Dual Poverty Trap: Intra- and Intergenerational Linkages in Frictional Labor Markets

This paper constructs an overlapping generations model with a frictional labor market to explain persistent low education in developing countries. When parents are uneducated, their children often face difficulties in finishing school and therefore are likely to remain uneducated. Moreover, if children expect that other children of the same generation will not receive an education, they expect that firms will not create enough jobs for educated workers, and thus are further discouraged from schooling. These intergenerational and intragenerational mechanisms reinforce each other, creating a serious poverty trap. Escape from the trap requires the well-organized and combined implementation of a subsidy for schooling, the provision of free education, support for disadvantaged children, and public awareness programs.overlapping generations model; education; poverty trap; job search; coordination failure

Spatially Modulated Vacua in a Lorentz-invariant Scalar Field Theory

Spatial modulation has been studied for a long time in condensed matter, nuclear matter and quark matter, so far in non-relativistic field theories. In this paper, spatially modulated vacua at zero temperature and zero density are studied in relativistic field theories. We first propose an adaptation of the Nambu-Goldstone theorem to higher derivative theories under the assumption of the absence of ghosts: when a global symmetry is spontaneously broken due to vacuum expectation values of space-time derivatives of fields, a Nambu-Goldstone (NG) boson appears without a canonical kinetic (quadratic derivative) term with a quartic derivative term in the modulated direction while a Higgs boson appears with a canonical kinetic term. We demonstrate this in a simple model allowing (meta)stable modulated vacuum of a phase modulation (Fulde-Ferrell state), where an NG mode associated with spontaneously broken translational and $U(1)$ symmetries appears.Comment: 20 pages, 3 figures, title changed, published versio