Bridging the terahertz gap for chaotic sources with superconducting junctions

Abstract

We observe a broadband chaotic signal of Terahertz frequency emitted from a superconducting junction. The generated radiation has a wide spectrum reaching 0.7 THz and power sufficient to drive on-chip circuit elements. To our knowledge, this is the first experimental observation of a highfrequency chaotic signal emitted by a superconducting system which lies inside the Terahertz gap. Our experimental finding is fully confirmed by the numerical modeling based on the microscopic theory and reveals the unrealized potential of superconducting systems in chaos-based Terahertz communication, fast generation of true random numbers and non-invasive Terahertz spectroscopy applicable to physical, chemical and biological systems. arXiv:1709.04052v3 [cond-mat.supr-con]

Electron Quantum Optics with Beam Splitters and Waveguides in Dirac Matter

“…[9,11] The splitting of the Josephson fluxons has been produced by creating relatively large geometries (e.g., a T-shape) of the long Josephson junction. [11,58] Using such fluxbeam splitting it was possible to create a new device producing chaotic THz signals, [16] therewith bridging the THz gap for chaotic sources. For a single electron the wave packet splitting may also lead to the formation of Majorana fermions, which are topologically stable massless elementary excitations and therewith become building blocks of future quantum computers.…”

“…[15] In graphene nanoribbons electrons are expected to act like photons in optical waveguides, without dissipation at the edges, or like fluxons in long Josephson junctions. [9][10][11][12][13][14][15][16] Only the presence of lattice defects and impurities may create dissipation at the edges of the material. Here the edges of a nanoribbon can guide electrons via edge states, which is an effect that is usually happening in a magnetic field (e.g., ref.…”

Electron quantum optics with beam splitters and waveguides in Dirac Matter

“…a T-shape) of the long Josephson junction [18]. Using such flux-beam splitting it was possible to create a new device producing chaotic THz signals [16], therewith bridging the THz gap for chaotic sources. For a single electron the wave packet splitting may also lead to the formation of Majorana fermions, which are topologicaly stable massless elementary excitations and therewith become building blocks of future quantum computers.…”

Response of a Cold-Electron Bolometer on THz Radiation from a Long YBa2Cu3O7−δ Bicrystal Josephson Junction

“…When the fluxon velocity u becomes close to the EM wave phase velocity c, a current step (velocity-matching or flux-flow step) appears at the current-voltage (IV) characteristic. While for low-T c Josephson junctions this regime was investigated both experimentally [24][25][26][27][28][29][30][31] and theoretically [32][33][34][35][36][37][38][39][40][41][42][43][44], there were just a few works for high-T c JJs in this regime [45][46][47][48], and their analysis was limited to the study of dc characteristics.…”