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.

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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.

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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.

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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

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The current-phase relation in Josephson junctions

A special pulse tube cryocooler was designed and fabricated. Acceleration measurements show that the vibration of this cooler is much smaller than that of a Stirling machine. Two HTS microwave devices have been integrated with this cooler, which operate successfully as practical HTS sub-systems.

Demonstration of HTS microwave sub-systems with a pulse tube cryocooler

Low mechanical loss materials are needed to further decrease thermal noise in upcoming gravitational wave detectors. We present an analysis of the contribution of Akhieser and thermoelastic damping on the experimental results of resonant mechanical loss measurements. The combination of both processes allows the fit of the experimental data of quartz in the low temperature region (10K to 25K). A fully anisotropic numerical calculation over a wide temperature range (10K to 300 K) reveals, that thermoelastic damping is not a dominant noise source in bulk silicon samples. The anisotropic numerical calculation is sucessfully applied to the estimate of thermoelastic noise of an advanced LIGO sized silicon test mass.

Potential mechanical loss mechanisms in bulk materials for future gravitational wave detectors

Temperature-dependent transport characteristics of quasiballistic normal-metal-superconductor junctions

The model of synchronization of intrinsic Josephson junctions in a mesa structure of a high-temperature superconductor is developed. According to our model, the mesa structure does not consist of continuous layers but is divided into small stacks of layers. These stacks form the continuous environment which is considered as a transmission line. We showed that the conventional s-wave dynamic model for the Josephson junction and the d-wave dynamic model give nearly the same particularities in IV-characteristics. We showed also that the model describes numerically the dependence of the frequency of the coherent emission on the width of samples obtained in experiments.

https://robots.iopscience.iop.org/article/10.1088/1742-6596/507/4/042038/pdf

Coherent emission of intrinsic Josephson junctions

The Co ions pre-implanting process on Si(100) surface with low dose 10 15 –10 16 cm −2 at implantation energy 80 keV was used to grow smooth CoSi 2 films as buffer layers for the YBCO/CoSi 2 /(Co + )Si structure. The YBCO films have a critical temperature of T c off =86 K and T c on =80 K in the YBCO/CoSi 2 /(Co + )Si structure. Finally, Co distribution into reacted CoSi 2 layer was established as a result of the two contrary diffusion Co fluxes from Co film into Si bulk and from implanted layers to the Si surface. The ohmic contacts based on CoSi 2 /(Co + )Si and YBCO/CoSi 2 /(Co + )Si structures have a contact resistivity near 10 −5 Ω cm 2 at room temperature.

Paul Seidel

Papers

Demonstration of HTS microwave sub-systems with a pulse tube cryocooler

Potential mechanical loss mechanisms in bulk materials for future gravitational wave detectors

Temperature-dependent transport characteristics of quasiballistic normal-metal-superconductor junctions

Coherent emission of intrinsic Josephson junctions

CoSi2 buffer films on single crystal silicon with Co ions pre-implanted surface layer for YBCO/CoSi2/Si heterostructures