92 research outputs found
Spatial separation in a thermal mixture of ultracold Yb and Rb atoms
We report on the observation of unusually strong interactions in a thermal
mixture of ultracold atoms which cause a significant modification of the
spatial distribution. A mixture of Rb and Yb with a temperature
of a few K is prepared in a hybrid trap consisting of a bichromatic
optical potential superimposed on a magnetic trap. For suitable trap parameters
and temperatures, a spatial separation of the two species is observed. We infer
that the separation is driven by a large interaction strength between
Yb and Rb accompanied by a large three-body recombination rate.
Based on this assumption we have developed a diffusion model which reproduces
our observations
The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords
Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we systematically evaluate how simulated plume structure and submarine melt during summer months depends on realistic ranges of subglacial discharge, glacier depth, and ocean stratification from 12 Greenland fjords. Our results show that grounding line depth is a strong control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-trapped plumes that can overcut termini. Due to sustained upwelling velocities, plumes in cold, shallow fjords can induce equivalent depth-averaged melt rates compared to warm, deep fjords. These results detail a direct ocean-ice feedback that can affect the Greenland Ice Sheet
Formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics
Progress on researches in the field of molecules at cold and ultracold
temperatures is reported in this review. It covers extensively the experimental
methods to produce, detect and characterize cold and ultracold molecules
including association of ultracold atoms, deceleration by external fields and
kinematic cooling. Confinement of molecules in different kinds of traps is also
discussed. The basic theoretical issues related to the knowledge of the
molecular structure, the atom-molecule and molecule-molecule mutual
interactions, and to their possible manipulation and control with external
fields, are reviewed. A short discussion on the broad area of applications
completes the review.Comment: to appear in Reports on Progress in Physic
A Cytoplasmic Complex Mediates Specific mRNA Recognition and Localization in Yeast
The localization of ash mRNA in yeast requires the binding of She2p and the myosin adaptor protein She3p to its localization element, which is highly specific and leads to the assembly of stable transport complexes
Belle II Vertex Detector Performance
The Belle II experiment at the SuperKEKB accelerator (KEK, Tsukuba, Japan) collected its first e+e− collision data in the spring 2019. The aim of accumulating a 50 times larger data sample than Belle at KEKB, a first generation B-Factory, presents substantial challenges to both the collider and the detector, requiring not only state-of-the-art hardware, but also modern software algorithms for tracking and alignment.
The broad physics program requires excellent performance of the vertex detector, which is composed of two layers of DEPFET pixels and four layers of double sided-strip sensors. In this contribution, an overview of the vertex detector of Belle II and our methods to ensure its optimal performance, are described, and the first results and experiences from the first physics run are presented
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