Spinor Dynamics-Driven Formation of a Dual-Beam Atom Laser

We demonstrate a novel dual-beam atom laser formed by outcoupling oppositely polarized components of an F=1 spinor Bose-Einstein condensate whose Zeeman sublevel populations have been coherently evolved through spin dynamics. The condensate is formed through all-optical means using a single-beam running-wave dipole trap. We create a condensate in the field-insensitive $m_F=0$ state, and drive coherent spin-mixing evolution through adiabatic compression of the initially weak trap. Such dual beams, number-correlated through the angular momentum-conserving reaction $2m_0\leftrightharpoons m_{+1}+m_{-1}$, have been proposed as tools to explore entanglement and squeezing in Bose-Einstein condensates, and have potential use in precision phase measurements.Comment: 4 pages, 4 figure

Synthetic clock transitions via continuous dynamical decoupling

Decoherence of quantum systems due to uncontrolled fluctuations of the environment presents fundamental obstacles in quantum science. `Clock' transitions which are insensitive to such fluctuations are used to improve coherence, however, they are not present in all systems or for arbitrary system parameters. Here, we create a trio of synthetic clock transitions using continuous dynamical decoupling in a spin-1 Bose-Einstein condensate in which we observe a reduction of sensitivity to magnetic field noise of up to four orders of magnitude; this work complements the parallel work by Anderson et al. (submitted, 2017). In addition, using a concatenated scheme, we demonstrate suppression of sensitivity to fluctuations in our control fields. These field-insensitive states represent an ideal foundation for the next generation of cold atom experiments focused on fragile many-body phases relevant to quantum magnetism, artificial gauge fields, and topological matter.Comment: 8 pages, 4 figures, Supplemental material

Differential Light Shift Cancellation in a Magnetic-Field-Insensitive Transition of 87^{87}Rb

We demonstrate near-complete cancellation of the differential light shift of a two-photon magnetic-field-insensitive microwave hyperfine (clock) transition in $^{87}$Rb atoms trapped in an optical lattice. Up to $95(2)$ of the differential light shift is canceled while maintaining magnetic-field insensitivity. This technique should have applications in quantum information and frequency metrology.Comment: 5 pages, 4 figure

Repeated Measurements with Minimally Destructive Partial-Transfer Absorption Imaging

We demonstrate partial-transfer absorption imaging as a technique for repeatedly imaging an ultracold atomic ensemble with minimal perturbation. We prepare an atomic cloud in a state that is dark to the imaging light. We then use a microwave pulse to coherently transfer a small fraction of the ensemble to a bright state, which we image using in situ absorption imaging. The amplitude or duration of the microwave pulse controls the fractional transfer from the dark to the bright state. For small transfer fractions, we can image the atomic cloud up to 50 times before it is depleted. As a sample application, we repeatedly image an atomic cloud oscillating in a dipole trap to measure the trap frequency

Pursuing High Performance in Rural Health Care

In 2001, the Institute of Medicine (IOM) called for transformation of the United States health care system to make it safe, effective, patient-centered, timely, efficient, and equitable.1 The journey toward these six aims in public policy and the private sector is underway, but fundamental challenges detailed by the IOM remain. Patients are injured at alarming rates, wide variation in care exists across geographies, patients complain of insensitive and/or inaccessible health care providers, health care costs are nearly twice that in other developed countries, and nearly 50 million Americans lack health insurance. As a result, our health care is often fragmented, uncoordinated, and excessively costly. In fact, the United States health care system has been called a “non-system.” The rural health care landscape is additionally challenged by independent and autonomous providers often struggling to survive financially, burdensome geographic separations in health care services, and incompatible information technologies. As a result, resources are wasted, patients are harmed, and rural communities are neglected. Despite persistent rural challenges, public policies during the past 30 years have helped build and stabilize rural health care services. New payments have increased revenue for physicians practicing in shortage areas, rural hospitals certified as Critical Access Hospitals (very small hospitals in isolated places), Sole Community Hospitals (larger hospitals also in isolated areas), and Rural Health Clinics (primary care clinics staffed by nurse practitioners and/or physician assistants). New programs continue to provide technical assistance and grants to rural hospitals (Medicare Rural Hospital Flexibility Program), fund installation of telemedicine equipment, and promote rural health professions education. These successes have required political capital and developmental resources to support a system that delivers discrete and uncoordinated health care services, provided by specific professionals and institutions, each paid on a per-service basis. Yet, progressive work by the Institute of Medicine (especially the Rural Health Committee document Quality Through Collaboration: The Future of Rural Health Care), the Commonwealth Commission on a High Performance Healthcare System, and other organizations suggest more effective strategies to improve and sustain the health of rural people..

Shell potentials for microgravity Bose-Einstein condensates

Extending the understanding of Bose-Einstein condensate (BEC) physics to new geometries and topologies has a long and varied history in ultracold atomic physics. One such new geometry is that of a bubble, where a condensate would be confined to the surface of an ellipsoidal shell. Study of this geometry would give insight into new collective modes, self-interference effects, topology-dependent vortex behavior, dimensionality crossovers from thick to thin shells, and the properties of condensates pushed into the ultradilute limit. Here we discuss a proposal to implement a realistic experimental framework for generating shell-geometry BEC using radiofrequency dressing of magnetically-trapped samples. Such a tantalizing state of matter is inaccessible terrestrially due to the distorting effect of gravity on experimentally-feasible shell potentials. The debut of an orbital BEC machine (NASA Cold Atom Laboratory, aboard the International Space Station) has enabled the operation of quantum-gas experiments in a regime of perpetual freefall, and thus has permitted the planning of microgravity shell-geometry BEC experiments. We discuss specific experimental configurations, applicable inhomogeneities and other experimental challenges, and outline potential experiments.Comment: 6 pages, 3 figure

Pursuing High Performance in Rural Health Care

Rural Futures Lab Foundation Papers are intended to present current thinking on the economic drivers and opportunities that will shape the future of rural America. They provide the foundation upon which it will be possible to answer the question that drives the Lab’s work—What has to happen today in order to achieve positive rural outcomes tomorrow

Atoms in a radiofrequency-dressed optical lattice

We load cold atoms into an optical lattice dramatically reshaped by radiofrequency (rf) coupling of state-dependent lattice potentials. This rf dressing changes the unit cell of the lattice at a subwavelength scale, such that its curvature and topology departs strongly from that of a simple sinusoidal lattice potential. Radiofrequency dressing has previously been performed at length scales from mm to tens of microns, but not at the single-optical-wavelength scale. At this length scale significant coupling between adiabatic potentials leads to nonadiabatic transitions, which we measure as a function of lattice depth and dressing frequency and amplitude. We also investigate the dressing by measuring changes in the momentum distribution of the dressed states.Comment: 5 pages, 4 figure

Observation of ultracold atomic bubbles in orbital microgravity

Substantial leaps in the understanding of quantum systems have been driven by exploring geometry, topology, dimensionality and interactions in ultracold atomic ensembles1–6. A system where atoms evolve while confined on an ellipsoidal surface represents a heretofore unexplored geometry and topology. Realizing an ultracold bubble—potentially Bose–Einstein condensed—relates to areas of interest including quantized-vortex flow constrained to a closed surface topology, collective modes and self-interference via bubble expansion7–17. Large ultracold bubbles, created by inflating smaller condensates, directly tie into Hubble-analogue expansion physics18–20. Here we report observations from the NASA Cold Atom Lab21 facility onboard the International Space Station of bubbles of ultracold atoms created using a radiofrequency-dressing protocol. We observe bubble configurations of varying size and initial temperature, and explore bubble thermodynamics, demonstrating substantial cooling associated with inflation. We achieve partial coverings of bubble traps greater than one millimetre in size with ultracold films of inferred few-micrometre thickness, and we observe the dynamics of shell structures projected into free-evolving harmonic confinement. The observations are among the first measurements made with ultracold atoms in space, using perpetual freefall to explore quantum systems that are prohibitively difficult to create on Earth. This work heralds future studies (in orbital microgravity) of the Bose–Einstein condensed bubble, the character of its excitations and the role of topology in its evolution

Advancing the Transition to a High Performance Rural Health System

There are growing concerns about the current and future state of rural health. Despite decades of policy efforts to stabilize rural health systems through a range of policies and loan and grant programs, accelerating rural hospital closures combined with rapid changes in private and public payment strategies have created widespread concern that these solutions are inadequate for addressing current rural health challenges. The rural health system of today is the product of legacy policies and programs that often do not “fit” current local needs. Misaligned incentives undermine high-value and efficient care delivery. While there are limitations related to scalability in rural health system development, rural communities do have enormous potential to achieve the objectives of a high performance rural health system. This brief (and a companion paper at http://www.rupri.org/areas-of-work/health-policy/) discusses strategies and options for creating a pathway to a transformed, high performing rural health system