Scalable Ellipsoidal Classification for Bipartite Quantum States

The Separability Problem is approached from the perspective of Ellipsoidal Classification. A Density Operator of dimension N can be represented as a vector in a real vector space of dimension $N^{2}- 1$, whose components are the projections of the matrix onto some selected basis. We suggest a method to test separability, based on successive optimization programs. First, we find the Minimum Volume Covering Ellipsoid that encloses a particular set of properly vectorized bipartite separable states, and then we compute the Euclidean distance of an arbitrary vectorized bipartite Density Operator to this ellipsoid. If the vectorized Density Operator falls inside the ellipsoid, it is regarded as separable, otherwise it will be taken as entangled. Our method is scalable and can be implemented straightforwardly in any desired dimension. Moreover, we show that it allows for detection of Bound Entangled StatesComment: 8 pages, 5 figures, 3 tables. Revised version, to appear in Physical Review

Characterization of highly-oriented ferroelectric Pb_xBa_(1-x)TiO_3

Pb_xBa_(1-x)TiO_3 (0.2 ≾ x ≾ 1) thin films were deposited on single-crystal MgO as well as amorphous Si_3N_4/Si substrates using biaxially textured MgO buffer templates, grown by ion beam-assisted deposition (IBAD). The ferroelectric films were stoichiometric and highly oriented, with only (001) and (100) orientations evident in x-ray diffraction (XRD) scans. Films on biaxially textured templates had smaller grains (60 nm average) than those deposited on single-crystal MgO (300 nm average). Electron backscatter diffraction (EBSD) has been used to study the microtexture on both types of substrates and the results were consistent with x-ray pole figures and transmission electron microscopy (TEM) micrographs that indicated the presence of 90° domain boundaries, twins, in films deposited on single-crystal MgO substrates. In contrast, films on biaxially textured substrates consisted of small single-domain grains that were either c or a oriented. The surface-sensitive EBSD technique was used to measure the tetragonal tilt angle as well as in-plane and out-of-plane texture. High-temperature x-ray diffraction (HTXRD) of films with 90° domain walls indicated large changes, as much as 60%, in the c and a domain fractions with temperature, while such changes were not observed for Pb_xBa_(1-x)TiO_3 (PBT) films on biaxially textured MgO/Si_3N_4/Si substrates, which lacked 90° domain boundaries

PAH in the laboratory and interstellar space

The theory that polycyclic aromatic hydrocarbons (PAHs) are a constituent of the interstellar medium, and a source of the IR emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3 microns is being studied using PAH containing acid insoluble residue of the Orgueil CI meteorite and coal tar. FTIR spectra of Orgueil PAH material that has undergone thermal treatment, and a solvent insoluble fraction of coal tar that has been exposed to hydrogen plasma are presented. The UV excided luminescence spectrum of a solvent soluble coal tar film is also shown. Comparison of the lab measurements with observations appears to support the interstellar PAH theory, and shows the process of dehydrogenation expected to take place in the interstellar medium

Metrics that matter for assessing the ocean biological carbon pump

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Buesseler, K. O., Boyd, P. W., Black, E. E., & Siegel, D. A. Metrics that matter for assessing the ocean biological carbon pump. Proceedings of the National Academy of Sciences of the United States of America, (2020): 201918114, doi: 10.1073/pnas.1918114117.The biological carbon pump (BCP) comprises wide-ranging processes that set carbon supply, consumption, and storage in the oceans’ interior. It is becoming increasingly evident that small changes in the efficiency of the BCP can significantly alter ocean carbon sequestration and, thus, atmospheric CO2 and climate, as well as the functioning of midwater ecosystems. Earth system models, including those used by the United Nation’s Intergovernmental Panel on Climate Change, most often assess POC (particulate organic carbon) flux into the ocean interior at a fixed reference depth. The extrapolation of these fluxes to other depths, which defines the BCP efficiencies, is often executed using an idealized and empirically based flux-vs.-depth relationship, often referred to as the “Martin curve.” We use a new compilation of POC fluxes in the upper ocean to reveal very different patterns in BCP efficiencies depending upon whether the fluxes are assessed at a fixed reference depth or relative to the depth of the sunlit euphotic zone (Ez). We find that the fixed-depth approach underestimates BCP efficiencies when the Ez is shallow, and vice versa. This adjustment alters regional assessments of BCP efficiencies as well as global carbon budgets and the interpretation of prior BCP studies. With several international studies recently underway to study the ocean BCP, there are new and unique opportunities to improve our understanding of the mechanistic controls on BCP efficiencies. However, we will only be able to compare results between studies if we use a common set of Ez-based metrics.We thank the many scientists whose ideas and contributions over the years are the foundation of this paper. This includes A. Martin, who led the organization of the BIARRITZ group (now JETZON) workshop in July 2019, discussions at which helped to motivate this article. We thank D. Karl for pointing us in the right direction for this paper format at PNAS and two thoughtful reviewers who through their comments helped to improve this manuscript. Support for writing this piece is acknowledged from several sources, including the Woods Hole Oceanographic Institution’s Ocean Twilight Zone project (K.O.B.); NASA as part of the EXport Processes in the global Ocean from RemoTe Sensing (EXPORTS) program (K.O.B. and D.A.S.). E.E.B. was supported by a postdoctoral fellowship through the Ocean Frontier Institute at Dalhousie University. P.W.B. was supported by the Australian Research Council through a Laureate (FL160100131)

Metazoan Parasites of the Muskrat, Ondatra Zibethica Cinnamominus, From the English Coulee Grand Forks County, North Dakota

During the fall of 1966 and the spring of 1967, 55 muskrats were trapped along the reaches of the English Coulee, Grand Forks County, North Dakota. These muskrats were necropsied and all ectoparasites and endoparasites collected. The parasites were stained and identified and the number of worms counted to discern the parasite burden. Eight species of parasites were found. The only ectoparasite encountered was Laelaps multispinosus (89.09 per cent incidence). Four species of trematodes were identified as Echinostoma revolutum (34.54 per cent), Quinqueserialis quinqueserialis (47.27 per cent), Notocotylus urbanensis (41.81 per cent), and Plagiorchis proximus (14.54 per cent). Two species of cestodes were found. These were Hymenolepis evaginata (3.63 per cent) and the larval stage of Hydatigera taeniaeformis (16.36 per cent). Only one specimen of a nematode was found. This was Trichuris opaca (1.81 per cent). It was concluded that the worm burden was not sufficient to cause disease, and no obvious pathology was found in any of the muskrats examined

Ion bombardment experiments suggesting an origin for organic particles in pre-cometary and cometary ices

During the Giotto and Vega encounters with Comet Halley both organic particles called CHON and energetic ions were detected. The acceleration of ions to hundreds of keV in the vicinity of the bow shock and near the nucleus may be a demonstration of a situation occurring in the early solar system (perhaps during the T Tauri stage) that led to the formation of organic particles only now released. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, frozen gases were bombarded at 10 K with 175 keV protons with the result that fluffy solid material remains after sublimation of the ice. Initial experiments were carried out with a gas mixture in parts of 170 carbon monoxide, 170 argon, 25 water, 20 nitrogen, and 15 methane formulated to reflect an interstellar composition in experiments involving the freezing out of the products of a plasma. The plasma experiments resulted in a varnish-like film residue that exhibited luminescence when excited with ultraviolet radiation, while the ion bombardment created particulate material that was not luminescent

Disputing Limited Liability

This project presents six years of hand-collected federal district court data to analyze the first representative sample of veil piercing litigation. Our method identifies veil piercing complaints through Westlaw\u27s trial pleadings database and codes each case through a detailed examination of PACER records. We test a variety of hypotheses to understand how such litigations are resolved. We find that plaintiffs succeed quite often in veil piercing litigation, if success is defined as winning on motions that do not terminate a case. A variety of legal and extra-legal factors predict such interstitial veil piercing successes. Voluntary creditor causes of action promote veil piercing; LLCs are in very limited circumstances better insulated from veil piercing claims than corporations; undercapitalization is strongly associated with success while conclusory grounds like façade and sham are not; and defendants\u27 legal sophistication is predictive of plaintiff failure. Extra-legal factors play a more striking and counterintuitive role. Plaintiffs suing companies with few employees are much more likely to win veil piercing motions, and obtain relief in cases, than plaintiffs suing companies employing many workers. This results holds even when controlling for legally-relevant variables. Contrary to both theory and previous empirical work, we also find that judicial liberalism is inversely related to the likelihood of plaintiff success. Our results call into question existing normative and descriptive approaches to the disputation of limited liability and contribute to more general scholarship about selection effects and judicial behavior. They do not provide any easy answers to the question of what defendants can do to insulate themselves from veil piercing. Our analysis suggests: Very little, apart from being very big

Litigating Toward Settlement

Civil litigation typically ends when the parties compromise. While existing theories of settlement primarily focus on information exchange, we instead examine how motion practice, especially non-discovery motions, can substantially shape parties’ knowledge about their cases and thereby influence the timing of settlement. Using docket-level federal district court data, we find a number of strong effects regarding how motions can influence this process, including that the filing of a motion significantly speeds case settlement, that granted motions are more immediately critical to settlement timing than motions denied, and that plaintiff victories have a stronger effect than defendant victories. These results provide a uniquely detailed look at the mechanism of compromise via information exchange and motion practice in litigation while simultaneously yielding evidence that this effect goes well beyond the traditionally studied discovery process