Exchange interaction independently by physicists Werner Heisenberg and Paul Dirac in 1926. The exchange interaction is sometimes called the "exchange force". However, it is not a true force and should not be confused with the exchange forces produced by the exchange of force carriers, such as the electromagnetic force produced between two electrons by the exchange of a photon, or the strong force between two quarks produced by the exchange of a gluon. Although sometimes erroneously described as a force, the exchange interaction is a purely quantum mechanical "effect" unlike other forces. Quantum mechanical particles are classified as bosons or fermions. The
Palash Baran Pal neutrino physics, Pal has done important work related to grand unification theory and statistical field theory (popularly called thermal field theory). Some of his works deal with the quantum field theoretic calculations of self-energies of photon and neutrino in a background of charged particles (as electrons, positrons or charged weak gauge bosons) in thermal equilibrium. Pal has also ventured into calculations where the background for various elementary particle processes includes a thermal bath of charged particles in presence of constant magnetic field. Palash Pal is also well known for his teaching and has taught various topics of modern physics in