Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer

Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations

Biquadratic Interactions and Spin-Peierls Transition in the Spin-1 Chain LiVGe2O6

The magnetic susceptibility of a new one-dimensional S = 1 system, the vanadium oxide LiVGe2O6, has been measured. Contrary to previous S = 1 chains, it exhibits an abrupt drop at 22 K typical of a spin-Peierls transition, and it is consistent with a gapless spectrum above this temperature. We propose that this behavior is due to the presence of a significant biquadratic exchange interaction, a suggestion supported by quantum chemistry calculations that take into account the quasidegeneracy of the t2g levels.link_to_subscribed_fulltex

Minimization of errors in narrowband laser phase noise measurements based on reference measurement channels

We propose a novel scheme for laser phase noise measurements with minimized sensitivity to external fluctuations including interferometer vibration, temperature instability, other low-frequency noise and relative intensity noise. In order to minimize the effect of these external fluctuations, we employ simultaneous measurement of two spectrally separated channels in the scheme. We present an algorithm for selection of the desired signal to extract the phase noise. Experimental results demonstrate potential of the suggested scheme for a wide range of technological applications

Beyond the brotherhood: Skoal Bandits’ role in the evolution of marketing moist smokeless tobacco pouches

Background Since 2006, “snus” smokeless tobacco has been sold in the U.S.. However, U.S. Smokeless Tobacco (USST) and Swedish Match developed and marketed pouched moist snuff tobacco (MST) since 1973. Material and Methods Analysis of previously secret tobacco documents, advertisements and trade press. Results USST partnered with Swedish Match, forming United Scandia International to develop pouch products as part of the “Lotus Project.” Pouched MST was not commonly used, either in Sweden or the U.S. prior to the Lotus Project’s innovation in 1973. The project aimed to transform smokeless tobacco from being perceived as an “unsightly habit of old men” into a relevant, socially acceptable urban activity, targeting 15–35 year-old men. While USST’s initial pouched product “Good Luck,” never gained mainstream traction, Skoal Bandits captured significant market share after its 1983 introduction. Internal market research found that smokers generally used Skoal Bandits in smokefree environments, yet continued to smoke cigarettes in other contexts. Over time, pouch products increasingly featured increased flavor, size, nicotine strength and user imagery variation. Conclusions Marlboro and Camel Snus advertising mirrors historical advertising for Skoal Bandits, designed to recruit new users and smokers subjected to smokefree places. Despite serious efforts, pouched MST marketing has been unable to dispel its association with traditional smokeless tobacco stereotypes as macho and rural. Public education efforts to discourage new users and dual use of MST and cigarettes should emphasize that “new” pouch products are simply repackaging “old” smokeless tobacco