Entanglement universality of two-qubit X-states

We demonstrate that for every two-qubit state there is a X-counterpart, i.e., a corresponding two-qubit X-state of same spectrum and entanglement, as measured by concurrence, negativity or relative entropy of entanglement. By parametrizing the set of two-qubit X-states and a family of unitary transformations that preserve the sparse structure of a two-qubit X-state density matrix, we obtain the parametric form of a unitary transformation that converts arbitrary two-qubit states into their X-counterparts. Moreover, we provide a semi-analytic prescription on how to set the parameters of this unitary transformation in order to preserve concurrence or negativity. We also explicitly construct a set of X-state density matrices, parametrized by their purity and concurrence, whose elements are in one-to-one correspondence with the points of the concurrence versus purity (CP) diagram for generic two-qubit states.Comment: 24 pages, 6 figures. v2 includes new references and minor changes (accepted version

Heuristic for estimation of multiqubit genuine multipartite entanglement

For every N-qubit density matrix written in the computational basis, an associated "X-density matrix" can be obtained by vanishing all entries out of the main- and anti-diagonals. It is very simple to compute the genuine multipartite (GM) concurrence of this associated N-qubit X-state, which, moreover, lower bounds the GM-concurrence of the original (non-X) state. In this paper, we rely on these facts to introduce and benchmark a heuristic for estimating the GM-concurrence of an arbitrary multiqubit mixed state. By explicitly considering two classes of mixed states, we illustrate that our estimates are usually very close to the standard lower bound on the GM-concurrence, being significantly easier to compute. In addition, while evaluating the performance of our proposed heuristic, we provide the first characterization of GM-entanglement in the steady states of the driven Dicke model at zero temperature.Comment: 19 pages, 5 figure

Fatigue Identification and Management in Flight Training: An Investigation of Collegiate Aviation Pilots

Pilot fatigue is a significant hazard affecting flight operations; Generally the product of one or more factors: Disrupted or lack of sleep; Inadequate food and or fluid intake; Mental; and Physical fatigue. Previous studies have focused on military and commercial flight operations; Little to nothing has been done to investigate fatigue identification & management by general aviation pilots

The Impact of Human Factors and Maintenance Documentation on Aviation Safety: An Analysis of 15 Years of Accident Data Through the PEAR Framework

Regardless of the type of maintenance performed on aircraft, instructions are to be used to provide the aviation technicians completing the maintenance activities with guidance on, and an outline of, the maintenance items to be performed and completed. However, the use of instructions does not guarantee the correct and proper completion of the maintenance activities as the instructions may be erroneous and/or maintenance personnel can misunderstand, misinterpret, or improperly follow the procedures outlined. Resulting maintenance errors can potentially result in aircraft accidents, as illustrated by Air Midwest Flight 5481. With the purpose of understanding how human factors associated with written maintenance instructions have contributed to aircraft accidents, the researchers qualitatively analyzed, using the people (P), environment (E), actions (A), resources (R) –PEAR –framework, 12 aircraft accidents that occurred from January 1, 2003,through December 31, 2017,under Part 121 or Part 135 operations in the United States that had maintenance instruction-related errors as contributing or causal factors. The detailed accident information, including causal factors, were retrieved from the aircraft accident reports provided by the National Transportation Safety Board (NTSB). The findings indicated that maintenance activities, specifically in terms of the adequacy and proper use of maintenance instructions, are largely impacted by human factor elements, such as the overall organizational environment and the resources available

EFFECT OF YEARLY SEASONS ON WILDLIFE STRIKES AT PART 139 AIRPORTS IN COLORADO

KEYWORDS: Aviation Safety, Wildlife Strikes, Yearly Seasons, Part 139 Airports, Colorado The need to enhance aviation safety is ongoing, and contribution in every aspect is needed. Aircraft wildlife strike is a growing aviation safety concern. Denver International Airport — a major airport — in Colorado, has observed the most wildlife strikes from 2009 to 2019. Colorado observes wildlife migration of specific species throughout the year. Therefore, a study on wildlife strikes at 14 Part 139 airports in Colorado would be significant and interesting. This ongoing study is an attempt to answer the following research questions: What is the number of wildlife strikes per 100,000 movements for each year during 2013–2020 at 14 Part 139 airports in Colorado? Are the seasons of the year a significant predictor of wildlife strikes at 14 Part 139 airports in Colorado? The researcher will answer the research questions by reviewing, sorting, and analyzing existing wildlife strike and aircraft operations data from 14 Part 139 airports in Colorado. The Wildlife Strike Index will be calculated and evaluated per season per airport from 2013 to 2022. This study adds to the body of knowledge by addressing the lack of published wildlife-strike data and information from Colorado’s airports

Utilizing UAS to Support Wildlife Hazard Management Efforts by Airport Operators

The FAA requires airports operating under the Code of Federal Regulations Part 139 to conduct a wildlife hazard assessment (WHA) when some wildlife-strike events have occurred at or near the airport. The WHA should be conducted by a Qualified Airport Wildlife Biologist (QAWB) and must contain several elements, including the identification of the wildlife species observed and their numbers; local movements; daily and seasonal occurrences; and the identification and location of features on and near the airport that could attract wildlife. Habitats and land-use practices at and around the airport are key factors affecting wildlife species and the size of their populations in the airport environment. The purpose of this ongoing study is to investigate how UAS technologies could be safely and effectively applied to identify hazardous wildlife species to aviation operations as well as potential wildlife hazard attractants within the airport jurisdiction. Researchers have used a DJI Mavic 2 Enterprise Dual drone with visual and thermal cameras to collect data. Data have been collected in a private airport in a “Class G” airspace. We have applied different risk mitigation strategies to mitigate risks associated with drone operations in an airport environment, including a visual observer during data collection, and an ADS-B flight box to obtain information of manned aircraft at and around the airport. Multiple flights were conducted in different days of the week as well as different times of the day. Noteworthy to mention we have had the technical support of QAWB throughout this study. Preliminary findings suggest that UAS can facilitate the observations made by a QAWB during a WHA, including the identification and assessment of potential wildlife attractants (e.g., wetlands), and the identification of wildlife species (e.g., White ibis). Additionally, initial findings indicate that UAS facilitates data collection in areas that are difficult to access by ground-based means (e.g., wetlands). Another key finding of this study was that our team could observe, and with the assistance of the QAWB identify different wildlife species and habitats simultaneously during each UAS flight. In different words, from a single image (video and/or picture) a QAWB could obtain valuable information about different wildlife species and related habitats. Lastly, results suggest that the versatility and speed of UAS (including their high-quality cameras and sensors) ensure that data can be collected more thoroughly and faster over large areas during a WHA

Dynamical trapping and relaxation of scalar gravitational fields

We present a framework for nonlinearly coupled scalar-tensor theory of gravity to address both inflation and core-collapse supernova problems. The unified approach is based on a novel dynamical trapping and relaxation of scalar gravity in highly energetic regimes. The new model provides a viable alternative mechanism of inflation free from various issues known to affect previous proposals. Furthermore, it could be related to observable violent astronomical events, specifically by releasing a significant amount of additional gravitational energy during core-collapse supernovae. A recent experiment at CERN relevant for testing this new model is briefly outlined.Comment: 4 pages; version to appear in PL