Nonequilibrium Steady State Driven by a Nonlinear Drift Force

We investigate the properties of the nonequilibrium steady state for the stochastic system driven by a nonlinear drift force and influenced by noises which are not identically and independently distributed. The nonequilibrium steady state (NESS) current results from a residual part of the drift force which is not cancelled by the diffusive action of noises. From our previous study for the linear drift force the NESS current was found to circulate on the equiprobability surface with the maximum at a stable fixed point of the drift force. For the nonlinear drift force, we use the perturbation theory with respect to the cubic and quartic coefficients of the drift force. We find an interesting potential landscape picture where the probability maximum shifts from the fixed point of the drift force and, furthermore, the NESS current has a nontrivial circulation which flows off the equiprobability surface and has various centers not located at the probability maximum. The theoretical result is well confirmed by the computer simulation.Comment: 10 pages, 4 figure

Extracting and Stabilizing the Unstable State of Hysteresis Loop

A novel perturbation method for the stabilization of unstable intermediate states of hysteresis loop (i.e. S-shaped curve) is proposed. This method only needs output signals of the system to construct the perturbation form without delay-coordinate embedding technique, it is more practical for real-world systems. Stabilizing and tracking the unstable intermediate branch are demonstrated through the examples of a bistable laser system and delay feedback system. All the numerical results are obtained by simulating each of the real experimential conditions.Comment: 6 pages, REVTEX, 4 ps figure

Generating entanglement between microwave photons and qubits in multiple cavities coupled by a superconducting qutrit

We discuss how to generate entangled coherent states of four \textrm{microwave} resonators \textrm{(a.k.a. cavities)} coupled by a superconducting qubit. We also show \textrm{that} a GHZ state of four superconducting qubits embedded in four different resonators \textrm{can be created with this scheme}. In principle, \textrm{the proposed method} can be extended to create an entangled coherent state of $n$ resonators and to prepare a Greenberger-Horne-Zeilinger (GHZ) state of $n$ qubits distributed over $n$ cavities in a quantum network. In addition, it is noted that four resonators coupled by a coupler qubit may be used as a basic circuit block to build a two-dimensional quantum network, which is useful for scalable quantum information processing.Comment: 13 pages, 7 figure

A novel implementation of method of optimality criterion in synthesizing spacecraft structures with natural frequency constraints

In the design of spacecraft structures, fine tuning the structure to achieve minimum weight with natural frequency constraints is a time consuming process. Here, a novel implementation of the method of optimality criterion (OC) is developed. In this new implementation of OC, the free vibration analysis results are used to compute the eigenvalue sensitivity data required for the formulation. Specifically, the modal elemental strain and kinetic energies are used. Additionally, normalized design parameters are introduced as a second level linking that allows design variables of different values to be linked together. With the use of this novel formulation, synthesis of structures with natural frequency constraint can be carried out manually using modal analysis results. Design examples are presented to illustrate this novel implementation of the optimality criterion method

Aharonov-Bohm oscillations in the local density of topological surface states

We study Aharonov-Bohm (AB) oscillations in the local density of states (LDOS) for topological insulator (TI) and conventional metal Au(111) surfaces with spin-orbit interaction, which can be probed by spin-polarized scanning tunneling microscopy. We show that the spacial AB oscillatory period in the total LDOS is a flux quantum $\Phi_{0}\mathtt{=}hc/e$ (weak localization) in both systems. Remarkably, an analogous weak antilocalization with $\Phi_{0}/2$ periodic spacial AB oscillations in spin components of LDOS for TI surface is observed, while it is absent in Au(111).Comment: 4 APL pages, 3 figure

Generating distributed entanglement from electron currents

This work is partially supported by a Royal Society University Research FellowshipSeveral recent experiments have demonstrated the viability of a passive device that can generate spin-entangled currents in two separate leads. However, manipulation and measurement of individual flying qubits in a solid state system has yet to be achieved. This is particularly difficult when a macroscopic number of these indistinguishable qubits are present. In order to access such an entangled current resource, we therefore show how to use it to generate distributed, static entanglement. The spatial separation between the entangled static pair can be much higher than that achieved by only exploiting the tunnelling effects between quantum dots. Our device is completely passive, and requires only weak Coulomb interactions between static and flying spins. We show that the entanglement generated is robust to decoherence for large enough currents.Publisher PDFPeer reviewe

Endocidal Regulation of Secondary Metabolites in the Producing Organisms

Secondary metabolites are defined as organic compounds that are not directly involved in the normal growth, development, and reproduction of an organism. They are widely believed to be responsible for interactions between the producing organism and its environment, with the producer avoiding their toxicities. In our experiments, however, none of the randomly selected 44 species representing different groups of plants and insects can avoid autotoxicity by its endogenous metabolites once made available. We coined the term endocides (endogenous biocides) to describe such metabolites that can poison or inhibit the parent via induced biosynthesis or external applications. Dosage-dependent endocides can selectively induce morphological mutations in the parent organism (e.g., shrubbiness/dwarfism, pleiocotyly, abnormal leaf morphogenesis, disturbed phyllotaxis, fasciated stems, and variegation in plants), inhibit its growth, development, and reproduction and cause death than non-closely related species. The propagule, as well as the organism itself contains or produces adequate endocides to kill itself

High inflation: causes and consequences

Using evidence from seven hyperinflationary episodes in four Latin American countries in the second half of the 1980s, John Rogers and Ping Wang examine the causes and consequences of high inflation. The article emphasizes four issues: the welfare costs of inflation and real costs of stabilization, the common features of the chronically high inflations experienced in Latin American countries, the main causes of high inflation, and the widely different outcomes of several stabilization programs. ; Rogers and Wang find that the welfare costs of even moderate periods of inflation may not be negligible, whereas the adverse macroeconomic effects of stabilization efforts are mostly temporary. The authors show that the spiral-like adjustment of the government budget and monetary growth may result in a high-inflation trap. The main causes of chronically high inflation include continuous fiscal-monetary extension, productivity slowdown, systematic undervaluation of the domestic currency, and diminished credibility of anti-inflation policies. Successful stabilization, in essence, results from budgetary adjustment, market liberalization, and the adoption of a nominal anchor (such as the nominal exchange rate), all of which ensure credibility of the public authorities.Inflation (Finance)