2,134 research outputs found
Hierarchical structure formation in layered superconducting systems with multi-scale inter-vortex interactions
No full textWe demonstrate the formation of hierarchical structures in two-dimensional systems with multiple length scales in the inter-particle interaction. These include states such as clusters of clusters, concentric rings, clusters inside a ring, and stripes in a cluster. We propose to realize such systems in vortex matter (where a vortex is mapped onto a particle with multi-scale interactions) in layered superconducting systems with varying inter-layer thicknesses and different layer materials
On the deflection of a positron beam by the miscut surface of an oriented crystal
No full textTrajectories of relativistic positrons moving in the electric field of oriented crystal near its surface have been simulated. A positron beam enters the field of the crystal at a small angle to crystallographic planes. Thus, planar channeling conditions are satisfied. The miscut surface of a crystal has a specific shape of a step sequence of terraces. It has been shown that such a surface can deflect a noticeable fraction of the beam from the crystal surface by means of quasichanneling. The possibility of the experimental observation of this phe nomenon has been analyzed
Deflection of positively charged heavy particles by the crystal miscut surface
No full textThe motion of relativistic nuclei which move near to a crystal surface was considered. The nuclei within a beam penetrate the crystal field at the small angle to the crystallographic planes, so the average field approximation and channeling phenomenology are valid. The crystal surface has a specific terrace-like form. It was shown the significant beam fraction could be deflected outwards from the surface due to quasichanneling
Ilyas Babaev, Gundula Mehnert, Florian Knauss. Die achaimenidische Residenz auf dem Gurban Tepe. Ausgrabungen bei Karačamirli. 3. Vorbericht
No full textLe bâtiment achéménide du Ideal Tepe, situé dans les environ de Karačamirli en Azerbaïdjan, était déjà exceptionnel bien avant la fin des fouilles. Il s’agit d’un propylée « copié » du Tripylon construit par Xerxès et Artaxerxès à Persepolis (Babaev et al., Ancient Civilizations from Scythia to Siberia 13, 2007, p. 31-45 et AMIT 38, 2006, p. 291-330). Quatre bases campaniformes sont encore in situ et l’emplacement de six autres a été reconnu À quelques centaines de mètres se trouve le site no..
Phase diagrams of vortex matter with multi-scale inter-vortex interactions in layered superconductors
No full textIt was recently proposed to use the stray magnetic fields of superconducting vortex lattices to trap ultracold atoms for building quantum emulators. This calls for new methods for engineering and manipulating of the vortex states. One of the possible routes utilizes type-1.5 superconducting layered systems with multi-scale inter-vortex interactions. In order to explore the possible vortex states that can be engineered, we present two phase diagrams of phenomenological vortex matter models with multi-scale inter-vortex interactions featuring several attractive and repulsive length scales. The phase diagrams exhibit a plethora of phases, including conventional 2D lattice phases, five stripe phases, dimer, trimer, and tetramer phases, void phases, and stable low-temperature disordered phases. The transitions between these states can be controlled by the value of an applied external field
Honeycomb, square, and kagome vortex lattices in superconducting systems with multiscale intervortex interactions
No full textThe recent proposal of Romero-Isart et al. [Phys. Rev. Lett. 111, 145304 (2013)] to utilize the vortex lattice phases of superconducting materials to prepare a lattice for ultracold-atom-based quantum emulators raises the need to create and control vortex lattices of different symmetries. Here we propose a mechanism by which honeycomb, hexagonal, square, and kagome vortex lattices could be created in superconducting systems with multiscale intervortex interactions. Multiple scales of the intervortex interaction can be created and controlled in layered systems made of different superconducting materials or with differing interlayer spacings
Muon-spin rotation measurements of the vortex state in Sr2RuO4 : type-1.5 superconductivity, vortex clustering, and a crossover from a triangular to a square vortex lattice
No full textThe authors acknowledge the financial support of the EPSRC (Grant No. EP/J01060X). All μSR experiments were carried out courtesy of the Paul Scherrer Institute. E. Babaev was supported by the US NSF CAREER Award No. DMR-0955902 and by the Knut and Alice Wallenberg Foundation through the Royal Swedish Academy of Sciences, Swedish Research Council.Muon-spin rotation has been used to probe the vortex state in Sr2RuO4. At moderate fields and temperatures a lattice of triangular symmetry is observed, crossing over to a lattice of square symmetry with increasing field and temperature. At lower fields it is found that there are large regions of the sample that are completely free from vortices which grow in volume as the temperature falls. Importantly this is accompanied by increasing vortex density and increasing disorder within the vortex-cluster-containing regions. Both effects are expected to result from the strongly temperature-dependent long-range vortex attractive forces arising from the multiband chiral-order superconductivity.Peer reviewe
Iceland and China: Strategic Partnership in the Arctic and Euro-Atlantic
No full textThe article analyses the development of China-Iceland relations which led to a full-scale political and economic partnership between the two countries, the current issues in Chinese policies towards Iceland, its plans to use the island as a starting point for expansion in Europe, Atlantic and Arctic regions. The paper explores the interests of the two states, stages of development of their relations, recent development with China’s return to Iceland after three years of the pandemic, and Chinese intentions to enhance the partnership in order to extend its influence in Arctics and Euro-Atlantics. This analysis sheds light on the Chinese policy in the Arctic which is important for the future of Russo-Chinese relations in the region, and on how the Chinese entrenchment in Northern Europe may change the balance of power and interest not only in the Arctic, but in the Euro-Atlantic region. The article reveals that China, as a non-Arctic state, is striving to intensify cooperation with Iceland, but the relations in recent years have begun to sour both due to the pressure from the United States and the EU, as well as pandemic restrictions. Despite Iceland's tense relations with the European partners and the United States and the active assistance of China, in the future Iceland may be inclined to choose the United States as a strategic partner
A determination of electroweak parameters at HERA
No full textUsing the deep inelastic e(+) p and e(-) p charged and neutral current scattering cross sections previously published, a combined electroweak and QCD analysis is performed to determine electroweak parameters accounting for their correlation with parton distributions. The data used have been collected by the HI experiment in 1994-2000 and correspond to an integrated luminosity of 117.2 pb(-1). A measurement is obtained of the W propagator mass in charged current ep scattering. The weak mixing angle sin(2)theta w is determined in the on-mass-shell renormalisation scheme. A first measurement at HERA is made of the light quark weak couplings to the Z(0) boson and a possible contribution of right-handed isospin components to the weak couplings is investigated
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