On the Electromagnetic Properties of Matter in Collapse Models

We discuss the electromagnetic properties of both a charged free particle, and a charged particle bounded by an harmonic potential, within collapse models. By choosing a particularly simple, yet physically relevant, collapse model, and under only the dipole approximation, we are able to solve the equation of motion exactly. In this way, both the finite time and large time behavior can be analyzed accurately. We discovered new features, which did not appear in previous works on the same subject. Since, so far, the spontaneous photon emission process places the strongest upper bounds on the collapse parameters, our results call for a further analysis of this process for those atomic systems which can be employed in experimental tests of collapse models, as well as of quantum mechanics.Comment: 17 pages, LaTeX, updated version with minor change

Towards Quantum Superpositions of a Mirror: an Exact Open Systems Analysis

We analyze the recently proposed mirror superposition experiment of Marshall, Simon, Penrose, and Bouwmeester, assuming that the mirror's dynamics contains a non-unitary term of the Lindblad type proportional to -[q,[q,\rho]], with q the position operator for the center of mass of the mirror, and \rho the statistical operator. We derive an exact formula for the fringe visibility for this system. We discuss the consequences of our result for tests of environmental decoherence and of collapse models. In particular, we find that with the conventional parameters for the CSL model of state vector collapse, maintenance of coherence is expected to within an accuracy of at least 1 part in 10^{8}. Increasing the apparatus coupling to environmental decoherence may lead to observable modifications of the fringe visibility, with time dependence given by our exact result.Comment: 4 pages, RevTeX. Substantial changes mad

Reverse Innovation: An Opportunity for Strengthening Health Systems

BACKGROUND: Canada, when compared to other OECD countries, ranks poorly with respect to innovation and innovation adoption while struggling with increasing health system costs. As a result of its failure to innovate, the Canadian health system will struggle to meet the needs and demands of both current and future populations. The purpose of this initiative was to explore if a competition-based reverse innovation challenge could mobilize and stimulate current and future leaders to identify and lead potential reverse innovation projects that address health system challenges in Canada. METHODS: An open call for applications took place over a 4-month period. Applicants were enticed to submit to the competition with a $50,000 prize for the top submission to finance their project. Leaders from a wide cross-section of sectors collectively developed evaluation criteria and graded the submissions. The criteria evaluated: proof of concept, potential value, financial impact, feasibility, and scalability as well as the use of prize money and innovation team. RESULTS: The competition received 12 submissions from across Canada that identified potential reverse innovations from 18 unique geographical locations that were considered developing and/or emerging markets. The various submissions addressed health system challenges relating to education, mobile health, aboriginal health, immigrant health, seniors health and women\u27s health and wellness. Of the original 12 submissions, 5 finalists were chosen and publically profiled, and 1 was chosen to receive the top prize. CONCLUSIONS: The results of this initiative demonstrate that a competition that is targeted to reverse innovation does have the potential to mobilize and stimulate leaders to identify reverse innovations that have the potential for system level impact. The competition also provided important insights into the capacity of Canadian students, health care providers, entrepreneurs, and innovators to propose and implement reverse innovation in the context of the Canadian health system

Simulation and analysis of solenoidal ion sources

We present a detailed analysis and simulation of solenoidal, magnetically confined electron bombardment ion sources, aimed at molecular beam detection. The aim is to achieve high efficiency for singly ionized species while minimizing multiple ionization. Electron space charge plays a major role and we apply combined ray tracing and finite element simulations to determine the properties of a realistic geometry. The factors controlling electron injection and ion extraction are discussed. The results from simulations are benchmarked against experimental measurements on a prototype source

A window to quantum gravity phenomena in the emergence of the seeds of cosmic structure

Inflationary cosmology has, in the last few years,received a strong dose of support from observations. The fact that the fluctuation spectrum can be extracted from the inflationary scenario through an analysis that involves quantum field theory in curved space-time, and that it coincides with the observational data has lead to a certain complacency in the community, which prevents the critical analysis of the obscure spots in the derivation. We argue here briefly, as we have discussed in more detail elsewhere, that there is something important missing in our understanding of the origin of the seeds of Cosmic Structure, as is evidenced by the fact that in the standard accounts the inhomogeneity and anisotropy of our universe seems to emerge from an exactly homogeneous andisotropic initial state through processes that do not break those symmetries. This article gives a very brief recount of the problems faced by the arguments based on established physics. The conclusion is that we need some new physics to be able to fully address the problem. The article then exposes one avenue that has been used to address the central issue and elaborates on the degree to which, the new approach makes different predictions from the standard analyses. The approach is inspired on Penrose's proposals that Quantum Gravity might lead to a real, dynamical collapse of the wave function, a process that we argued has the properties needed to extract us from the theoretical impasse described above.Comment: 13 pages, 3 figures. To appear in DICE 2008 conference proceeding

On the scaling of entropy viscosity in high order methods

In this work, we outline the entropy viscosity method and discuss how the choice of scaling influences the size of viscosity for a simple shock problem. We present examples to illustrate the performance of the entropy viscosity method under two distinct scalings

Purifying and Reversible Physical Processes

Starting from the observation that reversible processes cannot increase the purity of any input state, we study deterministic physical processes, which map a set of states to a set of pure states. Such a process must map any state to the same pure output, if purity is demanded for the input set of all states. But otherwise, when the input set is restricted, it is possible to find non-trivial purifying processes. For the most restricted case of only two input states, we completely characterize the output of any such map. We furthermore consider maps, which combine the property of purity and reversibility on a set of states, and we derive necessary and sufficient conditions on sets, which permit such processes.Comment: 5 pages, no figures, v2: only minimal change