Interplay between spin-density-wave and superconducting states in quasi-one-dimensional conductors

The interference between spin-density-wave and superconducting instabilities in quasi-one-dimensional correlated metals is analyzed using the renormalization group method. At the one-loop level, we show how the interference leads to a continuous crossover from a spin-density-wave state to unconventional superconductivity when deviations from perfect nesting of the Fermi surface exceed a critical value. Singlet pairing between electrons on neighboring stacks is found to be the most favorable symmetry for superconductivity. The consequences of non uniform spin-density-wave pairing on the structure of phase diagram within the crossover region is also discussed.Comment: 10 pages RevTex,4 Figures, submitted to EPJ

Immigration Reform and the Earnings of Latino Workers: Do Employer Sanctions Cause Discrimination?

This paper investigates whether employer sanctions for hiring undocumented workers introduced by the 1986 Immigration Reform and Control Act (IRCA) adversely affected the hourly earnings of Latino workers in the southwestern United States. We exploit the staggering of the sanctions and employee verification requirements across sectors to estimate this effect. In particular, IRCA’s employer-sanctions provisions were not extended to agricultural employers until 2 years after their imposition on nonagricultural employers. Hence, Latino agricultural workers provide a control group against which to compare changes in the wages of Latinos in nonagricultural employment. We find substantial pre-post IRCA declines in the hourly earnings of Latino nonagricultural workers relative to Latinos in agriculture. This pattern, however, is considerably stronger for Latino men than Latina women. We do not observe similar intersectoral shifts in relative wages among non-Latino white workers. In fact, the relative wage changes for non-Latino white workers are of the opposite sign. Finally, the pre-post IRCA relative decline in Latino nonagricultural wages reverses the pre-IRCA trend in which the relative earnings of Latino nonagricultural workers had been increasing.

Unbounded entropy in spacetimes with positive cosmological constant

In theories of gravity with a positive cosmological constant, we consider product solutions with flux, of the form (A)dS_p x S^q. Most solutions are shown to be perturbatively unstable, including all uncharged dS_p x S^q spacetimes. For dimensions greater than four, the stable class includes universes whose entropy exceeds that of de Sitter space, in violation of the conjectured "N-bound". Hence, if quantum gravity theories with finite-dimensional Hilbert space exist, the specification of a positive cosmological constant will not suffice to characterize the class of spacetimes they describe.Comment: 25 pages; v2: references adde

Making water policy and water laws democratic: lessons from South Indian states

The present attempt is to propose local people’s involvement in Water Policy and Water Law formulation in Indian sub continent on the growing realization that policies and laws the state governments have so far either visualized or implemented seems remain paper tigers. It examines the existing water laws and its implementation from 3 south Indian states viz., Kerala, Karnataka and Tamil Nadu for this purpose. Analysis shows that water laws mainly are centered on participatory irrigation management and water user associations. Groundwater laws are given lowest emphasis by the state governments where as majority of the Indian population depends upon it especially for domestic use. Indiscriminate sand mining is seen an emerging threat for river hydrological system that has accentuated by income tax rebates and gaps of housing policies. It indicates that the entire process of evolving water policy and laws is devoid of its stakeholders’ participation particularly from the grassroots level. Institutional framework to facilitate local people’s participation like Gram Sabha and Panchayati Raj Institutions are grossly underutilised for this purpose. On this background it examines the recent attempt of Kerala government in facilitating stakeholders’ participation in law formulation in water related Bill, called The Kerala Conservation of Paddy Fields and Wetlands Bill 2007.Length: pp.708-719Water policyWater lawLegislationStakeholders

Asymptotic Charges Cannot Be Measured in Finite Time

To study quantum gravity in asymptotically flat spacetimes, one would like to understand the algebra of observables at null infinity. Here we show that the Bondi mass cannot be observed in finite retarded time, and so is not contained in the algebra on any finite portion of ${\mathscr{I}}^+$. This follows immediately from recently discovered asymptotic entropy bounds. We verify this explicitly, and we find that attempts to measure a conserved charge at arbitrarily large radius in fixed retarded time are thwarted by quantum fluctuations. We comment on the implications of our results to flat space holography and the BMS charges at ${\mathscr{I}}^+$.Comment: 9 pages, 3 figures. v2 typos fixed and minor addition