The wave-particle duality of light, as demonstrated by experiments such as the double-slit experiment, does provide evidence for the existence of quantum fields. In the context of quantum field theory, light is described as a manifestation of a quantum field called the electromagnetic field.
In quantum field theory, particles are viewed as excitations or quanta of their respective underlying quantum fields. The electromagnetic field permeates all of space, and when it interacts with charged particles, it can exhibit both wave-like and particle-like behavior.
The double-slit experiment, which involves sending light through two closely spaced slits, demonstrates the wave-like nature of light as it produces an interference pattern on a screen behind the slits. This behavior indicates the superposition and interference of different states of the electromagnetic field.
On the other hand, the photoelectric effect and other experiments demonstrate the particle-like behavior of light. In the photoelectric effect, light can eject electrons from a material in discrete packets of energy known as photons.
The fact that light exhibits both wave-like and particle-like properties suggests that the underlying reality is described by a quantum field, where the particle-like behavior arises from the quantization of the field into discrete quanta (photons), and the wave-like behavior arises from the superposition and interference of these quanta.
Quantum field theory provides a framework that extends this understanding to other particles and fields, describing them as excitations of their respective quantum fields. So, while the wave-particle duality of light alone does not directly prove the reality of quantum fields, it does support the broader theoretical framework of quantum field theory, which has successfully described and predicted various phenomena in particle physics.