Virtual particles in quantum physics arise from the mathematical framework of quantum field theory (QFT) and are a consequence of the Heisenberg uncertainty principle.
In quantum physics, particles are described as excitations of quantum fields. According to QFT, fields permeate all of space, and particles are considered localized disturbances or fluctuations in these fields. Virtual particles, sometimes called "off-shell" particles, are one aspect of these quantum fluctuations.
The Heisenberg uncertainty principle states that there is an inherent uncertainty in the simultaneous measurement of certain pairs of physical quantities, such as position and momentum. This uncertainty is reflected in quantum field theory, where the energy of a field fluctuates over time due to the uncertainty principle.
These fluctuations can be visualized as the temporary creation and annihilation of particle-antiparticle pairs, known as virtual particles. These virtual particles do not correspond to physical particles that persist in time and can be directly observed. Instead, they exist only as temporary excitations of the underlying quantum fields.
Virtual particles are important in various phenomena, such as the scattering of particles in particle accelerators or the Casimir effect, which involves the interaction between fluctuating quantum fields and boundaries. They also play a role in the calculation of quantum corrections to physical processes, such as the electromagnetic interactions between charged particles.
It's important to note that virtual particles are a mathematical tool used within the framework of quantum field theory to describe and calculate physical processes. They are not directly observable and should not be confused with real, observable particles. Nevertheless, their inclusion in calculations and models has been remarkably successful in explaining and predicting a wide range of physical phenomena.