Influence Functional for Decoherence of Interacting Electrons in Disordered Conductors

We have rederived the controversial influence functional approach of Golubev and Zaikin (GZ) for interacting electrons in disordered metals in a way that allows us to show its equivalence, before disorder averaging, to diagrammatic Keldysh perturbation theory. By representing a certain Pauli factor (1-2 rho) occuring in GZ's effective action in the frequency domain (instead of the time domain, as GZ do), we also achieve a more accurate treatment of recoil effects. With this change, GZ's approach reproduces, in a remarkably simple way, the standard, generally accepted result for the decoherence rate. -- The main text and appendix A.1 to A.3 of the present paper have already been published previously; for convenience, they are included here again, together with five additional, lengthy appendices containing relevant technical details.Comment: Final version, as submitted to IJMPB. 106 pages, 11 figures. First 16 pages contain summary of main results. Appendix A summarizes key technical steps, with a new section A.4 on "Perturbative vs. Nonperturbative Methods". Appendix C.4 on thermal weighting has been extended to include discussion [see Eqs.(C.22-24)] of average energy of electron trajectorie

Nothing but Relativity, Redux

Here we show how spacetime transformations consistent with the principle of relativity can be derived without an explicit assumption of the constancy of the speed of light, without gedanken experiments involving light rays, and without an assumption of differentiability, or even continuity, for the spacetime mapping. Hence, these historic results could have been derived centuries ago, even before the advent of calculus. This raises an interesting question: Could Galileo have derived Einsteinian relativity

God and the Global Economy: Religion and Attitudes Towards Trade and Immigration in the United States

Using the results of a national identity survey, we test the impact of religious affiliation on trade and immigration-policy preferences of US residents while controlling for individual level of skill, political ideology and other important demographic characteristics. Our results show that religion is an important determinant of international-policy preferences as individuals who are pre-Vatican II Catholic or members of a fundamentalist Protestant denomination are more likely to prefer policies that restrict imports and immigration. Religiosity, in contrast, has a separate effect of moderating attitudes towards immigration. In addition, we find evidence of denominational effects among African Americans in that members of fundamentalist denominations tend to favour policies that restrict imports while others do not, implying that statistical results commonly attributed to racial effects may actually be a religion effect

Transportation Costs and U.S. Manufacturing FDI

In empirical models of foreign direct investment (FDI), distance is most often used to proxy for transportation costs and other pure-trade costs. Given that distance is time invariant but transportation costs are not, this approach is less than satisfactory when actual transportation costs rise and fall over time.The contribution of this work is to explicitly control for transportation costs and thereby better understand their impact on FDI. We explore the impact of shipping costs on total US FDI stocks abroad, manufacturing stocks and service stocks using measures of sea-shipping and air-shipping costs in a Hausman–Taylor model that controls for endogeneity and allows for time-invariant variables such as distance. We find that transportation costs have a positive and statistically significant relationship with US total and manufacturing FDI, suggesting a substitute relationship between FDI and trade flows consistent with horizontal MNE activity. As one would expect, these costs are insignificant for service stocks

(WP 2010-03) Subsidizing Religious Participation through Groups: A Model of the Megachurch Strategy for Growth

Either despite or because of their non-traditional approach, megachurches have grown significantly in the United States since 1980. This paper models religious participation as an imperfect public good which, absent intervention, yields suboptimal participation by members from the church’s perspective. Megachurches address this problem by employing secular based group activities to subsidize religious participation in an effort to increase attendees’ religious investment. This strategy not only allows megachurches to attract and retain new members when many traditional churches are losing members, but also results in higher levels of individual satisfaction thereby allowing the megachurch to raise levels of commitment and faith practices. Data from the FACT2000 survey provide evidence that megachurches employ groups more extensively than other churches and this approach is consistent with a strategy to use the provision of groups to help subsidize individuals’ religious investment. Religious capital rises among members of megachurches relative to members of non-megachurches as a result of this strategy

(WP 2010-07) Examining Megachurch Growth: Free Riding, Fit, and Faith

Megachurches are thriving in religious markets at a time when Americans are asserting their ability as consumers of religious products to engage in religious switching. The apparent success of megachurches, which often provide a low cost and low commitment path by which religious refugees may join the church, seems to challenge Iannocconne’s theory that high commitment churches will thrive while low commitment churches will atrophy. This paper employs a signaling model to illustrate the strategy and organizational forms megachurches employ to indicate a match between what the church produces and the religious refugee wishes to consume in an effort to increase their membership. The model illustrates that megachurches expect little in regard to financial or time commitment of new attendees. However, once the attendees perceive a good fit with the church, the megachurch increases its expectation of commitment. Data from the FACT2000 survey provide evidence in support of the model’s predictions