Multi-Atom Quasiparticle Scattering Interference for Superconductor Energy-Gap Symmetry Determination

Complete theoretical understanding of the most complex superconductors requires a detailed knowledge of the symmetry of the superconducting energy-gap $\Delta_\mathbf{k}^\alpha$, for all momenta $\mathbf{k}$ on the Fermi surface of every band $\alpha$. While there are a variety of techniques for determining $|\Delta_\mathbf{k}^\alpha|$, no general method existed to measure the signed values of $\Delta_\mathbf{k}^\alpha$. Recently, however, a new technique based on phase-resolved visualization of superconducting quasiparticle interference (QPI) patterns centered on a single non-magnetic impurity atom, was introduced. In principle, energy-resolved and phase-resolved Fourier analysis of these images identifies wavevectors connecting all k-space regions where $\Delta_\mathbf{k}^\alpha$ has the same or opposite sign. But use of a single isolated impurity atom, from whose precise location the spatial phase of the scattering interference pattern must be measured is technically difficult. Here we introduce a generalization of this approach for use with multiple impurity atoms, and demonstrate its validity by comparing the $\Delta_\mathbf{k}^\alpha$ it generates to the $\Delta_\mathbf{k}^\alpha$ determined from single-atom scattering in FeSe where $s_{\pm}$ energy-gap symmetry is established. Finally, to exemplify utility, we use the multi-atom technique on LiFeAs and find scattering interference between the hole-like and electron-like pockets as predicted for $\Delta_\mathbf{k}^\alpha$ of opposite sign

Multi-atom quasiparticle scattering interference for superconductor energy-gap symmetry determination

Complete theoretical understanding of the most complex superconductors requires a detailed knowledge of the symmetry of the superconducting energy-gap Δ$\frac{α}{k}$, for all momenta k on the Fermi surface of every band α. While there are a variety of techniques for determining |Δ$\frac{α}{k}$|, no general method existed to measure the signed values of Δ$\frac{α}{k}$. Recently, however, a technique based on phase-resolved visualization of superconducting quasiparticle interference (QPI) patterns, centered on a single non-magnetic impurity atom, was introduced. In principle, energy-resolved and phase-resolved Fourier analysis of these images identifies wavevectors connecting all k-space regions where Δ$\frac{α}{k}$ has the same or opposite sign. But use of a single isolated impurity atom, from whose precise location the spatial phase of the scattering interference pattern must be measured, is technically difficult. Here we introduce a generalization of this approach for use with multiple impurity atoms, and demonstrate its validity by comparing the Δ$\frac{α}{k}$ it generates to the Δ$\frac{α}{k}$ determined from single-atom scattering in FeSe where s± energy-gap symmetry is established. Finally, to exemplify utility, we use the multi-atom technique on LiFeAs and find scattering interference between the hole-like and electron-like pockets as predicted for Δ$\frac{α}{k}$ of opposite sign

ArDO: An ontology to describe the dynamics of multimedia archival records

Cultural heritage institutions store and digitize large amounts of multimedia data inside archives to make archival records findable by archivists, scientists, and general public. Cataloging standards vary from archive to archive and, therefore, the sharing and use of this data are limited. To solve this issue, linked open data (LOD) is rising as an essential paradigm to open and provide access to the archival resources. Archives which are opened to the world knowledge benefit from external connections by enabling the application of automated approaches to process archival records, helping all stakeholders to gain valuable insights. In this paper, we present the Archive Dynamics Ontology (ArDO) - an ontology designed for describing the hierarchical nature of archival multimedia data, as well as its application on the example of archival resources about the Weimar Republic. Furthermore, ArDO semantically organizes multimedia archival resources in form of texts, images, audios, and videos by representing the dynamics related to their classification over time. ArDO tracks the changes of a specific hierarchical classification schema referred to as systematics adopted to organize archival resources under semantically defined keywords

Gynecomastia: Evaluation and Surgical Tips and Tricks

Gynecomastia, excess development of the male breast, is a common deformity encountered by plastic surgeons. It is the most common breast alteration in males, commonly developing without a pathologic basis during periods of physiologic change such as infancy, puberty, and old age. It may accompany a wide variety of systemic and metabolic diseases, and it may be drug induced. Given the number of pathophysiologic mechanisms, detailed presurgical workup is essential prior to determining whether surgical management is appropriate. This chapter highlights different surgical techniques performed in our practice, along with standardized preoperative evaluation and postoperative care. We believe that a dynamic approach to patients with gynecomastia decreases common complications and increases patient satisfaction in various degrees of gynecomastia. This chapter includes some “tricks” we use during our markings, preoperative steps, and intraoperative approaches that help us optimize patient safety, while maintaining operative efficacy and improving aesthetic outcomes in gynecomastia

Multi-atom quasiparticle scattering interference for superconductor energy-gap symmetry determination

Complete theoretical understanding of the most complex superconductors requires a detailed knowledge of the symmetry of the superconducting energy-gap Δkα, for all momenta k on the Fermi surface of every band α. While there are a variety of techniques for determining ∣Δkα∣, no general method existed to measure the signed values of Δkα. Recently, however, a technique based on phase-resolved visualization of superconducting quasiparticle interference (QPI) patterns, centered on a single non-magnetic impurity atom, was introduced. In principle, energy-resolved and phase-resolved Fourier analysis of these images identifies wavevectors connecting all k-space regions where Δkα has the same or opposite sign. But use of a single isolated impurity atom, from whose precise location the spatial phase of the scattering interference pattern must be measured, is technically difficult. Here we introduce a generalization of this approach for use with multiple impurity atoms, and demonstrate its validity by comparing the Δkα it generates to the Δkα determined from single-atom scattering in FeSe where s± energy-gap symmetry is established. Finally, to exemplify utility, we use the multi-atom technique on LiFeAs and find scattering interference between the hole-like and electron-like pockets as predicted for Δkα of opposite sign