Interactions and charge fractionalization in an electronic Hong-Ou-Mandel interferometer

We consider an electronic analog of the Hong-Ou-Mandel (HOM) interferometer, where two single electrons travel along opposite chiral edge states and collide at a Quantum Point Contact. Studying the current noise, we show that because of interactions between co-propagating edge states, the degree of indistinguishability between the two electron wavepackets is dramatically reduced, leading to reduced contrast for the HOM signal. This decoherence phenomenon strongly depends on the energy resolution of the packets. Insofar as interactions cause charge fractionalization, we show that charge and neutral modes interfere with each other, leading to satellite dips or peaks in the current noise. Our calculations explain recent experimental results [E. Bocquillon, et al., Science 339, 1054(2013)] where an electronic HOM signal with reduced contrast was observed.Comment: 5 pages, 2 figure

Poissonian tunneling through an extended impurity in the quantum Hall effect

We consider transport in the Poissonian regime between edge states in the quantum Hall effect. The backscattering potential is assumed to be arbitrary, as it allows for multiple tunneling paths. We show that the Schottky relation between the backscattering current and noise can be established in full generality: the Fano factor corresponds to the electron charge (the quasiparticle charge) in the integer (fractional) quantum Hall effect, as in the case of purely local tunneling. We derive an analytical expression for the backscattering current, which can be written as that of a local tunneling current, albeit with a renormalized tunneling amplitude which depends on the voltage bias. We apply our results to a separable tunneling amplitude which can represent an extended point contact in the integer or in the fractional quantum Hall effect. We show that the differential conductance of an extended quantum point contact is suppressed by the interference between tunneling paths, and it has an anomalous dependence with respect to the bias voltage

(Article) Fracture of rigid solids: a discrete approach based on damaging interface modelling

International audienceWe describe the progressive and delayed fracture of rigid solids by a discrete modelling. Each rigid solid is considered as an assembly of particles with initial cohesive bonds, the latter decreasing progressively during the loading. A damaging interface model is proposed to describe this progressive phenomenon. The model has been implemented in a discrete element code. The first illustrative example, which is actually a parametric study, deals with the progressive damage and sudden fracture of a single interface submitted to an uniaxial tension. The second example is related to the crushing of an assembly of rigid solids--i.e. a granular medium--submitted to an oedometric compression

Aging and Attitudes Towards Strategic Uncertainty and Competition: An Artefactual Field Experiment in a Swiss Bank

We study the attitudes of junior and senior employees towards strategic uncertainty and competition, by means of a market entry game inspired by Camerer and Lovallo (1999). Seniors exhibit higher entry rates compared to juniors, especially when earnings depend on relative performance. This difference persists after controlling for attitudes towards non-strategic uncertainty and for beliefs on others' competitiveness and ability. Social image matters, as evidenced by the fact that seniors enter more when they predict others enter more and when they are matched with a majority of juniors. This contradicts the stereotype of risk averse and less competitive older employees

Intergenerational Attitudes Towards Strategic Uncertainty and Competition: A Field Experiment in a Swiss Bank

International audienceWith a market entry game inspired by Camerer and Lovallo (1999), we study the attitudes of junior and senior employees towards strategic uncertainty and competition. Seniors exhibit higher entry rates compared to juniors, especially when the market capacity is not too low or when earnings from entry depend on relative performance. This difference persists after controlling for attitudes towards non-strategic uncertainty and for beliefs on others' competitiveness and on relative ability. Seniors are more willing to compete when they predict a higher number of competitors. This contradicts the stereotype of less competitive older employees