The concept of virtual particles in quantum field theory is a mathematical tool used to describe and calculate interactions between elementary particles. Virtual particles are not directly observable or detectable like particles in the usual sense. Instead, they arise from fluctuations in quantum fields and exist only within the framework of quantum field theory.
In this sense, virtual particles are not considered "real" in the same way as observable particles, such as electrons or photons. They do not persist as independent entities with definite properties like mass or charge, nor can they be directly measured or detected.
On the other hand, potential energy is a concept from classical physics that refers to the stored energy in a system due to its configuration or position. Potential energy, such as gravitational potential energy or elastic potential energy, is associated with real physical interactions and can be observed indirectly through its effects on the system.
So, while virtual particles are a useful mathematical construct in quantum field theory, they are not considered "real" in the same sense as potential energy in classical physics. Virtual particles are a mathematical tool used to calculate interactions and make predictions within the framework of quantum field theory, but they do not have the same ontological status as observable particles or real physical quantities.