You need energy to move the mirror that is used to create the photons.
In the report, it isn’t clear if the photons are released or not. If they are release it is not a reaction-less drive, it only throws a photon jet instead of an atomic jet. If the photons remain inside the cavity, the device violates the physics laws, and after building it they will find that they forget to include some little detail that makes the device not useful.
It is important to remember that quantum mechanics is strange and the Casimir effect is very strange, but none of them violates the conservation of momentum law. The problem with the conservation of momentum law is that to prove it, you only have to suppose that the space is invariant under translations (if you "move" the universe 1 foot to the "right", the physical laws don’t change), so any sensible physical theory comply with it.
In the report, it isn’t clear if the photons are released or not. If they are release it is not a reaction-less drive, it only throws a photon jet instead of an atomic jet. If the photons remain inside the cavity, the device violates the physics laws, and after building it they will find that they forget to include some little detail that makes the device not useful.
It is important to remember that quantum mechanics is strange and the Casimir effect is very strange, but none of them violates the conservation of momentum law. The problem with the conservation of momentum law is that to prove it, you only have to suppose that the space is invariant under translations (if you "move" the universe 1 foot to the "right", the physical laws don’t change), so any sensible physical theory comply with it.