Quantum Annealing in a Kinetically Constrained System

Classical and quantum annealing is discussed for a kinetically constrained chain of $N$ non-interacting asymmetric double wells, represented by Ising spins in a longitudinal field $h$. It is shown that in certain cases, where the kinetic constraints may arise from infinitely high but vanishingly narrow barriers appearing in the relaxation path of the system, quantum annealing exploiting the quantum-mechanical penetration of sufficiently narrow barriers may be far more efficient than its thermal counterpart. We have used a semiclassical picture of scattering dynamics to do our simulation for the quantum system.Comment: 5 pages, 3 figure

Composite Indices as International Approaches to Elderly Population Well-being Evaluation: Evidence from Russia

Population ageing is a natural process with irreversible consequences. Therefore, it has become an important agenda for economic and social policy. It requires the development and practical implementation of new tools for the integrated assessment of the main aspects of the elderly generation economic and social well-being. We account for over 50 years of active academic research work in the area of ​​enhanced elderly population’s well-being assessment as a complex socio-economic phenomenon. The phenomenon may comprise a number of components for evaluation on the basis of both quantitative objective criteria and qualitative subjective criteria. The paper addresses the question of using composite indices such as the AgeWatch Index and the Active Ageing Index for assessing the well-being of the elderly generation in the Russian Federation. The authors also debate the issue of the availability and comparability of the existing data for the Active Ageing Index calculation for Russia. The scope of the analysis falls within national Russian statistical databases in order to determine the possibility of the correct choice of relevant indicators from the sources available for the AAI calculation according to its original methodology

Noise induced rupture process: Phase boundary and scaling of waiting time distribution

A bundle of fibers has been considered here as a model for composite materials, where breaking of the fibers occur due to a combined influence of applied load (stress) and external noise. Through numerical simulation and a mean-field calculation we show that there exists a robust phase boundary between continuous (no waiting time) and intermittent fracturing regimes. In the intermittent regime, throughout the entire rupture process avalanches of different sizes are produced and there is a waiting time between two consecutive avalanches. The statistics of waiting times follows a Gamma distribution and the avalanche distribution shows power law scaling, similar to what have been observed in case of earthquake events and bursts in fracture experiments. We propose a prediction scheme that can tell when the system is expected to reach the continuous fracturing point from the intermittent phase.Comment: 6 pages, 8 figure

Model-based design of AM components to enable decentralized digital manufacturing systems

Additive manufacturing (AM) is a versatile technology that could add flexibility in manufacturing processes, whether implemented alone or along other technologies. This technology enables on-demand production and decentralized production networks, as production facilities can be located around the world to manufacture products closer to the final consumer (decentralized manufacturing). However, the wide adoption of additive manufacturing technologies is hindered by the lack of experience on its implementation, the lack of repeatability among different manufacturers and a lack of integrated production systems. The later, hinders the traceability and quality assurance of printed components and limits the understanding and data generation of the AM processes and parameters. In this article, a design strategy is proposed to integrate the different phases of the development process into a model-based design platform for decentralized manufacturing. This platform is aimed at facilitating data traceability and product repeatability among different AM machines. The strategy is illustrated with a case study where a car steering knuckle is manufactured in three different facilities in Sweden and Italy

Infinite-range Ising ferromagnet in a time-dependent transverse field: quench and ac dynamics near the quantum critical point

We study an infinite range ferromagnetic Ising model in the presence of a transverse magnetic field which exhibits a quantum paramagnetic-ferromagnetic phase transition at a critical value of the transverse field. In the thermodynamic limit, the low-temperature properties of this model are dominated by the behavior of a single large classical spin governed by an anisotropic Hamiltonian. Using this property, we study the quench and AC dynamics of the model both numerically and analytically, and develop a correspondence between the classical phase space dynamics of a single spin and the quantum dynamics of the infinite-range ferromagnetic Ising model. In particular, we compare the behavior of the equal-time order parameter correlation function both near to and away from the quantum critical point in the presence of a quench or AC transverse field. We explicitly demonstrate that a clear signature of the quantum critical point can be obtained by studying the AC dynamics of the system even in the classical limit. We discuss possible realizations of our model in experimental systems.Comment: Revtex4, 10 pages including 10 figures; corrected a sign error in Eq. 32; this is the final published versio

Mean field and Monte Carlo studies of the magnetization-reversal transition in the Ising model

Detailed mean field and Monte Carlo studies of the dynamic magnetization-reversal transition in the Ising model in its ordered phase under a competing external magnetic field of finite duration have been presented here. Approximate analytical treatment of the mean field equations of motion shows the existence of diverging length and time scales across this dynamic transition phase boundary. These are also supported by numerical solutions of the complete mean field equations of motion and the Monte Carlo study of the system evolving under Glauber dynamics in both two and three dimensions. Classical nucleation theory predicts different mechanisms of domain growth in two regimes marked by the strength of the external field, and the nature of the Monte Carlo phase boundary can be comprehended satisfactorily using the theory. The order of the transition changes from a continuous to a discontinuous one as one crosses over from coalescence regime (stronger field) to nucleation regime (weaker field). Finite size scaling theory can be applied in the coalescence regime, where the best fit estimates of the critical exponents are obtained for two and three dimensions.Comment: 16 pages latex, 13 ps figures, typos corrected, references adde

Griffiths-McCoy singularities in the transverse field Ising model on the randomly diluted square lattice

The site-diluted transverse field Ising model in two dimensions is studied with Quantum-Monte-Carlo simulations. Its phase diagram is determined in the transverse field (Gamma) and temperature (T) plane for various (fixed) concentrations (p). The nature of the quantum Griffiths phase at zero temperature is investigated by calculating the distribution of the local zero-frequency susceptibility. It is pointed out that the nature of the Griffiths phase is different for small and large Gamma.Comment: 21 LaTeX (JPSJ macros included), 12 eps-figures include

Quantum Annealing and Analog Quantum Computation

We review here the recent success in quantum annealing, i.e., optimization of the cost or energy functions of complex systems utilizing quantum fluctuations. The concept is introduced in successive steps through the studies of mapping of such computationally hard problems to the classical spin glass problems. The quantum spin glass problems arise with the introduction of quantum fluctuations, and the annealing behavior of the systems as these fluctuations are reduced slowly to zero. This provides a general framework for realizing analog quantum computation.Comment: 22 pages, 7 figs (color online); new References Added. Reviews of Modern Physics (in press

Incidence of human brucellosis in a rural area in Western Greece after the implementation of a vaccination programme against animal brucellosis

<p>Abstract</p> <p>Background</p> <p>Brucellosis continues to be an important source of morbidity in several countries, particularly among agricultural and pastoral populations. The purpose of this study was to examine if there is an effect on the incidence of human brucellosis after the implementation of an animal brucellosis control programme.</p> <p>Methods</p> <p>The study was conducted in the Municipality of Tritaia in the Prefecture of Achaia in Western Greece during the periods 1997–1998 and 2000–2002. Health education efforts were made during 1997–1998 to make the public take preventive measures. In the time period from January 1999 to August 2002 a vaccination programme against animal brucellosis was realised in the specific region. The vaccine used was the <it>B. melitensis </it>Rev-1 administered by the conjuctival route. Comparisons were performed between the incidence rates of the two studied periods.</p> <p>Results</p> <p>There was a great fall in the incidence rate between 1997–1998 (10.3 per 1,000 population) and the period 2000–2002 after the vaccination (0.3 per 1,000 population). The considerable decrease of the human incidence rate is also observed in the period 2000–2002 among persons whose herds were not as yet vaccinated (1.4 vs. 10.3 per 1,000 population), indicating a possible role of health education in the decline of human brucellosis.</p> <p>Conclusion</p> <p>The study reveals a statistically significant decline in the incidence of human brucellosis after the vaccination programme and underlines the importance of an ongoing control of animal brucellosis in the prevention of human brucellosis. The reduction of human brucellosis can be best achieved by a combination of health education and mass animal vaccination.</p