Quantum metamaterials:Electromagnetic waves in Josephsonqubit lines

摘要

We consider the propagation of a classical electromagneticwave through a transmission line, formed by identical super-conducting charge qubits inside a superconducting resonator.Since the qubits can be in a coherent superposition of quan-tum states, we show that such a system demonstrates interest-ing new effects, such as a "breathing" photonic crystal with an oscillating bandgap. Similar behaviour is expected from atransmission line formed by flux qubits. The key ingredientof these effects is that the optical properties of the Josephsontransmission line are controlled by the quantum coherent stateof the qubits.