Are back-to-back particle--antiparticle correlations observable in high energy nuclear collisions?

Analytical formulae are presented which provide quantitative estimates for the suppression of the anticipated back-to-back particle--antiparticle correlations in high energy nuclear collisions due to the finite duration of the transition dynamics. They show that it is unlikely to observ the effect.Comment: Short Note, 4 pages, 2 figure

Labor Market Institutions, Wages and Investment

Labor market institutions, via their effect on the wage structure, affect the investment decisions of firms in labor markets with frictions. This observation helps explain rising wage inequality in the US, but a relatively stable wage structure in Europe in the 1980s. These different trends are the result of different investment decisions by firms for the jobs typically held by less-skilled workers. Firms in Europe have more incentives to invest in less-skilled workers, because minimum wages or union contracts mandate that relatively high wages have to be paid to these workers. I report some empirical evidence for investments in training and physical capital across the Atlantic, which is roughly in line with this theoretical reasoning.frictional labor markets, human capital, changes in wage inequality

Decoherence and oscillations of supernova neutrinos

Supernova neutrinos have several exceptional features which can lead to interesting physical consequences. At the production point their wave packets have an extremely small size $\sigma_x \sim 10^{-11}$ cm; hence the energy uncertainty can be as large as the energy itself, $\sigma_E \sim E$, and the coherence length is short. On the way to the Earth the wave packets of mass eigenstates spread to macroscopic sizes and separate. Inside the Earth the mass eigenstates split into eigenstates in matter and oscillate again. The coherence length in the Earth is comparable with the radius of the Earth. We explore these features and their consequences. (i) We present new estimates of the wave packet size. (ii) We consider the decoherence condition for the case of wave packets with spatial spread and show that it is not modified by the spread. (iii) We study the coherence of neutrinos propagating in a multi-layer medium with density jumps at the borders of layers. In this case coherence can be partially restored due to a "catch-up effect", increasing the coherence length beyond the usual estimate. This catch-up effect can occur for supernova neutrinos as they cross the shock wave fronts in the exploding star or the core of the Earth.Comment: 32 pages + references; v2: added minor clarifications and references, matches published versio

What is the Effect of the Current Financial Crisis on Venture Capital Financing? Empirical Evidence from US Internet Start-ups

Employing a large dataset regarding venture capital investments in US Internet firms, we analyze the effect of the current financial crisis on the venture capital market. Using regression analysis, we find that the financial crisis led to a 20% decrease in the average amount of funds raised per funding round. This effect, however, can only be found in later funding rounds. We argue that firms in later financing rounds that need capital to survive cannot avoid a deduction induced by the financial crisis, whereas firms that seek initial funding postpone their funding and expansion plans until the capital markets have stabilized. Furthermore, firms in later phases of the venture cycle are more likely to be negatively affected by the weak IPO market than firms seeking initial funding. Our results suggest that the financial crisis can lead to a severe "funding gap" in the financing of technological development and innovation.Entrepreneurship; Financial Crisis; Venture Capital; Innovation Finance