An international team of researchers has shown that superconductivity can be modified by coupling a superconductor to a dark electromagnetic cavity. The research opens the door to the control of a material’s properties by modifying its electromagnetic environment. Electronic structure defines many material properties – and this means that some properties can be changed by applying electromagnetic fields. The destruction of superconductivity by a magnetic field and the use of electric fields to control currents in semiconductors are two familiar examples. There is growing interest in how electronic properties could be controlled by placing a material in a dark electromagnetic cavity that resonates with an electronic transition in that material. In this scenario, an external field is not applied to the material. Rather, interactions occur via quantum vacuum fluctuations within the cavity.…