There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This book presents the conceptual framework underlying the atomistic theory of matter, emphasizing those aspects that relate to current flow. This includes some of the most advanced concepts of non-equilibrium quantum statistical mechanics. No prior acquaintance with quantum mechanics is assumed. Chapter 1 provides a description of quantum transport in elementary terms accessible to a beginner. The book then works its way from hydrogen to nanostructures, with extensive coverage of current flow. The final chapter summarizes the equations for quantum transport with illustrative examples showing how conductors evolve from the atomic to the ohmic regime as they get larger. Many numerical examples are used to provide concrete illustrations and the corresponding Matlab codes can be downloaded from the web. Videostreamed lectures, keyed to specific sections of the book, are also available through the web. This book is primarily aimed at senior and graduate students.

/pdf/quantum-transport-atom-to-transistor-2r826n1ghz.pdf

Quantum Transport: Atom to Transistor

Advanced gravitational wave interferometers, currently under realization, will soon permit the detection of gravitational waves from astronomical sources. To open the era of precision gravitational wave astronomy, a further substantial improvement in sensitivity is required. The future space-based Laser Interferometer Space Antenna and the third-generation ground-based observatory Einstein Telescope (ET) promise to achieve the required sensitivity improvements in frequency ranges. The vastly improved sensitivity of the third generation of gravitational wave observatories could permit detailed measurements of the sources' physical parameters and could complement, in a multi-messenger approach, the observation of signals emitted by cosmological sources obtained through other kinds of telescopes. This paper describes the progress of the ET project which is currently in its design study phase.

/pdf/the-einstein-telescope-a-third-generation-gravitational-wave-2hg484mq8f.pdf

The Einstein Telescope: a third-generation gravitational wave observatory

The Advanced LIGO gravitational wave detectors are next generation instruments which will replace the existing initial LIGO detectors. They are currently being constructed and installed. Advanced LIGO strain sensitivity is designed to be about a factor 10 better than initial LIGO over a broad band and usable to 10 Hz, in contrast to 40 Hz for initial LIGO. This is expected to allow for detections and significant astrophysics in most categories of gravitational waves. To achieve this sensitivity, all hardware subsystems are being replaced with improvements. Designs and expected performance are presented for the seismic isolation, suspensions, optics and laser subsystems. Possible enhancements to Advanced LIGO, either to resolve problems that may arise and/or to allow for improved performance, are now being researched. Some of these enhancements are discussed along with some potential technology being considered for detectors beyond Advanced LIGO.

/pdf/advanced-ligo-the-next-generation-of-gravitational-wave-2jqom9m7qe.pdf

Advanced LIGO: the next generation of gravitational wave detectors

This review provides a theoretical basis for understanding the current-phase relation (CPhiR) for the stationary (dc) Josephson effect in various types of superconducting junctions The authors summarize recent theoretical developments with an emphasis on the fundamental physical mechanisms of the deviations of the CPhiR from the standard sinusoidal form A new experimental tool for measuring the CPhiR is described and its practical applications are discussed The method allows one to measure the electrical currents in Josephson junctions with a small coupling energy as compared to the thermal energy A number of examples illustrate the importance of the CPhiR measurements for both fundamental physics and applications

/pdf/the-current-phase-relation-in-josephson-junctions-40zrgv4v2s.pdf

The current-phase relation in Josephson junctions

Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 1 Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 2 Institute for Optics and Quantum Electronics, Friedrich Schiller University, D-07743 Jena, Germany 3 Helmholtz Institute Jena, D-07743 Jena, Germany 4 GSI Helmholtz Center for Heavy Ion Research, D-64291 Darmstadt, Germany 5 The Cockcroft Institute, University of Liverpool, Daresbury, Cheshire WA4 4AD, U.K 6 CERN European Organization for Nuclear Research, CH-1211 Geneva, Switzerland

/pdf/physical-society-of-japan-superconducting-beam-charge-2ktxplffz6.pdf

Physical Society of Japan : Superconducting beam charge monitors for antiproton storage rings

Coherent charge and spin transport of entangled electron waves across a three-terminal setup formed by a charge emitter and two drain wires with a superconducting inset in one of them and a perfect absorber or a spin filter in the other is theoretically discussed. We show that self-controlled charge and spin currents across the device can be realized by employing highly nonlinear dispersion relation in the near-gap energy range of a superconductor.

Quantum Interference and Entanglement Effects in Hybrid Three-Terminal Splitters

The nature of resistance peaks in the HTSC tunneling characteristics is interpreted in terms of quantum finite-size effects in a narrow conducting channel containing a small number of scatters.

Anomalous conductance dip structure in HTSC heterocontacts

To investigate the properties of iron-based superconductors, we examined different kinds of Josephson junctions using Co-doped Ba-122 thin films. Based on bicrystalline SrTiO3 substrates we prepared grain boundary (GB) junctions, which showed clear Josephson effects. We present electrical measurements at varying temperatures and magnetic fields. Furthermore, we prepared hybrid junctions using thin film technique. Confined by a Ba-122 base electrode (S) and a PbIn counter electrode (S') two different geometries of hybrid junctions are formed: a planar SNS' junction with a gold barrier (N) in between and an edge-type junction with an interface-engineered barrier. All three kinds of junctions showed asymmetric resistively shunted junction-like (RSJ) behavior with ICRN products of 20.2 /mu V (GB junctions), 18.4 /mu V (planar SNS' junctions) and 12.3 /mu V (edge-type junctions), respectively. An excess current could be observed at all junctions.

Bicrystalline Grain Boundary and Hybrid SNS Junctions Based on Ba-122 Thin Films

We have measured point contacts with a gold tip on Bi2Sr2CaCu2O8+y thin films and Bi2Sr2CaCu2O8+y/SrTiO3 double layers. The results show tunneling or direct conductivity behaviour depending on the junction parameters and can be fitted by corresponding theoretical models. From fitting procedure of differential characteristics by modified Blonder-Tinkham-Klapwijk (BTK) theory the Fermi velocity vF=5×105 m/s, ratio 2Δ(4.2K)/kTc=7.9 and coherence length ξab=3.5 nm were obtained. The changing of the interface transmission by additional layers of different thickness corresponding to metallic or insulating behaviour is shown. In the frame of the inelastic scattering of quasiparticles the linear background of differential conductance is discussed.

Paul Seidel

Papers

Physical Society of Japan : Superconducting beam charge monitors for antiproton storage rings

Quantum Interference and Entanglement Effects in Hybrid Three-Terminal Splitters

Anomalous conductance dip structure in HTSC heterocontacts

Bicrystalline Grain Boundary and Hybrid SNS Junctions Based on Ba-122 Thin Films

Point contact investigation on Bi2Sr2CaCu2O8+y thin films