Satyendra Nath Bose

Satyendra Nath Bose (1894-1974), Indian mathematician and theoretical physicist, known for his contributions to the field of statistical mechanics, in collaboration with Albert Einstein.

Bose graduated in applied mathematics from the University of Calcutta. He published a number of papers in fields as diverse as crystallography and unified field theory while lecturing at the universities of Dacca and Calcutta. His paper, “Planck's Law and the Hypothesis of Light Quanta”, published in 1924, in which he derived Planck's equation purely from quantum theory, using his model for the behaviour of a group of photons, was sent to Einstein. Highly impressed, Einstein entered into a collaboration with Bose, and further extended Bose's work on the behaviour of photons, which are particles of zero spin, resulting in what is now known as Bose-Einstein statistics. This behaviour, characterized by the ability of any number of particles to occupy the same energy state (degeneracy), applies to any group of particles of integral spin, or bosons, as they are now called. This is in marked contrast to the behaviour of fermions, or particles with nonintegral spin, such as electrons (spin 1/2), which are subject to the Pauli Exclusion Principle, preventing any two particles occupying the same quantum state. At low temperatures, a large number of bosons may occupy the same energy state, resulting in what is known as a Bose condensation.

The impact of Bose-Einstein statistics has proved to be wide-ranging, explaining, for example, the action of lasers and the superfluidity of helium at low temperatures (the helium nucleus also has integral spin). Bose became professor of physics at the University of Calcutta in 1945 and vice chancellor of Vishwabharati University in 1958.