Question

What is difference between first and second quantization?

Answer 1

Answer:

If there is a second quantization, presumably there is also a first quantization. The latter term refers to the ordinary application of the ► Schrödinger equation to physical objects characterized by ► wave functions, while the surrounding environment (such as an electromagnetic field) is treated classically. In second quantization the environment is treated quantum-mechanically — the field is quantized — and the wave function is considered as a dynamical system subject to quantization. To put it differently, one takes the wave function of an already quantized system and turns it into an ► operator.