Double-Layer Bose-Einstein Condensates with Large Number of Vortices

In this paper we systematically study the double layer vortex lattice model, which is proposed to illustrate the interplay between the physics of a fast rotating Bose-Einstein condensate and the macroscopic quantum tunnelling. The phase diagram of the system is obtained. We find that under certain conditions the system will exhibit one novel phase transition, which is consequence of competition between inter-layer coherent hopping and inter-layer density-density interaction. In one phase the vortices in one layer coincide with those in the other layer. And in another phase two sets of vortex lattices are staggered, and as a result the quantum tunnelling between two layers is suppressed. To obtain the phase diagram we use two kinds of mean field theories which are quantum Hall mean field and Thomas-Fermi mean field. Two different criteria for the transition taking place are obtained respectively, which reveals some fundamental differences between these two mean field states. The sliding mode excitation is also discussed.Comment: 12 pages, 8 figure

On the error term in Weyl's law for the Heisenberg manifolds (II)

In this paper we study the mean square of the error term in the Weyl's law of an irrational $(2l+1)$-dimensional Heisenberg manifold . An asymptotic formula is established

A Wave Function Describing Superfluidity in a Perfect Crystal

We propose a many-body wave function that exhibits both diagonal and off-diagonal long-range order. Incorporating short-range correlations due to interatomic repulsion, this wave function is shown to allow condensation of zero-point lattice vibrations and phase rigidity. In the presence of an external velocity field, such a perfect crystal will develop non-classical rotational inertia, exhibiting the supersolid behavior. In a sample calculation we show that the superfluid fraction in this state can be as large as of order 0.01 in a reasonable range of microscopic parameters. The relevance to the recent experimental evidence of a supersolid state by Chan and Kim is discussed.Comment: final version to be published in Journal of Statistical Mechanics: Theory and Experimen

Magnetically asymmetric interfaces in a (LaMnO3_3)/(SrMnO3_3) superlattice due to structural asymmetries

Polarized neutron reflectivity measurements of a ferromagnetic [(LaMnO$_3$)$_{11.8}$/(SrMnO$_3$)$_{4.4}$]$_6$ superlattice reveal a modulated magnetic structure with an enhanced magnetization at the interfaces where LaMnO$_3$ was deposited on SrMnO$_3$ (LMO/SMO). However, the opposite interfaces (SMO/LMO) are found to have a reduced ferromagnetic moment. The magnetic asymmetry arises from the difference in lateral structural roughness of the two interfaces observed via electron microscopy, with strong ferromagnetism present at the interfaces that are atomically smooth over tens of nanometers. This result demonstrates that atomic-scale roughness can destabilize interfacial phases in complex oxide heterostructures.Comment: 5 pages, 4 figure

Onset of dielectric modes at 110K and 60K due to local lattice distortions in non-superconducting YBa_{2}Cu_{3}O_{6.0} crystals

We report the observation of two dielectric transitions at 110K and 60K in the microwave response of non-superconducting YBa_{2}Cu_{3}O_{6.0} crystals. The transitions are characterized by a change in polarizability and presence of loss peaks, associated with overdamped dielectric modes. An explanation is presented in terms of changes in polarizability of the apical O atoms in the Ba-O layer, affected by lattice softening at 110K, due to change in buckling of the Cu-O layer. The onset of another mode at 60K strongly suggests an additional local lattice change at this temperature. Thus microwave dielectric measurements are sensitive indicators of lattice softening which may be relevant to superconductivity.Comment: 5 pages, 3 ps format figure

Performance data of US Naval Observatory VLG-11 hydrogen masers since September, 1983

In 1983, two VLC-11 masers were delivered to the U.S. Naval Observatory by the Smithsonian Astrophysical Observatory. Last year the short-term stability of these masers was reported and the effect of this short-term stability on timekeeping performance was examined. Since the date of installation, 13 September 1983, data on the masers' long-term performance have been accumulated. The Allan variance, agma(tau), of the relative frequency between the masers reaches a minimum of about 4 parts in 10 to the 16th power at averaging times 5,000 seconds and rises at longer averaging times due, at least partly, to systematic frequency drift. The systematic frequency drifts, expressed in units of fractional frequency difference per day are discussed

Resilient routing mechanism for wireless sensor networks with deep learning link reliability prediction

Wireless sensor networks play an important role in Internet of Things systems and services but are prone and vulnerable to poor communication channel quality and network attacks. In this paper we are motivated to propose resilient routing algorithms for wireless sensor networks. The main idea is to exploit the link reliability along with other traditional routing metrics for routing algorithm design. We proposed firstly a novel deep-learning based link prediction model, which jointly exploits Weisfeiler-Lehman kernel and Dual Convolutional Neural Network (WL-DCNN) for lightweight subgraph extraction and labelling. It is leveraged to enhance self-learning ability of mining topological features with strong generality. Experimental results demonstrate that WL-DCNN outperforms all the studied 9 baseline schemes over 6 open complex networks datasets. The performance of AUC (Area Under the receiver operating characteristic Curve) is improved by 16% on average. Furthermore, we apply the WL-DCNN model in the design of resilient routing for wireless sensor networks, which can adaptively capture topological features to determine the reliability of target links, especially under the situations of routing table suffering from attack with varying degrees of damage to local link community. It is observed that, compared with other classical routing baselines, the proposed routing algorithm with link reliability prediction module can effectively improve the resilience of sensor networks while reserving high-energy-efficiency

The Transporter Classification Database: recent advances

The Transporter Classification Database (TCDB), freely accessible at http://www.tcdb.org, is a relational database containing sequence, structural, functional and evolutionary information about transport systems from a variety of living organisms, based on the International Union of Biochemistry and Molecular Biology-approved transporter classification (TC) system. It is a curated repository for factual information compiled largely from published references. It uses a functional/phylogenetic system of classification, and currently encompasses about 5000 representative transporters and putative transporters in more than 500 families. We here describe novel software designed to support and extend the usefulness of TCDB. Our recent efforts render it more user friendly, incorporate machine learning to input novel data in a semiautomatic fashion, and allow analyses that are more accurate and less time consuming. The availability of these tools has resulted in recognition of distant phylogenetic relationships and tremendous expansion of the information available to TCDB users