RESUMEN
We perform first-principles quantum simulations of dissociation of trapped, spatially inhomogeneous Bose-Einstein condensates of molecular dimers. Specifically, we study spatial pair correlations of atoms produced in dissociation after time of flight. We find that the observable correlations may significantly degrade in systems with spatial inhomogeneity compared to the predictions of idealized uniform models. We show how binning of the signal can enhance the detectable correlations and lead to the violation of the classical Cauchy-Schwartz inequality and relative number squeezing.
RESUMEN
We numerically show that a topologically nontrivial 3D Skyrmion can be energetically stable in a trapped two-component atomic Bose-Einstein condensate, for the parameters of 87Rb condensate experiments. The separate conservation of the two atomic species can stabilize the Skyrmion against shrinking to zero size, while drift of the Skyrmion due to the trap-induced density gradient can be prevented by rotation or by a laser potential.
RESUMEN
A multimode model of a continuously pumped atom laser is shown to be unstable below a critical value of the scattering length. Above the critical scattering length, the atom laser reaches a steady state, the stability of which increases with pumping. Below this limit the laser does not reach a steady state. This instability results from the competition between gain and loss for the excited states of the lasing mode. It will determine a fundamental limit for the linewidth of an atom laser beam.
RESUMEN
The purpose of this study was to compare low-dose (LD) and high-dose (HD) systemic heparinization in a prospective randomized study of arteriovenous carbon dioxide removal (AVCO2R) during acute respiratory distress syndrome, using a commercially available heparin-coated oxygenator. Adult sheep (n = 13) received an LD50 smoke inhalation and 40% TBSA third degree cutaneous flame burn injury. At 40-48 h post-injury, animals underwent cannulation of the carotid artery and jugular vein and were then randomized to HD heparin (activated clotting time, ACT > 300s, n = 6) and LD heparin (ACT < 200s, n =7) and placed on AVCO2R for approximately 72 h using an oxygenator with the Trillium Bio-Passive Surface. Mean ACTs were significantly different, as expected (HD: 446 +/- 26s, LD: 213 +/- 12s, p < 0.05). AVCO2R shunt flow averaged approximately 13% of cardiac output with mean CO2 removal similar in HD and LD, p = NS. The hematocrit, platelet count, and fibrin degradation products for the two groups were not different. No differences in thrombosis or bleeding were noted. In conclusion, LD systemic heparin (ACT < 200s) with a heparin-coated oxygenator does not increase thrombogenicity during AVCO2R for smoke/burn-induced severe lung injury in sheep.
Asunto(s)
Dióxido de Carbono/sangre , Oxigenación por Membrana Extracorpórea/métodos , Heparina/farmacología , Enfermedad Aguda , Animales , Derivación Arteriovenosa Quirúrgica/métodos , Derivación Arteriovenosa Quirúrgica/normas , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Materiales Biocompatibles Revestidos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Oxigenación por Membrana Extracorpórea/efectos adversos , Oxigenación por Membrana Extracorpórea/normas , Femenino , Fibrinógeno/efectos de los fármacos , Fibrinógeno/metabolismo , Heparina/administración & dosificación , Oxigenadores de Membrana/normas , Recuento de Plaquetas , Insuficiencia Respiratoria/complicaciones , Insuficiencia Respiratoria/terapia , Ovinos , Resultado del Tratamiento , Tiempo de Coagulación de la Sangre TotalRESUMEN
We calculate amplitude squeezing spectra for the light from a variety of conventionally pumped three- and four-level lasers. Hence we extend a recent prediction that a certain three-level laser can generate nonclassical light without the need for rigged pumping.
