1. Department of Mathematics, Aliah University, Sector - V, Salt Lake, Kolkata 700091, India
2. Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal, India
3. Department of Physics, Purulia Zilla School, Purulia, West Bengal, India
4. Department of Physics, Aliah University, Sector - V, Salt Lake, Kolkata 700091, India
5. Department of Physics, Government College of Engineering and Ceramic Technology, Kolkata 700010, West Bengal, India