Physics

Prof. Sushanta Dattagupta
Bose Institute, Kolkata

Abstract: 

We will discuss how a combination of electrodynamics and quantum mechanics makes possible interference measurements of the quantum phase in terms of the vector potential neither of which is detectable independently. This effect, predicted by Aharonov and Bohm (AB-effect) about sixty years ago, is of great significance in the contemporary interesting topic of nanoscopic physics. We will also indicate how the AB-effect can be incorporated in a solid state device by employing the tight-binding (TB) model. The TB model can be realized in a mesoscopic ring which allows for measurement of a bond current and the associated diamagnetism. An exactly solvable case of a three site ring will be presented that serves as a pedagogical example providing further insights into the phenomenon. For futuristic purposes we will also touch upon the issue of noise that can lead to decoherence in an otherwise quantum coherent AB-phenomenon.