Quantum metamaterials: electromagnetic waves in a Josephson qubit line
journal contributionposted on 23.07.2013, 11:31 by Alexander L. Rakhmanov, Alexandre Zagoskin, Sergey Saveliev, Franco Nori
We consider the propagation of a classical electromagnetic wave through a transmission line, formed by identical superconducting charge qubits inside a superconducting resonator. Since the qubits can be in a coherent superposition of quantum states, we show that such a system demonstrates interesting effects, such as a “breathing” photonic crystal with an oscillating band gap and a “quantum Archimedean screw” that transports, at an arbitrary controlled velocity, Josephson plasma waves through a transmission line. The key ingredient of these effects is that the optical properties of the Josephson transmission line are controlled by the quantum coherent state of the qubits.