Radio Frequency Association of Efimov Trimers

The quantum-mechanical three-body problem is one of the fundamental challenges of few-body physics. When the two-body interactions become resonant, an infinite series of universal three-body bound states is predicted to occur, whose properties are determined by the strength of the two-body interactions. We report on the association and direct observation of a trimer state consisting of three distinguishable fermions using radio-frequency (RF) spectroscopy. The measurements of its binding energy are consistent with theoretical predictions which include non-universal corrections.Comment: 12 pages, 6 figure

Collisional stability of a three-component degenerate Fermi gas

We report on the creation of a degenerate Fermi gas consisting of a balanced mixture of atoms in three different hyperfine states of $^6$Li. This new system consists of three distinguishable Fermions with different and tunable interparticle scattering lengths $a_{12}$, $a_{13}$ and $a_{23}$. We are able to prepare samples containing $5 \cdot 10^4$ atoms in each state at a temperature of about $215$nK, which corresponds to $T/T_F \approx 0.37$. We investigated the collisional stability of the gas for magnetic fields between 0 and 600 G and found a prominent loss feature at 130 G. From lifetime measurements we determined three-body loss coefficients, which vary over nearly three orders of magnitude

Implementing the Massachusetts Child Trauma Project (MCTP) to Improve Services for Children with Complex Trauma in Child Welfare: Phase I Needs and Readiness Assessment

MCTP seeks to improve placement stability and outcomes for children with complex trauma in the care of the Massachusetts Department of Children and Families (DCF) by creating a sustainable capacity for providing evidence-based trauma interventions within provider agencies, and trauma-informed practices within DCF

Atom-Dimer Scattering in a Three-Component Fermi Gas

Ultracold gases of three distinguishable particles with large scattering lengths are expected to show rich few-body physics related to the Efimov effect. We have created three different mixtures of ultracold 6Li atoms and weakly bound 6Li2 dimers consisting of atoms in three different hyperfine states and studied their inelastic decay via atom-dimer collisions. We have found resonant enhancement of the decay due to the crossing of Efimov-like trimer states with the atom-dimer continuum in one mixture as well as minima of the decay in another mixture, which we interpret as a suppression of exchange reactions of the type |12>+|3> -> |23>+|1>. Such a suppression is caused by interference between different decay paths and demonstrates the possiblity to use Efimov physics to control the rate constants for molecular exchange reactions in the ultracold regime.Comment: 5 pages, 3 figure

Helping Children Through Evidence-based Trauma Treatments, Initial Findings from the Massachusetts Child Trauma Project (MCTP)

Background-The Massachusetts Child Trauma Project (MCTP) is a statewide collaboration to implement improvements to the Massachusetts child welfare system in order to increase access to trauma services for children within the system. Purpose-This analysis compares PTSD symptoms and other behavioral and functional impairments at baseline and at 6-month follow-up/discharge among children enrolled in MCTP. Methods-The 166 clinicians trained in MCTP were required to enroll 2-3 children in the care of DCF into the evaluation process. Descriptive statistics were performed on the 300 children enrolled at baseline, as of Fall 2013. Paired t-tests were performed on the 73 children who had follow-up data to assess longitudinal differences in symptoms, behaviors, impairments, and functioning. Results-The baseline results indicate that children enrolled in MCTP present with clinical levels of symptoms of PTSD and behavioral/functional impairment. There were statistically significant decreases in PTSD severity (p=0.005), according to the UCLA PTSD Index Child/Adolescent Version. Additionally, internalizing behaviors, such as anxiety and/or depression, decreased (p=0.05), as assessed by the Child Behavior Checklist. However, the UCLA PTSD Index Parent Version and the externalizing measure of the Child Behavior Checklist showed symptom reduction, but were not statistically significant. Clinician reported progress, ascertained by the Child and Adolescent Needs and Strengths (CANS), showed mixed findings. Conclusion-While there was no comparison group, these results suggest that the trauma treatments provided by MCTP trained mental health providers is reducing symptamotolgy and improving functioning among children in DCF care who experienced trauma. Baseline findings indicate that most children present with symptoms in the clinical range of PTSD and other trauma-related impairments, while longitudinal results show that these children are experiencing symptom reduction, and improved functioning, suggesting that the trainings that MCTP has provided have been effective

A Universal Trimer in a Three-Component Fermi Gas

We show that the recently measured magnetic field dependence of three-body loss in a three-component mixture of ultracold $^6$Li atoms [1,2] can be explained by the presence of a universal trimer state. Previous work suggested a universal trimer state as a probable explanation, yet failed to get good agreement between theory and experiment over the whole range of magnetic fields. For our description we adapt the theory of Braaten and Hammer [3] for three identical bosons to the case of three distinguishable fermions by combining the three scattering lengths $a_{12},$ $a_{23}$ and $a_{13}$ between the three components to an effective interaction parameter $a_m$. We show that taking into account a magnetic field variation of the lifetime of the trimer state is essential to obtain a complete understanding of the observed decay rates.Comment: 5 pages, 3 figure

Results of the LIVE-L3A Experiment. (KIT Scientific Reports ; 7542)

The sequence of a postulated core melt down accident in the reactor pressure vessel (RPV) of a pressurised water reactor (PWR) involves a large number of complex physical and chemical phenomena. The main objective of the LIVE program is to study the core melt phe-nomena during the late phase of core melt progression in the RPV both experimentally in large-scale 3D geometry in supporting separate-effects tests and analytically using CFD codes in order to provide a reasonable estimate of the remaining uncertainty band under the aspect of safety assessment. The main objective of the LIVE-L3A experiment was to investigate the behaviour of the mol-ten pool and the formation of the crust at the melt/vessel wall interface influenced by the melt relocation position and initial cooling conditions. The test conditions in the LIVE- L3A test were similar to the LIVE-L3 test except the initial cooling conditions. In both tests the melt was poured near to the vessel wall. In the LIVE-L3 test the vessel was initially cooled by air and then by water; in the LIVE-L3A test the vessel was cooled by water already at the start of the experiment. The information obtained in the test includes horizontal and vertical heat flux distribution through the RPV wall, crust growth velocity and dependence of the crust properties on the crust growth velocity and cooling conditions. Supporting post-test analysis contributes to the characterization of solidification processes of binary non-eutectic melts. The results of the LIVE-L3 and LIVE-L3A tests are compared in order to characterize the impact of transient cooling condition on the crust solidification characteristics and melt pool behaviour including interface temperature, time to reach thermal hydraulic steady-state and the steady-state heat flux distribution. The report summarizes the objectives of the LIVE program and presents the main results obtained in the LIVE-L3A test compared to the LIVE-L3 test