Research Article

1Theoretical Physics Section, Bhabha Atomic Research Centre, Mumbai 400085, India

2Department of Physics, Indian Institute of Technology, Mumbai 400 076, India

Received 19 January 2012; Accepted 22 February 2012

Academic Editor: Alejandro Jenkins

Copyright © 2012 G. Gangopadhyay and P. Patra. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.