No, it is not accurate to say that an individual photon doesn't have a single amplitude. In quantum mechanics, the amplitude associated with a photon is typically described by its wave function or, more precisely, the probability amplitude associated with finding the photon at a particular location.
Each individual photon can be described by a wave function that characterizes its probability distribution in space. This wave function contains information about the photon's amplitude and phase at each point in space. However, unlike classical waves, the wave function of a single photon does not represent a physical wave in physical space but rather a mathematical description of the photon's quantum state.
When multiple photons are present, the total wave function of the system is determined by considering the combined states of all the photons. In this case, constructive or destructive interference can occur between the individual photon wave functions, leading to an enhanced or diminished probability amplitude at specific locations. The interference patterns emerge from the probabilistic nature of quantum mechanics.
It's important to note that the concept of interference in quantum mechanics is probabilistic. It does not mean that the individual photons themselves are physically interfering with each other. Instead, it refers to the probability amplitudes associated with the possible outcomes of detecting the photons.
So, while it is true that constructive interference can lead to an increase in the average amplitude when multiple photons are considered, it is not accurate to say that individual photons lack a single amplitude. Each photon has its own associated probability amplitude, and interference occurs when considering the collective behavior of multiple photons.