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Full-Text Articles in Physics
Dynamical Conductivity At The Dirty Superconductor-Metal Quantum Phase Transition, Adrian Del Maestro, Bernd Rosenow, Jose A. Hoyos, Thomas Vojta
Dynamical Conductivity At The Dirty Superconductor-Metal Quantum Phase Transition, Adrian Del Maestro, Bernd Rosenow, Jose A. Hoyos, Thomas Vojta
Physics Faculty Research & Creative Works
We study the transport properties of ultrathin disordered nanowires in the neighborhood of the superconductor-metal quantum phase transition. To this end we combine numerical calculations with analytical strong-disorder renormalization group results. The quantum critical conductivity at zero temperature diverges logarithmically as a function of frequency. In the metallic phase, it obeys activated scaling associated with an infinite-randomness quantum critical point. We extend the scaling theory to higher dimensions and discuss implications for experiments.
Anomalously Elastic Intermediate Phase In Randomly Layered Superfluids, Superconductors, And Planar Magnets, Priyanka Mohan, Paul M. Goldbart, Rajesh Narayanan, John Toner, Thomas Vojta
Anomalously Elastic Intermediate Phase In Randomly Layered Superfluids, Superconductors, And Planar Magnets, Priyanka Mohan, Paul M. Goldbart, Rajesh Narayanan, John Toner, Thomas Vojta
Physics Faculty Research & Creative Works
We show that layered quenched randomness in planar magnets leads to an unusual intermediate phase between the conventional ferromagnetic low-temperature and paramagnetic high-temperature phases. In this intermediate phase, which is part of the Griffiths region, the spin-wave stiffness perpendicular to the random layers displays anomalous scaling behavior, with a continuously variable anomalous exponent, while the magnetization and the stiffness parallel to the layers both remain finite. Analogous results hold for superfluids and superconductors. We study the two phase transitions into the anomalous elastic phase, and we discuss the universality of these results, and implications of finite sample size as well …
Miniaturized Superconducting Metamaterials For Radio Frequencies, Cihan Kurter, John A. Abrahams, Steven Mark Anlage
Miniaturized Superconducting Metamaterials For Radio Frequencies, Cihan Kurter, John A. Abrahams, Steven Mark Anlage
Physics Faculty Research & Creative Works
We have developed a low-loss, ultrasmall radio frequency (rf) metamaterial operating at ~76 MHz. This miniaturized medium is made up of planar spiral elements with diameter as small as ~λ/658 (λ is the free space wavelength), fashioned from Nb thin films on quartz substrates. The transmission data are examined below and above the superconducting transition temperature of Nb for both a single spiral and a one dimensional array. The validity of the design is tested through numerical simulations and good agreement is found. We discuss how superconductors enable such a compact design in the rf with high loaded-quality factor (in …