No abstract

Thermal corrections to Schwinger pair production are potentially important in particle physics, nuclear physics and cosmology. However, the lowest-order contribution, arising at one loop, has proved difficult to calculate unambiguously. We show that this thermal correction may be calculated for charged scalars using the worldline formalism, where each term in the decay rate is associated with a worldline instanton. We calculate all finite-temperature worldline instantons, their actions and fluctuations prefactors, thus determining the complete one-loop decay rate at finite temperature. The thermal contribution to the decay rate becomes nonzero at a threshold temperature T = eE/2m, above which it dominates the zero temperature result. This is the lowest of an infinite set of thresholds at T = neE/2m. The decay rate is singular at each threshold as a consequence of the failure of the quadratic approximation to the worldline path integral. We argue that that higher-order effects will make the decay rates finite everywhere, and model those effects by the inclusion of hard thermal loop damping rates. We also demonstrate that the formalism developed here generalizes to the case of finite-temperature pair production in inhomogeneous fields. *

No abstract

This research brings together digital inequality scholars from across the Americas and Caribbean to examine efforts to tackle digital inequality in Uruguay, Chile, Peru, Brazil, Mexico, Cuba, Jamaica, the United States, and Canada. As the case studies show, governmental policy has an important role to play in reducing digital disparities, particularly for potential users in rural or remote areas, as well as populations with great economic disparities. We find that public policy can effectively reduce access gaps when it combines the trifecta of network, device, and skill provision, especially through educational institutions. We also note, that urban populations have benefitted from digital inclusion strategies to a greater degree. This underscores that, no matter the national context, rural-urban digital inequality (and often associated economic inequality) is resistant to change. Even when access is provided, potential users may not find it affordable, lack skills, and/or see no benefit in adoption. We see the greatest potential for future digital inclusion in two related approaches: 1) initiatives that connect with hard-to-reach, remote, and rural communities outside urban cores and 2) initiatives that learn from communities about how best to provide digital resources while respecting their diversely situated contexts, while meeting social, economic and political needs.

No abstract