Effects of lasing in a one-dimensional quantum metamaterial

Electromagnetic pulse propagation in a quantum metamaterial, an artificial, globally quantum coherent optical medium, is numerically simulated. We show that a one-dimensional quantum metamaterial based on superconducting quantum bits, initialized in an easily reachable factorized excited state, demonstrates lasing in the microwave range, accompanied by the chaotization of qubit states and generation of higher harmonics. These effects may provide a tool for characterization and optimization of quantum metamaterial prototypes

Quasi-superradiant soliton state of matter in quantum metamaterials

Strong interaction of a system of quantum emitters (e.g., two-level atoms) with electromagnetic field induces specific correlations in the system accompanied by a drastic insrease of emitted radiation (superradiation or superfluorescence). Despite the fact that since its prediction this phenomenon was subject to a vigorous experimental and theoretical research, there remain open question, in particular, concerning the possibility of a first order phase transition to the superradiant state from the vacuum state. In systems of natural and charge-based artificial atome this transition is prohibited by "no-go" theorems. Here we demonstrate numerically a similar transition in a one-dimensional quantum metamaterial - a chain of artificial atoms (qubits) strongly interacting with classical electromagnetic fields in a transmission line. The system switches from vacuum state with zero classical electromagnetic fields and all qubits being in the ground state to the quasi-superradiant (QS) phase with one or several magnetic solitons and finite average occupation of qubit excited states along the transmission line. A quantum metamaterial in the QS phase circumvents the "no-go" restrictions by considerably decreasing its total energy relative to the vacuum state by exciting nonlinear electromagnetic solitons with many nonlinearly coupled electromagnetic modes in the presence of external magnetic field

Study Of Coherent And Continuous Terahertz Wave Emission In Equilateral Triangular Mesas Of Superconducting Bi2Sr2Cacu 2O8+Δ Intrinsic Josephson Junctions

We report on intense and coherent terahertz (THz) electromagnetic (EM) waves emitted from equilateral triangular mesa structures of the intrinsic Josephson junctions (IJJs) in single crystalline high-Tc superconducting Bi2Sr2CaCu2O 8+δ. The focused ion beam milling technique is used for mesa fabrication. THz radiation is observed when the emission frequency is in the vicinity of the primary cavity resonance frequency determined by the mesa geometry. We also investigated numerically the THz radiation from such mesas using the finite difference time domain method. We found an apparent EM mode similar to the known TM(1, 0) = TM(0, 1) cavity mode during the THz emission. © 2013 Elsevier Ltd. All rights reserved