 Assuming homogeneous electric and magnetic fields, it is impossible for the EmDrive, or any other device, to extract a net momentum transfer from either a classical or quantum vacuum.Extraction of a net momentum "from nothing"
has been postulated in an inhomogeneous vacuum, but this remains highly controversial as it will violate Lorentz invariance.Both Harold White's
and Mike McCulloch's theories of how the EmDrive could work rely on these asymmetric or dynamical Casimir effects.