kith said:In ordinary quantum mechanics (QM), you treat the quantum mechanically.
In quantum field theory (QFT), you treat fields quantum mechanically. It turns out that in addition to the classically known fields (like the electromagnetic field) there are new "quantum fields" for all fundamental particles (like the electron). In this sense, QFT is more fundamental than ordinary QM. The most fundamental theory up to date -the Standard Model of particle physics- is a QFT.
DrClaude said:I would like to add the important fact that QFT was necessary to allow for particles to be created and annihilated, which isn't in the framework of the original quantum mechanics.
Quantum field theory is a theoretical framework that combines the principles of quantum mechanics and special relativity to explain the behavior of particles and their interactions in the subatomic world.
The main goal of quantum field theory is to provide a mathematical description of the fundamental forces and particles in the universe, and to understand how they interact with each other.
Quantum field theory takes into account the principles of quantum mechanics, such as uncertainty and wave-particle duality, while classical field theory only considers classical mechanics and does not account for the behavior of particles at the subatomic level.
The quantum field is a mathematical concept that describes the behavior of particles and their interactions in the subatomic world. It is represented by a field that permeates all of space and time, and is responsible for the creation and annihilation of particles.
Quantum field theory explains the behavior of particles by treating them as excitations of the underlying quantum field. These excitations can be thought of as waves or vibrations in the field, which interact with each other to produce observable particle phenomena.