Single-particle subband structure of Quantum Cables

We proposed a model of Quantum Cable in analogy to the recently synthesized coaxial nanocable structure [Suenaga et al. Science, 278, 653 (1997); Zhang et al. ibid, 281, 973 (1998)], and studied its single-electron subband structure. Our results show that the subband spectrum of Quantum Cable is different from either double-quantum-wire (DQW) structure in two-dimensional electron gas (2DEG) or single quantum cylinder. Besides the double degeneracy of subbands arisen from the non-abelian mirrow reflection symmetry, interesting quasicrossings (accidental degeneracies), anticrossings and bundlings of Quantum Cable energy subbands are observed for some structure parameters. In the extreme limit (barrier width tends to infinity), the normal degeneracy of subbands different from the DQW structure is independent on the other structure parameters.Comment: 12 pages, 9 figure

Quantum Cable as transport spectroscopy of 1D DOS of cylindrical quantum wires

We considered the proposed Quantum Cable as a kind of transport spectroscopy of one-dimensional (1D) density of states (DOS) of cylindrical quantum wires. By simultaneously detecting the direct current through the cylindrical quantum wire and the leaked tunneling current into the neighboring wire at desired temperatures, one can obtain detailed information about 1D DOS and subband structure of cylindrical quantum wires.Comment: 7 pages, 4 figures, late

Thermodynamics of modified black holes from gravity's rainbow

We study the thermodynamics of modified black holes proposed in the context of gravity's rainbow. A notion of intrinsic temperature and entropy for these black holes is introduced. In particular for a specific class of modified Schwarzschild solutions, their temperature and entropy are obtained and compared with those previously obtained from modified dispersion relations in deformed special relativity. It turns out that the results of these two different strategies coincide, and this may be viewed as a support for the proposal of deformed equivalence principle.Comment: 3 pages, Revte

Ballistic electronic transport in Quantum Cables

We studied theoretically ballistic electronic transport in a proposed mesoscopic structure - Quantum Cable. Our results demonstrated that Qauntum Cable is a unique structure for the study of mesoscopic transport. As a function of Fermi energy, Ballistic conductance exhibits interesting stepwise features. Besides the steps of one or two quantum conductance units ($2e^2/h$), conductance plateaus of more than two quantum conductance units can also be expected due to the accidental degeneracies (crossings) of subbands. As structure parameters is varied, conductance width displays oscillatory properties arising from the inhomogeneous variation of energy difference betweeen adjoining transverse subbands. In the weak coupling limits, conductance steps of height $2e^2/h$ becomes the first and second plateaus for the Quantum Cable of two cylinder wires with the same width.Comment: 11 pages, 5 figure

Superconductivity mediated by the antiferromagnetic spin-wave in chalcogenide iron-base superconductors

The ground state of K$_{0.8+x}$Fe$_{1.6+y}$Se$_2$ and other iron-based selenide superconductors are doped antiferromagnetic semiconductors. There are well defined iron local moments whose energies are separated from those of conduction electrons by a large band gap in these materials. We propose that the low energy physics of this system is governed by a model Hamiltonian of interacting electrons with on-site ferromagnetic exchange interactions and inter-site superexchange interactions. We have derived the effective pairing potential of electrons under the linear spin-wave approximation and shown that the superconductivity can be driven by mediating coherent spin wave excitations in these materials. Our work provides a natural account for the coexistence of superconducting and antiferromagnetic long range orders observed by neutron scattering and other experiments.Comment: 4 pages, 3 figure

Secure Wireless Communications Based on Compressive Sensing: A Survey

IEEE Compressive sensing (CS) has become a popular signal processing technique and has extensive applications in numerous fields such as wireless communications, image processing, magnetic resonance imaging, remote sensing imaging, and anology to information conversion, since it can realize simultaneous sampling and compression. In the information security field, secure CS has received much attention due to the fact that CS can be regarded as a cryptosystem to attain simultaneous sampling, compression and encryption when maintaining the secret measurement matrix. Considering that there are increasing works focusing on secure wireless communications based on CS in recent years, we produce a detailed review for the state-of-the-art in this paper. To be specific, the survey proceeds with two phases. The first phase reviews the security aspects of CS according to different types of random measurement matrices such as Gaussian matrix, circulant matrix, and other special random matrices, which establishes theoretical foundations for applications in secure wireless communications. The second phase reviews the applications of secure CS depending on communication scenarios such as wireless wiretap channel, wireless sensor network, internet of things, crowdsensing, smart grid, and wireless body area networks. Finally, some concluding remarks are given

Gaussian-Gamma collaborative filtering: a hierarchical Bayesian model for recommender systems

The traditional collaborative filtering (CF) suffers from two key challenges, namely, the normal assumption that it is not robust, and it is difficult to set in advance the penalty terms of the latent features. We therefore propose a hierarchical Bayesian model-based CF and the related inference algorithm. Specifically, we impose a Gaussian-Gamma prior on the ratings, and the latent features. We show the model is more robust, and the penalty terms can be adapted automatically in the inference. We use Gibbs sampler for the inference and provide a statistical explanation. We verify the performance using both synthetic and real dataset

A new consideration for the coupled ocean-acoustic modeling

Based on the review of the computational ocean acoustic propagation modeling, the paper put forward a new consideration for the coupled ocean-acoustic modeling from the perspective of energy transfer. In respect that the classical models of acoustic propagation just regard the variation of the seawater as the force term which is sometimes experimental and have to discuss various situations when the ocean is dynamically complex or unclear, the new consideration makes use of the coupled ocean-acoustic modeling and a recent method in ocean dynamics study ??? multiscale energy and vorticity analysis (MS-EVA). In MS-EVA, the energy transfer can be calculated which called ???canonical transfer???. After applying canonical transfer to couple the conversion of the acoustic energy and the energy of seawater such as kinetic energy, the energy transfer can be utilized to amend the initial acoustic propagation. This new\ud consideration has many advantages as well as some difficulties to carry out. If it comes true, it makes sense for acoustic propagation modeling in complex or even unclear dynamics ocean

HST and LAMOST discover a dual active galactic nucleus in J0038+4128

We report the discovery of a kiloparsec-scale dual active galactic nucleus (AGN) in J0038+4128. From the Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, we find two optical nuclei with a projection separation of 4.7 kpc (3.44 arcsec). The southern component (J0038+4128S) is spectroscopically observed with the HST Goddard High Resolution Spectrograph in the UV range and is found to be a Seyfert 1 galaxy with a broad Ly alpha emission line. The northern component (J0038+4128N) is spectroscopically observed during the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (also named the Guoshoujing Telescope) pilot survey in the optical range. The observed line ratios as well as the consistency of redshift of the nucleus emission lines and the host galaxy's absorption lines indicate that J0038+4128N is a Seyfert 2 galaxy with narrow lines only. These results thus confirm that J0038+4128 is a Seyfert 1-Seyfert 2 AGN pair. The HST WFPC2 F336W/U-band image of J0038+4128 also reveals for the first time for a dual AGN system two pairs of bi-symmetric arms, as are expected from the numerical simulations of such system. Being one of a few confirmed kiloparsec-scale dual AGNs exhibiting a clear morphological structure of the host galaxies, J0038+4128 provides an unique opportunity to study the co-evolution of the host galaxies and their central supermassive black holes undergoing a merging process.Comment: 6 pages, 4 figures, 2 tables, Accepted for publication in MNRAS Letter