Free space

Categories: Electromagnetism | Quantum field theory | Physics stubs

In physics, free space is a concept of electromagnetic theory, corresponding to a perfect vacuum; the baseline state of the electromagnetic field..

Free space occurs in the expressions permittivity of free space and permeability of free space, where one defines the permittivity or permeability of a given material. In this setting it simply means no material present, and so corresponds to a theoretical idea of measurement carried out on a perfect vacuum.

Quantum field theory posits the presence of virtual particles which would prevent any part of the space-time continuum from being completely "empty."