Synthetic clock transitions via continuous dynamical decoupling

Decoherence of quantum systems due to uncontrolled fluctuations of the environment presents fundamental obstacles in quantum science. `Clock' transitions which are insensitive to such fluctuations are used to improve coherence, however, they are not present in all systems or for arbitrary system parameters. Here, we create a trio of synthetic clock transitions using continuous dynamical decoupling in a spin-1 Bose-Einstein condensate in which we observe a reduction of sensitivity to magnetic field noise of up to four orders of magnitude; this work complements the parallel work by Anderson et al. (submitted, 2017). In addition, using a concatenated scheme, we demonstrate suppression of sensitivity to fluctuations in our control fields. These field-insensitive states represent an ideal foundation for the next generation of cold atom experiments focused on fragile many-body phases relevant to quantum magnetism, artificial gauge fields, and topological matter.Comment: 8 pages, 4 figures, Supplemental material

Perpetual emulation threshold of PT-symmetric Hamiltonians

We describe a technique to emulate a two-level \PT-symmetric spin Hamiltonian, replete with gain and loss, using only the unitary dynamics of a larger quantum system. This we achieve by embedding the two-level system in question in a subspace of a four-level Hamiltonian. Using an \textit{amplitude recycling} scheme that couples the levels exterior to the \PT-symmetric subspace, we show that it is possible to emulate the desired behaviour of the \PT-symmetric Hamiltonian without depleting the exterior, reservoir levels. We are thus able to extend the emulation time indefinitely, despite the non-unitary \PT dynamics. We propose a realistic experimental implementation using dynamically decoupled magnetic sublevels of ultracold atoms.Comment: 15 pages, 8 figure

Fourier transform spectroscopy of a spin-orbit coupled Bose gas

We describe a Fourier transform spectroscopy technique for directly measuring band structures, and apply it to a spin-1 spin-orbit coupled Bose-Einstein condensate. In our technique, we suddenly change the Hamiltonian of the system by adding a spin-orbit coupling interaction and measure populations in different spin states during the subsequent unitary evolution. We then reconstruct the spin and momentum resolved spectrum from the peak frequencies of the Fourier transformed populations. In addition, by periodically modulating the Hamiltonian, we tune the spin-orbit coupling strength and use our spectroscopy technique to probe the resulting dispersion relation. The frequency resolution of our method is limited only by the coherent evolution timescale of the Hamiltonian and can otherwise be applied to any system, for example, to measure the band structure of atoms in optical lattice potentials

Family Income Inequality and the Role of Wives Earnings in Mexico: 1988-2010

We study family income inequality in Mexico from 1988 to 2010. Female labor supply increased during this period, especially for married women. The share of wives’ income among married couples grew from 13 percent in 1988 to 23 percent in 2010. However, the correlation of husbands’ and wives’ earnings has been fairly stable with a value close to 0.28, one of the highest correlations recorded across countries. We follow Cancian and Reed’s (1999) methodology in order to analyze whether wives’ income equalizes total family income distribution. We investigate several counterfactuals and conclude that the recent increment in female employment has contributed to a decrease in family income inequality mainly through a rise in wives’ labor supply in poor families.income inequality, female employment, female earnings, Latin America, Mexico

El Entremés de la venta, de Quevedo

Los autores publican en este artículo una edición crítica del Entremés de la venta de don Francisco de Quevedo. El principal objetivo del artículo es la fijación textual y la redacción del aparato de notas. Análisis literarios más demorados se incluirán en un volumen de teatro completo que están preparando. The authors of this article publish a critical edition of Quevedo’s Entremés de la Venta. The main purpose of this article is the textual fixation and notes. A more detailed analysis of this interlude will be included in the volume of Quevedo’s theater that Arellano and García Valdés are preparing

Catálogo florístico del espacio natural de Doñana (SO de España). Plantas vasculares

Este catálogo sinóptico incluye todas las plantas vasculares nativas o naturalizadas que conforman la flora del Espacio Natural de Doñana, dentro del que están incluidos los parques Nacional y Natural de Doñana. Es uno de los resultados de un estudio sobre la flora y vegetación de dicho Espacio iniciado en 2003. Incluye 1386 taxones (especies y subespecies), para cada uno de los cuales se indica el nombre aceptado, sinónimos más usados, distribución general, distribución en el área de estudio por unidades corológicas, hábitat, frecuencia y citas previas. Se añaden comentarios breves sobre determinados taxones.This synoptic checklist comprises all vascular plants native o naturalized of the Natural Area of Doñana, which includes the National and Natural Parks of Doñana and all surrounding territories. This is one of the results of a study on the flora and vegetation of Doñana developed from 2003 on. This Checklist includes 1386 taxa (species and subspecies). For each taxon the following items are indicated: accepted name, selected synonyms, general distribution, distribution within the study area by chorological units, habitat, frequency and previous records. Some short comments are added for some of the taxa.Junta de Andalucía. Consejería de Medio Ambiente

Colossal magnon-phonon coupling in multiferroic Eu0.75_{0.75}Y0.25_{0.25}MnO3_3

We report the spectra of magnetically induced electric dipole absorption in Eu$_{0.75}$Y$_{0.25}$MnO$_3$ from temperature dependent far infrared spectroscopy (10-250 cm$^{-1}$). These spectra, which occur only in the $e||a$ polarization, consist of two relatively narrow electromagnon features that onset at $T_{FE}=30$ K and a broad absorption band that persists to temperatures well above $T_N=47$ K. The observed excitations account for the step up of the static dielectric constant in the ferroelectric phase. The electromagnon at 80 cm$^{-1}$ is observed to be strongly coupled to the nearby lowest optical phonon which transfers more than 1/2 of its spectral weight to the magnon. We attribute the origin of the broad background absorption to the two magnon emission decay process of the phonon.Comment: 4 pages, 3 figure