B-modes and the Nature of Inflation

Observations of the cosmic microwave background do not yet determine whether inflation was driven by a slowly-rolling scalar field or involved another physical mechanism. In this paper we discuss the prospects of using the power spectra of scalar and tensor modes to probe the nature of inflation. We focus on the leading modification to the slow-roll dynamics, which entails a sound speed $c_s$ for the scalar fluctuations. We derive analytically a lower bound on $c_s$ in terms of a given tensor-to-scalar ratio $r$, taking into account the difference in the freeze-out times between the scalar and tensor modes. We find that any detection of primordial B-modes with $r > 0.01$ implies a lower bound on $c_s$ that is stronger than the bound derived from the absence of non-Gaussianity in the Planck data. For $r \gtrsim 0.1$, the bound would be tantalizingly close to a critical value for the sound speed, $(c_s)_\star = 0.47$ (corresponding to $(f_{\rm NL}^{\rm equil})_\star = -0.93$), which we show serves as a threshold for non-trivial dynamics beyond slow-roll. We also discuss how an order-one level of equilateral non-Gaussianity is a natural observational target for other extensions of the canonical paradigm.Comment: 25+7 pages, 9 figures. Published versio

Skills, exports, and the wages of five million Latin American workers

The returns to schooling or the skill premium is a key parameter in various literatures, including globalization and inequality and international migration. This paper explores the skill premium and its link to exports in Latin America, thus linking the skill premium to the emerging literature on the structure of trade and development. Using data on employment and wages for over five million workers in sixteen Latin American economies, the authors estimate national and industry-specific skill premiums and study some of their determinants. The evidence suggests that both country and industry characteristics are important in explaining skill premiums. The analysis also suggests that the incidence of exports within industries, the average income per capita within countries, and the relative abundance of skilled workers are related to the underlying industry and country characteristics that explain skill premiums. In particular, higher sectoral exports are positively linked with the skill premium at the industry level, a result that supports recent trade models linking exports with wages and the demand for skills.Labor Markets,Water and Industry,Tertiary Education,Labor Policies,Inequality

Skills, Exports, and the Wages of Seven Million Latin American Workers

The returns to schooling and the skill premium are key parameters in various fields and policy debates, including the literatures on globalization and inequality, international migration, and technological change. This paper explores the skill premium and its correlation with exports in Latin America, thus linking the skill premium to the emerging literature on the structure of trade and development. Using data on employment and wages for over seven million workers from sixteen Latin American economies, the authors estimate national and industry-specific returns to schooling and skill premiums and study some of their determinants. The evidence suggests that both country and industry characteristics are important in explaining returns to schooling and skill premiums. The analyses also suggest that the incidence of exports within industries, the average income per capita within countries, and the relative abundance of skilled workers are related to the underlying industry and country characteristics that explain these parameters. In particular, sectoral exports are positively correlated with the skill premium at the industry level, a result that supports recent trade models linking exports with wages and the demand for skills.

Defining Virtual Worlds: Main Features and Regulatory Challenges

This issue paper pursues three goals. First, it aims to identify a definition of virtual worlds that is shared among stakeholders. There are many possible ways to define virtual worlds and the metaverse that differ sensibly depending on the sector, the use case at hand, or the sensibility of those employing the terms. The European Commission (EC)’s call for evidence for a non-legislative initiative on virtual worlds (April 2023)1 has made things even more complicated. While it employs the term ‘metaverse’ abundantly in its advertising campaign (website, social media, and so on), it uses only ‘virtual words’ in the text of the call itself. Clarifying the boundaries of the two notions is thus necessary, to both making sure we all debate over the same subject matter, and for policy makers to target policy intervention at the appropriate issues. This part concludes by providing a definition of virtual worlds. Second, on the basis of the definitions settled in the first part, this paper identifies the main characteristics of virtual worlds, and highlights a set of challenging features that are relevant for the debate. And third, based on the identified challenging features, the paper raises a set of questions aimed at identifying possible regulatory gaps or topics that might require attention by policy makers

Signals of a Quantum Universe

Structure in the Universe is widely believed to have originated from quantum fluctuations during an early epoch of accelerated expansion. Yet, the patterns we observe today do not distinguish between quantum or classical primordial fluctuations; current cosmological data is consistent with either possibility. We argue here that a detection of primordial non-Gaussianity can resolve the present situation, and provide a litmus-test for the quantum origin of cosmic structure. Unlike in quantum mechanics, vacuum fluctuations cannot arise in classical theories and therefore long-range classical correlations must result from (real) particles in the initial state. Similarly to flat-space scattering processes, we show how basic principles require these particles to manifest themselves as poles in the $n$-point functions, in the so-called folded configurations. Following this observation, and assuming fluctuations are (i) correlated over large scales, and (ii) generated by local evolution during an inflationary phase, we demonstrate that: the absence of a pole in the folded limit of non-Gaussian correlators uniquely identifies the quantum vacuum as the initial state. In the same spirit as Bell's inequalities, we discuss how this can be circumvented if locality is abandoned. We also briefly discuss the implications for simulations of a non-Gaussian universe.Comment: 17 pages. 2 figure

A mapping of labor mobility costs in the developing world

Estimates of labor mobility costs are needed to assess the responses of employment and wages to a trade shock when factor adjustment is costly. Available methods to estimate those costs rely on panel data, which are seldom available in developing countries. In this paper, we propose a method to estimate mobility costs using data that is more easily obtainable worldwide. Our estimator matches observed employment flows with those flows predicted by a model of costly labor adjustment. We estimate a mapping of labor mobility costs for the developing world and we use those estimates to explore the response of labor markets (wages and employment) to trade policy.Centro de Estudios Distributivos, Laborales y Sociales (CEDLAS

A mapping of labor mobility costs in the developing world

Estimates of labor mobility costs are needed to assess the responses of employment and wages to a trade shock when factor adjustment is costly. Available methods to estimate those costs rely on panel data, which are seldom available in developing countries. In this paper, we propose a method to estimate mobility costs using data that is more easily obtainable worldwide. Our estimator matches observed employment flows with those flows predicted by a model of costly labor adjustment. We estimate a mapping of labor mobility costs for the developing world and we use those estimates to explore the response of labor markets (wages and employment) to trade policy.Centro de Estudios Distributivos, Laborales y Sociales (CEDLAS

Exporters, engineers, and blue-collarworkers

This article investigates differences in the composition of employment between exporting and nonexporting firms. In particular, it asks whether exporting firms hire more engineers relative to blue-collar workers than nonexporting firms. In a stylized partialequilibrium model, firms produce goods of varying quality and exporters tend to produce higher quality goods, which are intensive in engineers relative to blue-collar workers. Firms are heterogeneous and more productive firms become exporters and have a higher demand for engineers. The article provides causal evidence in support of these theories using the Chilean Encuesta Nacional Industrial Anual (ENIA), an annual census of manufacturing firms. The results from an instrumental variable estimator suggest that Chilean exporters indeed utilize a higher share of engineers over blue-collar workers.Facultad de Ciencias Económica