The nature of matter and its relationship to energy is a complex topic in physics. According to our current understanding, matter is not merely a phase transition of quantum field energy, but rather it emerges from the interactions of fundamental particles and fields.
In the framework of quantum field theory, particles are viewed as excitations of underlying fields that permeate space. These fields are described by quantum fields that obey specific equations, such as the Dirac field for fermions (particles like electrons) or the Higgs field for giving mass to particles. The interactions between these fields and the exchange of particles, such as photons or gauge bosons, give rise to the diverse phenomena we observe in the physical world.
Phase transitions, on the other hand, typically occur when a physical system undergoes a change in its macroscopic properties due to a variation in external conditions, such as temperature or pressure. These transitions involve changes in the arrangement of particles or the breaking of symmetries, leading to different states of matter.
While there can be connections and interplay between quantum fields, energy, and phase transitions, it would be an oversimplification to state that matter is solely a phase transition of quantum field energy. Matter is the manifestation of the behavior and interactions of particles and fields at the quantum level, and its properties are determined by a combination of fundamental forces, particle properties, and quantum field dynamics.