Electrical observation of a tunable band gap in bilayer graphene nanoribbons at room temperature

We investigate the transport properties of double-gated bilayer graphene nanoribbons at room temperature. The devices were fabricated using conventional CMOS-compatible processes. By analyzing the dependence of the resistance at the charge neutrality point as a function of the electric field applied perpendicular to the graphene surface, we show that a band gap in the density of states opens, reaching an effective value of ~sim50 meV. This demonstrates the potential of bilayer graphene as FET channel material in a conventional CMOS environment.Comment: 3 pages, 3 figure

Efficient fluorescence collection from trapped ions with an integrated spherical mirror

Efficient collection of fluorescence from trapped ions is crucial for quantum optics and quantum computing applications, specifically, for qubit state detection and in generating single photons for ion-photon and remote ion entanglement. In a typical setup, only a few per cent of ion fluorescence is intercepted by the aperture of the imaging optics. We employ a simple metallic spherical mirror integrated with a linear Paul ion trap to achieve photon collection efficiency of at least 10% from a single Ba$^+$ ion. An aspheric corrector is used to reduce the aberrations caused by the mirror and achieve high image quality.Comment: 5 pages and 4 figure

The Pairing Matrix in Discrete Electromagnetism On the Geometry of Discrete de Rham Currents

We introduce pairing matrices on simplicial cell complexes in discrete electromagnetism as a means to avoid the explicit construction of a topologically dual complex. Interestingly, the Finite Element Method with first-order Whitney elements â when it is looked upon from a cell-method perspective â features pairing matrices and thus an implicitly defined dual mesh. We show that the pairing matrix can be used to construct discrete energy products. In this exercise we find that different formalisms lead to equivalent matrix representations. Discrete de Rham currents are an elegant way to subsume these geometrically equivalent but formally distinct ways of defining energy-products

Hyperfine and Optical Barium Ion Qubits

State preparation, qubit rotation, and high fidelity readout are demonstrated for two separate \baseven qubit types. First, an optical qubit on the narrow 6S$_{1/2}$ to 5D$_{5/2}$ transition at 1.76 $\mu$m is implemented. Then, leveraging the techniques developed there for readout, a ground state hyperfine qubit using the magnetically insensitive transition at 8 GHz is accomplished

Measurement of Lande g factor of 5D5/2 state of BaII with a single trapped ion

We present the first terrestrial measurement of the Lande g factor of the 5D5/2 state of singly ionized barium. Measurements were performed on single Doppler-cooled 138Ba+ ions in a linear Paul trap. A frequency-stabilized fiber laser with nominal wavelength 1.762 um was scanned across the 6S1/25D5/2 transition to spectroscopically resolve transitions between Zeeman sublevels of the ground and excited states. From the relative positions of the four narrow transitions observed at several different values for the applied magnetic field, we find a value of 1.2020+/-0.0005 for g of 5D5/2.Comment: 3 figure

Learning outcomes for American Sign Language skill levels 1-4

This document describes measurable learning outcomes for American Sign Language (ASL) levels 1 – 4. A history of ASL provides the background and foundation for the document and includes an overview of teaching and learning ASL in the United States. The processes leading to the creation of the outcomes for ASL levels 1 – 4 are discussed and incorporate the development of ASL outcomes for college-level courses. Information about how the outcomes were adapted was taken, with permission, from the American Council on the Teaching of Foreign Languages (ACTFL). The key premise of ACTFL’s “5 Cs” are: Communication, Cultures, Connections, Comparisons, and Communities and are highlighted in the document. Recommendations by the American Sign Language Teachers Association (ASLTA) and stakeholders in New York State are included, along with the number and content of instructional contact hours in a supervised language laboratory. The measurable learning outcomes following ACTFL’s 5 Cs make up the majority of the document. Regardless of teaching style, and acknowledging that each teacher is unique and has his or her own teaching style, the goals and objectives for measuring student progress must be met. References, a resource section, and a reading section are included, as well as appendices with a glossary and information pertaining to ASL performance interviews

Modeling of primary dendrite arm spacing variations in thin-slab casting of low carbon and low alloy steels

Solidification structure of a High Strength Low Alloy (HSLA) steel, in terms of dendrite arm spacing distribution across the shell thickness, is studied in a breakout shell from a thin-slab caster at Tata Steel in IJmuiden. Columnar dendrites were found to be the predominant morphology throughout the shell with size variations across the shell thickness. Primary Dendrite Arm Spacing (PDAS) increases by increasing the distance from meniscus or slab surface. Subsequently, a model is proposed to describe the variation of the PDAS with the shell thickness (the distance from slab surface) under solidifiction conditions experienced in the primary cooling zone of thin-slab casting. The proposed relationship related the PDAS to the shell thickness and, hence, can be used as a tool for predicting solidifcation structure and optimizing the thin-slab casting of low alloy steels

Precision measurement of the branching ratio in the 6P3/2 decay of BaII with a single trapped ion

We present a measurement of the branching ratios from the 6P3/2 state of BaII into all dipoleallowed decay channels (6S1/2, 5D3/2 and 5D5/2). Measurements were performed on single 138Ba+ ions in a linear Paul trap with a frequency-doubled mode-locked Ti:Sapphire laser resonant with the 6S1/2->6P3/2 transition at 455 nm by detection of electron shelving into the dark 5D5/2 state. By driving a pi Rabi rotation with a single femtosecond pulse, a absolute measurement of the branching ratio to 5D5/2 state was performed. Combined with a measurement of the relative decay rates into 5D3/2 and 5D5/2 states performed with long trains of highly attenuated 455 nm pulses, it allowed the extraction of the absolute ratios of the other two decays. Relative strengths normalized to unity are found to be 0.756+/-0.046, 0.0290+/-0.0015 and 0.215+/-0.0064 for 6S1/2, 5D3/2 and 5D5/2 respectively. This approximately constitutes a threefold improvement over the best previous measurements and is a sufficient level of precision to compare to calculated values for dipole matrix elements.Comment: 6 pages, 5 figures, 1 tabl

Constructed Action in American Sign Language: A Look at Second Language Learners in a Second Modality

Constructed action is a cover term used in signed language linguistics to describe multi-functional constructions which encode perspective-taking and viewpoint. Within constructed action, viewpoint constructions serve to create discourse coherence by allowing signers to share perspectives and psychological states. Character, observer, and blended viewpoint constructions have been well documented in signed language literature in Deaf signers. However, little is known about hearing second language learners’ use of constructed action or about the acquisition and use of viewpoint constructions. We investigate the acquisition of viewpoint constructions in 11 college students acquiring American Sign Language (ASL) as a second language in a second modality (M2L2). Participants viewed video clips from the cartoon Canary Row and were asked to “retell the story as if you were telling it to a deaf friend”. We analyzed the signed narratives for time spent in character, observer, and blended viewpoints. Our results show that despite predictions of an overall increase in use of all types of viewpoint constructions, students varied in their time spent in observer and character viewpoints, while blended viewpoint was rarely observed. We frame our preliminary findings within the context of M2L2 learning, briefly discussing how gestural strategies used in multimodal speech-gesture constructions may influence learning trajectories