On the Preparation of Pure States in Resonant Microcavities

We consider the time evolution of the radiation field (R) and a two-level atom (A) in a resonant microcavity in terms of the Jaynes-Cummings model with an initial general pure quantum state for the radiation field. It is then shown, using the Cauchy-Schwarz inequality and also a Poisson resummation technique, that {\it perfect} coherence of the atom can in general never be achieved. The atom and the radiation field are, however, to a good approximation in a pure state $|\psi >_A\otimes|\psi >_R$ in the middle of what has been traditionally called the ``collapse region'', independent of the initial state of the atoms, provided that the initial pure state of the radiation field has a photon number probability distribution which is sufficiently peaked and phase differences that do not vary significantly around this peak. An approximative analytic expression for the quantity \Tr[\rho^2_{A}(t)], where $\rho_{A}(t)$ is the reduced density matrix for the atom, is derived. We also show that under quite general circumstances an initial entangled pure state will be disentangled to the pure state $|\psi >_{A\otimes R}$.Comment: 14 pages and 3 figure

Complementarity and uncertainty relations for matter wave interferometry

We establish a rigorous quantitative connection between (i) the interferometric duality relation for which-way information and fringe visibility and (ii) Heisenberg's uncertainty relation for position and modular momentum. We apply our theory to atom interferometry, wherein spontaneously emitted photons provide which way information, and unambiguously resolve the challenge posed by the metamaterial `perfect lens' to complementarity and to the Heisenberg-Bohr interpretation of the Heisenberg microscope thought experiment.Comment: nine pages, five figure

Ten Simple Rules for Reproducible Research in Jupyter Notebooks

Reproducibility of computational studies is a hallmark of scientific methodology. It enables researchers to build with confidence on the methods and findings of others, reuse and extend computational pipelines, and thereby drive scientific progress. Since many experimental studies rely on computational analyses, biologists need guidance on how to set up and document reproducible data analyses or simulations. In this paper, we address several questions about reproducibility. For example, what are the technical and non-technical barriers to reproducible computational studies? What opportunities and challenges do computational notebooks offer to overcome some of these barriers? What tools are available and how can they be used effectively? We have developed a set of rules to serve as a guide to scientists with a specific focus on computational notebook systems, such as Jupyter Notebooks, which have become a tool of choice for many applications. Notebooks combine detailed workflows with narrative text and visualization of results. Combined with software repositories and open source licensing, notebooks are powerful tools for transparent, collaborative, reproducible, and reusable data analyses

Endocarditis with aortic root pseudoaneurysm rupture

We report a case of aortic valve endocarditis complicated by aortic root pseudoaneurysm and rupture. (Cardiol J 2007; 14: 202-204

The COVID-19 pandemic and associated inequities in acute myocardial infarction treatment and outcomes

IMPORTANCE: The COVID-19 pandemic disrupted usual care for emergent conditions, such as acute myocardial infarction (AMI). Understanding whether Black and Hispanic individuals experiencing AMI had greater increases in poor outcomes compared with White individuals during the pandemic has important equity implications. OBJECTIVE: To investigate whether the COVID-19 pandemic was associated with increased disparities in treatment and outcomes among Medicare patients hospitalized with AMI. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used Medicare data for patients hospitalized with AMI between January 2016 and November 2020. Patients were categorized as Hispanic, non-Hispanic Black, and non-Hispanic White. The association between race and ethnicity and outcomes as a function of the proportion of hospitalized patients with COVID-19 was evaluated using interrupted time series. Data were analyzed from October 2022 to June 2023. EXPOSURE: The main exposure was a hospital\u27s proportion of hospitalized patients with COVID-19 on a weekly basis as a proxy for care disruption during the pandemic. MAIN OUTCOMES AND MEASURES: Revascularization, 30-day mortality, 30-day readmission, and nonhome discharges. RESULTS: A total of 1 319 273 admissions for AMI (579 817 females [44.0%]; 122 972 Black [9.3%], 117 668 Hispanic [8.9%], and 1 078 633 White [81.8%]; mean [SD] age, 77 [8.4] years) were included. For patients with non-ST segment elevation MI (NSTEMI) overall, the adjusted odds of mortality and nonhome discharges increased by 51% (adjusted odds ratio [aOR], 1.51; 95% CI, 1.29-1.76; P \u3c .001) and 32% (aOR, 1.32; 95% CI, 1.15-1.52; P \u3c .001), respectively, and the odds of revascularization decreased by 27% (aOR, 0.73; 95% CI, 0.64-0.83; P \u3c .001) among patients hospitalized during weeks with a high hospital COVID-19 burden (\u3e30%) vs patients hospitalized prior to the pandemic. Black individuals with NSTEMI experienced a clinically insignificant 7% greater increase in the odds of mortality (aOR, 1.07; 95% CI, 1.00-1.15; P = .04) for each 10% increase in the COVID-19 hospital burden but no increases in readmissions or nonhome discharges or reductions in revascularization rates compared with White individuals. There were no differential increases in adverse outcomes among Hispanic compared with White patients with NSTEMI based on hospital COVID-19 burden. Increases in hospital COVID-19 burden were not associated with changes in outcomes or the use of revascularization in STEMI overall or by racial or ethnic group. CONCLUSIONS AND RELEVANCE: This study found that while hospital COVID-19 burden was associated with worse treatment and outcomes for NSTEMI, race and ethnicity-associated inequities did not increase significantly during the pandemic. These findings suggest the need for additional efforts to mitigate outcomes associated with the COVID-19 pandemic for patients admitted with AMI when the hospital COVID-19 burden is substantially increased

Single atom quantum walk with 1D optical superlattices

A proposal for the implementation of quantum walks using cold atom technology is presented. It consists of one atom trapped in time varying optical superlattices. The required elements are presented in detail including the preparation procedure, the manipulation required for the quantum walk evolution and the final measurement. These procedures can be, in principle, implemented with present technology.Comment: 6 pages, 7 figure

Capability presence in the newly internationalizing firm

We investigate the enablers of early internationalization of the firm. We posit that for firms to internationalize early in their lifecycles, sets of capabilities must be present at the firm’s formative stage and that these capabilities build upon routines that the founders bring into the new firm. These capabilities are aligned to establish a platform for internationalization unencumbered by the administrative heritage often observed in well-established firms. We model this phenomenon, testing it in a cross-national setting of early internationalizing firms in Australia and the United States. To do so, we draw upon a dynamic capabilities framing, conceptualizing and measuring the dynamic capabilities that founders apply in their early internationalization activities