What are Quantum fields?

Question

I’ve read that QFT states that all the interactions in the quantum mechanics take place along the Quantum fields. What are these fields?

Answer 1

In relativistic quantum field theory, quantum fields are operator-valued distributions. As shown, for example, by Weinberg, fields inevitably arise as a low-energy effective description of quantum mechanical interactions constrained by special relativity (in particular that the dynamics are invariant under Poincaire transformations), unitarity, and the cluster decomposition principle (which essentially encodes the idea that interactions should be local). In other words, regardless of the true fundamental high energy / short distance degrees of freedom (whether they are strings or something else), at sufficiently low energies, we can use quantum field theory to describe relativistic quantum systems.