Convergence of Quantum Annealing with Real-Time Schrodinger Dynamics

Convergence conditions for quantum annealing are derived for optimization problems represented by the Ising model of a general form. Quantum fluctuations are introduced as a transverse field and/or transverse ferromagnetic interactions, and the time evolution follows the real-time Schrodinger equation. It is shown that the system stays arbitrarily close to the instantaneous ground state, finally reaching the target optimal state, if the strength of quantum fluctuations decreases sufficiently slowly, in particular inversely proportionally to the power of time in the asymptotic region. This is the same condition as the other implementations of quantum annealing, quantum Monte Carlo and Green's function Monte Carlo simulations, in spite of the essential difference in the type of dynamics. The method of analysis is an application of the adiabatic theorem in conjunction with an estimate of a lower bound of the energy gap based on the recently proposed idea of Somma et. al. for the analysis of classical simulated annealing using a classical-quantum correspondence.Comment: 6 pages, minor correction

Convergence theorems for quantum annealing

We prove several theorems to give sufficient conditions for convergence of quantum annealing, which is a protocol to solve generic optimization problems by quantum dynamics. In particular the property of strong ergodicity is proved for the path-integral Monte Carlo implementation of quantum annealing for the transverse Ising model under a power decay of the transverse field. This result is to be compared with the much slower inverse-log decay of temperature in the conventional simulated annealing. Similar results are proved for the Green's function Monte Carlo approach. Optimization problems in continuous space of particle configurations are also discussed.Comment: 19 page

Kink pairs unbinding on domain walls and the sequence of phase transitions in fully frustrated XY models

The unbinding of kink pairs on domain walls in the fully frustrated XY model (on square or triangular lattices) is shown to induce the vanishing of phase coupling across the walls. This forces the phase transition, associated with unbinding of vortex pairs to take place at a lower temperature than the other phase transition, associated with proliferation of the Ising-type domain walls. The results are applicable for a description of superconducting junction arrays and wire networks in perpendicular magnetic field (corresponding to half-integer number of flux quanta per each lattice plaquette), as well as of planar antiferromagnets with a triangular lattice.Comment: 4 pages, ReVTeX, the final versio

An ALMA Search for Substructure, Fragmentation, and Hidden Protostars in Starless Cores in Chamaeleon I

We present an Atacama Large Millimeter/submillimeter Array (ALMA) 106 GHz (Band 3) continuum survey of the complete population of dense cores in the Chamaeleon I molecular cloud. We detect a total of 24 continuum sources in 19 different target fields. All previously known Class 0 and Class I protostars in Chamaeleon I are detected, whereas all of the 56 starless cores in our sample are undetected. We show that the Spitzer+Herschel census of protostars in Chamaeleon I is complete, with the rate at which protostellar cores have been misclassified as starless cores calculated as <1/56, or < 2%. We use synthetic observations to show that starless cores collapsing following the turbulent fragmentation scenario are detectable by our ALMA observations when their central densities exceed ~10^8 cm^-3, with the exact density dependent on the viewing geometry. Bonnor-Ebert spheres, on the other hand, remain undetected to central densities at least as high as 10^10 cm^-3. Our starless core non-detections are used to infer that either the star formation rate is declining in Chamaeleon I and most of the starless cores are not collapsing, matching the findings of previous studies, or that the evolution of starless cores are more accurately described by models that develop less substructure than predicted by the turbulent fragmentation scenario, such as Bonnor-Ebert spheres. We outline future work necessary to distinguish between these two possibilities.Comment: Accepted by Ap

Properties of M31. II: A Cepheid disk sample derived from the first year of PS1 PAndromeda data

We present a sample of Cepheid variable stars towards M31 based on the first year of regular M31 observations of the PS1 survey in the r_P1 and i_P1 filters. We describe the selection procedure for Cepheid variable stars from the overall variable source sample and develop an automatic classification scheme using Fourier decomposition and the location of the instability strip. We find 1440 fundamental mode (classical \delta) Cep stars, 126 Cepheids in the first overtone mode, and 147 belonging to the Population II types. 296 Cepheids could not be assigned to one of these classes and 354 Cepheids were found in other surveys. These 2009 Cepheids constitute the largest Cepheid sample in M31 known so far and the full catalog is presented in this paper. We briefly describe the properties of our sample in its spatial distribution throughout the M31 galaxy, in its age properties, and we derive an apparent period-luminosity relation (PLR) in our two bands. The Population I Cepheids nicely follow the dust pattern of the M31 disk, whereas the 147 Type II Cepheids are distributed throughout the halo of M31. We outline the time evolution of the star formation in the major ring found previously and find an age gradient. A comparison of our PLR to previous results indicates a curvature term in the PLR

Designing Shared Decision-Making Interventions for Dissemination and Sustainment: Can Implementation Science Help Translate Shared Decision Making Into Routine Practice

Shared decision making (SDM) is not widely practiced in routine care due to a variety of organizational, provider, patient, and contextual factors. This article explores how implementation science-which encourages attention to the multilevel contextual factors that influence the adoption, implementation, and sustainment of health care practices-can provide useful insights for increasing SDM use in routine practice. We engaged with stakeholders representing different organizations and geographic locations over three phases: 1) multidisciplinary workgroup meeting comprising researchers and clinicians (n = 11); 2) survey among a purposive sample of 47 patient advocates, clinicians, health care system leaders, funders, policymakers, and researchers; and 3) working session among diverse stakeholders (n = 30). The workgroup meeting identified priorities for action and research, which included targeting multiple audiences and levels, shifting culture toward valuing and supporting SDM, and considering contextual factors influencing SDM implementation. Survey respondents provided recommendations for increasing adoption, implementation, and maintenance of SDM in practice including providing tools to support SDM, obtaining stakeholders\u27 involvement, and raising awareness of the importance of SDM. Stakeholders in the working session provided recommendations on the design of a guide for implementation of SDM in clinical settings, strategies to disseminate educational curricula on SDM, and strategies to influence policies to increase SDM use. These specific recommendations serve as a call to action to pursuing specific promising strategies aimed at increasing SDM use in practice and enhance understanding of the perspectives of diverse stakeholders at multiple levels from an implementation science perspective that appear fruitful for further study and application

Decreased dyskerin levels as a mechanism of telomere shortening in X-linked dyskeratosis congenita

Dyskeratosis congenita (DC) is a premature ageing syndrome characterised by short telomeres. An X-linked form of DC is caused by mutations in DKC1 which encodes dyskerin, a telomerase component that is essential for telomerase RNA stability. However, mutations in DKC1 are identifiable in only half of X-linked DC families. A four generation family with pulmonary fibrosis and features of DC was identified. Affected males showed the classic mucocutaneous features of DC and died prematurely from pulmonary fibrosis. Although there were no coding sequence or splicing variants, genome wide linkage analysis of 16 individuals across four generations identified significant linkage at the DKC1 locus, and was accompanied by reduced dyskerin protein levels in affected males. Decreased dyskerin levels were associated with compromised telomerase RNA levels and very short telomeres. These data identify decreased dyskerin levels as a novel mechanism of DC, and indicate that intact dyskerin levels, in the absence of coding mutations, are critical for telomerase RNA stability and for in vivo telomere maintenance

Trust and Credibility in Web-Based Health Information: A Review and Agenda for Future Research

Background: Online sources are becoming increasingly important in health information seeking, such that they may have a significant effect on health care decisions and outcomes. Hence, given the wide range of different sources of online health information from different organisations and individuals, it is important to understand how information seekers evaluate and select the sources that they use, and, more specifically how they assess their credibility and trustworthiness. Objectives: This article reviews empirical studies on trust and credibility in the use of online health information. The article seeks to present a profile of the research conducted on trust and credibility in online health information seeking, to identify the factors that impact judgements of trustworthiness and credibility, and to explore the role of demographic factors affecting trust formation. On this basis, it aims to identify the gaps in current knowledge and to propose an agenda for future research. Methods: A systematic literature review was conducted. Searches were conducted using a variety of combinations of the terms: online health information, trust, credibility, and their variants, in four multi-disciplinary and four health-oriented databases. Articles selected were published in English from 2000 onwards; this process generated 3827 unique records. After the application of exclusion criteria, this was reduced to a final dataset of 73 articles, which was analysed in full. Results: Interest in this topic has persisted over the last 15 years, with articles being published in medicine, social science and computer science, and focussing mostly on the USA and the UK. Documents in the dataset fell into three categories: those using trust or credibility as a dependent variable, those using trust or credibility as an independent variable, and studies of the demographic factors that influence the role of trust or credibility in online health information seeking. There is a consensus that in terms of website design, clear layout and design, interactive features and the authority of the owner have a positive effect on trust or credibility, whilst advertising has a negative effect. With regard to content features, authority of the author, ease of use and content have a positive effect on trust or credibility formation. Demographic factors influencing trust formation are age, gender and perceived health status. Conclusions: There is considerable scope for further research. This includes: increased clarity of the interaction between the variables associated with health information seeking; increased consistency on the measurement of trust and credibility; a greater focus on specific online health information sources; and, enhanced understanding of the impact of demographic variables on trust and credibility judgement

Evidence for Supernova Signatures in the Spectrum of the Late-time Bump of the Optical Afterglow of GRB 021211

We present photometric and spectroscopic observations of the gamma-ray burst GRB 021211 obtained during the late stages of its afterglow. The light curve shows a rebrightening occurring ~25 days after the GRB. The analysis of a VLT spectrum obtained during the bump (27 days after the GRB) reveals a suggestive resemblance with the spectrum of the prototypical type-Ic SN 1994I, obtained about ~10 days past maximum light. Particularly we have measured a strong, broad absorption feature at 3770 A, which we have identified with Ca II blueshifted by ~14400 km/s, thus indicating that a supernova (SN) component is indeed powering the `bump' in the afterglow decay. Assuming SN 1994I as a template, the spectroscopic and photometric data together indicate that the SN and GRB explosions were at most separated by a few days. Our results suggest that GRBs might be associated also to standard type-Ic supernovae.Comment: 6 pages, 4 color figures. Accepted for publication in A&A Letters. Fig. 4 does not appair in the A&A version due to space restrictions. Includes aa.cls and txfonts.st

The one-dimensional contact process: duality and renormalisation

We study the one-dimensional contact process in its quantum version using a recently proposed real space renormalisation technique for stochastic many-particle systems. Exploiting the duality and other properties of the model, we can apply the method for cells with up to 37 sites. After suitable extrapolation, we obtain exponent estimates which are comparable in accuracy with the best known in the literature.Comment: 15 page