Magnetic response of an electron gas in a quantum ring of non-zero width

An investigation of the magnetic moment of an electron gas in a quantum ring of non-zero width is made. Analytic expressions are obtained for the magnetic moment. For the magnetic moment of the system, the dependence on temperature and parameters of the ring are found and investigated in detail. De Haas–van Alphen and Aharonov–Bohm oscillations are investigated.     

Flow-Assisted Self-Organization of Hybrid Membranes

Microfluidic flows are a powerful tool to drive reactions far from equilibrium and, thus, induce chemical selforganization. Studies of membrane formation in microfluidic devices have been limited to non-redox and purely inorganic reactions. Here, the formation of hybrid membranes at the interface of AgNO₃ and 3,3′,5,5′-tetramethylbenzidine solutions, which are steadily co-injected into a microfluidic device, is reported. The membrane thickening occurs in both directions and reveals oscillatory dynamics. The hybrid membrane mainly consists of hair-like Ag microstructures, Ag nanowires, and unbranched TMB–TMB²⁺ microfibers. Branched dendrite-like fibers form on the TMB side when the flow is stopped. These components were characterized with techniques including micro-Raman and energy dispersive X-ray spectroscopy as well as scanning electron microscopy. The effects of initial concentration ratios on the membrane thickening speed and its opaqueness were also studied.     

Transport and Magnetotransport in the New Quasi-Two-Dimensional Organic Metal (BETS)2ZnBr4(C6H4Cl2) with Different Electron Structure of Neighboring Cation Layers

Intralayer and interlayer transports and Shubnikov – de Haas oscillations are investigated in the new dual-layered organic metal (BETS)₄ZnBr₄(C₆H₄Cl₂). It is shown that: a) the interlayer resistance behavior corresponds to incoherent transport; b) the behavior of quantum oscillations is well described by the model of a coherent network of magnetic breakdown orbits. Both the interlayer transport and quantum oscillations are in a good agreement with the theoretical calculation of the zone structure.     

A simple hybrid finite volume solver for compressible turbulence

A simple, explicit, hybrid finite volume method for simulating compressible turbulence is developed by combining a fourth‐order central scheme and a shock‐capturing simple low‐dissipation advection upstream splitting method. The total flux on each of the cell faces is computed as a weighted average of central/nondissipative and upwind/dissipative fluxes. The weights are determined using an unphysical oscillation sensor in addition to a more traditional discontinuity sensor used in earlier studies. Shocks are well captured, but overshoots in density are predicted around contact discontinuities that are normal to the flow. The use of the latter sensor effectively prevents these overshoots from generating spurious oscillations that travel away from the contact lines. The efficacy of the proposed method for direct or large‐eddy simulations of supersonic turbulence is established using several canonical test problems. Copyright © 2015 John Wiley & Sons, Ltd.     

Explaining LSND and MiniBooNE using altered neutrino dispersion relations

We investigate the possibility of explaining the MiniBooNE anomaly using CPT-and Lorentz-symmetry-violating neutrino-antineutrino oscillations in a two-generation framework. We work with four non-zero CPT-violating parameters that allow for resonant enhancements in neutrino-antineutrino oscillation phenomena in vacuo which are suitably described in terms of charge conjugation eigenstates of the system. We study the relations among the flavor, charge conjugation and mass eigenbases of neutrino-antineutrino oscillations and examine the interplay between the available CPT-violating parameter space and possible resonance structures.     

A Simple Generalized Excitability Model Mimicking Salient Features of Neuron Dynamics

A generalization of the FitzHugh—Nagumo model for excitability is provided to account for salient features of Inferior Olive neurons. The base state is a limit cycle and excitability appears as spiking over peaks of the oscillations. The response of the model to various types of external stimulus is also presented. In particular, we show the relevance of an appropriate balance between amplitude and duration of the stimulus.     

Transverse oscillations for tissue motion estimation

This paper gives an overview of the methods developed for tissue motion estimation using transverse oscillation images (TO). TO images are specific radiofrequency ultrasound images featuring oscillations in both spatial directions. The initial studies on TO were published in the late 1990s. This paper reviews the main ideas and applications behind this motion estimation approach. First the origin and motivation of TO is briefly reviewed. Then the beamforming methods that lead to TO images are given, detailing the receive-only approach and the transmit-and-receive approach using synthetic aperture data. The different medical applications where TO has been used are discussed (blood flow, elastography and echocardiography), showing how it can improve motion estimation. Finally, the future perspectives of TO are outlined.     

Modification of Landau Levels in a 2D Ring Due to Rotation Effects and Edge States

The properties of a 2D quantum ring under rotating and external magnetic field effects are investigated. The Landau levels and their inertial effects on them are initially analyzed. Among the results obtained, it is emphasized that the rotation lifted the degeneracy of Landau levels. The second part deals with the electronic confinement in a 2D ring modeled by a hard wall potential. The eigenstates are described by Landau states as long as they are not too close to the ring edges. On the other hand, near the ring edges, the energies increase monotonically. These states are known as edge states. Edge states have a significant role in the physical properties of the ring. Thus, the Fermi energy and magnetization are analyzed. In the specific case of magnetization, two approaches are considered. In the first approach, an analytical result for magnetization is obtained but without considering rotation. Numerical results show the de Haas-Van Alphen (dHvA) oscillations. In the second approach, rotating effects are considered. In addition to the dHvA oscillations, the Aharonov–Bohm-type (AB) oscillations are verified, which are associated with the presence of edge states. The effects of rotation on the results are discussed and it is found that rotation is responsible for inducing AB oscillations.     

Observation of π Berry phase in quantum oscillations of three‐dimensional Fermi surface in topological insulator Bi2Se3

We report the quantum transport studies on Bi₂Se₃ single crystal with bulk carrier concentration of ～10¹⁹ cm^–3. The Bi₂Se₃ crystal exhibits metallic character, and at low temperatures, the field dependence of resistivity shows clear Shubnikov–de Haas (SdH) oscillations above 6 T. The analysis of these oscillations through Lifshitz–Kosevich theory reveals a non‐trivial π Berry phase coming from three‐dimensional (3D) Fermi surface, which is a strong signature of Dirac fermions with three‐dimensional dispersion. The large Dingle temperature and non zero slope of Williamson–Hall plot suggest the presence of enhanced local strain field in our system which possibly transforms the regions of topological insulator to 3D Dirac fermion metal state. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)