T.K. Raidastidar Memorial Lecture 2018

Speaker  :

Professor Hema Ramachandran
Raman Research Institute, Bangalore

Topic      :

“ Noise, the new signal ”

Date      :

Thursday, 15th March, 2017

Time      :

03:30 PM

Venue    :

C.V. Raman hall, IACS

Abstract    :

Traditionally, noise is defined as unwanted signal. Experimenters world-over take elaborate steps to eliminate noise to the maximum extent possible, from their measurements. However, in recent times, it has emerged that noise can provide valuable information about the system under study. This new role of noise forms the subject matter of my talk. Beginning with a brief overview of various fields that have utilised this concept, I will focus on three distinct experimental studies carried out in our laboratory that have used noise to glean information about the underlying physics of the systems being investigated.
In the first set of experiments, the intensity fluctuations of light emitted by a random amplifying medium were examined, revealing Levy flights of photons, for the first time, in a laboratory experiment. After a discussion of this work, I will proceed to describe the second study that involved intensity-interferometry using light emitted by ultracold atoms. This Hanbury-Brown Twiss type of measurement unveiled hidden periodicities in the absorption-emission processes in a thermal cloud – the Rabi oscillations. Finally, I will proceed to the third set of experiments that involves spin noise spectroscopy in an atomic vapour. This simple experiment enables a precise determination of the atomic parameters – the electronic and nuclear magnetic moments, and the hyperfine splitting.

All are cordially invited to attend