1. Department of Physics, National Defence Academy, Khadakwasla, Pune, Maharashtra 411023, India
2. Department of Physics, Malda College, Malda 732101, West Bengal, India
3. Department of Mathematics, Government General Degree College, Singur, Hooghly, West Bengal 712409, India
4. Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal, India