Edge effects in the magnetic interference pattern of a ballistic SNS junction

We investigate the Josephson critical current $I_c(\Phi)$ of a wide superconductor-normal metal-superconductor (SNS) junction as a function of the magnetic flux $\Phi$ threading it. Electronic trajectories reflected from the side edges alter the function $I_c(\Phi)$ as compared to the conventional Fraunhofer-type dependence. At weak magnetic fields, $B\lesssim \Phi_0/d^2$, the edge effect lifts zeros in $I_c(\Phi)$ and gradually shifts the minima of that function toward half-integer multiples of the flux quantum. At $B>\Phi_0/d^2$, the edge effect leads to an accelerated decay of the critical current $I_c(\Phi)$ with increasing $\Phi$. At larger fields, eventually, the system is expected to cross into a regime of "classical" mesoscopic fluctuations that is specific for wide ballistic SNS junctions with rough edges.Comment: 14 pages, 8 figure

Probing the ν=2/3\nu=2/3 fractional quantum Hall edge by momentum-resolved tunneling

The nature of the fractional quantum Hall state with filling factor $\nu=2/3$ and its edge modes continues to remain an open problem in low-dimensional condensed matter physics. Here, we suggest an experimental setting to probe the $\nu=2/3$ edge by tunnel-coupling it to a $\nu=1$ integer quantum Hall edge in another layer of a two-dimensional electron gas (2DEG). In this double-layer geometry, the momentum of tunneling electrons may be boosted by an auxiliary magnetic field parallel to the two planes of 2DEGs. We evaluate the current as a function of bias voltage and the boosting magnetic field. Its threshold behavior yields information about the spectral function of the $\nu=2/3$ edge, in particular about the nature of the chiral edge modes. Our theory accounts also for the effects of Coulomb interaction and disorder.Comment: 5 pages, 5 figures, and supplementary material (5 pages, 1 figure

Strategies to valorise agrobiodiversity

The current food value chain is characterised by a highly standardised offer produced in an increasingly monotonous agricultural system. In parallel, there is a growing interest among consumers for traditional or regional crop varieties. The conservation of these crops is often done by civil society organisations like Arche Noah, Pro Specie Rara, Rete Semi Rurali, Réseau Semence Paysanne or Red Andaluza de Semillas. Some networks sell their food products in local niche markets, specialised stores and supermarkets. To increase their visibility, some producer groups in the networks are interested in developing or improving a label to valorise agrobiodiversity to the consumer. Based on a representative consumer survey in four European countries, we show that consumer awareness with respect to traditional, old varieties is low but the interest in "Diversifood", defined as more diverse, locally adapted, healthy and tasty produce, is substantial. Therefore, we state, that the availability of a label to valorise agrobiodiversity would respond to consumer needs and increase the visibility of the work done by the networks – but only if it is embedded in an appropriate communication strategy aimed at raising consumer awareness about agrobiodiversity

Editorial: Woody plants and forest ecosystems in a complex world—Ecological interactions and physiological functioning above and below ground

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