Local quantum measurement and no-signaling imply quantum correlations

We show that, assuming that quantum mechanics holds locally, the finite speed of information is the principle that limits all possible correlations between distant parties to be quantum mechanical as well. Local quantum mechanics means that a Hilbert space is assigned to each party, and then all local positive-operator-valued measurements are (in principle) available; however, the joint system is not necessarily described by a Hilbert space. In particular, we do not assume the tensor product formalism between the joint systems. Our result shows that if any experiment would give nonlocal correlations beyond quantum mechanics, quantum theory would be invalidated even locally.

Quantum simulations of classical annealing processes

We describe a quantum algorithm that solves combinatorial optimization problems by quantum simulation of a classical simulated annealing process. Our algorithm exploits quantum walks and the quantum Zeno effect induced by evolution randomization. It requires order 1/sqrt delta steps to find an optimal solution with bounded error probability, where delta is the minimum spectral gap of the stochastic matrices used in the classical annealing process. This is a quadratic improvement over the order 1/delta steps required by the latter.

Incentives and provider payment methods

The mode of payment creates powerful incentives affecting provider behavior and the efficiency, equity and quality outcomes of health finance reforms. This article examines provider incentives as well as administrative costs, and institutional conditions for successful implementation associated with provider payment alternatives. The alternatives considered are budget reforms, capitation, fee-for-service, and case-based reimbursement. We conclude that competition, whether through a regulated private sector or within a public system, has the potential to improve the performance of any payment method. All methods generate both adverse and beneficial incentives. Systems with mixed forms of provider payment can provide tradeoffs to offset the disadvantages of individual modes. Low-income countries should avoid complex payment systems requiring higher levels of institutional development.

Evaluating healthy days of life gained from health projects

This paper draws attention to the importance of incorporating weights for time preference and productivity in using the concept of healthy days of life lost to evaluate healthy projects. Two alternative health strategies are defined for Ghana and evaluated, over a range of discount rates from 0 to 20%, with regard to the present value of productive life saved. It is found that the relative ranking of the projects is sensitive to the choice of discount rates. The sensitivity of disease rankings to the underlying morbidity and fatality rates is also examined and the results underline the importance of obtaining better epidemiological baseline data and information on project effectiveness if the potential usefulness of the healthy days of life approach to project evaluation is to be fully realized.