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Quantum materials can display physical phenomena rooted in the geometry of electronic wavefunctions. The corresponding geometric tensor is characterized by an emergent field known as the Berry curvature (BC). Large BCs typically arise when electronic states with different spin, orbital or sublattice quantum numbers hybridize at finite crystal momentum. In all the materials known to date, the BC is triggered by the hybridization of a single type of quantum number. Here we report the discovery of the first material system having both spin- and orbital-sourced BC: LaAlO3/SrTiO3interfaces grown along the [111] direction. We independently detect these two sources and probe the BC associated to the spin quantum number through the measurements of an anomalous planar Hall effect. The observation of a nonlinear Hall effect with time-reversal symmetry signals large orbital-mediated BC dipoles. The coexistence of different forms of BC enables the combination of spintronic and optoelectronic functionalities in a single material.

With the explosion of new blogs and blog search engines, the 'blogosphere' will become the single richest source of material news leaks in the history of the stock market. This […]

Single-photon sources are basic building blocks for quantum communications, processing, and metrology. Solid-state quantum emitters in semiconductors have the potential for robust and reliable generation of photons, and atomically thin transition metal dichalcogenides, such as MoS_2, MoSe_2, WS_2, and WSe_2, are a promising new class of two-dimensional semiconductors with a direct optical bandgap in the visible or near-IR. Here, we observe bright and stable single-photon emission from localized excitons in a monolayer of tungsten diselenide (WSe_2). The emitters appear at the edges of the flakes and are linearly polarized. The spectral width of their emission is below 120 μeV in a freestanding WSe_2 monolayer. Photoluminescence excitation spectroscopy reveals the excitonic nature of the emitters and provides evidence that these single excitons originate from free excitons trapped in local potential wells at the edges of the atomically thin flakes. We find that the emitters can also be deterministically created by scratching the WSe_2 monolayer. Their excellent spectral stability implies that these localized single-photon emitters could find application in optoelectronics. Our results light the way to single exciton physics and quantum optics with atomically thin semiconductors.

FAMILY PRACTICE NEWS received a huge response to "Maintaining Certification," a Guest Editorial written by Dr. Richard Feldman (Aug. 15, 2004, p. 10). Below are some of the comments: Dr. [...]

From Gary Steele, MW Subscriber Given the current publicity surrounding the singles chart, it certainly seems longer than two months ago when the Darkness and Michael Andrews/Gary Jules singles were [...]

How unfortunate that after the charts are given renewed publicity by the Coca Cola sponsorship deal, the All New Top of the Pops show seems to reduce its significance. During [...]

Gary Steele I have just completed reading the new edition of Music Week and wanted to forward some comments to you. There's a lot more news and articles to read [...]

A Cooper-pair box qubit is used to squeeze the energy of a heavy oscillating membrane towards a quantum energy eigenstate, bringing measurements of how mass and quantum mechanics interact one step closer.

The article focuses on the first postage due stamps issued by Canada on July 1, 1906. It discusses the purpose of the postage due stamps in the proper accounting of the post office cash box. The author explores the uses of three postage due stamps valued 1 cent, 2 cents and 5 cents from 1906 to 1930, offering samples of letters where these have been applied.

The Raven's Coloured Progressive Matrices (CPM) test is internationally recognised as a culture-fair test of non-verbal intelligence, designed for use with children between the ages of 51/4 and 111/2 years. The Raven's CPM is used extensively across a wide variety of settings in South Africa. However, more appropriate local normative data has yet to be established. This pilot study seeks to establish normative data for this instrument for a population of isiXhosa-speaking primary school children in a peri-urban area of the Eastern Cape, South Africa. The booklet version of the test was used in group format and according to an alternative method of test administration (using isiXhosa instructions) developed by Vass (1992). The final normative sample consisted of 197 male and 182 female isiXhosa-speaking children in Grades 2 to 7 (n = 379). This study presents a set of local norms for the age group, 6 to 11 years. In addition, it was found that older children (>11 years of age) who have not yet reached certain educational levels, have also not reached the plateau, as anticipated, in their performance on this test. In addition, therefore, is a set of 'older norms' also presented and the issues related to grade versus age norms are debated. The tendency for this normative sample to perform lower than their Western counterparts on this test was also noted and debated. The tendency for males to outperform females was also recorded and it was found that this is in line with previous research on similar populations. The study concludes that there is an urgent need for more appropriate South African normative data for this test; and that, when assessing African children from disadvantaged backgrounds, further research into the effects of cultural and socio-economic factors and gender on non-verbal analogical reasoning tasks (and performance on this test in particular) is required.

In this article the author provides advice to companies who are reluctant about using social media sites to expand their businesses. He cites the most common fears which prevent them from doing so, including loss of control over content, possible security breaches, and concerns over privacy. Solutions advised include having a team of experts handle security, having the information technology department control social media, and setting defined boundaries on who can post what.

Several letters to the editor are presented in response to articles in the April 23, 2007 issue, including "Friendly Fire," "The Team That Invented Football," and "Getting His Feet Wet."

Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike in conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and valley freedom. The interplay between the two is the focus of this review. The energy levels associated with each degree of freedom, and the spin-orbit coupling between them, are explained, together with their consequences for transport measurements through nanotube quantum dots. In double quantum dots, the combination of quantum numbers modifies the selection rules of Pauli blockade. This can be exploited to read out spin and valley qubits and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron-electron interactions in one dimension strongly modifies their transport behavior. Interaction between electrons inside and outside a quantum dot is manifested in SU(4) Kondo behavior and level renormalization. Interaction within a dot leads to Wigner molecules and more complex correlated states. This review takes an experimental perspective informed by recent advances in theory. As well as the well-understood overall picture, open questions for the field are also clearly stated. These advances position nanotubes as a leading system for the study of spin and valley physics in one dimension where electronic disorder and hyperfine interaction can both be reduced to a low level. [ABSTRACT FROM AUTHOR]