Gate Defined Quantum Confinement in Suspended Bilayer Graphene

Quantum confined devices that manipulate single electrons in graphene are emerging as attractive candidates for nanoelectronics applications. Previous experiments have employed etched graphene nanostructures, but edge and substrate disorder severely limit device functionality. Here we present a technique that builds quantum confined structures in suspended bilayer graphene with tunnel barriers defined by external electric fields that break layer inversion symmetry, thereby eliminating both edge and substrate disorder. We report clean quantum dot formation in two regimes: at zero magnetic field B using the single particle energy gap induced by a perpendicular electric field and at B > 0 using the quantum Hall ferromagnet {\nu} = 0 gap for confinement. Coulomb blockade oscillations exhibit periodicity consistent with electrostatic simulations based on local top gate geometry, a direct demonstration of local control over the band structure of graphene. This technology integrates single electron transport with high device quality and access to vibrational modes, enabling broad applications from electromechanical sensors to quantum bits.Comment: 22 pages, 9 figures, includes supplementary informatio

Universal scale factors relating mesonic fields and quark operators

Scale factor matrices relating mesonic fields in chiral Lagrangians and quark-level operators of QCD sum-rules are shown to be constrained by chiral symmetry, resulting in universal scale factors for each chiral nonet. Built upon this interplay between chiral Lagrangians and QCD sum-rules, the scale factors relating the $a_0$ isotriplet scalar mesons to their underlying quark composite field were recently determined. It is shown that the same technique when applied to $K_0^*$ isodoublet scalars reproduces the same scale factors, confirming the universality property and further validating this connection between chiral Lagrangians and QCD sum-rules which can have nontrivial impacts on our understanding of the low-energy QCD, in general, and the physics of scalar mesons in particular.Comment: 5 pages, 1 figure. arXiv admin note: text overlap with arXiv:1909.0724

On a Proper Meta-Analytic Model for Correlations

Combining statistical information across studies is a standard research tool in applied psychology. The most common approach in applied psychology is the fixed effects model. The fixed-effects approach assumes that individual study characteristics such as treatment conditions, study context, or individual differences do not influence study effect sizes. That is, that the majority of the differences between the effect sizes of different studies can be explained by sampling error alone. We critique the fixed-effects methodology for correlations and propose an advancement, the random-effects model, that ameliorates problems imposed by fixed-effects models. The random-effects approach explicitly incorporates between-study differences in data analysis and provides estimates of how those study characteristics influence the relationships among constructs of interest. Because they can model the influence of study characteristics, we assert that random-effects models have advantages for psychological research. Parameter estimates of both models are compared and evidence in favor of the random-effects approach is presented

The rent's too high: Self-archive for fair online publication costs

The main contributors of scientific knowledge, researchers, generally aim to disseminate their findings far and wide. And yet, publishing companies have largely kept these findings behind a paywall. With digital publication technology markedly reducing cost, this enduring wall seems disproportionate and unjustified; moreover, it has sparked a topical exchange concerning how to modernize academic publishing. This discussion, however, seems to focus on how to compensate major publishers for providing open access through a "pay to publish" model, in turn transferring financial burdens from libraries to authors and their funders. Large publishing companies, including Elsevier, Springer Nature, Wiley, PLoS, and Frontiers, continue to earn exorbitant revenues each year, hundreds of millions of dollars of which now come from processing charges for open-access articles. A less expensive and equally accessible alternative exists: widespread self-archiving of peer-reviewed articles. All we need is awareness of this alternative and the will to employ itComment: 8 pages, 1 figure, 19 reference