Activities

S N Bose, Bose-Einstein Condensation,
and Its Relation to Current Information Technology

BY

Prasanta Kumar Basu
Retired Professor, Institute of Radio Physics and Electronics,
University of Calcutta

Abstract: Satyendra Nath Bose, with Einstein’s help, published two papers in Zeitschrift fur Fysik in 1924. His theory could explain Planck’s radiation law without any ad hoc assumptions. Thus came Bosons, with photons as a member, as a quantum particle. Einstein used Bose’s statistics to propose a new phase, leading to Bose Einstein Condensation (BEC), in which all bosons having integer spin, condense into the lowest lying phase coherent state. The idea was experimentally verified during 1990’s with Rd+ and Na+ atoms cooled to micro Kelvin temperature. For their work, Cornell, Weiman and Ketterle got Nobel Prize in Physics in 2001.

Excitons in semiconductors are electron-hole pairs bound by Coulomb interaction as in a H atom and have bosonic character. Since 1960’s, they were considered as a suitable candidate to observe BEC at room temperature and above. The search intensifies after 2000. Finally BEC is observed in a semiconductor microcavity structure in 2006. The highly coherent state made of excitons gives a coherent emission of photons like lasers, requiring less input power. The laser, called the polariton laser, operates at room temperature with electrical input and is expected to play a role in current and future information technology.

The webinar aims mainly to give historical sketches, and to explain the technical terms in simple language to persons even with knowledge in higher secondary physics.

* Open to all and no registration is required.