Observing and braiding topological Majorana modes on programmable quantum simulators

Despite its great promise of fault tolerance, the simplest demonstration of topological quantum computation remains elusive. Majorana modes are the primitive building blocks and their experimental realization on various platforms is yet to be confirmed. This work presents an experimental and theoretical framework for the space-resolved detection and exchange of Majorana modes on programmable (noisy) quantum hardware. We have implemented our framework by performing a series of measurements on a driven Ising-type quantum spin model with tunable interactions, which confirm the existence of the topological Majorana modes and distinguishes them from trivial modes. Lastly, we propose and demonstrate a novel technique for braiding the Majorana modes which results in the correct statistics but decreases the magnitude of the signal. The present work may be seen as the first reliable observation of Majorana modes on existing quantum hardware.Comment: 6 pages (main text)+ 8 pages (supplementary); 4 figure

Entropy-driven order in an array of nanomagnets

Long-range ordering is typically associated with a decrease in entropy. Yet, it can also be driven by increasing entropy in certain special cases. Here we demonstrate that artificial spin-ice arrays of single-domain nanomagnets can be designed to produce such entropy-driven order. We focus on the tetris artificial spin-ice structure, a highly frustrated array geometry with a zero-point Pauling entropy, which is formed by selectively creating regular vacancies on the canonical square ice lattice. We probe thermally active tetris artificial spin ice both experimentally and through simulations, measuring the magnetic moments of the individual nanomagnets. We find two-dimensional magnetic ordering in one subset of these moments, which we demonstrate to be induced by disorder (that is, increased entropy) in another subset of the moments. In contrast with other entropy-driven systems, the discrete degrees of freedom in tetris artificial spin ice are binary and are both designable and directly observable at the microscale, and the entropy of the system is precisely calculable in simulations. This example, in which the system’s interactions and ground-state entropy are well defined, expands the experimental landscape for the study of entropy-driven ordering

COVID-19 vaccine perceptions in the initial phases of US vaccine roll-out: an observational study on reddit.

BACKGROUND: Open online forums like Reddit provide an opportunity to quantitatively examine COVID-19 vaccine perceptions early in the vaccine timeline. We examine COVID-19 misinformation on Reddit following vaccine scientific announcements, in the initial phases of the vaccine timeline. METHODS: We collected all posts on Reddit (reddit.com) from January 1 2020 - December 14 2020 (n=266,840) that contained both COVID-19 and vaccine-related keywords. We used topic modeling to understand changes in word prevalence within topics after the release of vaccine trial data. Social network analysis was also conducted to determine the relationship between Reddit communities (subreddits) that shared COVID-19 vaccine posts, and the movement of posts between subreddits. RESULTS: There was an association between a Pfizer press release reporting 90% efficacy and increased discussion on vaccine misinformation. We observed an association between Johnson and Johnson temporarily halting its vaccine trials and reduced misinformation. We found that information skeptical of vaccination was first posted in a subreddit (r/Coronavirus) which favored accurate information and then reposted in subreddits associated with antivaccine beliefs and conspiracy theories (e.g. conspiracy, NoNewNormal). CONCLUSIONS: Our findings can inform the development of interventions where individuals determine the accuracy of vaccine information, and communications campaigns to improve COVID-19 vaccine perceptions, early in the vaccine timeline. Such efforts can increase individual- and population-level awareness of accurate and scientifically sound information regarding vaccines and thereby improve attitudes about vaccines, especially in the early phases of vaccine roll-out. Further research is needed to understand how social media can contribute to COVID-19 vaccination services

Knowledge and Perception of COVID-19, Prevalence of Pre-Existing Conditions, and Access to Essential Resources and Health Services in Somali IDP Camps

Background: Three million internally displaced Somalis live in overcrowded settlements with weakened infrastructure, insufficient access to WASH facilities, and inaccessible health services.This vulnerable population is especially susceptible to COVID-19, which is expected to have worsened health outcomes and exacerbate existing structural challenges in the implementation of public health measures. This study examines knowledge of COVID-19, self-reported prevalence of preexisting conditions, and access to essential health services among residents of internally displaced persons (IDP) camps in Somalia. Methods: A descriptive, cross-sectional survey design assessing demographics, current health profiles, knowledge and perceptions of COVID-19, and access to resources was used. 401 Somali IDP camp residents completed the survey. Results: Though 77% of respondents reported taking at least one COVID-19 preventative public health measure, respondents reported a severe lack of access to adequate sanitation, an inability to practice social distancing, and nearly universal inability to receive a COVID-19 screening exam. Questions assessing knowledge surrounding COVID-19 prevention and treatment yielded answers of “I don’t know” for roughly 50% of responses. The majority were not familiar with basic information about the virus or confident that they could receive medical services if infected. Those who perceived their health status to be “fair,” as opposed to “good,” showed 5.69 times higher odds of being concerned about contracting COVID-19. Respondents who felt more anxious or nervous and those who introduced one behavioral change to protect against COVID-19 transmission showed 10.16 and 5.20 times increased odds of being concerned about disease contraction, respectively. Conclusion: This study highlights immense gaps in the knowledge and perceptions of COVID-19 and access to treatment and preventative services among individuals living in Somali IDP camps. A massive influx of additional resources is required to adequately address COVID-19 in Somalia, starting with educating those individuals most vulnerable to infection

COVID-19 Vaccine Perceptions on Reddit

BACKGROUND: Open online forums like Reddit provide an opportunity to quantitatively examine COVID-19 vaccine perceptions early in the vaccine timeline. We examine COVID-19 misinformation on Reddit following vaccine scientific announcements, in the initial phases of the vaccine timeline. METHODS: We collected all posts on Reddit (reddit.com) from January 1 2020 - December 14 2020 (n=266,840) that contained both COVID-19 and vaccine-related keywords. We used topic modeling to understand changes in word prevalence within topics after the release of vaccine trial data. Social network analysis was also conducted to determine the relationship between Reddit communities (subreddits) that shared COVID-19 vaccine posts, and the movement of posts between subreddits. RESULTS: There was an association between a Pfizer press release reporting 90% efficacy and increased discussion on vaccine misinformation. We observed an association between Johnson and Johnson temporarily halting its vaccine trials and reduced misinformation. We found that information skeptical of vaccination was first posted in a subreddit (r/Coronavirus) which favored accurate information and then reposted in subreddits associated with antivaccine beliefs and conspiracy theories (e.g. conspiracy, NoNewNormal). CONCLUSIONS: Our findings can inform the development of interventions where individuals determine the accuracy of vaccine information, and communications campaigns to improve COVID-19 vaccine perceptions, early in the vaccine timeline. Such efforts can increase individual- and population-level awareness of accurate and scientifically sound information regarding vaccines and thereby improve attitudes about vaccines, especially in the early phases of vaccine roll-out. Further research is needed to understand how social media can contribute to COVID-19 vaccination services