Quantum-mechanical estimation of rectangular waveguide parameters with atomic entropy computation L. Kumar, V. Shankar Pandey, H. Parthasarathy, V. Shrimali and G. Varshney Eur. Phys. J. Plus, 132 6 (2017) 285 Published online: 29 June 2017 DOI: 10.1140/epjp/i2017-11558-9