Spectral properties of finite laser-driven lattices of ultracold Rydberg atoms

We investigate the spectral properties of a finite laser-driven lattice of ultracold Rydberg atoms exploiting the dipole blockade effect in the frozen Rydberg gas regime. Uniform one-dimensional lattices as well as lattices with variable spacings are considered. In the case of a weak laser coupling, we find a multitude of many-body Rydberg states with well-defined excitation properties which are adiabatically accessible starting from the ground state. A comprehensive analysis of the degeneracies of the spectrum as well as of the single and pair excitations numbers of the eigenstates is performed. In the strong laser regime, analytical solutions for the pseudo-fermionic eigenmodes are derived. Perturbative energy corrections for this approximative approach are provided.Comment: 17 pages, 12 figure

Rydberg-atom trajectories in a ponderomotive optical lattice

Using semiclassical simulations, we investigate the trajectories and the microwave spectra of Rydberg atoms excited in a ponderomotive optical lattice. We relate distinct features found in the microwave spectra to characteristic types of trajectory. Several methods are presented that are designed to greatly improve the trapping efficiency of the lattice and to generalize the trapping from one to three dimensions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85435/1/njp10_11_113036.pd

Manipulation and Detection of a Trapped Yb+ Ion Hyperfine Qubit

We demonstrate the use of trapped ytterbium ions as quantum bits for quantum information processing. We implement fast, efficient state preparation and state detection of the first-order magnetic field-insensitive hyperfine levels of 171Yb+, with a measured coherence time of 2.5 seconds. The high efficiency and high fidelity of these operations is accomplished through the stabilization and frequency modulation of relevant laser sources.Comment: 10 pages, 9 figures, 1 tabl

Compliance with a New York State 2010 HIV Testing Law: Is There Racial/Ethnic Bias in HIV Testing? Experience of Monroe County, New York, 2012

Background: While routine HIV testing in the general population is a national recommendation, actual practice may vary. Purpose: To determine risk factors associated with HIV testing after the adoption of a New York State law in 2010 mandating that healthcare providers offer HIV testing in all clinical settings. Methods.: Survey data from Monroe County, New York, were collected in 2012 for adults aged 18-64 years and analyzed in 2014. Logistic regression was used to identify risk factors independently associated with HIV testing and high-risk behavior. Results: Among adults aged 18-34 years, fewer Whites were offered HIV testing in the past year by their doctors compared with Blacks (34% vs 64%) despite having similar rates of any HIV high-risk behavior (20% overall). For adults aged 35-64 years, fewer Whites than Blacks were ever tested for HIV (42% vs 71%), offered HIV testing in past year (17% vs 40%), and reported any HIV high-risk behavior (3% vs 13%). Latinos showed intermediate levels. With logistic regression analysis, ever tested for HIV was independently associated with only race/ethnicity; offered HIV testing in the past year was associated with females, Blacks and Latinos, aged 18-34 years, and having a routine health checkup in past year; any HIV high-risk behavior was associated with only younger age. Conclusions: To improve HIV testing rates as well as compliance with state laws and national guidelines, targeted efforts should be considered that improve perceptions of risk and emphasize the value of routine HIV screening, including those directed at white adults and their health care providers

A crossed vortex bottle beam trap for single-atom qubits

We demonstrate trapping and quantum state control of single Cesium atoms in a 532 nm wavelength bottle beam trap. The three dimensional trap is formed by crossing two unit charge vortex beams. Single atoms are loaded with 50% probability directly from a magneto-optical trap. We achieve a trapping lifetime of up to 6 s, and demonstrate fast Rabi oscillations with a coherence time of $T_2\sim 43 \pm 9\rm ms$.Comment: 5 figures, minor edits to text and figures, to appear opt. let

The impact of a high‐definition multileaf collimator for spine SBRT

PurposeAdvanced radiotherapy delivery systems designed for high‐dose, high‐precision treatments often come equipped with high‐definition multi‐leaf collimators (HD‐MLC) aimed at more finely shaping radiation dose to the target. In this work, we study the effect of a high definition MLC on spine stereotactic body radiation therapy (SBRT) treatment plan quality and plan deliverability.Methods and MaterialsSeventeen spine SBRT cases were planned with VMAT using a standard definition MLC (M120), HD‐MLC, and HD‐MLC with an added objective to reduce monitor units (MU). M120 plans were converted into plans deliverable on an HD‐MLC using in‐house software. Plan quality and plan deliverability as measured by portal dosimetry were compared among the three types of plans.ResultsOnly minor differences were noted in plan quality between the M120 and HD‐MLC plans. Plans generated with the HD‐MLC tended to have better spinal cord sparing (3% reduction in maximum cord dose). HD‐MLC plans on average had 12% more MU and 55% greater modulation complexity as defined by an in‐house metric. HD‐MLC plans also had significantly degraded deliverability. Of the VMAT arcs measured, 94% had lower gamma passing metrics when using the HD‐MLC.ConclusionModest improvements in plan quality were noted when switching from M120 to HD‐MLC at the expense of significantly less accurate deliverability in some cases.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139989/1/acm212197.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139989/2/acm212197_am.pd

Using Smartphone Apps in STD Interviews to Find Sexual Partners

Objectives. Smartphone applications (apps) are increasingly used to facilitate casual sexual relationships, increasing the risk of sexually transmitted diseases (STDs). In STD investigations, traditional contact elicitation methods can be enhanced with smartphone technology during field interviews. Methods. In 2013, the Monroe County Department of Public Health conducted a large, multi-infection STD investigation among men who have sex with men (MSM) using both index case and cluster interviews. When patients indicated meeting sexual partners online, disease intervention specialists (DISs) had access to smartphone apps and were able to elicit partners through access to inboxes and profiles where traditional contact information was lacking. Social network mapping was used to display the extent of the investigation and the impact of access to smartphones on the investigation. Results. A total of 14 index patient interviews and two cluster interviews were conducted; 97 individuals were identified among 117 sexual dyads. On average, eight partners were elicited per interview (range: 1–31). The seven individuals who used apps to find partners had an average of three Internet partners (range: 1–5). Thirty-six individuals either had a new STD (n=7) or were previously known to be HIV-positive (n=29). Of the 117 sexual dyads, 21 (18%) originated either online (n=8) or with a smartphone app (n=13). Of those originating online or with a smartphone app, six (29%) partners were located using the smartphone and two (10%) were notified of their exposure via a website. Three of the new STD/HIV cases were among partners who met online. Conclusion. Smartphone technology used by DISs in the field improved contact elicitation and resulted in successful partner notification and case finding

Toppling statues and making space: prospects for anti-racist cultural activism

Statues have long been recognized as impositions of a particular past that legitimize a power-laden present. Consequently, toppling statues, and engaging with the space they once occupied, opens up the possibility of new and multiple narratives. This article takes this moment of possibility as its starting point. Drawing from nine case studies in five countries, and from thirty-one interviews with cultural activists and other stakeholders, we identify three patterns that emerge in the aftermath of removing statues. First, removing a statue changes the hegemonic narrative of the space it once occupied. Second, stakeholders resist the imposition of a singular new narrative on that space. Third, policymakers and institutions attempt to regulate the space and the narratives it carries. We argue, further, that whilst attempts to impose a new, single narrative on the same site are widely met with obstacles, empty plinths become multivocal sites of memory in their own right