Theory of I-V Characteristics of Magnetic Josephson Junctions

We analyze the electrical characteristics of a circuit consisting of a free thin-film magnetic layer and source and drain electrodes that have opposite magnetization orientations along the free magnet's two hard directions. We find that when the circuit's current exceeds a critical value there is a sudden resistance increase which can be large in relative terms if the currents to source or drain are strongly spin polarized and the free magnet is thin. This behavior can be partly understood in terms of a close analogy between the magnetic circuit and a Josephson junction

An SCO-enabled logistics and supply-chain management system in construction

Logistic and supply chain management (LSCM) is of paramount importance to a construction project but is often problematic. Many researchers see LSCM per se as a web of decisions to be made, and attribute problems to a lack of process and information concurrence. This is exacerbated by fragmentation, discontinuity, and heterogeneity in construction LSCM. The bi-directional information flow remains unachieved in the existing sensing-based systems for construction LSCM. Without panoramically interconnected to other smart abilities such as the automatic action-taking ability, most existing sensing-based systems are insufficient to realize their full potentials in facilitating construction LSCM. Building on previous studies on smart construction objects (SCOs), this paper aims to develop an SCO-enabled system that can enhance concurrence of process and information, with a view to informing better decision-making in construction LSCM. It does so by first analyzing the problems in prevailing LSCM practices using business process reengineering. Based on this analysis, the architecture for an SCO-enabled LSCM system is proposed and developed into a prototype. Then the system is calibrated and validated in the rich context of offshore prefabrication housing production in Hong Kong. It is found that SCOs, with their properties of awareness, communicativeness, and autonomy built into a smart management system, can supplement the existing LSCM process with more concurrent decision-making information. This paper contributes to the body of knowledge in two areas. It adds to the theoretical debate on decision-making by arguing the importance of information and process concurrence and trying to explicate it in the context of construction LSCM. In addition, the SCO-enabled LSCM system can be implemented in real-life practice to alleviate the many problems existing in construction LSCM.postprin

Disappearance of integer quantum Hall effect

The disappearance of integer quantum Hall effect (IQHE) at strong disorder and weak magnetic field is studied in a lattice model. A generic sequence by which the IQHE plateaus disappear is revealed: higher IQHE plateaus always vanish earlier than lower ones, and extended levels between those plateaus do not float up in energy but keep merging together after the destruction of plateaus. All of these features remain to be true in the weak-field limit as shown by the thermodynamic-localization-length calculation. Topological characterization in terms of Chern integers provides a simple physical explanation and suggests a qualitative difference between the lattice and continuum models.Comment: Revtex, four pages; four figures, postscript fil

Precision of Quantization of the Hall Conductivity in a Sample of Finite Size: Power Law

A microscopic calculation of the conductivity in the integer quantum Hall effect (IQHE) regime is carried out. The problem of precision of quantization is analyzed for samples of finite size. It is demonstrated that the precision of quantization shows a power-law dependence on the sample size. A new scaling parameter describing a dependence of this kind is introduced. It is also demonstrated that the precision of quantization linearly depends on the ratio between the amplitude of the chaotic potential and the cyclotron energy. The results obtained are compared with the magnetotransport measurements in mesoscopic samples.Comment: 5 pages, 4 figure

Quantum cloning and the capacity of the Pauli channel

A family of quantum cloning machines is introduced that produce two approximate copies from a single quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, describing the balance between the quality of the two copies. This also provides an upper bound on the quantum capacity of the Pauli channel with probabilities $p_x$, $p_y$ and $p_z$. The capacity is shown to be vanishing if $(\sqrt{p_x},\sqrt{p_y},\sqrt{p_z})$ lies outside an ellipsoid whose pole coincides with the depolarizing channel that underlies the universal cloning machine.Comment: 5 pages RevTeX, 3 Postscript figure

Palaeopathology in a Cretaceous terrestrial lizard from China

The lizard genus Yabeinosaurus is a common and relatively well-known member of Chinese Lower Cretaceous Jehol Biota, found in both the Yixian and Jiufotang formations of north-eastern China. Previous research on Yabeinosaurus has revealed information on its morphology, phylogenetic position, colouration, diet, and viviparous reproductive strategy. Herein we describe a new specimen preserving the skull and postcranial skeleton. The skull shows features characteristic of Yabeinosaurus robustus, but reveals the morphology of the vomer for the first time. In the postcranial skeleton, the most significant feature is a malformation of the fibula resulting from a fracture that occurred several months before the animal died, possibly as the result of intraspecies aggression or a predation attempt

Control of atomic currents using a quantum stirring device

We propose a BEC stirring device which can be regarded as the incorporation of a quantum pump into a closed circuit: it produces a DC circulating current in response to a cyclic adiabatic change of two control parameters of an optical trap. We demonstrate the feasibility of this concept and point out that such device can be utilized in order to probe the interatomic interactions.Comment: 5 pages, 4 figures, uses epl2.cls, revised versio