Highly Accurate Electronic Structure of Metallic Solids from Coupled-Cluster Theory with Nonperturbative Triple Excitations.

Coupled-cluster theory with single, double, and perturbative triple excitations (CCSD(T))-often considered the "gold standard" of main-group quantum chemistry-is inapplicable to three-dimensional metals due to an infrared divergence, preventing its application to many important problems in materials science. We study the full, nonperturbative inclusion of triple excitations (CCSDT) and propose a new, iterative method, which we call ring-CCSDT, that resums the essential triple excitations with the same N^{7} run-time scaling as CCSD(T). CCSDT and ring-CCSDT are used to calculate the correlation energy of the uniform electron gas at metallic densities and the structural properties of solid lithium.

Accurate Quantum Chemical Reaction Energies for Lithium-Mediated Electrolyte Decomposition and Evaluation of Density Functional Approximations.

An important concern related to the performance of Li-ion batteries is the formation of a solid electrolyte interphase on the surface of the anode. This film is formed from the decomposition of electrolytes and can have important effects on the stability and performance. Here, we evaluate the decomposition pathway of ethylene carbonate and related organic electrolyte molecules using a series of density functional approximations and correlated wave function (WF) methods, including the coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)] and auxiliary-field quantum Monte Carlo (AFQMC).

Ground-State Properties of Metallic Solids from Ab Initio Coupled-Cluster Theory.

Metallic solids are an enormously important class of materials, but they are a challenging target for accurate wave function-based electronic structure theories and have not been studied in great detail by such methods. Here, we use coupled-cluster theory with single and double excitations (CCSD) to study the structure of solid lithium and aluminum using optimized Gaussian basis sets. We calculate the equilibrium lattice constant, bulk modulus, and cohesive energy and compare them to experimental values, finding accuracy comparable to common density functionals.

Making the most of data: Quantum Monte Carlo postanalysis revisited.

In quantum Monte Carlo (QMC) methods, energy estimators are calculated as (functions of) statistical averages of quantities sampled during a calculation. Associated statistical errors of these averages are often estimated. This error estimation is not straightforward and there are several choices of the error estimation methods.

Are we there yet? Principles in advancing equity though global public health research.

Canadian engagement in global and public health includes a long history of centering issues of equity in practice, policy, and research. In 2015, through a series of deliberative dialogues about what ethical standards should guide how people engage in global health research, the Canadian Coalition for Global Health Research (CCGHR) released a set of six equity-centred principles and critically reflective questions. These principles offered a platform for identifying equity implications and choices about theories, methods, approaches, partnerships, or practices in global and public health.

Accelerating Convergence in Fock Space Quantum Monte Carlo Methods.

The convergence of full configuration interaction quantum Monte Carlo (FCIQMC) is accelerated using a quasi-Newton propagation (QN) which can also be applied to coupled cluster Monte Carlo (CCMC). The computational scaling of this optimized propagation is [Formula: see text], keeping the additional computational cost to a bare minimum. Its effects are investigated deterministically and stochastically on a model system, the uniform electron gas, with Hilbert space size up to 10, and shown to accelerate convergence of the instantaneous projected energy by over an order of magnitude in the FCIQMC test case.

The HANDE-QMC Project: Open-Source Stochastic Quantum Chemistry from the Ground State Up.

Building on the success of Quantum Monte Carlo techniques such as diffusion Monte Carlo, alternative stochastic approaches to solve electronic structure problems have emerged over the past decade. The full configuration interaction quantum Monte Carlo (FCIQMC) method allows one to systematically approach the exact solution of such problems, for cases where very high accuracy is desired. The introduction of FCIQMC has subsequently led to the development of coupled cluster Monte Carlo (CCMC) and density matrix quantum Monte Carlo (DMQMC), allowing stochastic sampling of the coupled cluster wave function and the exact thermal density matrix, respectively.

Large scale parallelization in stochastic coupled cluster.

Coupled cluster theory is a vital cornerstone of electronic structure theory and is being applied to ever-larger systems. Stochastic approaches to quantum chemistry have grown in importance and offer compelling advantages over traditional deterministic algorithms in terms of computational demands, theoretical flexibility, or lower scaling with system size. We present a highly parallelizable algorithm of the coupled cluster Monte Carlo method involving sampling of clusters of excitors over multiple time steps.

Exciting Determinants in Quantum Monte Carlo: Loading the Dice with Fast, Low-Memory Weights.

High-quality excitation generators are crucial to the effectiveness of coupled cluster Monte Carlo (CCMC) and full configuration interaction Quantum Monte Carlo (FCIQMC) calculations. The heat bath sampling of Holmes et al. [Holmes, A.

Facing a Paradigm Shift in the Sustainable Development Goal Era.

The Sustainable Development Goals challenge us to step beyond traditional development approaches and to consider strategies that are evidence informed and innovative. The concepts are familiar; themes aligned with Harmonization, Primary Healthcare, Leadership, Public Private Partnerships, Community Engagement, and Integrated Technologies. However, to optimize resources and overcome today's challenge with sustainable solutions, we must capture lessons learned and apply evidence developed to inform and expand the thinking to shape and inform new paradigms.

A study of the dense uniform electron gas with high orders of coupled cluster.

We investigate the accuracies of different coupled cluster levels in a finite model solid, the 14 electron spin-non-polarised uniform electron gas. For densities between r = 0.5 a and r = 5 a, we calculate ground state correlation energies with stochastic coupled cluster ranging from coupled cluster singles and doubles (CCSD) to coupled cluster including all excitations up to quintuples (CCSDTQ5).

Measurement of the two-photon exchange contribution to the elastic e(±)p scattering cross sections at the VEPP-3 storage ring.

The ratio of the elastic e(+)p to e(-)p scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.

Making a commitment to ethics in global health research partnerships: a practical tool to support ethical practice.

Global health research partnerships have many benefits, including the development of research capacity and improving the production and use of evidence to improve global health equity. These partnerships also include many challenges, with power and resource differences often leading to inequitable and unethical partnership dynamics. Responding to these challenges and to important gaps in partnership scholarship, the Canadian Coalition for Global Health Research (CCGHR) conducted a three-year, multi-regional consultation to capture the research partnership experiences of stakeholders in South Asia, Latin America, and sub-Saharan Africa.

Mentoring, training and support to global health innovators: a scoping review.

Global health innovators must navigate substantial complexities to successfully develop, implement and sustain global health innovations with impact through application of an Integrated InnovationTM approach. We sought to examine the nature of the literature and evidence around mentoring, training and support of global health innovators. We conducted a scoping review searching eight databases with terms capturing different kinds of innovation and support.

Funding agencies in low- and middle-income countries: support for knowledge translation.

Objective: The aim was to describe how selected health research funding agencies active in low- and middle-income countries promote the translation of their funded research into policy and practice.

Methods: We conducted inductive analysis of semi-structured interviews with key informants from a purposive sample of 23 national and international funding agencies that fund health research in Brazil, Colombia, India, the Philippines, South Africa and Thailand. We also surveyed web sites.

Creating and testing the concept of an academic NGO for enhancing health equity: a new mode of knowledge production?

Context: Collaborative action is required to address persistent and systematic health inequities which exist for most diseases in most countries of the world.

Objectives: The Academic NGO initiative (ACANGO) described in this paper was set up as a focused network giving priority to twinned partnerships between Academic research centres and community-based NGOs. ACANGO aims to capture the strengths of both in order to build consensus among stakeholders, engage the community, focus on leadership training, shared management and resource development and deployment.

Health implications of small arms and light weapons in eastern Uganda.

Injuries due to small arms and light weapons (SALW) are common in developing countries with ongoing collective violence, or those that exist in a post-conflict state. Uganda has a long history of armed conflict, but little quantitative evidence is available about the extent of the problem of SALW. We performed a review of all injuries due to SALW at Mbale Regional Hospital in eastern Uganda for the six-year period 1998-2003.

Health Research Profile to assess the capacity of low and middle income countries for equity-oriented research.

Background: The Commission on Health Research for Development concluded that "for the most vulnerable people, the benefits of research offer a potential for change that has gone largely untapped." This project was designed to assess low and middle income country capacity and commitment for equity-oriented research.

Methods: A multi-disciplinary team with coordinators from each of four regions (Asia, Latin America, Africa and Central and Eastern Europe) developed a questionnaire through consensus meetings using a mini-Delphi technique.

Canada and global health research: 2005 update.

From a global perspective, large disparities persist between the focus of health research investments and the global burden of illness. Over the past four years, Canadian efforts to address these disparities have steadily increased. The objectives of this paper are to present these recent achievements and to highlight continuing challenges.