Virtual photons are a fundamental concept in particle physics and quantum field theory that play a crucial role in describing the interactions between electrically charged particles.

…borrowed photons are called “virtual” photons to distinguish them from real photons, which constitute electromagnetic radiation and can, in principle, exist forever. This concept of virtual particles in processes that fulfill the conditions of the uncertainty principle applies to the exchange of other gauge bosons as well.

A major difference between real and virtual photons is that virtual particles are not required to have energy and momentum on the "mass shell". That is, virtual photons may have $E^2-p^2 \neq m^2$, while real photons must obey $E^2-p^2=m^2=0$.

A virtual particle is a theoretical transient particle that exhibits some of the characteristics of an ordinary particle, while having its existence limited by the uncertainty principle, which allows the virtual particles to spontaneously emerge from vacuum at short time and space ranges. [1]

The exchanged particles between the vertices are virtual. They have all the quantum numbers of their name, except the mass which is off mass shell. The photon is characterized by spin=1 and charge=0. The m=0 is not an attribute of a virtual photon.

2011年10月10日 · One says “the electron emits and reabsorbs a virtual photon”, but this is just shorthand for the physics shown in Fig. 3. The language physicists use in describing this is the following: “The electron can turn into a virtual photon and a virtual electron, which then turn back into a real electron.”

A virtual photon is a theoretical concept in particle physics. Virtual photons are thought to be particles that exist for an incredibly brief time and cannot be directly observed. Their existence is inferred through their role in mediating interactions between other particles.

A particle forced into having an apparent mass different from its actual mass is called a virtual particle. The interaction shown in Figure \(\PageIndex{5}\): can only take place if particles A and B come closer to each other than the distance ΔI.

acceleration radiation of a two-level atom, the atom is promoted from |bl to |al by emitting a virtual photon, which becomes real when the atom accelerates away. A change in the center-of-mass motion energy allows energy to be conserved.

These photons are “ virtual”; that is, they cannot be seen or detected in any way because their existence violates the conservation of energy and momentum. The photon exchange is merely the “force” of the interaction, because interacting particles change their speed and direction of travel as they release or absorb the energy of a photon.