Singularity resolution depends on the clock

We study the quantum cosmology of a flat Friedmann–Lemaître–Robertson–Walker Universe filled with a (free) massless scalar field and a perfect fluid that represents radiation or a cosmological constant whose value is not fixed by the action, as in unimodular gravity. We study two versions of the quantum theory: the first is based on a time coordinate conjugate to the radiation/dark energy matter component, i.e., conformal time (for radiation) or unimodular time. As shown by Gryb and Thébault, this quantum theory achieves a type of singularity resolution; we illustrate this and other properties of this theory. The theory is then contrasted with a second type of quantisation in which the logarithm of the scale factor serves as time, which has been studied in the context of the 'perfect bounce' for quantum cosmology. Unlike the first quantum theory, the second one contains semiclassical states that follow classical trajectories and evolve into the singularity without obstruction, thus showing no singularity resolution. We discuss how a complex scale factor best describes the semiclassical dynamics. This cosmological model serves as an illustration of the problem of time in quantum cosmology

Sepharadim/conversos and premodern Global Hispanism

Sepharadim participated in the Hispanic vernacular culture of the Iberian Peninsula. Even in the time of al-Andalus many spoke Hispano-Romance, and even their Hebrew literature belies a deep familiarity with and love of their native Hispano-Romance languages. However, since the early sixteenth century the vast majority of Sepharadim have never lived in the Hispanic world. Sepharadim lived not in Spanish colonies defined by Spanish conquest, but in a network of Mediterranean Jewish communities defined by diasporic values and institutions. By contrast, the conversos, those Sepharadim who converted to Catholicism, whether in Spain or later in Portugal, Italy, or the New World, lived mostly in Spanish Imperial lands, were officially Catholic, and spoke normative Castilian. Their connections, both real and imagined, with Sephardic cultural practice put them at risk of social marginalization, incarceration, even death. Some were devout Catholics whose heritage and family history doomed them to these outcomes. Not surprisingly, many Spanish and Portugese conversos sought refuge in lands outside of Spanish control where they might live openly as Jews. This exodus (1600s) from the lands formerly known as Sefarad led to a parallel Sephardic community of what conversos who re-embraced Judaism in Amsterdam and Italy by a generation of conversos trained in Spanish universities. The Sephardic/Converso cultural complex exceeds the boundaries of Spanish imperial geography, confuses Spanish, Portuguese, Catholic, and Jewish subjectivities, and defies traditional categories practiced in Hispanic studies, and are a unique example of the Global Hispanophone

V. I. P. (gent il·lustre que he conegut)

Personatges com Manuel Azaña, Ramon Menéndez Pidal, H. G. Wells, Aldous Huxley, Carles Riba..

[Estoria de España]

Precede ao título: Universidad de Madrid-Facultad de Filosofía y Letras. Seminario Menéndez PidalT. I (CXXXII, 320 p.) -- t. II (CXL-CCVIII, 322-853 p.)Texto a dúas columna

Casas, Bartolomé de Las (Seville 1484–Madrid 1566)

Las Casa