Magnetic Couplings in Edge-Sharing d7d^7 Compounds

High-spin $d^7$ Co(II) compounds have recently been identified as possible platforms for realising highly anisotropic and bond-dependent couplings featured in quantum-compass models such as the celebrated Kitaev model. In order to evaluate this potential, we consider all symmetry-allowed contributions to the magnetic exchange for ideal edge-sharing bonds. Though a combination of ab-initio and cluster many-body calculations we conclude that bond-dependent couplings are generally suppressed in favor of Heisenberg exchange for realistic materials. Consequences for several prominent materials including Na$_2$Co$_2$TeO$_6$ and BaCo$_2$(AsO$_4$)$_2$ are discussed.Comment: 12 pages, 8 figure

Models and Materials for Generalized Kitaev Magnetism

The exactly solvable Kitaev model on the honeycomb lattice has recently received enormous attention linked to the hope of achieving novel spin-liquid states with fractionalized Majorana-like excitations. In this review, we analyze the mechanism proposed by G. Jackeli and G. Khaliullin to identify Kitaev materials based on spin-orbital dependent bond interactions and provide a comprehensive overview of its implications in real materials. We set the focus on experimental results and current theoretical understanding of planar honeycomb systems (Na$_2$IrO$_3$, $\alpha$-Li$_2$IrO$_3$, and $\alpha$-RuCl$_3$), three-dimensional Kitaev materials ($\beta$- and $\gamma$-Li$_2$IrO$_3$), and other potential candidates, completing the review with the list of open questions awaiting new insights.Comment: updated references, published versio

There is a Bias in Aviation Against Research That is Perceived to be “Easy”

The purpose of conducting research is to make contributions to the body of knowledge. In managing research studies, researchers are often forced to make decisions on a series of tradeoffs due to scarce resources. They may have to select participants from certain accessible populations, limit the time required to conduct the study, or use a minimal number of researchers due to funding constraints. The purpose of this current study was to examine for a possible bias on the perceived value of scientific research based on the location in which the data was collected, the amount of time required to complete the study, and the number of researchers involved in the study. Over a series of four studies, 1796 total participants provided ratings on their perceived scientific value of the accomplished research. The findings indicated that those studies which were conducted in a laboratory, took more time, and used more researchers had more perceived scientific value than the exact same study completed in a classroom, in a shorter amount of time, and with fewer researchers. Additionally, ease/difficulty was shown to be a significant mediator, further providing evidence that the perceived ease or difficulty of the study was influencing the participants’ ratings

Consistency of Aviation Students When Taking the Private Pilot Knowledge Exam

Inconsistency is the enemy of performance. Several researchers have conducted a number of studies examining consistency in a variety of laboratory tasks; however, no research to date has looked at test-taking consistency in a real-world aviation environment. In this study, participants took a portion of the Federal Aviation Administration Private Pilot Knowledge Exam for credit in their Aeronautics 1 (private pilot ground school) course at their respective university. This was done twice: once after seven weeks and another time after 12 weeks into the semester. In order to measure consistency, participants took the same exam twice (questions were randomized across blocks). Participants were then asked to rate how consistent they thought they were in taking the two exams. For Exam 1, the overall consistency between the two blocks was r = .89; while the correlation between the self-assessment and consistency was rs = .55. For Exam 2, the overall consistency remained high at r = .80, while the correlation between the self-assessment and consistency fell to rs = .11. In contrast to previous laboratory data, the overall consistency between blocks was high. The self-assessment of consistency was fairly inaccurate, particularly in the second exam. The research indicates that participants still struggle to accurately self-assess their consistency

Comparison of two unknown pure quantum states

We investigate the extent to which we can establish whether or not two quantum systems have been prepared in the same state. We investigate the possibility of universal unambiguous state comparison. We show that it is impossible to conclusively identify two pure unknown states as being identical, and construct the optimal measurement for conclusively identifying them as being different. We then derive optimal strategies for state comparison when the state of each system is one of two known states