Breakdown of integrability in a quasi-one-dimensional ultracold bosonic gas

We demonstrate that virtual excitations of higher radial modes in an atomic Bose gas in a tightly confining waveguide result in effective three-body collisions that violate integrability in this quasi-one-dimensional quantum system and give rise to thermalization. The estimated thermalization rates are consistent with recent experimental results in quasi-1D dynamics of ultracold atoms.Comment: 4 pages, 3 figures, revtex

El (re)conocimiento de la madre en "La mitad del alma"

"La mitad del alma" de Carme Riera, en que C rememora a su madre, enfatiza la importancia del reconocimiento de las mujeres en la memoria histórica. Desde el mito griego de Atena, quien ignoraba a su madre Metis, la sociedad patriarcal ha excluido a la madre, lo cual promete que la hija conlleve negación también, según Amber Jacobs en "On Matricide". Jacobs observa que en "La Oresteia" hay crímenes sancionados contra las mujeres, las hijas están deprimidas, existe incesto contra la hija, la reproducción familiar se paraliza, toda la sociedad sufre y la hija se desperdicia también cuando la madre es menospreciada. Jacobs afirma que este desprecio de la madre que transcurría en los mitos griegos continúa en la sociedad y la psicología hoy en día. En esta novela de Riera, la hija protagonista, quien desconoce a su madre, sufre de un estado depresivo, la falta de creatividad y una conexión demasiado fuerte con su padre, semejante a lo que Jacobs observa en los mitos, pero la escritura de C sobre su madre la integrará en la consciencia y mejorará la situación de la hija y, últimamente, la de toda la civilización.Carme Rieras "La mitad del alma", in which C recollects her mother, emphasizes the importance of the recognition of women in historic memory. Ever since the Greek myth of Athena, who was ignorant of the existence of her mother, Metis, patriarchal society has excluded the mother, a fact which promises that the daughter will also experience negation, according to Amber Jacobs in "On Matricide". Jacobs observes that in "La Oresteia" there are sanctioned crimes against women, the daughters are depressed, there is incest against the daughter, she is dishonored, family reproduction stops, and all of society suffers when the mother is not appreciated. Jacobs affirms that the distain of the mother that took place in Greek myths continues in society and psychology today. In this novel by Riera, the protagonist/daughter, who does not know much about her mother, suffers from depression, lack of creativity, and an overly strong connection with her father, similar to what Jacobs has observed in myths. However, C‟s act of writing about her mother integrates her into C‟s consciousness, improving the situation of the daughter and, ultimately, that of all of civilization.peerReviewe

Metaphor, metonymy, and mirrors: Female self-reflection in contemporary Spanish novels by women

Dissertation (Ph.D.)--University of Kansas, Spanish and Portuguese, 1993.After the Spanish Civil War (1936-39), novels by women, many of which explore female identity, began to proliferate in Spain. The works examined in this study--Nada, Primera memoria, La placa del Diamant, Julia, El cuarto de atras, El amor es un juego solitario, and Cuestion de amor propio--were published between 1945 and 1988, and feature female protagonists struggling for self-realization and autonomy. Each chapter of this study presents an analysis of one of the seven novels, demonstrating how examination of metaphors, metonymy, and mirror images reveals the protagonist's development. Because metaphor and metonymy are basic tropes of expression, and often reveal subconscious processes, I demonstrate how these tropes illuminate the course of changing identity that the protagonist undergoes. While metaphors convey equivalent expressions that help to transmit meaning, metonymy moves on to associated ideas, and frequently demonstrates change and growth. I examine the metaphors used to describe the protagonist's feelings, and show how subsequent metonymic associations alter the original meaning. Further, the study focuses on mirror scenes and other mirroring devices that illustrate development (such as mother-daughter relationships, references to fairy tales, intimate communication with a friend, and telling or writing one's own story). I explain how "mirroring" serves both a metaphoric and a metonymic function, and the way the mirror also acts as a trope that reveals modifications in the protagonist's personality. In addition to the individual evolution of each of the protagonists, my study also underscores the changing socio-political role of women in Spain between 1945 and 1988. Franco's dictatorship (1939-75) created a stifling atmosphere for women. However, my analysis of the metaphors, metonymy, and mirror images in these works indicates a desire to change this repressive situation, and a gradual transformation of women's circumstances in Spain

Adiabatic radio frequency potentials for the coherent manipulation of matter waves

Adiabatic dressed state potentials are created when magnetic sub-states of trapped atoms are coupled by a radio frequency field. We discuss their theoretical foundations and point out fundamental advantages over potentials purely based on static fields. The enhanced flexibility enables one to implement numerous novel configurations, including double wells, Mach-Zehnder and Sagnac interferometers which even allows for internal state-dependent atom manipulation. These can be realized using simple and highly integrated wire geometries on atom chips.Comment: 13 pages, 2 figure

An optical lattice on an atom chip

Optical dipole traps and atom chips are two very powerful tools for the quantum manipulation of neutral atoms. We demonstrate that both methods can be combined by creating an optical lattice potential on an atom chip. A red-detuned laser beam is retro-reflected using the atom chip surface as a high-quality mirror, generating a vertical array of purely optical oblate traps. We load thermal atoms from the chip into the lattice and observe cooling into the two-dimensional regime where the thermal energy is smaller than a quantum of transverse excitation. Using a chip-generated Bose-Einstein condensate, we demonstrate coherent Bloch oscillations in the lattice.Comment: 3 pages, 2 figure

Ultracold atoms in radio-frequency-dressed potentials beyond the rotating wave approximation

We study dressed Bose-Einstein condensates in an atom chip radio-frequency trap. We show that in this system sufficiently strong dressing can be achieved to cause the widely used rotating wave approximation (RWA) to break down. We present a full calculation of the atom - field coupling which shows that the non-RWA contributions quantitatively alter the shape of the emerging dressed adiabatic potentials. The non-RWA contributions furthermore lead to additional allowed transitions between dressed levels. We use RF spectroscopy of Bose-Einstein condensates trapped in the dressed state potentials to directly observe the transition from the RWA to the beyond-RWA regime.Comment: 6 pages, 4 figure

Dual-species quantum degeneracy of potassium-40 and rubidium-87 on an atom chip

In this article we review our recent experiments with a 40K-87Rb mixture. We demonstrate rapid sympathetic cooling of a 40K-87Rb mixture to dual quantum degeneracy on an atom chip. We also provide details on efficient BEC production, species-selective magnetic confinement, and progress toward integration of an optical lattice with an atom chip. The efficiency of our evaporation allows us to reach dual degeneracy after just 6 s of evaporation - more rapidly than in conventional magnetic traps. When optimizing evaporative cooling for efficient evaporation of 87Rb alone we achieve BEC after just 4 s of evaporation and an 8 s total cycle time.Comment: 8 pages, 4 figures. To be published in the Proceedings of the 20th International Conference on Atomic Physics, 2006 (Innsbruck, Austria

Prospects for measuring the 229Th isomer energy using a metallic magnetic microcalorimeter

The Thorium-229 isotope features a nuclear isomer state with an extremely low energy. The currently most accepted energy value, 7.8 +- 0.5 eV, was obtained from an indirect measurement using a NASA x-ray microcalorimeter with an instrumental resolution 26 eV. We study, how state-of-the-art magnetic metallic microcalorimeters with an energy resolution down to a few eV can be used to measure the isomer energy. In particular, resolving the 29.18 keV doublet in the \gamma-spectrum following the \alpha-decay of Uranium-233, corresponding to the decay into the ground and isomer state, allows to measure the isomer transition energy without additional theoretical input parameters, and increase the energy accuracy. We study the possibility of resolving the 29.18 keV line as a doublet and the dependence of the attainable precision of the energy measurement on the signal and background count rates and the instrumental resolution.Comment: 32 pages, 8 figures, eq. (3) correcte

Quantum noise thermometry for bosonic Josephson junctions in the mean field regime

Bosonic Josephson junctions can be realized by confining ultracold gases of bosons in multi-well traps, and studied theoretically with the $M$-site Bose-Hubbard model. We show that canonical equilibrium states of the $M$-site Bose-Hubbard model may be approximated by mixtures of coherent states, provided the number of atoms is large and the total energy is comparable to $k_BT$. Using this approximation, we study thermal fluctuations in bosonic Josephson junctions in the mean field regime. Statistical estimates of the fluctuations of relative phase and number, obtained by averaging over many replicates of an experiment, can be used to estimate the temperature and the tunneling parameter, or to test whether the experimental procedure is effectively sampling from a canonical thermal equilibrium ensemble.Comment: Accepted for Phys. Rev.