192 research outputs found
Motional Ground State Cooling Outside the Lamb-Dicke Regime
We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground state population of 81(4)% after 100 ms of cooling, for the 85% of atoms that survive cooling and re-imaging. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the 3D motional ground state is possible, even without tight confinement and low initial temperature
Ultracold Molecular Assembly
Chemical reactions can be surprisingly efficient at ultracold temperatures ( < 1mK) due to the wave nature of atoms and molecules. The study of reactions in the ultracold regime is a new research frontier enabled by cooling and trapping techniques developed in atomic and molecular physics. In addition, ultracold molecular gases that offer diverse molecular internal states and large electric dipolar interactions are sought after for studies of strongly interacting many-body quantum physics. Here we propose a new approach for producing ultracold molecules in the absolute internal and motional quantum ground state, where single molecules are assembled one by one from individual atoms. The scheme involves laser cooling, optical trapping, Raman sideband cooling, and coherent molecular state transfer. As a crucial initial step, we demonstrate quantum control of constituent atoms, including 3D ground-state cooling of a single Cs atom, in a simple apparatus. As laser technology advances to shorter wavelengths, additional atoms will be amenable to laser-cooling, allowing more diverse, and eventually more complex, molecules to be assembled with full quantum control
Motional Ground State Cooling Outside the Lamb-Dicke Regime
We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground state population of 81(4)% after 100 ms of cooling, for the 85% of atoms that survive cooling and re-imaging. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the 3D motional ground state is possible, even without tight confinement and low initial temperature
Ultracold Molecular Assembly
Chemical reactions can be surprisingly efficient at ultracold temperatures ( < 1mK) due to the wave nature of atoms and molecules. The study of reactions in the ultracold regime is a new research frontier enabled by cooling and trapping techniques developed in atomic and molecular physics. In addition, ultracold molecular gases that offer diverse molecular internal states and large electric dipolar interactions are sought after for studies of strongly interacting many-body quantum physics. Here we propose a new approach for producing ultracold molecules in the absolute internal and motional quantum ground state, where single molecules are assembled one by one from individual atoms. The scheme involves laser cooling, optical trapping, Raman sideband cooling, and coherent molecular state transfer. As a crucial initial step, we demonstrate quantum control of constituent atoms, including 3D ground-state cooling of a single Cs atom, in a simple apparatus. As laser technology advances to shorter wavelengths, additional atoms will be amenable to laser-cooling, allowing more diverse, and eventually more complex, molecules to be assembled with full quantum control
Simplified Models for LHC New Physics Searches
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and we encourage them to continue and expand this effort,
which supplements both signature-based results and benchmark model
interpretations. A simplified model is defined by an effective Lagrangian
describing the interactions of a small number of new particles. Simplified
models can equally well be described by a small number of masses and
cross-sections. These parameters are directly related to collider physics
observables, making simplified models a particularly effective framework for
evaluating searches and a useful starting point for characterizing positive
signals of new physics. This document serves as an official summary of the
results from the "Topologies for Early LHC Searches" workshop, held at SLAC in
September of 2010, the purpose of which was to develop a set of representative
models that can be used to cover all relevant phase space in experimental
searches. Particular emphasis is placed on searches relevant for the first
~50-500 pb-1 of data and those motivated by supersymmetric models. This note
largely summarizes material posted at http://lhcnewphysics.org/, which includes
simplified model definitions, Monte Carlo material, and supporting contacts
within the theory community. We also comment on future developments that may be
useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results
from "Topologies for Early LHC Searches" workshop (SLAC, September 2010).
Supplementary material can be found at http://lhcnewphysics.or
Dark sectors 2016 Workshop: community report
This report, based on the Dark Sectors workshop at SLAC in April 2016,
summarizes the scientific importance of searches for dark sector dark matter
and forces at masses beneath the weak-scale, the status of this broad
international field, the important milestones motivating future exploration,
and promising experimental opportunities to reach these milestones over the
next 5-10 years
Determining the Impact of Probicon L28 and BioPlus 2B on Finishing Pig Growth Performance and Carcass Characteristics
These data represent the growth performance of pigs enrolled in a study to determine the impact of two direct fed microbial products on Salmonella and Escherichia coli prevalence pre- and post-harvest. A total of 650 finishing pigs in two groups were randomly assigned to pen via a completely randomized design, and pens were assigned to one of three treatments: 1) a control treatment with pigs fed a standard corn-soybean meal finishing diet (with no added probiotic); 2) the control diets with Probicon L28 (NexGen Innovations, LLC, Lubbock, TX) supplemented through water lines using a water medicator system at a target concentration of 1.0 × 106 CFU/head/day; and 3) the control diet with added BioPlus 2B (5.0 × 108 CFU/lb of feed; ~3.0 × 109 CFU/ head/day; CHR Hansen, Inc, Milwaukee, WI). No evidence of difference (P \u3e 0.10) between treatments was observed for overall ADG, ADFI, or F/G or any of the carcass traits. However, there was a tendency for a treatment effect for loin depth (P = 0.070). Pigs fed the BioPlus 2B treatment had numerically greater loin depth compared to other treatments, but there were no significant pairwise differences between treatments (P \u3e 0.05). The results of this study suggested that probiotics used in this study and supplied through the water or feed had no impact on growth or carcass characteristics of finishing pigs
- …