|
Themes > Science > Physics > Elementary particle physics > Elementary particle physics Today > Quantum Field Theory > Why Second Quantization? |
Our description of the physical world is dynamic in nature and undergoes frequent changes. In this changing picture, the laws of classicalmechanics formulated by Galileo, Newton, and later by Euler, Lagrange, Hamilton, Jacobi and others remained unaltered for almost three centuries. The classical mechanics met its first obstacles around the beginning of this century. The obstruction came on two fronts: at large velocities and small scales. The problem of large velocities was solved by Einstein who gave us relativistic mechanics. The problem of small scale was solved by Bohr, Heisenberg, Schrodinger, Dirac, Born and others. The union of relativity and quantum mechanics needed for the description of phenomena involving simultaneously large velocities and small scales were given by Klein Gordan and Dirac which respectively provided relativistic generalization of Schrodinger equation for particles without and with spin. These one-particle equations led to the possibility of pair production in an infinite sea of sleeping particles which appeared as negative-energy solutions. The quantum field theory then emerged as a new theory in which particles like electron and positron in addition to photons can be created and destroyed. |
|
|