Focal Points and Economic Efficiency: Role of Relative Label Salience

We experimentally analyze efficiency-enhancing power of focal points in 2x2 Pareto-ranked coordination games. We find that the power of focal labels, when attached to the Pareto-efficient strategy, to promote efficiency critically depends upon the alternative strategy’s label salience. When the relative salience of our focal labels is considerably weaker, focal labels mostly fail to raise expected efficiency beyond the mixed-strategy prediction. But when the relative salience of our focal labels is markedly stronger, focal labels raise expected efficiency much beyond the mixed-strategy prediction. Furthermore, we find that focal labels’ efficiency-enhancing power decreases as a measure of risk-dominance increases across games.

Thermoelectrical Field Effects in Low Dimensional Structure Solar Cells

Taking into account the temperature gradients in solar cells, it is shown that their efficiency can be increased beyond the Shockley-Queisser limit (J. Appl. Phys. 32 (1961) 510). The driving force for this gain is the temperature gradient between this region and its surroundings. A quantitative theory is given. Though the effect is found to be weak in conventional solar cells, it is argued that it can be substantially increased by proper choice of materials and design of the device. In particular, it is shown that the insertion of a quantum well can enhance the efficiency beyond one of the single gap cell, due to the presence of temperature jumps at the heterojunctions.Comment: Published in Special issue Physica E 14 (1-2) on Nanostructures in Photovoltaic

High-efficiency WSi superconducting nanowire single-photon detectors for quantum state engineering in the near infrared

We report on high-efficiency superconducting nanowire single-photon detectors based on amorphous WSi and optimized at 1064 nm. At an operating temperature of 1.8 K, we demonstrated a 93% system detection efficiency at this wavelength with a dark noise of a few counts per second. Combined with cavity-enhanced spontaneous parametric down-conversion, this fiber-coupled detector enabled us to generate narrowband single photons with a heralding efficiency greater than 90% and a high spectral brightness of $0.6\times10^4$ photons/(s$\cdot$mW$\cdot$MHz). Beyond single-photon generation at large rate, such high-efficiency detectors open the path to efficient multiple-photon heralding and complex quantum state engineering