The cosmological constant as an eigenvalue of the Hamiltonian constraint in Horava-Lifshits theory

In the framework of Horava-Lifshitz theory, we study the eigenvalues associated with the Wheeler-DeWitt equation representing the vacuum expectation values associated with the cosmological constant. The explicit calculation is performed with the help of a variational procedure with trial wave functionals of the Gaussian type. We analyze both the case with the detailed balanced condition and the case without it. In the case without the detailed balance, we find the existence of an eigenvalue depending on the set of coupling constants (g2,g3) and (g4,g5,g6), respectively, and on the physical scale.Comment: RevTeX,11 Pages, Substantial Improvements. References added. To appear in Phys.Rev.

An Experimental Approach to Social Capital in South Africa

This paper measures the social capital of trust and trustworthiness in South Africa using an experimental protocol designed to distinguish these norms from altruism. Experimental participants played multiple roles, making it impossible to construct theoretically-grounded norm measures based on an individual's play across roles. Two-stage estimates of a social interaction model of norms identifies the presence of endogenous social effects, indicating that communities can be meaningfully typified as having and maintaining distinct normative environments. However, in contrast to studies that rely on less direct social capital measures, we do not find that trust boosts mean household living standards when controlling for the endogeneity of norms.

A Hamiltonian functional for the linearized Einstein vacuum field equations

By considering the Einstein vacuum field equations linearized about the Minkowski metric, the evolution equations for the gauge-invariant quantities characterizing the gravitational field are written in a Hamiltonian form by using a conserved functional as Hamiltonian; this Hamiltonian is not the analog of the energy of the field. A Poisson bracket between functionals of the field, compatible with the constraints satisfied by the field variables, is obtained. The generator of spatial translations associated with such bracket is also obtained.Comment: 5 pages, accepted in J. Phys.: Conf. Serie