Vacuum-dressed cavity magnetotransport of a 2D electron gas

We present a theory predicting how the linear magnetotransport of a two-dimensional electron gas is modified by a passive electromagnetic cavity resonator where no real photons are injected nor created. For a cavity photon mode with in-plane linear polarization, the dc bulk magnetoresistivity of the 2D electron gas is anisotropic. In the regime of high filling factors of the Landau levels, the envelope of the Shubnikov-de Haas oscillations is profoundly modified and the resistivity can be increased or reduced depending on the system parameters. In the limit of low magnetic fields, the resistivity along the cavity-mode polarization direction is enhanced in the ultrastrong light-matter coupling regime. Our work shows the crucial role of virtual polariton excitations in controlling the dc charge transport properties of cavity-embedded systems.