Integrated Atom Detector Based on Field Ionization near Carbon Nanotubes

We demonstrate an atom detector based on field ionization and subsequent ion counting. We make use of field enhancement near tips of carbon nanotubes to reach extreme electrostatic field values of up to 9x10^9 V/m, which ionize ground state rubidium atoms. The detector is based on a carpet of multiwall carbon nanotubes grown on a substrate and used for field ionization, and a channel electron multiplier used for ion counting. We measure the field enhancement at the tips of carbon nanotubes by field emission of electrons. We demonstrate the operation of the field ionization detector by counting atoms from a thermal beam of a rubidium dispenser source. By measuring the ionization rate of rubidium as a function of the applied detector voltage we identify the field ionization distance, which is below a few tens of nanometers in front of nanotube tips. We deduce from the experimental data that field ionization of rubidium near nanotube tips takes place on a time scale faster than 10^(-10)s. This property is particularly interesting for the development of fast atom detectors suitable for measuring correlations in ultracold quantum gases. We also describe an application of the detector as partial pressure gauge.Comment: 7 pages, 8 figure

Experimental investigation of the use of sharp edges for the production of positive ions in field-ionization mass spectrometry

Various commercial razor blades have been tested for field ionization performance and compared with edges prepared electrochemically from platinum and tungsten foils. The results are correlated with data obtained from electron micrographs of the various edges. It is concluded that tungsten edges offer the best compromise between field ionization efficiency and durability of the edge

Atmospheric Neutrinos

The results of experiments on atmospheric neutrinos are summarized, with the important exception of Superkamiokande. The main emphasis is given to the Soudan-2 and MACRO experiments. Both experiments observe atmospheric neutrino anomalies in agreement with nu_mu-->> nu_tau oscillations with maximum mixing. The nu_mu-->> nu_sterile oscillation is disfavored by the MACRO experiment.Comment: To be published in the proceedings of TAUP99 Conference College de France - Paris 6-10 September 1999 11 pages 12 figure

Single Search with SOLR or what to do when everything goes to &@#$

All libraries periodically debut new technologies: a website redesign, new content management systems, subscribing to new databases, etc. Often these new technologies are welcomed and work well, but sometimes they fail to meet expectations...and occasionally they fail in a spectacular manner. Many libraries offer web-based search interfaces to digital resources, and current trends in search technologies are to index multiple material types in one platform and to provide a simple search box and a way for users to filter the results. The Minnesota Historical Society combined the separate search interfaces for some of our most popular records into a single, SOLR-based search platform. In the summer of 2015, the new search debuted to uniformly poor reviews from our users, and in the fall MNHS held a series of focus groups to get input on designing a new search. In this session, we will be sharing our experiences in the aftermath of this launch, including: Crisis management systems and styles Creating and using tools to ameliorate searchers\u27 frustration and to make a bad system usable Moving out of crisis mode: going forward with thought-out solutions and creating positive incremental changes Setting up and gathering feedback to improve the system Focus groups: what we learned about how users really prefer to search for historical research materials and genealogical records Best practices: proposed data points for building web interfaces to search across data silos and heterogeneous material types. Learning objectives: 1. Recognize technology projects with a potential for a bad debut and pre-plan for mitigating fallout. 2. Identify a set of concrete tools for handling the public side of tech crises. 3. Understand how to incorporate user input into search design as well as metadata issues to consider when incorporating vital records into a single search

Quantum measurements in fundamental physics: a user's manual

We give a systematic theoretical treatment of linear quantum detectors used in modern high energy physics experiments, including dark matter cavity haloscopes, gravitational wave detectors, and impulsive mechanical sensors. We show how to derive the coupling of signals of interest to these devices, and how to calculate noise spectra, signal-to-noise ratios, and detection sensitivities. We emphasize the role of quantum vacuum and thermal noise in these systems. Finally, we review ways in which advanced quantum techniques -- squeezing, non-demolition measurements, and entanglement -- can be or currently are used to enhance these searches.Comment: 50 pages, many figures. Corrections and suggestions for new material are welcom

Review of nifedipine GITS in the treatment of high risk patients with coronary artery disease and hypertension

Nifedipine is a dihydropyridine calcium-channel blocker (CCB) introduced approximately 30 years ago for the prophylaxis of angina symptoms, and then later utilized as an anti-hypertensive agent. In the 1990s, several meta-analyses and a case-control study were published which raised concern regarding increased mortality and increased risk for myocardial infarction with short-acting nifedipine. Further evaluation of these meta-analyses and case control study underscores some important limitations and the need to further elucidate the role of this class of medications in high-risk patients. Until 2000, there was a paucity of data on the long-term effects as well as the long-term outcomes of CCBs in the treatment of stable coronary disease or in patients with manifestations of the disease such as hypertension or angina. While it has been well established that nifedipine and other dihydropyridines lower blood pressure and improve symptoms of angina, several studies were designed to evaluate the effect of dihydropyridines on “hard” outcomes, specifically cardiovascular and cerebrovascular events. In this review, we describe the clinical studies evaluating the use of nifedipine when compared to placebo as well as other anti-hypertensive therapies in an attempt to identify the most appropriate place in therapy for this class of medications and to further clarify its utilization in high-risk patients

Computable and operationally meaningful multipartite entanglement measures

Multipartite entanglement is an essential resource for quantum communication, quantum computing, quantum sensing, and quantum networks. The utility of a quantum state, $|\psi\rangle$, for these applications is often directly related to the degree or type of entanglement present in $|\psi\rangle$. Therefore, efficiently quantifying and characterizing multipartite entanglement is of paramount importance. In this work, we introduce a family of multipartite entanglement measures, called Concentratable Entanglements. Several well-known entanglement measures are recovered as special cases of our family of measures, and hence we provide a general framework for quantifying multipartite entanglement. We prove that the entire family does not increase, on average, under Local Operations and Classical Communications. We also provide an operational meaning for these measures in terms of probabilistic concentration of entanglement into Bell pairs. Finally, we show that these quantities can be efficiently estimated on a quantum computer by implementing a parallelized SWAP test, opening up a research direction for measuring multipartite entanglement on quantum devices.Comment: 5+15 pages. 3+4 figures. Updated to published versio

Documenting Flyover Land

Fueled by images of flat plains, small towns, and harsh winters, the midwestern United States is often perceived as nothing more than “flyover land” by outsiders. Though the political climate of the last several years has brought increased attention to the region, it has also reinforced the notion that the Midwest’s small towns and industries have been forgotten. Featuring speakers from Minnesota, Kansas, Iowa, and Missouri, this session will explore the relationship between archives and rural life in the Midwest. Together, the speakers will address how archivists can capture and share stories that challenge the notion that the Midwest is nothing more than “flyover land.” Mark Anderson will explore the connection between documenting rural life in the Midwest and digital collections curation. Jackie Beckey will talk about the availability of resources related to various aspects of rural life in the Midwest, including resources available at her institution that document radical rural midwestern politics, as well as the lack of available documentation for American Indian genealogy research. Volodymyr Chumachenko will present on the ways his institution has done outreach work around records documenting agricultural communities and ranching in Kansas. Roxanne Dunn will talk about overcoming challenges to acquire a collection about a farmer’s rights, which had a direct effect on federal bankruptcy code. Carissa Hansen will speak about her efforts to promote and work with members of a rural community in Minnesota to build awareness for literary manuscript collections that capture small-town life in ways that are often unexpected

Multipartite entanglement measures via Bell basis measurements

We show how to estimate a broad class of multipartite entanglement measures from Bell basis measurement data. In addition to lowering the experimental requirements relative to previously known methods of estimating these measures, our proposed scheme also enables a simpler analysis of the number of measurement repetitions required to achieve an $\epsilon$-close approximation of the measures, which we provide for each. We focus our analysis on the recently introduced Concentratable Entanglements [Beckey et al. Phys. Rev. Lett. 127, 140501 (2021)] because many other well-known multipartite entanglement measures are recovered as special cases of this family of measures. We extend the definition of the Concentratable Entanglements to mixed states and show how to construct lower bounds on the mixed state Concentratable Entanglements that can also be estimated using only Bell basis measurement data. Finally, we demonstrate the feasibility of our methods by realistically simulating their implementation on a Rydberg atom quantum computer.Comment: 5+19 pages. 4+3 figure