Bostonia. Volume 2

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Spatial Attention to Social Cues is not a Monolithic Process

Social stimuli are a highly salient source of information, and seem to possess unique qualities that set them apart from other well-known categories. One characteristic is their ability to elicit spatial orienting, whereby directional stimuli like eyegaze and pointing gestures act as exogenous cues that trigger automatic shifts of attention that are difficult to inhibit. This effect has been extended to non-social stimuli, like arrows, leading to some uncertainty regarding whether spatial orienting is specialized for social cues. Using a standard spatial cueing paradigm, we found evidence that both a pointing hand and arrow are effective cues, but that the hand is encoded more quickly, leading to overall faster responses. We then extended the paradigm to include multiple cues in order to evaluate congruent vs. incongruent cues. Our results indicate that faster encoding of the social cue leads to downstream effects on the allocation of attention resulting in faster orientin

Perfect quantum error correction coding in 24 laser pulses

An efficient coding circuit is given for the perfect quantum error correction of a single qubit against arbitrary 1-qubit errors within a 5 qubit code. The circuit presented employs a double `classical' code, i.e., one for bit flips and one for phase shifts. An implementation of this coding circuit on an ion-trap quantum computer is described that requires 26 laser pulses. A further circuit is presented requiring only 24 laser pulses, making it an efficient protection scheme against arbitrary 1-qubit errors. In addition, the performance of two error correction schemes, one based on the quantum Zeno effect and the other using standard methods, is compared. The quantum Zeno error correction scheme is found to fail completely for a model of noise based on phase-diffusion.Comment: Replacement paper: Lost two laser pulses gained one author; added appendix with circuits easily implementable on an ion-trap compute

Scalable background-limited polarization-sensitive detectors for mm-wave applications

We report on the status and development of polarization-sensitive detectors for millimeter-wave applications. The detectors are fabricated on single-crystal silicon, which functions as a low-loss dielectric substrate for the microwave circuitry as well as the supporting membrane for the Transition-Edge Sensor (TES) bolometers. The orthomode transducer (OMT) is realized as a symmetric structure and on-chip filters are employed to define the detection bandwidth. A hybridized integrated enclosure reduces the high-frequency THz mode set that can couple to the TES bolometers. An implementation of the detector architecture at Q-band achieves 90% efficiency in each polarization. The design is scalable in both frequency coverage, 30-300 GHz, and in number of detectors with uniform characteristics. Hence, the detectors are desirable for ground-based or space-borne instruments that require large arrays of efficient background-limited cryogenic detectors.Comment: 7 pages, 3 figures, Presented at SPIE Astronomical Telescopes and Instrumentation 2014: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII. To be published in Proceedings of SPIE Volume 915

Unconditional teleportation of continuous-variable entanglement

We give a protocol and criteria for demonstrating unconditional teleportation of continuous-variable entanglement (i.e., entanglement swapping). The initial entangled states are produced with squeezed light and linear optics. We show that any nonzero entanglement (any nonzero squeezing) in both of two entanglement sources is sufficient for entanglement swapping to occur. In fact, realization of continuous-variable entanglement swapping is possible using only {\it two} single-mode squeezed states.Comment: 4 pages, 2 figures, published version, title change

High-speed metamagnetic resistive switching of FeRh through Joule heating

Due to its proximity to room temperature and demonstrated high degree of temperature tunability, the metamagnetic ordering transition in FeRh is attractive for novel high-performance computing devices seeking to use magnetism as the state variable. We demonstrate electrical control of the transition via Joule heating in FeRh wires. Finite element simulations based on abrupt state transition within each domain result in a globally smooth transition that agrees with the experimental findings and provides insight into the thermodynamics involved. We measure a 150 K decrease in transition temperature with currents up to 60 mA, limited only by the dimensions of the device. The sizeable shift in transition temperature scales with current density and wire length, suggesting the absolute resistance and heat dissipation of the substrate are also important. The FeRh phase change is evaluated by pulsed I-V using a variety of bias conditions. We demonstrate high speed (~ ns) memristor-like behavior and report device performance parameters such as switching speed and power consumption that compare favorably with state-of-the-art phase change memristive technologies.Comment: 35 pages, 9 figure

Multipartite entanglement for continuous variables: A quantum teleportation network

We show that {\it one} single-mode squeezed state distributed among $N$ parties using linear optics suffices to produce a truly $N$-partite entangled state for any nonzero squeezing and arbitrarily many parties. From this $N$-partite entangled state, via quadrature measurements of $N-2$ modes, bipartite entanglement between any two of the $N$ parties can be `distilled', which enables quantum teleportation with an experimentally determinable fidelity better than could be achieved in any classical scheme.Comment: 4 pages, 2 figures, published version, paper shorter, title longe

Racial differences in user experiences and perceived value of electronic symptom monitoring in a cohort of black and white bladder and prostate cancer patients

Purpose: Electronic patient-reported outcomes (ePROs) are increasingly being used for symptom monitoring during routine cancer care, but have rarely been evaluated in diverse patient populations. We assessed ePRO user experiences and perceived value among Black and White cancer patients. Methods: We recruited 30 Black and 49 White bladder and prostate cancer patients from a single institution. Participants reported symptoms using either a web-based or automated telephone interface over 3 months and completed satisfaction surveys and qualitative interviews focused on user experiences and value. Using a narrative mixed methods approach, we evaluated overall and race-specific differences in ePRO user experiences and perceived value. Results: Most participants selected the web-based system, but Blacks were more likely to use the automated telephone-based system than Whites. In satisfaction surveys, Whites more commonly reported ease in understanding and reporting symptoms compared with Blacks. Blacks more often reported that the ePRO system was helpful in facilitating symptom-related discussions with clinicians. During interviews, Blacks described how the ePRO helped them recognize symptoms, while Whites found value in better understanding and tracking symptoms longitudinally. Blacks also expressed preferences for paper-based ePRO options due to perceived ease in better understanding of symptom items. Conclusion: Electronic patient-reported outcomes are perceived as valuable for variable reasons by Black and White cancer populations, with greater perceived value for communicating with clinicians reported among Blacks. To optimize equitable uptake of ePROs, oncology practices should offer several ePRO options (e.g., web-based, phone-based), as well as paper-based options, and consider the e-health literacy needs of patients during implementation