrey Maris, Brown University

Abstract: In quantum mechanics the state of a system is described by the wave function. It is remarkable that according to the theory the wave function changes with time in two seemingly distinct ways. There is a change in time which can be calculated from the time-dependent Schrodinger equation, and also the wave function is believed to change discontinuously as a result of measurements. However, despite much effort what constitutes a measurement and how a measurement can cause a change in the wave function remains uncertain.

I will describe a  series of experiments with electrons in superfluid helium which may shed some light on these questions. An electron entering liquid helium forces open a cavity referred to as an electron bubble.  Experiments have revealed that in addition to these normal electron bubbles there are other negatively charged objects in liquid helium. Despite much effort the structure of these so-called “exotic ions” remains unknown. We will discuss the possibility that these objects are bubbles in the liquid which each contain only a fraction of the electron wave function.

Host: William Halperin

Speaker Schedule

Keywords: Physics, Astronomy, colloquium